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34 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
35 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $
38 #include "opt_ktrace.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/sysmsg.h>
44 #include <sys/signalvar.h>
45 #include <sys/resourcevar.h>
46 #include <sys/vnode.h>
47 #include <sys/event.h>
49 #include <sys/nlookup.h>
50 #include <sys/pioctl.h>
52 #include <sys/fcntl.h>
55 #include <sys/ktrace.h>
56 #include <sys/syslog.h>
58 #include <sys/sysent.h>
59 #include <sys/sysctl.h>
60 #include <sys/malloc.h>
61 #include <sys/interrupt.h>
62 #include <sys/unistd.h>
63 #include <sys/kern_syscall.h>
64 #include <sys/vkernel.h>
66 #include <sys/signal2.h>
67 #include <sys/thread2.h>
68 #include <sys/spinlock2.h>
70 #include <machine/cpu.h>
71 #include <machine/smp.h>
73 static int coredump(struct lwp *, int);
74 static char *expand_name(const char *, uid_t, pid_t);
75 static int dokillpg(int sig, int pgid, int all);
76 static int sig_ffs(sigset_t *set);
77 static int sigprop(int sig);
78 static void lwp_signotify(struct lwp *lp);
79 static void lwp_signotify_remote(void *arg);
80 static int kern_sigtimedwait(sigset_t set, siginfo_t *info,
81 struct timespec *timeout);
82 static void proc_stopwait(struct proc *p);
84 static int filt_sigattach(struct knote *kn);
85 static void filt_sigdetach(struct knote *kn);
86 static int filt_signal(struct knote *kn, long hint);
88 struct filterops sig_filtops =
89 { FILTEROP_MPSAFE, filt_sigattach, filt_sigdetach, filt_signal };
91 static int kern_logsigexit = 1;
92 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
94 "Log processes quitting on abnormal signals to syslog(3)");
97 * Can process p send the signal sig to process q? Only processes within
98 * the current reaper or children of the current reaper can be signaled.
99 * Normally the reaper itself cannot be signalled, unless initok is set.
101 #define CANSIGNAL(q, sig, initok) \
102 ((!p_trespass(curproc->p_ucred, (q)->p_ucred) && \
103 reaper_sigtest(curproc, p, initok)) || \
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 */
207 __read_mostly sigset_t sigcantmask_mask;
213 if (sig > 0 && sig < NSIG)
214 return (sigproptbl[_SIG_IDX(sig)]);
220 sig_ffs(sigset_t *set)
224 for (i = 0; i < _SIG_WORDS; i++)
226 return (ffs(set->__bits[i]) + (i * 32));
231 * Allows us to populate siginfo->si_pid and si_uid in the target process
232 * (p) from the originating thread (td). This function must work properly
233 * even if a kernel thread is sending the signal.
235 * NOTE: Signals are not queued, so if multiple signals are received the
236 * signal handler will only see the most recent pid and uid for any
237 * given signal number.
240 sigsetfrompid(thread_t td, struct proc *p, int sig)
244 if ((sap = p->p_sigacts) == NULL)
247 sap->ps_frominfo[sig].pid = td->td_proc->p_pid;
248 sap->ps_frominfo[sig].uid = td->td_ucred->cr_uid;
250 sap->ps_frominfo[sig].pid = 0;
251 sap->ps_frominfo[sig].uid = 0;
259 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact)
261 struct thread *td = curthread;
262 struct proc *p = td->td_proc;
264 struct sigacts *ps = p->p_sigacts;
266 if (sig <= 0 || sig > _SIG_MAXSIG)
269 lwkt_gettoken(&p->p_token);
272 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
273 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
275 if (SIGISMEMBER(ps->ps_sigonstack, sig))
276 oact->sa_flags |= SA_ONSTACK;
277 if (!SIGISMEMBER(ps->ps_sigintr, sig))
278 oact->sa_flags |= SA_RESTART;
279 if (SIGISMEMBER(ps->ps_sigreset, sig))
280 oact->sa_flags |= SA_RESETHAND;
281 if (SIGISMEMBER(ps->ps_signodefer, sig))
282 oact->sa_flags |= SA_NODEFER;
283 if (SIGISMEMBER(ps->ps_siginfo, sig))
284 oact->sa_flags |= SA_SIGINFO;
285 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP)
286 oact->sa_flags |= SA_NOCLDSTOP;
287 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT)
288 oact->sa_flags |= SA_NOCLDWAIT;
292 * Check for invalid requests. KILL and STOP cannot be
295 if (sig == SIGKILL || sig == SIGSTOP) {
296 if (act->sa_handler != SIG_DFL) {
297 lwkt_reltoken(&p->p_token);
303 * Change setting atomically.
305 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
306 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
307 if (act->sa_flags & SA_SIGINFO) {
308 ps->ps_sigact[_SIG_IDX(sig)] =
309 (__sighandler_t *)act->sa_sigaction;
310 SIGADDSET(ps->ps_siginfo, sig);
312 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
313 SIGDELSET(ps->ps_siginfo, sig);
315 if (!(act->sa_flags & SA_RESTART))
316 SIGADDSET(ps->ps_sigintr, sig);
318 SIGDELSET(ps->ps_sigintr, sig);
319 if (act->sa_flags & SA_ONSTACK)
320 SIGADDSET(ps->ps_sigonstack, sig);
322 SIGDELSET(ps->ps_sigonstack, sig);
323 if (act->sa_flags & SA_RESETHAND)
324 SIGADDSET(ps->ps_sigreset, sig);
326 SIGDELSET(ps->ps_sigreset, sig);
327 if (act->sa_flags & SA_NODEFER)
328 SIGADDSET(ps->ps_signodefer, sig);
330 SIGDELSET(ps->ps_signodefer, sig);
331 if (sig == SIGCHLD) {
332 if (act->sa_flags & SA_NOCLDSTOP)
333 p->p_sigacts->ps_flag |= PS_NOCLDSTOP;
335 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP;
336 if (act->sa_flags & SA_NOCLDWAIT) {
338 * Paranoia: since SA_NOCLDWAIT is implemented
339 * by reparenting the dying child to PID 1 (and
340 * trust it to reap the zombie), PID 1 itself
341 * is forbidden to set SA_NOCLDWAIT.
344 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
346 p->p_sigacts->ps_flag |= PS_NOCLDWAIT;
348 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
350 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
351 ps->ps_flag |= PS_CLDSIGIGN;
353 ps->ps_flag &= ~PS_CLDSIGIGN;
356 * Set bit in p_sigignore for signals that are set to SIG_IGN,
357 * and for signals set to SIG_DFL where the default is to
358 * ignore. However, don't put SIGCONT in p_sigignore, as we
359 * have to restart the process.
361 * Also remove the signal from the process and lwp signal
364 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
365 (sigprop(sig) & SA_IGNORE &&
366 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
367 SIGDELSET_ATOMIC(p->p_siglist, sig);
368 FOREACH_LWP_IN_PROC(lp, p) {
369 spin_lock(&lp->lwp_spin);
370 SIGDELSET(lp->lwp_siglist, sig);
371 spin_unlock(&lp->lwp_spin);
373 if (sig != SIGCONT) {
374 /* easier in ksignal */
375 SIGADDSET(p->p_sigignore, sig);
377 SIGDELSET(p->p_sigcatch, sig);
379 SIGDELSET(p->p_sigignore, sig);
380 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
381 SIGDELSET(p->p_sigcatch, sig);
383 SIGADDSET(p->p_sigcatch, sig);
386 lwkt_reltoken(&p->p_token);
391 sys_sigaction(struct sysmsg *sysmsg, const struct sigaction_args *uap)
393 struct sigaction act, oact;
394 struct sigaction *actp, *oactp;
397 actp = (uap->act != NULL) ? &act : NULL;
398 oactp = (uap->oact != NULL) ? &oact : NULL;
400 error = copyin(uap->act, actp, sizeof(act));
404 error = kern_sigaction(uap->sig, actp, oactp);
405 if (oactp && !error) {
406 error = copyout(oactp, uap->oact, sizeof(oact));
412 * Initialize signal state for process 0;
413 * set to ignore signals that are ignored by default.
416 siginit(struct proc *p)
420 for (i = 1; i <= NSIG; i++) {
421 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
422 SIGADDSET(p->p_sigignore, i);
426 * Also initialize signal-related global state.
428 SIGSETOR_CANTMASK(sigcantmask_mask);
432 * Reset signals for an exec of the specified process.
435 execsigs(struct proc *p)
437 struct sigacts *ps = p->p_sigacts;
441 lp = ONLY_LWP_IN_PROC(p);
444 * Reset caught signals. Held signals remain held
445 * through p_sigmask (unless they were caught,
446 * and are now ignored by default).
448 while (SIGNOTEMPTY(p->p_sigcatch)) {
449 sig = sig_ffs(&p->p_sigcatch);
450 SIGDELSET(p->p_sigcatch, sig);
451 if (sigprop(sig) & SA_IGNORE) {
453 SIGADDSET(p->p_sigignore, sig);
454 SIGDELSET_ATOMIC(p->p_siglist, sig);
455 /* don't need spinlock */
456 SIGDELSET(lp->lwp_siglist, sig);
458 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
462 * Reset stack state to the user stack.
463 * Clear set of signals caught on the signal stack.
465 lp->lwp_sigstk.ss_flags = SS_DISABLE;
466 lp->lwp_sigstk.ss_size = 0;
467 lp->lwp_sigstk.ss_sp = NULL;
468 lp->lwp_flags &= ~LWP_ALTSTACK;
470 * Reset no zombies if child dies flag as Solaris does.
472 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
473 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
474 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
478 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
480 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
484 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
486 struct thread *td = curthread;
487 struct lwp *lp = td->td_lwp;
488 struct proc *p = td->td_proc;
491 lwkt_gettoken(&p->p_token);
494 *oset = lp->lwp_sigmask;
501 SIGSETOR(lp->lwp_sigmask, *set);
504 SIGSETNAND(lp->lwp_sigmask, *set);
508 lp->lwp_sigmask = *set;
516 lwkt_reltoken(&p->p_token);
527 sys_sigprocmask(struct sysmsg *sysmsg, const struct sigprocmask_args *uap)
530 sigset_t *setp, *osetp;
533 setp = (uap->set != NULL) ? &set : NULL;
534 osetp = (uap->oset != NULL) ? &oset : NULL;
536 error = copyin(uap->set, setp, sizeof(set));
540 error = kern_sigprocmask(uap->how, setp, osetp);
541 if (osetp && !error) {
542 error = copyout(osetp, uap->oset, sizeof(oset));
551 kern_sigpending(sigset_t *set)
553 struct lwp *lp = curthread->td_lwp;
555 *set = lwp_sigpend(lp);
564 sys_sigpending(struct sysmsg *sysmsg, const struct sigpending_args *uap)
569 error = kern_sigpending(&set);
572 error = copyout(&set, uap->set, sizeof(set));
577 * Suspend process until signal, providing mask to be set
583 kern_sigsuspend(sigset_t *set)
585 struct thread *td = curthread;
586 struct lwp *lp = td->td_lwp;
587 struct proc *p = td->td_proc;
588 struct sigacts *ps = p->p_sigacts;
591 * When returning from sigsuspend, we want
592 * the old mask to be restored after the
593 * signal handler has finished. Thus, we
594 * save it here and mark the sigacts structure
597 lp->lwp_oldsigmask = lp->lwp_sigmask;
598 lp->lwp_flags |= LWP_OLDMASK;
601 lp->lwp_sigmask = *set;
602 while (tsleep(ps, PCATCH, "pause", 0) == 0)
604 /* always return EINTR rather than ERESTART... */
609 * Note nonstandard calling convention: libc stub passes mask, not
610 * pointer, to save a copyin.
615 sys_sigsuspend(struct sysmsg *sysmsg, const struct sigsuspend_args *uap)
620 error = copyin(uap->sigmask, &mask, sizeof(mask));
624 error = kern_sigsuspend(&mask);
633 kern_sigaltstack(stack_t *ss, stack_t *oss)
635 struct thread *td = curthread;
636 struct lwp *lp = td->td_lwp;
637 struct proc *p = td->td_proc;
639 if ((lp->lwp_flags & LWP_ALTSTACK) == 0)
640 lp->lwp_sigstk.ss_flags |= SS_DISABLE;
643 *oss = lp->lwp_sigstk;
646 if (ss->ss_flags & ~SS_DISABLE)
648 if (ss->ss_flags & SS_DISABLE) {
649 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK)
651 lp->lwp_flags &= ~LWP_ALTSTACK;
652 lp->lwp_sigstk.ss_flags = ss->ss_flags;
654 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
656 lp->lwp_flags |= LWP_ALTSTACK;
657 lp->lwp_sigstk = *ss;
668 sys_sigaltstack(struct sysmsg *sysmsg, const struct sigaltstack_args *uap)
674 error = copyin(uap->ss, &ss, sizeof(ss));
679 error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL);
681 if (error == 0 && uap->oss)
682 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
687 * Common code for kill process group/broadcast kill.
688 * cp is calling process.
695 static int killpg_all_callback(struct proc *p, void *data);
698 dokillpg(int sig, int pgid, int all)
700 struct killpg_info info;
701 struct proc *cp = curproc;
712 allproc_scan(killpg_all_callback, &info, 0);
716 * zero pgid means send to my process group.
727 * Must interlock all signals against fork
729 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
730 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
732 p->p_stat == SZOMB ||
733 (p->p_flags & P_SYSTEM) ||
734 !CANSIGNAL(p, sig, 0)) {
741 lockmgr(&pgrp->pg_lock, LK_RELEASE);
744 return (info.nfound ? 0 : ESRCH);
748 killpg_all_callback(struct proc *p, void *data)
750 struct killpg_info *info = data;
752 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) ||
753 p == curproc || !CANSIGNAL(p, info->sig, 0)) {
758 ksignal(p, info->sig);
763 * Send a general signal to a process or LWPs within that process.
765 * Note that new signals cannot be sent if a process is exiting or already
766 * a zombie, but we return success anyway as userland is likely to not handle
772 kern_kill(int sig, pid_t pid, lwpid_t tid)
776 if ((u_int)sig > _SIG_MAXSIG)
781 struct lwp *lp = NULL;
784 * Send a signal to a single process. If the kill() is
785 * racing an exiting process which has not yet been reaped
786 * act as though the signal was delivered successfully but
787 * don't actually try to deliver the signal.
789 if ((p = pfind(pid)) == NULL) {
790 if ((p = zpfind(pid)) == NULL)
796 lwkt_gettoken_shared(&p->p_token);
797 if (!CANSIGNAL(p, sig, 1)) {
798 lwkt_reltoken(&p->p_token);
802 lwkt_reltoken(&p->p_token);
806 * NOP if the process is exiting. Note that lwpsignal() is
807 * called directly with P_WEXIT set to kill individual LWPs
808 * during exit, which is allowed.
810 if (p->p_flags & P_WEXIT) {
815 lwkt_gettoken_shared(&p->p_token);
816 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid);
818 lwkt_reltoken(&p->p_token);
823 lwkt_reltoken(&p->p_token);
826 lwpsignal(p, lp, sig);
835 * If we come here, pid is a special broadcast pid.
836 * This doesn't mix with a tid.
842 case -1: /* broadcast signal */
843 t = (dokillpg(sig, 0, 1));
845 case 0: /* signal own process group */
846 t = (dokillpg(sig, 0, 0));
848 default: /* negative explicit process group */
849 t = (dokillpg(sig, -pid, 0));
856 sys_kill(struct sysmsg *sysmsg, const struct kill_args *uap)
860 error = kern_kill(uap->signum, uap->pid, -1);
865 sys_lwp_kill(struct sysmsg *sysmsg, const struct lwp_kill_args *uap)
868 pid_t pid = uap->pid;
871 * A tid is mandatory for lwp_kill(), otherwise
872 * you could simply use kill().
878 * To save on a getpid() function call for intra-process
879 * signals, pid == -1 means current process.
882 pid = curproc->p_pid;
884 error = kern_kill(uap->signum, pid, uap->tid);
889 * Send a signal to a process group.
892 gsignal(int pgid, int sig)
896 if (pgid && (pgrp = pgfind(pgid)))
897 pgsignal(pgrp, sig, 0);
901 * Send a signal to a process group. If checktty is 1,
902 * limit to members which have a controlling terminal.
904 * pg_lock interlocks against a fork that might be in progress, to
905 * ensure that the new child process picks up the signal.
908 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
913 * Must interlock all signals against fork
917 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
918 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
919 if (checkctty == 0 || p->p_flags & P_CONTROLT)
922 lockmgr(&pgrp->pg_lock, LK_RELEASE);
928 * Send a signal caused by a trap to the current lwp. If it will be caught
929 * immediately, deliver it with correct code. Otherwise, post it normally.
931 * These signals may ONLY be delivered to the specified lwp and may never
932 * be delivered to the process generically.
934 * lpmap->blockallsigs is ignored.
937 trapsignal(struct lwp *lp, int sig, u_long code)
939 struct proc *p = lp->lwp_proc;
940 struct sigacts *ps = p->p_sigacts;
943 * If we are a virtual kernel running an emulated user process
944 * context, switch back to the virtual kernel context before
945 * trying to post the signal.
947 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
948 struct trapframe *tf = lp->lwp_md.md_regs;
950 vkernel_trap(lp, tf);
953 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
954 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
955 lp->lwp_ru.ru_nsignals++;
957 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
958 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)],
959 &lp->lwp_sigmask, code);
961 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
962 &lp->lwp_sigmask, code);
963 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
964 if (!SIGISMEMBER(ps->ps_signodefer, sig))
965 SIGADDSET(lp->lwp_sigmask, sig);
966 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
968 * See kern_sigaction() for origin of this code.
970 SIGDELSET(p->p_sigcatch, sig);
971 if (sig != SIGCONT &&
972 sigprop(sig) & SA_IGNORE)
973 SIGADDSET(p->p_sigignore, sig);
974 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
977 lp->lwp_code = code; /* XXX for core dump/debugger */
978 lp->lwp_sig = sig; /* XXX to verify code */
979 lwpsignal(p, lp, sig);
984 * Find a suitable lwp to deliver the signal to. Returns NULL if all
985 * lwps hold the signal blocked.
987 * Caller must hold p->p_token.
989 * Returns a lp or NULL. If non-NULL the lp is held and its token is
993 find_lwp_for_signal(struct proc *p, int sig)
996 struct lwp *run, *sleep, *stop;
999 * If the running/preempted thread belongs to the proc to which
1000 * the signal is being delivered and this thread does not block
1001 * the signal, then we can avoid a context switch by delivering
1002 * the signal to this thread, because it will return to userland
1005 lp = lwkt_preempted_proc();
1006 if (lp != NULL && lp->lwp_proc == p) {
1008 lwkt_gettoken(&lp->lwp_token);
1009 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) {
1010 /* return w/ token held */
1013 lwkt_reltoken(&lp->lwp_token);
1017 run = sleep = stop = NULL;
1018 FOREACH_LWP_IN_PROC(lp, p) {
1020 * If the signal is being blocked by the lwp, then this
1021 * lwp is not eligible for receiving the signal.
1024 lwkt_gettoken(&lp->lwp_token);
1026 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
1027 lwkt_reltoken(&lp->lwp_token);
1032 switch (lp->lwp_stat) {
1036 lwkt_reltoken(&sleep->lwp_token);
1042 lwkt_reltoken(&stop->lwp_token);
1051 if (lp->lwp_flags & LWP_SINTR) {
1053 lwkt_reltoken(&lp->lwp_token);
1057 lwkt_reltoken(&stop->lwp_token);
1065 lwkt_reltoken(&lp->lwp_token);
1071 lwkt_reltoken(&lp->lwp_token);
1074 lwkt_reltoken(&lp->lwp_token);
1087 else if (sleep != NULL)
1094 * Send the signal to the process. If the signal has an action, the action
1095 * is usually performed by the target process rather than the caller; we add
1096 * the signal to the set of pending signals for the process.
1099 * o When a stop signal is sent to a sleeping process that takes the
1100 * default action, the process is stopped without awakening it.
1101 * o SIGCONT restarts stopped processes (or puts them back to sleep)
1102 * regardless of the signal action (eg, blocked or ignored).
1104 * Other ignored signals are discarded immediately.
1106 * If the caller wishes to call this function from a hard code section the
1107 * caller must already hold p->p_token (see kern_clock.c).
1112 ksignal(struct proc *p, int sig)
1114 lwpsignal(p, NULL, sig);
1118 * The core for ksignal. lp may be NULL, then a suitable thread
1119 * will be chosen. If not, lp MUST be a member of p.
1121 * If the caller wishes to call this function from a hard code section the
1122 * caller must already hold p->p_token.
1127 lwpsignal(struct proc *p, struct lwp *lp, int sig)
1133 if (sig > _SIG_MAXSIG || sig <= 0) {
1134 kprintf("lwpsignal: signal %d\n", sig);
1135 panic("lwpsignal signal number");
1138 KKASSERT(lp == NULL || lp->lwp_proc == p);
1141 * We don't want to race... well, all sorts of things. Get appropriate
1144 * Don't try to deliver a generic signal to an exiting process,
1145 * the signal structures could be in flux. We check the LWP later
1151 lwkt_gettoken(&lp->lwp_token);
1153 lwkt_gettoken(&p->p_token);
1154 if (p->p_flags & P_WEXIT)
1158 prop = sigprop(sig);
1161 * If proc is traced, always give parent a chance;
1162 * if signal event is tracked by procfs, give *that*
1163 * a chance, as well.
1165 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) {
1169 * Do not try to deliver signals to an exiting lwp other
1170 * than SIGKILL. Note that we must still deliver the signal
1171 * if P_WEXIT is set in the process flags.
1173 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) {
1174 lwkt_reltoken(&lp->lwp_token);
1181 * If the signal is being ignored, then we forget about
1182 * it immediately. NOTE: We don't set SIGCONT in p_sigignore,
1183 * and if it is set to SIG_IGN, action will be SIG_DFL here.
1185 if (SIGISMEMBER(p->p_sigignore, sig)) {
1187 * Even if a signal is set SIG_IGN, it may still be
1188 * lurking in a kqueue.
1190 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1192 lwkt_reltoken(&lp->lwp_token);
1195 lwkt_reltoken(&p->p_token);
1200 if (SIGISMEMBER(p->p_sigcatch, sig))
1207 * If continuing, clear any pending STOP signals for the whole
1210 if (prop & SA_CONT) {
1211 lwkt_gettoken(&p->p_token);
1212 SIG_STOPSIGMASK_ATOMIC(p->p_siglist);
1213 lwkt_reltoken(&p->p_token);
1216 if (prop & SA_STOP) {
1218 * If sending a tty stop signal to a member of an orphaned
1219 * process group, discard the signal here if the action
1220 * is default; don't stop the process below if sleeping,
1221 * and don't clear any pending SIGCONT.
1223 if ((prop & SA_TTYSTOP) && p->p_pgrp->pg_jobc == 0 &&
1224 action == SIG_DFL) {
1226 lwkt_reltoken(&lp->lwp_token);
1229 lwkt_reltoken(&p->p_token);
1234 lwkt_gettoken(&p->p_token);
1235 SIG_CONTSIGMASK_ATOMIC(p->p_siglist);
1236 p->p_flags &= ~P_CONTINUED;
1237 lwkt_reltoken(&p->p_token);
1240 if (p->p_stat == SSTOP) {
1242 * Nobody can handle this signal, add it to the lwp or
1243 * process pending list
1245 lwkt_gettoken(&p->p_token);
1246 if (p->p_stat != SSTOP) {
1247 lwkt_reltoken(&p->p_token);
1250 sigsetfrompid(curthread, p, sig);
1252 spin_lock(&lp->lwp_spin);
1253 SIGADDSET(lp->lwp_siglist, sig);
1254 spin_unlock(&lp->lwp_spin);
1256 SIGADDSET_ATOMIC(p->p_siglist, sig);
1260 * If the process is stopped and is being traced, then no
1261 * further action is necessary.
1263 if (p->p_flags & P_TRACED) {
1264 lwkt_reltoken(&p->p_token);
1269 * If the process is stopped and receives a KILL signal,
1270 * make the process runnable.
1272 if (sig == SIGKILL) {
1273 proc_unstop(p, SSTOP);
1274 lwkt_reltoken(&p->p_token);
1275 goto active_process;
1279 * If the process is stopped and receives a CONT signal,
1280 * then try to make the process runnable again.
1282 if (prop & SA_CONT) {
1284 * If SIGCONT is default (or ignored), we continue the
1285 * process but don't leave the signal in p_siglist, as
1286 * it has no further action. If SIGCONT is held, we
1287 * continue the process and leave the signal in
1288 * p_siglist. If the process catches SIGCONT, let it
1289 * handle the signal itself.
1291 * XXX what if the signal is being held blocked?
1293 * Token required to interlock kern_wait().
1294 * Reparenting can also cause a race so we have to
1299 lwkt_gettoken(&q->p_token);
1300 p->p_flags |= P_CONTINUED;
1302 if (action == SIG_DFL)
1303 SIGDELSET_ATOMIC(p->p_siglist, sig);
1304 proc_unstop(p, SSTOP);
1305 lwkt_reltoken(&q->p_token);
1307 lwkt_reltoken(&p->p_token);
1308 if (action == SIG_CATCH)
1309 goto active_process;
1314 * If the process is stopped and receives another STOP
1315 * signal, we do not need to stop it again. If we did
1316 * the shell could get confused.
1318 * However, if the current/preempted lwp is part of the
1319 * process receiving the signal, we need to keep it,
1320 * so that this lwp can stop in issignal() later, as
1321 * we don't want to wait until it reaches userret!
1323 if (prop & SA_STOP) {
1324 if (lwkt_preempted_proc() == NULL ||
1325 lwkt_preempted_proc()->lwp_proc != p) {
1326 SIGDELSET_ATOMIC(p->p_siglist, sig);
1331 * Otherwise the process is stopped and it received some
1332 * signal, which does not change its stopped state. When
1333 * the process is continued a wakeup(p) will be issued which
1334 * will wakeup any threads sleeping in tstop().
1336 lwkt_reltoken(&p->p_token);
1342 /* else not stopped */
1346 * Never deliver a lwp-specific signal to a random lwp.
1349 /* NOTE: returns lp w/ token held */
1350 lp = find_lwp_for_signal(p, sig);
1352 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
1353 lwkt_reltoken(&lp->lwp_token);
1356 /* maintain proc token */
1359 lwkt_reltoken(&p->p_token);
1360 /* maintain lp token */
1366 * Deliver to the process generically if (1) the signal is being
1367 * sent to any thread or (2) we could not find a thread to deliver
1371 sigsetfrompid(curthread, p, sig);
1372 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1373 SIGADDSET_ATOMIC(p->p_siglist, sig);
1378 * Deliver to a specific LWP whether it masks it or not. It will
1379 * not be dispatched if masked but we must still deliver it.
1381 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1382 (p->p_flags & P_TRACED) == 0) {
1383 lwkt_gettoken(&p->p_token);
1385 lwkt_reltoken(&p->p_token);
1389 * If the process receives a STOP signal which indeed needs to
1390 * stop the process, do so. If the process chose to catch the
1391 * signal, it will be treated like any other signal.
1393 if ((prop & SA_STOP) && action == SIG_DFL) {
1395 * If a child holding parent blocked, stopping
1396 * could cause deadlock. Take no action at this
1399 lwkt_gettoken(&p->p_token);
1400 if (p->p_flags & P_PPWAIT) {
1401 sigsetfrompid(curthread, p, sig);
1402 SIGADDSET_ATOMIC(p->p_siglist, sig);
1403 lwkt_reltoken(&p->p_token);
1408 * Do not actually try to manipulate the process, but simply
1409 * stop it. Lwps will stop as soon as they safely can.
1411 * Ignore stop if the process is exiting.
1413 if ((p->p_flags & P_WEXIT) == 0) {
1415 proc_stop(p, SSTOP);
1417 lwkt_reltoken(&p->p_token);
1422 * If it is a CONT signal with default action, just ignore it.
1424 if ((prop & SA_CONT) && action == SIG_DFL)
1428 * Mark signal pending at this specific thread.
1430 sigsetfrompid(curthread, p, sig);
1431 spin_lock(&lp->lwp_spin);
1432 SIGADDSET(lp->lwp_siglist, sig);
1433 spin_unlock(&lp->lwp_spin);
1439 lwkt_reltoken(&lp->lwp_token);
1442 lwkt_reltoken(&p->p_token);
1448 * Notify the LWP that a signal has arrived. The LWP does not have to be
1449 * sleeping on the current cpu.
1451 * p->p_token and lp->lwp_token must be held on call.
1453 * We can only safely schedule the thread on its current cpu and only if
1454 * one of the SINTR flags is set. If an SINTR flag is set AND we are on
1455 * the correct cpu we are properly interlocked, otherwise we could be
1456 * racing other thread transition states (or the lwp is on the user scheduler
1457 * runq but not scheduled) and must not do anything.
1459 * Since we hold the lwp token we know the lwp cannot be ripped out from
1460 * under us so we can safely hold it to prevent it from being ripped out
1461 * from under us if we are forced to IPI another cpu to make the local
1464 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token,
1465 * which we won't in an IPI so any fixups have to be done here, effectively
1466 * replicating part of what setrunnable() does.
1469 lwp_signotify(struct lwp *lp)
1473 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token);
1474 dtd = lp->lwp_thread;
1477 if (lp == lwkt_preempted_proc()) {
1479 * lwp is on the current cpu AND it is currently running
1480 * (we preempted it).
1483 } else if (lp->lwp_flags & LWP_SINTR) {
1485 * lwp is sitting in tsleep() with PCATCH set
1487 if (dtd->td_gd == mycpu) {
1491 * We can only adjust lwp_stat while we hold the
1492 * lwp_token, and we won't in the IPI function.
1495 if (lp->lwp_stat == LSSTOP)
1496 lp->lwp_stat = LSSLEEP;
1497 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1499 } else if (dtd->td_flags & TDF_SINTR) {
1501 * lwp is sitting in lwkt_sleep() with PCATCH set.
1503 if (dtd->td_gd == mycpu) {
1507 * We can only adjust lwp_stat while we hold the
1508 * lwp_token, and we won't in the IPI function.
1511 if (lp->lwp_stat == LSSTOP)
1512 lp->lwp_stat = LSSLEEP;
1513 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1517 * Otherwise the lwp is either in some uninterruptible state
1518 * or it is on the userland scheduler's runqueue waiting to
1519 * be scheduled to a cpu, or it is running in userland. We
1520 * generally want to send an IPI so a running target gets the
1521 * signal ASAP, otherwise a scheduler-tick worth of latency
1524 * Issue an IPI to the remote cpu to knock it into the kernel,
1525 * remote cpu will issue the cpu-local signotify() if the IPI
1526 * preempts the desired thread.
1528 if (dtd->td_gd != mycpu) {
1530 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1537 * This function is called via an IPI so we cannot call setrunnable() here
1538 * (because while we hold the lp we don't own its token, and can't get it
1541 * We are interlocked by virtue of being on the same cpu as the target. If
1542 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule
1543 * the target thread.
1546 lwp_signotify_remote(void *arg)
1548 struct lwp *lp = arg;
1549 thread_t td = lp->lwp_thread;
1551 if (lp == lwkt_preempted_proc()) {
1554 } else if (td->td_gd == mycpu) {
1555 if ((lp->lwp_flags & LWP_SINTR) ||
1556 (td->td_flags & TDF_SINTR)) {
1561 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp);
1562 /* LWPHOLD() is forwarded to the target cpu */
1567 * Caller must hold p->p_token
1570 proc_stop(struct proc *p, int sig)
1575 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1578 * If somebody raced us, be happy with it. SCORE overrides SSTOP.
1581 if (p->p_stat == SCORE || p->p_stat == SZOMB)
1584 if (p->p_stat == SSTOP || p->p_stat == SCORE ||
1585 p->p_stat == SZOMB) {
1591 FOREACH_LWP_IN_PROC(lp, p) {
1593 lwkt_gettoken(&lp->lwp_token);
1595 switch (lp->lwp_stat) {
1598 * Do nothing, we are already counted in
1605 * We're sleeping, but we will stop before
1606 * returning to userspace, so count us
1607 * as stopped as well. We set LWP_MP_WSTOP
1608 * to signal the lwp that it should not
1609 * increase p_nstopped when reaching tstop().
1611 * LWP_MP_WSTOP is protected by lp->lwp_token.
1613 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) {
1614 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP);
1621 * We might notify ourself, but that's not
1627 lwkt_reltoken(&lp->lwp_token);
1631 if (p->p_nstopped == p->p_nthreads) {
1633 * Token required to interlock kern_wait(). Reparenting can
1634 * also cause a race so we have to hold (q).
1638 lwkt_gettoken(&q->p_token);
1639 p->p_flags &= ~P_WAITED;
1641 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1642 ksignal(p->p_pptr, SIGCHLD);
1643 lwkt_reltoken(&q->p_token);
1649 * Caller must hold p_token
1652 proc_unstop(struct proc *p, int sig)
1656 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1658 if (p->p_stat != sig)
1661 p->p_stat = SACTIVE;
1663 FOREACH_LWP_IN_PROC(lp, p) {
1665 lwkt_gettoken(&lp->lwp_token);
1667 switch (lp->lwp_stat) {
1670 * Uh? Not stopped? Well, I guess that's okay.
1673 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1674 p->p_pid, lp->lwp_tid);
1679 * Still sleeping. Don't bother waking it up.
1680 * However, if this thread was counted as
1681 * stopped, undo this.
1683 * Nevertheless we call setrunnable() so that it
1684 * will wake up in case a signal or timeout arrived
1687 * LWP_MP_WSTOP is protected by lp->lwp_token.
1689 if (lp->lwp_mpflags & LWP_MP_WSTOP) {
1690 atomic_clear_int(&lp->lwp_mpflags,
1695 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n",
1696 p->p_pid, lp->lwp_tid);
1702 * This handles any lwp's waiting in a tsleep with
1709 lwkt_reltoken(&lp->lwp_token);
1714 * This handles any lwp's waiting in tstop(). We have interlocked
1715 * the setting of p_stat by acquiring and releasing each lpw's
1722 * Wait for all threads except the current thread to stop.
1725 proc_stopwait(struct proc *p)
1727 while ((p->p_stat == SSTOP || p->p_stat == SCORE) &&
1728 p->p_nstopped < p->p_nthreads - 1) {
1729 tsleep_interlock(&p->p_nstopped, 0);
1730 if (p->p_nstopped < p->p_nthreads - 1) {
1731 tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz);
1740 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1742 sigset_t savedmask, set;
1743 struct proc *p = curproc;
1744 struct lwp *lp = curthread->td_lwp;
1745 int error, sig, hz, timevalid = 0;
1746 struct timespec rts, ets, ts;
1751 ets.tv_sec = 0; /* silence compiler warning */
1752 ets.tv_nsec = 0; /* silence compiler warning */
1753 SIG_CANTMASK(waitset);
1754 savedmask = lp->lwp_sigmask;
1757 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1758 timeout->tv_nsec < 1000000000) {
1760 getnanouptime(&rts);
1761 timespecadd(&rts, timeout, &ets);
1766 set = lwp_sigpend(lp);
1767 SIGSETAND(set, waitset);
1768 if ((sig = sig_ffs(&set)) != 0) {
1769 SIGFILLSET(lp->lwp_sigmask);
1770 SIGDELSET(lp->lwp_sigmask, sig);
1771 SIG_CANTMASK(lp->lwp_sigmask);
1772 sig = issignal(lp, 1, 0);
1774 * It may be a STOP signal, in the case, issignal
1775 * returns 0, because we may stop there, and new
1776 * signal can come in, we should restart if we got
1786 * Previous checking got nothing, and we retried but still
1787 * got nothing, we should return the error status.
1793 * POSIX says this must be checked after looking for pending
1797 if (timevalid == 0) {
1801 getnanouptime(&rts);
1802 if (timespeccmp(&rts, &ets, >=)) {
1806 timespecsub(&ets, &rts, &ts);
1807 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1808 hz = tvtohz_high(&tv);
1813 lp->lwp_sigmask = savedmask;
1814 SIGSETNAND(lp->lwp_sigmask, waitset);
1816 * We won't ever be woken up. Instead, our sleep will
1817 * be broken in lwpsignal().
1819 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1821 if (error == ERESTART) {
1822 /* can not restart a timeout wait. */
1824 } else if (error == EAGAIN) {
1825 /* will calculate timeout by ourself. */
1832 lp->lwp_sigmask = savedmask;
1835 bzero(info, sizeof(*info));
1836 info->si_signo = sig;
1837 spin_lock(&lp->lwp_spin);
1838 lwp_delsig(lp, sig, 1); /* take the signal! */
1839 spin_unlock(&lp->lwp_spin);
1841 if (sig == SIGKILL) {
1854 sys_sigtimedwait(struct sysmsg *sysmsg, const struct sigtimedwait_args *uap)
1857 struct timespec *timeout;
1863 error = copyin(uap->timeout, &ts, sizeof(ts));
1870 error = copyin(uap->set, &set, sizeof(set));
1873 error = kern_sigtimedwait(set, &info, timeout);
1877 error = copyout(&info, uap->info, sizeof(info));
1878 /* Repost if we got an error. */
1882 * This could transform a thread-specific signal to another
1883 * thread / process pending signal.
1886 ksignal(curproc, info.si_signo);
1888 sysmsg->sysmsg_result = info.si_signo;
1897 sys_sigwaitinfo(struct sysmsg *sysmsg, const struct sigwaitinfo_args *uap)
1903 error = copyin(uap->set, &set, sizeof(set));
1906 error = kern_sigtimedwait(set, &info, NULL);
1910 error = copyout(&info, uap->info, sizeof(info));
1911 /* Repost if we got an error. */
1915 * This could transform a thread-specific signal to another
1916 * thread / process pending signal.
1919 ksignal(curproc, info.si_signo);
1921 sysmsg->sysmsg_result = info.si_signo;
1927 * If the current process has received a signal that would interrupt a
1928 * system call, return EINTR or ERESTART as appropriate.
1931 iscaught(struct lwp *lp)
1933 struct proc *p = lp->lwp_proc;
1937 if ((sig = CURSIG(lp)) != 0) {
1938 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1943 return(EWOULDBLOCK);
1947 * If the current lwp/proc has received a signal (should be caught or cause
1948 * termination, should interrupt current syscall), return the signal number.
1949 * Stop signals with default action are processed immediately, then cleared;
1950 * they aren't returned. This is checked after each entry to the system for
1951 * a syscall or trap (though this can usually be done without calling issignal
1952 * by checking the pending signal masks in the CURSIG macro).
1954 * This routine is called via CURSIG/__cursig. We will acquire and release
1955 * p->p_token but if the caller needs to interlock the test the caller must
1956 * also hold p->p_token.
1958 * while (sig = CURSIG(curproc))
1962 issignal(struct lwp *lp, int maytrace, int *ptokp)
1964 struct proc *p = lp->lwp_proc;
1970 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG);
1975 * NOTE: Do not tstop here. Issue the proc_stop()
1976 * so other parties see that we know we need
1977 * to stop, but don't block here. Locks might
1980 * XXX If this process is supposed to stop, stop this thread.
1984 if (STOPLWP(p, lp)) {
1985 lwkt_gettoken(&p->p_token);
1987 lwkt_reltoken(&p->p_token);
1992 * Quick check without token
1994 mask = lwp_sigpend(lp);
1995 SIGSETNAND(mask, lp->lwp_sigmask);
1996 if (p->p_flags & P_PPWAIT)
1997 SIG_STOPSIGMASK(mask);
1998 SIG_CONDBLOCKALLSIGS(mask, lp);
2000 if (SIGISEMPTY(mask)) /* no signal to send */
2004 * If the signal is a member of the process signal set
2005 * we need p_token (even if it is also a member of the
2008 sig = sig_ffs(&mask);
2009 if (SIGISMEMBER(p->p_siglist, sig)) {
2011 * Recheck with token
2014 lwkt_gettoken(&p->p_token);
2016 mask = lwp_sigpend(lp);
2017 SIGSETNAND(mask, lp->lwp_sigmask);
2018 if (p->p_flags & P_PPWAIT)
2019 SIG_STOPSIGMASK(mask);
2020 if (SIGISEMPTY(mask)) { /* no signal to send */
2021 /* haveptok is TRUE */
2022 lwkt_reltoken(&p->p_token);
2025 sig = sig_ffs(&mask);
2028 STOPEVENT(p, S_SIG, sig);
2031 * We should see pending but ignored signals
2032 * only if P_TRACED was on when they were posted.
2034 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
2035 spin_lock(&lp->lwp_spin);
2036 lwp_delsig(lp, sig, haveptok);
2037 spin_unlock(&lp->lwp_spin);
2039 lwkt_reltoken(&p->p_token);
2043 (p->p_flags & P_TRACED) &&
2044 (p->p_flags & P_PPWAIT) == 0) {
2046 * If traced, always stop, and stay stopped until
2047 * released by the parent.
2049 * NOTE: SSTOP may get cleared during the loop, but
2050 * we do not re-notify the parent if we have
2051 * to loop several times waiting for the parent
2052 * to let us continue. XXX not sure if this is
2055 * NOTE: Do not tstop here. Issue the proc_stop()
2056 * so other parties see that we know we need
2057 * to stop, but don't block here. Locks might
2060 if (haveptok == 0) {
2061 lwkt_gettoken(&p->p_token);
2065 proc_stop(p, SSTOP);
2068 * Normally we don't stop until we return to userland, but
2069 * make an exception when tracing and 'maytrace' is asserted.
2071 if (p->p_flags & P_TRACED)
2075 * If parent wants us to take the signal,
2076 * then it will leave it in p->p_xstat;
2077 * otherwise we just look for signals again.
2079 spin_lock(&lp->lwp_spin);
2080 lwp_delsig(lp, sig, 1); /* clear old signal */
2081 spin_unlock(&lp->lwp_spin);
2084 /* haveptok is TRUE */
2085 lwkt_reltoken(&p->p_token);
2090 * Put the new signal into p_siglist. If the
2091 * signal is being masked, look for other signals.
2093 * XXX lwp might need a call to ksignal()
2095 SIGADDSET_ATOMIC(p->p_siglist, sig);
2096 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
2097 /* haveptok is TRUE */
2098 lwkt_reltoken(&p->p_token);
2103 * If the traced bit got turned off, go back up
2104 * to the top to rescan signals. This ensures
2105 * that p_sig* and ps_sigact are consistent.
2107 if ((p->p_flags & P_TRACED) == 0) {
2108 /* haveptok is TRUE */
2109 lwkt_reltoken(&p->p_token);
2115 * p_token may be held here
2117 prop = sigprop(sig);
2120 * Decide whether the signal should be returned.
2121 * Return the signal's number, or fall through
2122 * to clear it from the pending mask.
2124 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
2125 case (intptr_t)SIG_DFL:
2127 * Don't take default actions on system processes.
2129 if (p->p_pid <= 1) {
2132 * Are you sure you want to ignore SIGSEGV
2135 kprintf("Process (pid %lu) got signal %d\n",
2136 (u_long)p->p_pid, sig);
2138 break; /* == ignore */
2142 * Handle the in-kernel checkpoint action
2144 if (prop & SA_CKPT) {
2145 if (haveptok == 0) {
2146 lwkt_gettoken(&p->p_token);
2149 checkpoint_signal_handler(lp);
2154 * If there is a pending stop signal to process
2155 * with default action, stop here,
2156 * then clear the signal. However,
2157 * if process is member of an orphaned
2158 * process group, ignore tty stop signals.
2160 if (prop & SA_STOP) {
2161 if (haveptok == 0) {
2162 lwkt_gettoken(&p->p_token);
2165 if (p->p_flags & P_TRACED ||
2166 (p->p_pgrp->pg_jobc == 0 &&
2168 break; /* == ignore */
2169 if ((p->p_flags & P_WEXIT) == 0) {
2171 * NOTE: We do not block here. Issue
2172 * stopthe stop so other parties
2173 * see that we know we need to
2174 * stop. Locks might be held.
2177 proc_stop(p, SSTOP);
2184 } else if (prop & SA_IGNORE) {
2186 * Except for SIGCONT, shouldn't get here.
2187 * Default action is to ignore; drop it.
2189 break; /* == ignore */
2194 lwkt_reltoken(&p->p_token);
2200 case (intptr_t)SIG_IGN:
2202 * Masking above should prevent us ever trying
2203 * to take action on an ignored signal other
2204 * than SIGCONT, unless process is traced.
2206 if ((prop & SA_CONT) == 0 &&
2207 (p->p_flags & P_TRACED) == 0)
2208 kprintf("issignal\n");
2209 break; /* == ignore */
2213 * This signal has an action, let
2214 * postsig() process it.
2219 lwkt_reltoken(&p->p_token);
2222 spin_lock(&lp->lwp_spin);
2223 lwp_delsig(lp, sig, haveptok); /* take the signal! */
2224 spin_unlock(&lp->lwp_spin);
2227 lwkt_reltoken(&p->p_token);
2233 * Take the action for the specified signal from the current set of
2236 * haveptok indicates whether the caller is holding p->p_token. If the
2237 * caller is, we are responsible for releasing it.
2239 * This routine can only be called from the top-level trap from usermode.
2240 * It is expecting to be able to modify the top-level stack frame.
2243 postsig(int sig, int haveptok)
2245 struct lwp *lp = curthread->td_lwp;
2246 struct proc *p = lp->lwp_proc;
2247 struct sigacts *ps = p->p_sigacts;
2249 sigset_t returnmask;
2252 KASSERT(sig != 0, ("postsig"));
2255 * If we are a virtual kernel running an emulated user process
2256 * context, switch back to the virtual kernel context before
2257 * trying to post the signal.
2259 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
2260 struct trapframe *tf = lp->lwp_md.md_regs;
2262 vkernel_trap(lp, tf);
2265 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
2267 spin_lock(&lp->lwp_spin);
2268 lwp_delsig(lp, sig, haveptok);
2269 spin_unlock(&lp->lwp_spin);
2270 action = ps->ps_sigact[_SIG_IDX(sig)];
2272 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
2273 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ?
2274 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
2277 * We don't need p_token after this point.
2280 lwkt_reltoken(&p->p_token);
2282 STOPEVENT(p, S_SIG, sig);
2284 if (action == SIG_DFL) {
2286 * Default action, where the default is to kill
2287 * the process. (Other cases were ignored above.)
2293 * If we get here, the signal must be caught.
2295 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
2296 ("postsig action"));
2299 * Reset the signal handler if asked to
2301 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
2303 * See kern_sigaction() for origin of this code.
2305 SIGDELSET(p->p_sigcatch, sig);
2306 if (sig != SIGCONT &&
2307 sigprop(sig) & SA_IGNORE)
2308 SIGADDSET(p->p_sigignore, sig);
2309 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
2313 * Set the signal mask and calculate the mask to restore
2314 * when the signal function returns.
2316 * Special case: user has done a sigsuspend. Here the
2317 * current mask is not of interest, but rather the
2318 * mask from before the sigsuspend is what we want
2319 * restored after the signal processing is completed.
2321 if (lp->lwp_flags & LWP_OLDMASK) {
2322 returnmask = lp->lwp_oldsigmask;
2323 lp->lwp_flags &= ~LWP_OLDMASK;
2325 returnmask = lp->lwp_sigmask;
2328 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
2329 if (!SIGISMEMBER(ps->ps_signodefer, sig))
2330 SIGADDSET(lp->lwp_sigmask, sig);
2332 lp->lwp_ru.ru_nsignals++;
2333 if (lp->lwp_sig != sig) {
2336 code = lp->lwp_code;
2340 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
2345 * Kill the current process for stated reason.
2348 killproc(struct proc *p, char *why)
2350 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
2351 p->p_pid, p->p_comm,
2352 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
2353 ksignal(p, SIGKILL);
2357 * Force the current process to exit with the specified signal, dumping core
2358 * if appropriate. We bypass the normal tests for masked and caught signals,
2359 * allowing unrecoverable failures to terminate the process without changing
2360 * signal state. Mark the accounting record with the signal termination.
2361 * If dumping core, save the signal number for the debugger. Calls exit and
2364 * This routine does not return.
2367 sigexit(struct lwp *lp, int sig)
2369 struct proc *p = lp->lwp_proc;
2371 lwkt_gettoken(&p->p_token);
2372 p->p_acflag |= AXSIG;
2373 if (sigprop(sig) & SA_CORE) {
2377 * All threads must be stopped before we can safely coredump.
2378 * Stop threads using SCORE, which cannot be overridden.
2380 if (p->p_stat != SCORE) {
2381 proc_stop(p, SCORE);
2384 if (coredump(lp, sig) == 0)
2390 * Log signals which would cause core dumps
2391 * (Log as LOG_INFO to appease those who don't want
2393 * XXX : Todo, as well as euid, write out ruid too
2395 if (kern_logsigexit) {
2397 "pid %d (%s), uid %d: exited on signal %d%s\n",
2398 p->p_pid, p->p_comm,
2399 p->p_ucred ? p->p_ucred->cr_uid : -1,
2401 sig & WCOREFLAG ? " (core dumped)" : "");
2402 if (kern_logsigexit > 1)
2403 kprintf("DEBUG - waiting on kern.logsigexit\n");
2404 while (kern_logsigexit > 1) {
2405 tsleep(&kern_logsigexit, 0, "DEBUG", hz);
2409 lwkt_reltoken(&p->p_token);
2410 exit1(W_EXITCODE(0, sig));
2414 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
2415 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
2416 sizeof(corefilename), "process corefile name format string");
2419 * expand_name(name, uid, pid)
2420 * Expand the name described in corefilename, using name, uid, and pid.
2421 * corefilename is a kprintf-like string, with three format specifiers:
2422 * %N name of process ("name")
2423 * %P process id (pid)
2425 * For example, "%N.core" is the default; they can be disabled completely
2426 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
2427 * This is controlled by the sysctl variable kern.corefile (see above).
2431 expand_name(const char *name, uid_t uid, pid_t pid)
2434 char buf[11]; /* Buffer for pid/uid -- max 4B */
2436 char *format = corefilename;
2439 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
2442 namelen = strlen(name);
2443 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
2445 switch (format[i]) {
2446 case '%': /* Format character */
2448 switch (format[i]) {
2452 case 'N': /* process name */
2453 if ((n + namelen) > MAXPATHLEN) {
2454 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2455 pid, name, uid, temp, name);
2456 kfree(temp, M_TEMP);
2459 memcpy(temp+n, name, namelen);
2462 case 'P': /* process id */
2463 l = ksprintf(buf, "%u", pid);
2464 if ((n + l) > MAXPATHLEN) {
2465 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2466 pid, name, uid, temp, name);
2467 kfree(temp, M_TEMP);
2470 memcpy(temp+n, buf, l);
2473 case 'U': /* user id */
2474 l = ksprintf(buf, "%u", uid);
2475 if ((n + l) > MAXPATHLEN) {
2476 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2477 pid, name, uid, temp, name);
2478 kfree(temp, M_TEMP);
2481 memcpy(temp+n, buf, l);
2485 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
2489 temp[n++] = format[i];
2497 * Dump a process' core. The main routine does some
2498 * policy checking, and creates the name of the coredump;
2499 * then it passes on a vnode and a size limit to the process-specific
2500 * coredump routine if there is one; if there _is not_ one, it returns
2501 * ENOSYS; otherwise it returns the error from the process-specific routine.
2503 * The parameter `lp' is the lwp which triggered the coredump.
2507 coredump(struct lwp *lp, int sig)
2509 struct proc *p = lp->lwp_proc;
2511 struct ucred *cred = p->p_ucred;
2513 struct nlookupdata nd;
2516 char *name; /* name of corefile */
2519 STOPEVENT(p, S_CORE, 0);
2521 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0)
2525 * Note that the bulk of limit checking is done after
2526 * the corefile is created. The exception is if the limit
2527 * for corefiles is 0, in which case we don't bother
2528 * creating the corefile at all. This layout means that
2529 * a corefile is truncated instead of not being created,
2530 * if it is larger than the limit.
2532 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
2536 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
2539 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
2541 error = vn_open(&nd, NULL,
2542 O_CREAT | FWRITE | O_NOFOLLOW,
2544 kfree(name, M_TEMP);
2550 nd.nl_open_vp = NULL;
2554 lf.l_whence = SEEK_SET;
2557 lf.l_type = F_WRLCK;
2558 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2562 /* Don't dump to non-regular files or files with links. */
2563 if (vp->v_type != VREG ||
2564 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2569 /* Don't dump to files current user does not own */
2570 if (vattr.va_uid != p->p_ucred->cr_uid) {
2576 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2578 VOP_SETATTR(vp, &vattr, cred);
2579 p->p_acflag |= ACORE;
2582 error = p->p_sysent->sv_coredump ?
2583 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2586 lf.l_type = F_UNLCK;
2587 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2589 error1 = vn_close(vp, FWRITE, NULL);
2596 * Nonexistent system call-- signal process (may want to handle it).
2597 * Flag error in case process won't see signal immediately (blocked or ignored).
2603 sys_nosys(struct sysmsg *sysmsg, const struct nosys_args *args)
2605 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2610 * Send a SIGIO or SIGURG signal to a process or process group using
2611 * stored credentials rather than those of the current process.
2614 pgsigio(struct sigio *sigio, int sig, int checkctty)
2619 if (sigio->sio_pgid > 0) {
2620 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2622 ksignal(sigio->sio_proc, sig);
2623 } else if (sigio->sio_pgid < 0) {
2625 struct pgrp *pg = sigio->sio_pgrp;
2628 * Must interlock all signals against fork
2631 lockmgr(&pg->pg_lock, LK_EXCLUSIVE);
2632 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
2633 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2634 (checkctty == 0 || (p->p_flags & P_CONTROLT)))
2637 lockmgr(&pg->pg_lock, LK_RELEASE);
2643 filt_sigattach(struct knote *kn)
2645 struct proc *p = curproc;
2647 kn->kn_ptr.p_proc = p;
2648 kn->kn_flags |= EV_CLEAR; /* automatically set */
2650 /* XXX lock the proc here while adding to the list? */
2651 knote_insert(&p->p_klist, kn);
2657 filt_sigdetach(struct knote *kn)
2659 struct proc *p = kn->kn_ptr.p_proc;
2661 knote_remove(&p->p_klist, kn);
2665 * signal knotes are shared with proc knotes, so we apply a mask to
2666 * the hint in order to differentiate them from process hints. This
2667 * could be avoided by using a signal-specific knote list, but probably
2668 * isn't worth the trouble.
2671 filt_signal(struct knote *kn, long hint)
2673 if (hint & NOTE_SIGNAL) {
2674 hint &= ~NOTE_SIGNAL;
2676 if (kn->kn_id == hint)
2679 return (kn->kn_data != 0);