freebsd-skq/sys/kern/kern_event.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
* Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org>
* Copyright (c) 2009 Apple, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
2003-06-11 00:56:59 +00:00
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ktrace.h"
#include "opt_kqueue.h"
Decode kevent structures logged via ktrace(2) in kdump. - Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of structures. The structure name in the record payload is preceded by a size_t containing the size of the individual structures. Use this to replace the previous code that dumped the kevent arrays dumped for kevent(). kdump is now able to decode the kevent structures rather than dumping their contents via a hexdump. One change from before is that the 'changes' and 'events' arrays are not marked with separate 'read' and 'write' annotations in kdump output. Instead, the first array is the 'changes' array, and the second array (only present if kevent doesn't fail with an error) is the 'events' array. For kevent(), empty arrays are denoted by an entry with an array containing zero entries rather than no record. - Move kevent decoding tables from truss to libsysdecode. This adds three new functions to decode members of struct kevent: sysdecode_kevent_filter, sysdecode_kevent_flags, and sysdecode_kevent_fflags. kdump uses these helper functions to pretty-print kevent fields. - Move structure definitions for freebsd11 and freebsd32 kevent structures to <sys/event.h> so that they can be shared with userland. The 32-bit structures are only exposed if _WANT_KEVENT32 is defined. The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is defined. The 32-bit freebsd11 structure requires both. - Decode freebsd11 kevent structures in truss for the compat11.kevent() system call. - Log 32-bit kevent structures via ktrace for 32-bit compat kevent() system calls. - While here, constify the 'void *data' argument to ktrstruct(). Reviewed by: kib (earlier version) MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D12470
2017-11-25 04:49:12 +00:00
#ifdef COMPAT_FREEBSD11
#define _WANT_FREEBSD11_KEVENT
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/capsicum.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/rwlock.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/unistd.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/filio.h>
#include <sys/fcntl.h>
#include <sys/kthread.h>
#include <sys/selinfo.h>
#include <sys/queue.h>
#include <sys/event.h>
#include <sys/eventvar.h>
#include <sys/poll.h>
#include <sys/protosw.h>
#include <sys/resourcevar.h>
#include <sys/sigio.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/syscallsubr.h>
#include <sys/taskqueue.h>
#include <sys/uio.h>
#include <sys/user.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <machine/atomic.h>
#include <vm/uma.h>
static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
/*
* This lock is used if multiple kq locks are required. This possibly
* should be made into a per proc lock.
*/
static struct mtx kq_global;
MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
#define KQ_GLOBAL_LOCK(lck, haslck) do { \
if (!haslck) \
mtx_lock(lck); \
haslck = 1; \
} while (0)
#define KQ_GLOBAL_UNLOCK(lck, haslck) do { \
if (haslck) \
mtx_unlock(lck); \
haslck = 0; \
} while (0)
TASKQUEUE_DEFINE_THREAD(kqueue_ctx);
static int kevent_copyout(void *arg, struct kevent *kevp, int count);
static int kevent_copyin(void *arg, struct kevent *kevp, int count);
static int kqueue_register(struct kqueue *kq, struct kevent *kev,
struct thread *td, int mflag);
static int kqueue_acquire(struct file *fp, struct kqueue **kqp);
static void kqueue_release(struct kqueue *kq, int locked);
static void kqueue_destroy(struct kqueue *kq);
static void kqueue_drain(struct kqueue *kq, struct thread *td);
static int kqueue_expand(struct kqueue *kq, struct filterops *fops,
uintptr_t ident, int mflag);
static void kqueue_task(void *arg, int pending);
static int kqueue_scan(struct kqueue *kq, int maxevents,
struct kevent_copyops *k_ops,
const struct timespec *timeout,
struct kevent *keva, struct thread *td);
static void kqueue_wakeup(struct kqueue *kq);
static struct filterops *kqueue_fo_find(int filt);
static void kqueue_fo_release(int filt);
struct g_kevent_args;
static int kern_kevent_generic(struct thread *td,
struct g_kevent_args *uap,
Decode kevent structures logged via ktrace(2) in kdump. - Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of structures. The structure name in the record payload is preceded by a size_t containing the size of the individual structures. Use this to replace the previous code that dumped the kevent arrays dumped for kevent(). kdump is now able to decode the kevent structures rather than dumping their contents via a hexdump. One change from before is that the 'changes' and 'events' arrays are not marked with separate 'read' and 'write' annotations in kdump output. Instead, the first array is the 'changes' array, and the second array (only present if kevent doesn't fail with an error) is the 'events' array. For kevent(), empty arrays are denoted by an entry with an array containing zero entries rather than no record. - Move kevent decoding tables from truss to libsysdecode. This adds three new functions to decode members of struct kevent: sysdecode_kevent_filter, sysdecode_kevent_flags, and sysdecode_kevent_fflags. kdump uses these helper functions to pretty-print kevent fields. - Move structure definitions for freebsd11 and freebsd32 kevent structures to <sys/event.h> so that they can be shared with userland. The 32-bit structures are only exposed if _WANT_KEVENT32 is defined. The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is defined. The 32-bit freebsd11 structure requires both. - Decode freebsd11 kevent structures in truss for the compat11.kevent() system call. - Log 32-bit kevent structures via ktrace for 32-bit compat kevent() system calls. - While here, constify the 'void *data' argument to ktrstruct(). Reviewed by: kib (earlier version) MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D12470
2017-11-25 04:49:12 +00:00
struct kevent_copyops *k_ops, const char *struct_name);
static fo_ioctl_t kqueue_ioctl;
static fo_poll_t kqueue_poll;
static fo_kqfilter_t kqueue_kqfilter;
static fo_stat_t kqueue_stat;
static fo_close_t kqueue_close;
static fo_fill_kinfo_t kqueue_fill_kinfo;
static struct fileops kqueueops = {
.fo_read = invfo_rdwr,
.fo_write = invfo_rdwr,
.fo_truncate = invfo_truncate,
.fo_ioctl = kqueue_ioctl,
.fo_poll = kqueue_poll,
.fo_kqfilter = kqueue_kqfilter,
.fo_stat = kqueue_stat,
.fo_close = kqueue_close,
.fo_chmod = invfo_chmod,
.fo_chown = invfo_chown,
.fo_sendfile = invfo_sendfile,
.fo_fill_kinfo = kqueue_fill_kinfo,
};
static int knote_attach(struct knote *kn, struct kqueue *kq);
static void knote_drop(struct knote *kn, struct thread *td);
static void knote_drop_detached(struct knote *kn, struct thread *td);
static void knote_enqueue(struct knote *kn);
static void knote_dequeue(struct knote *kn);
static void knote_init(void);
static struct knote *knote_alloc(int mflag);
static void knote_free(struct knote *kn);
static void filt_kqdetach(struct knote *kn);
static int filt_kqueue(struct knote *kn, long hint);
static int filt_procattach(struct knote *kn);
static void filt_procdetach(struct knote *kn);
static int filt_proc(struct knote *kn, long hint);
static int filt_fileattach(struct knote *kn);
static void filt_timerexpire(void *knx);
static int filt_timerattach(struct knote *kn);
static void filt_timerdetach(struct knote *kn);
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
static void filt_timerstart(struct knote *kn, sbintime_t to);
static void filt_timertouch(struct knote *kn, struct kevent *kev,
u_long type);
static int filt_timervalidate(struct knote *kn, sbintime_t *to);
static int filt_timer(struct knote *kn, long hint);
static int filt_userattach(struct knote *kn);
static void filt_userdetach(struct knote *kn);
static int filt_user(struct knote *kn, long hint);
static void filt_usertouch(struct knote *kn, struct kevent *kev,
u_long type);
static struct filterops file_filtops = {
.f_isfd = 1,
.f_attach = filt_fileattach,
};
static struct filterops kqread_filtops = {
.f_isfd = 1,
.f_detach = filt_kqdetach,
.f_event = filt_kqueue,
};
/* XXX - move to kern_proc.c? */
static struct filterops proc_filtops = {
.f_isfd = 0,
.f_attach = filt_procattach,
.f_detach = filt_procdetach,
.f_event = filt_proc,
};
static struct filterops timer_filtops = {
.f_isfd = 0,
.f_attach = filt_timerattach,
.f_detach = filt_timerdetach,
.f_event = filt_timer,
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
.f_touch = filt_timertouch,
};
static struct filterops user_filtops = {
.f_attach = filt_userattach,
.f_detach = filt_userdetach,
.f_event = filt_user,
.f_touch = filt_usertouch,
};
static uma_zone_t knote_zone;
static unsigned int kq_ncallouts = 0;
static unsigned int kq_calloutmax = 4 * 1024;
SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
&kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
/* XXX - ensure not influx ? */
#define KNOTE_ACTIVATE(kn, islock) do { \
if ((islock)) \
mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \
else \
KQ_LOCK((kn)->kn_kq); \
(kn)->kn_status |= KN_ACTIVE; \
if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
knote_enqueue((kn)); \
if (!(islock)) \
KQ_UNLOCK((kn)->kn_kq); \
} while(0)
#define KQ_LOCK(kq) do { \
mtx_lock(&(kq)->kq_lock); \
} while (0)
#define KQ_FLUX_WAKEUP(kq) do { \
if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \
(kq)->kq_state &= ~KQ_FLUXWAIT; \
wakeup((kq)); \
} \
} while (0)
#define KQ_UNLOCK_FLUX(kq) do { \
KQ_FLUX_WAKEUP(kq); \
mtx_unlock(&(kq)->kq_lock); \
} while (0)
#define KQ_UNLOCK(kq) do { \
mtx_unlock(&(kq)->kq_lock); \
} while (0)
#define KQ_OWNED(kq) do { \
mtx_assert(&(kq)->kq_lock, MA_OWNED); \
} while (0)
#define KQ_NOTOWNED(kq) do { \
mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \
} while (0)
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
static struct knlist *
kn_list_lock(struct knote *kn)
{
struct knlist *knl;
knl = kn->kn_knlist;
if (knl != NULL)
knl->kl_lock(knl->kl_lockarg);
return (knl);
}
static void
kn_list_unlock(struct knlist *knl)
{
bool do_free;
if (knl == NULL)
return;
do_free = knl->kl_autodestroy && knlist_empty(knl);
knl->kl_unlock(knl->kl_lockarg);
if (do_free) {
knlist_destroy(knl);
free(knl, M_KQUEUE);
}
}
static bool
kn_in_flux(struct knote *kn)
{
return (kn->kn_influx > 0);
}
static void
kn_enter_flux(struct knote *kn)
{
KQ_OWNED(kn->kn_kq);
MPASS(kn->kn_influx < INT_MAX);
kn->kn_influx++;
}
static bool
kn_leave_flux(struct knote *kn)
{
KQ_OWNED(kn->kn_kq);
MPASS(kn->kn_influx > 0);
kn->kn_influx--;
return (kn->kn_influx == 0);
}
#define KNL_ASSERT_LOCK(knl, islocked) do { \
if (islocked) \
KNL_ASSERT_LOCKED(knl); \
else \
KNL_ASSERT_UNLOCKED(knl); \
} while (0)
#ifdef INVARIANTS
#define KNL_ASSERT_LOCKED(knl) do { \
knl->kl_assert_locked((knl)->kl_lockarg); \
} while (0)
#define KNL_ASSERT_UNLOCKED(knl) do { \
knl->kl_assert_unlocked((knl)->kl_lockarg); \
} while (0)
#else /* !INVARIANTS */
#define KNL_ASSERT_LOCKED(knl) do {} while(0)
#define KNL_ASSERT_UNLOCKED(knl) do {} while (0)
#endif /* INVARIANTS */
#ifndef KN_HASHSIZE
#define KN_HASHSIZE 64 /* XXX should be tunable */
#endif
#define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
static int
filt_nullattach(struct knote *kn)
{
return (ENXIO);
};
struct filterops null_filtops = {
.f_isfd = 0,
.f_attach = filt_nullattach,
};
/* XXX - make SYSINIT to add these, and move into respective modules. */
extern struct filterops sig_filtops;
extern struct filterops fs_filtops;
/*
* Table for for all system-defined filters.
*/
static struct mtx filterops_lock;
MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops",
MTX_DEF);
static struct {
struct filterops *for_fop;
int for_nolock;
int for_refcnt;
} sysfilt_ops[EVFILT_SYSCOUNT] = {
{ &file_filtops, 1 }, /* EVFILT_READ */
{ &file_filtops, 1 }, /* EVFILT_WRITE */
{ &null_filtops }, /* EVFILT_AIO */
{ &file_filtops, 1 }, /* EVFILT_VNODE */
{ &proc_filtops, 1 }, /* EVFILT_PROC */
{ &sig_filtops, 1 }, /* EVFILT_SIGNAL */
{ &timer_filtops, 1 }, /* EVFILT_TIMER */
{ &file_filtops, 1 }, /* EVFILT_PROCDESC */
{ &fs_filtops, 1 }, /* EVFILT_FS */
{ &null_filtops }, /* EVFILT_LIO */
{ &user_filtops, 1 }, /* EVFILT_USER */
{ &null_filtops }, /* EVFILT_SENDFILE */
{ &file_filtops, 1 }, /* EVFILT_EMPTY */
};
/*
* Simple redirection for all cdevsw style objects to call their fo_kqfilter
* method.
*/
static int
filt_fileattach(struct knote *kn)
{
2004-08-13 07:38:58 +00:00
return (fo_kqfilter(kn->kn_fp, kn));
}
/*ARGSUSED*/
static int
kqueue_kqfilter(struct file *fp, struct knote *kn)
{
struct kqueue *kq = kn->kn_fp->f_data;
if (kn->kn_filter != EVFILT_READ)
return (EINVAL);
kn->kn_status |= KN_KQUEUE;
kn->kn_fop = &kqread_filtops;
knlist_add(&kq->kq_sel.si_note, kn, 0);
return (0);
}
static void
filt_kqdetach(struct knote *kn)
{
struct kqueue *kq = kn->kn_fp->f_data;
knlist_remove(&kq->kq_sel.si_note, kn, 0);
}
/*ARGSUSED*/
static int
filt_kqueue(struct knote *kn, long hint)
{
struct kqueue *kq = kn->kn_fp->f_data;
kn->kn_data = kq->kq_count;
return (kn->kn_data > 0);
}
/* XXX - move to kern_proc.c? */
static int
filt_procattach(struct knote *kn)
{
struct proc *p;
int error;
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
bool exiting, immediate;
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
exiting = immediate = false;
if (kn->kn_sfflags & NOTE_EXIT)
p = pfind_any(kn->kn_id);
else
p = pfind(kn->kn_id);
if (p == NULL)
return (ESRCH);
if (p->p_flag & P_WEXIT)
exiting = true;
if ((error = p_cansee(curthread, p))) {
PROC_UNLOCK(p);
return (error);
}
kn->kn_ptr.p_proc = p;
kn->kn_flags |= EV_CLEAR; /* automatically set */
/*
* Internal flag indicating registration done by kernel for the
* purposes of getting a NOTE_CHILD notification.
*/
if (kn->kn_flags & EV_FLAG2) {
kn->kn_flags &= ~EV_FLAG2;
kn->kn_data = kn->kn_sdata; /* ppid */
kn->kn_fflags = NOTE_CHILD;
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK);
immediate = true; /* Force immediate activation of child note. */
}
/*
* Internal flag indicating registration done by kernel (for other than
* NOTE_CHILD).
*/
if (kn->kn_flags & EV_FLAG1) {
kn->kn_flags &= ~EV_FLAG1;
}
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
knlist_add(p->p_klist, kn, 1);
/*
* Immediately activate any child notes or, in the case of a zombie
* target process, exit notes. The latter is necessary to handle the
* case where the target process, e.g. a child, dies before the kevent
* is registered.
*/
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
if (immediate || (exiting && filt_proc(kn, NOTE_EXIT)))
KNOTE_ACTIVATE(kn, 0);
2001-01-24 00:35:12 +00:00
PROC_UNLOCK(p);
return (0);
}
/*
* The knote may be attached to a different process, which may exit,
* leaving nothing for the knote to be attached to. So when the process
* exits, the knote is marked as DETACHED and also flagged as ONESHOT so
* it will be deleted when read out. However, as part of the knote deletion,
* this routine is called, so a check is needed to avoid actually performing
* a detach, because the original process does not exist any more.
*/
/* XXX - move to kern_proc.c? */
static void
filt_procdetach(struct knote *kn)
{
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
knlist_remove(kn->kn_knlist, kn, 0);
kn->kn_ptr.p_proc = NULL;
}
/* XXX - move to kern_proc.c? */
static int
filt_proc(struct knote *kn, long hint)
{
struct proc *p;
u_int event;
p = kn->kn_ptr.p_proc;
if (p == NULL) /* already activated, from attach filter */
return (0);
/* Mask off extra data. */
event = (u_int)hint & NOTE_PCTRLMASK;
/* If the user is interested in this event, record it. */
if (kn->kn_sfflags & event)
kn->kn_fflags |= event;
/* Process is gone, so flag the event as finished. */
if (event == NOTE_EXIT) {
kn->kn_flags |= EV_EOF | EV_ONESHOT;
kn->kn_ptr.p_proc = NULL;
if (kn->kn_fflags & NOTE_EXIT)
kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig);
if (kn->kn_fflags == 0)
kn->kn_flags |= EV_DROP;
return (1);
}
return (kn->kn_fflags != 0);
}
/*
* Called when the process forked. It mostly does the same as the
* knote(), activating all knotes registered to be activated when the
* process forked. Additionally, for each knote attached to the
* parent, check whether user wants to track the new process. If so
* attach a new knote to it, and immediately report an event with the
* child's pid.
*/
void
knote_fork(struct knlist *list, int pid)
{
struct kqueue *kq;
struct knote *kn;
struct kevent kev;
int error;
MPASS(list != NULL);
KNL_ASSERT_LOCKED(list);
if (SLIST_EMPTY(&list->kl_list))
return;
memset(&kev, 0, sizeof(kev));
SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
kq = kn->kn_kq;
KQ_LOCK(kq);
if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) {
KQ_UNLOCK(kq);
continue;
}
/*
* The same as knote(), activate the event.
*/
if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
if (kn->kn_fop->f_event(kn, NOTE_FORK))
KNOTE_ACTIVATE(kn, 1);
KQ_UNLOCK(kq);
continue;
}
/*
* The NOTE_TRACK case. In addition to the activation
* of the event, we need to register new events to
* track the child. Drop the locks in preparation for
* the call to kqueue_register().
*/
kn_enter_flux(kn);
KQ_UNLOCK(kq);
list->kl_unlock(list->kl_lockarg);
/*
* Activate existing knote and register tracking knotes with
* new process.
*
* First register a knote to get just the child notice. This
* must be a separate note from a potential NOTE_EXIT
* notification since both NOTE_CHILD and NOTE_EXIT are defined
* to use the data field (in conflicting ways).
*/
kev.ident = pid;
kev.filter = kn->kn_filter;
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT |
EV_FLAG2;
kev.fflags = kn->kn_sfflags;
kev.data = kn->kn_id; /* parent */
kev.udata = kn->kn_kevent.udata;/* preserve udata */
error = kqueue_register(kq, &kev, NULL, M_NOWAIT);
if (error)
kn->kn_fflags |= NOTE_TRACKERR;
/*
* Then register another knote to track other potential events
* from the new process.
*/
kev.ident = pid;
kev.filter = kn->kn_filter;
kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
kev.fflags = kn->kn_sfflags;
kev.data = kn->kn_id; /* parent */
kev.udata = kn->kn_kevent.udata;/* preserve udata */
error = kqueue_register(kq, &kev, NULL, M_NOWAIT);
if (error)
kn->kn_fflags |= NOTE_TRACKERR;
if (kn->kn_fop->f_event(kn, NOTE_FORK))
KNOTE_ACTIVATE(kn, 0);
list->kl_lock(list->kl_lockarg);
KQ_LOCK(kq);
kn_leave_flux(kn);
KQ_UNLOCK_FLUX(kq);
}
}
/*
* XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the
* interval timer support code.
*/
#define NOTE_TIMER_PRECMASK \
(NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS)
static sbintime_t
timer2sbintime(intptr_t data, int flags)
{
int64_t secs;
/*
* Macros for converting to the fractional second portion of an
* sbintime_t using 64bit multiplication to improve precision.
*/
#define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32)
#define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32)
#define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32)
switch (flags & NOTE_TIMER_PRECMASK) {
case NOTE_SECONDS:
#ifdef __LP64__
if (data > (SBT_MAX / SBT_1S))
return (SBT_MAX);
#endif
return ((sbintime_t)data << 32);
case NOTE_MSECONDS: /* FALLTHROUGH */
case 0:
if (data >= 1000) {
secs = data / 1000;
#ifdef __LP64__
if (secs > (SBT_MAX / SBT_1S))
return (SBT_MAX);
#endif
return (secs << 32 | MS_TO_SBT(data % 1000));
}
return (MS_TO_SBT(data));
case NOTE_USECONDS:
if (data >= 1000000) {
secs = data / 1000000;
#ifdef __LP64__
if (secs > (SBT_MAX / SBT_1S))
return (SBT_MAX);
#endif
return (secs << 32 | US_TO_SBT(data % 1000000));
}
return (US_TO_SBT(data));
case NOTE_NSECONDS:
if (data >= 1000000000) {
secs = data / 1000000000;
#ifdef __LP64__
if (secs > (SBT_MAX / SBT_1S))
return (SBT_MAX);
#endif
return (secs << 32 | US_TO_SBT(data % 1000000000));
}
return (NS_TO_SBT(data));
default:
break;
}
return (-1);
}
struct kq_timer_cb_data {
struct callout c;
sbintime_t next; /* next timer event fires at */
sbintime_t to; /* precalculated timer period, 0 for abs */
};
static void
filt_timerexpire(void *knx)
{
struct knote *kn;
struct kq_timer_cb_data *kc;
kn = knx;
kn->kn_data++;
KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */
if ((kn->kn_flags & EV_ONESHOT) != 0)
return;
kc = kn->kn_ptr.p_v;
if (kc->to == 0)
return;
kc->next += kc->to;
callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn,
PCPU_GET(cpuid), C_ABSOLUTE);
}
/*
* data contains amount of time to sleep
2004-08-12 18:06:21 +00:00
*/
static int
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
filt_timervalidate(struct knote *kn, sbintime_t *to)
{
struct bintime bt;
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
sbintime_t sbt;
if (kn->kn_sdata < 0)
return (EINVAL);
if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0)
kn->kn_sdata = 1;
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
/*
* The only fflags values supported are the timer unit
* (precision) and the absolute time indicator.
*/
if ((kn->kn_sfflags & ~(NOTE_TIMER_PRECMASK | NOTE_ABSTIME)) != 0)
return (EINVAL);
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
*to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags);
if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) {
getboottimebin(&bt);
sbt = bttosbt(bt);
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
*to -= sbt;
}
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
if (*to < 0)
return (EINVAL);
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
return (0);
}
static int
filt_timerattach(struct knote *kn)
{
struct kq_timer_cb_data *kc;
sbintime_t to;
unsigned int ncallouts;
int error;
error = filt_timervalidate(kn, &to);
if (error != 0)
return (error);
do {
ncallouts = kq_ncallouts;
if (ncallouts >= kq_calloutmax)
return (ENOMEM);
} while (!atomic_cmpset_int(&kq_ncallouts, ncallouts, ncallouts + 1));
if ((kn->kn_sfflags & NOTE_ABSTIME) == 0)
kn->kn_flags |= EV_CLEAR; /* automatically set */
kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */
kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK);
callout_init(&kc->c, 1);
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
filt_timerstart(kn, to);
return (0);
}
static void
filt_timerstart(struct knote *kn, sbintime_t to)
{
struct kq_timer_cb_data *kc;
kc = kn->kn_ptr.p_v;
if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) {
kc->next = to;
kc->to = 0;
} else {
kc->next = to + sbinuptime();
kc->to = to;
}
callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn,
PCPU_GET(cpuid), C_ABSOLUTE);
}
static void
filt_timerdetach(struct knote *kn)
{
struct kq_timer_cb_data *kc;
2018-05-19 05:06:18 +00:00
unsigned int old __unused;
kc = kn->kn_ptr.p_v;
callout_drain(&kc->c);
free(kc, M_KQUEUE);
2018-05-19 05:06:18 +00:00
old = atomic_fetchadd_int(&kq_ncallouts, -1);
KASSERT(old > 0, ("Number of callouts cannot become negative"));
kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */
}
Allow a EVFILT_TIMER kevent to be updated. If a timer is updated (re-added) with a different time period (specified in the .data field of the kevent), the new time period has no effect; the timer will not expire until the original time has elapsed. This violates the documented behavior as the kqueue(2) man page says (in part) "Re-adding an existing event will modify the parameters of the original event, and not result in a duplicate entry." This modification, adapted from a patch submitted by cem@ to PR214987, fixes the kqueue system to allow updating a timer entry. The kevent timer behavior is changed to: * When a timer is re-added, update the timer parameters to and re-start the timer using the new parameters. * Allow updating both active and already expired timers. * When the timer has already expired, dequeue any undelivered events and clear the count of expirations. All of these changes address the original PR and also bring the FreeBSD and macOS kevent timer behaviors into agreement. A few other changes were made along the way: * Update the kqueue(2) man page to reflect the new timer behavior. * Fix man page style issues in kqueue(2) diagnosed by igor. * Update the timer libkqueue system test to test for the updated timer behavior. * Fix the (test) libkqueue common.h file so that it includes config.h which defines various HAVE_* feature defines, before the #if tests for such variables in common.h. This enables the use of the actual err(3) family of functions. * Fix the usages of the err(3) functions in the tests for incorrect type of variables. Those were formerly undiagnosed due to the disablement of the err(3) functions (see previous bullet point). PR: 214987 Reported by: Brian Wellington <bwelling@xbill.org> Reviewed by: kib MFC after: 1 week Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D15778
2018-07-27 13:49:17 +00:00
static void
filt_timertouch(struct knote *kn, struct kevent *kev, u_long type)
{
struct kq_timer_cb_data *kc;
struct kqueue *kq;
sbintime_t to;
int error;
switch (type) {
case EVENT_REGISTER:
/* Handle re-added timers that update data/fflags */
if (kev->flags & EV_ADD) {
kc = kn->kn_ptr.p_v;
/* Drain any existing callout. */
callout_drain(&kc->c);
/* Throw away any existing undelivered record
* of the timer expiration. This is done under
* the presumption that if a process is
* re-adding this timer with new parameters,
* it is no longer interested in what may have
* happened under the old parameters. If it is
* interested, it can wait for the expiration,
* delete the old timer definition, and then
* add the new one.
*
* This has to be done while the kq is locked:
* - if enqueued, dequeue
* - make it no longer active
* - clear the count of expiration events
*/
kq = kn->kn_kq;
KQ_LOCK(kq);
if (kn->kn_status & KN_QUEUED)
knote_dequeue(kn);
kn->kn_status &= ~KN_ACTIVE;
kn->kn_data = 0;
KQ_UNLOCK(kq);
/* Reschedule timer based on new data/fflags */
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
error = filt_timervalidate(kn, &to);
if (error != 0) {
kn->kn_flags |= EV_ERROR;
kn->kn_data = error;
} else
filt_timerstart(kn, to);
}
break;
case EVENT_PROCESS:
*kev = kn->kn_kevent;
if (kn->kn_flags & EV_CLEAR) {
kn->kn_data = 0;
kn->kn_fflags = 0;
}
break;
default:
panic("filt_timertouch() - invalid type (%ld)", type);
break;
}
}
static int
filt_timer(struct knote *kn, long hint)
{
return (kn->kn_data != 0);
}
static int
filt_userattach(struct knote *kn)
{
/*
* EVFILT_USER knotes are not attached to anything in the kernel.
*/
kn->kn_hook = NULL;
if (kn->kn_fflags & NOTE_TRIGGER)
kn->kn_hookid = 1;
else
kn->kn_hookid = 0;
return (0);
}
static void
filt_userdetach(__unused struct knote *kn)
{
/*
* EVFILT_USER knotes are not attached to anything in the kernel.
*/
}
static int
filt_user(struct knote *kn, __unused long hint)
{
return (kn->kn_hookid);
}
static void
filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
{
u_int ffctrl;
switch (type) {
case EVENT_REGISTER:
if (kev->fflags & NOTE_TRIGGER)
kn->kn_hookid = 1;
ffctrl = kev->fflags & NOTE_FFCTRLMASK;
kev->fflags &= NOTE_FFLAGSMASK;
switch (ffctrl) {
case NOTE_FFNOP:
break;
case NOTE_FFAND:
kn->kn_sfflags &= kev->fflags;
break;
case NOTE_FFOR:
kn->kn_sfflags |= kev->fflags;
break;
case NOTE_FFCOPY:
kn->kn_sfflags = kev->fflags;
break;
default:
/* XXX Return error? */
break;
}
kn->kn_sdata = kev->data;
if (kev->flags & EV_CLEAR) {
kn->kn_hookid = 0;
kn->kn_data = 0;
kn->kn_fflags = 0;
}
break;
case EVENT_PROCESS:
*kev = kn->kn_kevent;
kev->fflags = kn->kn_sfflags;
kev->data = kn->kn_sdata;
if (kn->kn_flags & EV_CLEAR) {
kn->kn_hookid = 0;
kn->kn_data = 0;
kn->kn_fflags = 0;
}
break;
default:
panic("filt_usertouch() - invalid type (%ld)", type);
break;
}
}
int
sys_kqueue(struct thread *td, struct kqueue_args *uap)
{
return (kern_kqueue(td, 0, NULL));
}
static void
kqueue_init(struct kqueue *kq)
{
mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK);
TAILQ_INIT(&kq->kq_head);
knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
}
int
kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps)
{
struct filedesc *fdp;
struct kqueue *kq;
struct file *fp;
struct ucred *cred;
int fd, error;
fdp = td->td_proc->p_fd;
cred = td->td_ucred;
if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES)))
return (ENOMEM);
error = falloc_caps(td, &fp, &fd, flags, fcaps);
if (error != 0) {
chgkqcnt(cred->cr_ruidinfo, -1, 0);
return (error);
}
/* An extra reference on `fp' has been held for us by falloc(). */
kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
kqueue_init(kq);
kq->kq_fdp = fdp;
kq->kq_cred = crhold(cred);
FILEDESC_XLOCK(fdp);
TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
FILEDESC_XUNLOCK(fdp);
finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
fdrop(fp, td);
td->td_retval[0] = fd;
return (0);
}
struct g_kevent_args {
int fd;
void *changelist;
int nchanges;
void *eventlist;
int nevents;
const struct timespec *timeout;
};
int
sys_kevent(struct thread *td, struct kevent_args *uap)
{
struct kevent_copyops k_ops = {
.arg = uap,
.k_copyout = kevent_copyout,
.k_copyin = kevent_copyin,
.kevent_size = sizeof(struct kevent),
};
struct g_kevent_args gk_args = {
.fd = uap->fd,
.changelist = uap->changelist,
.nchanges = uap->nchanges,
.eventlist = uap->eventlist,
.nevents = uap->nevents,
.timeout = uap->timeout,
};
Decode kevent structures logged via ktrace(2) in kdump. - Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of structures. The structure name in the record payload is preceded by a size_t containing the size of the individual structures. Use this to replace the previous code that dumped the kevent arrays dumped for kevent(). kdump is now able to decode the kevent structures rather than dumping their contents via a hexdump. One change from before is that the 'changes' and 'events' arrays are not marked with separate 'read' and 'write' annotations in kdump output. Instead, the first array is the 'changes' array, and the second array (only present if kevent doesn't fail with an error) is the 'events' array. For kevent(), empty arrays are denoted by an entry with an array containing zero entries rather than no record. - Move kevent decoding tables from truss to libsysdecode. This adds three new functions to decode members of struct kevent: sysdecode_kevent_filter, sysdecode_kevent_flags, and sysdecode_kevent_fflags. kdump uses these helper functions to pretty-print kevent fields. - Move structure definitions for freebsd11 and freebsd32 kevent structures to <sys/event.h> so that they can be shared with userland. The 32-bit structures are only exposed if _WANT_KEVENT32 is defined. The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is defined. The 32-bit freebsd11 structure requires both. - Decode freebsd11 kevent structures in truss for the compat11.kevent() system call. - Log 32-bit kevent structures via ktrace for 32-bit compat kevent() system calls. - While here, constify the 'void *data' argument to ktrstruct(). Reviewed by: kib (earlier version) MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D12470
2017-11-25 04:49:12 +00:00
return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent"));
}
static int
kern_kevent_generic(struct thread *td, struct g_kevent_args *uap,
Decode kevent structures logged via ktrace(2) in kdump. - Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of structures. The structure name in the record payload is preceded by a size_t containing the size of the individual structures. Use this to replace the previous code that dumped the kevent arrays dumped for kevent(). kdump is now able to decode the kevent structures rather than dumping their contents via a hexdump. One change from before is that the 'changes' and 'events' arrays are not marked with separate 'read' and 'write' annotations in kdump output. Instead, the first array is the 'changes' array, and the second array (only present if kevent doesn't fail with an error) is the 'events' array. For kevent(), empty arrays are denoted by an entry with an array containing zero entries rather than no record. - Move kevent decoding tables from truss to libsysdecode. This adds three new functions to decode members of struct kevent: sysdecode_kevent_filter, sysdecode_kevent_flags, and sysdecode_kevent_fflags. kdump uses these helper functions to pretty-print kevent fields. - Move structure definitions for freebsd11 and freebsd32 kevent structures to <sys/event.h> so that they can be shared with userland. The 32-bit structures are only exposed if _WANT_KEVENT32 is defined. The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is defined. The 32-bit freebsd11 structure requires both. - Decode freebsd11 kevent structures in truss for the compat11.kevent() system call. - Log 32-bit kevent structures via ktrace for 32-bit compat kevent() system calls. - While here, constify the 'void *data' argument to ktrstruct(). Reviewed by: kib (earlier version) MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D12470
2017-11-25 04:49:12 +00:00
struct kevent_copyops *k_ops, const char *struct_name)
{
struct timespec ts, *tsp;
#ifdef KTRACE
Decode kevent structures logged via ktrace(2) in kdump. - Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of structures. The structure name in the record payload is preceded by a size_t containing the size of the individual structures. Use this to replace the previous code that dumped the kevent arrays dumped for kevent(). kdump is now able to decode the kevent structures rather than dumping their contents via a hexdump. One change from before is that the 'changes' and 'events' arrays are not marked with separate 'read' and 'write' annotations in kdump output. Instead, the first array is the 'changes' array, and the second array (only present if kevent doesn't fail with an error) is the 'events' array. For kevent(), empty arrays are denoted by an entry with an array containing zero entries rather than no record. - Move kevent decoding tables from truss to libsysdecode. This adds three new functions to decode members of struct kevent: sysdecode_kevent_filter, sysdecode_kevent_flags, and sysdecode_kevent_fflags. kdump uses these helper functions to pretty-print kevent fields. - Move structure definitions for freebsd11 and freebsd32 kevent structures to <sys/event.h> so that they can be shared with userland. The 32-bit structures are only exposed if _WANT_KEVENT32 is defined. The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is defined. The 32-bit freebsd11 structure requires both. - Decode freebsd11 kevent structures in truss for the compat11.kevent() system call. - Log 32-bit kevent structures via ktrace for 32-bit compat kevent() system calls. - While here, constify the 'void *data' argument to ktrstruct(). Reviewed by: kib (earlier version) MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D12470
2017-11-25 04:49:12 +00:00
struct kevent *eventlist = uap->eventlist;
#endif
Decode kevent structures logged via ktrace(2) in kdump. - Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of structures. The structure name in the record payload is preceded by a size_t containing the size of the individual structures. Use this to replace the previous code that dumped the kevent arrays dumped for kevent(). kdump is now able to decode the kevent structures rather than dumping their contents via a hexdump. One change from before is that the 'changes' and 'events' arrays are not marked with separate 'read' and 'write' annotations in kdump output. Instead, the first array is the 'changes' array, and the second array (only present if kevent doesn't fail with an error) is the 'events' array. For kevent(), empty arrays are denoted by an entry with an array containing zero entries rather than no record. - Move kevent decoding tables from truss to libsysdecode. This adds three new functions to decode members of struct kevent: sysdecode_kevent_filter, sysdecode_kevent_flags, and sysdecode_kevent_fflags. kdump uses these helper functions to pretty-print kevent fields. - Move structure definitions for freebsd11 and freebsd32 kevent structures to <sys/event.h> so that they can be shared with userland. The 32-bit structures are only exposed if _WANT_KEVENT32 is defined. The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is defined. The 32-bit freebsd11 structure requires both. - Decode freebsd11 kevent structures in truss for the compat11.kevent() system call. - Log 32-bit kevent structures via ktrace for 32-bit compat kevent() system calls. - While here, constify the 'void *data' argument to ktrstruct(). Reviewed by: kib (earlier version) MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D12470
2017-11-25 04:49:12 +00:00
int error;
if (uap->timeout != NULL) {
error = copyin(uap->timeout, &ts, sizeof(ts));
if (error)
return (error);
tsp = &ts;
} else
tsp = NULL;
#ifdef KTRACE
Decode kevent structures logged via ktrace(2) in kdump. - Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of structures. The structure name in the record payload is preceded by a size_t containing the size of the individual structures. Use this to replace the previous code that dumped the kevent arrays dumped for kevent(). kdump is now able to decode the kevent structures rather than dumping their contents via a hexdump. One change from before is that the 'changes' and 'events' arrays are not marked with separate 'read' and 'write' annotations in kdump output. Instead, the first array is the 'changes' array, and the second array (only present if kevent doesn't fail with an error) is the 'events' array. For kevent(), empty arrays are denoted by an entry with an array containing zero entries rather than no record. - Move kevent decoding tables from truss to libsysdecode. This adds three new functions to decode members of struct kevent: sysdecode_kevent_filter, sysdecode_kevent_flags, and sysdecode_kevent_fflags. kdump uses these helper functions to pretty-print kevent fields. - Move structure definitions for freebsd11 and freebsd32 kevent structures to <sys/event.h> so that they can be shared with userland. The 32-bit structures are only exposed if _WANT_KEVENT32 is defined. The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is defined. The 32-bit freebsd11 structure requires both. - Decode freebsd11 kevent structures in truss for the compat11.kevent() system call. - Log 32-bit kevent structures via ktrace for 32-bit compat kevent() system calls. - While here, constify the 'void *data' argument to ktrstruct(). Reviewed by: kib (earlier version) MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D12470
2017-11-25 04:49:12 +00:00
if (KTRPOINT(td, KTR_STRUCT_ARRAY))
ktrstructarray(struct_name, UIO_USERSPACE, uap->changelist,
uap->nchanges, k_ops->kevent_size);
#endif
error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
k_ops, tsp);
#ifdef KTRACE
Decode kevent structures logged via ktrace(2) in kdump. - Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of structures. The structure name in the record payload is preceded by a size_t containing the size of the individual structures. Use this to replace the previous code that dumped the kevent arrays dumped for kevent(). kdump is now able to decode the kevent structures rather than dumping their contents via a hexdump. One change from before is that the 'changes' and 'events' arrays are not marked with separate 'read' and 'write' annotations in kdump output. Instead, the first array is the 'changes' array, and the second array (only present if kevent doesn't fail with an error) is the 'events' array. For kevent(), empty arrays are denoted by an entry with an array containing zero entries rather than no record. - Move kevent decoding tables from truss to libsysdecode. This adds three new functions to decode members of struct kevent: sysdecode_kevent_filter, sysdecode_kevent_flags, and sysdecode_kevent_fflags. kdump uses these helper functions to pretty-print kevent fields. - Move structure definitions for freebsd11 and freebsd32 kevent structures to <sys/event.h> so that they can be shared with userland. The 32-bit structures are only exposed if _WANT_KEVENT32 is defined. The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is defined. The 32-bit freebsd11 structure requires both. - Decode freebsd11 kevent structures in truss for the compat11.kevent() system call. - Log 32-bit kevent structures via ktrace for 32-bit compat kevent() system calls. - While here, constify the 'void *data' argument to ktrstruct(). Reviewed by: kib (earlier version) MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D12470
2017-11-25 04:49:12 +00:00
if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY))
ktrstructarray(struct_name, UIO_USERSPACE, eventlist,
td->td_retval[0], k_ops->kevent_size);
#endif
return (error);
}
/*
* Copy 'count' items into the destination list pointed to by uap->eventlist.
*/
static int
kevent_copyout(void *arg, struct kevent *kevp, int count)
{
struct kevent_args *uap;
int error;
KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
uap = (struct kevent_args *)arg;
error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
if (error == 0)
uap->eventlist += count;
return (error);
}
/*
* Copy 'count' items from the list pointed to by uap->changelist.
*/
static int
kevent_copyin(void *arg, struct kevent *kevp, int count)
{
struct kevent_args *uap;
int error;
KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
uap = (struct kevent_args *)arg;
error = copyin(uap->changelist, kevp, count * sizeof *kevp);
if (error == 0)
uap->changelist += count;
return (error);
}
#ifdef COMPAT_FREEBSD11
static int
kevent11_copyout(void *arg, struct kevent *kevp, int count)
{
struct freebsd11_kevent_args *uap;
struct kevent_freebsd11 kev11;
int error, i;
KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
uap = (struct freebsd11_kevent_args *)arg;
for (i = 0; i < count; i++) {
kev11.ident = kevp->ident;
kev11.filter = kevp->filter;
kev11.flags = kevp->flags;
kev11.fflags = kevp->fflags;
kev11.data = kevp->data;
kev11.udata = kevp->udata;
error = copyout(&kev11, uap->eventlist, sizeof(kev11));
if (error != 0)
break;
uap->eventlist++;
kevp++;
}
return (error);
}
/*
* Copy 'count' items from the list pointed to by uap->changelist.
*/
static int
kevent11_copyin(void *arg, struct kevent *kevp, int count)
{
struct freebsd11_kevent_args *uap;
struct kevent_freebsd11 kev11;
int error, i;
KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
uap = (struct freebsd11_kevent_args *)arg;
for (i = 0; i < count; i++) {
error = copyin(uap->changelist, &kev11, sizeof(kev11));
if (error != 0)
break;
kevp->ident = kev11.ident;
kevp->filter = kev11.filter;
kevp->flags = kev11.flags;
kevp->fflags = kev11.fflags;
kevp->data = (uintptr_t)kev11.data;
kevp->udata = kev11.udata;
bzero(&kevp->ext, sizeof(kevp->ext));
uap->changelist++;
kevp++;
}
return (error);
}
int
freebsd11_kevent(struct thread *td, struct freebsd11_kevent_args *uap)
{
struct kevent_copyops k_ops = {
.arg = uap,
.k_copyout = kevent11_copyout,
.k_copyin = kevent11_copyin,
.kevent_size = sizeof(struct kevent_freebsd11),
};
struct g_kevent_args gk_args = {
.fd = uap->fd,
.changelist = uap->changelist,
.nchanges = uap->nchanges,
.eventlist = uap->eventlist,
.nevents = uap->nevents,
.timeout = uap->timeout,
};
Decode kevent structures logged via ktrace(2) in kdump. - Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of structures. The structure name in the record payload is preceded by a size_t containing the size of the individual structures. Use this to replace the previous code that dumped the kevent arrays dumped for kevent(). kdump is now able to decode the kevent structures rather than dumping their contents via a hexdump. One change from before is that the 'changes' and 'events' arrays are not marked with separate 'read' and 'write' annotations in kdump output. Instead, the first array is the 'changes' array, and the second array (only present if kevent doesn't fail with an error) is the 'events' array. For kevent(), empty arrays are denoted by an entry with an array containing zero entries rather than no record. - Move kevent decoding tables from truss to libsysdecode. This adds three new functions to decode members of struct kevent: sysdecode_kevent_filter, sysdecode_kevent_flags, and sysdecode_kevent_fflags. kdump uses these helper functions to pretty-print kevent fields. - Move structure definitions for freebsd11 and freebsd32 kevent structures to <sys/event.h> so that they can be shared with userland. The 32-bit structures are only exposed if _WANT_KEVENT32 is defined. The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is defined. The 32-bit freebsd11 structure requires both. - Decode freebsd11 kevent structures in truss for the compat11.kevent() system call. - Log 32-bit kevent structures via ktrace for 32-bit compat kevent() system calls. - While here, constify the 'void *data' argument to ktrstruct(). Reviewed by: kib (earlier version) MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D12470
2017-11-25 04:49:12 +00:00
return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent_freebsd11"));
}
#endif
int
kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
struct kevent_copyops *k_ops, const struct timespec *timeout)
{
cap_rights_t rights;
struct file *fp;
int error;
cap_rights_init(&rights);
if (nchanges > 0)
cap_rights_set(&rights, CAP_KQUEUE_CHANGE);
if (nevents > 0)
cap_rights_set(&rights, CAP_KQUEUE_EVENT);
error = fget(td, fd, &rights, &fp);
if (error != 0)
return (error);
error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout);
fdrop(fp, td);
return (error);
}
static int
kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents,
struct kevent_copyops *k_ops, const struct timespec *timeout)
{
struct kevent keva[KQ_NEVENTS];
struct kevent *kevp, *changes;
int i, n, nerrors, error;
nerrors = 0;
while (nchanges > 0) {
n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
error = k_ops->k_copyin(k_ops->arg, keva, n);
if (error)
return (error);
changes = keva;
for (i = 0; i < n; i++) {
kevp = &changes[i];
if (!kevp->filter)
continue;
kevp->flags &= ~EV_SYSFLAGS;
error = kqueue_register(kq, kevp, td, M_WAITOK);
if (error || (kevp->flags & EV_RECEIPT)) {
if (nevents == 0)
return (error);
kevp->flags = EV_ERROR;
kevp->data = error;
(void)k_ops->k_copyout(k_ops->arg, kevp, 1);
nevents--;
nerrors++;
}
}
nchanges -= n;
}
if (nerrors) {
td->td_retval[0] = nerrors;
return (0);
}
return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td));
}
int
kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents,
struct kevent_copyops *k_ops, const struct timespec *timeout)
{
struct kqueue *kq;
int error;
error = kqueue_acquire(fp, &kq);
if (error != 0)
return (error);
error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout);
kqueue_release(kq, 0);
return (error);
}
/*
* Performs a kevent() call on a temporarily created kqueue. This can be
* used to perform one-shot polling, similar to poll() and select().
*/
int
kern_kevent_anonymous(struct thread *td, int nevents,
struct kevent_copyops *k_ops)
{
struct kqueue kq = {};
int error;
kqueue_init(&kq);
kq.kq_refcnt = 1;
error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL);
kqueue_drain(&kq, td);
kqueue_destroy(&kq);
return (error);
}
int
kqueue_add_filteropts(int filt, struct filterops *filtops)
{
int error;
error = 0;
if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
printf(
"trying to add a filterop that is out of range: %d is beyond %d\n",
~filt, EVFILT_SYSCOUNT);
return EINVAL;
}
mtx_lock(&filterops_lock);
if (sysfilt_ops[~filt].for_fop != &null_filtops &&
sysfilt_ops[~filt].for_fop != NULL)
error = EEXIST;
else {
sysfilt_ops[~filt].for_fop = filtops;
sysfilt_ops[~filt].for_refcnt = 0;
}
mtx_unlock(&filterops_lock);
return (error);
}
int
kqueue_del_filteropts(int filt)
{
int error;
error = 0;
if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
return EINVAL;
mtx_lock(&filterops_lock);
if (sysfilt_ops[~filt].for_fop == &null_filtops ||
sysfilt_ops[~filt].for_fop == NULL)
error = EINVAL;
else if (sysfilt_ops[~filt].for_refcnt != 0)
error = EBUSY;
else {
sysfilt_ops[~filt].for_fop = &null_filtops;
sysfilt_ops[~filt].for_refcnt = 0;
}
mtx_unlock(&filterops_lock);
return error;
}
static struct filterops *
kqueue_fo_find(int filt)
{
if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
return NULL;
if (sysfilt_ops[~filt].for_nolock)
return sysfilt_ops[~filt].for_fop;
mtx_lock(&filterops_lock);
sysfilt_ops[~filt].for_refcnt++;
if (sysfilt_ops[~filt].for_fop == NULL)
sysfilt_ops[~filt].for_fop = &null_filtops;
mtx_unlock(&filterops_lock);
return sysfilt_ops[~filt].for_fop;
}
static void
kqueue_fo_release(int filt)
{
if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
return;
if (sysfilt_ops[~filt].for_nolock)
return;
mtx_lock(&filterops_lock);
KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
("filter object refcount not valid on release"));
sysfilt_ops[~filt].for_refcnt--;
mtx_unlock(&filterops_lock);
}
/*
* A ref to kq (obtained via kqueue_acquire) must be held.
*/
static int
kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td,
int mflag)
{
struct filterops *fops;
struct file *fp;
struct knote *kn, *tkn;
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
struct knlist *knl;
int error, filt, event;
int haskqglobal, filedesc_unlock;
if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE))
return (EINVAL);
fp = NULL;
kn = NULL;
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
knl = NULL;
error = 0;
haskqglobal = 0;
filedesc_unlock = 0;
filt = kev->filter;
fops = kqueue_fo_find(filt);
if (fops == NULL)
return EINVAL;
if (kev->flags & EV_ADD) {
/*
* Prevent waiting with locks. Non-sleepable
* allocation failures are handled in the loop, only
* if the spare knote appears to be actually required.
*/
tkn = knote_alloc(mflag);
} else {
tkn = NULL;
}
findkn:
if (fops->f_isfd) {
KASSERT(td != NULL, ("td is NULL"));
if (kev->ident > INT_MAX)
error = EBADF;
else
error = fget(td, kev->ident, &cap_event_rights, &fp);
if (error)
goto done;
if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
kev->ident, M_NOWAIT) != 0) {
/* try again */
fdrop(fp, td);
fp = NULL;
error = kqueue_expand(kq, fops, kev->ident, mflag);
if (error)
goto done;
goto findkn;
}
if (fp->f_type == DTYPE_KQUEUE) {
/*
* If we add some intelligence about what we are doing,
* we should be able to support events on ourselves.
* We need to know when we are doing this to prevent
* getting both the knlist lock and the kq lock since
* they are the same thing.
*/
if (fp->f_data == kq) {
error = EINVAL;
goto done;
}
/*
* Pre-lock the filedesc before the global
* lock mutex, see the comment in
* kqueue_close().
*/
FILEDESC_XLOCK(td->td_proc->p_fd);
filedesc_unlock = 1;
KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
}
KQ_LOCK(kq);
if (kev->ident < kq->kq_knlistsize) {
SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
if (kev->filter == kn->kn_filter)
break;
}
} else {
if ((kev->flags & EV_ADD) == EV_ADD) {
error = kqueue_expand(kq, fops, kev->ident, mflag);
if (error != 0)
goto done;
}
KQ_LOCK(kq);
/*
* If possible, find an existing knote to use for this kevent.
*/
if (kev->filter == EVFILT_PROC &&
(kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) {
/* This is an internal creation of a process tracking
* note. Don't attempt to coalesce this with an
* existing note.
*/
;
} else if (kq->kq_knhashmask != 0) {
struct klist *list;
2004-08-13 07:38:58 +00:00
list = &kq->kq_knhash[
KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
SLIST_FOREACH(kn, list, kn_link)
if (kev->ident == kn->kn_id &&
kev->filter == kn->kn_filter)
break;
}
}
/* knote is in the process of changing, wait for it to stabilize. */
if (kn != NULL && kn_in_flux(kn)) {
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
if (filedesc_unlock) {
FILEDESC_XUNLOCK(td->td_proc->p_fd);
filedesc_unlock = 0;
}
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
if (fp != NULL) {
fdrop(fp, td);
fp = NULL;
}
goto findkn;
}
/*
* kn now contains the matching knote, or NULL if no match
*/
if (kn == NULL) {
if (kev->flags & EV_ADD) {
kn = tkn;
tkn = NULL;
if (kn == NULL) {
KQ_UNLOCK(kq);
error = ENOMEM;
goto done;
}
kn->kn_fp = fp;
kn->kn_kq = kq;
kn->kn_fop = fops;
/*
* apply reference counts to knote structure, and
* do not release it at the end of this routine.
*/
fops = NULL;
fp = NULL;
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
kev->fflags = 0;
kev->data = 0;
kn->kn_kevent = *kev;
kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT);
kn->kn_status = KN_DETACHED;
if ((kev->flags & EV_DISABLE) != 0)
kn->kn_status |= KN_DISABLED;
kn_enter_flux(kn);
error = knote_attach(kn, kq);
KQ_UNLOCK(kq);
if (error != 0) {
tkn = kn;
goto done;
}
if ((error = kn->kn_fop->f_attach(kn)) != 0) {
knote_drop_detached(kn, td);
goto done;
}
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
knl = kn_list_lock(kn);
goto done_ev_add;
} else {
/* No matching knote and the EV_ADD flag is not set. */
KQ_UNLOCK(kq);
error = ENOENT;
goto done;
}
}
if (kev->flags & EV_DELETE) {
kn_enter_flux(kn);
KQ_UNLOCK(kq);
knote_drop(kn, td);
goto done;
}
if (kev->flags & EV_FORCEONESHOT) {
kn->kn_flags |= EV_ONESHOT;
KNOTE_ACTIVATE(kn, 1);
}
if ((kev->flags & EV_ENABLE) != 0)
kn->kn_status &= ~KN_DISABLED;
else if ((kev->flags & EV_DISABLE) != 0)
kn->kn_status |= KN_DISABLED;
/*
* The user may change some filter values after the initial EV_ADD,
* but doing so will not reset any filter which has already been
* triggered.
*/
kn->kn_status |= KN_SCAN;
kn_enter_flux(kn);
KQ_UNLOCK(kq);
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
knl = kn_list_lock(kn);
kn->kn_kevent.udata = kev->udata;
if (!fops->f_isfd && fops->f_touch != NULL) {
fops->f_touch(kn, kev, EVENT_REGISTER);
} else {
kn->kn_sfflags = kev->fflags;
kn->kn_sdata = kev->data;
}
done_ev_add:
/*
* We can get here with kn->kn_knlist == NULL. This can happen when
* the initial attach event decides that the event is "completed"
* already, e.g., filt_procattach() is called on a zombie process. It
* will call filt_proc() which will remove it from the list, and NULL
* kn_knlist.
*
* KN_DISABLED will be stable while the knote is in flux, so the
* unlocked read will not race with an update.
*/
if ((kn->kn_status & KN_DISABLED) == 0)
event = kn->kn_fop->f_event(kn, 0);
else
event = 0;
KQ_LOCK(kq);
if (event)
kn->kn_status |= KN_ACTIVE;
if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) ==
KN_ACTIVE)
knote_enqueue(kn);
kn->kn_status &= ~KN_SCAN;
kn_leave_flux(kn);
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
kn_list_unlock(knl);
KQ_UNLOCK_FLUX(kq);
done:
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
if (filedesc_unlock)
FILEDESC_XUNLOCK(td->td_proc->p_fd);
if (fp != NULL)
fdrop(fp, td);
knote_free(tkn);
if (fops != NULL)
kqueue_fo_release(filt);
return (error);
}
static int
kqueue_acquire(struct file *fp, struct kqueue **kqp)
{
int error;
struct kqueue *kq;
error = 0;
kq = fp->f_data;
if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
return (EBADF);
*kqp = kq;
KQ_LOCK(kq);
if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
KQ_UNLOCK(kq);
return (EBADF);
}
kq->kq_refcnt++;
KQ_UNLOCK(kq);
return error;
}
static void
kqueue_release(struct kqueue *kq, int locked)
{
if (locked)
KQ_OWNED(kq);
else
KQ_LOCK(kq);
kq->kq_refcnt--;
if (kq->kq_refcnt == 1)
wakeup(&kq->kq_refcnt);
if (!locked)
KQ_UNLOCK(kq);
}
static void
kqueue_schedtask(struct kqueue *kq)
{
KQ_OWNED(kq);
KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
("scheduling kqueue task while draining"));
if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task);
kq->kq_state |= KQ_TASKSCHED;
}
}
/*
* Expand the kq to make sure we have storage for fops/ident pair.
*
* Return 0 on success (or no work necessary), return errno on failure.
*/
static int
kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident,
int mflag)
{
struct klist *list, *tmp_knhash, *to_free;
u_long tmp_knhashmask;
int error, fd, size;
KQ_NOTOWNED(kq);
error = 0;
to_free = NULL;
if (fops->f_isfd) {
fd = ident;
if (kq->kq_knlistsize <= fd) {
size = kq->kq_knlistsize;
while (size <= fd)
size += KQEXTENT;
list = malloc(size * sizeof(*list), M_KQUEUE, mflag);
if (list == NULL)
return ENOMEM;
KQ_LOCK(kq);
if ((kq->kq_state & KQ_CLOSING) != 0) {
to_free = list;
error = EBADF;
} else if (kq->kq_knlistsize > fd) {
to_free = list;
} else {
if (kq->kq_knlist != NULL) {
bcopy(kq->kq_knlist, list,
kq->kq_knlistsize * sizeof(*list));
to_free = kq->kq_knlist;
kq->kq_knlist = NULL;
}
bzero((caddr_t)list +
kq->kq_knlistsize * sizeof(*list),
(size - kq->kq_knlistsize) * sizeof(*list));
kq->kq_knlistsize = size;
kq->kq_knlist = list;
}
KQ_UNLOCK(kq);
}
} else {
if (kq->kq_knhashmask == 0) {
tmp_knhash = hashinit_flags(KN_HASHSIZE, M_KQUEUE,
&tmp_knhashmask, (mflag & M_WAITOK) != 0 ?
HASH_WAITOK : HASH_NOWAIT);
if (tmp_knhash == NULL)
return (ENOMEM);
KQ_LOCK(kq);
if ((kq->kq_state & KQ_CLOSING) != 0) {
to_free = tmp_knhash;
error = EBADF;
} else if (kq->kq_knhashmask == 0) {
kq->kq_knhash = tmp_knhash;
kq->kq_knhashmask = tmp_knhashmask;
} else {
to_free = tmp_knhash;
}
KQ_UNLOCK(kq);
}
}
free(to_free, M_KQUEUE);
KQ_NOTOWNED(kq);
return (error);
}
static void
kqueue_task(void *arg, int pending)
{
struct kqueue *kq;
int haskqglobal;
haskqglobal = 0;
kq = arg;
KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
KQ_LOCK(kq);
KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
kq->kq_state &= ~KQ_TASKSCHED;
if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
wakeup(&kq->kq_state);
}
KQ_UNLOCK(kq);
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
}
/*
* Scan, update kn_data (if not ONESHOT), and copyout triggered events.
* We treat KN_MARKER knotes as if they are in flux.
*/
static int
kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
const struct timespec *tsp, struct kevent *keva, struct thread *td)
{
struct kevent *kevp;
struct knote *kn, *marker;
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
struct knlist *knl;
sbintime_t asbt, rsbt;
int count, error, haskqglobal, influx, nkev, touch;
count = maxevents;
nkev = 0;
error = 0;
haskqglobal = 0;
if (maxevents == 0)
goto done_nl;
rsbt = 0;
if (tsp != NULL) {
if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 ||
tsp->tv_nsec >= 1000000000) {
error = EINVAL;
goto done_nl;
}
if (timespecisset(tsp)) {
if (tsp->tv_sec <= INT32_MAX) {
rsbt = tstosbt(*tsp);
if (TIMESEL(&asbt, rsbt))
asbt += tc_tick_sbt;
if (asbt <= SBT_MAX - rsbt)
asbt += rsbt;
else
asbt = 0;
rsbt >>= tc_precexp;
} else
asbt = 0;
} else
asbt = -1;
} else
asbt = 0;
marker = knote_alloc(M_WAITOK);
marker->kn_status = KN_MARKER;
KQ_LOCK(kq);
retry:
kevp = keva;
if (kq->kq_count == 0) {
if (asbt == -1) {
error = EWOULDBLOCK;
} else {
kq->kq_state |= KQ_SLEEP;
error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH,
"kqread", asbt, rsbt, C_ABSOLUTE);
}
if (error == 0)
goto retry;
/* don't restart after signals... */
if (error == ERESTART)
error = EINTR;
else if (error == EWOULDBLOCK)
error = 0;
goto done;
}
TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
influx = 0;
while (count) {
KQ_OWNED(kq);
kn = TAILQ_FIRST(&kq->kq_head);
if ((kn->kn_status == KN_MARKER && kn != marker) ||
kn_in_flux(kn)) {
if (influx) {
influx = 0;
KQ_FLUX_WAKEUP(kq);
}
kq->kq_state |= KQ_FLUXWAIT;
error = msleep(kq, &kq->kq_lock, PSOCK,
"kqflxwt", 0);
continue;
}
TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
kn->kn_status &= ~KN_QUEUED;
kq->kq_count--;
continue;
}
if (kn == marker) {
KQ_FLUX_WAKEUP(kq);
if (count == maxevents)
goto retry;
goto done;
}
KASSERT(!kn_in_flux(kn),
("knote %p is unexpectedly in flux", kn));
if ((kn->kn_flags & EV_DROP) == EV_DROP) {
kn->kn_status &= ~KN_QUEUED;
kn_enter_flux(kn);
kq->kq_count--;
KQ_UNLOCK(kq);
/*
* We don't need to lock the list since we've
* marked it as in flux.
*/
knote_drop(kn, td);
KQ_LOCK(kq);
continue;
} else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
kn->kn_status &= ~KN_QUEUED;
kn_enter_flux(kn);
kq->kq_count--;
KQ_UNLOCK(kq);
/*
* We don't need to lock the list since we've
* marked the knote as being in flux.
*/
*kevp = kn->kn_kevent;
knote_drop(kn, td);
KQ_LOCK(kq);
kn = NULL;
} else {
kn->kn_status |= KN_SCAN;
kn_enter_flux(kn);
KQ_UNLOCK(kq);
if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
knl = kn_list_lock(kn);
if (kn->kn_fop->f_event(kn, 0) == 0) {
KQ_LOCK(kq);
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE |
KN_SCAN);
kn_leave_flux(kn);
kq->kq_count--;
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
kn_list_unlock(knl);
influx = 1;
continue;
}
touch = (!kn->kn_fop->f_isfd &&
kn->kn_fop->f_touch != NULL);
if (touch)
kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
else
*kevp = kn->kn_kevent;
KQ_LOCK(kq);
KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) {
/*
* Manually clear knotes who weren't
* 'touch'ed.
*/
if (touch == 0 && kn->kn_flags & EV_CLEAR) {
kn->kn_data = 0;
kn->kn_fflags = 0;
}
if (kn->kn_flags & EV_DISPATCH)
kn->kn_status |= KN_DISABLED;
kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
kq->kq_count--;
} else
TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
kn->kn_status &= ~KN_SCAN;
kn_leave_flux(kn);
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
kn_list_unlock(knl);
influx = 1;
}
/* we are returning a copy to the user */
kevp++;
nkev++;
count--;
if (nkev == KQ_NEVENTS) {
influx = 0;
KQ_UNLOCK_FLUX(kq);
error = k_ops->k_copyout(k_ops->arg, keva, nkev);
nkev = 0;
kevp = keva;
KQ_LOCK(kq);
if (error)
break;
}
}
TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
done:
KQ_OWNED(kq);
KQ_UNLOCK_FLUX(kq);
knote_free(marker);
done_nl:
KQ_NOTOWNED(kq);
if (nkev != 0)
error = k_ops->k_copyout(k_ops->arg, keva, nkev);
td->td_retval[0] = maxevents - count;
return (error);
}
/*ARGSUSED*/
static int
kqueue_ioctl(struct file *fp, u_long cmd, void *data,
struct ucred *active_cred, struct thread *td)
{
/*
* Enabling sigio causes two major problems:
* 1) infinite recursion:
* Synopsys: kevent is being used to track signals and have FIOASYNC
* set. On receipt of a signal this will cause a kqueue to recurse
* into itself over and over. Sending the sigio causes the kqueue
* to become ready, which in turn posts sigio again, forever.
* Solution: this can be solved by setting a flag in the kqueue that
* we have a SIGIO in progress.
* 2) locking problems:
* Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
* us above the proc and pgrp locks.
* Solution: Post a signal using an async mechanism, being sure to
* record a generation count in the delivery so that we do not deliver
* a signal to the wrong process.
*
* Note, these two mechanisms are somewhat mutually exclusive!
*/
#if 0
struct kqueue *kq;
kq = fp->f_data;
switch (cmd) {
case FIOASYNC:
if (*(int *)data) {
kq->kq_state |= KQ_ASYNC;
} else {
kq->kq_state &= ~KQ_ASYNC;
}
return (0);
case FIOSETOWN:
return (fsetown(*(int *)data, &kq->kq_sigio));
case FIOGETOWN:
*(int *)data = fgetown(&kq->kq_sigio);
return (0);
}
#endif
return (ENOTTY);
}
/*ARGSUSED*/
static int
Make similar changes to fo_stat() and fo_poll() as made earlier to fo_read() and fo_write(): explicitly use the cred argument to fo_poll() as "active_cred" using the passed file descriptor's f_cred reference to provide access to the file credential. Add an active_cred argument to fo_stat() so that implementers have access to the active credential as well as the file credential. Generally modify callers of fo_stat() to pass in td->td_ucred rather than fp->f_cred, which was redundantly provided via the fp argument. This set of modifications also permits threads to perform these operations on behalf of another thread without modifying their credential. Trickle this change down into fo_stat/poll() implementations: - badfo_poll(), badfo_stat(): modify/add arguments. - kqueue_poll(), kqueue_stat(): modify arguments. - pipe_poll(), pipe_stat(): modify/add arguments, pass active_cred to MAC checks rather than td->td_ucred. - soo_poll(), soo_stat(): modify/add arguments, pass fp->f_cred rather than cred to pru_sopoll() to maintain current semantics. - sopoll(): moidfy arguments. - vn_poll(), vn_statfile(): modify/add arguments, pass new arguments to vn_stat(). Pass active_cred to MAC and fp->f_cred to VOP_POLL() to maintian current semantics. - vn_close(): rename cred to file_cred to reflect reality while I'm here. - vn_stat(): Add active_cred and file_cred arguments to vn_stat() and consumers so that this distinction is maintained at the VFS as well as 'struct file' layer. Pass active_cred instead of td->td_ucred to MAC and to VOP_GETATTR() to maintain current semantics. - fifofs: modify the creation of a "filetemp" so that the file credential is properly initialized and can be used in the socket code if desired. Pass ap->a_td->td_ucred as the active credential to soo_poll(). If we teach the vnop interface about the distinction between file and active credentials, we would use the active credential here. Note that current inconsistent passing of active_cred vs. file_cred to VOP's is maintained. It's not clear why GETATTR would be authorized using active_cred while POLL would be authorized using file_cred at the file system level. Obtained from: TrustedBSD Project Sponsored by: DARPA, NAI Labs
2002-08-16 12:52:03 +00:00
kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
struct thread *td)
{
struct kqueue *kq;
int revents = 0;
int error;
if ((error = kqueue_acquire(fp, &kq)))
return POLLERR;
KQ_LOCK(kq);
if (events & (POLLIN | POLLRDNORM)) {
if (kq->kq_count) {
revents |= events & (POLLIN | POLLRDNORM);
} else {
selrecord(td, &kq->kq_sel);
if (SEL_WAITING(&kq->kq_sel))
kq->kq_state |= KQ_SEL;
}
}
kqueue_release(kq, 1);
KQ_UNLOCK(kq);
return (revents);
}
/*ARGSUSED*/
static int
Make similar changes to fo_stat() and fo_poll() as made earlier to fo_read() and fo_write(): explicitly use the cred argument to fo_poll() as "active_cred" using the passed file descriptor's f_cred reference to provide access to the file credential. Add an active_cred argument to fo_stat() so that implementers have access to the active credential as well as the file credential. Generally modify callers of fo_stat() to pass in td->td_ucred rather than fp->f_cred, which was redundantly provided via the fp argument. This set of modifications also permits threads to perform these operations on behalf of another thread without modifying their credential. Trickle this change down into fo_stat/poll() implementations: - badfo_poll(), badfo_stat(): modify/add arguments. - kqueue_poll(), kqueue_stat(): modify arguments. - pipe_poll(), pipe_stat(): modify/add arguments, pass active_cred to MAC checks rather than td->td_ucred. - soo_poll(), soo_stat(): modify/add arguments, pass fp->f_cred rather than cred to pru_sopoll() to maintain current semantics. - sopoll(): moidfy arguments. - vn_poll(), vn_statfile(): modify/add arguments, pass new arguments to vn_stat(). Pass active_cred to MAC and fp->f_cred to VOP_POLL() to maintian current semantics. - vn_close(): rename cred to file_cred to reflect reality while I'm here. - vn_stat(): Add active_cred and file_cred arguments to vn_stat() and consumers so that this distinction is maintained at the VFS as well as 'struct file' layer. Pass active_cred instead of td->td_ucred to MAC and to VOP_GETATTR() to maintain current semantics. - fifofs: modify the creation of a "filetemp" so that the file credential is properly initialized and can be used in the socket code if desired. Pass ap->a_td->td_ucred as the active credential to soo_poll(). If we teach the vnop interface about the distinction between file and active credentials, we would use the active credential here. Note that current inconsistent passing of active_cred vs. file_cred to VOP's is maintained. It's not clear why GETATTR would be authorized using active_cred while POLL would be authorized using file_cred at the file system level. Obtained from: TrustedBSD Project Sponsored by: DARPA, NAI Labs
2002-08-16 12:52:03 +00:00
kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
struct thread *td)
{
bzero((void *)st, sizeof *st);
/*
* We no longer return kq_count because the unlocked value is useless.
* If you spent all this time getting the count, why not spend your
* syscall better by calling kevent?
*
* XXX - This is needed for libc_r.
*/
st->st_mode = S_IFIFO;
return (0);
}
static void
kqueue_drain(struct kqueue *kq, struct thread *td)
{
struct knote *kn;
int i;
KQ_LOCK(kq);
KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
("kqueue already closing"));
kq->kq_state |= KQ_CLOSING;
if (kq->kq_refcnt > 1)
msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
KASSERT(knlist_empty(&kq->kq_sel.si_note),
("kqueue's knlist not empty"));
for (i = 0; i < kq->kq_knlistsize; i++) {
while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
if (kn_in_flux(kn)) {
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
continue;
}
kn_enter_flux(kn);
KQ_UNLOCK(kq);
knote_drop(kn, td);
KQ_LOCK(kq);
}
}
if (kq->kq_knhashmask != 0) {
for (i = 0; i <= kq->kq_knhashmask; i++) {
while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
if (kn_in_flux(kn)) {
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK,
"kqclo2", 0);
continue;
}
kn_enter_flux(kn);
KQ_UNLOCK(kq);
knote_drop(kn, td);
KQ_LOCK(kq);
}
}
}
if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
kq->kq_state |= KQ_TASKDRAIN;
msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
}
if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
selwakeuppri(&kq->kq_sel, PSOCK);
if (!SEL_WAITING(&kq->kq_sel))
kq->kq_state &= ~KQ_SEL;
}
KQ_UNLOCK(kq);
}
static void
kqueue_destroy(struct kqueue *kq)
{
KASSERT(kq->kq_fdp == NULL,
("kqueue still attached to a file descriptor"));
seldrain(&kq->kq_sel);
knlist_destroy(&kq->kq_sel.si_note);
mtx_destroy(&kq->kq_lock);
if (kq->kq_knhash != NULL)
free(kq->kq_knhash, M_KQUEUE);
if (kq->kq_knlist != NULL)
free(kq->kq_knlist, M_KQUEUE);
funsetown(&kq->kq_sigio);
}
/*ARGSUSED*/
static int
kqueue_close(struct file *fp, struct thread *td)
{
struct kqueue *kq = fp->f_data;
struct filedesc *fdp;
int error;
int filedesc_unlock;
if ((error = kqueue_acquire(fp, &kq)))
return error;
kqueue_drain(kq, td);
/*
* We could be called due to the knote_drop() doing fdrop(),
* called from kqueue_register(). In this case the global
* lock is owned, and filedesc sx is locked before, to not
* take the sleepable lock after non-sleepable.
*/
fdp = kq->kq_fdp;
kq->kq_fdp = NULL;
if (!sx_xlocked(FILEDESC_LOCK(fdp))) {
FILEDESC_XLOCK(fdp);
filedesc_unlock = 1;
} else
filedesc_unlock = 0;
TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list);
if (filedesc_unlock)
FILEDESC_XUNLOCK(fdp);
kqueue_destroy(kq);
chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0);
crfree(kq->kq_cred);
free(kq, M_KQUEUE);
fp->f_data = NULL;
return (0);
}
static int
kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
{
kif->kf_type = KF_TYPE_KQUEUE;
return (0);
}
static void
kqueue_wakeup(struct kqueue *kq)
{
KQ_OWNED(kq);
if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
kq->kq_state &= ~KQ_SLEEP;
wakeup(kq);
}
if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
selwakeuppri(&kq->kq_sel, PSOCK);
if (!SEL_WAITING(&kq->kq_sel))
kq->kq_state &= ~KQ_SEL;
}
if (!knlist_empty(&kq->kq_sel.si_note))
kqueue_schedtask(kq);
if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
pgsigio(&kq->kq_sigio, SIGIO, 0);
}
}
/*
* Walk down a list of knotes, activating them if their event has triggered.
*
* There is a possibility to optimize in the case of one kq watching another.
* Instead of scheduling a task to wake it up, you could pass enough state
* down the chain to make up the parent kqueue. Make this code functional
* first.
*/
void
knote(struct knlist *list, long hint, int lockflags)
{
struct kqueue *kq;
struct knote *kn, *tkn;
int error;
if (list == NULL)
return;
KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
if ((lockflags & KNF_LISTLOCKED) == 0)
list->kl_lock(list->kl_lockarg);
/*
* If we unlock the list lock (and enter influx), we can
* eliminate the kqueue scheduling, but this will introduce
* four lock/unlock's for each knote to test. Also, marker
* would be needed to keep iteration position, since filters
* or other threads could remove events.
*/
SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) {
kq = kn->kn_kq;
KQ_LOCK(kq);
if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) {
/*
* Do not process the influx notes, except for
* the influx coming from the kq unlock in the
* kqueue_scan(). In the later case, we do
* not interfere with the scan, since the code
* fragment in kqueue_scan() locks the knlist,
* and cannot proceed until we finished.
*/
KQ_UNLOCK(kq);
} else if ((lockflags & KNF_NOKQLOCK) != 0) {
kn_enter_flux(kn);
KQ_UNLOCK(kq);
error = kn->kn_fop->f_event(kn, hint);
KQ_LOCK(kq);
kn_leave_flux(kn);
if (error)
KNOTE_ACTIVATE(kn, 1);
KQ_UNLOCK_FLUX(kq);
} else {
if (kn->kn_fop->f_event(kn, hint))
KNOTE_ACTIVATE(kn, 1);
KQ_UNLOCK(kq);
}
}
if ((lockflags & KNF_LISTLOCKED) == 0)
list->kl_unlock(list->kl_lockarg);
}
/*
* add a knote to a knlist
*/
void
knlist_add(struct knlist *knl, struct knote *kn, int islocked)
{
KNL_ASSERT_LOCK(knl, islocked);
KQ_NOTOWNED(kn->kn_kq);
KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn));
KASSERT((kn->kn_status & KN_DETACHED) != 0,
("knote %p was not detached", kn));
if (!islocked)
knl->kl_lock(knl->kl_lockarg);
SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
if (!islocked)
knl->kl_unlock(knl->kl_lockarg);
KQ_LOCK(kn->kn_kq);
kn->kn_knlist = knl;
kn->kn_status &= ~KN_DETACHED;
KQ_UNLOCK(kn->kn_kq);
}
static void
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked,
int kqislocked)
{
KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked"));
KNL_ASSERT_LOCK(knl, knlislocked);
mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn));
KASSERT((kn->kn_status & KN_DETACHED) == 0,
("knote %p was already detached", kn));
if (!knlislocked)
knl->kl_lock(knl->kl_lockarg);
SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
kn->kn_knlist = NULL;
if (!knlislocked)
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
kn_list_unlock(knl);
if (!kqislocked)
KQ_LOCK(kn->kn_kq);
kn->kn_status |= KN_DETACHED;
if (!kqislocked)
KQ_UNLOCK(kn->kn_kq);
}
/*
* remove knote from the specified knlist
*/
void
knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
{
knlist_remove_kq(knl, kn, islocked, 0);
}
int
knlist_empty(struct knlist *knl)
{
KNL_ASSERT_LOCKED(knl);
return (SLIST_EMPTY(&knl->kl_list));
}
static struct mtx knlist_lock;
MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
MTX_DEF);
static void knlist_mtx_lock(void *arg);
static void knlist_mtx_unlock(void *arg);
static void
knlist_mtx_lock(void *arg)
{
mtx_lock((struct mtx *)arg);
}
static void
knlist_mtx_unlock(void *arg)
{
mtx_unlock((struct mtx *)arg);
}
static void
knlist_mtx_assert_locked(void *arg)
{
mtx_assert((struct mtx *)arg, MA_OWNED);
}
static void
knlist_mtx_assert_unlocked(void *arg)
{
mtx_assert((struct mtx *)arg, MA_NOTOWNED);
}
static void
knlist_rw_rlock(void *arg)
{
rw_rlock((struct rwlock *)arg);
}
static void
knlist_rw_runlock(void *arg)
{
rw_runlock((struct rwlock *)arg);
}
static void
knlist_rw_assert_locked(void *arg)
{
rw_assert((struct rwlock *)arg, RA_LOCKED);
}
static void
knlist_rw_assert_unlocked(void *arg)
{
rw_assert((struct rwlock *)arg, RA_UNLOCKED);
}
void
knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
void (*kl_unlock)(void *),
void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *))
{
if (lock == NULL)
knl->kl_lockarg = &knlist_lock;
else
knl->kl_lockarg = lock;
if (kl_lock == NULL)
knl->kl_lock = knlist_mtx_lock;
else
knl->kl_lock = kl_lock;
if (kl_unlock == NULL)
knl->kl_unlock = knlist_mtx_unlock;
else
knl->kl_unlock = kl_unlock;
if (kl_assert_locked == NULL)
knl->kl_assert_locked = knlist_mtx_assert_locked;
else
knl->kl_assert_locked = kl_assert_locked;
if (kl_assert_unlocked == NULL)
knl->kl_assert_unlocked = knlist_mtx_assert_unlocked;
else
knl->kl_assert_unlocked = kl_assert_unlocked;
knl->kl_autodestroy = 0;
SLIST_INIT(&knl->kl_list);
}
void
knlist_init_mtx(struct knlist *knl, struct mtx *lock)
{
knlist_init(knl, lock, NULL, NULL, NULL, NULL);
}
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
struct knlist *
knlist_alloc(struct mtx *lock)
{
struct knlist *knl;
knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK);
knlist_init_mtx(knl, lock);
return (knl);
}
void
knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock)
{
knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock,
knlist_rw_assert_locked, knlist_rw_assert_unlocked);
}
void
knlist_destroy(struct knlist *knl)
{
KASSERT(KNLIST_EMPTY(knl),
("destroying knlist %p with knotes on it", knl));
}
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
void
knlist_detach(struct knlist *knl)
{
KNL_ASSERT_LOCKED(knl);
knl->kl_autodestroy = 1;
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
if (knlist_empty(knl)) {
knlist_destroy(knl);
free(knl, M_KQUEUE);
}
}
/*
* Even if we are locked, we may need to drop the lock to allow any influx
* knotes time to "settle".
*/
void
knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
{
struct knote *kn, *kn2;
struct kqueue *kq;
When filt_proc() removes event from the knlist due to the process exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen: - knote kn_knlist pointer is reset - INFLUX knote is removed from the process knlist. And, there are two consequences: - KN_LIST_UNLOCK() on such knote is nop - there is nothing which would block exit1() from processing past the knlist_destroy() (and knlist_destroy() resets knlist lock pointers). Both consequences result either in leaked process lock, or dereferencing NULL function pointers for locking. Handle this by stopping embedding the process knlist into struct proc. Instead, the knlist is allocated together with struct proc, but marked as autodestroy on the zombie reap, by knlist_detach() function. The knlist is freed when last kevent is removed from the list, in particular, at the zombie reap time if the list is empty. As result, the knlist_remove_inevent() is no longer needed and removed. Other changes: In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events from kn_sfflags for knote registered by kernel to only get NOTE_CHILD notifications. The flags leak resulted in excessive NOTE_EXEC/NOTE_FORK reports. Fix immediate note activation in filt_procattach(). Condition should be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT report for the exiting process. In knote_fork(), do not perform racy check for KN_INFLUX before kq lock is taken. Besides being racy, it did not accounted for notes just added by scan (KN_SCAN). Some minor and incomplete style fixes. Analyzed and tested by: Eric Badger <eric@badgerio.us> Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Approved by: re (gjb) Differential revision: https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl));
if (islocked)
KNL_ASSERT_LOCKED(knl);
else {
KNL_ASSERT_UNLOCKED(knl);
again: /* need to reacquire lock since we have dropped it */
knl->kl_lock(knl->kl_lockarg);
}
SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
kq = kn->kn_kq;
KQ_LOCK(kq);
if (kn_in_flux(kn)) {
KQ_UNLOCK(kq);
continue;
}
knlist_remove_kq(knl, kn, 1, 1);
if (killkn) {
kn_enter_flux(kn);
KQ_UNLOCK(kq);
knote_drop_detached(kn, td);
} else {
/* Make sure cleared knotes disappear soon */
kn->kn_flags |= EV_EOF | EV_ONESHOT;
KQ_UNLOCK(kq);
}
kq = NULL;
}
if (!SLIST_EMPTY(&knl->kl_list)) {
/* there are still in flux knotes remaining */
kn = SLIST_FIRST(&knl->kl_list);
kq = kn->kn_kq;
KQ_LOCK(kq);
KASSERT(kn_in_flux(kn), ("knote removed w/o list lock"));
knl->kl_unlock(knl->kl_lockarg);
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
kq = NULL;
goto again;
}
if (islocked)
KNL_ASSERT_LOCKED(knl);
else {
knl->kl_unlock(knl->kl_lockarg);
KNL_ASSERT_UNLOCKED(knl);
}
}
/*
Replace custom file descriptor array sleep lock constructed using a mutex and flags with an sxlock. This leads to a significant and measurable performance improvement as a result of access to shared locking for frequent lookup operations, reduced general overhead, and reduced overhead in the event of contention. All of these are imported for threaded applications where simultaneous access to a shared file descriptor array occurs frequently. Kris has reported 2x-4x transaction rate improvements on 8-core MySQL benchmarks; smaller improvements can be expected for many workloads as a result of reduced overhead. - Generally eliminate the distinction between "fast" and regular acquisisition of the filedesc lock; the plan is that they will now all be fast. Change all locking instances to either shared or exclusive locks. - Correct a bug (pointed out by kib) in fdfree() where previously msleep() was called without the mutex held; sx_sleep() is now always called with the sxlock held exclusively. - Universally hold the struct file lock over changes to struct file, rather than the filedesc lock or no lock. Always update the f_ops field last. A further memory barrier is required here in the future (discussed with jhb). - Improve locking and reference management in linux_at(), which fails to properly acquire vnode references before using vnode pointers. Annotate improper use of vn_fullpath(), which will be replaced at a future date. In fcntl(), we conservatively acquire an exclusive lock, even though in some cases a shared lock may be sufficient, which should be revisited. The dropping of the filedesc lock in fdgrowtable() is no longer required as the sxlock can be held over the sleep operation; we should consider removing that (pointed out by attilio). Tested by: kris Discussed with: jhb, kris, attilio, jeff
2007-04-04 09:11:34 +00:00
* Remove all knotes referencing a specified fd must be called with FILEDESC
* lock. This prevents a race where a new fd comes along and occupies the
* entry and we attach a knote to the fd.
*/
void
knote_fdclose(struct thread *td, int fd)
{
struct filedesc *fdp = td->td_proc->p_fd;
struct kqueue *kq;
struct knote *kn;
int influx;
Replace custom file descriptor array sleep lock constructed using a mutex and flags with an sxlock. This leads to a significant and measurable performance improvement as a result of access to shared locking for frequent lookup operations, reduced general overhead, and reduced overhead in the event of contention. All of these are imported for threaded applications where simultaneous access to a shared file descriptor array occurs frequently. Kris has reported 2x-4x transaction rate improvements on 8-core MySQL benchmarks; smaller improvements can be expected for many workloads as a result of reduced overhead. - Generally eliminate the distinction between "fast" and regular acquisisition of the filedesc lock; the plan is that they will now all be fast. Change all locking instances to either shared or exclusive locks. - Correct a bug (pointed out by kib) in fdfree() where previously msleep() was called without the mutex held; sx_sleep() is now always called with the sxlock held exclusively. - Universally hold the struct file lock over changes to struct file, rather than the filedesc lock or no lock. Always update the f_ops field last. A further memory barrier is required here in the future (discussed with jhb). - Improve locking and reference management in linux_at(), which fails to properly acquire vnode references before using vnode pointers. Annotate improper use of vn_fullpath(), which will be replaced at a future date. In fcntl(), we conservatively acquire an exclusive lock, even though in some cases a shared lock may be sufficient, which should be revisited. The dropping of the filedesc lock in fdgrowtable() is no longer required as the sxlock can be held over the sleep operation; we should consider removing that (pointed out by attilio). Tested by: kris Discussed with: jhb, kris, attilio, jeff
2007-04-04 09:11:34 +00:00
FILEDESC_XLOCK_ASSERT(fdp);
/*
* We shouldn't have to worry about new kevents appearing on fd
* since filedesc is locked.
*/
TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
KQ_LOCK(kq);
again:
influx = 0;
while (kq->kq_knlistsize > fd &&
(kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
if (kn_in_flux(kn)) {
/* someone else might be waiting on our knote */
if (influx)
wakeup(kq);
kq->kq_state |= KQ_FLUXWAIT;
msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
goto again;
}
kn_enter_flux(kn);
KQ_UNLOCK(kq);
influx = 1;
knote_drop(kn, td);
KQ_LOCK(kq);
}
KQ_UNLOCK_FLUX(kq);
}
}
static int
knote_attach(struct knote *kn, struct kqueue *kq)
{
struct klist *list;
KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn));
KQ_OWNED(kq);
if ((kq->kq_state & KQ_CLOSING) != 0)
return (EBADF);
if (kn->kn_fop->f_isfd) {
if (kn->kn_id >= kq->kq_knlistsize)
return (ENOMEM);
list = &kq->kq_knlist[kn->kn_id];
} else {
if (kq->kq_knhash == NULL)
return (ENOMEM);
list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
}
SLIST_INSERT_HEAD(list, kn, kn_link);
return (0);
}
static void
knote_drop(struct knote *kn, struct thread *td)
{
if ((kn->kn_status & KN_DETACHED) == 0)
kn->kn_fop->f_detach(kn);
knote_drop_detached(kn, td);
}
static void
knote_drop_detached(struct knote *kn, struct thread *td)
{
struct kqueue *kq;
struct klist *list;
kq = kn->kn_kq;
KASSERT((kn->kn_status & KN_DETACHED) != 0,
("knote %p still attached", kn));
KQ_NOTOWNED(kq);
KQ_LOCK(kq);
KASSERT(kn->kn_influx == 1,
("knote_drop called on %p with influx %d", kn, kn->kn_influx));
if (kn->kn_fop->f_isfd)
list = &kq->kq_knlist[kn->kn_id];
else
list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
if (!SLIST_EMPTY(list))
SLIST_REMOVE(list, kn, knote, kn_link);
if (kn->kn_status & KN_QUEUED)
knote_dequeue(kn);
KQ_UNLOCK_FLUX(kq);
if (kn->kn_fop->f_isfd) {
fdrop(kn->kn_fp, td);
kn->kn_fp = NULL;
}
kqueue_fo_release(kn->kn_kevent.filter);
kn->kn_fop = NULL;
knote_free(kn);
}
static void
knote_enqueue(struct knote *kn)
{
struct kqueue *kq = kn->kn_kq;
KQ_OWNED(kn->kn_kq);
KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
2004-08-12 18:06:21 +00:00
TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
kn->kn_status |= KN_QUEUED;
kq->kq_count++;
kqueue_wakeup(kq);
}
static void
knote_dequeue(struct knote *kn)
{
struct kqueue *kq = kn->kn_kq;
KQ_OWNED(kn->kn_kq);
KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
2004-08-12 18:06:21 +00:00
TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
kn->kn_status &= ~KN_QUEUED;
kq->kq_count--;
}
static void
knote_init(void)
{
knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, 0);
}
SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
static struct knote *
knote_alloc(int mflag)
{
return (uma_zalloc(knote_zone, mflag | M_ZERO));
}
static void
knote_free(struct knote *kn)
{
uma_zfree(knote_zone, kn);
}
/*
* Register the kev w/ the kq specified by fd.
*/
int
kqfd_register(int fd, struct kevent *kev, struct thread *td, int mflag)
{
struct kqueue *kq;
struct file *fp;
Change the cap_rights_t type from uint64_t to a structure that we can extend in the future in a backward compatible (API and ABI) way. The cap_rights_t represents capability rights. We used to use one bit to represent one right, but we are running out of spare bits. Currently the new structure provides place for 114 rights (so 50 more than the previous cap_rights_t), but it is possible to grow the structure to hold at least 285 rights, although we can make it even larger if 285 rights won't be enough. The structure definition looks like this: struct cap_rights { uint64_t cr_rights[CAP_RIGHTS_VERSION + 2]; }; The initial CAP_RIGHTS_VERSION is 0. The top two bits in the first element of the cr_rights[] array contain total number of elements in the array - 2. This means if those two bits are equal to 0, we have 2 array elements. The top two bits in all remaining array elements should be 0. The next five bits in all array elements contain array index. Only one bit is used and bit position in this five-bits range defines array index. This means there can be at most five array elements in the future. To define new right the CAPRIGHT() macro must be used. The macro takes two arguments - an array index and a bit to set, eg. #define CAP_PDKILL CAPRIGHT(1, 0x0000000000000800ULL) We still support aliases that combine few rights, but the rights have to belong to the same array element, eg: #define CAP_LOOKUP CAPRIGHT(0, 0x0000000000000400ULL) #define CAP_FCHMOD CAPRIGHT(0, 0x0000000000002000ULL) #define CAP_FCHMODAT (CAP_FCHMOD | CAP_LOOKUP) There is new API to manage the new cap_rights_t structure: cap_rights_t *cap_rights_init(cap_rights_t *rights, ...); void cap_rights_set(cap_rights_t *rights, ...); void cap_rights_clear(cap_rights_t *rights, ...); bool cap_rights_is_set(const cap_rights_t *rights, ...); bool cap_rights_is_valid(const cap_rights_t *rights); void cap_rights_merge(cap_rights_t *dst, const cap_rights_t *src); void cap_rights_remove(cap_rights_t *dst, const cap_rights_t *src); bool cap_rights_contains(const cap_rights_t *big, const cap_rights_t *little); Capability rights to the cap_rights_init(), cap_rights_set(), cap_rights_clear() and cap_rights_is_set() functions are provided by separating them with commas, eg: cap_rights_t rights; cap_rights_init(&rights, CAP_READ, CAP_WRITE, CAP_FSTAT); There is no need to terminate the list of rights, as those functions are actually macros that take care of the termination, eg: #define cap_rights_set(rights, ...) \ __cap_rights_set((rights), __VA_ARGS__, 0ULL) void __cap_rights_set(cap_rights_t *rights, ...); Thanks to using one bit as an array index we can assert in those functions that there are no two rights belonging to different array elements provided together. For example this is illegal and will be detected, because CAP_LOOKUP belongs to element 0 and CAP_PDKILL to element 1: cap_rights_init(&rights, CAP_LOOKUP | CAP_PDKILL); Providing several rights that belongs to the same array's element this way is correct, but is not advised. It should only be used for aliases definition. This commit also breaks compatibility with some existing Capsicum system calls, but I see no other way to do that. This should be fine as Capsicum is still experimental and this change is not going to 9.x. Sponsored by: The FreeBSD Foundation
2013-09-05 00:09:56 +00:00
cap_rights_t rights;
int error;
error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp);
Change the cap_rights_t type from uint64_t to a structure that we can extend in the future in a backward compatible (API and ABI) way. The cap_rights_t represents capability rights. We used to use one bit to represent one right, but we are running out of spare bits. Currently the new structure provides place for 114 rights (so 50 more than the previous cap_rights_t), but it is possible to grow the structure to hold at least 285 rights, although we can make it even larger if 285 rights won't be enough. The structure definition looks like this: struct cap_rights { uint64_t cr_rights[CAP_RIGHTS_VERSION + 2]; }; The initial CAP_RIGHTS_VERSION is 0. The top two bits in the first element of the cr_rights[] array contain total number of elements in the array - 2. This means if those two bits are equal to 0, we have 2 array elements. The top two bits in all remaining array elements should be 0. The next five bits in all array elements contain array index. Only one bit is used and bit position in this five-bits range defines array index. This means there can be at most five array elements in the future. To define new right the CAPRIGHT() macro must be used. The macro takes two arguments - an array index and a bit to set, eg. #define CAP_PDKILL CAPRIGHT(1, 0x0000000000000800ULL) We still support aliases that combine few rights, but the rights have to belong to the same array element, eg: #define CAP_LOOKUP CAPRIGHT(0, 0x0000000000000400ULL) #define CAP_FCHMOD CAPRIGHT(0, 0x0000000000002000ULL) #define CAP_FCHMODAT (CAP_FCHMOD | CAP_LOOKUP) There is new API to manage the new cap_rights_t structure: cap_rights_t *cap_rights_init(cap_rights_t *rights, ...); void cap_rights_set(cap_rights_t *rights, ...); void cap_rights_clear(cap_rights_t *rights, ...); bool cap_rights_is_set(const cap_rights_t *rights, ...); bool cap_rights_is_valid(const cap_rights_t *rights); void cap_rights_merge(cap_rights_t *dst, const cap_rights_t *src); void cap_rights_remove(cap_rights_t *dst, const cap_rights_t *src); bool cap_rights_contains(const cap_rights_t *big, const cap_rights_t *little); Capability rights to the cap_rights_init(), cap_rights_set(), cap_rights_clear() and cap_rights_is_set() functions are provided by separating them with commas, eg: cap_rights_t rights; cap_rights_init(&rights, CAP_READ, CAP_WRITE, CAP_FSTAT); There is no need to terminate the list of rights, as those functions are actually macros that take care of the termination, eg: #define cap_rights_set(rights, ...) \ __cap_rights_set((rights), __VA_ARGS__, 0ULL) void __cap_rights_set(cap_rights_t *rights, ...); Thanks to using one bit as an array index we can assert in those functions that there are no two rights belonging to different array elements provided together. For example this is illegal and will be detected, because CAP_LOOKUP belongs to element 0 and CAP_PDKILL to element 1: cap_rights_init(&rights, CAP_LOOKUP | CAP_PDKILL); Providing several rights that belongs to the same array's element this way is correct, but is not advised. It should only be used for aliases definition. This commit also breaks compatibility with some existing Capsicum system calls, but I see no other way to do that. This should be fine as Capsicum is still experimental and this change is not going to 9.x. Sponsored by: The FreeBSD Foundation
2013-09-05 00:09:56 +00:00
if (error != 0)
return (error);
if ((error = kqueue_acquire(fp, &kq)) != 0)
goto noacquire;
error = kqueue_register(kq, kev, td, mflag);
kqueue_release(kq, 0);
noacquire:
fdrop(fp, td);
return (error);
}