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38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
39 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $
40 * $DragonFly: src/sys/kern/kern_sig.c,v 1.70 2007/02/22 15:48:55 corecode Exp $
43 #include "opt_ktrace.h"
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/sysproto.h>
49 #include <sys/signalvar.h>
50 #include <sys/resourcevar.h>
51 #include <sys/vnode.h>
52 #include <sys/event.h>
54 #include <sys/nlookup.h>
55 #include <sys/pioctl.h>
56 #include <sys/systm.h>
58 #include <sys/fcntl.h>
61 #include <sys/ktrace.h>
62 #include <sys/syslog.h>
64 #include <sys/sysent.h>
65 #include <sys/sysctl.h>
66 #include <sys/malloc.h>
67 #include <sys/interrupt.h>
68 #include <sys/unistd.h>
69 #include <sys/kern_syscall.h>
70 #include <sys/vkernel.h>
71 #include <sys/thread2.h>
73 #include <machine/cpu.h>
74 #include <machine/smp.h>
76 static int coredump(struct lwp *, int);
77 static char *expand_name(const char *, uid_t, pid_t);
78 static int dokillpg(int sig, int pgid, int all);
79 static int sig_ffs(sigset_t *set);
80 static int sigprop(int sig);
82 static void signotify_remote(void *arg);
84 static int kern_sigtimedwait(sigset_t set, siginfo_t *info,
85 struct timespec *timeout);
87 static int filt_sigattach(struct knote *kn);
88 static void filt_sigdetach(struct knote *kn);
89 static int filt_signal(struct knote *kn, long hint);
91 struct filterops sig_filtops =
92 { 0, filt_sigattach, filt_sigdetach, filt_signal };
94 static int kern_logsigexit = 1;
95 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
97 "Log processes quitting on abnormal signals to syslog(3)");
100 * Can process p, with pcred pc, send the signal sig to process q?
102 #define CANSIGNAL(q, sig) \
103 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \
104 ((sig) == SIGCONT && (q)->p_session == curproc->p_session))
107 * Policy -- Can real uid ruid with ucred uc send a signal to process q?
109 #define CANSIGIO(ruid, uc, q) \
110 ((uc)->cr_uid == 0 || \
111 (ruid) == (q)->p_ucred->cr_ruid || \
112 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \
113 (ruid) == (q)->p_ucred->cr_uid || \
114 (uc)->cr_uid == (q)->p_ucred->cr_uid)
117 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
118 &sugid_coredump, 0, "Enable coredumping set user/group ID processes");
120 static int do_coredump = 1;
121 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
122 &do_coredump, 0, "Enable/Disable coredumps");
125 * Signal properties and actions.
126 * The array below categorizes the signals and their default actions
127 * according to the following properties:
129 #define SA_KILL 0x01 /* terminates process by default */
130 #define SA_CORE 0x02 /* ditto and coredumps */
131 #define SA_STOP 0x04 /* suspend process */
132 #define SA_TTYSTOP 0x08 /* ditto, from tty */
133 #define SA_IGNORE 0x10 /* ignore by default */
134 #define SA_CONT 0x20 /* continue if suspended */
135 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
136 #define SA_CKPT 0x80 /* checkpoint process */
139 static int sigproptbl[NSIG] = {
140 SA_KILL, /* SIGHUP */
141 SA_KILL, /* SIGINT */
142 SA_KILL|SA_CORE, /* SIGQUIT */
143 SA_KILL|SA_CORE, /* SIGILL */
144 SA_KILL|SA_CORE, /* SIGTRAP */
145 SA_KILL|SA_CORE, /* SIGABRT */
146 SA_KILL|SA_CORE, /* SIGEMT */
147 SA_KILL|SA_CORE, /* SIGFPE */
148 SA_KILL, /* SIGKILL */
149 SA_KILL|SA_CORE, /* SIGBUS */
150 SA_KILL|SA_CORE, /* SIGSEGV */
151 SA_KILL|SA_CORE, /* SIGSYS */
152 SA_KILL, /* SIGPIPE */
153 SA_KILL, /* SIGALRM */
154 SA_KILL, /* SIGTERM */
155 SA_IGNORE, /* SIGURG */
156 SA_STOP, /* SIGSTOP */
157 SA_STOP|SA_TTYSTOP, /* SIGTSTP */
158 SA_IGNORE|SA_CONT, /* SIGCONT */
159 SA_IGNORE, /* SIGCHLD */
160 SA_STOP|SA_TTYSTOP, /* SIGTTIN */
161 SA_STOP|SA_TTYSTOP, /* SIGTTOU */
162 SA_IGNORE, /* SIGIO */
163 SA_KILL, /* SIGXCPU */
164 SA_KILL, /* SIGXFSZ */
165 SA_KILL, /* SIGVTALRM */
166 SA_KILL, /* SIGPROF */
167 SA_IGNORE, /* SIGWINCH */
168 SA_IGNORE, /* SIGINFO */
169 SA_KILL, /* SIGUSR1 */
170 SA_KILL, /* SIGUSR2 */
171 SA_IGNORE, /* SIGTHR */
172 SA_CKPT, /* SIGCKPT */
173 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */
211 if (sig > 0 && sig < NSIG)
212 return (sigproptbl[_SIG_IDX(sig)]);
217 sig_ffs(sigset_t *set)
221 for (i = 0; i < _SIG_WORDS; i++)
223 return (ffs(set->__bits[i]) + (i * 32));
228 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact)
230 struct thread *td = curthread;
231 struct proc *p = td->td_proc;
233 struct sigacts *ps = p->p_sigacts;
235 if (sig <= 0 || sig > _SIG_MAXSIG)
239 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
240 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
242 if (SIGISMEMBER(ps->ps_sigonstack, sig))
243 oact->sa_flags |= SA_ONSTACK;
244 if (!SIGISMEMBER(ps->ps_sigintr, sig))
245 oact->sa_flags |= SA_RESTART;
246 if (SIGISMEMBER(ps->ps_sigreset, sig))
247 oact->sa_flags |= SA_RESETHAND;
248 if (SIGISMEMBER(ps->ps_signodefer, sig))
249 oact->sa_flags |= SA_NODEFER;
250 if (SIGISMEMBER(ps->ps_siginfo, sig))
251 oact->sa_flags |= SA_SIGINFO;
252 if (SIGISMEMBER(ps->ps_sigmailbox, sig))
253 oact->sa_flags |= SA_MAILBOX;
254 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP)
255 oact->sa_flags |= SA_NOCLDSTOP;
256 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT)
257 oact->sa_flags |= SA_NOCLDWAIT;
261 * Check for invalid requests. KILL and STOP cannot be
264 if (sig == SIGKILL || sig == SIGSTOP) {
265 if (act->sa_handler != SIG_DFL)
268 /* (not needed, SIG_DFL forces action to occur) */
269 if (act->sa_flags & SA_MAILBOX)
275 * Change setting atomically.
279 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
280 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
281 if (act->sa_flags & SA_SIGINFO) {
282 ps->ps_sigact[_SIG_IDX(sig)] =
283 (__sighandler_t *)act->sa_sigaction;
284 SIGADDSET(ps->ps_siginfo, sig);
286 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
287 SIGDELSET(ps->ps_siginfo, sig);
289 if (!(act->sa_flags & SA_RESTART))
290 SIGADDSET(ps->ps_sigintr, sig);
292 SIGDELSET(ps->ps_sigintr, sig);
293 if (act->sa_flags & SA_ONSTACK)
294 SIGADDSET(ps->ps_sigonstack, sig);
296 SIGDELSET(ps->ps_sigonstack, sig);
297 if (act->sa_flags & SA_RESETHAND)
298 SIGADDSET(ps->ps_sigreset, sig);
300 SIGDELSET(ps->ps_sigreset, sig);
301 if (act->sa_flags & SA_NODEFER)
302 SIGADDSET(ps->ps_signodefer, sig);
304 SIGDELSET(ps->ps_signodefer, sig);
305 if (act->sa_flags & SA_MAILBOX)
306 SIGADDSET(ps->ps_sigmailbox, sig);
308 SIGDELSET(ps->ps_sigmailbox, sig);
309 if (sig == SIGCHLD) {
310 if (act->sa_flags & SA_NOCLDSTOP)
311 p->p_procsig->ps_flag |= PS_NOCLDSTOP;
313 p->p_procsig->ps_flag &= ~PS_NOCLDSTOP;
314 if (act->sa_flags & SA_NOCLDWAIT) {
316 * Paranoia: since SA_NOCLDWAIT is implemented
317 * by reparenting the dying child to PID 1 (and
318 * trust it to reap the zombie), PID 1 itself
319 * is forbidden to set SA_NOCLDWAIT.
322 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
324 p->p_procsig->ps_flag |= PS_NOCLDWAIT;
326 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
330 * Set bit in p_sigignore for signals that are set to SIG_IGN,
331 * and for signals set to SIG_DFL where the default is to
332 * ignore. However, don't put SIGCONT in p_sigignore, as we
333 * have to restart the process.
335 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
336 (sigprop(sig) & SA_IGNORE &&
337 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
338 /* never to be seen again */
339 SIGDELSET(p->p_siglist, sig);
341 * Remove the signal also from the thread lists.
343 FOREACH_LWP_IN_PROC(lp, p) {
344 SIGDELSET(lp->lwp_siglist, sig);
347 /* easier in ksignal */
348 SIGADDSET(p->p_sigignore, sig);
349 SIGDELSET(p->p_sigcatch, sig);
351 SIGDELSET(p->p_sigignore, sig);
352 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
353 SIGDELSET(p->p_sigcatch, sig);
355 SIGADDSET(p->p_sigcatch, sig);
364 sys_sigaction(struct sigaction_args *uap)
366 struct sigaction act, oact;
367 struct sigaction *actp, *oactp;
370 actp = (uap->act != NULL) ? &act : NULL;
371 oactp = (uap->oact != NULL) ? &oact : NULL;
373 error = copyin(uap->act, actp, sizeof(act));
377 error = kern_sigaction(uap->sig, actp, oactp);
378 if (oactp && !error) {
379 error = copyout(oactp, uap->oact, sizeof(oact));
385 * Initialize signal state for process 0;
386 * set to ignore signals that are ignored by default.
389 siginit(struct proc *p)
393 for (i = 1; i <= NSIG; i++)
394 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
395 SIGADDSET(p->p_sigignore, i);
399 * Reset signals for an exec of the specified process.
402 execsigs(struct proc *p)
404 struct sigacts *ps = p->p_sigacts;
408 lp = ONLY_LWP_IN_PROC(p);
411 * Reset caught signals. Held signals remain held
412 * through p_sigmask (unless they were caught,
413 * and are now ignored by default).
415 while (SIGNOTEMPTY(p->p_sigcatch)) {
416 sig = sig_ffs(&p->p_sigcatch);
417 SIGDELSET(p->p_sigcatch, sig);
418 if (sigprop(sig) & SA_IGNORE) {
420 SIGADDSET(p->p_sigignore, sig);
421 SIGDELSET(p->p_siglist, sig);
422 SIGDELSET(lp->lwp_siglist, sig);
424 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
428 * Reset stack state to the user stack.
429 * Clear set of signals caught on the signal stack.
431 lp->lwp_sigstk.ss_flags = SS_DISABLE;
432 lp->lwp_sigstk.ss_size = 0;
433 lp->lwp_sigstk.ss_sp = 0;
434 lp->lwp_flag &= ~LWP_ALTSTACK;
436 * Reset no zombies if child dies flag as Solaris does.
438 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
442 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
444 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
448 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
450 struct thread *td = curthread;
451 struct lwp *lp = td->td_lwp;
455 *oset = lp->lwp_sigmask;
462 SIGSETOR(lp->lwp_sigmask, *set);
465 SIGSETNAND(lp->lwp_sigmask, *set);
469 lp->lwp_sigmask = *set;
480 * sigprocmask() - MP SAFE
483 sys_sigprocmask(struct sigprocmask_args *uap)
486 sigset_t *setp, *osetp;
489 setp = (uap->set != NULL) ? &set : NULL;
490 osetp = (uap->oset != NULL) ? &oset : NULL;
492 error = copyin(uap->set, setp, sizeof(set));
496 error = kern_sigprocmask(uap->how, setp, osetp);
497 if (osetp && !error) {
498 error = copyout(osetp, uap->oset, sizeof(oset));
504 kern_sigpending(struct __sigset *set)
506 struct lwp *lp = curthread->td_lwp;
508 *set = lwp_sigpend(lp);
514 sys_sigpending(struct sigpending_args *uap)
519 error = kern_sigpending(&set);
522 error = copyout(&set, uap->set, sizeof(set));
527 * Suspend process until signal, providing mask to be set
531 kern_sigsuspend(struct __sigset *set)
533 struct thread *td = curthread;
534 struct lwp *lp = td->td_lwp;
535 struct proc *p = td->td_proc;
536 struct sigacts *ps = p->p_sigacts;
539 * When returning from sigsuspend, we want
540 * the old mask to be restored after the
541 * signal handler has finished. Thus, we
542 * save it here and mark the sigacts structure
545 lp->lwp_oldsigmask = lp->lwp_sigmask;
546 lp->lwp_flag |= LWP_OLDMASK;
549 lp->lwp_sigmask = *set;
550 while (tsleep(ps, PCATCH, "pause", 0) == 0)
552 /* always return EINTR rather than ERESTART... */
557 * Note nonstandard calling convention: libc stub passes mask, not
558 * pointer, to save a copyin.
561 sys_sigsuspend(struct sigsuspend_args *uap)
566 error = copyin(uap->sigmask, &mask, sizeof(mask));
570 error = kern_sigsuspend(&mask);
576 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss)
578 struct thread *td = curthread;
579 struct lwp *lp = td->td_lwp;
580 struct proc *p = td->td_proc;
582 if ((lp->lwp_flag & LWP_ALTSTACK) == 0)
583 lp->lwp_sigstk.ss_flags |= SS_DISABLE;
586 *oss = lp->lwp_sigstk;
589 if (ss->ss_flags & SS_DISABLE) {
590 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK)
592 lp->lwp_flag &= ~LWP_ALTSTACK;
593 lp->lwp_sigstk.ss_flags = ss->ss_flags;
595 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
597 lp->lwp_flag |= LWP_ALTSTACK;
598 lp->lwp_sigstk = *ss;
606 sys_sigaltstack(struct sigaltstack_args *uap)
612 error = copyin(uap->ss, &ss, sizeof(ss));
617 error = kern_sigaltstack(uap->ss ? &ss : NULL,
618 uap->oss ? &oss : NULL);
620 if (error == 0 && uap->oss)
621 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
626 * Common code for kill process group/broadcast kill.
627 * cp is calling process.
634 static int killpg_all_callback(struct proc *p, void *data);
637 dokillpg(int sig, int pgid, int all)
639 struct killpg_info info;
640 struct proc *cp = curproc;
651 allproc_scan(killpg_all_callback, &info);
655 * zero pgid means send to my process group.
663 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
664 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
666 p->p_stat == SZOMB ||
667 (p->p_flag & P_SYSTEM) ||
668 !CANSIGNAL(p, sig)) {
675 lockmgr(&pgrp->pg_lock, LK_RELEASE);
677 return (info.nfound ? 0 : ESRCH);
681 killpg_all_callback(struct proc *p, void *data)
683 struct killpg_info *info = data;
685 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) ||
686 p == curproc || !CANSIGNAL(p, info->sig)) {
691 ksignal(p, info->sig);
696 kern_kill(int sig, int pid)
698 struct thread *td = curthread;
699 struct proc *p = td->td_proc;
701 if ((u_int)sig > _SIG_MAXSIG)
704 /* kill single process */
705 if ((p = pfind(pid)) == NULL)
707 if (!CANSIGNAL(p, sig))
714 case -1: /* broadcast signal */
715 return (dokillpg(sig, 0, 1));
716 case 0: /* signal own process group */
717 return (dokillpg(sig, 0, 0));
718 default: /* negative explicit process group */
719 return (dokillpg(sig, -pid, 0));
725 sys_kill(struct kill_args *uap)
729 error = kern_kill(uap->signum, uap->pid);
735 * Send a signal to a process group.
738 gsignal(int pgid, int sig)
742 if (pgid && (pgrp = pgfind(pgid)))
743 pgsignal(pgrp, sig, 0);
747 * Send a signal to a process group. If checktty is 1,
748 * limit to members which have a controlling terminal.
750 * pg_lock interlocks against a fork that might be in progress, to
751 * ensure that the new child process picks up the signal.
754 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
759 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
760 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
761 if (checkctty == 0 || p->p_flag & P_CONTROLT)
764 lockmgr(&pgrp->pg_lock, LK_RELEASE);
769 * Send a signal caused by a trap to the current process.
770 * If it will be caught immediately, deliver it with correct code.
771 * Otherwise, post it normally.
774 trapsignal(struct lwp *lp, int sig, u_long code)
776 struct proc *p = lp->lwp_proc;
777 struct sigacts *ps = p->p_sigacts;
780 * If we are a virtual kernel running an emulated user process
781 * context, switch back to the virtual kernel context before
782 * trying to post the signal.
784 if (p->p_vkernel && p->p_vkernel->vk_current) {
785 struct trapframe *tf = curthread->td_lwp->lwp_md.md_regs;
791 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
792 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
793 lp->lwp_ru.ru_nsignals++;
795 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
796 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)],
797 &lp->lwp_sigmask, code);
799 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
800 &lp->lwp_sigmask, code);
801 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
802 if (!SIGISMEMBER(ps->ps_signodefer, sig))
803 SIGADDSET(lp->lwp_sigmask, sig);
804 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
806 * See kern_sigaction() for origin of this code.
808 SIGDELSET(p->p_sigcatch, sig);
809 if (sig != SIGCONT &&
810 sigprop(sig) & SA_IGNORE)
811 SIGADDSET(p->p_sigignore, sig);
812 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
815 lp->lwp_code = code; /* XXX for core dump/debugger */
816 lp->lwp_sig = sig; /* XXX to verify code */
822 * Find a suitable lwp to deliver the signal to.
824 * Returns NULL if all lwps hold the signal blocked.
827 find_lwp_for_signal(struct proc *p, int sig)
830 struct lwp *run, *sleep, *stop;
833 * If the running/preempted thread belongs to the proc to which
834 * the signal is being delivered and this thread does not block
835 * the signal, then we can avoid a context switch by delivering
836 * the signal to this thread, because it will return to userland
839 lp = lwkt_preempted_proc();
840 if (lp != NULL && lp->lwp_proc == p && !SIGISMEMBER(lp->lwp_sigmask, sig))
843 run = sleep = stop = NULL;
844 FOREACH_LWP_IN_PROC(lp, p) {
846 * If the signal is being blocked by the lwp, then this
847 * lwp is not eligible for receiving the signal.
849 if (SIGISMEMBER(lp->lwp_sigmask, sig))
852 switch (lp->lwp_stat) {
862 if (lp->lwp_flag & LWP_SINTR)
870 else if (sleep != NULL)
877 * Send the signal to the process. If the signal has an action, the action
878 * is usually performed by the target process rather than the caller; we add
879 * the signal to the set of pending signals for the process.
882 * o When a stop signal is sent to a sleeping process that takes the
883 * default action, the process is stopped without awakening it.
884 * o SIGCONT restarts stopped processes (or puts them back to sleep)
885 * regardless of the signal action (eg, blocked or ignored).
887 * Other ignored signals are discarded immediately.
890 ksignal(struct proc *p, int sig)
896 if (sig > _SIG_MAXSIG || sig <= 0) {
897 kprintf("ksignal: signal %d\n", sig);
898 panic("ksignal signal number");
902 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
908 * If proc is traced, always give parent a chance;
909 * if signal event is tracked by procfs, give *that*
912 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
916 * If the signal is being ignored,
917 * then we forget about it immediately.
918 * (Note: we don't set SIGCONT in p_sigignore,
919 * and if it is set to SIG_IGN,
920 * action will be SIG_DFL here.)
922 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT))
924 if (SIGISMEMBER(p->p_sigcatch, sig))
931 * If continuing, clear any pending STOP signals.
934 SIG_STOPSIGMASK(p->p_siglist);
936 if (prop & SA_STOP) {
938 * If sending a tty stop signal to a member of an orphaned
939 * process group, discard the signal here if the action
940 * is default; don't stop the process below if sleeping,
941 * and don't clear any pending SIGCONT.
943 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
947 SIG_CONTSIGMASK(p->p_siglist);
952 if (p->p_stat == SSTOP) {
954 * Nobody can handle this signal, so add it to the process
957 SIGADDSET(p->p_siglist, sig);
960 * If the process is stopped and is being traced, then no
961 * further action is necessary.
963 if (p->p_flag & P_TRACED)
967 * If the process is stopped and receives a KILL signal,
968 * make the process runnable.
970 if (sig == SIGKILL) {
976 * If the process is stopped and receives a CONT signal,
977 * then try to make the process runnable again.
979 if (prop & SA_CONT) {
981 * If SIGCONT is default (or ignored), we continue the
982 * process but don't leave the signal in p_siglist, as
983 * it has no further action. If SIGCONT is held, we
984 * continue the process and leave the signal in
985 * p_siglist. If the process catches SIGCONT, let it
986 * handle the signal itself.
988 /* XXX what if the signal is being held blocked? */
989 if (action == SIG_DFL)
990 SIGDELSET(p->p_siglist, sig);
992 if (action == SIG_CATCH)
998 * If the process is stopped and receives another STOP
999 * signal, we do not need to stop it again. If we did
1000 * the shell could get confused.
1002 * However, if the current/preempted lwp is part of the
1003 * process receiving the signal, we need to keep it,
1004 * so that this lwp can stop in issignal() later, as
1005 * we don't want to wait until it reaches userret!
1007 if (prop & SA_STOP) {
1008 lp = lwkt_preempted_proc();
1009 if (lp == NULL || lp->lwp_proc != p)
1010 SIGDELSET(p->p_siglist, sig);
1014 * Otherwise the process is stopped and it received some
1015 * signal, which does not change its stopped state.
1016 * Just exit, as soon as the process continues, it will
1017 * process the signal.
1023 /* else not stopped */
1026 lp = find_lwp_for_signal(p, sig);
1029 * If lp == NULL, there is no thread available which does
1030 * not block the signal. Defer further processing for this signal.
1031 * Add the signal to the process pending list.
1034 SIGADDSET(p->p_siglist, sig);
1037 /* else we have a lwp to deliver the signal to */
1039 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1040 (p->p_flag & P_TRACED) == 0) {
1045 * If the process receives a STOP signal which indeed needs to
1046 * stop the process, do so. If the process chose to catch the
1047 * signal, it will be treated like any other signal.
1049 if ((prop & SA_STOP) && action == SIG_DFL) {
1051 * If a child holding parent blocked, stopping
1052 * could cause deadlock. Take no action at this
1055 if (p->p_flag & P_PPWAIT) {
1056 SIGADDSET(p->p_siglist, sig);
1061 * Do not actually try to manipulate the process, but simply
1062 * stop it. Lwps will stop as soon as they safely can.
1070 * If it is a CONT signal with default action, just ignore it.
1072 if ((prop & SA_CONT) && action == SIG_DFL)
1076 * Mark signal pending at this specific thread.
1078 SIGADDSET(lp->lwp_siglist, sig);
1080 if (lp->lwp_stat == LSSLEEP) {
1082 * Thread is in tsleep.
1086 * If the thread is sleeping uninterruptibly
1087 * we can't interrupt the sleep... the signal will
1088 * be noticed when the lwp returns through
1089 * trap() or syscall().
1091 if ((lp->lwp_flag & LWP_SINTR) == 0)
1095 * Otherwise the signal can interrupt the sleep.
1097 * If the process is traced, the lwp will handle the
1098 * tracing in issignal() when it returns to userland.
1101 * Make runnable and break out of any tsleep as well.
1103 lp->lwp_flag |= LWP_BREAKTSLEEP;
1107 * Otherwise the thread is running
1109 * LSRUN does nothing with the signal, other than kicking
1110 * ourselves if we are running.
1111 * SZOMB and SIDL mean that it will either never be noticed,
1112 * or noticed very soon.
1114 * Note that lwp_thread may be NULL or may not be completely
1115 * initialized if the process is in the SIDL or SZOMB state.
1117 * For SMP we may have to forward the request to another cpu.
1118 * YYY the MP lock prevents the target process from moving
1119 * to another cpu, see kern/kern_switch.c
1121 * If the target thread is waiting on its message port,
1122 * wakeup the target thread so it can check (or ignore)
1123 * the new signal. YYY needs cleanup.
1125 if (lp == lwkt_preempted_proc()) {
1127 } else if (lp->lwp_stat == LSRUN) {
1128 struct thread *td = lp->lwp_thread;
1131 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x",
1132 p->p_pid, lp->lwp_tid, lp->lwp_stat,
1133 p->p_flag, lp->lwp_flag));
1136 if (td->td_gd != mycpu)
1137 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1140 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1151 * This function is called via an IPI. We will be in a critical section but
1152 * the MP lock will NOT be held. Also note that by the time the ipi message
1153 * gets to us the process 'p' (arg) may no longer be scheduled or even valid.
1156 signotify_remote(void *arg)
1158 struct lwp *lp = arg;
1160 if (lp == lwkt_preempted_proc()) {
1163 struct thread *td = lp->lwp_thread;
1164 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1172 proc_stop(struct proc *p, int notify)
1176 p->p_flag &= ~P_WAITED;
1179 (notify && (p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0))
1180 ksignal(p->p_pptr, SIGCHLD);
1184 proc_unstop(struct proc *p)
1186 struct lwp *lp = FIRST_LWP_IN_PROC(p); /* XXX lwp */
1188 p->p_stat = SACTIVE;
1193 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1195 sigset_t savedmask, set;
1196 struct proc *p = curproc;
1197 struct lwp *lp = curthread->td_lwp;
1198 int error, sig, hz, timevalid = 0;
1199 struct timespec rts, ets, ts;
1204 SIG_CANTMASK(waitset);
1205 savedmask = lp->lwp_sigmask;
1208 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1209 timeout->tv_nsec < 1000000000) {
1211 getnanouptime(&rts);
1213 timespecadd(&ets, timeout);
1218 set = lwp_sigpend(lp);
1219 SIGSETAND(set, waitset);
1220 if ((sig = sig_ffs(&set)) != 0) {
1221 SIGFILLSET(lp->lwp_sigmask);
1222 SIGDELSET(lp->lwp_sigmask, sig);
1223 SIG_CANTMASK(lp->lwp_sigmask);
1226 * It may be a STOP signal, in the case, issignal
1227 * returns 0, because we may stop there, and new
1228 * signal can come in, we should restart if we got
1238 * Previous checking got nothing, and we retried but still
1239 * got nothing, we should return the error status.
1245 * POSIX says this must be checked after looking for pending
1253 getnanouptime(&rts);
1254 if (timespeccmp(&rts, &ets, >=)) {
1259 timespecsub(&ts, &rts);
1260 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1261 hz = tvtohz_high(&tv);
1265 lp->lwp_sigmask = savedmask;
1266 SIGSETNAND(lp->lwp_sigmask, waitset);
1267 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1269 if (error == ERESTART) {
1270 /* can not restart a timeout wait. */
1272 } else if (error == EAGAIN) {
1273 /* will calculate timeout by ourself. */
1280 lp->lwp_sigmask = savedmask;
1283 bzero(info, sizeof(*info));
1284 info->si_signo = sig;
1285 lwp_delsig(lp, sig); /* take the signal! */
1294 sys_sigtimedwait(struct sigtimedwait_args *uap)
1297 struct timespec *timeout;
1303 error = copyin(uap->timeout, &ts, sizeof(ts));
1310 error = copyin(uap->set, &set, sizeof(set));
1313 error = kern_sigtimedwait(set, &info, timeout);
1317 error = copyout(&info, uap->info, sizeof(info));
1318 /* Repost if we got an error. */
1320 ksignal(curproc, info.si_signo);
1322 uap->sysmsg_result = info.si_signo;
1327 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1333 error = copyin(uap->set, &set, sizeof(set));
1336 error = kern_sigtimedwait(set, &info, NULL);
1340 error = copyout(&info, uap->info, sizeof(info));
1341 /* Repost if we got an error. */
1343 ksignal(curproc, info.si_signo);
1345 uap->sysmsg_result = info.si_signo;
1350 * If the current process has received a signal that would interrupt a
1351 * system call, return EINTR or ERESTART as appropriate.
1354 iscaught(struct lwp *lp)
1356 struct proc *p = lp->lwp_proc;
1360 if ((sig = CURSIG(lp)) != 0) {
1361 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1366 return(EWOULDBLOCK);
1370 * If the current process has received a signal (should be caught or cause
1371 * termination, should interrupt current syscall), return the signal number.
1372 * Stop signals with default action are processed immediately, then cleared;
1373 * they aren't returned. This is checked after each entry to the system for
1374 * a syscall or trap (though this can usually be done without calling issignal
1375 * by checking the pending signal masks in the CURSIG macro.) The normal call
1378 * This routine is called via CURSIG/__cursig and the MP lock might not be
1379 * held. Obtain the MP lock for the duration of the operation.
1381 * while (sig = CURSIG(curproc))
1385 issignal(struct lwp *lp)
1387 struct proc *p = lp->lwp_proc;
1393 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1395 mask = lwp_sigpend(lp);
1396 SIGSETNAND(mask, lp->lwp_sigmask);
1397 if (p->p_flag & P_PPWAIT)
1398 SIG_STOPSIGMASK(mask);
1399 if (SIGISEMPTY(mask)) { /* no signal to send */
1403 sig = sig_ffs(&mask);
1405 STOPEVENT(p, S_SIG, sig);
1408 * We should see pending but ignored signals
1409 * only if P_TRACED was on when they were posted.
1411 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1412 lwp_delsig(lp, sig);
1415 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1417 * If traced, always stop, and stay stopped until
1418 * released by the parent.
1420 * NOTE: SSTOP may get cleared during the loop,
1421 * but we do not re-notify the parent if we have
1422 * to loop several times waiting for the parent
1423 * to let us continue.
1425 * XXX not sure if this is still true
1431 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1434 * If parent wants us to take the signal,
1435 * then it will leave it in p->p_xstat;
1436 * otherwise we just look for signals again.
1438 lwp_delsig(lp, sig); /* clear old signal */
1444 * Put the new signal into p_siglist. If the
1445 * signal is being masked, look for other signals.
1447 * XXX lwp might need a call to ksignal()
1449 /* XXX should run via ksignal? */
1450 SIGADDSET(p->p_siglist, sig);
1451 if (SIGISMEMBER(lp->lwp_sigmask, sig))
1455 * If the traced bit got turned off, go back up
1456 * to the top to rescan signals. This ensures
1457 * that p_sig* and ps_sigact are consistent.
1459 if ((p->p_flag & P_TRACED) == 0)
1463 prop = sigprop(sig);
1466 * Decide whether the signal should be returned.
1467 * Return the signal's number, or fall through
1468 * to clear it from the pending mask.
1470 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1473 * Don't take default actions on system processes.
1475 if (p->p_pid <= 1) {
1478 * Are you sure you want to ignore SIGSEGV
1481 kprintf("Process (pid %lu) got signal %d\n",
1482 (u_long)p->p_pid, sig);
1484 break; /* == ignore */
1488 * Handle the in-kernel checkpoint action
1490 if (prop & SA_CKPT) {
1491 checkpoint_signal_handler(lp);
1496 * If there is a pending stop signal to process
1497 * with default action, stop here,
1498 * then clear the signal. However,
1499 * if process is member of an orphaned
1500 * process group, ignore tty stop signals.
1502 if (prop & SA_STOP) {
1503 if (p->p_flag & P_TRACED ||
1504 (p->p_pgrp->pg_jobc == 0 &&
1506 break; /* == ignore */
1507 while (p->p_stat == SSTOP) {
1511 } else if (prop & SA_IGNORE) {
1513 * Except for SIGCONT, shouldn't get here.
1514 * Default action is to ignore; drop it.
1516 break; /* == ignore */
1526 * Masking above should prevent us ever trying
1527 * to take action on an ignored signal other
1528 * than SIGCONT, unless process is traced.
1530 if ((prop & SA_CONT) == 0 &&
1531 (p->p_flag & P_TRACED) == 0)
1532 kprintf("issignal\n");
1533 break; /* == ignore */
1537 * This signal has an action, let
1538 * postsig() process it.
1543 lwp_delsig(lp, sig); /* take the signal! */
1549 * Take the action for the specified signal
1550 * from the current set of pending signals.
1555 struct lwp *lp = curthread->td_lwp;
1556 struct proc *p = lp->lwp_proc;
1557 struct sigacts *ps = p->p_sigacts;
1559 sigset_t returnmask;
1562 KASSERT(sig != 0, ("postsig"));
1565 * If we are a virtual kernel running an emulated user process
1566 * context, switch back to the virtual kernel context before
1567 * trying to post the signal.
1569 if (p->p_vkernel && p->p_vkernel->vk_current) {
1570 struct trapframe *tf = curthread->td_lwp->lwp_md.md_regs;
1572 vkernel_trap(p, tf);
1575 lwp_delsig(lp, sig);
1576 action = ps->ps_sigact[_SIG_IDX(sig)];
1578 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
1579 ktrpsig(p, sig, action, lp->lwp_flag & LWP_OLDMASK ?
1580 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
1582 STOPEVENT(p, S_SIG, sig);
1584 if (action == SIG_DFL) {
1586 * Default action, where the default is to kill
1587 * the process. (Other cases were ignored above.)
1593 * If we get here, the signal must be caught.
1595 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
1596 ("postsig action"));
1601 * Reset the signal handler if asked to
1603 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1605 * See kern_sigaction() for origin of this code.
1607 SIGDELSET(p->p_sigcatch, sig);
1608 if (sig != SIGCONT &&
1609 sigprop(sig) & SA_IGNORE)
1610 SIGADDSET(p->p_sigignore, sig);
1611 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1615 * Handle the mailbox case. Copyout to the appropriate
1616 * location but do not generate a signal frame. The system
1617 * call simply returns EINTR and the user is responsible for
1618 * polling the mailbox.
1620 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) {
1622 copyout(&sig_copy, (void *)action, sizeof(int));
1623 curproc->p_flag |= P_MAILBOX;
1629 * Set the signal mask and calculate the mask to restore
1630 * when the signal function returns.
1632 * Special case: user has done a sigsuspend. Here the
1633 * current mask is not of interest, but rather the
1634 * mask from before the sigsuspend is what we want
1635 * restored after the signal processing is completed.
1637 if (lp->lwp_flag & LWP_OLDMASK) {
1638 returnmask = lp->lwp_oldsigmask;
1639 lp->lwp_flag &= ~LWP_OLDMASK;
1641 returnmask = lp->lwp_sigmask;
1644 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
1645 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1646 SIGADDSET(lp->lwp_sigmask, sig);
1649 lp->lwp_ru.ru_nsignals++;
1650 if (lp->lwp_sig != sig) {
1653 code = lp->lwp_code;
1657 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
1664 * Kill the current process for stated reason.
1667 killproc(struct proc *p, char *why)
1669 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
1670 p->p_pid, p->p_comm,
1671 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1672 ksignal(p, SIGKILL);
1676 * Force the current process to exit with the specified signal, dumping core
1677 * if appropriate. We bypass the normal tests for masked and caught signals,
1678 * allowing unrecoverable failures to terminate the process without changing
1679 * signal state. Mark the accounting record with the signal termination.
1680 * If dumping core, save the signal number for the debugger. Calls exit and
1684 sigexit(struct proc *p, int sig)
1686 struct lwp *lp = FIRST_LWP_IN_PROC(p); /* XXX lwp */
1688 p->p_acflag |= AXSIG;
1689 if (sigprop(sig) & SA_CORE) {
1692 * Log signals which would cause core dumps
1693 * (Log as LOG_INFO to appease those who don't want
1695 * XXX : Todo, as well as euid, write out ruid too
1697 if (coredump(lp, sig) == 0)
1699 if (kern_logsigexit)
1701 "pid %d (%s), uid %d: exited on signal %d%s\n",
1702 p->p_pid, p->p_comm,
1703 p->p_ucred ? p->p_ucred->cr_uid : -1,
1705 sig & WCOREFLAG ? " (core dumped)" : "");
1707 exit1(W_EXITCODE(0, sig));
1711 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
1712 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
1713 sizeof(corefilename), "process corefile name format string");
1716 * expand_name(name, uid, pid)
1717 * Expand the name described in corefilename, using name, uid, and pid.
1718 * corefilename is a kprintf-like string, with three format specifiers:
1719 * %N name of process ("name")
1720 * %P process id (pid)
1722 * For example, "%N.core" is the default; they can be disabled completely
1723 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
1724 * This is controlled by the sysctl variable kern.corefile (see above).
1728 expand_name(const char *name, uid_t uid, pid_t pid)
1731 char buf[11]; /* Buffer for pid/uid -- max 4B */
1733 char *format = corefilename;
1736 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
1739 namelen = strlen(name);
1740 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
1742 switch (format[i]) {
1743 case '%': /* Format character */
1745 switch (format[i]) {
1749 case 'N': /* process name */
1750 if ((n + namelen) > MAXPATHLEN) {
1751 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1752 pid, name, uid, temp, name);
1753 kfree(temp, M_TEMP);
1756 memcpy(temp+n, name, namelen);
1759 case 'P': /* process id */
1760 l = ksprintf(buf, "%u", pid);
1761 if ((n + l) > MAXPATHLEN) {
1762 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1763 pid, name, uid, temp, name);
1764 kfree(temp, M_TEMP);
1767 memcpy(temp+n, buf, l);
1770 case 'U': /* user id */
1771 l = ksprintf(buf, "%u", uid);
1772 if ((n + l) > MAXPATHLEN) {
1773 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1774 pid, name, uid, temp, name);
1775 kfree(temp, M_TEMP);
1778 memcpy(temp+n, buf, l);
1782 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
1786 temp[n++] = format[i];
1794 * Dump a process' core. The main routine does some
1795 * policy checking, and creates the name of the coredump;
1796 * then it passes on a vnode and a size limit to the process-specific
1797 * coredump routine if there is one; if there _is not_ one, it returns
1798 * ENOSYS; otherwise it returns the error from the process-specific routine.
1800 * The parameter `lp' is the lwp which triggered the coredump.
1804 coredump(struct lwp *lp, int sig)
1806 struct proc *p = lp->lwp_proc;
1808 struct ucred *cred = p->p_ucred;
1810 struct nlookupdata nd;
1813 char *name; /* name of corefile */
1816 STOPEVENT(p, S_CORE, 0);
1818 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
1822 * Note that the bulk of limit checking is done after
1823 * the corefile is created. The exception is if the limit
1824 * for corefiles is 0, in which case we don't bother
1825 * creating the corefile at all. This layout means that
1826 * a corefile is truncated instead of not being created,
1827 * if it is larger than the limit.
1829 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
1833 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
1836 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
1838 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
1839 kfree(name, M_TEMP);
1845 nd.nl_open_vp = NULL;
1849 lf.l_whence = SEEK_SET;
1852 lf.l_type = F_WRLCK;
1853 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
1857 /* Don't dump to non-regular files or files with links. */
1858 if (vp->v_type != VREG ||
1859 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
1865 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1867 VOP_SETATTR(vp, &vattr, cred);
1868 p->p_acflag |= ACORE;
1871 error = p->p_sysent->sv_coredump ?
1872 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
1875 lf.l_type = F_UNLCK;
1876 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
1878 error1 = vn_close(vp, FWRITE);
1885 * Nonexistent system call-- signal process (may want to handle it).
1886 * Flag error in case process won't see signal immediately (blocked or ignored).
1890 sys_nosys(struct nosys_args *args)
1892 ksignal(curproc, SIGSYS);
1897 * Send a SIGIO or SIGURG signal to a process or process group using
1898 * stored credentials rather than those of the current process.
1901 pgsigio(struct sigio *sigio, int sig, int checkctty)
1906 if (sigio->sio_pgid > 0) {
1907 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
1909 ksignal(sigio->sio_proc, sig);
1910 } else if (sigio->sio_pgid < 0) {
1913 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE);
1914 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
1915 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
1916 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
1919 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE);
1924 filt_sigattach(struct knote *kn)
1926 struct proc *p = curproc;
1928 kn->kn_ptr.p_proc = p;
1929 kn->kn_flags |= EV_CLEAR; /* automatically set */
1931 /* XXX lock the proc here while adding to the list? */
1932 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
1938 filt_sigdetach(struct knote *kn)
1940 struct proc *p = kn->kn_ptr.p_proc;
1942 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
1946 * signal knotes are shared with proc knotes, so we apply a mask to
1947 * the hint in order to differentiate them from process hints. This
1948 * could be avoided by using a signal-specific knote list, but probably
1949 * isn't worth the trouble.
1952 filt_signal(struct knote *kn, long hint)
1954 if (hint & NOTE_SIGNAL) {
1955 hint &= ~NOTE_SIGNAL;
1957 if (kn->kn_id == hint)
1960 return (kn->kn_data != 0);