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freebsd-dev/sys/kern/kern_sig.c
Ed Schouten c90c9021e9 Remove even more unneeded variable assignments. 
kern_time.c:
- Unused variable `p'.

kern_thr.c:
- Variable `error' is always caught immediately, so no reason to
  initialize it. There is no way that error != 0 at the end of
  create_thread().

kern_sig.c:
- Unused variable `code'.

kern_synch.c:
- `rval' is always assigned in all different cases.

kern_rwlock.c:
- `v' is always overwritten with RW_UNLOCKED further on.

kern_malloc.c:
- `size' is always initialized with the proper value before being used.

kern_exit.c:
- `error' is always caught and returned immediately. abort2() never
  returns a non-zero value.

kern_exec.c:
- `len' is always assigned inside the if-statement right below it.

tty_info.c:
- `td' is always overwritten by FOREACH_THREAD_IN_PROC().

Found by:	LLVM's scan-build
2009-02-26 15:51:54 +00:00

3170 lines
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/*-
* 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.
* 4. 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_compat.h"
#include "opt_kdtrace.h"
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>
#include <sys/acct.h>
#include <sys/condvar.h>
#include <sys/event.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/ktrace.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/posix4.h>
#include <sys/pioctl.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 <machine/cpu.h>
#include <security/audit/audit.h>
#define ONSIG 32 /* NSIG for osig* syscalls. XXX. */
SDT_PROVIDER_DECLARE(proc);
SDT_PROBE_DEFINE(proc, kernel, , signal_send);
SDT_PROBE_ARGTYPE(proc, kernel, , signal_send, 0, "struct thread *");
SDT_PROBE_ARGTYPE(proc, kernel, , signal_send, 1, "struct proc *");
SDT_PROBE_ARGTYPE(proc, kernel, , signal_send, 2, "int");
SDT_PROBE_DEFINE(proc, kernel, , signal_clear);
SDT_PROBE_ARGTYPE(proc, kernel, , signal_clear, 0, "int");
SDT_PROBE_ARGTYPE(proc, kernel, , signal_clear, 1, "ksiginfo_t *");
SDT_PROBE_DEFINE(proc, kernel, , signal_discard);
SDT_PROBE_ARGTYPE(proc, kernel, , signal_discard, 0, "struct thread *");
SDT_PROBE_ARGTYPE(proc, kernel, , signal_discard, 1, "struct proc *");
SDT_PROBE_ARGTYPE(proc, kernel, , signal_discard, 2, "int");
static int coredump(struct thread *);
static char *expand_name(const char *, uid_t, pid_t);
static int killpg1(struct thread *td, int sig, int pgid, int all);
static int issignal(struct thread *p);
static int sigprop(int sig);
static void tdsigwakeup(struct thread *, int, sig_t, int);
static void 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, int prop);
static void sigqueue_start(void);
static uma_zone_t ksiginfo_zone = NULL;
struct filterops sig_filtops =
{ 0, filt_sigattach, filt_sigdetach, filt_signal };
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");
SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW, 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;
TUNABLE_INT("kern.sigqueue.preallocate", &preallocate_siginfo);
SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RD,
&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");
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)
int sugid_coredump;
SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
&sugid_coredump, 0, "Enable coredumping set user/group ID processes");
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");
/*
* Signal properties and actions.
* The array below categorizes the signals and their default actions
* according to the following properties:
*/
#define SA_KILL 0x01 /* terminates process by default */
#define SA_CORE 0x02 /* ditto and coredumps */
#define SA_STOP 0x04 /* suspend process */
#define SA_TTYSTOP 0x08 /* ditto, from tty */
#define SA_IGNORE 0x10 /* ignore by default */
#define SA_CONT 0x20 /* continue if suspended */
#define SA_CANTMASK 0x40 /* non-maskable, catchable */
#define SA_PROC 0x80 /* deliverable to any thread */
static int sigproptbl[NSIG] = {
SA_KILL|SA_PROC, /* SIGHUP */
SA_KILL|SA_PROC, /* SIGINT */
SA_KILL|SA_CORE|SA_PROC, /* SIGQUIT */
SA_KILL|SA_CORE, /* SIGILL */
SA_KILL|SA_CORE, /* SIGTRAP */
SA_KILL|SA_CORE, /* SIGABRT */
SA_KILL|SA_CORE|SA_PROC, /* SIGEMT */
SA_KILL|SA_CORE, /* SIGFPE */
SA_KILL|SA_PROC, /* SIGKILL */
SA_KILL|SA_CORE, /* SIGBUS */
SA_KILL|SA_CORE, /* SIGSEGV */
SA_KILL|SA_CORE, /* SIGSYS */
SA_KILL|SA_PROC, /* SIGPIPE */
SA_KILL|SA_PROC, /* SIGALRM */
SA_KILL|SA_PROC, /* SIGTERM */
SA_IGNORE|SA_PROC, /* SIGURG */
SA_STOP|SA_PROC, /* SIGSTOP */
SA_STOP|SA_TTYSTOP|SA_PROC, /* SIGTSTP */
SA_IGNORE|SA_CONT|SA_PROC, /* SIGCONT */
SA_IGNORE|SA_PROC, /* SIGCHLD */
SA_STOP|SA_TTYSTOP|SA_PROC, /* SIGTTIN */
SA_STOP|SA_TTYSTOP|SA_PROC, /* SIGTTOU */
SA_IGNORE|SA_PROC, /* SIGIO */
SA_KILL, /* SIGXCPU */
SA_KILL, /* SIGXFSZ */
SA_KILL|SA_PROC, /* SIGVTALRM */
SA_KILL|SA_PROC, /* SIGPROF */
SA_IGNORE|SA_PROC, /* SIGWINCH */
SA_IGNORE|SA_PROC, /* SIGINFO */
SA_KILL|SA_PROC, /* SIGUSR1 */
SA_KILL|SA_PROC, /* SIGUSR2 */
};
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);
}
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);
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
*/
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_kill, signo)) {
count++;
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))
SIGDELSET(sq->sq_signals, ksi->ksi_signo);
}
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"));
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) {
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;
TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link);
ksi->ksi_sigq = sq;
}
if ((si->ksi_flags & KSI_TRAP) != 0) {
if (ret != 0)
SIGADDSET(sq->sq_kill, signo);
ret = 0;
goto out_set_bit;
}
if (ret != 0)
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);
}
void
sigqueue_collect_set(sigqueue_t *sq, sigset_t *set)
{
ksiginfo_t *ksi;
KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
TAILQ_FOREACH(ksi, &sq->sq_list, ksi_link)
SIGADDSET(*set, ksi->ksi_signo);
SIGSETOR(*set, sq->sq_kill);
}
void
sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, sigset_t *setp)
{
sigset_t tmp, set;
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"));
/*
* make a copy, this allows setp to point to src or dst
* sq_signals without trouble.
*/
set = *setp;
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_signals;
SIGSETAND(tmp, set);
SIGSETOR(dst->sq_signals, tmp);
SIGSETNAND(src->sq_signals, tmp);
/* Finally, rescan src queue and set pending bits for it */
sigqueue_collect_set(src, &src->sq_signals);
}
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);
}
void
sigqueue_delete_set(sigqueue_t *sq, 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_signals, *set);
/* Finally, rescan queue and set pending bits for it */
sigqueue_collect_set(sq, &sq->sq_signals);
}
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 */
void
sigqueue_delete_set_proc(struct proc *p, 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);
}
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 process p, the current
* process, 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)
{
struct proc *p;
sigset_t set;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
/*
* If our mask changed we may have to move signal that were
* previously masked by all threads to our sigqueue.
*/
set = p->p_sigqueue.sq_signals;
SIGSETNAND(set, td->td_sigmask);
if (! SIGISEMPTY(set))
sigqueue_move_set(&p->p_sigqueue, &td->td_sigqueue, &set);
if (SIGPENDING(td)) {
thread_lock(td);
td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
thread_unlock(td);
}
}
int
sigonstack(size_t sp)
{
struct thread *td = curthread;
return ((td->td_pflags & TDP_ALTSTACK) ?
#if defined(COMPAT_43)
((td->td_sigstk.ss_size == 0) ?
(td->td_sigstk.ss_flags & SS_ONSTACK) :
((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size))
#else
((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size)
#endif
: 0);
}
static __inline int
sigprop(int sig)
{
if (sig > 0 && sig < NSIG)
return (sigproptbl[_SIG_IDX(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);
}
/*
* kern_sigaction
* sigaction
* freebsd4_sigaction
* osigaction
*/
int
kern_sigaction(td, sig, act, oact, flags)
struct thread *td;
register int sig;
struct sigaction *act, *oact;
int flags;
{
struct sigacts *ps;
struct proc *p = td->td_proc;
if (!_SIG_VALID(sig))
return (EINVAL);
PROC_LOCK(p);
ps = p->p_sigacts;
mtx_lock(&ps->ps_mtx);
if (oact) {
oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
oact->sa_flags = 0;
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 (act->sa_flags & 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 (!(act->sa_flags & SA_RESTART))
SIGADDSET(ps->ps_sigintr, sig);
else
SIGDELSET(ps->ps_sigintr, sig);
if (act->sa_flags & SA_ONSTACK)
SIGADDSET(ps->ps_sigonstack, sig);
else
SIGDELSET(ps->ps_sigonstack, sig);
if (act->sa_flags & SA_RESETHAND)
SIGADDSET(ps->ps_sigreset, sig);
else
SIGDELSET(ps->ps_sigreset, sig);
if (act->sa_flags & 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) & SA_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
sigaction(td, uap)
struct thread *td;
register struct sigaction_args *uap;
{
struct sigaction act, oact;
register 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(td, uap)
struct thread *td;
register struct freebsd4_sigaction_args *uap;
{
struct sigaction act, oact;
register 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(td, uap)
struct thread *td;
register struct osigaction_args *uap;
{
struct osigaction sa;
struct sigaction nsa, osa;
register 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(td, uap)
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(p)
struct proc *p;
{
register 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) & SA_IGNORE && i != SIGCONT)
SIGADDSET(ps->ps_sigignore, i);
mtx_unlock(&ps->ps_mtx);
PROC_UNLOCK(p);
}
/*
* Reset signals for an exec of the specified process.
*/
void
execsigs(struct proc *p)
{
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);
td = FIRST_THREAD_IN_PROC(p);
ps = p->p_sigacts;
mtx_lock(&ps->ps_mtx);
while (SIGNOTEMPTY(ps->ps_sigcatch)) {
sig = sig_ffs(&ps->ps_sigcatch);
SIGDELSET(ps->ps_sigcatch, sig);
if (sigprop(sig) & SA_IGNORE) {
if (sig != SIGCONT)
SIGADDSET(ps->ps_sigignore, sig);
sigqueue_delete_proc(p, sig);
}
ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
}
/*
* Reset stack state to the user stack.
* Clear set of signals caught on the signal stack.
*/
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(td, how, set, oset, old)
struct thread *td;
int how;
sigset_t *set, *oset;
int old;
{
int error;
PROC_LOCK(td->td_proc);
if (oset != NULL)
*oset = td->td_sigmask;
error = 0;
if (set != NULL) {
switch (how) {
case SIG_BLOCK:
SIG_CANTMASK(*set);
SIGSETOR(td->td_sigmask, *set);
break;
case SIG_UNBLOCK:
SIGSETNAND(td->td_sigmask, *set);
signotify(td);
break;
case SIG_SETMASK:
SIG_CANTMASK(*set);
if (old)
SIGSETLO(td->td_sigmask, *set);
else
td->td_sigmask = *set;
signotify(td);
break;
default:
error = EINVAL;
break;
}
}
PROC_UNLOCK(td->td_proc);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct sigprocmask_args {
int how;
const sigset_t *set;
sigset_t *oset;
};
#endif
int
sigprocmask(td, uap)
register 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(td, uap)
register 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
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 == 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
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
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);
}
int
kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi,
struct timespec *timeout)
{
struct sigacts *ps;
sigset_t savedmask;
struct proc *p;
int error, sig, hz, i, timevalid = 0;
struct timespec rts, ets, ts;
struct timeval tv;
p = td->td_proc;
error = 0;
sig = 0;
ets.tv_sec = 0;
ets.tv_nsec = 0;
SIG_CANTMASK(waitset);
PROC_LOCK(p);
ps = p->p_sigacts;
savedmask = td->td_sigmask;
if (timeout) {
if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
timevalid = 1;
getnanouptime(&rts);
ets = rts;
timespecadd(&ets, timeout);
}
}
restart:
for (i = 1; i <= _SIG_MAXSIG; ++i) {
if (!SIGISMEMBER(waitset, i))
continue;
if (!SIGISMEMBER(td->td_sigqueue.sq_signals, i)) {
if (SIGISMEMBER(p->p_sigqueue.sq_signals, i)) {
sigqueue_move(&p->p_sigqueue,
&td->td_sigqueue, i);
} else
continue;
}
SIGFILLSET(td->td_sigmask);
SIG_CANTMASK(td->td_sigmask);
SIGDELSET(td->td_sigmask, i);
mtx_lock(&ps->ps_mtx);
sig = cursig(td);
mtx_unlock(&ps->ps_mtx);
if (sig)
goto out;
else {
/*
* Because cursig() may have stopped current thread,
* after it is resumed, things may have already been
* changed, it should rescan any pending signals.
*/
goto restart;
}
}
if (error)
goto out;
/*
* POSIX says this must be checked after looking for pending
* signals.
*/
if (timeout) {
if (!timevalid) {
error = EINVAL;
goto out;
}
getnanouptime(&rts);
if (timespeccmp(&rts, &ets, >=)) {
error = EAGAIN;
goto out;
}
ts = ets;
timespecsub(&ts, &rts);
TIMESPEC_TO_TIMEVAL(&tv, &ts);
hz = tvtohz(&tv);
} else
hz = 0;
td->td_sigmask = savedmask;
SIGSETNAND(td->td_sigmask, waitset);
signotify(td);
error = msleep(&ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", hz);
if (timeout) {
if (error == ERESTART) {
/* timeout can not be restarted. */
error = EINTR;
} else if (error == EAGAIN) {
/* will calculate timeout by ourself. */
error = 0;
}
}
goto restart;
out:
td->td_sigmask = savedmask;
signotify(td);
if (sig) {
ksiginfo_init(ksi);
sigqueue_get(&td->td_sigqueue, sig, ksi);
ksi->ksi_signo = sig;
SDT_PROBE(proc, kernel, , signal_clear, sig, ksi, 0, 0, 0);
if (ksi->ksi_code == SI_TIMER)
itimer_accept(p, ksi->ksi_timerid, ksi);
error = 0;
#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, 0);
}
#endif
if (sig == SIGKILL)
sigexit(td, sig);
}
PROC_UNLOCK(p);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct sigpending_args {
sigset_t *set;
};
#endif
int
sigpending(td, uap)
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(td, uap)
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(td, uap)
struct thread *td;
register struct osigvec_args *uap;
{
struct sigvec vec;
struct sigaction nsa, osa;
register 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(td, uap)
register struct thread *td;
struct osigblock_args *uap;
{
struct proc *p = td->td_proc;
sigset_t set;
OSIG2SIG(uap->mask, set);
SIG_CANTMASK(set);
PROC_LOCK(p);
SIG2OSIG(td->td_sigmask, td->td_retval[0]);
SIGSETOR(td->td_sigmask, set);
PROC_UNLOCK(p);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct osigsetmask_args {
int mask;
};
#endif
int
osigsetmask(td, uap)
struct thread *td;
struct osigsetmask_args *uap;
{
struct proc *p = td->td_proc;
sigset_t set;
OSIG2SIG(uap->mask, set);
SIG_CANTMASK(set);
PROC_LOCK(p);
SIG2OSIG(td->td_sigmask, td->td_retval[0]);
SIGSETLO(td->td_sigmask, set);
signotify(td);
PROC_UNLOCK(p);
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
sigsuspend(td, uap)
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;
/*
* 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);
td->td_oldsigmask = td->td_sigmask;
td->td_pflags |= TDP_OLDMASK;
SIG_CANTMASK(mask);
td->td_sigmask = mask;
signotify(td);
while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause", 0) == 0)
/* void */;
PROC_UNLOCK(p);
/* always return EINTR rather than ERESTART... */
return (EINTR);
}
#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(td, uap)
struct thread *td;
struct osigsuspend_args *uap;
{
struct proc *p = td->td_proc;
sigset_t mask;
PROC_LOCK(p);
td->td_oldsigmask = td->td_sigmask;
td->td_pflags |= TDP_OLDMASK;
OSIG2SIG(uap->mask, mask);
SIG_CANTMASK(mask);
SIGSETLO(td->td_sigmask, mask);
signotify(td);
while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "opause", 0) == 0)
/* void */;
PROC_UNLOCK(p);
/* always return EINTR rather than ERESTART... */
return (EINTR);
}
#endif /* COMPAT_43 */
#if defined(COMPAT_43)
#ifndef _SYS_SYSPROTO_H_
struct osigstack_args {
struct sigstack *nss;
struct sigstack *oss;
};
#endif
/* ARGSUSED */
int
osigstack(td, uap)
struct thread *td;
register 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
sigaltstack(td, uap)
struct thread *td;
register 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);
}
/*
* Common code for kill process group/broadcast kill.
* cp is calling process.
*/
static int
killpg1(td, sig, pgid, all)
register struct thread *td;
int sig, pgid, all;
{
register struct proc *p;
struct pgrp *pgrp;
int nfound = 0;
if (all) {
/*
* broadcast
*/
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
p == td->td_proc || p->p_state == PRS_NEW) {
PROC_UNLOCK(p);
continue;
}
if (p_cansignal(td, p, sig) == 0) {
nfound++;
if (sig)
psignal(p, sig);
}
PROC_UNLOCK(p);
}
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) {
PROC_LOCK(p);
if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
p->p_state == PRS_NEW ) {
PROC_UNLOCK(p);
continue;
}
if (p_cansignal(td, p, sig) == 0) {
nfound++;
if (sig)
psignal(p, sig);
}
PROC_UNLOCK(p);
}
PGRP_UNLOCK(pgrp);
}
return (nfound ? 0 : ESRCH);
}
#ifndef _SYS_SYSPROTO_H_
struct kill_args {
int pid;
int signum;
};
#endif
/* ARGSUSED */
int
kill(td, uap)
register struct thread *td;
register struct kill_args *uap;
{
register struct proc *p;
int error;
AUDIT_ARG(signum, uap->signum);
AUDIT_ARG(pid, uap->pid);
if ((u_int)uap->signum > _SIG_MAXSIG)
return (EINVAL);
if (uap->pid > 0) {
/* kill single process */
if ((p = pfind(uap->pid)) == NULL) {
if ((p = zpfind(uap->pid)) == NULL)
return (ESRCH);
}
AUDIT_ARG(process, p);
error = p_cansignal(td, p, uap->signum);
if (error == 0 && uap->signum)
psignal(p, uap->signum);
PROC_UNLOCK(p);
return (error);
}
switch (uap->pid) {
case -1: /* broadcast signal */
return (killpg1(td, uap->signum, 0, 1));
case 0: /* signal own process group */
return (killpg1(td, uap->signum, 0, 0));
default: /* negative explicit process group */
return (killpg1(td, uap->signum, -uap->pid, 0));
}
/* NOTREACHED */
}
#if defined(COMPAT_43)
#ifndef _SYS_SYSPROTO_H_
struct okillpg_args {
int pgid;
int signum;
};
#endif
/* ARGSUSED */
int
okillpg(td, uap)
struct thread *td;
register struct okillpg_args *uap;
{
AUDIT_ARG(signum, uap->signum);
AUDIT_ARG(pid, uap->pgid);
if ((u_int)uap->signum > _SIG_MAXSIG)
return (EINVAL);
return (killpg1(td, uap->signum, uap->pgid, 0));
}
#endif /* COMPAT_43 */
#ifndef _SYS_SYSPROTO_H_
struct sigqueue_args {
pid_t pid;
int signum;
/* union sigval */ void *value;
};
#endif
int
sigqueue(struct thread *td, struct sigqueue_args *uap)
{
ksiginfo_t ksi;
struct proc *p;
int error;
if ((u_int)uap->signum > _SIG_MAXSIG)
return (EINVAL);
/*
* Specification says sigqueue can only send signal to
* single process.
*/
if (uap->pid <= 0)
return (EINVAL);
if ((p = pfind(uap->pid)) == NULL) {
if ((p = zpfind(uap->pid)) == NULL)
return (ESRCH);
}
error = p_cansignal(td, p, uap->signum);
if (error == 0 && uap->signum != 0) {
ksiginfo_init(&ksi);
ksi.ksi_signo = uap->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.sival_ptr = uap->value;
error = tdsignal(p, NULL, ksi.ksi_signo, &ksi);
}
PROC_UNLOCK(p);
return (error);
}
/*
* Send a signal to a process group.
*/
void
gsignal(pgid, sig)
int pgid, sig;
{
struct pgrp *pgrp;
if (pgid != 0) {
sx_slock(&proctree_lock);
pgrp = pgfind(pgid);
sx_sunlock(&proctree_lock);
if (pgrp != NULL) {
pgsignal(pgrp, sig, 0);
PGRP_UNLOCK(pgrp);
}
}
}
/*
* Send a signal to a process group. If checktty is 1,
* limit to members which have a controlling terminal.
*/
void
pgsignal(pgrp, sig, checkctty)
struct pgrp *pgrp;
int sig, checkctty;
{
register struct proc *p;
if (pgrp) {
PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
PROC_LOCK(p);
if (checkctty == 0 || p->p_flag & P_CONTROLT)
psignal(p, sig);
PROC_UNLOCK(p);
}
}
}
/*
* 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;
int sig;
int code;
p = td->td_proc;
sig = ksi->ksi_signo;
code = ksi->ksi_code;
KASSERT(_SIG_VALID(sig), ("invalid signal"));
PROC_LOCK(p);
ps = p->p_sigacts;
mtx_lock(&ps->ps_mtx);
if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
!SIGISMEMBER(td->td_sigmask, sig)) {
td->td_ru.ru_nsignals++;
#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);
SIGSETOR(td->td_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
if (!SIGISMEMBER(ps->ps_signodefer, sig))
SIGADDSET(td->td_sigmask, sig);
if (SIGISMEMBER(ps->ps_sigreset, sig)) {
/*
* See kern_sigaction() for origin of this code.
*/
SIGDELSET(ps->ps_sigcatch, sig);
if (sig != SIGCONT &&
sigprop(sig) & SA_IGNORE)
SIGADDSET(ps->ps_sigignore, sig);
ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
}
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(td->td_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;
}
mtx_unlock(&ps->ps_mtx);
p->p_code = code; /* XXX for core dump/debugger */
p->p_sig = sig; /* XXX to verify code */
tdsignal(p, td, sig, ksi);
}
PROC_UNLOCK(p);
}
static struct thread *
sigtd(struct proc *p, int sig, int prop)
{
struct thread *td, *signal_td;
PROC_LOCK_ASSERT(p, MA_OWNED);
/*
* Check if current thread can handle the signal without
* switching conetxt to another thread.
*/
if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig))
return (curthread);
signal_td = NULL;
FOREACH_THREAD_IN_PROC(p, td) {
if (!SIGISMEMBER(td->td_sigmask, sig)) {
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
psignal(struct proc *p, int sig)
{
(void) tdsignal(p, NULL, sig, NULL);
}
int
psignal_event(struct proc *p, struct sigevent *sigev, ksiginfo_t *ksi)
{
struct thread *td = NULL;
PROC_LOCK_ASSERT(p, MA_OWNED);
KASSERT(!KSI_ONQ(ksi), ("psignal_event: ksi on queue"));
/*
* ksi_code and other fields should be set before
* calling this function.
*/
ksi->ksi_signo = sigev->sigev_signo;
ksi->ksi_value = sigev->sigev_value;
if (sigev->sigev_notify == SIGEV_THREAD_ID) {
td = thread_find(p, sigev->sigev_notify_thread_id);
if (td == NULL)
return (ESRCH);
}
return (tdsignal(p, td, ksi->ksi_signo, ksi));
}
int
tdsignal(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;
PROC_LOCK_ASSERT(p, MA_OWNED);
if (!_SIG_VALID(sig))
panic("tdsignal(): invalid signal %d", sig);
KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("tdsignal: ksi on queue"));
/*
* 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 the signal is blocked and not destined for this thread, then
* assign it to the process so that we can find it later in the first
* thread that unblocks it. Otherwise, assign it to this thread now.
*/
if (td == NULL) {
td = sigtd(p, sig, prop);
if (SIGISMEMBER(td->td_sigmask, sig))
sigqueue = &p->p_sigqueue;
else
sigqueue = &td->td_sigqueue;
} else {
KASSERT(td->td_proc == p, ("invalid thread"));
sigqueue = &td->td_sigqueue;
}
SDT_PROBE(proc, kernel, , signal_send, td, p, sig, 0, 0 );
/*
* 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_PROBE(proc, kernel, , signal_discard, ps, td, sig, 0, 0 );
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 & SA_CONT)
sigqueue_delete_stopmask_proc(p);
else if (prop & SA_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 & SA_TTYSTOP) &&
(p->p_pgrp->pg_jobc == 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 & SA_CONT) && (p->p_flag & P_STOPPED_SIG)))
return (ret);
/*
* SIGKILL: Remove procfs STOPEVENTs.
*/
if (sig == SIGKILL) {
/* from procfs_ioctl.c: PIOCBIC */
p->p_stops = 0;
/* from procfs_ioctl.c: PIOCCONT */
p->p_step = 0;
wakeup(&p->p_step);
}
/*
* 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 immediatly, such as
* waking up threads so that they can cross the user boundary.
* We try do the per-process part here.
*/
if (P_SHOULDSTOP(p)) {
/*
* The process is in stopped mode. All the threads should be
* either winding down or already on the suspended queue.
*/
if (p->p_flag & P_TRACED) {
/*
* The traced process is already stopped,
* so no further action is necessary.
* No signal can restart us.
*/
goto out;
}
if (sig == SIGKILL) {
/*
* SIGKILL sets process running.
* It will die elsewhere.
* All threads must be restarted.
*/
p->p_flag &= ~P_STOPPED_SIG;
goto runfast;
}
if (prop & SA_CONT) {
/*
* 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_xstat = 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 & SA_STOP) {
/*
* 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().
*/
wakeup_swapper = 0;
PROC_SLOCK(p);
thread_lock(td);
if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR))
wakeup_swapper = sleepq_abort(td, intrval);
thread_unlock(td);
PROC_SUNLOCK(p);
if (wakeup_swapper)
kick_proc0();
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 & SA_STOP) {
if (p->p_flag & P_PPWAIT)
goto out;
p->p_flag |= P_STOPPED_SIG;
p->p_xstat = sig;
PROC_SLOCK(p);
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_xstat);
} 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);
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;
register int prop;
int wakeup_swapper;
wakeup_swapper = 0;
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.
*/
if (action == SIG_DFL && (prop & SA_KILL) && td->td_priority > PUSER)
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 & SA_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;
}
/*
* Give low priority threads a better chance to run.
*/
if (td->td_priority > PUSER)
sched_prio(td, PUSER);
wakeup_swapper = sleepq_abort(td, intrval);
} else {
/*
* 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);
if (wakeup_swapper)
kick_proc0();
}
static void
sig_suspend_threads(struct thread *td, struct proc *p, int sending)
{
struct thread *td2;
PROC_LOCK_ASSERT(p, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
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) &&
!TD_IS_SUSPENDED(td2)) {
thread_suspend_one(td2);
} else {
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);
}
}
int
ptracestop(struct thread *td, int sig)
{
struct proc *p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
&p->p_mtx.lock_object, "Stopping for traced signal");
td->td_dbgflags |= TDB_XSIG;
td->td_xsig = sig;
PROC_SLOCK(p);
while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
if (p->p_flag & P_SINGLE_EXIT) {
td->td_dbgflags &= ~TDB_XSIG;
PROC_SUNLOCK(p);
return (sig);
}
/*
* Just make wait() to work, the last stopped thread
* will win.
*/
p->p_xstat = sig;
p->p_xthread = td;
p->p_flag |= (P_STOPPED_SIG|P_STOPPED_TRACE);
sig_suspend_threads(td, p, 0);
stopme:
thread_suspend_switch(td);
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);
return (td->td_xsig);
}
/*
* 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(td)
struct thread *td;
{
struct proc *p;
struct sigacts *ps;
sigset_t sigpending;
int sig, prop, newsig;
p = td->td_proc;
ps = p->p_sigacts;
mtx_assert(&ps->ps_mtx, MA_OWNED);
PROC_LOCK_ASSERT(p, MA_OWNED);
for (;;) {
int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
sigpending = td->td_sigqueue.sq_signals;
SIGSETNAND(sigpending, td->td_sigmask);
if (p->p_flag & P_PPWAIT)
SIG_STOPSIGMASK(sigpending);
if (SIGISEMPTY(sigpending)) /* no signal to send */
return (0);
sig = sig_ffs(&sigpending);
if (p->p_stops & S_SIG) {
mtx_unlock(&ps->ps_mtx);
stopevent(p, S_SIG, sig);
mtx_lock(&ps->ps_mtx);
}
/*
* We should see pending but ignored signals
* only if P_TRACED was on when they were posted.
*/
if (SIGISMEMBER(ps->ps_sigignore, sig) && (traced == 0)) {
sigqueue_delete(&td->td_sigqueue, sig);
continue;
}
if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) {
/*
* If traced, always stop.
*/
mtx_unlock(&ps->ps_mtx);
newsig = ptracestop(td, sig);
mtx_lock(&ps->ps_mtx);
if (sig != newsig) {
ksiginfo_t ksi;
/*
* clear old signal.
* XXX shrug off debugger, it causes siginfo to
* be thrown away.
*/
sigqueue_get(&td->td_sigqueue, sig, &ksi);
/*
* If parent wants us to take the signal,
* then it will leave it in p->p_xstat;
* otherwise we just look for signals again.
*/
if (newsig == 0)
continue;
sig = newsig;
/*
* Put the new signal into td_sigqueue. If the
* signal is being masked, look for other signals.
*/
SIGADDSET(td->td_sigqueue.sq_signals, sig);
if (SIGISMEMBER(td->td_sigmask, sig))
continue;
signotify(td);
}
/*
* If the traced bit got turned off, 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)
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. However,
* if process is member of an orphaned
* process group, ignore tty stop signals.
*/
if (prop & SA_STOP) {
if (p->p_flag & P_TRACED ||
(p->p_pgrp->pg_jobc == 0 &&
prop & SA_TTYSTOP))
break; /* == ignore */
mtx_unlock(&ps->ps_mtx);
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
&p->p_mtx.lock_object, "Catching SIGSTOP");
p->p_flag |= P_STOPPED_SIG;
p->p_xstat = sig;
PROC_SLOCK(p);
sig_suspend_threads(td, p, 0);
thread_suspend_switch(td);
PROC_SUNLOCK(p);
mtx_lock(&ps->ps_mtx);
break;
} else if (prop & SA_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 & SA_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! */
}
/* 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.
*/
void
postsig(sig)
register int sig;
{
struct thread *td = curthread;
register struct proc *p = td->td_proc;
struct sigacts *ps;
sig_t action;
ksiginfo_t ksi;
sigset_t returnmask;
KASSERT(sig != 0, ("postsig"));
PROC_LOCK_ASSERT(p, MA_OWNED);
ps = p->p_sigacts;
mtx_assert(&ps->ps_mtx, MA_OWNED);
ksiginfo_init(&ksi);
sigqueue_get(&td->td_sigqueue, sig, &ksi);
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, 0);
#endif
if (p->p_stops & S_SIG) {
mtx_unlock(&ps->ps_mtx);
stopevent(p, S_SIG, sig);
mtx_lock(&ps->ps_mtx);
}
if (action == SIG_DFL) {
/*
* Default action, where the default is to kill
* the process. (Other cases were ignored above.)
*/
mtx_unlock(&ps->ps_mtx);
sigexit(td, sig);
/* NOTREACHED */
} else {
/*
* If we get here, the signal must be caught.
*/
KASSERT(action != SIG_IGN && !SIGISMEMBER(td->td_sigmask, sig),
("postsig action"));
/*
* 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;
SIGSETOR(td->td_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
if (!SIGISMEMBER(ps->ps_signodefer, sig))
SIGADDSET(td->td_sigmask, sig);
if (SIGISMEMBER(ps->ps_sigreset, sig)) {
/*
* See kern_sigaction() for origin of this code.
*/
SIGDELSET(ps->ps_sigcatch, sig);
if (sig != SIGCONT &&
sigprop(sig) & SA_IGNORE)
SIGADDSET(ps->ps_sigignore, sig);
ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
}
td->td_ru.ru_nsignals++;
if (p->p_sig == sig) {
p->p_code = 0;
p->p_sig = 0;
}
(*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
}
}
/*
* Kill the current process for stated reason.
*/
void
killproc(p, why)
struct proc *p;
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), uid %d, was killed: %s\n", p->p_pid, p->p_comm,
p->p_ucred ? p->p_ucred->cr_uid : -1, why);
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(td, sig)
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) & SA_CORE) && (thread_single(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), uid %d: exited on signal %d%s\n",
p->p_pid, p->p_comm,
td->td_ucred ? td->td_ucred->cr_uid : -1,
sig &~ WCOREFLAG,
sig & WCOREFLAG ? " (core dumped)" : "");
} else
PROC_UNLOCK(p);
exit1(td, W_EXITCODE(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;
}
tdsignal(p->p_pptr, NULL, SIGCHLD, p->p_ksi);
}
static void
childproc_jobstate(struct proc *p, int reason, int status)
{
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, status);
} else
mtx_unlock(&ps->ps_mtx);
}
void
childproc_stopped(struct proc *p, int reason)
{
childproc_jobstate(p, reason, p->p_xstat);
}
void
childproc_continued(struct proc *p)
{
childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
}
void
childproc_exited(struct proc *p)
{
int reason;
int status = p->p_xstat; /* convert to int */
reason = CLD_EXITED;
if (WCOREDUMP(status))
reason = CLD_DUMPED;
else if (WIFSIGNALED(status))
reason = CLD_KILLED;
/*
* XXX avoid calling wakeup(p->p_pptr), the work is
* done in exit1().
*/
sigparent(p, reason, status);
}
static char corefilename[MAXPATHLEN] = {"%N.core"};
SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
sizeof(corefilename), "process corefile name format string");
/*
* expand_name(name, uid, pid)
* Expand the name described in corefilename, using name, uid, and pid.
* 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 char *
expand_name(name, uid, pid)
const char *name;
uid_t uid;
pid_t pid;
{
struct sbuf sb;
const char *format;
char *temp;
size_t i;
format = corefilename;
temp = malloc(MAXPATHLEN, M_TEMP, M_NOWAIT | M_ZERO);
if (temp == NULL)
return (NULL);
(void)sbuf_new(&sb, temp, MAXPATHLEN, SBUF_FIXEDLEN);
for (i = 0; format[i]; i++) {
switch (format[i]) {
case '%': /* Format character */
i++;
switch (format[i]) {
case '%':
sbuf_putc(&sb, '%');
break;
case 'N': /* process name */
sbuf_printf(&sb, "%s", name);
break;
case 'P': /* process id */
sbuf_printf(&sb, "%u", pid);
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;
default:
sbuf_putc(&sb, format[i]);
}
}
if (sbuf_overflowed(&sb)) {
sbuf_delete(&sb);
log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
"long\n", (long)pid, name, (u_long)uid);
free(temp, M_TEMP);
return (NULL);
}
sbuf_finish(&sb);
sbuf_delete(&sb);
return (temp);
}
/*
* 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;
register struct vnode *vp;
register struct ucred *cred = td->td_ucred;
struct flock lf;
struct nameidata nd;
struct vattr vattr;
int error, error1, flags, locked;
struct mount *mp;
char *name; /* name of corefile */
off_t limit;
int vfslocked;
PROC_LOCK_ASSERT(p, MA_OWNED);
MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
_STOPEVENT(p, S_CORE, 0);
name = expand_name(p->p_comm, td->td_ucred->cr_uid, p->p_pid);
if (name == NULL) {
PROC_UNLOCK(p);
#ifdef AUDIT
audit_proc_coredump(td, NULL, EINVAL);
#endif
return (EINVAL);
}
if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) {
PROC_UNLOCK(p);
#ifdef AUDIT
audit_proc_coredump(td, name, EFAULT);
#endif
free(name, M_TEMP);
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(p, RLIMIT_CORE);
PROC_UNLOCK(p);
if (limit == 0) {
#ifdef AUDIT
audit_proc_coredump(td, name, EFBIG);
#endif
free(name, M_TEMP);
return (EFBIG);
}
restart:
NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE, UIO_SYSSPACE, name, td);
flags = O_CREAT | FWRITE | O_NOFOLLOW;
error = vn_open(&nd, &flags, S_IRUSR | S_IWUSR, NULL);
if (error) {
#ifdef AUDIT
audit_proc_coredump(td, name, error);
#endif
free(name, M_TEMP);
return (error);
}
vfslocked = NDHASGIANT(&nd);
NDFREE(&nd, NDF_ONLY_PNBUF);
vp = nd.ni_vp;
/* Don't dump to non-regular files or files with links. */
if (vp->v_type != VREG ||
VOP_GETATTR(vp, &vattr, cred) || vattr.va_nlink != 1) {
VOP_UNLOCK(vp, 0);
error = EFAULT;
goto close;
}
VOP_UNLOCK(vp, 0);
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);
if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
lf.l_type = F_UNLCK;
if (locked)
VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
if ((error = vn_close(vp, FWRITE, cred, td)) != 0)
goto out;
if ((error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH)) != 0)
goto out;
VFS_UNLOCK_GIANT(vfslocked);
goto restart;
}
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_LEASE(vp, td, cred, LEASE_WRITE);
VOP_SETATTR(vp, &vattr, cred);
VOP_UNLOCK(vp, 0);
vn_finished_write(mp);
PROC_LOCK(p);
p->p_acflag |= ACORE;
PROC_UNLOCK(p);
error = p->p_sysent->sv_coredump ?
p->p_sysent->sv_coredump(td, vp, limit) :
ENOSYS;
if (locked) {
lf.l_type = F_UNLCK;
VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
}
close:
error1 = vn_close(vp, FWRITE, cred, td);
if (error == 0)
error = error1;
out:
#ifdef AUDIT
audit_proc_coredump(td, name, error);
#endif
free(name, M_TEMP);
VFS_UNLOCK_GIANT(vfslocked);
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(td, args)
struct thread *td;
struct nosys_args *args;
{
struct proc *p = td->td_proc;
PROC_LOCK(p);
psignal(p, SIGSYS);
PROC_UNLOCK(p);
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(sigiop, sig, checkctty)
struct sigio **sigiop;
int sig, checkctty;
{
struct sigio *sigio;
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))
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 (CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
(checkctty == 0 || (p->p_flag & P_CONTROLT)))
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);
ps->ps_refcnt = 1;
mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
return (ps);
}
void
sigacts_free(struct sigacts *ps)
{
mtx_lock(&ps->ps_mtx);
ps->ps_refcnt--;
if (ps->ps_refcnt == 0) {
mtx_destroy(&ps->ps_mtx);
free(ps, M_SUBPROC);
} else
mtx_unlock(&ps->ps_mtx);
}
struct sigacts *
sigacts_hold(struct sigacts *ps)
{
mtx_lock(&ps->ps_mtx);
ps->ps_refcnt++;
mtx_unlock(&ps->ps_mtx);
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)
{
int shared;
mtx_lock(&ps->ps_mtx);
shared = ps->ps_refcnt > 1;
mtx_unlock(&ps->ps_mtx);
return (shared);
}
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