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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 $
42 #include "opt_ktrace.h"
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/sysproto.h>
48 #include <sys/signalvar.h>
49 #include <sys/resourcevar.h>
50 #include <sys/vnode.h>
51 #include <sys/event.h>
53 #include <sys/nlookup.h>
54 #include <sys/pioctl.h>
55 #include <sys/systm.h>
57 #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/interrupt.h>
67 #include <sys/unistd.h>
68 #include <sys/kern_syscall.h>
69 #include <sys/vkernel.h>
71 #include <sys/signal2.h>
72 #include <sys/thread2.h>
74 #include <machine/cpu.h>
75 #include <machine/smp.h>
77 static int coredump(struct lwp *, int);
78 static char *expand_name(const char *, uid_t, pid_t);
79 static int dokillpg(int sig, int pgid, int all);
80 static int sig_ffs(sigset_t *set);
81 static int sigprop(int sig);
82 static void lwp_signotify(struct lwp *lp);
84 static void signotify_remote(void *arg);
86 static int kern_sigtimedwait(sigset_t set, siginfo_t *info,
87 struct timespec *timeout);
89 static int filt_sigattach(struct knote *kn);
90 static void filt_sigdetach(struct knote *kn);
91 static int filt_signal(struct knote *kn, long hint);
93 struct filterops sig_filtops =
94 { 0, filt_sigattach, filt_sigdetach, filt_signal };
96 static int kern_logsigexit = 1;
97 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
99 "Log processes quitting on abnormal signals to syslog(3)");
102 * Can process p, with pcred pc, send the signal sig to process q?
104 #define CANSIGNAL(q, sig) \
105 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \
106 ((sig) == SIGCONT && (q)->p_session == curproc->p_session))
109 * Policy -- Can real uid ruid with ucred uc send a signal to process q?
111 #define CANSIGIO(ruid, uc, q) \
112 ((uc)->cr_uid == 0 || \
113 (ruid) == (q)->p_ucred->cr_ruid || \
114 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \
115 (ruid) == (q)->p_ucred->cr_uid || \
116 (uc)->cr_uid == (q)->p_ucred->cr_uid)
119 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
120 &sugid_coredump, 0, "Enable coredumping set user/group ID processes");
122 static int do_coredump = 1;
123 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
124 &do_coredump, 0, "Enable/Disable coredumps");
127 * Signal properties and actions.
128 * The array below categorizes the signals and their default actions
129 * according to the following properties:
131 #define SA_KILL 0x01 /* terminates process by default */
132 #define SA_CORE 0x02 /* ditto and coredumps */
133 #define SA_STOP 0x04 /* suspend process */
134 #define SA_TTYSTOP 0x08 /* ditto, from tty */
135 #define SA_IGNORE 0x10 /* ignore by default */
136 #define SA_CONT 0x20 /* continue if suspended */
137 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
138 #define SA_CKPT 0x80 /* checkpoint process */
141 static int sigproptbl[NSIG] = {
142 SA_KILL, /* SIGHUP */
143 SA_KILL, /* SIGINT */
144 SA_KILL|SA_CORE, /* SIGQUIT */
145 SA_KILL|SA_CORE, /* SIGILL */
146 SA_KILL|SA_CORE, /* SIGTRAP */
147 SA_KILL|SA_CORE, /* SIGABRT */
148 SA_KILL|SA_CORE, /* SIGEMT */
149 SA_KILL|SA_CORE, /* SIGFPE */
150 SA_KILL, /* SIGKILL */
151 SA_KILL|SA_CORE, /* SIGBUS */
152 SA_KILL|SA_CORE, /* SIGSEGV */
153 SA_KILL|SA_CORE, /* SIGSYS */
154 SA_KILL, /* SIGPIPE */
155 SA_KILL, /* SIGALRM */
156 SA_KILL, /* SIGTERM */
157 SA_IGNORE, /* SIGURG */
158 SA_STOP, /* SIGSTOP */
159 SA_STOP|SA_TTYSTOP, /* SIGTSTP */
160 SA_IGNORE|SA_CONT, /* SIGCONT */
161 SA_IGNORE, /* SIGCHLD */
162 SA_STOP|SA_TTYSTOP, /* SIGTTIN */
163 SA_STOP|SA_TTYSTOP, /* SIGTTOU */
164 SA_IGNORE, /* SIGIO */
165 SA_KILL, /* SIGXCPU */
166 SA_KILL, /* SIGXFSZ */
167 SA_KILL, /* SIGVTALRM */
168 SA_KILL, /* SIGPROF */
169 SA_IGNORE, /* SIGWINCH */
170 SA_IGNORE, /* SIGINFO */
171 SA_KILL, /* SIGUSR1 */
172 SA_KILL, /* SIGUSR2 */
173 SA_IGNORE, /* SIGTHR */
174 SA_CKPT, /* SIGCKPT */
175 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */
213 if (sig > 0 && sig < NSIG)
214 return (sigproptbl[_SIG_IDX(sig)]);
219 sig_ffs(sigset_t *set)
223 for (i = 0; i < _SIG_WORDS; i++)
225 return (ffs(set->__bits[i]) + (i * 32));
233 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact)
235 struct thread *td = curthread;
236 struct proc *p = td->td_proc;
238 struct sigacts *ps = p->p_sigacts;
240 if (sig <= 0 || sig > _SIG_MAXSIG)
243 lwkt_gettoken(&p->p_token);
246 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
247 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
249 if (SIGISMEMBER(ps->ps_sigonstack, sig))
250 oact->sa_flags |= SA_ONSTACK;
251 if (!SIGISMEMBER(ps->ps_sigintr, sig))
252 oact->sa_flags |= SA_RESTART;
253 if (SIGISMEMBER(ps->ps_sigreset, sig))
254 oact->sa_flags |= SA_RESETHAND;
255 if (SIGISMEMBER(ps->ps_signodefer, sig))
256 oact->sa_flags |= SA_NODEFER;
257 if (SIGISMEMBER(ps->ps_siginfo, sig))
258 oact->sa_flags |= SA_SIGINFO;
259 if (SIGISMEMBER(ps->ps_sigmailbox, sig))
260 oact->sa_flags |= SA_MAILBOX;
261 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP)
262 oact->sa_flags |= SA_NOCLDSTOP;
263 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT)
264 oact->sa_flags |= SA_NOCLDWAIT;
268 * Check for invalid requests. KILL and STOP cannot be
271 if (sig == SIGKILL || sig == SIGSTOP) {
272 if (act->sa_handler != SIG_DFL) {
273 lwkt_reltoken(&p->p_token);
277 /* (not needed, SIG_DFL forces action to occur) */
278 if (act->sa_flags & SA_MAILBOX) {
279 lwkt_reltoken(&p->p_token);
286 * Change setting atomically.
290 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
291 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
292 if (act->sa_flags & SA_SIGINFO) {
293 ps->ps_sigact[_SIG_IDX(sig)] =
294 (__sighandler_t *)act->sa_sigaction;
295 SIGADDSET(ps->ps_siginfo, sig);
297 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
298 SIGDELSET(ps->ps_siginfo, sig);
300 if (!(act->sa_flags & SA_RESTART))
301 SIGADDSET(ps->ps_sigintr, sig);
303 SIGDELSET(ps->ps_sigintr, sig);
304 if (act->sa_flags & SA_ONSTACK)
305 SIGADDSET(ps->ps_sigonstack, sig);
307 SIGDELSET(ps->ps_sigonstack, sig);
308 if (act->sa_flags & SA_RESETHAND)
309 SIGADDSET(ps->ps_sigreset, sig);
311 SIGDELSET(ps->ps_sigreset, sig);
312 if (act->sa_flags & SA_NODEFER)
313 SIGADDSET(ps->ps_signodefer, sig);
315 SIGDELSET(ps->ps_signodefer, sig);
316 if (act->sa_flags & SA_MAILBOX)
317 SIGADDSET(ps->ps_sigmailbox, sig);
319 SIGDELSET(ps->ps_sigmailbox, sig);
320 if (sig == SIGCHLD) {
321 if (act->sa_flags & SA_NOCLDSTOP)
322 p->p_sigacts->ps_flag |= PS_NOCLDSTOP;
324 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP;
325 if (act->sa_flags & SA_NOCLDWAIT) {
327 * Paranoia: since SA_NOCLDWAIT is implemented
328 * by reparenting the dying child to PID 1 (and
329 * trust it to reap the zombie), PID 1 itself
330 * is forbidden to set SA_NOCLDWAIT.
333 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
335 p->p_sigacts->ps_flag |= PS_NOCLDWAIT;
337 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
341 * Set bit in p_sigignore for signals that are set to SIG_IGN,
342 * and for signals set to SIG_DFL where the default is to
343 * ignore. However, don't put SIGCONT in p_sigignore, as we
344 * have to restart the process.
346 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
347 (sigprop(sig) & SA_IGNORE &&
348 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
349 /* never to be seen again */
350 SIGDELSET(p->p_siglist, sig);
352 * Remove the signal also from the thread lists.
354 FOREACH_LWP_IN_PROC(lp, p) {
355 SIGDELSET(lp->lwp_siglist, sig);
357 if (sig != SIGCONT) {
358 /* easier in ksignal */
359 SIGADDSET(p->p_sigignore, sig);
361 SIGDELSET(p->p_sigcatch, sig);
363 SIGDELSET(p->p_sigignore, sig);
364 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
365 SIGDELSET(p->p_sigcatch, sig);
367 SIGADDSET(p->p_sigcatch, sig);
372 lwkt_reltoken(&p->p_token);
377 sys_sigaction(struct sigaction_args *uap)
379 struct sigaction act, oact;
380 struct sigaction *actp, *oactp;
383 actp = (uap->act != NULL) ? &act : NULL;
384 oactp = (uap->oact != NULL) ? &oact : NULL;
386 error = copyin(uap->act, actp, sizeof(act));
390 error = kern_sigaction(uap->sig, actp, oactp);
391 if (oactp && !error) {
392 error = copyout(oactp, uap->oact, sizeof(oact));
398 * Initialize signal state for process 0;
399 * set to ignore signals that are ignored by default.
402 siginit(struct proc *p)
406 for (i = 1; i <= NSIG; i++)
407 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
408 SIGADDSET(p->p_sigignore, i);
412 * Reset signals for an exec of the specified process.
415 execsigs(struct proc *p)
417 struct sigacts *ps = p->p_sigacts;
421 lp = ONLY_LWP_IN_PROC(p);
424 * Reset caught signals. Held signals remain held
425 * through p_sigmask (unless they were caught,
426 * and are now ignored by default).
428 while (SIGNOTEMPTY(p->p_sigcatch)) {
429 sig = sig_ffs(&p->p_sigcatch);
430 SIGDELSET(p->p_sigcatch, sig);
431 if (sigprop(sig) & SA_IGNORE) {
433 SIGADDSET(p->p_sigignore, sig);
434 SIGDELSET(p->p_siglist, sig);
435 SIGDELSET(lp->lwp_siglist, sig);
437 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
441 * Reset stack state to the user stack.
442 * Clear set of signals caught on the signal stack.
444 lp->lwp_sigstk.ss_flags = SS_DISABLE;
445 lp->lwp_sigstk.ss_size = 0;
446 lp->lwp_sigstk.ss_sp = 0;
447 lp->lwp_flag &= ~LWP_ALTSTACK;
449 * Reset no zombies if child dies flag as Solaris does.
451 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
455 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
457 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
461 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
463 struct thread *td = curthread;
464 struct lwp *lp = td->td_lwp;
465 struct proc *p = td->td_proc;
468 lwkt_gettoken(&p->p_token);
471 *oset = lp->lwp_sigmask;
478 SIGSETOR(lp->lwp_sigmask, *set);
481 SIGSETNAND(lp->lwp_sigmask, *set);
485 lp->lwp_sigmask = *set;
493 lwkt_reltoken(&p->p_token);
504 sys_sigprocmask(struct sigprocmask_args *uap)
507 sigset_t *setp, *osetp;
510 setp = (uap->set != NULL) ? &set : NULL;
511 osetp = (uap->oset != NULL) ? &oset : NULL;
513 error = copyin(uap->set, setp, sizeof(set));
517 error = kern_sigprocmask(uap->how, setp, osetp);
518 if (osetp && !error) {
519 error = copyout(osetp, uap->oset, sizeof(oset));
528 kern_sigpending(struct __sigset *set)
530 struct lwp *lp = curthread->td_lwp;
532 *set = lwp_sigpend(lp);
541 sys_sigpending(struct sigpending_args *uap)
546 error = kern_sigpending(&set);
549 error = copyout(&set, uap->set, sizeof(set));
554 * Suspend process until signal, providing mask to be set
560 kern_sigsuspend(struct __sigset *set)
562 struct thread *td = curthread;
563 struct lwp *lp = td->td_lwp;
564 struct proc *p = td->td_proc;
565 struct sigacts *ps = p->p_sigacts;
568 * When returning from sigsuspend, we want
569 * the old mask to be restored after the
570 * signal handler has finished. Thus, we
571 * save it here and mark the sigacts structure
574 lp->lwp_oldsigmask = lp->lwp_sigmask;
575 lp->lwp_flag |= LWP_OLDMASK;
578 lp->lwp_sigmask = *set;
579 while (tsleep(ps, PCATCH, "pause", 0) == 0)
581 /* always return EINTR rather than ERESTART... */
586 * Note nonstandard calling convention: libc stub passes mask, not
587 * pointer, to save a copyin.
592 sys_sigsuspend(struct sigsuspend_args *uap)
597 error = copyin(uap->sigmask, &mask, sizeof(mask));
601 error = kern_sigsuspend(&mask);
610 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss)
612 struct thread *td = curthread;
613 struct lwp *lp = td->td_lwp;
614 struct proc *p = td->td_proc;
616 if ((lp->lwp_flag & LWP_ALTSTACK) == 0)
617 lp->lwp_sigstk.ss_flags |= SS_DISABLE;
620 *oss = lp->lwp_sigstk;
623 if (ss->ss_flags & SS_DISABLE) {
624 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK)
626 lp->lwp_flag &= ~LWP_ALTSTACK;
627 lp->lwp_sigstk.ss_flags = ss->ss_flags;
629 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
631 lp->lwp_flag |= LWP_ALTSTACK;
632 lp->lwp_sigstk = *ss;
643 sys_sigaltstack(struct sigaltstack_args *uap)
649 error = copyin(uap->ss, &ss, sizeof(ss));
654 error = kern_sigaltstack(uap->ss ? &ss : NULL,
655 uap->oss ? &oss : NULL);
657 if (error == 0 && uap->oss)
658 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
663 * Common code for kill process group/broadcast kill.
664 * cp is calling process.
671 static int killpg_all_callback(struct proc *p, void *data);
674 dokillpg(int sig, int pgid, int all)
676 struct killpg_info info;
677 struct proc *cp = curproc;
688 allproc_scan(killpg_all_callback, &info);
692 * zero pgid means send to my process group.
703 * Must interlock all signals against fork
705 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
706 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
708 p->p_stat == SZOMB ||
709 (p->p_flag & P_SYSTEM) ||
710 !CANSIGNAL(p, sig)) {
717 lockmgr(&pgrp->pg_lock, LK_RELEASE);
720 return (info.nfound ? 0 : ESRCH);
724 killpg_all_callback(struct proc *p, void *data)
726 struct killpg_info *info = data;
728 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) ||
729 p == curproc || !CANSIGNAL(p, info->sig)) {
734 ksignal(p, info->sig);
739 * Send a general signal to a process or LWPs within that process. Note
740 * that new signals cannot be sent if a process is exiting.
745 kern_kill(int sig, pid_t pid, lwpid_t tid)
749 if ((u_int)sig > _SIG_MAXSIG)
752 lwkt_gettoken(&proc_token);
756 struct lwp *lp = NULL;
758 /* kill single process */
759 if ((p = pfind(pid)) == NULL) {
760 lwkt_reltoken(&proc_token);
763 lwkt_gettoken(&p->p_token);
764 if (!CANSIGNAL(p, sig)) {
765 lwkt_reltoken(&p->p_token);
767 lwkt_reltoken(&proc_token);
772 * NOP if the process is exiting. Note that lwpsignal() is
773 * called directly with P_WEXIT set to kill individual LWPs
774 * during exit, which is allowed.
776 if (p->p_flag & P_WEXIT) {
777 lwkt_reltoken(&p->p_token);
779 lwkt_reltoken(&proc_token);
783 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid);
785 lwkt_reltoken(&p->p_token);
787 lwkt_reltoken(&proc_token);
792 lwpsignal(p, lp, sig);
793 lwkt_reltoken(&p->p_token);
795 lwkt_reltoken(&proc_token);
800 * If we come here, pid is a special broadcast pid.
801 * This doesn't mix with a tid.
804 lwkt_reltoken(&proc_token);
808 case -1: /* broadcast signal */
809 t = (dokillpg(sig, 0, 1));
811 case 0: /* signal own process group */
812 t = (dokillpg(sig, 0, 0));
814 default: /* negative explicit process group */
815 t = (dokillpg(sig, -pid, 0));
818 lwkt_reltoken(&proc_token);
823 sys_kill(struct kill_args *uap)
827 error = kern_kill(uap->signum, uap->pid, -1);
832 sys_lwp_kill(struct lwp_kill_args *uap)
835 pid_t pid = uap->pid;
838 * A tid is mandatory for lwp_kill(), otherwise
839 * you could simply use kill().
845 * To save on a getpid() function call for intra-process
846 * signals, pid == -1 means current process.
849 pid = curproc->p_pid;
851 error = kern_kill(uap->signum, pid, uap->tid);
856 * Send a signal to a process group.
859 gsignal(int pgid, int sig)
863 if (pgid && (pgrp = pgfind(pgid)))
864 pgsignal(pgrp, sig, 0);
868 * Send a signal to a process group. If checktty is 1,
869 * limit to members which have a controlling terminal.
871 * pg_lock interlocks against a fork that might be in progress, to
872 * ensure that the new child process picks up the signal.
875 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
880 * Must interlock all signals against fork
884 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
885 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
886 if (checkctty == 0 || p->p_flag & P_CONTROLT)
889 lockmgr(&pgrp->pg_lock, LK_RELEASE);
895 * Send a signal caused by a trap to the current lwp. If it will be caught
896 * immediately, deliver it with correct code. Otherwise, post it normally.
898 * These signals may ONLY be delivered to the specified lwp and may never
899 * be delivered to the process generically.
902 trapsignal(struct lwp *lp, int sig, u_long code)
904 struct proc *p = lp->lwp_proc;
905 struct sigacts *ps = p->p_sigacts;
908 * If we are a virtual kernel running an emulated user process
909 * context, switch back to the virtual kernel context before
910 * trying to post the signal.
912 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
913 struct trapframe *tf = lp->lwp_md.md_regs;
915 vkernel_trap(lp, tf);
919 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
920 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
921 lp->lwp_ru.ru_nsignals++;
923 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
924 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)],
925 &lp->lwp_sigmask, code);
927 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
928 &lp->lwp_sigmask, code);
929 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
930 if (!SIGISMEMBER(ps->ps_signodefer, sig))
931 SIGADDSET(lp->lwp_sigmask, sig);
932 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
934 * See kern_sigaction() for origin of this code.
936 SIGDELSET(p->p_sigcatch, sig);
937 if (sig != SIGCONT &&
938 sigprop(sig) & SA_IGNORE)
939 SIGADDSET(p->p_sigignore, sig);
940 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
943 lp->lwp_code = code; /* XXX for core dump/debugger */
944 lp->lwp_sig = sig; /* XXX to verify code */
945 lwpsignal(p, lp, sig);
950 * Find a suitable lwp to deliver the signal to. Returns NULL if all
951 * lwps hold the signal blocked.
953 * Caller must hold p->p_token.
956 find_lwp_for_signal(struct proc *p, int sig)
959 struct lwp *run, *sleep, *stop;
962 * If the running/preempted thread belongs to the proc to which
963 * the signal is being delivered and this thread does not block
964 * the signal, then we can avoid a context switch by delivering
965 * the signal to this thread, because it will return to userland
968 lp = lwkt_preempted_proc();
969 if (lp != NULL && lp->lwp_proc == p &&
970 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
974 run = sleep = stop = NULL;
975 FOREACH_LWP_IN_PROC(lp, p) {
977 * If the signal is being blocked by the lwp, then this
978 * lwp is not eligible for receiving the signal.
980 if (SIGISMEMBER(lp->lwp_sigmask, sig))
983 switch (lp->lwp_stat) {
993 if (lp->lwp_flag & LWP_SINTR)
1001 else if (sleep != NULL)
1008 * Send the signal to the process. If the signal has an action, the action
1009 * is usually performed by the target process rather than the caller; we add
1010 * the signal to the set of pending signals for the process.
1013 * o When a stop signal is sent to a sleeping process that takes the
1014 * default action, the process is stopped without awakening it.
1015 * o SIGCONT restarts stopped processes (or puts them back to sleep)
1016 * regardless of the signal action (eg, blocked or ignored).
1018 * Other ignored signals are discarded immediately.
1020 * If the caller wishes to call this function from a hard code section the
1021 * caller must already hold p->p_token (see kern_clock.c).
1026 ksignal(struct proc *p, int sig)
1028 lwpsignal(p, NULL, sig);
1032 * The core for ksignal. lp may be NULL, then a suitable thread
1033 * will be chosen. If not, lp MUST be a member of p.
1035 * If the caller wishes to call this function from a hard code section the
1036 * caller must already hold p->p_token.
1041 lwpsignal(struct proc *p, struct lwp *lp, int sig)
1046 if (sig > _SIG_MAXSIG || sig <= 0) {
1047 kprintf("lwpsignal: signal %d\n", sig);
1048 panic("lwpsignal signal number");
1051 KKASSERT(lp == NULL || lp->lwp_proc == p);
1054 lwkt_gettoken(&p->p_token);
1056 prop = sigprop(sig);
1059 * If proc is traced, always give parent a chance;
1060 * if signal event is tracked by procfs, give *that*
1061 * a chance, as well.
1063 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
1067 * Do not try to deliver signals to an exiting lwp. Note
1068 * that we must still deliver the signal if P_WEXIT is set
1069 * in the process flags.
1071 if (lp && (lp->lwp_flag & LWP_WEXIT)) {
1072 lwkt_reltoken(&p->p_token);
1078 * If the signal is being ignored, then we forget about
1079 * it immediately. NOTE: We don't set SIGCONT in p_sigignore,
1080 * and if it is set to SIG_IGN, action will be SIG_DFL here.
1082 if (SIGISMEMBER(p->p_sigignore, sig)) {
1084 * Even if a signal is set SIG_IGN, it may still be
1085 * lurking in a kqueue.
1087 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1088 lwkt_reltoken(&p->p_token);
1092 if (SIGISMEMBER(p->p_sigcatch, sig))
1099 * If continuing, clear any pending STOP signals.
1102 SIG_STOPSIGMASK(p->p_siglist);
1104 if (prop & SA_STOP) {
1106 * If sending a tty stop signal to a member of an orphaned
1107 * process group, discard the signal here if the action
1108 * is default; don't stop the process below if sleeping,
1109 * and don't clear any pending SIGCONT.
1111 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
1112 action == SIG_DFL) {
1113 lwkt_reltoken(&p->p_token);
1117 SIG_CONTSIGMASK(p->p_siglist);
1118 p->p_flag &= ~P_CONTINUED;
1123 if (p->p_stat == SSTOP) {
1125 * Nobody can handle this signal, add it to the lwp or
1126 * process pending list
1129 SIGADDSET(lp->lwp_siglist, sig);
1131 SIGADDSET(p->p_siglist, sig);
1134 * If the process is stopped and is being traced, then no
1135 * further action is necessary.
1137 if (p->p_flag & P_TRACED)
1141 * If the process is stopped and receives a KILL signal,
1142 * make the process runnable.
1144 if (sig == SIGKILL) {
1146 goto active_process;
1150 * If the process is stopped and receives a CONT signal,
1151 * then try to make the process runnable again.
1153 if (prop & SA_CONT) {
1155 * If SIGCONT is default (or ignored), we continue the
1156 * process but don't leave the signal in p_siglist, as
1157 * it has no further action. If SIGCONT is held, we
1158 * continue the process and leave the signal in
1159 * p_siglist. If the process catches SIGCONT, let it
1160 * handle the signal itself.
1162 /* XXX what if the signal is being held blocked? */
1163 p->p_flag |= P_CONTINUED;
1165 if (action == SIG_DFL)
1166 SIGDELSET(p->p_siglist, sig);
1168 if (action == SIG_CATCH)
1169 goto active_process;
1174 * If the process is stopped and receives another STOP
1175 * signal, we do not need to stop it again. If we did
1176 * the shell could get confused.
1178 * However, if the current/preempted lwp is part of the
1179 * process receiving the signal, we need to keep it,
1180 * so that this lwp can stop in issignal() later, as
1181 * we don't want to wait until it reaches userret!
1183 if (prop & SA_STOP) {
1184 if (lwkt_preempted_proc() == NULL ||
1185 lwkt_preempted_proc()->lwp_proc != p)
1186 SIGDELSET(p->p_siglist, sig);
1190 * Otherwise the process is stopped and it received some
1191 * signal, which does not change its stopped state.
1193 * We have to select one thread to set LWP_BREAKTSLEEP,
1194 * so that the current signal will break the sleep
1195 * as soon as a SA_CONT signal will unstop the process.
1198 lp = find_lwp_for_signal(p, sig);
1200 (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP))
1201 lp->lwp_flag |= LWP_BREAKTSLEEP;
1206 /* else not stopped */
1210 * Never deliver a lwp-specific signal to a random lwp.
1213 lp = find_lwp_for_signal(p, sig);
1214 if (lp && SIGISMEMBER(lp->lwp_sigmask, sig))
1219 * Deliver to the process generically if (1) the signal is being
1220 * sent to any thread or (2) we could not find a thread to deliver
1224 SIGADDSET(p->p_siglist, sig);
1229 * Deliver to a specific LWP whether it masks it or not. It will
1230 * not be dispatched if masked but we must still deliver it.
1232 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1233 (p->p_flag & P_TRACED) == 0) {
1238 * If the process receives a STOP signal which indeed needs to
1239 * stop the process, do so. If the process chose to catch the
1240 * signal, it will be treated like any other signal.
1242 if ((prop & SA_STOP) && action == SIG_DFL) {
1244 * If a child holding parent blocked, stopping
1245 * could cause deadlock. Take no action at this
1248 if (p->p_flag & P_PPWAIT) {
1249 SIGADDSET(p->p_siglist, sig);
1254 * Do not actually try to manipulate the process, but simply
1255 * stop it. Lwps will stop as soon as they safely can.
1263 * If it is a CONT signal with default action, just ignore it.
1265 if ((prop & SA_CONT) && action == SIG_DFL)
1269 * Mark signal pending at this specific thread.
1271 SIGADDSET(lp->lwp_siglist, sig);
1276 lwkt_reltoken(&p->p_token);
1282 * p->p_token must be held
1285 lwp_signotify(struct lwp *lp)
1287 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token);
1290 if (lp->lwp_stat == LSSLEEP || lp->lwp_stat == LSSTOP) {
1292 * Thread is in tsleep.
1296 * If the thread is sleeping uninterruptibly
1297 * we can't interrupt the sleep... the signal will
1298 * be noticed when the lwp returns through
1299 * trap() or syscall().
1301 * Otherwise the signal can interrupt the sleep.
1303 * If the process is traced, the lwp will handle the
1304 * tracing in issignal() when it returns to userland.
1306 if (lp->lwp_flag & LWP_SINTR) {
1308 * Make runnable and break out of any tsleep as well.
1310 lp->lwp_flag |= LWP_BREAKTSLEEP;
1315 * Otherwise the thread is running
1317 * LSRUN does nothing with the signal, other than kicking
1318 * ourselves if we are running.
1319 * SZOMB and SIDL mean that it will either never be noticed,
1320 * or noticed very soon.
1322 * Note that lwp_thread may be NULL or may not be completely
1323 * initialized if the process is in the SIDL or SZOMB state.
1325 * For SMP we may have to forward the request to another cpu.
1326 * YYY the MP lock prevents the target process from moving
1327 * to another cpu, see kern/kern_switch.c
1329 * If the target thread is waiting on its message port,
1330 * wakeup the target thread so it can check (or ignore)
1331 * the new signal. YYY needs cleanup.
1333 if (lp == lwkt_preempted_proc()) {
1335 } else if (lp->lwp_stat == LSRUN) {
1336 struct thread *td = lp->lwp_thread;
1337 struct proc *p __debugvar = lp->lwp_proc;
1340 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x",
1341 p->p_pid, lp->lwp_tid, lp->lwp_stat,
1342 p->p_flag, lp->lwp_flag));
1345 * To prevent a MP race with TDF_SINTR we must
1346 * schedule the thread on the correct cpu.
1349 if (td->td_gd != mycpu) {
1351 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1354 if (td->td_flags & TDF_SINTR)
1364 * This function is called via an IPI. We will be in a critical section but
1365 * the MP lock will NOT be held. The passed lp will be held.
1367 * We must essentially repeat the code at the end of lwp_signotify(),
1368 * in particular rechecking all races. If we are still not on the
1369 * correct cpu we leave the lwp ref intact and continue the chase.
1371 * XXX this may still not be entirely correct, since we are checking
1372 * lwp_stat asynchronously.
1375 signotify_remote(void *arg)
1377 struct lwp *lp = arg;
1380 if (lp == lwkt_preempted_proc()) {
1382 } else if (lp->lwp_stat == LSRUN) {
1384 * To prevent a MP race with TDF_SINTR we must
1385 * schedule the thread on the correct cpu.
1387 td = lp->lwp_thread;
1388 if (td->td_gd != mycpu) {
1389 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1393 if (td->td_flags & TDF_SINTR)
1402 * Caller must hold p->p_token
1405 proc_stop(struct proc *p)
1409 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1412 /* If somebody raced us, be happy with it */
1413 if (p->p_stat == SSTOP || p->p_stat == SZOMB) {
1419 FOREACH_LWP_IN_PROC(lp, p) {
1420 switch (lp->lwp_stat) {
1423 * Do nothing, we are already counted in
1430 * We're sleeping, but we will stop before
1431 * returning to userspace, so count us
1432 * as stopped as well. We set LWP_WSTOP
1433 * to signal the lwp that it should not
1434 * increase p_nstopped when reaching tstop().
1436 if ((lp->lwp_flag & LWP_WSTOP) == 0) {
1437 lp->lwp_flag |= LWP_WSTOP;
1444 * We might notify ourself, but that's not
1452 if (p->p_nstopped == p->p_nthreads) {
1453 p->p_flag &= ~P_WAITED;
1455 if ((p->p_pptr->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1456 ksignal(p->p_pptr, SIGCHLD);
1462 * Caller must hold proc_token
1465 proc_unstop(struct proc *p)
1469 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1472 if (p->p_stat != SSTOP) {
1477 p->p_stat = SACTIVE;
1479 FOREACH_LWP_IN_PROC(lp, p) {
1480 switch (lp->lwp_stat) {
1483 * Uh? Not stopped? Well, I guess that's okay.
1486 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1487 p->p_pid, lp->lwp_tid);
1492 * Still sleeping. Don't bother waking it up.
1493 * However, if this thread was counted as
1494 * stopped, undo this.
1496 * Nevertheless we call setrunnable() so that it
1497 * will wake up in case a signal or timeout arrived
1500 if (lp->lwp_flag & LWP_WSTOP) {
1501 lp->lwp_flag &= ~LWP_WSTOP;
1505 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n",
1506 p->p_pid, lp->lwp_tid);
1523 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1525 sigset_t savedmask, set;
1526 struct proc *p = curproc;
1527 struct lwp *lp = curthread->td_lwp;
1528 int error, sig, hz, timevalid = 0;
1529 struct timespec rts, ets, ts;
1534 ets.tv_sec = 0; /* silence compiler warning */
1535 ets.tv_nsec = 0; /* silence compiler warning */
1536 SIG_CANTMASK(waitset);
1537 savedmask = lp->lwp_sigmask;
1540 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1541 timeout->tv_nsec < 1000000000) {
1543 getnanouptime(&rts);
1545 timespecadd(&ets, timeout);
1550 set = lwp_sigpend(lp);
1551 SIGSETAND(set, waitset);
1552 if ((sig = sig_ffs(&set)) != 0) {
1553 SIGFILLSET(lp->lwp_sigmask);
1554 SIGDELSET(lp->lwp_sigmask, sig);
1555 SIG_CANTMASK(lp->lwp_sigmask);
1556 sig = issignal(lp, 1);
1558 * It may be a STOP signal, in the case, issignal
1559 * returns 0, because we may stop there, and new
1560 * signal can come in, we should restart if we got
1570 * Previous checking got nothing, and we retried but still
1571 * got nothing, we should return the error status.
1577 * POSIX says this must be checked after looking for pending
1581 if (timevalid == 0) {
1585 getnanouptime(&rts);
1586 if (timespeccmp(&rts, &ets, >=)) {
1591 timespecsub(&ts, &rts);
1592 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1593 hz = tvtohz_high(&tv);
1598 lp->lwp_sigmask = savedmask;
1599 SIGSETNAND(lp->lwp_sigmask, waitset);
1601 * We won't ever be woken up. Instead, our sleep will
1602 * be broken in lwpsignal().
1604 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1606 if (error == ERESTART) {
1607 /* can not restart a timeout wait. */
1609 } else if (error == EAGAIN) {
1610 /* will calculate timeout by ourself. */
1617 lp->lwp_sigmask = savedmask;
1620 bzero(info, sizeof(*info));
1621 info->si_signo = sig;
1622 lwp_delsig(lp, sig); /* take the signal! */
1624 if (sig == SIGKILL) {
1637 sys_sigtimedwait(struct sigtimedwait_args *uap)
1640 struct timespec *timeout;
1646 error = copyin(uap->timeout, &ts, sizeof(ts));
1653 error = copyin(uap->set, &set, sizeof(set));
1656 error = kern_sigtimedwait(set, &info, timeout);
1660 error = copyout(&info, uap->info, sizeof(info));
1661 /* Repost if we got an error. */
1665 * This could transform a thread-specific signal to another
1666 * thread / process pending signal.
1669 ksignal(curproc, info.si_signo);
1671 uap->sysmsg_result = info.si_signo;
1680 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1686 error = copyin(uap->set, &set, sizeof(set));
1689 error = kern_sigtimedwait(set, &info, NULL);
1693 error = copyout(&info, uap->info, sizeof(info));
1694 /* Repost if we got an error. */
1698 * This could transform a thread-specific signal to another
1699 * thread / process pending signal.
1702 ksignal(curproc, info.si_signo);
1704 uap->sysmsg_result = info.si_signo;
1710 * If the current process has received a signal that would interrupt a
1711 * system call, return EINTR or ERESTART as appropriate.
1714 iscaught(struct lwp *lp)
1716 struct proc *p = lp->lwp_proc;
1720 if ((sig = CURSIG(lp)) != 0) {
1721 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1726 return(EWOULDBLOCK);
1730 * If the current process has received a signal (should be caught or cause
1731 * termination, should interrupt current syscall), return the signal number.
1732 * Stop signals with default action are processed immediately, then cleared;
1733 * they aren't returned. This is checked after each entry to the system for
1734 * a syscall or trap (though this can usually be done without calling issignal
1735 * by checking the pending signal masks in the CURSIG macro).
1737 * This routine is called via CURSIG/__cursig. We will acquire and release
1738 * p->p_token but if the caller needs to interlock the test the caller must
1739 * also hold p->p_token.
1741 * while (sig = CURSIG(curproc))
1747 issignal(struct lwp *lp, int maytrace)
1749 struct proc *p = lp->lwp_proc;
1753 lwkt_gettoken(&p->p_token);
1756 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1759 * If this process is supposed to stop, stop this thread.
1761 if (p->p_stat == SSTOP)
1764 mask = lwp_sigpend(lp);
1765 SIGSETNAND(mask, lp->lwp_sigmask);
1766 if (p->p_flag & P_PPWAIT)
1767 SIG_STOPSIGMASK(mask);
1768 if (SIGISEMPTY(mask)) { /* no signal to send */
1769 lwkt_reltoken(&p->p_token);
1772 sig = sig_ffs(&mask);
1774 STOPEVENT(p, S_SIG, sig);
1777 * We should see pending but ignored signals
1778 * only if P_TRACED was on when they were posted.
1780 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1781 lwp_delsig(lp, sig);
1784 if (maytrace && (p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1786 * If traced, always stop, and stay stopped until
1787 * released by the parent.
1789 * NOTE: SSTOP may get cleared during the loop,
1790 * but we do not re-notify the parent if we have
1791 * to loop several times waiting for the parent
1792 * to let us continue.
1794 * XXX not sure if this is still true
1800 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1803 * If parent wants us to take the signal,
1804 * then it will leave it in p->p_xstat;
1805 * otherwise we just look for signals again.
1807 lwp_delsig(lp, sig); /* clear old signal */
1813 * Put the new signal into p_siglist. If the
1814 * signal is being masked, look for other signals.
1816 * XXX lwp might need a call to ksignal()
1818 SIGADDSET(p->p_siglist, sig);
1819 if (SIGISMEMBER(lp->lwp_sigmask, sig))
1823 * If the traced bit got turned off, go back up
1824 * to the top to rescan signals. This ensures
1825 * that p_sig* and ps_sigact are consistent.
1827 if ((p->p_flag & P_TRACED) == 0)
1831 prop = sigprop(sig);
1834 * Decide whether the signal should be returned.
1835 * Return the signal's number, or fall through
1836 * to clear it from the pending mask.
1838 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1839 case (intptr_t)SIG_DFL:
1841 * Don't take default actions on system processes.
1843 if (p->p_pid <= 1) {
1846 * Are you sure you want to ignore SIGSEGV
1849 kprintf("Process (pid %lu) got signal %d\n",
1850 (u_long)p->p_pid, sig);
1852 break; /* == ignore */
1856 * Handle the in-kernel checkpoint action
1858 if (prop & SA_CKPT) {
1859 checkpoint_signal_handler(lp);
1864 * If there is a pending stop signal to process
1865 * with default action, stop here,
1866 * then clear the signal. However,
1867 * if process is member of an orphaned
1868 * process group, ignore tty stop signals.
1870 if (prop & SA_STOP) {
1871 if (p->p_flag & P_TRACED ||
1872 (p->p_pgrp->pg_jobc == 0 &&
1874 break; /* == ignore */
1879 } else if (prop & SA_IGNORE) {
1881 * Except for SIGCONT, shouldn't get here.
1882 * Default action is to ignore; drop it.
1884 break; /* == ignore */
1886 lwkt_reltoken(&p->p_token);
1892 case (intptr_t)SIG_IGN:
1894 * Masking above should prevent us ever trying
1895 * to take action on an ignored signal other
1896 * than SIGCONT, unless process is traced.
1898 if ((prop & SA_CONT) == 0 &&
1899 (p->p_flag & P_TRACED) == 0)
1900 kprintf("issignal\n");
1901 break; /* == ignore */
1905 * This signal has an action, let
1906 * postsig() process it.
1908 lwkt_reltoken(&p->p_token);
1911 lwp_delsig(lp, sig); /* take the signal! */
1917 * Take the action for the specified signal
1918 * from the current set of pending signals.
1923 struct lwp *lp = curthread->td_lwp;
1924 struct proc *p = lp->lwp_proc;
1925 struct sigacts *ps = p->p_sigacts;
1927 sigset_t returnmask;
1930 KASSERT(sig != 0, ("postsig"));
1932 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1935 * If we are a virtual kernel running an emulated user process
1936 * context, switch back to the virtual kernel context before
1937 * trying to post the signal.
1939 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
1940 struct trapframe *tf = lp->lwp_md.md_regs;
1942 vkernel_trap(lp, tf);
1945 lwp_delsig(lp, sig);
1946 action = ps->ps_sigact[_SIG_IDX(sig)];
1948 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
1949 ktrpsig(lp, sig, action, lp->lwp_flag & LWP_OLDMASK ?
1950 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
1952 STOPEVENT(p, S_SIG, sig);
1954 if (action == SIG_DFL) {
1956 * Default action, where the default is to kill
1957 * the process. (Other cases were ignored above.)
1963 * If we get here, the signal must be caught.
1965 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
1966 ("postsig action"));
1971 * Reset the signal handler if asked to
1973 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1975 * See kern_sigaction() for origin of this code.
1977 SIGDELSET(p->p_sigcatch, sig);
1978 if (sig != SIGCONT &&
1979 sigprop(sig) & SA_IGNORE)
1980 SIGADDSET(p->p_sigignore, sig);
1981 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1985 * Handle the mailbox case. Copyout to the appropriate
1986 * location but do not generate a signal frame. The system
1987 * call simply returns EINTR and the user is responsible for
1988 * polling the mailbox.
1990 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) {
1992 copyout(&sig_copy, (void *)action, sizeof(int));
1993 curproc->p_flag |= P_MAILBOX;
1999 * Set the signal mask and calculate the mask to restore
2000 * when the signal function returns.
2002 * Special case: user has done a sigsuspend. Here the
2003 * current mask is not of interest, but rather the
2004 * mask from before the sigsuspend is what we want
2005 * restored after the signal processing is completed.
2007 if (lp->lwp_flag & LWP_OLDMASK) {
2008 returnmask = lp->lwp_oldsigmask;
2009 lp->lwp_flag &= ~LWP_OLDMASK;
2011 returnmask = lp->lwp_sigmask;
2014 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
2015 if (!SIGISMEMBER(ps->ps_signodefer, sig))
2016 SIGADDSET(lp->lwp_sigmask, sig);
2019 lp->lwp_ru.ru_nsignals++;
2020 if (lp->lwp_sig != sig) {
2023 code = lp->lwp_code;
2027 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
2034 * Kill the current process for stated reason.
2037 killproc(struct proc *p, char *why)
2039 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
2040 p->p_pid, p->p_comm,
2041 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
2042 ksignal(p, SIGKILL);
2046 * Force the current process to exit with the specified signal, dumping core
2047 * if appropriate. We bypass the normal tests for masked and caught signals,
2048 * allowing unrecoverable failures to terminate the process without changing
2049 * signal state. Mark the accounting record with the signal termination.
2050 * If dumping core, save the signal number for the debugger. Calls exit and
2053 * This routine does not return.
2056 sigexit(struct lwp *lp, int sig)
2058 struct proc *p = lp->lwp_proc;
2060 lwkt_gettoken(&p->p_token);
2061 p->p_acflag |= AXSIG;
2062 if (sigprop(sig) & SA_CORE) {
2065 * Log signals which would cause core dumps
2066 * (Log as LOG_INFO to appease those who don't want
2068 * XXX : Todo, as well as euid, write out ruid too
2070 if (coredump(lp, sig) == 0)
2072 if (kern_logsigexit)
2074 "pid %d (%s), uid %d: exited on signal %d%s\n",
2075 p->p_pid, p->p_comm,
2076 p->p_ucred ? p->p_ucred->cr_uid : -1,
2078 sig & WCOREFLAG ? " (core dumped)" : "");
2080 lwkt_reltoken(&p->p_token);
2081 exit1(W_EXITCODE(0, sig));
2085 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
2086 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
2087 sizeof(corefilename), "process corefile name format string");
2090 * expand_name(name, uid, pid)
2091 * Expand the name described in corefilename, using name, uid, and pid.
2092 * corefilename is a kprintf-like string, with three format specifiers:
2093 * %N name of process ("name")
2094 * %P process id (pid)
2096 * For example, "%N.core" is the default; they can be disabled completely
2097 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
2098 * This is controlled by the sysctl variable kern.corefile (see above).
2102 expand_name(const char *name, uid_t uid, pid_t pid)
2105 char buf[11]; /* Buffer for pid/uid -- max 4B */
2107 char *format = corefilename;
2110 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
2113 namelen = strlen(name);
2114 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
2116 switch (format[i]) {
2117 case '%': /* Format character */
2119 switch (format[i]) {
2123 case 'N': /* process name */
2124 if ((n + namelen) > MAXPATHLEN) {
2125 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2126 pid, name, uid, temp, name);
2127 kfree(temp, M_TEMP);
2130 memcpy(temp+n, name, namelen);
2133 case 'P': /* process id */
2134 l = ksprintf(buf, "%u", pid);
2135 if ((n + l) > MAXPATHLEN) {
2136 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2137 pid, name, uid, temp, name);
2138 kfree(temp, M_TEMP);
2141 memcpy(temp+n, buf, l);
2144 case 'U': /* user id */
2145 l = ksprintf(buf, "%u", uid);
2146 if ((n + l) > MAXPATHLEN) {
2147 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2148 pid, name, uid, temp, name);
2149 kfree(temp, M_TEMP);
2152 memcpy(temp+n, buf, l);
2156 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
2160 temp[n++] = format[i];
2168 * Dump a process' core. The main routine does some
2169 * policy checking, and creates the name of the coredump;
2170 * then it passes on a vnode and a size limit to the process-specific
2171 * coredump routine if there is one; if there _is not_ one, it returns
2172 * ENOSYS; otherwise it returns the error from the process-specific routine.
2174 * The parameter `lp' is the lwp which triggered the coredump.
2178 coredump(struct lwp *lp, int sig)
2180 struct proc *p = lp->lwp_proc;
2182 struct ucred *cred = p->p_ucred;
2184 struct nlookupdata nd;
2187 char *name; /* name of corefile */
2190 STOPEVENT(p, S_CORE, 0);
2192 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
2196 * Note that the bulk of limit checking is done after
2197 * the corefile is created. The exception is if the limit
2198 * for corefiles is 0, in which case we don't bother
2199 * creating the corefile at all. This layout means that
2200 * a corefile is truncated instead of not being created,
2201 * if it is larger than the limit.
2203 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
2207 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
2210 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
2212 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
2213 kfree(name, M_TEMP);
2219 nd.nl_open_vp = NULL;
2223 lf.l_whence = SEEK_SET;
2226 lf.l_type = F_WRLCK;
2227 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2231 /* Don't dump to non-regular files or files with links. */
2232 if (vp->v_type != VREG ||
2233 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2238 /* Don't dump to files current user does not own */
2239 if (vattr.va_uid != p->p_ucred->cr_uid) {
2245 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2247 VOP_SETATTR(vp, &vattr, cred);
2248 p->p_acflag |= ACORE;
2251 error = p->p_sysent->sv_coredump ?
2252 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2255 lf.l_type = F_UNLCK;
2256 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2258 error1 = vn_close(vp, FWRITE);
2265 * Nonexistent system call-- signal process (may want to handle it).
2266 * Flag error in case process won't see signal immediately (blocked or ignored).
2272 sys_nosys(struct nosys_args *args)
2274 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2279 * Send a SIGIO or SIGURG signal to a process or process group using
2280 * stored credentials rather than those of the current process.
2283 pgsigio(struct sigio *sigio, int sig, int checkctty)
2288 if (sigio->sio_pgid > 0) {
2289 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2291 ksignal(sigio->sio_proc, sig);
2292 } else if (sigio->sio_pgid < 0) {
2294 struct pgrp *pg = sigio->sio_pgrp;
2297 * Must interlock all signals against fork
2300 lockmgr(&pg->pg_lock, LK_EXCLUSIVE);
2301 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
2302 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2303 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
2306 lockmgr(&pg->pg_lock, LK_RELEASE);
2312 filt_sigattach(struct knote *kn)
2314 struct proc *p = curproc;
2316 kn->kn_ptr.p_proc = p;
2317 kn->kn_flags |= EV_CLEAR; /* automatically set */
2319 /* XXX lock the proc here while adding to the list? */
2320 knote_insert(&p->p_klist, kn);
2326 filt_sigdetach(struct knote *kn)
2328 struct proc *p = kn->kn_ptr.p_proc;
2330 knote_remove(&p->p_klist, kn);
2334 * signal knotes are shared with proc knotes, so we apply a mask to
2335 * the hint in order to differentiate them from process hints. This
2336 * could be avoided by using a signal-specific knote list, but probably
2337 * isn't worth the trouble.
2340 filt_signal(struct knote *kn, long hint)
2342 if (hint & NOTE_SIGNAL) {
2343 hint &= ~NOTE_SIGNAL;
2345 if (kn->kn_id == hint)
2348 return (kn->kn_data != 0);