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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 1.39 2005/11/14 18:50:05 dillon 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>
60 #include <sys/ktrace.h>
61 #include <sys/syslog.h>
63 #include <sys/sysent.h>
64 #include <sys/sysctl.h>
65 #include <sys/malloc.h>
66 #include <sys/unistd.h>
67 #include <sys/kern_syscall.h>
68 #include <sys/thread2.h>
71 #include <machine/ipl.h>
72 #include <machine/cpu.h>
73 #include <machine/smp.h>
75 static int coredump(struct proc *);
76 static char *expand_name(const char *, uid_t, pid_t);
77 static int killpg(int sig, int pgid, int all);
78 static int sig_ffs(sigset_t *set);
79 static int sigprop(int sig);
81 static void signotify_remote(void *arg);
83 static int kern_sigtimedwait(sigset_t set, siginfo_t *info,
84 struct timespec *timeout);
86 static int filt_sigattach(struct knote *kn);
87 static void filt_sigdetach(struct knote *kn);
88 static int filt_signal(struct knote *kn, long hint);
90 struct filterops sig_filtops =
91 { 0, filt_sigattach, filt_sigdetach, filt_signal };
93 static int kern_logsigexit = 1;
94 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
96 "Log processes quitting on abnormal signals to syslog(3)");
99 * Can process p, with pcred pc, send the signal sig to process q?
101 #define CANSIGNAL(q, sig) \
102 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \
103 ((sig) == SIGCONT && (q)->p_session == curproc->p_session))
106 * Policy -- Can real uid ruid with ucred uc send a signal to process q?
108 #define CANSIGIO(ruid, uc, q) \
109 ((uc)->cr_uid == 0 || \
110 (ruid) == (q)->p_ucred->cr_ruid || \
111 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \
112 (ruid) == (q)->p_ucred->cr_uid || \
113 (uc)->cr_uid == (q)->p_ucred->cr_uid)
116 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
117 &sugid_coredump, 0, "Enable coredumping set user/group ID processes");
119 static int do_coredump = 1;
120 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
121 &do_coredump, 0, "Enable/Disable coredumps");
124 * Signal properties and actions.
125 * The array below categorizes the signals and their default actions
126 * according to the following properties:
128 #define SA_KILL 0x01 /* terminates process by default */
129 #define SA_CORE 0x02 /* ditto and coredumps */
130 #define SA_STOP 0x04 /* suspend process */
131 #define SA_TTYSTOP 0x08 /* ditto, from tty */
132 #define SA_IGNORE 0x10 /* ignore by default */
133 #define SA_CONT 0x20 /* continue if suspended */
134 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
135 #define SA_CKPT 0x80 /* checkpoint process */
138 static int sigproptbl[NSIG] = {
139 SA_KILL, /* SIGHUP */
140 SA_KILL, /* SIGINT */
141 SA_KILL|SA_CORE, /* SIGQUIT */
142 SA_KILL|SA_CORE, /* SIGILL */
143 SA_KILL|SA_CORE, /* SIGTRAP */
144 SA_KILL|SA_CORE, /* SIGABRT */
145 SA_KILL|SA_CORE, /* SIGEMT */
146 SA_KILL|SA_CORE, /* SIGFPE */
147 SA_KILL, /* SIGKILL */
148 SA_KILL|SA_CORE, /* SIGBUS */
149 SA_KILL|SA_CORE, /* SIGSEGV */
150 SA_KILL|SA_CORE, /* SIGSYS */
151 SA_KILL, /* SIGPIPE */
152 SA_KILL, /* SIGALRM */
153 SA_KILL, /* SIGTERM */
154 SA_IGNORE, /* SIGURG */
155 SA_STOP, /* SIGSTOP */
156 SA_STOP|SA_TTYSTOP, /* SIGTSTP */
157 SA_IGNORE|SA_CONT, /* SIGCONT */
158 SA_IGNORE, /* SIGCHLD */
159 SA_STOP|SA_TTYSTOP, /* SIGTTIN */
160 SA_STOP|SA_TTYSTOP, /* SIGTTOU */
161 SA_IGNORE, /* SIGIO */
162 SA_KILL, /* SIGXCPU */
163 SA_KILL, /* SIGXFSZ */
164 SA_KILL, /* SIGVTALRM */
165 SA_KILL, /* SIGPROF */
166 SA_IGNORE, /* SIGWINCH */
167 SA_IGNORE, /* SIGINFO */
168 SA_KILL, /* SIGUSR1 */
169 SA_KILL, /* SIGUSR2 */
170 SA_IGNORE, /* SIGTHR */
171 SA_CKPT, /* SIGCKPT */
172 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */
210 if (sig > 0 && sig < NSIG)
211 return (sigproptbl[_SIG_IDX(sig)]);
216 sig_ffs(sigset_t *set)
220 for (i = 0; i < _SIG_WORDS; i++)
222 return (ffs(set->__bits[i]) + (i * 32));
227 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact)
229 struct thread *td = curthread;
230 struct proc *p = td->td_proc;
231 struct sigacts *ps = p->p_sigacts;
233 if (sig <= 0 || sig > _SIG_MAXSIG)
237 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
238 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
240 if (SIGISMEMBER(ps->ps_sigonstack, sig))
241 oact->sa_flags |= SA_ONSTACK;
242 if (!SIGISMEMBER(ps->ps_sigintr, sig))
243 oact->sa_flags |= SA_RESTART;
244 if (SIGISMEMBER(ps->ps_sigreset, sig))
245 oact->sa_flags |= SA_RESETHAND;
246 if (SIGISMEMBER(ps->ps_signodefer, sig))
247 oact->sa_flags |= SA_NODEFER;
248 if (SIGISMEMBER(ps->ps_siginfo, sig))
249 oact->sa_flags |= SA_SIGINFO;
250 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP)
251 oact->sa_flags |= SA_NOCLDSTOP;
252 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT)
253 oact->sa_flags |= SA_NOCLDWAIT;
256 if ((sig == SIGKILL || sig == SIGSTOP) &&
257 act->sa_handler != SIG_DFL)
261 * Change setting atomically.
265 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
266 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
267 if (act->sa_flags & SA_SIGINFO) {
268 ps->ps_sigact[_SIG_IDX(sig)] =
269 (__sighandler_t *)act->sa_sigaction;
270 SIGADDSET(ps->ps_siginfo, sig);
272 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
273 SIGDELSET(ps->ps_siginfo, sig);
275 if (!(act->sa_flags & SA_RESTART))
276 SIGADDSET(ps->ps_sigintr, sig);
278 SIGDELSET(ps->ps_sigintr, sig);
279 if (act->sa_flags & SA_ONSTACK)
280 SIGADDSET(ps->ps_sigonstack, sig);
282 SIGDELSET(ps->ps_sigonstack, sig);
283 if (act->sa_flags & SA_RESETHAND)
284 SIGADDSET(ps->ps_sigreset, sig);
286 SIGDELSET(ps->ps_sigreset, sig);
287 if (act->sa_flags & SA_NODEFER)
288 SIGADDSET(ps->ps_signodefer, sig);
290 SIGDELSET(ps->ps_signodefer, sig);
291 if (sig == SIGCHLD) {
292 if (act->sa_flags & SA_NOCLDSTOP)
293 p->p_procsig->ps_flag |= PS_NOCLDSTOP;
295 p->p_procsig->ps_flag &= ~PS_NOCLDSTOP;
296 if (act->sa_flags & SA_NOCLDWAIT) {
298 * Paranoia: since SA_NOCLDWAIT is implemented
299 * by reparenting the dying child to PID 1 (and
300 * trust it to reap the zombie), PID 1 itself
301 * is forbidden to set SA_NOCLDWAIT.
304 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
306 p->p_procsig->ps_flag |= PS_NOCLDWAIT;
308 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
312 * Set bit in p_sigignore for signals that are set to SIG_IGN,
313 * and for signals set to SIG_DFL where the default is to
314 * ignore. However, don't put SIGCONT in p_sigignore, as we
315 * have to restart the process.
317 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
318 (sigprop(sig) & SA_IGNORE &&
319 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
320 /* never to be seen again */
321 SIGDELSET(p->p_siglist, sig);
323 /* easier in psignal */
324 SIGADDSET(p->p_sigignore, sig);
325 SIGDELSET(p->p_sigcatch, sig);
327 SIGDELSET(p->p_sigignore, sig);
328 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
329 SIGDELSET(p->p_sigcatch, sig);
331 SIGADDSET(p->p_sigcatch, sig);
340 sigaction(struct sigaction_args *uap)
342 struct sigaction act, oact;
343 struct sigaction *actp, *oactp;
346 actp = (uap->act != NULL) ? &act : NULL;
347 oactp = (uap->oact != NULL) ? &oact : NULL;
349 error = copyin(uap->act, actp, sizeof(act));
353 error = kern_sigaction(uap->sig, actp, oactp);
354 if (oactp && !error) {
355 error = copyout(oactp, uap->oact, sizeof(oact));
361 * Initialize signal state for process 0;
362 * set to ignore signals that are ignored by default.
365 siginit(struct proc *p)
369 for (i = 1; i <= NSIG; i++)
370 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
371 SIGADDSET(p->p_sigignore, i);
375 * Reset signals for an exec of the specified process.
378 execsigs(struct proc *p)
380 struct sigacts *ps = p->p_sigacts;
384 * Reset caught signals. Held signals remain held
385 * through p_sigmask (unless they were caught,
386 * and are now ignored by default).
388 while (SIGNOTEMPTY(p->p_sigcatch)) {
389 sig = sig_ffs(&p->p_sigcatch);
390 SIGDELSET(p->p_sigcatch, sig);
391 if (sigprop(sig) & SA_IGNORE) {
393 SIGADDSET(p->p_sigignore, sig);
394 SIGDELSET(p->p_siglist, sig);
396 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
399 * Reset stack state to the user stack.
400 * Clear set of signals caught on the signal stack.
402 p->p_sigstk.ss_flags = SS_DISABLE;
403 p->p_sigstk.ss_size = 0;
404 p->p_sigstk.ss_sp = 0;
405 p->p_flag &= ~P_ALTSTACK;
407 * Reset no zombies if child dies flag as Solaris does.
409 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
413 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
415 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
419 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
421 struct thread *td = curthread;
422 struct proc *p = td->td_proc;
426 *oset = p->p_sigmask;
433 SIGSETOR(p->p_sigmask, *set);
436 SIGSETNAND(p->p_sigmask, *set);
451 * sigprocmask() - MP SAFE
454 sigprocmask(struct sigprocmask_args *uap)
457 sigset_t *setp, *osetp;
460 setp = (uap->set != NULL) ? &set : NULL;
461 osetp = (uap->oset != NULL) ? &oset : NULL;
463 error = copyin(uap->set, setp, sizeof(set));
467 error = kern_sigprocmask(uap->how, setp, osetp);
468 if (osetp && !error) {
469 error = copyout(osetp, uap->oset, sizeof(oset));
475 kern_sigpending(struct __sigset *set)
477 struct thread *td = curthread;
478 struct proc *p = td->td_proc;
486 sigpending(struct sigpending_args *uap)
491 error = kern_sigpending(&set);
494 error = copyout(&set, uap->set, sizeof(set));
499 * Suspend process until signal, providing mask to be set
503 kern_sigsuspend(struct __sigset *set)
505 struct thread *td = curthread;
506 struct proc *p = td->td_proc;
507 struct sigacts *ps = p->p_sigacts;
510 * When returning from sigsuspend, we want
511 * the old mask to be restored after the
512 * signal handler has finished. Thus, we
513 * save it here and mark the sigacts structure
516 p->p_oldsigmask = p->p_sigmask;
517 p->p_flag |= P_OLDMASK;
521 while (tsleep(ps, PCATCH, "pause", 0) == 0)
523 /* always return EINTR rather than ERESTART... */
528 * Note nonstandard calling convention: libc stub passes mask, not
529 * pointer, to save a copyin.
532 sigsuspend(struct sigsuspend_args *uap)
537 error = copyin(uap->sigmask, &mask, sizeof(mask));
541 error = kern_sigsuspend(&mask);
547 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss)
549 struct thread *td = curthread;
550 struct proc *p = td->td_proc;
552 if ((p->p_flag & P_ALTSTACK) == 0)
553 p->p_sigstk.ss_flags |= SS_DISABLE;
559 if (ss->ss_flags & SS_DISABLE) {
560 if (p->p_sigstk.ss_flags & SS_ONSTACK)
562 p->p_flag &= ~P_ALTSTACK;
563 p->p_sigstk.ss_flags = ss->ss_flags;
565 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
567 p->p_flag |= P_ALTSTACK;
576 sigaltstack(struct sigaltstack_args *uap)
582 error = copyin(uap->ss, &ss, sizeof(ss));
587 error = kern_sigaltstack(uap->ss ? &ss : NULL,
588 uap->oss ? &oss : NULL);
590 if (error == 0 && uap->oss)
591 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
596 * Common code for kill process group/broadcast kill.
597 * cp is calling process.
600 killpg(int sig, int pgid, int all)
602 struct proc *cp = curproc;
611 FOREACH_PROC_IN_SYSTEM(p) {
612 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
613 p == cp || !CANSIGNAL(p, sig))
622 * zero pgid means send to my process group.
630 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
631 if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
632 p->p_stat == SZOMB ||
640 return (nfound ? 0 : ESRCH);
644 kern_kill(int sig, int pid)
646 struct thread *td = curthread;
647 struct proc *p = td->td_proc;
649 if ((u_int)sig > _SIG_MAXSIG)
652 /* kill single process */
653 if ((p = pfind(pid)) == NULL)
655 if (!CANSIGNAL(p, sig))
662 case -1: /* broadcast signal */
663 return (killpg(sig, 0, 1));
664 case 0: /* signal own process group */
665 return (killpg(sig, 0, 0));
666 default: /* negative explicit process group */
667 return (killpg(sig, -pid, 0));
673 kill(struct kill_args *uap)
677 error = kern_kill(uap->signum, uap->pid);
683 * Send a signal to a process group.
686 gsignal(int pgid, int sig)
690 if (pgid && (pgrp = pgfind(pgid)))
691 pgsignal(pgrp, sig, 0);
695 * Send a signal to a process group. If checktty is 1,
696 * limit to members which have a controlling terminal.
699 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
704 LIST_FOREACH(p, &pgrp->pg_members, p_pglist)
705 if (checkctty == 0 || p->p_flag & P_CONTROLT)
710 * Send a signal caused by a trap to the current process.
711 * If it will be caught immediately, deliver it with correct code.
712 * Otherwise, post it normally.
715 trapsignal(struct proc *p, int sig, u_long code)
717 struct sigacts *ps = p->p_sigacts;
719 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
720 !SIGISMEMBER(p->p_sigmask, sig)) {
721 p->p_stats->p_ru.ru_nsignals++;
723 if (KTRPOINT(p->p_thread, KTR_PSIG))
724 ktrpsig(p->p_tracep, sig, ps->ps_sigact[_SIG_IDX(sig)],
725 &p->p_sigmask, code);
727 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
728 &p->p_sigmask, code);
729 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
730 if (!SIGISMEMBER(ps->ps_signodefer, sig))
731 SIGADDSET(p->p_sigmask, sig);
732 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
734 * See kern_sigaction() for origin of this code.
736 SIGDELSET(p->p_sigcatch, sig);
737 if (sig != SIGCONT &&
738 sigprop(sig) & SA_IGNORE)
739 SIGADDSET(p->p_sigignore, sig);
740 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
743 p->p_code = code; /* XXX for core dump/debugger */
744 p->p_sig = sig; /* XXX to verify code */
750 * Send the signal to the process. If the signal has an action, the action
751 * is usually performed by the target process rather than the caller; we add
752 * the signal to the set of pending signals for the process.
755 * o When a stop signal is sent to a sleeping process that takes the
756 * default action, the process is stopped without awakening it.
757 * o SIGCONT restarts stopped processes (or puts them back to sleep)
758 * regardless of the signal action (eg, blocked or ignored).
760 * Other ignored signals are discarded immediately.
763 psignal(struct proc *p, int sig)
765 struct lwp *lp = &p->p_lwp;
769 if (sig > _SIG_MAXSIG || sig <= 0) {
770 printf("psignal: signal %d\n", sig);
771 panic("psignal signal number");
775 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
781 * If proc is traced, always give parent a chance;
782 * if signal event is tracked by procfs, give *that*
785 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
789 * If the signal is being ignored,
790 * then we forget about it immediately.
791 * (Note: we don't set SIGCONT in p_sigignore,
792 * and if it is set to SIG_IGN,
793 * action will be SIG_DFL here.)
795 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT))
797 if (SIGISMEMBER(p->p_sigmask, sig))
799 else if (SIGISMEMBER(p->p_sigcatch, sig))
805 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
806 (p->p_flag & P_TRACED) == 0) {
811 * If continuing, clear any pending STOP signals.
814 SIG_STOPSIGMASK(p->p_siglist);
816 if (prop & SA_STOP) {
818 * If sending a tty stop signal to a member of an orphaned
819 * process group, discard the signal here if the action
820 * is default; don't stop the process below if sleeping,
821 * and don't clear any pending SIGCONT.
823 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
827 SIG_CONTSIGMASK(p->p_siglist);
829 SIGADDSET(p->p_siglist, sig);
832 * Defer further processing for signals which are held,
833 * except that stopped processes must be continued by SIGCONT.
835 if (action == SIG_HOLD) {
836 if ((prop & SA_CONT) == 0 || (p->p_flag & P_STOPPED) == 0)
843 * Process is in tsleep and not stopped
845 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED) == 0) {
847 * If the process is sleeping uninterruptibly
848 * we can't interrupt the sleep... the signal will
849 * be noticed when the process returns through
850 * trap() or syscall().
852 if ((p->p_flag & P_SINTR) == 0)
856 * If the process is sleeping and traced, make it runnable
857 * so it can discover the signal in issignal() and stop
860 * If the process is stopped and traced, no further action
863 if (p->p_flag & P_TRACED)
867 * If the process is sleeping and SA_CONT, and the signal
868 * mode is SIG_DFL, then make the process runnable.
870 * However, do *NOT* set P_BREAKTSLEEP. We do not want
871 * a SIGCONT to terminate an interruptable tsleep early
872 * and generate a spurious EINTR.
874 if ((prop & SA_CONT) && action == SIG_DFL) {
875 SIGDELSET(p->p_siglist, sig);
880 * If the process is sleeping and receives a STOP signal,
881 * process immediately if possible. All other (caught or
882 * default) signals cause the process to run.
884 if (prop & SA_STOP) {
885 if (action != SIG_DFL)
889 * If a child holding parent blocked, stopping
890 * could cause deadlock. Take no action at this
893 if (p->p_flag & P_PPWAIT)
897 * Do not actually try to manipulate the process
898 * while it is sleeping, simply set P_STOPPED to
899 * indicate that it should stop as soon as it safely
902 SIGDELSET(p->p_siglist, sig);
903 p->p_flag |= P_STOPPED;
904 p->p_flag &= ~P_WAITED;
906 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0)
907 psignal(p->p_pptr, SIGCHLD);
912 * Otherwise the signal can interrupt the sleep.
918 * Process is in tsleep and is stopped
920 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED)) {
922 * If the process is stopped and is being traced, then no
923 * further action is necessary.
925 if (p->p_flag & P_TRACED)
929 * If the process is stopped and receives a KILL signal,
930 * make the process runnable.
936 * If the process is stopped and receives a CONT signal,
937 * then try to make the process runnable again.
939 if (prop & SA_CONT) {
941 * If SIGCONT is default (or ignored), we continue the
942 * process but don't leave the signal in p_siglist, as
943 * it has no further action. If SIGCONT is held, we
944 * continue the process and leave the signal in
945 * p_siglist. If the process catches SIGCONT, let it
946 * handle the signal itself.
948 if (action == SIG_DFL)
949 SIGDELSET(p->p_siglist, sig);
950 if (action == SIG_CATCH)
954 * Make runnable but do not break a tsleep unless
955 * some other signal was pending.
961 * If the process is stopped and receives another STOP
962 * signal, we do not need to stop it again. If we did
963 * the shell could get confused.
965 if (prop & SA_STOP) {
966 SIGDELSET(p->p_siglist, sig);
971 * Otherwise the process is sleeping interruptably but
972 * is stopped, just set the P_BREAKTSLEEP flag and take
973 * no further action. The next runnable action will wake
976 p->p_flag |= P_BREAKTSLEEP;
981 * Otherwise the process is running
983 * SRUN, SIDL, SZOMB do nothing with the signal,
984 * other than kicking ourselves if we are running.
985 * It will either never be noticed, or noticed very soon.
987 * Note that p_thread may be NULL or may not be completely
988 * initialized if the process is in the SIDL or SZOMB state.
990 * For SMP we may have to forward the request to another cpu.
991 * YYY the MP lock prevents the target process from moving
992 * to another cpu, see kern/kern_switch.c
994 * If the target thread is waiting on its message port,
995 * wakeup the target thread so it can check (or ignore)
996 * the new signal. YYY needs cleanup.
998 if (lp == lwkt_preempted_proc()) {
1000 } else if (p->p_stat == SRUN) {
1001 struct thread *td = p->p_thread;
1004 ("pid %d NULL p_thread stat %d flags %08x",
1005 p->p_pid, p->p_stat, p->p_flag));
1008 if (td->td_gd != mycpu)
1009 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1012 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1019 * Make runnable and break out of any tsleep as well.
1021 p->p_flag |= P_BREAKTSLEEP;
1031 * This function is called via an IPI. We will be in a critical section but
1032 * the MP lock will NOT be held. Also note that by the time the ipi message
1033 * gets to us the process 'p' (arg) may no longer be scheduled or even valid.
1036 signotify_remote(void *arg)
1038 struct lwp *lp = arg;
1040 if (lp == lwkt_preempted_proc()) {
1043 struct thread *td = lp->lwp_thread;
1044 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1052 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1054 sigset_t savedmask, set;
1055 struct proc *p = curproc;
1056 int error, sig, hz, timevalid = 0;
1057 struct timespec rts, ets, ts;
1062 SIG_CANTMASK(waitset);
1063 savedmask = p->p_sigmask;
1066 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1067 timeout->tv_nsec < 1000000000) {
1069 getnanouptime(&rts);
1071 timespecadd(&ets, timeout);
1077 SIGSETAND(set, waitset);
1078 if ((sig = sig_ffs(&set)) != 0) {
1079 SIGFILLSET(p->p_sigmask);
1080 SIGDELSET(p->p_sigmask, sig);
1081 SIG_CANTMASK(p->p_sigmask);
1084 * It may be a STOP signal, in the case, issignal
1085 * returns 0, because we may stop there, and new
1086 * signal can come in, we should restart if we got
1096 * Previous checking got nothing, and we retried but still
1097 * got nothing, we should return the error status.
1103 * POSIX says this must be checked after looking for pending
1111 getnanouptime(&rts);
1112 if (timespeccmp(&rts, &ets, >=)) {
1117 timespecsub(&ts, &rts);
1118 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1119 hz = tvtohz_high(&tv);
1123 p->p_sigmask = savedmask;
1124 SIGSETNAND(p->p_sigmask, waitset);
1125 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1127 if (error == ERESTART) {
1128 /* can not restart a timeout wait. */
1130 } else if (error == EAGAIN) {
1131 /* will calculate timeout by ourself. */
1138 p->p_sigmask = savedmask;
1141 bzero(info, sizeof(*info));
1142 info->si_signo = sig;
1143 SIGDELSET(p->p_siglist, sig); /* take the signal! */
1149 sigtimedwait(struct sigtimedwait_args *uap)
1152 struct timespec *timeout;
1158 error = copyin(uap->timeout, &ts, sizeof(ts));
1165 error = copyin(uap->set, &set, sizeof(set));
1168 error = kern_sigtimedwait(set, &info, timeout);
1172 error = copyout(&info, uap->info, sizeof(info));
1173 /* Repost if we got an error. */
1175 psignal(curproc, info.si_signo);
1177 uap->sysmsg_result = info.si_signo;
1182 sigwaitinfo(struct sigwaitinfo_args *uap)
1188 error = copyin(uap->set, &set, sizeof(set));
1191 error = kern_sigtimedwait(set, &info, NULL);
1195 error = copyout(&info, uap->info, sizeof(info));
1196 /* Repost if we got an error. */
1198 psignal(curproc, info.si_signo);
1200 uap->sysmsg_result = info.si_signo;
1205 * If the current process has received a signal that would interrupt a
1206 * system call, return EINTR or ERESTART as appropriate.
1209 iscaught(struct proc *p)
1214 if ((sig = CURSIG(p)) != 0) {
1215 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1220 return(EWOULDBLOCK);
1224 * If the current process has received a signal (should be caught or cause
1225 * termination, should interrupt current syscall), return the signal number.
1226 * Stop signals with default action are processed immediately, then cleared;
1227 * they aren't returned. This is checked after each entry to the system for
1228 * a syscall or trap (though this can usually be done without calling issignal
1229 * by checking the pending signal masks in the CURSIG macro.) The normal call
1232 * while (sig = CURSIG(curproc))
1236 issignal(struct proc *p)
1242 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1244 mask = p->p_siglist;
1245 SIGSETNAND(mask, p->p_sigmask);
1246 if (p->p_flag & P_PPWAIT)
1247 SIG_STOPSIGMASK(mask);
1248 if (!SIGNOTEMPTY(mask)) /* no signal to send */
1250 sig = sig_ffs(&mask);
1252 STOPEVENT(p, S_SIG, sig);
1255 * We should see pending but ignored signals
1256 * only if P_TRACED was on when they were posted.
1258 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1259 SIGDELSET(p->p_siglist, sig);
1262 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1264 * If traced, always stop, and stay stopped until
1265 * released by the parent.
1267 * NOTE: P_STOPPED may get cleared during the loop,
1268 * but we do not re-notify the parent if we have
1269 * to loop several times waiting for the parent
1270 * to let us continue.
1273 p->p_flag |= P_STOPPED;
1274 p->p_flag &= ~P_WAITED;
1275 psignal(p->p_pptr, SIGCHLD);
1278 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1279 p->p_flag &= ~P_STOPPED;
1282 * If parent wants us to take the signal,
1283 * then it will leave it in p->p_xstat;
1284 * otherwise we just look for signals again.
1286 SIGDELSET(p->p_siglist, sig); /* clear old signal */
1292 * Put the new signal into p_siglist. If the
1293 * signal is being masked, look for other signals.
1295 SIGADDSET(p->p_siglist, sig);
1296 if (SIGISMEMBER(p->p_sigmask, sig))
1300 * If the traced bit got turned off, go back up
1301 * to the top to rescan signals. This ensures
1302 * that p_sig* and ps_sigact are consistent.
1304 if ((p->p_flag & P_TRACED) == 0)
1308 prop = sigprop(sig);
1311 * Decide whether the signal should be returned.
1312 * Return the signal's number, or fall through
1313 * to clear it from the pending mask.
1315 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1318 * Don't take default actions on system processes.
1320 if (p->p_pid <= 1) {
1323 * Are you sure you want to ignore SIGSEGV
1326 printf("Process (pid %lu) got signal %d\n",
1327 (u_long)p->p_pid, sig);
1329 break; /* == ignore */
1333 * Handle the in-kernel checkpoint action
1335 if (prop & SA_CKPT) {
1336 checkpoint_signal_handler(p);
1341 * If there is a pending stop signal to process
1342 * with default action, stop here,
1343 * then clear the signal. However,
1344 * if process is member of an orphaned
1345 * process group, ignore tty stop signals.
1347 if (prop & SA_STOP) {
1348 if (p->p_flag & P_TRACED ||
1349 (p->p_pgrp->pg_jobc == 0 &&
1351 break; /* == ignore */
1353 p->p_flag |= P_STOPPED;
1354 p->p_flag &= ~P_WAITED;
1356 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0)
1357 psignal(p->p_pptr, SIGCHLD);
1358 while (p->p_flag & P_STOPPED) {
1362 } else if (prop & SA_IGNORE) {
1364 * Except for SIGCONT, shouldn't get here.
1365 * Default action is to ignore; drop it.
1367 break; /* == ignore */
1376 * Masking above should prevent us ever trying
1377 * to take action on an ignored signal other
1378 * than SIGCONT, unless process is traced.
1380 if ((prop & SA_CONT) == 0 &&
1381 (p->p_flag & P_TRACED) == 0)
1382 printf("issignal\n");
1383 break; /* == ignore */
1387 * This signal has an action, let
1388 * postsig() process it.
1392 SIGDELSET(p->p_siglist, sig); /* take the signal! */
1398 * Take the action for the specified signal
1399 * from the current set of pending signals.
1404 struct proc *p = curproc;
1405 struct sigacts *ps = p->p_sigacts;
1407 sigset_t returnmask;
1410 KASSERT(sig != 0, ("postsig"));
1412 SIGDELSET(p->p_siglist, sig);
1413 action = ps->ps_sigact[_SIG_IDX(sig)];
1415 if (KTRPOINT(p->p_thread, KTR_PSIG))
1416 ktrpsig(p->p_tracep, sig, action, p->p_flag & P_OLDMASK ?
1417 &p->p_oldsigmask : &p->p_sigmask, 0);
1419 STOPEVENT(p, S_SIG, sig);
1421 if (action == SIG_DFL) {
1423 * Default action, where the default is to kill
1424 * the process. (Other cases were ignored above.)
1430 * If we get here, the signal must be caught.
1432 KASSERT(action != SIG_IGN && !SIGISMEMBER(p->p_sigmask, sig),
1433 ("postsig action"));
1435 * Set the new mask value and also defer further
1436 * occurrences of this signal.
1438 * Special case: user has done a sigsuspend. Here the
1439 * current mask is not of interest, but rather the
1440 * mask from before the sigsuspend is what we want
1441 * restored after the signal processing is completed.
1444 if (p->p_flag & P_OLDMASK) {
1445 returnmask = p->p_oldsigmask;
1446 p->p_flag &= ~P_OLDMASK;
1448 returnmask = p->p_sigmask;
1451 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
1452 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1453 SIGADDSET(p->p_sigmask, sig);
1455 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1457 * See kern_sigaction() for origin of this code.
1459 SIGDELSET(p->p_sigcatch, sig);
1460 if (sig != SIGCONT &&
1461 sigprop(sig) & SA_IGNORE)
1462 SIGADDSET(p->p_sigignore, sig);
1463 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1466 p->p_stats->p_ru.ru_nsignals++;
1467 if (p->p_sig != sig) {
1474 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
1479 * Kill the current process for stated reason.
1482 killproc(struct proc *p, char *why)
1484 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm,
1485 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1486 psignal(p, SIGKILL);
1490 * Force the current process to exit with the specified signal, dumping core
1491 * if appropriate. We bypass the normal tests for masked and caught signals,
1492 * allowing unrecoverable failures to terminate the process without changing
1493 * signal state. Mark the accounting record with the signal termination.
1494 * If dumping core, save the signal number for the debugger. Calls exit and
1498 sigexit(struct proc *p, int sig)
1500 p->p_acflag |= AXSIG;
1501 if (sigprop(sig) & SA_CORE) {
1504 * Log signals which would cause core dumps
1505 * (Log as LOG_INFO to appease those who don't want
1507 * XXX : Todo, as well as euid, write out ruid too
1509 if (coredump(p) == 0)
1511 if (kern_logsigexit)
1513 "pid %d (%s), uid %d: exited on signal %d%s\n",
1514 p->p_pid, p->p_comm,
1515 p->p_ucred ? p->p_ucred->cr_uid : -1,
1517 sig & WCOREFLAG ? " (core dumped)" : "");
1519 exit1(W_EXITCODE(0, sig));
1523 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
1524 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
1525 sizeof(corefilename), "process corefile name format string");
1528 * expand_name(name, uid, pid)
1529 * Expand the name described in corefilename, using name, uid, and pid.
1530 * corefilename is a printf-like string, with three format specifiers:
1531 * %N name of process ("name")
1532 * %P process id (pid)
1534 * For example, "%N.core" is the default; they can be disabled completely
1535 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
1536 * This is controlled by the sysctl variable kern.corefile (see above).
1540 expand_name(const char *name, uid_t uid, pid_t pid)
1543 char buf[11]; /* Buffer for pid/uid -- max 4B */
1545 char *format = corefilename;
1548 temp = malloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
1551 namelen = strlen(name);
1552 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
1554 switch (format[i]) {
1555 case '%': /* Format character */
1557 switch (format[i]) {
1561 case 'N': /* process name */
1562 if ((n + namelen) > MAXPATHLEN) {
1563 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1564 pid, name, uid, temp, name);
1568 memcpy(temp+n, name, namelen);
1571 case 'P': /* process id */
1572 l = sprintf(buf, "%u", pid);
1573 if ((n + l) > MAXPATHLEN) {
1574 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1575 pid, name, uid, temp, name);
1579 memcpy(temp+n, buf, l);
1582 case 'U': /* user id */
1583 l = sprintf(buf, "%u", uid);
1584 if ((n + l) > MAXPATHLEN) {
1585 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1586 pid, name, uid, temp, name);
1590 memcpy(temp+n, buf, l);
1594 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
1598 temp[n++] = format[i];
1606 * Dump a process' core. The main routine does some
1607 * policy checking, and creates the name of the coredump;
1608 * then it passes on a vnode and a size limit to the process-specific
1609 * coredump routine if there is one; if there _is not_ one, it returns
1610 * ENOSYS; otherwise it returns the error from the process-specific routine.
1614 coredump(struct proc *p)
1617 struct ucred *cred = p->p_ucred;
1618 struct thread *td = p->p_thread;
1620 struct nlookupdata nd;
1623 char *name; /* name of corefile */
1626 STOPEVENT(p, S_CORE, 0);
1628 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
1632 * Note that the bulk of limit checking is done after
1633 * the corefile is created. The exception is if the limit
1634 * for corefiles is 0, in which case we don't bother
1635 * creating the corefile at all. This layout means that
1636 * a corefile is truncated instead of not being created,
1637 * if it is larger than the limit.
1639 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
1643 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
1646 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
1648 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
1655 nd.nl_open_vp = NULL;
1658 VOP_UNLOCK(vp, 0, td);
1659 lf.l_whence = SEEK_SET;
1662 lf.l_type = F_WRLCK;
1663 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK);
1667 /* Don't dump to non-regular files or files with links. */
1668 if (vp->v_type != VREG ||
1669 VOP_GETATTR(vp, &vattr, td) || vattr.va_nlink != 1) {
1675 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
1677 VOP_LEASE(vp, td, cred, LEASE_WRITE);
1678 VOP_SETATTR(vp, &vattr, cred, td);
1679 p->p_acflag |= ACORE;
1680 VOP_UNLOCK(vp, 0, td);
1682 error = p->p_sysent->sv_coredump ?
1683 p->p_sysent->sv_coredump(p, vp, limit) : ENOSYS;
1686 lf.l_type = F_UNLCK;
1687 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
1689 error1 = vn_close(vp, FWRITE, td);
1696 * Nonexistent system call-- signal process (may want to handle it).
1697 * Flag error in case process won't see signal immediately (blocked or ignored).
1701 nosys(struct nosys_args *args)
1703 psignal(curproc, SIGSYS);
1708 * Send a SIGIO or SIGURG signal to a process or process group using
1709 * stored credentials rather than those of the current process.
1712 pgsigio(struct sigio *sigio, int sig, int checkctty)
1717 if (sigio->sio_pgid > 0) {
1718 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
1720 psignal(sigio->sio_proc, sig);
1721 } else if (sigio->sio_pgid < 0) {
1724 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist)
1725 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
1726 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
1732 filt_sigattach(struct knote *kn)
1734 struct proc *p = curproc;
1736 kn->kn_ptr.p_proc = p;
1737 kn->kn_flags |= EV_CLEAR; /* automatically set */
1739 /* XXX lock the proc here while adding to the list? */
1740 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
1746 filt_sigdetach(struct knote *kn)
1748 struct proc *p = kn->kn_ptr.p_proc;
1750 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
1754 * signal knotes are shared with proc knotes, so we apply a mask to
1755 * the hint in order to differentiate them from process hints. This
1756 * could be avoided by using a signal-specific knote list, but probably
1757 * isn't worth the trouble.
1760 filt_signal(struct knote *kn, long hint)
1762 if (hint & NOTE_SIGNAL) {
1763 hint &= ~NOTE_SIGNAL;
1765 if (kn->kn_id == hint)
1768 return (kn->kn_data != 0);