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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 1.50 2006/06/05 07:26:10 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 sys_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 sys_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 sys_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 sys_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 sys_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.
604 static int killpg_all_callback(struct proc *p, void *data);
607 killpg(int sig, int pgid, int all)
609 struct killpg_info info;
610 struct proc *cp = curproc;
621 allproc_scan(killpg_all_callback, &info);
625 * zero pgid means send to my process group.
633 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
635 (p->p_flag & (P_SYSTEM | P_ZOMBIE)) ||
636 !CANSIGNAL(p, sig)) {
644 return (info.nfound ? 0 : ESRCH);
648 killpg_all_callback(struct proc *p, void *data)
650 struct killpg_info *info = data;
652 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) ||
653 p == curproc || !CANSIGNAL(p, info->sig)) {
658 psignal(p, info->sig);
663 kern_kill(int sig, int pid)
665 struct thread *td = curthread;
666 struct proc *p = td->td_proc;
668 if ((u_int)sig > _SIG_MAXSIG)
671 /* kill single process */
672 if ((p = pfind(pid)) == NULL)
674 if (!CANSIGNAL(p, sig))
681 case -1: /* broadcast signal */
682 return (killpg(sig, 0, 1));
683 case 0: /* signal own process group */
684 return (killpg(sig, 0, 0));
685 default: /* negative explicit process group */
686 return (killpg(sig, -pid, 0));
692 sys_kill(struct kill_args *uap)
696 error = kern_kill(uap->signum, uap->pid);
702 * Send a signal to a process group.
705 gsignal(int pgid, int sig)
709 if (pgid && (pgrp = pgfind(pgid)))
710 pgsignal(pgrp, sig, 0);
714 * Send a signal to a process group. If checktty is 1,
715 * limit to members which have a controlling terminal.
718 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
723 LIST_FOREACH(p, &pgrp->pg_members, p_pglist)
724 if (checkctty == 0 || p->p_flag & P_CONTROLT)
729 * Send a signal caused by a trap to the current process.
730 * If it will be caught immediately, deliver it with correct code.
731 * Otherwise, post it normally.
734 trapsignal(struct proc *p, int sig, u_long code)
736 struct sigacts *ps = p->p_sigacts;
738 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
739 !SIGISMEMBER(p->p_sigmask, sig)) {
740 p->p_stats->p_ru.ru_nsignals++;
742 if (KTRPOINT(p->p_thread, KTR_PSIG))
743 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)],
744 &p->p_sigmask, code);
746 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
747 &p->p_sigmask, code);
748 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
749 if (!SIGISMEMBER(ps->ps_signodefer, sig))
750 SIGADDSET(p->p_sigmask, sig);
751 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
753 * See kern_sigaction() for origin of this code.
755 SIGDELSET(p->p_sigcatch, sig);
756 if (sig != SIGCONT &&
757 sigprop(sig) & SA_IGNORE)
758 SIGADDSET(p->p_sigignore, sig);
759 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
762 p->p_code = code; /* XXX for core dump/debugger */
763 p->p_sig = sig; /* XXX to verify code */
769 * Send the signal to the process. If the signal has an action, the action
770 * is usually performed by the target process rather than the caller; we add
771 * the signal to the set of pending signals for the process.
774 * o When a stop signal is sent to a sleeping process that takes the
775 * default action, the process is stopped without awakening it.
776 * o SIGCONT restarts stopped processes (or puts them back to sleep)
777 * regardless of the signal action (eg, blocked or ignored).
779 * Other ignored signals are discarded immediately.
782 psignal(struct proc *p, int sig)
784 struct lwp *lp = &p->p_lwp;
788 if (sig > _SIG_MAXSIG || sig <= 0) {
789 printf("psignal: signal %d\n", sig);
790 panic("psignal signal number");
794 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
800 * If proc is traced, always give parent a chance;
801 * if signal event is tracked by procfs, give *that*
804 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
808 * If the signal is being ignored,
809 * then we forget about it immediately.
810 * (Note: we don't set SIGCONT in p_sigignore,
811 * and if it is set to SIG_IGN,
812 * action will be SIG_DFL here.)
814 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT))
816 if (SIGISMEMBER(p->p_sigmask, sig))
818 else if (SIGISMEMBER(p->p_sigcatch, sig))
824 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
825 (p->p_flag & P_TRACED) == 0) {
830 * If continuing, clear any pending STOP signals.
833 SIG_STOPSIGMASK(p->p_siglist);
835 if (prop & SA_STOP) {
837 * If sending a tty stop signal to a member of an orphaned
838 * process group, discard the signal here if the action
839 * is default; don't stop the process below if sleeping,
840 * and don't clear any pending SIGCONT.
842 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
846 SIG_CONTSIGMASK(p->p_siglist);
848 SIGADDSET(p->p_siglist, sig);
851 * Defer further processing for signals which are held,
852 * except that stopped processes must be continued by SIGCONT.
854 if (action == SIG_HOLD) {
855 if ((prop & SA_CONT) == 0 || (p->p_flag & P_STOPPED) == 0)
862 * Process is in tsleep and not stopped
864 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED) == 0) {
866 * If the process is sleeping uninterruptibly
867 * we can't interrupt the sleep... the signal will
868 * be noticed when the process returns through
869 * trap() or syscall().
871 if ((p->p_flag & P_SINTR) == 0)
875 * If the process is sleeping and traced, make it runnable
876 * so it can discover the signal in issignal() and stop
879 * If the process is stopped and traced, no further action
882 if (p->p_flag & P_TRACED)
886 * If the process is sleeping and SA_CONT, and the signal
887 * mode is SIG_DFL, then make the process runnable.
889 * However, do *NOT* set P_BREAKTSLEEP. We do not want
890 * a SIGCONT to terminate an interruptable tsleep early
891 * and generate a spurious EINTR.
893 if ((prop & SA_CONT) && action == SIG_DFL) {
894 SIGDELSET(p->p_siglist, sig);
899 * If the process is sleeping and receives a STOP signal,
900 * process immediately if possible. All other (caught or
901 * default) signals cause the process to run.
903 if (prop & SA_STOP) {
904 if (action != SIG_DFL)
908 * If a child holding parent blocked, stopping
909 * could cause deadlock. Take no action at this
912 if (p->p_flag & P_PPWAIT)
916 * Do not actually try to manipulate the process
917 * while it is sleeping, simply set P_STOPPED to
918 * indicate that it should stop as soon as it safely
921 SIGDELSET(p->p_siglist, sig);
922 p->p_flag |= P_STOPPED;
923 p->p_flag &= ~P_WAITED;
926 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0)
927 psignal(p->p_pptr, SIGCHLD);
932 * Otherwise the signal can interrupt the sleep.
938 * Process is in tsleep and is stopped
940 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED)) {
942 * If the process is stopped and is being traced, then no
943 * further action is necessary.
945 if (p->p_flag & P_TRACED)
949 * If the process is stopped and receives a KILL signal,
950 * make the process runnable.
956 * If the process is stopped and receives a CONT signal,
957 * then try to make the process runnable again.
959 if (prop & SA_CONT) {
961 * If SIGCONT is default (or ignored), we continue the
962 * process but don't leave the signal in p_siglist, as
963 * it has no further action. If SIGCONT is held, we
964 * continue the process and leave the signal in
965 * p_siglist. If the process catches SIGCONT, let it
966 * handle the signal itself.
968 if (action == SIG_DFL)
969 SIGDELSET(p->p_siglist, sig);
970 if (action == SIG_CATCH)
974 * Make runnable but do not break a tsleep unless
975 * some other signal was pending.
981 * If the process is stopped and receives another STOP
982 * signal, we do not need to stop it again. If we did
983 * the shell could get confused.
985 if (prop & SA_STOP) {
986 SIGDELSET(p->p_siglist, sig);
991 * Otherwise the process is sleeping interruptably but
992 * is stopped, just set the P_BREAKTSLEEP flag and take
993 * no further action. The next runnable action will wake
996 p->p_flag |= P_BREAKTSLEEP;
1001 * Otherwise the process is running
1003 * SRUN, SIDL, SZOMB do nothing with the signal,
1004 * other than kicking ourselves if we are running.
1005 * It will either never be noticed, or noticed very soon.
1007 * Note that p_thread may be NULL or may not be completely
1008 * initialized if the process is in the SIDL or SZOMB state.
1010 * For SMP we may have to forward the request to another cpu.
1011 * YYY the MP lock prevents the target process from moving
1012 * to another cpu, see kern/kern_switch.c
1014 * If the target thread is waiting on its message port,
1015 * wakeup the target thread so it can check (or ignore)
1016 * the new signal. YYY needs cleanup.
1018 if (lp == lwkt_preempted_proc()) {
1020 } else if (p->p_stat == SRUN) {
1021 struct thread *td = p->p_thread;
1024 ("pid %d NULL p_thread stat %d flags %08x",
1025 p->p_pid, p->p_stat, p->p_flag));
1028 if (td->td_gd != mycpu)
1029 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1032 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1039 * Make runnable and break out of any tsleep as well.
1041 p->p_flag |= P_BREAKTSLEEP;
1051 * This function is called via an IPI. We will be in a critical section but
1052 * the MP lock will NOT be held. Also note that by the time the ipi message
1053 * gets to us the process 'p' (arg) may no longer be scheduled or even valid.
1056 signotify_remote(void *arg)
1058 struct lwp *lp = arg;
1060 if (lp == lwkt_preempted_proc()) {
1063 struct thread *td = lp->lwp_thread;
1064 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1072 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1074 sigset_t savedmask, set;
1075 struct proc *p = curproc;
1076 int error, sig, hz, timevalid = 0;
1077 struct timespec rts, ets, ts;
1082 SIG_CANTMASK(waitset);
1083 savedmask = p->p_sigmask;
1086 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1087 timeout->tv_nsec < 1000000000) {
1089 getnanouptime(&rts);
1091 timespecadd(&ets, timeout);
1097 SIGSETAND(set, waitset);
1098 if ((sig = sig_ffs(&set)) != 0) {
1099 SIGFILLSET(p->p_sigmask);
1100 SIGDELSET(p->p_sigmask, sig);
1101 SIG_CANTMASK(p->p_sigmask);
1104 * It may be a STOP signal, in the case, issignal
1105 * returns 0, because we may stop there, and new
1106 * signal can come in, we should restart if we got
1116 * Previous checking got nothing, and we retried but still
1117 * got nothing, we should return the error status.
1123 * POSIX says this must be checked after looking for pending
1131 getnanouptime(&rts);
1132 if (timespeccmp(&rts, &ets, >=)) {
1137 timespecsub(&ts, &rts);
1138 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1139 hz = tvtohz_high(&tv);
1143 p->p_sigmask = savedmask;
1144 SIGSETNAND(p->p_sigmask, waitset);
1145 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1147 if (error == ERESTART) {
1148 /* can not restart a timeout wait. */
1150 } else if (error == EAGAIN) {
1151 /* will calculate timeout by ourself. */
1158 p->p_sigmask = savedmask;
1161 bzero(info, sizeof(*info));
1162 info->si_signo = sig;
1163 SIGDELSET(p->p_siglist, sig); /* take the signal! */
1172 sys_sigtimedwait(struct sigtimedwait_args *uap)
1175 struct timespec *timeout;
1181 error = copyin(uap->timeout, &ts, sizeof(ts));
1188 error = copyin(uap->set, &set, sizeof(set));
1191 error = kern_sigtimedwait(set, &info, timeout);
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 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1211 error = copyin(uap->set, &set, sizeof(set));
1214 error = kern_sigtimedwait(set, &info, NULL);
1218 error = copyout(&info, uap->info, sizeof(info));
1219 /* Repost if we got an error. */
1221 psignal(curproc, info.si_signo);
1223 uap->sysmsg_result = info.si_signo;
1228 * If the current process has received a signal that would interrupt a
1229 * system call, return EINTR or ERESTART as appropriate.
1232 iscaught(struct proc *p)
1237 if ((sig = CURSIG(p)) != 0) {
1238 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1243 return(EWOULDBLOCK);
1247 * If the current process has received a signal (should be caught or cause
1248 * termination, should interrupt current syscall), return the signal number.
1249 * Stop signals with default action are processed immediately, then cleared;
1250 * they aren't returned. This is checked after each entry to the system for
1251 * a syscall or trap (though this can usually be done without calling issignal
1252 * by checking the pending signal masks in the CURSIG macro.) The normal call
1255 * This routine is called via CURSIG/__cursig and the MP lock might not be
1256 * held. Obtain the MP lock for the duration of the operation.
1258 * while (sig = CURSIG(curproc))
1262 issignal(struct proc *p)
1269 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1271 mask = p->p_siglist;
1272 SIGSETNAND(mask, p->p_sigmask);
1273 if (p->p_flag & P_PPWAIT)
1274 SIG_STOPSIGMASK(mask);
1275 if (!SIGNOTEMPTY(mask)) { /* no signal to send */
1279 sig = sig_ffs(&mask);
1281 STOPEVENT(p, S_SIG, sig);
1284 * We should see pending but ignored signals
1285 * only if P_TRACED was on when they were posted.
1287 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1288 SIGDELSET(p->p_siglist, sig);
1291 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1293 * If traced, always stop, and stay stopped until
1294 * released by the parent.
1296 * NOTE: P_STOPPED may get cleared during the loop,
1297 * but we do not re-notify the parent if we have
1298 * to loop several times waiting for the parent
1299 * to let us continue.
1302 p->p_flag |= P_STOPPED;
1303 p->p_flag &= ~P_WAITED;
1304 psignal(p->p_pptr, SIGCHLD);
1307 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1308 p->p_flag &= ~P_STOPPED;
1311 * If parent wants us to take the signal,
1312 * then it will leave it in p->p_xstat;
1313 * otherwise we just look for signals again.
1315 SIGDELSET(p->p_siglist, sig); /* clear old signal */
1321 * Put the new signal into p_siglist. If the
1322 * signal is being masked, look for other signals.
1324 SIGADDSET(p->p_siglist, sig);
1325 if (SIGISMEMBER(p->p_sigmask, sig))
1329 * If the traced bit got turned off, go back up
1330 * to the top to rescan signals. This ensures
1331 * that p_sig* and ps_sigact are consistent.
1333 if ((p->p_flag & P_TRACED) == 0)
1337 prop = sigprop(sig);
1340 * Decide whether the signal should be returned.
1341 * Return the signal's number, or fall through
1342 * to clear it from the pending mask.
1344 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1347 * Don't take default actions on system processes.
1349 if (p->p_pid <= 1) {
1352 * Are you sure you want to ignore SIGSEGV
1355 printf("Process (pid %lu) got signal %d\n",
1356 (u_long)p->p_pid, sig);
1358 break; /* == ignore */
1362 * Handle the in-kernel checkpoint action
1364 if (prop & SA_CKPT) {
1365 checkpoint_signal_handler(p);
1370 * If there is a pending stop signal to process
1371 * with default action, stop here,
1372 * then clear the signal. However,
1373 * if process is member of an orphaned
1374 * process group, ignore tty stop signals.
1376 if (prop & SA_STOP) {
1377 if (p->p_flag & P_TRACED ||
1378 (p->p_pgrp->pg_jobc == 0 &&
1380 break; /* == ignore */
1382 p->p_flag |= P_STOPPED;
1383 p->p_flag &= ~P_WAITED;
1385 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0)
1386 psignal(p->p_pptr, SIGCHLD);
1387 while (p->p_flag & P_STOPPED) {
1391 } else if (prop & SA_IGNORE) {
1393 * Except for SIGCONT, shouldn't get here.
1394 * Default action is to ignore; drop it.
1396 break; /* == ignore */
1406 * Masking above should prevent us ever trying
1407 * to take action on an ignored signal other
1408 * than SIGCONT, unless process is traced.
1410 if ((prop & SA_CONT) == 0 &&
1411 (p->p_flag & P_TRACED) == 0)
1412 printf("issignal\n");
1413 break; /* == ignore */
1417 * This signal has an action, let
1418 * postsig() process it.
1423 SIGDELSET(p->p_siglist, sig); /* take the signal! */
1429 * Take the action for the specified signal
1430 * from the current set of pending signals.
1435 struct proc *p = curproc;
1436 struct sigacts *ps = p->p_sigacts;
1438 sigset_t returnmask;
1441 KASSERT(sig != 0, ("postsig"));
1443 SIGDELSET(p->p_siglist, sig);
1444 action = ps->ps_sigact[_SIG_IDX(sig)];
1446 if (KTRPOINT(p->p_thread, KTR_PSIG))
1447 ktrpsig(p, sig, action, p->p_flag & P_OLDMASK ?
1448 &p->p_oldsigmask : &p->p_sigmask, 0);
1450 STOPEVENT(p, S_SIG, sig);
1452 if (action == SIG_DFL) {
1454 * Default action, where the default is to kill
1455 * the process. (Other cases were ignored above.)
1461 * If we get here, the signal must be caught.
1463 KASSERT(action != SIG_IGN && !SIGISMEMBER(p->p_sigmask, sig),
1464 ("postsig action"));
1466 * Set the new mask value and also defer further
1467 * occurrences of this signal.
1469 * Special case: user has done a sigsuspend. Here the
1470 * current mask is not of interest, but rather the
1471 * mask from before the sigsuspend is what we want
1472 * restored after the signal processing is completed.
1475 if (p->p_flag & P_OLDMASK) {
1476 returnmask = p->p_oldsigmask;
1477 p->p_flag &= ~P_OLDMASK;
1479 returnmask = p->p_sigmask;
1482 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
1483 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1484 SIGADDSET(p->p_sigmask, sig);
1486 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1488 * See kern_sigaction() for origin of this code.
1490 SIGDELSET(p->p_sigcatch, sig);
1491 if (sig != SIGCONT &&
1492 sigprop(sig) & SA_IGNORE)
1493 SIGADDSET(p->p_sigignore, sig);
1494 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1497 p->p_stats->p_ru.ru_nsignals++;
1498 if (p->p_sig != sig) {
1505 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
1510 * Kill the current process for stated reason.
1513 killproc(struct proc *p, char *why)
1515 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm,
1516 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1517 psignal(p, SIGKILL);
1521 * Force the current process to exit with the specified signal, dumping core
1522 * if appropriate. We bypass the normal tests for masked and caught signals,
1523 * allowing unrecoverable failures to terminate the process without changing
1524 * signal state. Mark the accounting record with the signal termination.
1525 * If dumping core, save the signal number for the debugger. Calls exit and
1529 sigexit(struct proc *p, int sig)
1531 p->p_acflag |= AXSIG;
1532 if (sigprop(sig) & SA_CORE) {
1535 * Log signals which would cause core dumps
1536 * (Log as LOG_INFO to appease those who don't want
1538 * XXX : Todo, as well as euid, write out ruid too
1540 if (coredump(p) == 0)
1542 if (kern_logsigexit)
1544 "pid %d (%s), uid %d: exited on signal %d%s\n",
1545 p->p_pid, p->p_comm,
1546 p->p_ucred ? p->p_ucred->cr_uid : -1,
1548 sig & WCOREFLAG ? " (core dumped)" : "");
1550 exit1(W_EXITCODE(0, sig));
1554 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
1555 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
1556 sizeof(corefilename), "process corefile name format string");
1559 * expand_name(name, uid, pid)
1560 * Expand the name described in corefilename, using name, uid, and pid.
1561 * corefilename is a printf-like string, with three format specifiers:
1562 * %N name of process ("name")
1563 * %P process id (pid)
1565 * For example, "%N.core" is the default; they can be disabled completely
1566 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
1567 * This is controlled by the sysctl variable kern.corefile (see above).
1571 expand_name(const char *name, uid_t uid, pid_t pid)
1574 char buf[11]; /* Buffer for pid/uid -- max 4B */
1576 char *format = corefilename;
1579 temp = malloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
1582 namelen = strlen(name);
1583 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
1585 switch (format[i]) {
1586 case '%': /* Format character */
1588 switch (format[i]) {
1592 case 'N': /* process name */
1593 if ((n + namelen) > MAXPATHLEN) {
1594 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1595 pid, name, uid, temp, name);
1599 memcpy(temp+n, name, namelen);
1602 case 'P': /* process id */
1603 l = sprintf(buf, "%u", pid);
1604 if ((n + l) > MAXPATHLEN) {
1605 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1606 pid, name, uid, temp, name);
1610 memcpy(temp+n, buf, l);
1613 case 'U': /* user id */
1614 l = sprintf(buf, "%u", uid);
1615 if ((n + l) > MAXPATHLEN) {
1616 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1617 pid, name, uid, temp, name);
1621 memcpy(temp+n, buf, l);
1625 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
1629 temp[n++] = format[i];
1637 * Dump a process' core. The main routine does some
1638 * policy checking, and creates the name of the coredump;
1639 * then it passes on a vnode and a size limit to the process-specific
1640 * coredump routine if there is one; if there _is not_ one, it returns
1641 * ENOSYS; otherwise it returns the error from the process-specific routine.
1645 coredump(struct proc *p)
1648 struct ucred *cred = p->p_ucred;
1650 struct nlookupdata nd;
1653 char *name; /* name of corefile */
1656 STOPEVENT(p, S_CORE, 0);
1658 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
1662 * Note that the bulk of limit checking is done after
1663 * the corefile is created. The exception is if the limit
1664 * for corefiles is 0, in which case we don't bother
1665 * creating the corefile at all. This layout means that
1666 * a corefile is truncated instead of not being created,
1667 * if it is larger than the limit.
1669 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
1673 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
1676 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
1678 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
1685 nd.nl_open_vp = NULL;
1689 lf.l_whence = SEEK_SET;
1692 lf.l_type = F_WRLCK;
1693 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
1697 /* Don't dump to non-regular files or files with links. */
1698 if (vp->v_type != VREG ||
1699 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
1705 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1707 VOP_SETATTR(vp, &vattr, cred);
1708 p->p_acflag |= ACORE;
1711 error = p->p_sysent->sv_coredump ?
1712 p->p_sysent->sv_coredump(p, vp, limit) : ENOSYS;
1715 lf.l_type = F_UNLCK;
1716 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
1718 error1 = vn_close(vp, FWRITE);
1725 * Nonexistent system call-- signal process (may want to handle it).
1726 * Flag error in case process won't see signal immediately (blocked or ignored).
1730 sys_nosys(struct nosys_args *args)
1732 psignal(curproc, SIGSYS);
1737 * Send a SIGIO or SIGURG signal to a process or process group using
1738 * stored credentials rather than those of the current process.
1741 pgsigio(struct sigio *sigio, int sig, int checkctty)
1746 if (sigio->sio_pgid > 0) {
1747 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
1749 psignal(sigio->sio_proc, sig);
1750 } else if (sigio->sio_pgid < 0) {
1753 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist)
1754 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
1755 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
1761 filt_sigattach(struct knote *kn)
1763 struct proc *p = curproc;
1765 kn->kn_ptr.p_proc = p;
1766 kn->kn_flags |= EV_CLEAR; /* automatically set */
1768 /* XXX lock the proc here while adding to the list? */
1769 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
1775 filt_sigdetach(struct knote *kn)
1777 struct proc *p = kn->kn_ptr.p_proc;
1779 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
1783 * signal knotes are shared with proc knotes, so we apply a mask to
1784 * the hint in order to differentiate them from process hints. This
1785 * could be avoided by using a signal-specific knote list, but probably
1786 * isn't worth the trouble.
1789 filt_signal(struct knote *kn, long hint)
1791 if (hint & NOTE_SIGNAL) {
1792 hint &= ~NOTE_SIGNAL;
1794 if (kn->kn_id == hint)
1797 return (kn->kn_data != 0);