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freebsd-skq/sys/kern/kern_sig.c
Konstantin Belousov 513320c0f1 sigfastblock_setpend(): do not set PEND user flag unless TDP_SIGFASTPENDING is set. 
User pending bit should not be set if kernel did not noted a pending signal.

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D28089
2021-01-12 12:43:34 +02:00

4254 lines
102 KiB
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/*-
* 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;
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;
/*
* 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);
}
}
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