d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
50179c5ec7
freebsd-dev/sys/kern/kern_sig.c
Jonathan T. Looney dbec10e088 Fetch the sigfastblock value in syscalls that wait for signals 
We have seen several cases of processes which have become "stuck" in
kern_sigsuspend(). When this occurs, the kernel's td_sigblock_val
is set to 0x10 (one block outstanding) and the userspace copy of the
word is set to 0 (unblocked). Because the kernel's cached value
shows that signals are blocked, kern_sigsuspend() blocks almost all
signals, which means the process hangs indefinitely in sigsuspend().

It is not entirely clear what is causing this condition to occur.
However, it seems to make sense to add some protection against this
case by fetching the latest sigfastblock value from userspace for
syscalls which will sleep waiting for signals. Here, the change is
applied to kern_sigsuspend() and kern_sigtimedwait().

Reviewed by:	kib
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D29225
2021-03-12 18:14:17 +00:00

4260 lines
102 KiB
C
Raw Blame History

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/ctype.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>
#include <sys/acct.h>
#include <sys/capsicum.h>
#include <sys/compressor.h>
#include <sys/condvar.h>
#include <sys/devctl.h>
#include <sys/event.h>
#include <sys/fcntl.h>
#include <sys/imgact.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/ktrace.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/refcount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/procdesc.h>
#include <sys/ptrace.h>
#include <sys/posix4.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
#include <sys/sdt.h>
#include <sys/sbuf.h>
#include <sys/sleepqueue.h>
#include <sys/smp.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/syslog.h>
#include <sys/sysproto.h>
#include <sys/timers.h>
#include <sys/unistd.h>
#include <sys/wait.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/uma.h>
#include <sys/jail.h>
#include <machine/cpu.h>
#include <security/audit/audit.h>
#define ONSIG 32 /* NSIG for osig* syscalls. XXX. */
SDT_PROVIDER_DECLARE(proc);
SDT_PROBE_DEFINE3(proc, , , signal__send,
"struct thread *", "struct proc *", "int");
SDT_PROBE_DEFINE2(proc, , , signal__clear,
"int", "ksiginfo_t *");
SDT_PROBE_DEFINE3(proc, , , signal__discard,
"struct thread *", "struct proc *", "int");
static int coredump(struct thread *);
static int killpg1(struct thread *td, int sig, int pgid, int all,
ksiginfo_t *ksi);
static int issignal(struct thread *td);
static void reschedule_signals(struct proc *p, sigset_t block, int flags);
static int sigprop(int sig);
static void tdsigwakeup(struct thread *, int, sig_t, int);
static int sig_suspend_threads(struct thread *, struct proc *, int);
static int filt_sigattach(struct knote *kn);
static void filt_sigdetach(struct knote *kn);
static int filt_signal(struct knote *kn, long hint);
static struct thread *sigtd(struct proc *p, int sig, bool fast_sigblock);
static void sigqueue_start(void);
static uma_zone_t ksiginfo_zone = NULL;
struct filterops sig_filtops = {
.f_isfd = 0,
.f_attach = filt_sigattach,
.f_detach = filt_sigdetach,
.f_event = filt_signal,
};
static int kern_logsigexit = 1;
SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
&kern_logsigexit, 0,
"Log processes quitting on abnormal signals to syslog(3)");
static int kern_forcesigexit = 1;
SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW,
&kern_forcesigexit, 0, "Force trap signal to be handled");
static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"POSIX real time signal");
static int max_pending_per_proc = 128;
SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW,
&max_pending_per_proc, 0, "Max pending signals per proc");
static int preallocate_siginfo = 1024;
SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RDTUN,
&preallocate_siginfo, 0, "Preallocated signal memory size");
static int signal_overflow = 0;
SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD,
&signal_overflow, 0, "Number of signals overflew");
static int signal_alloc_fail = 0;
SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD,
&signal_alloc_fail, 0, "signals failed to be allocated");
static int kern_lognosys = 0;
SYSCTL_INT(_kern, OID_AUTO, lognosys, CTLFLAG_RWTUN, &kern_lognosys, 0,
"Log invalid syscalls");
__read_frequently bool sigfastblock_fetch_always = false;
SYSCTL_BOOL(_kern, OID_AUTO, sigfastblock_fetch_always, CTLFLAG_RWTUN,
&sigfastblock_fetch_always, 0,
"Fetch sigfastblock word on each syscall entry for proper "
"blocking semantic");
SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL);
/*
* Policy -- Can ucred cr1 send SIGIO to process cr2?
* Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
* in the right situations.
*/
#define CANSIGIO(cr1, cr2) \
((cr1)->cr_uid == 0 || \
(cr1)->cr_ruid == (cr2)->cr_ruid || \
(cr1)->cr_uid == (cr2)->cr_ruid || \
(cr1)->cr_ruid == (cr2)->cr_uid || \
(cr1)->cr_uid == (cr2)->cr_uid)
static int sugid_coredump;
SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RWTUN,
&sugid_coredump, 0, "Allow setuid and setgid processes to dump core");
static int capmode_coredump;
SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RWTUN,
&capmode_coredump, 0, "Allow processes in capability mode to dump core");
static int do_coredump = 1;
SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
&do_coredump, 0, "Enable/Disable coredumps");
static int set_core_nodump_flag = 0;
SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag,
0, "Enable setting the NODUMP flag on coredump files");
static int coredump_devctl = 0;
SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl,
0, "Generate a devctl notification when processes coredump");
/*
* Signal properties and actions.
* The array below categorizes the signals and their default actions
* according to the following properties:
*/
#define SIGPROP_KILL 0x01 /* terminates process by default */
#define SIGPROP_CORE 0x02 /* ditto and coredumps */
#define SIGPROP_STOP 0x04 /* suspend process */
#define SIGPROP_TTYSTOP 0x08 /* ditto, from tty */
#define SIGPROP_IGNORE 0x10 /* ignore by default */
#define SIGPROP_CONT 0x20 /* continue if suspended */
#define SIGPROP_CANTMASK 0x40 /* non-maskable, catchable */
static int sigproptbl[NSIG] = {
[SIGHUP] = SIGPROP_KILL,
[SIGINT] = SIGPROP_KILL,
[SIGQUIT] = SIGPROP_KILL | SIGPROP_CORE,
[SIGILL] = SIGPROP_KILL | SIGPROP_CORE,
[SIGTRAP] = SIGPROP_KILL | SIGPROP_CORE,
[SIGABRT] = SIGPROP_KILL | SIGPROP_CORE,
[SIGEMT] = SIGPROP_KILL | SIGPROP_CORE,
[SIGFPE] = SIGPROP_KILL | SIGPROP_CORE,
[SIGKILL] = SIGPROP_KILL,
[SIGBUS] = SIGPROP_KILL | SIGPROP_CORE,
[SIGSEGV] = SIGPROP_KILL | SIGPROP_CORE,
[SIGSYS] = SIGPROP_KILL | SIGPROP_CORE,
[SIGPIPE] = SIGPROP_KILL,
[SIGALRM] = SIGPROP_KILL,
[SIGTERM] = SIGPROP_KILL,
[SIGURG] = SIGPROP_IGNORE,
[SIGSTOP] = SIGPROP_STOP,
[SIGTSTP] = SIGPROP_STOP | SIGPROP_TTYSTOP,
[SIGCONT] = SIGPROP_IGNORE | SIGPROP_CONT,
[SIGCHLD] = SIGPROP_IGNORE,
[SIGTTIN] = SIGPROP_STOP | SIGPROP_TTYSTOP,
[SIGTTOU] = SIGPROP_STOP | SIGPROP_TTYSTOP,
[SIGIO] = SIGPROP_IGNORE,
[SIGXCPU] = SIGPROP_KILL,
[SIGXFSZ] = SIGPROP_KILL,
[SIGVTALRM] = SIGPROP_KILL,
[SIGPROF] = SIGPROP_KILL,
[SIGWINCH] = SIGPROP_IGNORE,
[SIGINFO] = SIGPROP_IGNORE,
[SIGUSR1] = SIGPROP_KILL,
[SIGUSR2] = SIGPROP_KILL,
};
sigset_t fastblock_mask;
static void
sigqueue_start(void)
{
ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
uma_prealloc(ksiginfo_zone, preallocate_siginfo);
p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS);
p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1);
p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc);
SIGFILLSET(fastblock_mask);
SIG_CANTMASK(fastblock_mask);
}
ksiginfo_t *
ksiginfo_alloc(int wait)
{
int flags;
flags = M_ZERO;
if (! wait)
flags |= M_NOWAIT;
if (ksiginfo_zone != NULL)
return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags));
return (NULL);
}
void
ksiginfo_free(ksiginfo_t *ksi)
{
uma_zfree(ksiginfo_zone, ksi);
}
static __inline int
ksiginfo_tryfree(ksiginfo_t *ksi)
{
if (!(ksi->ksi_flags & KSI_EXT)) {
uma_zfree(ksiginfo_zone, ksi);
return (1);
}
return (0);
}
void
sigqueue_init(sigqueue_t *list, struct proc *p)
{
SIGEMPTYSET(list->sq_signals);
SIGEMPTYSET(list->sq_kill);
SIGEMPTYSET(list->sq_ptrace);
TAILQ_INIT(&list->sq_list);
list->sq_proc = p;
list->sq_flags = SQ_INIT;
}
/*
* Get a signal's ksiginfo.
* Return:
* 0 - signal not found
* others - signal number
*/
static int
sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si)
{
struct proc *p = sq->sq_proc;
struct ksiginfo *ksi, *next;
int count = 0;
KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
if (!SIGISMEMBER(sq->sq_signals, signo))
return (0);
if (SIGISMEMBER(sq->sq_ptrace, signo)) {
count++;
SIGDELSET(sq->sq_ptrace, signo);
si->ksi_flags |= KSI_PTRACE;
}
if (SIGISMEMBER(sq->sq_kill, signo)) {
count++;
if (count == 1)
SIGDELSET(sq->sq_kill, signo);
}
TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
if (ksi->ksi_signo == signo) {
if (count == 0) {
TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
ksi->ksi_sigq = NULL;
ksiginfo_copy(ksi, si);
if (ksiginfo_tryfree(ksi) && p != NULL)
p->p_pendingcnt--;
}
if (++count > 1)
break;
}
}
if (count <= 1)
SIGDELSET(sq->sq_signals, signo);
si->ksi_signo = signo;
return (signo);
}
void
sigqueue_take(ksiginfo_t *ksi)
{
struct ksiginfo *kp;
struct proc *p;
sigqueue_t *sq;
if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL)
return;
p = sq->sq_proc;
TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
ksi->ksi_sigq = NULL;
if (!(ksi->ksi_flags & KSI_EXT) && p != NULL)
p->p_pendingcnt--;
for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL;
kp = TAILQ_NEXT(kp, ksi_link)) {
if (kp->ksi_signo == ksi->ksi_signo)
break;
}
if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) &&
!SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo))
SIGDELSET(sq->sq_signals, ksi->ksi_signo);
}
static int
sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si)
{
struct proc *p = sq->sq_proc;
struct ksiginfo *ksi;
int ret = 0;
KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
/*
* SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path
* for these signals.
*/
if (signo == SIGKILL || signo == SIGSTOP || si == NULL) {
SIGADDSET(sq->sq_kill, signo);
goto out_set_bit;
}
/* directly insert the ksi, don't copy it */
if (si->ksi_flags & KSI_INS) {
if (si->ksi_flags & KSI_HEAD)
TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link);
else
TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link);
si->ksi_sigq = sq;
goto out_set_bit;
}
if (__predict_false(ksiginfo_zone == NULL)) {
SIGADDSET(sq->sq_kill, signo);
goto out_set_bit;
}
if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) {
signal_overflow++;
ret = EAGAIN;
} else if ((ksi = ksiginfo_alloc(0)) == NULL) {
signal_alloc_fail++;
ret = EAGAIN;
} else {
if (p != NULL)
p->p_pendingcnt++;
ksiginfo_copy(si, ksi);
ksi->ksi_signo = signo;
if (si->ksi_flags & KSI_HEAD)
TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link);
else
TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link);
ksi->ksi_sigq = sq;
}
if (ret != 0) {
if ((si->ksi_flags & KSI_PTRACE) != 0) {
SIGADDSET(sq->sq_ptrace, signo);
ret = 0;
goto out_set_bit;
} else if ((si->ksi_flags & KSI_TRAP) != 0 ||
(si->ksi_flags & KSI_SIGQ) == 0) {
SIGADDSET(sq->sq_kill, signo);
ret = 0;
goto out_set_bit;
}
return (ret);
}
out_set_bit:
SIGADDSET(sq->sq_signals, signo);
return (ret);
}
void
sigqueue_flush(sigqueue_t *sq)
{
struct proc *p = sq->sq_proc;
ksiginfo_t *ksi;
KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
if (p != NULL)
PROC_LOCK_ASSERT(p, MA_OWNED);
while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) {
TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
ksi->ksi_sigq = NULL;
if (ksiginfo_tryfree(ksi) && p != NULL)
p->p_pendingcnt--;
}
SIGEMPTYSET(sq->sq_signals);
SIGEMPTYSET(sq->sq_kill);
SIGEMPTYSET(sq->sq_ptrace);
}
static void
sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set)
{
sigset_t tmp;
struct proc *p1, *p2;
ksiginfo_t *ksi, *next;
KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited"));
KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited"));
p1 = src->sq_proc;
p2 = dst->sq_proc;
/* Move siginfo to target list */
TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) {
if (SIGISMEMBER(*set, ksi->ksi_signo)) {
TAILQ_REMOVE(&src->sq_list, ksi, ksi_link);
if (p1 != NULL)
p1->p_pendingcnt--;
TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link);
ksi->ksi_sigq = dst;
if (p2 != NULL)
p2->p_pendingcnt++;
}
}
/* Move pending bits to target list */
tmp = src->sq_kill;
SIGSETAND(tmp, *set);
SIGSETOR(dst->sq_kill, tmp);
SIGSETNAND(src->sq_kill, tmp);
tmp = src->sq_ptrace;
SIGSETAND(tmp, *set);
SIGSETOR(dst->sq_ptrace, tmp);
SIGSETNAND(src->sq_ptrace, tmp);
tmp = src->sq_signals;
SIGSETAND(tmp, *set);
SIGSETOR(dst->sq_signals, tmp);
SIGSETNAND(src->sq_signals, tmp);
}
#if 0
static void
sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo)
{
sigset_t set;
SIGEMPTYSET(set);
SIGADDSET(set, signo);
sigqueue_move_set(src, dst, &set);
}
#endif
static void
sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set)
{
struct proc *p = sq->sq_proc;
ksiginfo_t *ksi, *next;
KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited"));
/* Remove siginfo queue */
TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
if (SIGISMEMBER(*set, ksi->ksi_signo)) {
TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
ksi->ksi_sigq = NULL;
if (ksiginfo_tryfree(ksi) && p != NULL)
p->p_pendingcnt--;
}
}
SIGSETNAND(sq->sq_kill, *set);
SIGSETNAND(sq->sq_ptrace, *set);
SIGSETNAND(sq->sq_signals, *set);
}
void
sigqueue_delete(sigqueue_t *sq, int signo)
{
sigset_t set;
SIGEMPTYSET(set);
SIGADDSET(set, signo);
sigqueue_delete_set(sq, &set);
}
/* Remove a set of signals for a process */
static void
sigqueue_delete_set_proc(struct proc *p, const sigset_t *set)
{
sigqueue_t worklist;
struct thread *td0;
PROC_LOCK_ASSERT(p, MA_OWNED);
sigqueue_init(&worklist, NULL);
sigqueue_move_set(&p->p_sigqueue, &worklist, set);
FOREACH_THREAD_IN_PROC(p, td0)
sigqueue_move_set(&td0->td_sigqueue, &worklist, set);
sigqueue_flush(&worklist);
}
void
sigqueue_delete_proc(struct proc *p, int signo)
{
sigset_t set;
SIGEMPTYSET(set);
SIGADDSET(set, signo);
sigqueue_delete_set_proc(p, &set);
}
static void
sigqueue_delete_stopmask_proc(struct proc *p)
{
sigset_t set;
SIGEMPTYSET(set);
SIGADDSET(set, SIGSTOP);
SIGADDSET(set, SIGTSTP);
SIGADDSET(set, SIGTTIN);
SIGADDSET(set, SIGTTOU);
sigqueue_delete_set_proc(p, &set);
}
/*
* Determine signal that should be delivered to thread td, the current
* thread, 0 if none. If there is a pending stop signal with default
* action, the process stops in issignal().
*/
int
cursig(struct thread *td)
{
PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
return (SIGPENDING(td) ? issignal(td) : 0);
}
/*
* Arrange for ast() to handle unmasked pending signals on return to user
* mode. This must be called whenever a signal is added to td_sigqueue or
* unmasked in td_sigmask.
*/
void
signotify(struct thread *td)
{
PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
if (SIGPENDING(td)) {
thread_lock(td);
td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
thread_unlock(td);
}
}
/*
* Returns 1 (true) if altstack is configured for the thread, and the
* passed stack bottom address falls into the altstack range. Handles
* the 43 compat special case where the alt stack size is zero.
*/
int
sigonstack(size_t sp)
{
struct thread *td;
td = curthread;
if ((td->td_pflags & TDP_ALTSTACK) == 0)
return (0);
#if defined(COMPAT_43)
if (SV_PROC_FLAG(td->td_proc, SV_AOUT) && td->td_sigstk.ss_size == 0)
return ((td->td_sigstk.ss_flags & SS_ONSTACK) != 0);
#endif
return (sp >= (size_t)td->td_sigstk.ss_sp &&
sp < td->td_sigstk.ss_size + (size_t)td->td_sigstk.ss_sp);
}
static __inline int
sigprop(int sig)
{
if (sig > 0 && sig < nitems(sigproptbl))
return (sigproptbl[sig]);
return (0);
}
int
sig_ffs(sigset_t *set)
{
int i;
for (i = 0; i < _SIG_WORDS; i++)
if (set->__bits[i])
return (ffs(set->__bits[i]) + (i * 32));
return (0);
}
static bool
sigact_flag_test(const struct sigaction *act, int flag)
{
/*
* SA_SIGINFO is reset when signal disposition is set to
* ignore or default. Other flags are kept according to user
* settings.
*/
return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO ||
((__sighandler_t *)act->sa_sigaction != SIG_IGN &&
(__sighandler_t *)act->sa_sigaction != SIG_DFL)));
}
/*
* kern_sigaction
* sigaction
* freebsd4_sigaction
* osigaction
*/
int
kern_sigaction(struct thread *td, int sig, const struct sigaction *act,
struct sigaction *oact, int flags)
{
struct sigacts *ps;
struct proc *p = td->td_proc;
if (!_SIG_VALID(sig))
return (EINVAL);
if (act != NULL && act->sa_handler != SIG_DFL &&
act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK |
SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER |
SA_NOCLDWAIT | SA_SIGINFO)) != 0)
return (EINVAL);
PROC_LOCK(p);
ps = p->p_sigacts;
mtx_lock(&ps->ps_mtx);
if (oact) {
memset(oact, 0, sizeof(*oact));
oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
if (SIGISMEMBER(ps->ps_sigonstack, sig))
oact->sa_flags |= SA_ONSTACK;
if (!SIGISMEMBER(ps->ps_sigintr, sig))
oact->sa_flags |= SA_RESTART;
if (SIGISMEMBER(ps->ps_sigreset, sig))
oact->sa_flags |= SA_RESETHAND;
if (SIGISMEMBER(ps->ps_signodefer, sig))
oact->sa_flags |= SA_NODEFER;
if (SIGISMEMBER(ps->ps_siginfo, sig)) {
oact->sa_flags |= SA_SIGINFO;
oact->sa_sigaction =
(__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)];
} else
oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP)
oact->sa_flags |= SA_NOCLDSTOP;
if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT)
oact->sa_flags |= SA_NOCLDWAIT;
}
if (act) {
if ((sig == SIGKILL || sig == SIGSTOP) &&
act->sa_handler != SIG_DFL) {
mtx_unlock(&ps->ps_mtx);
PROC_UNLOCK(p);
return (EINVAL);
}
/*
* Change setting atomically.
*/
ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
if (sigact_flag_test(act, SA_SIGINFO)) {
ps->ps_sigact[_SIG_IDX(sig)] =
(__sighandler_t *)act->sa_sigaction;
SIGADDSET(ps->ps_siginfo, sig);
} else {
ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
SIGDELSET(ps->ps_siginfo, sig);
}
if (!sigact_flag_test(act, SA_RESTART))
SIGADDSET(ps->ps_sigintr, sig);
else
SIGDELSET(ps->ps_sigintr, sig);
if (sigact_flag_test(act, SA_ONSTACK))
SIGADDSET(ps->ps_sigonstack, sig);
else
SIGDELSET(ps->ps_sigonstack, sig);
if (sigact_flag_test(act, SA_RESETHAND))
SIGADDSET(ps->ps_sigreset, sig);
else
SIGDELSET(ps->ps_sigreset, sig);
if (sigact_flag_test(act, SA_NODEFER))
SIGADDSET(ps->ps_signodefer, sig);
else
SIGDELSET(ps->ps_signodefer, sig);
if (sig == SIGCHLD) {
if (act->sa_flags & SA_NOCLDSTOP)
ps->ps_flag |= PS_NOCLDSTOP;
else
ps->ps_flag &= ~PS_NOCLDSTOP;
if (act->sa_flags & SA_NOCLDWAIT) {
/*
* Paranoia: since SA_NOCLDWAIT is implemented
* by reparenting the dying child to PID 1 (and
* trust it to reap the zombie), PID 1 itself
* is forbidden to set SA_NOCLDWAIT.
*/
if (p->p_pid == 1)
ps->ps_flag &= ~PS_NOCLDWAIT;
else
ps->ps_flag |= PS_NOCLDWAIT;
} else
ps->ps_flag &= ~PS_NOCLDWAIT;
if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
ps->ps_flag |= PS_CLDSIGIGN;
else
ps->ps_flag &= ~PS_CLDSIGIGN;
}
/*
* Set bit in ps_sigignore for signals that are set to SIG_IGN,
* and for signals set to SIG_DFL where the default is to
* ignore. However, don't put SIGCONT in ps_sigignore, as we
* have to restart the process.
*/
if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
(sigprop(sig) & SIGPROP_IGNORE &&
ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
/* never to be seen again */
sigqueue_delete_proc(p, sig);
if (sig != SIGCONT)
/* easier in psignal */
SIGADDSET(ps->ps_sigignore, sig);
SIGDELSET(ps->ps_sigcatch, sig);
} else {
SIGDELSET(ps->ps_sigignore, sig);
if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
SIGDELSET(ps->ps_sigcatch, sig);
else
SIGADDSET(ps->ps_sigcatch, sig);
}
#ifdef COMPAT_FREEBSD4
if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
(flags & KSA_FREEBSD4) == 0)
SIGDELSET(ps->ps_freebsd4, sig);
else
SIGADDSET(ps->ps_freebsd4, sig);
#endif
#ifdef COMPAT_43
if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
(flags & KSA_OSIGSET) == 0)
SIGDELSET(ps->ps_osigset, sig);
else
SIGADDSET(ps->ps_osigset, sig);
#endif
}
mtx_unlock(&ps->ps_mtx);
PROC_UNLOCK(p);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct sigaction_args {
int sig;
struct sigaction *act;
struct sigaction *oact;
};
#endif
int
sys_sigaction(struct thread *td, struct sigaction_args *uap)
{
struct sigaction act, oact;
struct sigaction *actp, *oactp;
int error;
actp = (uap->act != NULL) ? &act : NULL;
oactp = (uap->oact != NULL) ? &oact : NULL;
if (actp) {
error = copyin(uap->act, actp, sizeof(act));
if (error)
return (error);
}
error = kern_sigaction(td, uap->sig, actp, oactp, 0);
if (oactp && !error)
error = copyout(oactp, uap->oact, sizeof(oact));
return (error);
}
#ifdef COMPAT_FREEBSD4
#ifndef _SYS_SYSPROTO_H_
struct freebsd4_sigaction_args {
int sig;
struct sigaction *act;
struct sigaction *oact;
};
#endif
int
freebsd4_sigaction(struct thread *td, struct freebsd4_sigaction_args *uap)
{
struct sigaction act, oact;
struct sigaction *actp, *oactp;
int error;
actp = (uap->act != NULL) ? &act : NULL;
oactp = (uap->oact != NULL) ? &oact : NULL;
if (actp) {
error = copyin(uap->act, actp, sizeof(act));
if (error)
return (error);
}
error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
if (oactp && !error)
error = copyout(oactp, uap->oact, sizeof(oact));
return (error);
}
#endif /* COMAPT_FREEBSD4 */
#ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
#ifndef _SYS_SYSPROTO_H_
struct osigaction_args {
int signum;
struct osigaction *nsa;
struct osigaction *osa;
};
#endif
int
osigaction(struct thread *td, struct osigaction_args *uap)
{
struct osigaction sa;
struct sigaction nsa, osa;
struct sigaction *nsap, *osap;
int error;
if (uap->signum <= 0 || uap->signum >= ONSIG)
return (EINVAL);
nsap = (uap->nsa != NULL) ? &nsa : NULL;
osap = (uap->osa != NULL) ? &osa : NULL;
if (nsap) {
error = copyin(uap->nsa, &sa, sizeof(sa));
if (error)
return (error);
nsap->sa_handler = sa.sa_handler;
nsap->sa_flags = sa.sa_flags;
OSIG2SIG(sa.sa_mask, nsap->sa_mask);
}
error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
if (osap && !error) {
sa.sa_handler = osap->sa_handler;
sa.sa_flags = osap->sa_flags;
SIG2OSIG(osap->sa_mask, sa.sa_mask);
error = copyout(&sa, uap->osa, sizeof(sa));
}
return (error);
}
#if !defined(__i386__)
/* Avoid replicating the same stub everywhere */
int
osigreturn(struct thread *td, struct osigreturn_args *uap)
{
return (nosys(td, (struct nosys_args *)uap));
}
#endif
#endif /* COMPAT_43 */
/*
* Initialize signal state for process 0;
* set to ignore signals that are ignored by default.
*/
void
siginit(struct proc *p)
{
int i;
struct sigacts *ps;
PROC_LOCK(p);
ps = p->p_sigacts;
mtx_lock(&ps->ps_mtx);
for (i = 1; i <= NSIG; i++) {
if (sigprop(i) & SIGPROP_IGNORE && i != SIGCONT) {
SIGADDSET(ps->ps_sigignore, i);
}
}
mtx_unlock(&ps->ps_mtx);
PROC_UNLOCK(p);
}
/*
* Reset specified signal to the default disposition.
*/
static void
sigdflt(struct sigacts *ps, int sig)
{
mtx_assert(&ps->ps_mtx, MA_OWNED);
SIGDELSET(ps->ps_sigcatch, sig);
if ((sigprop(sig) & SIGPROP_IGNORE) != 0 && sig != SIGCONT)
SIGADDSET(ps->ps_sigignore, sig);
ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
SIGDELSET(ps->ps_siginfo, sig);
}
/*
* Reset signals for an exec of the specified process.
*/
void
execsigs(struct proc *p)
{
sigset_t osigignore;
struct sigacts *ps;
int sig;
struct thread *td;
/*
* Reset caught signals. Held signals remain held
* through td_sigmask (unless they were caught,
* and are now ignored by default).
*/
PROC_LOCK_ASSERT(p, MA_OWNED);
ps = p->p_sigacts;
mtx_lock(&ps->ps_mtx);
sig_drop_caught(p);
/*
* As CloudABI processes cannot modify signal handlers, fully
* reset all signals to their default behavior. Do ignore
* SIGPIPE, as it would otherwise be impossible to recover from
* writes to broken pipes and sockets.
*/
if (SV_PROC_ABI(p) == SV_ABI_CLOUDABI) {
osigignore = ps->ps_sigignore;
while (SIGNOTEMPTY(osigignore)) {
sig = sig_ffs(&osigignore);
SIGDELSET(osigignore, sig);
if (sig != SIGPIPE)
sigdflt(ps, sig);
}
SIGADDSET(ps->ps_sigignore, SIGPIPE);
}
/*
* Reset stack state to the user stack.
* Clear set of signals caught on the signal stack.
*/
td = curthread;
MPASS(td->td_proc == p);
td->td_sigstk.ss_flags = SS_DISABLE;
td->td_sigstk.ss_size = 0;
td->td_sigstk.ss_sp = 0;
td->td_pflags &= ~TDP_ALTSTACK;
/*
* Reset no zombies if child dies flag as Solaris does.
*/
ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
mtx_unlock(&ps->ps_mtx);
}
/*
* kern_sigprocmask()
*
* Manipulate signal mask.
*/
int
kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset,
int flags)
{
sigset_t new_block, oset1;
struct proc *p;
int error;
p = td->td_proc;
if ((flags & SIGPROCMASK_PROC_LOCKED) != 0)
PROC_LOCK_ASSERT(p, MA_OWNED);
else
PROC_LOCK(p);
mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0
? MA_OWNED : MA_NOTOWNED);
if (oset != NULL)
*oset = td->td_sigmask;
error = 0;
if (set != NULL) {
switch (how) {
case SIG_BLOCK:
SIG_CANTMASK(*set);
oset1 = td->td_sigmask;
SIGSETOR(td->td_sigmask, *set);
new_block = td->td_sigmask;
SIGSETNAND(new_block, oset1);
break;
case SIG_UNBLOCK:
SIGSETNAND(td->td_sigmask, *set);
signotify(td);
goto out;
case SIG_SETMASK:
SIG_CANTMASK(*set);
oset1 = td->td_sigmask;
if (flags & SIGPROCMASK_OLD)
SIGSETLO(td->td_sigmask, *set);
else
td->td_sigmask = *set;
new_block = td->td_sigmask;
SIGSETNAND(new_block, oset1);
signotify(td);
break;
default:
error = EINVAL;
goto out;
}
/*
* The new_block set contains signals that were not previously
* blocked, but are blocked now.
*
* In case we block any signal that was not previously blocked
* for td, and process has the signal pending, try to schedule
* signal delivery to some thread that does not block the
* signal, possibly waking it up.
*/
if (p->p_numthreads != 1)
reschedule_signals(p, new_block, flags);
}
out:
if (!(flags & SIGPROCMASK_PROC_LOCKED))
PROC_UNLOCK(p);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct sigprocmask_args {
int how;
const sigset_t *set;
sigset_t *oset;
};
#endif
int
sys_sigprocmask(struct thread *td, struct sigprocmask_args *uap)
{
sigset_t set, oset;
sigset_t *setp, *osetp;
int error;
setp = (uap->set != NULL) ? &set : NULL;
osetp = (uap->oset != NULL) ? &oset : NULL;
if (setp) {
error = copyin(uap->set, setp, sizeof(set));
if (error)
return (error);
}
error = kern_sigprocmask(td, uap->how, setp, osetp, 0);
if (osetp && !error) {
error = copyout(osetp, uap->oset, sizeof(oset));
}
return (error);
}
#ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
#ifndef _SYS_SYSPROTO_H_
struct osigprocmask_args {
int how;
osigset_t mask;
};
#endif
int
osigprocmask(struct thread *td, struct osigprocmask_args *uap)
{
sigset_t set, oset;
int error;
OSIG2SIG(uap->mask, set);
error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
SIG2OSIG(oset, td->td_retval[0]);
return (error);
}
#endif /* COMPAT_43 */
int
sys_sigwait(struct thread *td, struct sigwait_args *uap)
{
ksiginfo_t ksi;
sigset_t set;
int error;
error = copyin(uap->set, &set, sizeof(set));
if (error) {
td->td_retval[0] = error;
return (0);
}
error = kern_sigtimedwait(td, set, &ksi, NULL);
if (error) {
if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT)
error = ERESTART;
if (error == ERESTART)
return (error);
td->td_retval[0] = error;
return (0);
}
error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo));
td->td_retval[0] = error;
return (0);
}
int
sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
{
struct timespec ts;
struct timespec *timeout;
sigset_t set;
ksiginfo_t ksi;
int error;
if (uap->timeout) {
error = copyin(uap->timeout, &ts, sizeof(ts));
if (error)
return (error);
timeout = &ts;
} else
timeout = NULL;
error = copyin(uap->set, &set, sizeof(set));
if (error)
return (error);
error = kern_sigtimedwait(td, set, &ksi, timeout);
if (error)
return (error);
if (uap->info)
error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
if (error == 0)
td->td_retval[0] = ksi.ksi_signo;
return (error);
}
int
sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
{
ksiginfo_t ksi;
sigset_t set;
int error;
error = copyin(uap->set, &set, sizeof(set));
if (error)
return (error);
error = kern_sigtimedwait(td, set, &ksi, NULL);
if (error)
return (error);
if (uap->info)
error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
if (error == 0)
td->td_retval[0] = ksi.ksi_signo;
return (error);
}
static void
proc_td_siginfo_capture(struct thread *td, siginfo_t *si)
{
struct thread *thr;
FOREACH_THREAD_IN_PROC(td->td_proc, thr) {
if (thr == td)
thr->td_si = *si;
else
thr->td_si.si_signo = 0;
}
}
int
kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi,
struct timespec *timeout)
{
struct sigacts *ps;
sigset_t saved_mask, new_block;
struct proc *p;
int error, sig, timo, timevalid = 0;
struct timespec rts, ets, ts;
struct timeval tv;
bool traced;
p = td->td_proc;
error = 0;
ets.tv_sec = 0;
ets.tv_nsec = 0;
traced = false;
/* Ensure the sigfastblock value is up to date. */
sigfastblock_fetch(td);
if (timeout != NULL) {
if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
timevalid = 1;
getnanouptime(&rts);
timespecadd(&rts, timeout, &ets);
}
}
ksiginfo_init(ksi);
/* Some signals can not be waited for. */
SIG_CANTMASK(waitset);
ps = p->p_sigacts;
PROC_LOCK(p);
saved_mask = td->td_sigmask;
SIGSETNAND(td->td_sigmask, waitset);
for (;;) {
mtx_lock(&ps->ps_mtx);
sig = cursig(td);
mtx_unlock(&ps->ps_mtx);
KASSERT(sig >= 0, ("sig %d", sig));
if (sig != 0 && SIGISMEMBER(waitset, sig)) {
if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 ||
sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) {
error = 0;
break;
}
}
if (error != 0)
break;
/*
* POSIX says this must be checked after looking for pending
* signals.
*/
if (timeout != NULL) {
if (!timevalid) {
error = EINVAL;
break;
}
getnanouptime(&rts);
if (timespeccmp(&rts, &ets, >=)) {
error = EAGAIN;
break;
}
timespecsub(&ets, &rts, &ts);
TIMESPEC_TO_TIMEVAL(&tv, &ts);
timo = tvtohz(&tv);
} else {
timo = 0;
}
if (traced) {
error = EINTR;
break;
}
error = msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", timo);
if (timeout != NULL) {
if (error == ERESTART) {
/* Timeout can not be restarted. */
error = EINTR;
} else if (error == EAGAIN) {
/* We will calculate timeout by ourself. */
error = 0;
}
}
/*
* If PTRACE_SCE or PTRACE_SCX were set after
* userspace entered the syscall, return spurious
* EINTR after wait was done. Only do this as last
* resort after rechecking for possible queued signals
* and expired timeouts.
*/
if (error == 0 && (p->p_ptevents & PTRACE_SYSCALL) != 0)
traced = true;
}
new_block = saved_mask;
SIGSETNAND(new_block, td->td_sigmask);
td->td_sigmask = saved_mask;
/*
* Fewer signals can be delivered to us, reschedule signal
* notification.
*/
if (p->p_numthreads != 1)
reschedule_signals(p, new_block, 0);
if (error == 0) {
SDT_PROBE2(proc, , , signal__clear, sig, ksi);
if (ksi->ksi_code == SI_TIMER)
itimer_accept(p, ksi->ksi_timerid, ksi);
#ifdef KTRACE
if (KTRPOINT(td, KTR_PSIG)) {
sig_t action;
mtx_lock(&ps->ps_mtx);
action = ps->ps_sigact[_SIG_IDX(sig)];
mtx_unlock(&ps->ps_mtx);
ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code);
}
#endif
if (sig == SIGKILL) {
proc_td_siginfo_capture(td, &ksi->ksi_info);
sigexit(td, sig);
}
}
PROC_UNLOCK(p);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct sigpending_args {
sigset_t *set;
};
#endif
int
sys_sigpending(struct thread *td, struct sigpending_args *uap)
{
struct proc *p = td->td_proc;
sigset_t pending;
PROC_LOCK(p);
pending = p->p_sigqueue.sq_signals;
SIGSETOR(pending, td->td_sigqueue.sq_signals);
PROC_UNLOCK(p);
return (copyout(&pending, uap->set, sizeof(sigset_t)));
}
#ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
#ifndef _SYS_SYSPROTO_H_
struct osigpending_args {
int dummy;
};
#endif
int
osigpending(struct thread *td, struct osigpending_args *uap)
{
struct proc *p = td->td_proc;
sigset_t pending;
PROC_LOCK(p);
pending = p->p_sigqueue.sq_signals;
SIGSETOR(pending, td->td_sigqueue.sq_signals);
PROC_UNLOCK(p);
SIG2OSIG(pending, td->td_retval[0]);
return (0);
}
#endif /* COMPAT_43 */
#if defined(COMPAT_43)
/*
* Generalized interface signal handler, 4.3-compatible.
*/
#ifndef _SYS_SYSPROTO_H_
struct osigvec_args {
int signum;
struct sigvec *nsv;
struct sigvec *osv;
};
#endif
/* ARGSUSED */
int
osigvec(struct thread *td, struct osigvec_args *uap)
{
struct sigvec vec;
struct sigaction nsa, osa;
struct sigaction *nsap, *osap;
int error;
if (uap->signum <= 0 || uap->signum >= ONSIG)
return (EINVAL);
nsap = (uap->nsv != NULL) ? &nsa : NULL;
osap = (uap->osv != NULL) ? &osa : NULL;
if (nsap) {
error = copyin(uap->nsv, &vec, sizeof(vec));
if (error)
return (error);
nsap->sa_handler = vec.sv_handler;
OSIG2SIG(vec.sv_mask, nsap->sa_mask);
nsap->sa_flags = vec.sv_flags;
nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */
}
error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
if (osap && !error) {
vec.sv_handler = osap->sa_handler;
SIG2OSIG(osap->sa_mask, vec.sv_mask);
vec.sv_flags = osap->sa_flags;
vec.sv_flags &= ~SA_NOCLDWAIT;
vec.sv_flags ^= SA_RESTART;
error = copyout(&vec, uap->osv, sizeof(vec));
}
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct osigblock_args {
int mask;
};
#endif
int
osigblock(struct thread *td, struct osigblock_args *uap)
{
sigset_t set, oset;
OSIG2SIG(uap->mask, set);
kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
SIG2OSIG(oset, td->td_retval[0]);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct osigsetmask_args {
int mask;
};
#endif
int
osigsetmask(struct thread *td, struct osigsetmask_args *uap)
{
sigset_t set, oset;
OSIG2SIG(uap->mask, set);
kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
SIG2OSIG(oset, td->td_retval[0]);
return (0);
}
#endif /* COMPAT_43 */
/*
* Suspend calling thread until signal, providing mask to be set in the
* meantime.
*/
#ifndef _SYS_SYSPROTO_H_
struct sigsuspend_args {
const sigset_t *sigmask;
};
#endif
/* ARGSUSED */
int
sys_sigsuspend(struct thread *td, struct sigsuspend_args *uap)
{
sigset_t mask;
int error;
error = copyin(uap->sigmask, &mask, sizeof(mask));
if (error)
return (error);
return (kern_sigsuspend(td, mask));
}
int
kern_sigsuspend(struct thread *td, sigset_t mask)
{
struct proc *p = td->td_proc;
int has_sig, sig;
/* Ensure the sigfastblock value is up to date. */
sigfastblock_fetch(td);
/*
* When returning from sigsuspend, we want
* the old mask to be restored after the
* signal handler has finished. Thus, we
* save it here and mark the sigacts structure
* to indicate this.
*/
PROC_LOCK(p);
kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask,
SIGPROCMASK_PROC_LOCKED);
td->td_pflags |= TDP_OLDMASK;
/*
* Process signals now. Otherwise, we can get spurious wakeup
* due to signal entered process queue, but delivered to other
* thread. But sigsuspend should return only on signal
* delivery.
*/
(p->p_sysent->sv_set_syscall_retval)(td, EINTR);
for (has_sig = 0; !has_sig;) {
while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause",
0) == 0)
/* void */;
thread_suspend_check(0);
mtx_lock(&p->p_sigacts->ps_mtx);
while ((sig = cursig(td)) != 0) {
KASSERT(sig >= 0, ("sig %d", sig));
has_sig += postsig(sig);
}
mtx_unlock(&p->p_sigacts->ps_mtx);
/*
* If PTRACE_SCE or PTRACE_SCX were set after
* userspace entered the syscall, return spurious
* EINTR.
*/
if ((p->p_ptevents & PTRACE_SYSCALL) != 0)
has_sig += 1;
}
PROC_UNLOCK(p);
td->td_errno = EINTR;
td->td_pflags |= TDP_NERRNO;
return (EJUSTRETURN);
}
#ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */
/*
* Compatibility sigsuspend call for old binaries. Note nonstandard calling
* convention: libc stub passes mask, not pointer, to save a copyin.
*/
#ifndef _SYS_SYSPROTO_H_
struct osigsuspend_args {
osigset_t mask;
};
#endif
/* ARGSUSED */
int
osigsuspend(struct thread *td, struct osigsuspend_args *uap)
{
sigset_t mask;
OSIG2SIG(uap->mask, mask);
return (kern_sigsuspend(td, mask));
}
#endif /* COMPAT_43 */
#if defined(COMPAT_43)
#ifndef _SYS_SYSPROTO_H_
struct osigstack_args {
struct sigstack *nss;
struct sigstack *oss;
};
#endif
/* ARGSUSED */
int
osigstack(struct thread *td, struct osigstack_args *uap)
{
struct sigstack nss, oss;
int error = 0;
if (uap->nss != NULL) {
error = copyin(uap->nss, &nss, sizeof(nss));
if (error)
return (error);
}
oss.ss_sp = td->td_sigstk.ss_sp;
oss.ss_onstack = sigonstack(cpu_getstack(td));
if (uap->nss != NULL) {
td->td_sigstk.ss_sp = nss.ss_sp;
td->td_sigstk.ss_size = 0;
td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK;
td->td_pflags |= TDP_ALTSTACK;
}
if (uap->oss != NULL)
error = copyout(&oss, uap->oss, sizeof(oss));
return (error);
}
#endif /* COMPAT_43 */
#ifndef _SYS_SYSPROTO_H_
struct sigaltstack_args {
stack_t *ss;
stack_t *oss;
};
#endif
/* ARGSUSED */
int
sys_sigaltstack(struct thread *td, struct sigaltstack_args *uap)
{
stack_t ss, oss;
int error;
if (uap->ss != NULL) {
error = copyin(uap->ss, &ss, sizeof(ss));
if (error)
return (error);
}
error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
(uap->oss != NULL) ? &oss : NULL);
if (error)
return (error);
if (uap->oss != NULL)
error = copyout(&oss, uap->oss, sizeof(stack_t));
return (error);
}
int
kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
{
struct proc *p = td->td_proc;
int oonstack;
oonstack = sigonstack(cpu_getstack(td));
if (oss != NULL) {
*oss = td->td_sigstk;
oss->ss_flags = (td->td_pflags & TDP_ALTSTACK)
? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
}
if (ss != NULL) {
if (oonstack)
return (EPERM);
if ((ss->ss_flags & ~SS_DISABLE) != 0)
return (EINVAL);
if (!(ss->ss_flags & SS_DISABLE)) {
if (ss->ss_size < p->p_sysent->sv_minsigstksz)
return (ENOMEM);
td->td_sigstk = *ss;
td->td_pflags |= TDP_ALTSTACK;
} else {
td->td_pflags &= ~TDP_ALTSTACK;
}
}
return (0);
}
struct killpg1_ctx {
struct thread *td;
ksiginfo_t *ksi;
int sig;
bool sent;
bool found;
int ret;
};
static void
killpg1_sendsig(struct proc *p, bool notself, struct killpg1_ctx *arg)
{
int err;
if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) != 0 ||
(notself && p == arg->td->td_proc) || p->p_state == PRS_NEW)
return;
PROC_LOCK(p);
err = p_cansignal(arg->td, p, arg->sig);
if (err == 0 && arg->sig != 0)
pksignal(p, arg->sig, arg->ksi);
PROC_UNLOCK(p);
if (err != ESRCH)
arg->found = true;
if (err == 0)
arg->sent = true;
else if (arg->ret == 0 && err != ESRCH && err != EPERM)
arg->ret = err;
}
/*
* Common code for kill process group/broadcast kill.
* cp is calling process.
*/
static int
killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi)
{
struct proc *p;
struct pgrp *pgrp;
struct killpg1_ctx arg;
arg.td = td;
arg.ksi = ksi;
arg.sig = sig;
arg.sent = false;
arg.found = false;
arg.ret = 0;
if (all) {
/*
* broadcast
*/
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
killpg1_sendsig(p, true, &arg);
}
sx_sunlock(&allproc_lock);
} else {
sx_slock(&proctree_lock);
if (pgid == 0) {
/*
* zero pgid means send to my process group.
*/
pgrp = td->td_proc->p_pgrp;
PGRP_LOCK(pgrp);
} else {
pgrp = pgfind(pgid);
if (pgrp == NULL) {
sx_sunlock(&proctree_lock);
return (ESRCH);
}
}
sx_sunlock(&proctree_lock);
LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
killpg1_sendsig(p, false, &arg);
}
PGRP_UNLOCK(pgrp);
}
MPASS(arg.ret != 0 || arg.found || !arg.sent);
if (arg.ret == 0 && !arg.sent)
arg.ret = arg.found ? EPERM : ESRCH;
return (arg.ret);
}
#ifndef _SYS_SYSPROTO_H_
struct kill_args {
int pid;
int signum;
};
#endif
/* ARGSUSED */
int
sys_kill(struct thread *td, struct kill_args *uap)
{
return (kern_kill(td, uap->pid, uap->signum));
}
int
kern_kill(struct thread *td, pid_t pid, int signum)
{
ksiginfo_t ksi;
struct proc *p;
int error;
/*
* A process in capability mode can send signals only to himself.
* The main rationale behind this is that abort(3) is implemented as
* kill(getpid(), SIGABRT).
*/
if (IN_CAPABILITY_MODE(td) && pid != td->td_proc->p_pid)
return (ECAPMODE);
AUDIT_ARG_SIGNUM(signum);
AUDIT_ARG_PID(pid);
if ((u_int)signum > _SIG_MAXSIG)
return (EINVAL);
ksiginfo_init(&ksi);
ksi.ksi_signo = signum;
ksi.ksi_code = SI_USER;
ksi.ksi_pid = td->td_proc->p_pid;
ksi.ksi_uid = td->td_ucred->cr_ruid;
if (pid > 0) {
/* kill single process */
if ((p = pfind_any(pid)) == NULL)
return (ESRCH);
AUDIT_ARG_PROCESS(p);
error = p_cansignal(td, p, signum);
if (error == 0 && signum)
pksignal(p, signum, &ksi);
PROC_UNLOCK(p);
return (error);
}
switch (pid) {
case -1: /* broadcast signal */
return (killpg1(td, signum, 0, 1, &ksi));
case 0: /* signal own process group */
return (killpg1(td, signum, 0, 0, &ksi));
default: /* negative explicit process group */
return (killpg1(td, signum, -pid, 0, &ksi));
}
/* NOTREACHED */
}
int
sys_pdkill(struct thread *td, struct pdkill_args *uap)
{
struct proc *p;
int error;
AUDIT_ARG_SIGNUM(uap->signum);
AUDIT_ARG_FD(uap->fd);
if ((u_int)uap->signum > _SIG_MAXSIG)
return (EINVAL);
error = procdesc_find(td, uap->fd, &cap_pdkill_rights, &p);
if (error)
return (error);
AUDIT_ARG_PROCESS(p);
error = p_cansignal(td, p, uap->signum);
if (error == 0 && uap->signum)
kern_psignal(p, uap->signum);
PROC_UNLOCK(p);
return (error);
}
#if defined(COMPAT_43)
#ifndef _SYS_SYSPROTO_H_
struct okillpg_args {
int pgid;
int signum;
};
#endif
/* ARGSUSED */
int
okillpg(struct thread *td, struct okillpg_args *uap)
{
ksiginfo_t ksi;
AUDIT_ARG_SIGNUM(uap->signum);
AUDIT_ARG_PID(uap->pgid);
if ((u_int)uap->signum > _SIG_MAXSIG)
return (EINVAL);
ksiginfo_init(&ksi);
ksi.ksi_signo = uap->signum;
ksi.ksi_code = SI_USER;
ksi.ksi_pid = td->td_proc->p_pid;
ksi.ksi_uid = td->td_ucred->cr_ruid;
return (killpg1(td, uap->signum, uap->pgid, 0, &ksi));
}
#endif /* COMPAT_43 */
#ifndef _SYS_SYSPROTO_H_
struct sigqueue_args {
pid_t pid;
int signum;
/* union sigval */ void *value;
};
#endif
int
sys_sigqueue(struct thread *td, struct sigqueue_args *uap)
{
union sigval sv;
sv.sival_ptr = uap->value;
return (kern_sigqueue(td, uap->pid, uap->signum, &sv));
}
int
kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value)
{
ksiginfo_t ksi;
struct proc *p;
int error;
if ((u_int)signum > _SIG_MAXSIG)
return (EINVAL);
/*
* Specification says sigqueue can only send signal to
* single process.
*/
if (pid <= 0)
return (EINVAL);
if ((p = pfind_any(pid)) == NULL)
return (ESRCH);
error = p_cansignal(td, p, signum);
if (error == 0 && signum != 0) {
ksiginfo_init(&ksi);
ksi.ksi_flags = KSI_SIGQ;
ksi.ksi_signo = signum;
ksi.ksi_code = SI_QUEUE;
ksi.ksi_pid = td->td_proc->p_pid;
ksi.ksi_uid = td->td_ucred->cr_ruid;
ksi.ksi_value = *value;
error = pksignal(p, ksi.ksi_signo, &ksi);
}
PROC_UNLOCK(p);
return (error);
}
/*
* Send a signal to a process group.
*/
void
gsignal(int pgid, int sig, ksiginfo_t *ksi)
{
struct pgrp *pgrp;
if (pgid != 0) {
sx_slock(&proctree_lock);
pgrp = pgfind(pgid);
sx_sunlock(&proctree_lock);
if (pgrp != NULL) {
pgsignal(pgrp, sig, 0, ksi);
PGRP_UNLOCK(pgrp);
}
}
}
/*
* Send a signal to a process group. If checktty is 1,
* limit to members which have a controlling terminal.
*/
void
pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi)
{
struct proc *p;
if (pgrp) {
PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
PROC_LOCK(p);
if (p->p_state == PRS_NORMAL &&
(checkctty == 0 || p->p_flag & P_CONTROLT))
pksignal(p, sig, ksi);
PROC_UNLOCK(p);
}
}
}
/*
* Recalculate the signal mask and reset the signal disposition after
* usermode frame for delivery is formed. Should be called after
* mach-specific routine, because sysent->sv_sendsig() needs correct
* ps_siginfo and signal mask.
*/
static void
postsig_done(int sig, struct thread *td, struct sigacts *ps)
{
sigset_t mask;
mtx_assert(&ps->ps_mtx, MA_OWNED);
td->td_ru.ru_nsignals++;
mask = ps->ps_catchmask[_SIG_IDX(sig)];
if (!SIGISMEMBER(ps->ps_signodefer, sig))
SIGADDSET(mask, sig);
kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
if (SIGISMEMBER(ps->ps_sigreset, sig))
sigdflt(ps, sig);
}
/*
* Send a signal caused by a trap to the current thread. If it will be
* caught immediately, deliver it with correct code. Otherwise, post it
* normally.
*/
void
trapsignal(struct thread *td, ksiginfo_t *ksi)
{
struct sigacts *ps;
struct proc *p;
sigset_t sigmask;
int code, sig;
p = td->td_proc;
sig = ksi->ksi_signo;
code = ksi->ksi_code;
KASSERT(_SIG_VALID(sig), ("invalid signal"));
sigfastblock_fetch(td);
PROC_LOCK(p);
ps = p->p_sigacts;
mtx_lock(&ps->ps_mtx);
sigmask = td->td_sigmask;
if (td->td_sigblock_val != 0)
SIGSETOR(sigmask, fastblock_mask);
if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
!SIGISMEMBER(sigmask, sig)) {
#ifdef KTRACE
if (KTRPOINT(curthread, KTR_PSIG))
ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
&td->td_sigmask, code);
#endif
(*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)],
ksi, &td->td_sigmask);
postsig_done(sig, td, ps);
mtx_unlock(&ps->ps_mtx);
} else {
/*
* Avoid a possible infinite loop if the thread
* masking the signal or process is ignoring the
* signal.
*/
if (kern_forcesigexit && (SIGISMEMBER(sigmask, sig) ||
ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) {
SIGDELSET(td->td_sigmask, sig);
SIGDELSET(ps->ps_sigcatch, sig);
SIGDELSET(ps->ps_sigignore, sig);
ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
td->td_pflags &= ~TDP_SIGFASTBLOCK;
td->td_sigblock_val = 0;
}
mtx_unlock(&ps->ps_mtx);
p->p_sig = sig; /* XXX to verify code */
tdsendsignal(p, td, sig, ksi);
}
PROC_UNLOCK(p);
}
static struct thread *
sigtd(struct proc *p, int sig, bool fast_sigblock)
{
struct thread *td, *signal_td;
PROC_LOCK_ASSERT(p, MA_OWNED);
MPASS(!fast_sigblock || p == curproc);
/*
* Check if current thread can handle the signal without
* switching context to another thread.
*/
if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig) &&
(!fast_sigblock || curthread->td_sigblock_val == 0))
return (curthread);
signal_td = NULL;
FOREACH_THREAD_IN_PROC(p, td) {
if (!SIGISMEMBER(td->td_sigmask, sig) && (!fast_sigblock ||
td != curthread || td->td_sigblock_val == 0)) {
signal_td = td;
break;
}
}
if (signal_td == NULL)
signal_td = FIRST_THREAD_IN_PROC(p);
return (signal_td);
}
/*
* Send the signal to the process. If the signal has an action, the action
* is usually performed by the target process rather than the caller; we add
* the signal to the set of pending signals for the process.
*
* Exceptions:
* o When a stop signal is sent to a sleeping process that takes the
* default action, the process is stopped without awakening it.
* o SIGCONT restarts stopped processes (or puts them back to sleep)
* regardless of the signal action (eg, blocked or ignored).
*
* Other ignored signals are discarded immediately.
*
* NB: This function may be entered from the debugger via the "kill" DDB
* command. There is little that can be done to mitigate the possibly messy
* side effects of this unwise possibility.
*/
void
kern_psignal(struct proc *p, int sig)
{
ksiginfo_t ksi;
ksiginfo_init(&ksi);
ksi.ksi_signo = sig;
ksi.ksi_code = SI_KERNEL;
(void) tdsendsignal(p, NULL, sig, &ksi);
}
int
pksignal(struct proc *p, int sig, ksiginfo_t *ksi)
{
return (tdsendsignal(p, NULL, sig, ksi));
}
/* Utility function for finding a thread to send signal event to. */
int
sigev_findtd(struct proc *p ,struct sigevent *sigev, struct thread **ttd)
{
struct thread *td;
if (sigev->sigev_notify == SIGEV_THREAD_ID) {
td = tdfind(sigev->sigev_notify_thread_id, p->p_pid);
if (td == NULL)
return (ESRCH);
*ttd = td;
} else {
*ttd = NULL;
PROC_LOCK(p);
}
return (0);
}
void
tdsignal(struct thread *td, int sig)
{
ksiginfo_t ksi;
ksiginfo_init(&ksi);
ksi.ksi_signo = sig;
ksi.ksi_code = SI_KERNEL;
(void) tdsendsignal(td->td_proc, td, sig, &ksi);
}
void
tdksignal(struct thread *td, int sig, ksiginfo_t *ksi)
{
(void) tdsendsignal(td->td_proc, td, sig, ksi);
}
int
tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
{
sig_t action;
sigqueue_t *sigqueue;
int prop;
struct sigacts *ps;
int intrval;
int ret = 0;
int wakeup_swapper;
MPASS(td == NULL || p == td->td_proc);
PROC_LOCK_ASSERT(p, MA_OWNED);
if (!_SIG_VALID(sig))
panic("%s(): invalid signal %d", __func__, sig);
KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__));
/*
* IEEE Std 1003.1-2001: return success when killing a zombie.
*/
if (p->p_state == PRS_ZOMBIE) {
if (ksi && (ksi->ksi_flags & KSI_INS))
ksiginfo_tryfree(ksi);
return (ret);
}
ps = p->p_sigacts;
KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig);
prop = sigprop(sig);
if (td == NULL) {
td = sigtd(p, sig, false);
sigqueue = &p->p_sigqueue;
} else
sigqueue = &td->td_sigqueue;
SDT_PROBE3(proc, , , signal__send, td, p, sig);
/*
* If the signal is being ignored,
* then we forget about it immediately.
* (Note: we don't set SIGCONT in ps_sigignore,
* and if it is set to SIG_IGN,
* action will be SIG_DFL here.)
*/
mtx_lock(&ps->ps_mtx);
if (SIGISMEMBER(ps->ps_sigignore, sig)) {
SDT_PROBE3(proc, , , signal__discard, td, p, sig);
mtx_unlock(&ps->ps_mtx);
if (ksi && (ksi->ksi_flags & KSI_INS))
ksiginfo_tryfree(ksi);
return (ret);
}
if (SIGISMEMBER(td->td_sigmask, sig))
action = SIG_HOLD;
else if (SIGISMEMBER(ps->ps_sigcatch, sig))
action = SIG_CATCH;
else
action = SIG_DFL;
if (SIGISMEMBER(ps->ps_sigintr, sig))
intrval = EINTR;
else
intrval = ERESTART;
mtx_unlock(&ps->ps_mtx);
if (prop & SIGPROP_CONT)
sigqueue_delete_stopmask_proc(p);
else if (prop & SIGPROP_STOP) {
/*
* If sending a tty stop signal to a member of an orphaned
* process group, discard the signal here if the action
* is default; don't stop the process below if sleeping,
* and don't clear any pending SIGCONT.
*/
if ((prop & SIGPROP_TTYSTOP) != 0 &&
(p->p_pgrp->pg_flags & PGRP_ORPHANED) != 0 &&
action == SIG_DFL) {
if (ksi && (ksi->ksi_flags & KSI_INS))
ksiginfo_tryfree(ksi);
return (ret);
}
sigqueue_delete_proc(p, SIGCONT);
if (p->p_flag & P_CONTINUED) {
p->p_flag &= ~P_CONTINUED;
PROC_LOCK(p->p_pptr);
sigqueue_take(p->p_ksi);
PROC_UNLOCK(p->p_pptr);
}
}
ret = sigqueue_add(sigqueue, sig, ksi);
if (ret != 0)
return (ret);
signotify(td);
/*
* Defer further processing for signals which are held,
* except that stopped processes must be continued by SIGCONT.
*/
if (action == SIG_HOLD &&
!((prop & SIGPROP_CONT) && (p->p_flag & P_STOPPED_SIG)))
return (ret);
wakeup_swapper = 0;
/*
* Some signals have a process-wide effect and a per-thread
* component. Most processing occurs when the process next
* tries to cross the user boundary, however there are some
* times when processing needs to be done immediately, such as
* waking up threads so that they can cross the user boundary.
* We try to do the per-process part here.
*/
if (P_SHOULDSTOP(p)) {
KASSERT(!(p->p_flag & P_WEXIT),
("signal to stopped but exiting process"));
if (sig == SIGKILL) {
/*
* If traced process is already stopped,
* then no further action is necessary.
*/
if (p->p_flag & P_TRACED)
goto out;
/*
* SIGKILL sets process running.
* It will die elsewhere.
* All threads must be restarted.
*/
p->p_flag &= ~P_STOPPED_SIG;
goto runfast;
}
if (prop & SIGPROP_CONT) {
/*
* If traced process is already stopped,
* then no further action is necessary.
*/
if (p->p_flag & P_TRACED)
goto out;
/*
* If SIGCONT is default (or ignored), we continue the
* process but don't leave the signal in sigqueue as
* it has no further action. If SIGCONT is held, we
* continue the process and leave the signal in
* sigqueue. If the process catches SIGCONT, let it
* handle the signal itself. If it isn't waiting on
* an event, it goes back to run state.
* Otherwise, process goes back to sleep state.
*/
p->p_flag &= ~P_STOPPED_SIG;
PROC_SLOCK(p);
if (p->p_numthreads == p->p_suspcount) {
PROC_SUNLOCK(p);
p->p_flag |= P_CONTINUED;
p->p_xsig = SIGCONT;
PROC_LOCK(p->p_pptr);
childproc_continued(p);
PROC_UNLOCK(p->p_pptr);
PROC_SLOCK(p);
}
if (action == SIG_DFL) {
thread_unsuspend(p);
PROC_SUNLOCK(p);
sigqueue_delete(sigqueue, sig);
goto out;
}
if (action == SIG_CATCH) {
/*
* The process wants to catch it so it needs
* to run at least one thread, but which one?
*/
PROC_SUNLOCK(p);
goto runfast;
}
/*
* The signal is not ignored or caught.
*/
thread_unsuspend(p);
PROC_SUNLOCK(p);
goto out;
}
if (prop & SIGPROP_STOP) {
/*
* If traced process is already stopped,
* then no further action is necessary.
*/
if (p->p_flag & P_TRACED)
goto out;
/*
* Already stopped, don't need to stop again
* (If we did the shell could get confused).
* Just make sure the signal STOP bit set.
*/
p->p_flag |= P_STOPPED_SIG;
sigqueue_delete(sigqueue, sig);
goto out;
}
/*
* All other kinds of signals:
* If a thread is sleeping interruptibly, simulate a
* wakeup so that when it is continued it will be made
* runnable and can look at the signal. However, don't make
* the PROCESS runnable, leave it stopped.
* It may run a bit until it hits a thread_suspend_check().
*/
PROC_SLOCK(p);
thread_lock(td);
if (TD_CAN_ABORT(td))
wakeup_swapper = sleepq_abort(td, intrval);
else
thread_unlock(td);
PROC_SUNLOCK(p);
goto out;
/*
* Mutexes are short lived. Threads waiting on them will
* hit thread_suspend_check() soon.
*/
} else if (p->p_state == PRS_NORMAL) {
if (p->p_flag & P_TRACED || action == SIG_CATCH) {
tdsigwakeup(td, sig, action, intrval);
goto out;
}
MPASS(action == SIG_DFL);
if (prop & SIGPROP_STOP) {
if (p->p_flag & (P_PPWAIT|P_WEXIT))
goto out;
p->p_flag |= P_STOPPED_SIG;
p->p_xsig = sig;
PROC_SLOCK(p);
wakeup_swapper = sig_suspend_threads(td, p, 1);
if (p->p_numthreads == p->p_suspcount) {
/*
* only thread sending signal to another
* process can reach here, if thread is sending
* signal to its process, because thread does
* not suspend itself here, p_numthreads
* should never be equal to p_suspcount.
*/
thread_stopped(p);
PROC_SUNLOCK(p);
sigqueue_delete_proc(p, p->p_xsig);
} else
PROC_SUNLOCK(p);
goto out;
}
} else {
/* Not in "NORMAL" state. discard the signal. */
sigqueue_delete(sigqueue, sig);
goto out;
}
/*
* The process is not stopped so we need to apply the signal to all the
* running threads.
*/
runfast:
tdsigwakeup(td, sig, action, intrval);
PROC_SLOCK(p);
thread_unsuspend(p);
PROC_SUNLOCK(p);
out:
/* If we jump here, proc slock should not be owned. */
PROC_SLOCK_ASSERT(p, MA_NOTOWNED);
if (wakeup_swapper)
kick_proc0();
return (ret);
}
/*
* The force of a signal has been directed against a single
* thread. We need to see what we can do about knocking it
* out of any sleep it may be in etc.
*/
static void
tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
{
struct proc *p = td->td_proc;
int prop, wakeup_swapper;
PROC_LOCK_ASSERT(p, MA_OWNED);
prop = sigprop(sig);
PROC_SLOCK(p);
thread_lock(td);
/*
* Bring the priority of a thread up if we want it to get
* killed in this lifetime. Be careful to avoid bumping the
* priority of the idle thread, since we still allow to signal
* kernel processes.
*/
if (action == SIG_DFL && (prop & SIGPROP_KILL) != 0 &&
td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
sched_prio(td, PUSER);
if (TD_ON_SLEEPQ(td)) {
/*
* If thread is sleeping uninterruptibly
* we can't interrupt the sleep... the signal will
* be noticed when the process returns through
* trap() or syscall().
*/
if ((td->td_flags & TDF_SINTR) == 0)
goto out;
/*
* If SIGCONT is default (or ignored) and process is
* asleep, we are finished; the process should not
* be awakened.
*/
if ((prop & SIGPROP_CONT) && action == SIG_DFL) {
thread_unlock(td);
PROC_SUNLOCK(p);
sigqueue_delete(&p->p_sigqueue, sig);
/*
* It may be on either list in this state.
* Remove from both for now.
*/
sigqueue_delete(&td->td_sigqueue, sig);
return;
}
/*
* Don't awaken a sleeping thread for SIGSTOP if the
* STOP signal is deferred.
*/
if ((prop & SIGPROP_STOP) != 0 && (td->td_flags & (TDF_SBDRY |
TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
goto out;
/*
* Give low priority threads a better chance to run.
*/
if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
sched_prio(td, PUSER);
wakeup_swapper = sleepq_abort(td, intrval);
PROC_SUNLOCK(p);
if (wakeup_swapper)
kick_proc0();
return;
}
/*
* Other states do nothing with the signal immediately,
* other than kicking ourselves if we are running.
* It will either never be noticed, or noticed very soon.
*/
#ifdef SMP
if (TD_IS_RUNNING(td) && td != curthread)
forward_signal(td);
#endif
out:
PROC_SUNLOCK(p);
thread_unlock(td);
}
static int
sig_suspend_threads(struct thread *td, struct proc *p, int sending)
{
struct thread *td2;
int wakeup_swapper;
PROC_LOCK_ASSERT(p, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
MPASS(sending || td == curthread);
wakeup_swapper = 0;
FOREACH_THREAD_IN_PROC(p, td2) {
thread_lock(td2);
td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) &&
(td2->td_flags & TDF_SINTR)) {
if (td2->td_flags & TDF_SBDRY) {
/*
* Once a thread is asleep with
* TDF_SBDRY and without TDF_SERESTART
* or TDF_SEINTR set, it should never
* become suspended due to this check.
*/
KASSERT(!TD_IS_SUSPENDED(td2),
("thread with deferred stops suspended"));
if (TD_SBDRY_INTR(td2)) {
wakeup_swapper |= sleepq_abort(td2,
TD_SBDRY_ERRNO(td2));
continue;
}
} else if (!TD_IS_SUSPENDED(td2))
thread_suspend_one(td2);
} else if (!TD_IS_SUSPENDED(td2)) {
if (sending || td != td2)
td2->td_flags |= TDF_ASTPENDING;
#ifdef SMP
if (TD_IS_RUNNING(td2) && td2 != td)
forward_signal(td2);
#endif
}
thread_unlock(td2);
}
return (wakeup_swapper);
}
/*
* Stop the process for an event deemed interesting to the debugger. If si is
* non-NULL, this is a signal exchange; the new signal requested by the
* debugger will be returned for handling. If si is NULL, this is some other
* type of interesting event. The debugger may request a signal be delivered in
* that case as well, however it will be deferred until it can be handled.
*/
int
ptracestop(struct thread *td, int sig, ksiginfo_t *si)
{
struct proc *p = td->td_proc;
struct thread *td2;
ksiginfo_t ksi;
PROC_LOCK_ASSERT(p, MA_OWNED);
KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process"));
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
&p->p_mtx.lock_object, "Stopping for traced signal");
td->td_xsig = sig;
if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) {
td->td_dbgflags |= TDB_XSIG;
CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d",
td->td_tid, p->p_pid, td->td_dbgflags, sig);
PROC_SLOCK(p);
while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
if (P_KILLED(p)) {
/*
* Ensure that, if we've been PT_KILLed, the
* exit status reflects that. Another thread
* may also be in ptracestop(), having just
* received the SIGKILL, but this thread was
* unsuspended first.
*/
td->td_dbgflags &= ~TDB_XSIG;
td->td_xsig = SIGKILL;
p->p_ptevents = 0;
break;
}
if (p->p_flag & P_SINGLE_EXIT &&
!(td->td_dbgflags & TDB_EXIT)) {
/*
* Ignore ptrace stops except for thread exit
* events when the process exits.
*/
td->td_dbgflags &= ~TDB_XSIG;
PROC_SUNLOCK(p);
return (0);
}
/*
* Make wait(2) work. Ensure that right after the
* attach, the thread which was decided to become the
* leader of attach gets reported to the waiter.
* Otherwise, just avoid overwriting another thread's
* assignment to p_xthread. If another thread has
* already set p_xthread, the current thread will get
* a chance to report itself upon the next iteration.
*/
if ((td->td_dbgflags & TDB_FSTP) != 0 ||
((p->p_flag2 & P2_PTRACE_FSTP) == 0 &&
p->p_xthread == NULL)) {
p->p_xsig = sig;
p->p_xthread = td;
/*
* If we are on sleepqueue already,
* let sleepqueue code decide if it
* needs to go sleep after attach.
*/
if (td->td_wchan == NULL)
td->td_dbgflags &= ~TDB_FSTP;
p->p_flag2 &= ~P2_PTRACE_FSTP;
p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE;
sig_suspend_threads(td, p, 0);
}
if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
td->td_dbgflags &= ~TDB_STOPATFORK;
}
stopme:
thread_suspend_switch(td, p);
if (p->p_xthread == td)
p->p_xthread = NULL;
if (!(p->p_flag & P_TRACED))
break;
if (td->td_dbgflags & TDB_SUSPEND) {
if (p->p_flag & P_SINGLE_EXIT)
break;
goto stopme;
}
}
PROC_SUNLOCK(p);
}
if (si != NULL && sig == td->td_xsig) {
/* Parent wants us to take the original signal unchanged. */
si->ksi_flags |= KSI_HEAD;
if (sigqueue_add(&td->td_sigqueue, sig, si) != 0)
si->ksi_signo = 0;
} else if (td->td_xsig != 0) {
/*
* If parent wants us to take a new signal, then it will leave
* it in td->td_xsig; otherwise we just look for signals again.
*/
ksiginfo_init(&ksi);
ksi.ksi_signo = td->td_xsig;
ksi.ksi_flags |= KSI_PTRACE;
td2 = sigtd(p, td->td_xsig, false);
tdsendsignal(p, td2, td->td_xsig, &ksi);
if (td != td2)
return (0);
}
return (td->td_xsig);
}
static void
reschedule_signals(struct proc *p, sigset_t block, int flags)
{
struct sigacts *ps;
struct thread *td;
int sig;
bool fastblk, pslocked;
PROC_LOCK_ASSERT(p, MA_OWNED);
ps = p->p_sigacts;
pslocked = (flags & SIGPROCMASK_PS_LOCKED) != 0;
mtx_assert(&ps->ps_mtx, pslocked ? MA_OWNED : MA_NOTOWNED);
if (SIGISEMPTY(p->p_siglist))
return;
SIGSETAND(block, p->p_siglist);
fastblk = (flags & SIGPROCMASK_FASTBLK) != 0;
while ((sig = sig_ffs(&block)) != 0) {
SIGDELSET(block, sig);
td = sigtd(p, sig, fastblk);
/*
* If sigtd() selected us despite sigfastblock is
* blocking, do not activate AST or wake us, to avoid
* loop in AST handler.
*/
if (fastblk && td == curthread)
continue;
signotify(td);
if (!pslocked)
mtx_lock(&ps->ps_mtx);
if (p->p_flag & P_TRACED ||
(SIGISMEMBER(ps->ps_sigcatch, sig) &&
!SIGISMEMBER(td->td_sigmask, sig))) {
tdsigwakeup(td, sig, SIG_CATCH,
(SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR :
ERESTART));
}
if (!pslocked)
mtx_unlock(&ps->ps_mtx);
}
}
void
tdsigcleanup(struct thread *td)
{
struct proc *p;
sigset_t unblocked;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
sigqueue_flush(&td->td_sigqueue);
if (p->p_numthreads == 1)
return;
/*
* Since we cannot handle signals, notify signal post code
* about this by filling the sigmask.
*
* Also, if needed, wake up thread(s) that do not block the
* same signals as the exiting thread, since the thread might
* have been selected for delivery and woken up.
*/
SIGFILLSET(unblocked);
SIGSETNAND(unblocked, td->td_sigmask);
SIGFILLSET(td->td_sigmask);
reschedule_signals(p, unblocked, 0);
}
static int
sigdeferstop_curr_flags(int cflags)
{
MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 ||
(cflags & TDF_SBDRY) != 0);
return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART));
}
/*
* Defer the delivery of SIGSTOP for the current thread, according to
* the requested mode. Returns previous flags, which must be restored
* by sigallowstop().
*
* TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and
* cleared by the current thread, which allow the lock-less read-only
* accesses below.
*/
int
sigdeferstop_impl(int mode)
{
struct thread *td;
int cflags, nflags;
td = curthread;
cflags = sigdeferstop_curr_flags(td->td_flags);
switch (mode) {
case SIGDEFERSTOP_NOP:
nflags = cflags;
break;
case SIGDEFERSTOP_OFF:
nflags = 0;
break;
case SIGDEFERSTOP_SILENT:
nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART);
break;
case SIGDEFERSTOP_EINTR:
nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART;
break;
case SIGDEFERSTOP_ERESTART:
nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR;
break;
default:
panic("sigdeferstop: invalid mode %x", mode);
break;
}
if (cflags == nflags)
return (SIGDEFERSTOP_VAL_NCHG);
thread_lock(td);
td->td_flags = (td->td_flags & ~cflags) | nflags;
thread_unlock(td);
return (cflags);
}
/*
* Restores the STOP handling mode, typically permitting the delivery
* of SIGSTOP for the current thread. This does not immediately
* suspend if a stop was posted. Instead, the thread will suspend
* either via ast() or a subsequent interruptible sleep.
*/
void
sigallowstop_impl(int prev)
{
struct thread *td;
int cflags;
KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop"));
KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0,
("sigallowstop: incorrect previous mode %x", prev));
td = curthread;
cflags = sigdeferstop_curr_flags(td->td_flags);
if (cflags != prev) {
thread_lock(td);
td->td_flags = (td->td_flags & ~cflags) | prev;
thread_unlock(td);
}
}
/*
* If the current process has received a signal (should be caught or cause
* termination, should interrupt current syscall), return the signal number.
* Stop signals with default action are processed immediately, then cleared;
* they aren't returned. This is checked after each entry to the system for
* a syscall or trap (though this can usually be done without calling issignal
* by checking the pending signal masks in cursig.) The normal call
* sequence is
*
* while (sig = cursig(curthread))
* postsig(sig);
*/
static int
issignal(struct thread *td)
{
struct proc *p;
struct sigacts *ps;
struct sigqueue *queue;
sigset_t sigpending;
ksiginfo_t ksi;
int prop, sig;
p = td->td_proc;
ps = p->p_sigacts;
mtx_assert(&ps->ps_mtx, MA_OWNED);
PROC_LOCK_ASSERT(p, MA_OWNED);
for (;;) {
sigpending = td->td_sigqueue.sq_signals;
SIGSETOR(sigpending, p->p_sigqueue.sq_signals);
SIGSETNAND(sigpending, td->td_sigmask);
if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags &
(TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY)
SIG_STOPSIGMASK(sigpending);
if (SIGISEMPTY(sigpending)) /* no signal to send */
return (0);
/*
* Do fast sigblock if requested by usermode. Since
* we do know that there was a signal pending at this
* point, set the FAST_SIGBLOCK_PEND as indicator for
* usermode to perform a dummy call to
* FAST_SIGBLOCK_UNBLOCK, which causes immediate
* delivery of postponed pending signal.
*/
if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) {
if (td->td_sigblock_val != 0)
SIGSETNAND(sigpending, fastblock_mask);
if (SIGISEMPTY(sigpending)) {
td->td_pflags |= TDP_SIGFASTPENDING;
return (0);
}
}
if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED &&
(p->p_flag2 & P2_PTRACE_FSTP) != 0 &&
SIGISMEMBER(sigpending, SIGSTOP)) {
/*
* If debugger just attached, always consume
* SIGSTOP from ptrace(PT_ATTACH) first, to
* execute the debugger attach ritual in
* order.
*/
sig = SIGSTOP;
td->td_dbgflags |= TDB_FSTP;
} else {
sig = sig_ffs(&sigpending);
}
/*
* We should see pending but ignored signals
* only if P_TRACED was on when they were posted.
*/
if (SIGISMEMBER(ps->ps_sigignore, sig) &&
(p->p_flag & P_TRACED) == 0) {
sigqueue_delete(&td->td_sigqueue, sig);
sigqueue_delete(&p->p_sigqueue, sig);
continue;
}
if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) {
/*
* If traced, always stop.
* Remove old signal from queue before the stop.
* XXX shrug off debugger, it causes siginfo to
* be thrown away.
*/
queue = &td->td_sigqueue;
ksiginfo_init(&ksi);
if (sigqueue_get(queue, sig, &ksi) == 0) {
queue = &p->p_sigqueue;
sigqueue_get(queue, sig, &ksi);
}
td->td_si = ksi.ksi_info;
mtx_unlock(&ps->ps_mtx);
sig = ptracestop(td, sig, &ksi);
mtx_lock(&ps->ps_mtx);
td->td_si.si_signo = 0;
/*
* Keep looking if the debugger discarded or
* replaced the signal.
*/
if (sig == 0)
continue;
/*
* If the signal became masked, re-queue it.
*/
if (SIGISMEMBER(td->td_sigmask, sig)) {
ksi.ksi_flags |= KSI_HEAD;
sigqueue_add(&p->p_sigqueue, sig, &ksi);
continue;
}
/*
* If the traced bit got turned off, requeue
* the signal and go back up to the top to
* rescan signals. This ensures that p_sig*
* and p_sigact are consistent.
*/
if ((p->p_flag & P_TRACED) == 0) {
ksi.ksi_flags |= KSI_HEAD;
sigqueue_add(queue, sig, &ksi);
continue;
}
}
prop = sigprop(sig);
/*
* Decide whether the signal should be returned.
* Return the signal's number, or fall through
* to clear it from the pending mask.
*/
switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
case (intptr_t)SIG_DFL:
/*
* Don't take default actions on system processes.
*/
if (p->p_pid <= 1) {
#ifdef DIAGNOSTIC
/*
* Are you sure you want to ignore SIGSEGV
* in init? XXX
*/
printf("Process (pid %lu) got signal %d\n",
(u_long)p->p_pid, sig);
#endif
break; /* == ignore */
}
/*
* If there is a pending stop signal to process with
* default action, stop here, then clear the signal.
* Traced or exiting processes should ignore stops.
* Additionally, a member of an orphaned process group
* should ignore tty stops.
*/
if (prop & SIGPROP_STOP) {
mtx_unlock(&ps->ps_mtx);
if ((p->p_flag & (P_TRACED | P_WEXIT |
P_SINGLE_EXIT)) != 0 || ((p->p_pgrp->
pg_flags & PGRP_ORPHANED) != 0 &&
(prop & SIGPROP_TTYSTOP) != 0)) {
mtx_lock(&ps->ps_mtx);
break; /* == ignore */
}
if (TD_SBDRY_INTR(td)) {
KASSERT((td->td_flags & TDF_SBDRY) != 0,
("lost TDF_SBDRY"));
mtx_lock(&ps->ps_mtx);
return (-1);
}
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
&p->p_mtx.lock_object, "Catching SIGSTOP");
sigqueue_delete(&td->td_sigqueue, sig);
sigqueue_delete(&p->p_sigqueue, sig);
p->p_flag |= P_STOPPED_SIG;
p->p_xsig = sig;
PROC_SLOCK(p);
sig_suspend_threads(td, p, 0);
thread_suspend_switch(td, p);
PROC_SUNLOCK(p);
mtx_lock(&ps->ps_mtx);
goto next;
} else if (prop & SIGPROP_IGNORE) {
/*
* Except for SIGCONT, shouldn't get here.
* Default action is to ignore; drop it.
*/
break; /* == ignore */
} else
return (sig);
/*NOTREACHED*/
case (intptr_t)SIG_IGN:
/*
* Masking above should prevent us ever trying
* to take action on an ignored signal other
* than SIGCONT, unless process is traced.
*/
if ((prop & SIGPROP_CONT) == 0 &&
(p->p_flag & P_TRACED) == 0)
printf("issignal\n");
break; /* == ignore */
default:
/*
* This signal has an action, let
* postsig() process it.
*/
return (sig);
}
sigqueue_delete(&td->td_sigqueue, sig); /* take the signal! */
sigqueue_delete(&p->p_sigqueue, sig);
next:;
}
/* NOTREACHED */
}
void
thread_stopped(struct proc *p)
{
int n;
PROC_LOCK_ASSERT(p, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
n = p->p_suspcount;
if (p == curproc)
n++;
if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
PROC_SUNLOCK(p);
p->p_flag &= ~P_WAITED;
PROC_LOCK(p->p_pptr);
childproc_stopped(p, (p->p_flag & P_TRACED) ?
CLD_TRAPPED : CLD_STOPPED);
PROC_UNLOCK(p->p_pptr);
PROC_SLOCK(p);
}
}
/*
* Take the action for the specified signal
* from the current set of pending signals.
*/
int
postsig(int sig)
{
struct thread *td;
struct proc *p;
struct sigacts *ps;
sig_t action;
ksiginfo_t ksi;
sigset_t returnmask;
KASSERT(sig != 0, ("postsig"));
td = curthread;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
ps = p->p_sigacts;
mtx_assert(&ps->ps_mtx, MA_OWNED);
ksiginfo_init(&ksi);
if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 &&
sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0)
return (0);
ksi.ksi_signo = sig;
if (ksi.ksi_code == SI_TIMER)
itimer_accept(p, ksi.ksi_timerid, &ksi);
action = ps->ps_sigact[_SIG_IDX(sig)];
#ifdef KTRACE
if (KTRPOINT(td, KTR_PSIG))
ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
&td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code);
#endif
if (action == SIG_DFL) {
/*
* Default action, where the default is to kill
* the process. (Other cases were ignored above.)
*/
mtx_unlock(&ps->ps_mtx);
proc_td_siginfo_capture(td, &ksi.ksi_info);
sigexit(td, sig);
/* NOTREACHED */
} else {
/*
* If we get here, the signal must be caught.
*/
KASSERT(action != SIG_IGN, ("postsig action %p", action));
KASSERT(!SIGISMEMBER(td->td_sigmask, sig),
("postsig action: blocked sig %d", sig));
/*
* Set the new mask value and also defer further
* occurrences of this signal.
*
* Special case: user has done a sigsuspend. Here the
* current mask is not of interest, but rather the
* mask from before the sigsuspend is what we want
* restored after the signal processing is completed.
*/
if (td->td_pflags & TDP_OLDMASK) {
returnmask = td->td_oldsigmask;
td->td_pflags &= ~TDP_OLDMASK;
} else
returnmask = td->td_sigmask;
if (p->p_sig == sig) {
p->p_sig = 0;
}
(*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
postsig_done(sig, td, ps);
}
return (1);
}
int
sig_ast_checksusp(struct thread *td)
{
struct proc *p;
int ret;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
if ((td->td_flags & TDF_NEEDSUSPCHK) == 0)
return (0);
ret = thread_suspend_check(1);
MPASS(ret == 0 || ret == EINTR || ret == ERESTART);
return (ret);
}
int
sig_ast_needsigchk(struct thread *td)
{
struct proc *p;
struct sigacts *ps;
int ret, sig;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
if ((td->td_flags & TDF_NEEDSIGCHK) == 0)
return (0);
ps = p->p_sigacts;
mtx_lock(&ps->ps_mtx);
sig = cursig(td);
if (sig == -1) {
mtx_unlock(&ps->ps_mtx);
KASSERT((td->td_flags & TDF_SBDRY) != 0, ("lost TDF_SBDRY"));
KASSERT(TD_SBDRY_INTR(td),
("lost TDF_SERESTART of TDF_SEINTR"));
KASSERT((td->td_flags & (TDF_SEINTR | TDF_SERESTART)) !=
(TDF_SEINTR | TDF_SERESTART),
("both TDF_SEINTR and TDF_SERESTART"));
ret = TD_SBDRY_ERRNO(td);
} else if (sig != 0) {
ret = SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : ERESTART;
mtx_unlock(&ps->ps_mtx);
} else {
mtx_unlock(&ps->ps_mtx);
ret = 0;
}
/*
* Do not go into sleep if this thread was the ptrace(2)
* attach leader. cursig() consumed SIGSTOP from PT_ATTACH,
* but we usually act on the signal by interrupting sleep, and
* should do that here as well.
*/
if ((td->td_dbgflags & TDB_FSTP) != 0) {
if (ret == 0)
ret = EINTR;
td->td_dbgflags &= ~TDB_FSTP;
}
return (ret);
}
int
sig_intr(void)
{
struct thread *td;
struct proc *p;
int ret;
td = curthread;
if ((td->td_flags & (TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK)) == 0)
return (0);
p = td->td_proc;
PROC_LOCK(p);
ret = sig_ast_checksusp(td);
if (ret == 0)
ret = sig_ast_needsigchk(td);
PROC_UNLOCK(p);
return (ret);
}
void
proc_wkilled(struct proc *p)
{
PROC_LOCK_ASSERT(p, MA_OWNED);
if ((p->p_flag & P_WKILLED) == 0) {
p->p_flag |= P_WKILLED;
/*
* Notify swapper that there is a process to swap in.
* The notification is racy, at worst it would take 10
* seconds for the swapper process to notice.
*/
if ((p->p_flag & (P_INMEM | P_SWAPPINGIN)) == 0)
wakeup(&proc0);
}
}
/*
* Kill the current process for stated reason.
*/
void
killproc(struct proc *p, const char *why)
{
PROC_LOCK_ASSERT(p, MA_OWNED);
CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid,
p->p_comm);
log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n",
p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id,
p->p_ucred->cr_uid, why);
proc_wkilled(p);
kern_psignal(p, SIGKILL);
}
/*
* Force the current process to exit with the specified signal, dumping core
* if appropriate. We bypass the normal tests for masked and caught signals,
* allowing unrecoverable failures to terminate the process without changing
* signal state. Mark the accounting record with the signal termination.
* If dumping core, save the signal number for the debugger. Calls exit and
* does not return.
*/
void
sigexit(struct thread *td, int sig)
{
struct proc *p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
p->p_acflag |= AXSIG;
/*
* We must be single-threading to generate a core dump. This
* ensures that the registers in the core file are up-to-date.
* Also, the ELF dump handler assumes that the thread list doesn't
* change out from under it.
*
* XXX If another thread attempts to single-thread before us
* (e.g. via fork()), we won't get a dump at all.
*/
if ((sigprop(sig) & SIGPROP_CORE) &&
thread_single(p, SINGLE_NO_EXIT) == 0) {
p->p_sig = sig;
/*
* Log signals which would cause core dumps
* (Log as LOG_INFO to appease those who don't want
* these messages.)
* XXX : Todo, as well as euid, write out ruid too
* Note that coredump() drops proc lock.
*/
if (coredump(td) == 0)
sig |= WCOREFLAG;
if (kern_logsigexit)
log(LOG_INFO,
"pid %d (%s), jid %d, uid %d: exited on "
"signal %d%s\n", p->p_pid, p->p_comm,
p->p_ucred->cr_prison->pr_id,
td->td_ucred->cr_uid,
sig &~ WCOREFLAG,
sig & WCOREFLAG ? " (core dumped)" : "");
} else
PROC_UNLOCK(p);
exit1(td, 0, sig);
/* NOTREACHED */
}
/*
* Send queued SIGCHLD to parent when child process's state
* is changed.
*/
static void
sigparent(struct proc *p, int reason, int status)
{
PROC_LOCK_ASSERT(p, MA_OWNED);
PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
if (p->p_ksi != NULL) {
p->p_ksi->ksi_signo = SIGCHLD;
p->p_ksi->ksi_code = reason;
p->p_ksi->ksi_status = status;
p->p_ksi->ksi_pid = p->p_pid;
p->p_ksi->ksi_uid = p->p_ucred->cr_ruid;
if (KSI_ONQ(p->p_ksi))
return;
}
pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
}
static void
childproc_jobstate(struct proc *p, int reason, int sig)
{
struct sigacts *ps;
PROC_LOCK_ASSERT(p, MA_OWNED);
PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
/*
* Wake up parent sleeping in kern_wait(), also send
* SIGCHLD to parent, but SIGCHLD does not guarantee
* that parent will awake, because parent may masked
* the signal.
*/
p->p_pptr->p_flag |= P_STATCHILD;
wakeup(p->p_pptr);
ps = p->p_pptr->p_sigacts;
mtx_lock(&ps->ps_mtx);
if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
mtx_unlock(&ps->ps_mtx);
sigparent(p, reason, sig);
} else
mtx_unlock(&ps->ps_mtx);
}
void
childproc_stopped(struct proc *p, int reason)
{
childproc_jobstate(p, reason, p->p_xsig);
}
void
childproc_continued(struct proc *p)
{
childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
}
void
childproc_exited(struct proc *p)
{
int reason, status;
if (WCOREDUMP(p->p_xsig)) {
reason = CLD_DUMPED;
status = WTERMSIG(p->p_xsig);
} else if (WIFSIGNALED(p->p_xsig)) {
reason = CLD_KILLED;
status = WTERMSIG(p->p_xsig);
} else {
reason = CLD_EXITED;
status = p->p_xexit;
}
/*
* XXX avoid calling wakeup(p->p_pptr), the work is
* done in exit1().
*/
sigparent(p, reason, status);
}
#define MAX_NUM_CORE_FILES 100000
#ifndef NUM_CORE_FILES
#define NUM_CORE_FILES 5
#endif
CTASSERT(NUM_CORE_FILES >= 0 && NUM_CORE_FILES <= MAX_NUM_CORE_FILES);
static int num_cores = NUM_CORE_FILES;
static int
sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS)
{
int error;
int new_val;
new_val = num_cores;
error = sysctl_handle_int(oidp, &new_val, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (new_val > MAX_NUM_CORE_FILES)
new_val = MAX_NUM_CORE_FILES;
if (new_val < 0)
new_val = 0;
num_cores = new_val;
return (0);
}
SYSCTL_PROC(_debug, OID_AUTO, ncores,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, sizeof(int),
sysctl_debug_num_cores_check, "I",
"Maximum number of generated process corefiles while using index format");
#define GZIP_SUFFIX ".gz"
#define ZSTD_SUFFIX ".zst"
int compress_user_cores = 0;
static int
sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS)
{
int error, val;
val = compress_user_cores;
error = sysctl_handle_int(oidp, &val, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (val != 0 && !compressor_avail(val))
return (EINVAL);
compress_user_cores = val;
return (error);
}
SYSCTL_PROC(_kern, OID_AUTO, compress_user_cores,
CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 0, sizeof(int),
sysctl_compress_user_cores, "I",
"Enable compression of user corefiles ("
__XSTRING(COMPRESS_GZIP) " = gzip, "
__XSTRING(COMPRESS_ZSTD) " = zstd)");
int compress_user_cores_level = 6;
SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_level, CTLFLAG_RWTUN,
&compress_user_cores_level, 0,
"Corefile compression level");
/*
* Protect the access to corefilename[] by allproc_lock.
*/
#define corefilename_lock allproc_lock
static char corefilename[MAXPATHLEN] = {"%N.core"};
TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename));
static int
sysctl_kern_corefile(SYSCTL_HANDLER_ARGS)
{
int error;
sx_xlock(&corefilename_lock);
error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename),
req);
sx_xunlock(&corefilename_lock);
return (error);
}
SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW |
CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A",
"Process corefile name format string");
static void
vnode_close_locked(struct thread *td, struct vnode *vp)
{
VOP_UNLOCK(vp);
vn_close(vp, FWRITE, td->td_ucred, td);
}
/*
* If the core format has a %I in it, then we need to check
* for existing corefiles before defining a name.
* To do this we iterate over 0..ncores to find a
* non-existing core file name to use. If all core files are
* already used we choose the oldest one.
*/
static int
corefile_open_last(struct thread *td, char *name, int indexpos,
int indexlen, int ncores, struct vnode **vpp)
{
struct vnode *oldvp, *nextvp, *vp;
struct vattr vattr;
struct nameidata nd;
int error, i, flags, oflags, cmode;
char ch;
struct timespec lasttime;
nextvp = oldvp = NULL;
cmode = S_IRUSR | S_IWUSR;
oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
(capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
for (i = 0; i < ncores; i++) {
flags = O_CREAT | FWRITE | O_NOFOLLOW;
ch = name[indexpos + indexlen];
(void)snprintf(name + indexpos, indexlen + 1, "%.*u", indexlen,
i);
name[indexpos + indexlen] = ch;
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred,
NULL);
if (error != 0)
break;
vp = nd.ni_vp;
NDFREE(&nd, NDF_ONLY_PNBUF);
if ((flags & O_CREAT) == O_CREAT) {
nextvp = vp;
break;
}
error = VOP_GETATTR(vp, &vattr, td->td_ucred);
if (error != 0) {
vnode_close_locked(td, vp);
break;
}
if (oldvp == NULL ||
lasttime.tv_sec > vattr.va_mtime.tv_sec ||
(lasttime.tv_sec == vattr.va_mtime.tv_sec &&
lasttime.tv_nsec >= vattr.va_mtime.tv_nsec)) {
if (oldvp != NULL)
vn_close(oldvp, FWRITE, td->td_ucred, td);
oldvp = vp;
VOP_UNLOCK(oldvp);
lasttime = vattr.va_mtime;
} else {
vnode_close_locked(td, vp);
}
}
if (oldvp != NULL) {
if (nextvp == NULL) {
if ((td->td_proc->p_flag & P_SUGID) != 0) {
error = EFAULT;
vn_close(oldvp, FWRITE, td->td_ucred, td);
} else {
nextvp = oldvp;
error = vn_lock(nextvp, LK_EXCLUSIVE);
if (error != 0) {
vn_close(nextvp, FWRITE, td->td_ucred,
td);
nextvp = NULL;
}
}
} else {
vn_close(oldvp, FWRITE, td->td_ucred, td);
}
}
if (error != 0) {
if (nextvp != NULL)
vnode_close_locked(td, oldvp);
} else {
*vpp = nextvp;
}
return (error);
}
/*
* corefile_open(comm, uid, pid, td, compress, vpp, namep)
* Expand the name described in corefilename, using name, uid, and pid
* and open/create core file.
* corefilename is a printf-like string, with three format specifiers:
* %N name of process ("name")
* %P process id (pid)
* %U user id (uid)
* For example, "%N.core" is the default; they can be disabled completely
* by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
* This is controlled by the sysctl variable kern.corefile (see above).
*/
static int
corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
int compress, int signum, struct vnode **vpp, char **namep)
{
struct sbuf sb;
struct nameidata nd;
const char *format;
char *hostname, *name;
int cmode, error, flags, i, indexpos, indexlen, oflags, ncores;
hostname = NULL;
format = corefilename;
name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO);
indexlen = 0;
indexpos = -1;
ncores = num_cores;
(void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN);
sx_slock(&corefilename_lock);
for (i = 0; format[i] != '\0'; i++) {
switch (format[i]) {
case '%': /* Format character */
i++;
switch (format[i]) {
case '%':
sbuf_putc(&sb, '%');
break;
case 'H': /* hostname */
if (hostname == NULL) {
hostname = malloc(MAXHOSTNAMELEN,
M_TEMP, M_WAITOK);
}
getcredhostname(td->td_ucred, hostname,
MAXHOSTNAMELEN);
sbuf_printf(&sb, "%s", hostname);
break;
case 'I': /* autoincrementing index */
if (indexpos != -1) {
sbuf_printf(&sb, "%%I");
break;
}
indexpos = sbuf_len(&sb);
sbuf_printf(&sb, "%u", ncores - 1);
indexlen = sbuf_len(&sb) - indexpos;
break;
case 'N': /* process name */
sbuf_printf(&sb, "%s", comm);
break;
case 'P': /* process id */
sbuf_printf(&sb, "%u", pid);
break;
case 'S': /* signal number */
sbuf_printf(&sb, "%i", signum);
break;
case 'U': /* user id */
sbuf_printf(&sb, "%u", uid);
break;
default:
log(LOG_ERR,
"Unknown format character %c in "
"corename `%s'\n", format[i], format);
break;
}
break;
default:
sbuf_putc(&sb, format[i]);
break;
}
}
sx_sunlock(&corefilename_lock);
free(hostname, M_TEMP);
if (compress == COMPRESS_GZIP)
sbuf_printf(&sb, GZIP_SUFFIX);
else if (compress == COMPRESS_ZSTD)
sbuf_printf(&sb, ZSTD_SUFFIX);
if (sbuf_error(&sb) != 0) {
log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
"long\n", (long)pid, comm, (u_long)uid);
sbuf_delete(&sb);
free(name, M_TEMP);
return (ENOMEM);
}
sbuf_finish(&sb);
sbuf_delete(&sb);
if (indexpos != -1) {
error = corefile_open_last(td, name, indexpos, indexlen, ncores,
vpp);
if (error != 0) {
log(LOG_ERR,
"pid %d (%s), uid (%u): Path `%s' failed "
"on initial open test, error = %d\n",
pid, comm, uid, name, error);
}
} else {
cmode = S_IRUSR | S_IWUSR;
oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
(capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
flags = O_CREAT | FWRITE | O_NOFOLLOW;
if ((td->td_proc->p_flag & P_SUGID) != 0)
flags |= O_EXCL;
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred,
NULL);
if (error == 0) {
*vpp = nd.ni_vp;
NDFREE(&nd, NDF_ONLY_PNBUF);
}
}
if (error != 0) {
#ifdef AUDIT
audit_proc_coredump(td, name, error);
#endif
free(name, M_TEMP);
return (error);
}
*namep = name;
return (0);
}
/*
* Dump a process' core. The main routine does some
* policy checking, and creates the name of the coredump;
* then it passes on a vnode and a size limit to the process-specific
* coredump routine if there is one; if there _is not_ one, it returns
* ENOSYS; otherwise it returns the error from the process-specific routine.
*/
static int
coredump(struct thread *td)
{
struct proc *p = td->td_proc;
struct ucred *cred = td->td_ucred;
struct vnode *vp;
struct flock lf;
struct vattr vattr;
size_t fullpathsize;
int error, error1, locked;
char *name; /* name of corefile */
void *rl_cookie;
off_t limit;
char *fullpath, *freepath = NULL;
struct sbuf *sb;
PROC_LOCK_ASSERT(p, MA_OWNED);
MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) ||
(p->p_flag2 & P2_NOTRACE) != 0) {
PROC_UNLOCK(p);
return (EFAULT);
}
/*
* Note that the bulk of limit checking is done after
* the corefile is created. The exception is if the limit
* for corefiles is 0, in which case we don't bother
* creating the corefile at all. This layout means that
* a corefile is truncated instead of not being created,
* if it is larger than the limit.
*/
limit = (off_t)lim_cur(td, RLIMIT_CORE);
if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) {
PROC_UNLOCK(p);
return (EFBIG);
}
PROC_UNLOCK(p);
error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td,
compress_user_cores, p->p_sig, &vp, &name);
if (error != 0)
return (error);
/*
* Don't dump to non-regular files or files with links.
* Do not dump into system files. Effective user must own the corefile.
*/
if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 ||
vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0 ||
vattr.va_uid != cred->cr_uid) {
VOP_UNLOCK(vp);
error = EFAULT;
goto out;
}
VOP_UNLOCK(vp);
/* Postpone other writers, including core dumps of other processes. */
rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_WRLCK;
locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0);
VATTR_NULL(&vattr);
vattr.va_size = 0;
if (set_core_nodump_flag)
vattr.va_flags = UF_NODUMP;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
VOP_SETATTR(vp, &vattr, cred);
VOP_UNLOCK(vp);
PROC_LOCK(p);
p->p_acflag |= ACORE;
PROC_UNLOCK(p);
if (p->p_sysent->sv_coredump != NULL) {
error = p->p_sysent->sv_coredump(td, vp, limit, 0);
} else {
error = ENOSYS;
}
if (locked) {
lf.l_type = F_UNLCK;
VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
}
vn_rangelock_unlock(vp, rl_cookie);
/*
* Notify the userland helper that a process triggered a core dump.
* This allows the helper to run an automated debugging session.
*/
if (error != 0 || coredump_devctl == 0)
goto out;
sb = sbuf_new_auto();
if (vn_fullpath_global(p->p_textvp, &fullpath, &freepath) != 0)
goto out2;
sbuf_printf(sb, "comm=\"");
devctl_safe_quote_sb(sb, fullpath);
free(freepath, M_TEMP);
sbuf_printf(sb, "\" core=\"");
/*
* We can't lookup core file vp directly. When we're replacing a core, and
* other random times, we flush the name cache, so it will fail. Instead,
* if the path of the core is relative, add the current dir in front if it.
*/
if (name[0] != '/') {
fullpathsize = MAXPATHLEN;
freepath = malloc(fullpathsize, M_TEMP, M_WAITOK);
if (vn_getcwd(freepath, &fullpath, &fullpathsize) != 0) {
free(freepath, M_TEMP);
goto out2;
}
devctl_safe_quote_sb(sb, fullpath);
free(freepath, M_TEMP);
sbuf_putc(sb, '/');
}
devctl_safe_quote_sb(sb, name);
sbuf_printf(sb, "\"");
if (sbuf_finish(sb) == 0)
devctl_notify("kernel", "signal", "coredump", sbuf_data(sb));
out2:
sbuf_delete(sb);
out:
error1 = vn_close(vp, FWRITE, cred, td);
if (error == 0)
error = error1;
#ifdef AUDIT
audit_proc_coredump(td, name, error);
#endif
free(name, M_TEMP);
return (error);
}
/*
* Nonexistent system call-- signal process (may want to handle it). Flag
* error in case process won't see signal immediately (blocked or ignored).
*/
#ifndef _SYS_SYSPROTO_H_
struct nosys_args {
int dummy;
};
#endif
/* ARGSUSED */
int
nosys(struct thread *td, struct nosys_args *args)
{
struct proc *p;
p = td->td_proc;
PROC_LOCK(p);
tdsignal(td, SIGSYS);
PROC_UNLOCK(p);
if (kern_lognosys == 1 || kern_lognosys == 3) {
uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
td->td_sa.code);
}
if (kern_lognosys == 2 || kern_lognosys == 3 ||
(p->p_pid == 1 && (kern_lognosys & 3) == 0)) {
printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm,
td->td_sa.code);
}
return (ENOSYS);
}
/*
* Send a SIGIO or SIGURG signal to a process or process group using stored
* credentials rather than those of the current process.
*/
void
pgsigio(struct sigio **sigiop, int sig, int checkctty)
{
ksiginfo_t ksi;
struct sigio *sigio;
ksiginfo_init(&ksi);
ksi.ksi_signo = sig;
ksi.ksi_code = SI_KERNEL;
SIGIO_LOCK();
sigio = *sigiop;
if (sigio == NULL) {
SIGIO_UNLOCK();
return;
}
if (sigio->sio_pgid > 0) {
PROC_LOCK(sigio->sio_proc);
if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
kern_psignal(sigio->sio_proc, sig);
PROC_UNLOCK(sigio->sio_proc);
} else if (sigio->sio_pgid < 0) {
struct proc *p;
PGRP_LOCK(sigio->sio_pgrp);
LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
PROC_LOCK(p);
if (p->p_state == PRS_NORMAL &&
CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
(checkctty == 0 || (p->p_flag & P_CONTROLT)))
kern_psignal(p, sig);
PROC_UNLOCK(p);
}
PGRP_UNLOCK(sigio->sio_pgrp);
}
SIGIO_UNLOCK();
}
static int
filt_sigattach(struct knote *kn)
{
struct proc *p = curproc;
kn->kn_ptr.p_proc = p;
kn->kn_flags |= EV_CLEAR; /* automatically set */
knlist_add(p->p_klist, kn, 0);
return (0);
}
static void
filt_sigdetach(struct knote *kn)
{
struct proc *p = kn->kn_ptr.p_proc;
knlist_remove(p->p_klist, kn, 0);
}
/*
* signal knotes are shared with proc knotes, so we apply a mask to
* the hint in order to differentiate them from process hints. This
* could be avoided by using a signal-specific knote list, but probably
* isn't worth the trouble.
*/
static int
filt_signal(struct knote *kn, long hint)
{
if (hint & NOTE_SIGNAL) {
hint &= ~NOTE_SIGNAL;
if (kn->kn_id == hint)
kn->kn_data++;
}
return (kn->kn_data != 0);
}
struct sigacts *
sigacts_alloc(void)
{
struct sigacts *ps;
ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
refcount_init(&ps->ps_refcnt, 1);
mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
return (ps);
}
void
sigacts_free(struct sigacts *ps)
{
if (refcount_release(&ps->ps_refcnt) == 0)
return;
mtx_destroy(&ps->ps_mtx);
free(ps, M_SUBPROC);
}
struct sigacts *
sigacts_hold(struct sigacts *ps)
{
refcount_acquire(&ps->ps_refcnt);
return (ps);
}
void
sigacts_copy(struct sigacts *dest, struct sigacts *src)
{
KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
mtx_lock(&src->ps_mtx);
bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
mtx_unlock(&src->ps_mtx);
}
int
sigacts_shared(struct sigacts *ps)
{
return (ps->ps_refcnt > 1);
}
void
sig_drop_caught(struct proc *p)
{
int sig;
struct sigacts *ps;
ps = p->p_sigacts;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_assert(&ps->ps_mtx, MA_OWNED);
while (SIGNOTEMPTY(ps->ps_sigcatch)) {
sig = sig_ffs(&ps->ps_sigcatch);
sigdflt(ps, sig);
if ((sigprop(sig) & SIGPROP_IGNORE) != 0)
sigqueue_delete_proc(p, sig);
}
}
static void
sigfastblock_failed(struct thread *td, bool sendsig, bool write)
{
ksiginfo_t ksi;
/*
* Prevent further fetches and SIGSEGVs, allowing thread to
* issue syscalls despite corruption.
*/
sigfastblock_clear(td);
if (!sendsig)
return;
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGSEGV;
ksi.ksi_code = write ? SEGV_ACCERR : SEGV_MAPERR;
ksi.ksi_addr = td->td_sigblock_ptr;
trapsignal(td, &ksi);
}
static bool
sigfastblock_fetch_sig(struct thread *td, bool sendsig, uint32_t *valp)
{
uint32_t res;
if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0)
return (true);
if (fueword32((void *)td->td_sigblock_ptr, &res) == -1) {
sigfastblock_failed(td, sendsig, false);
return (false);
}
*valp = res;
td->td_sigblock_val = res & ~SIGFASTBLOCK_FLAGS;
return (true);
}
static void
sigfastblock_resched(struct thread *td, bool resched)
{
struct proc *p;
if (resched) {
p = td->td_proc;
PROC_LOCK(p);
reschedule_signals(p, td->td_sigmask, 0);
PROC_UNLOCK(p);
}
thread_lock(td);
td->td_flags |= TDF_ASTPENDING | TDF_NEEDSIGCHK;
thread_unlock(td);
}
int
sys_sigfastblock(struct thread *td, struct sigfastblock_args *uap)
{
struct proc *p;
int error, res;
uint32_t oldval;
error = 0;
p = td->td_proc;
switch (uap->cmd) {
case SIGFASTBLOCK_SETPTR:
if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) {
error = EBUSY;
break;
}
if (((uintptr_t)(uap->ptr) & (sizeof(uint32_t) - 1)) != 0) {
error = EINVAL;
break;
}
td->td_pflags |= TDP_SIGFASTBLOCK;
td->td_sigblock_ptr = uap->ptr;
break;
case SIGFASTBLOCK_UNBLOCK:
if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
error = EINVAL;
break;
}
for (;;) {
res = casueword32(td->td_sigblock_ptr,
SIGFASTBLOCK_PEND, &oldval, 0);
if (res == -1) {
error = EFAULT;
sigfastblock_failed(td, false, true);
break;
}
if (res == 0)
break;
MPASS(res == 1);
if (oldval != SIGFASTBLOCK_PEND) {
error = EBUSY;
break;
}
error = thread_check_susp(td, false);
if (error != 0)
break;
}
if (error != 0)
break;
/*
* td_sigblock_val is cleared there, but not on a
* syscall exit. The end effect is that a single
* interruptible sleep, while user sigblock word is
* set, might return EINTR or ERESTART to usermode
* without delivering signal. All further sleeps,
* until userspace clears the word and does
* sigfastblock(UNBLOCK), observe current word and no
* longer get interrupted. It is slight
* non-conformance, with alternative to have read the
* sigblock word on each syscall entry.
*/
td->td_sigblock_val = 0;
/*
* Rely on normal ast mechanism to deliver pending
* signals to current thread. But notify others about
* fake unblock.
*/
sigfastblock_resched(td, error == 0 && p->p_numthreads != 1);
break;
case SIGFASTBLOCK_UNSETPTR:
if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
error = EINVAL;
break;
}
if (!sigfastblock_fetch_sig(td, false, &oldval)) {
error = EFAULT;
break;
}
if (oldval != 0 && oldval != SIGFASTBLOCK_PEND) {
error = EBUSY;
break;
}
sigfastblock_clear(td);
break;
default:
error = EINVAL;
break;
}
return (error);
}
void
sigfastblock_clear(struct thread *td)
{
bool resched;
if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0)
return;
td->td_sigblock_val = 0;
resched = (td->td_pflags & TDP_SIGFASTPENDING) != 0 ||
SIGPENDING(td);
td->td_pflags &= ~(TDP_SIGFASTBLOCK | TDP_SIGFASTPENDING);
sigfastblock_resched(td, resched);
}
void
sigfastblock_fetch(struct thread *td)
{
uint32_t val;
(void)sigfastblock_fetch_sig(td, true, &val);
}
static void
sigfastblock_setpend1(struct thread *td)
{
int res;
uint32_t oldval;
if ((td->td_pflags & TDP_SIGFASTPENDING) == 0)
return;
res = fueword32((void *)td->td_sigblock_ptr, &oldval);
if (res == -1) {
sigfastblock_failed(td, true, false);
return;
}
for (;;) {
res = casueword32(td->td_sigblock_ptr, oldval, &oldval,
oldval | SIGFASTBLOCK_PEND);
if (res == -1) {
sigfastblock_failed(td, true, true);
return;
}
if (res == 0) {
td->td_sigblock_val = oldval & ~SIGFASTBLOCK_FLAGS;
td->td_pflags &= ~TDP_SIGFASTPENDING;
break;
}
MPASS(res == 1);
if (thread_check_susp(td, false) != 0)
break;
}
}
void
sigfastblock_setpend(struct thread *td, bool resched)
{
struct proc *p;
sigfastblock_setpend1(td);
if (resched) {
p = td->td_proc;
PROC_LOCK(p);
reschedule_signals(p, fastblock_mask, SIGPROCMASK_FASTBLK);
PROC_UNLOCK(p);
}
}
Reference in New Issue View Git Blame Copy Permalink