/* $NetBSD: kern_sig.c,v 1.129 2002/12/06 22:44:49 christos Exp $ */ /* * Copyright (c) 1982, 1986, 1989, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_sig.c 8.14 (Berkeley) 5/14/95 */ #include __KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.129 2002/12/06 22:44:49 christos Exp $"); #include "opt_ktrace.h" #include "opt_compat_sunos.h" #include "opt_compat_netbsd32.h" #define SIGPROP /* include signal properties table */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for coredump */ #include static void proc_stop(struct proc *p); static int build_corename(struct proc *, char [MAXPATHLEN]); sigset_t contsigmask, stopsigmask, sigcantmask; struct pool sigacts_pool; /* memory pool for sigacts structures */ /* * Can process p, with pcred pc, send the signal signum to process q? */ #define CANSIGNAL(p, pc, q, signum) \ ((pc)->pc_ucred->cr_uid == 0 || \ (pc)->p_ruid == (q)->p_cred->p_ruid || \ (pc)->pc_ucred->cr_uid == (q)->p_cred->p_ruid || \ (pc)->p_ruid == (q)->p_ucred->cr_uid || \ (pc)->pc_ucred->cr_uid == (q)->p_ucred->cr_uid || \ ((signum) == SIGCONT && (q)->p_session == (p)->p_session)) /* * Initialize signal-related data structures. */ void signal_init(void) { pool_init(&sigacts_pool, sizeof(struct sigacts), 0, 0, 0, "sigapl", &pool_allocator_nointr); } /* * Create an initial sigctx structure, using the same signal state * as p. If 'share' is set, share the sigctx_proc part, otherwise just * copy it from parent. */ void sigactsinit(struct proc *np, struct proc *pp, int share) { struct sigacts *ps; if (share) { np->p_sigacts = pp->p_sigacts; pp->p_sigacts->sa_refcnt++; } else { ps = pool_get(&sigacts_pool, PR_WAITOK); if (pp) memcpy(ps, pp->p_sigacts, sizeof(struct sigacts)); else memset(ps, '\0', sizeof(struct sigacts)); ps->sa_refcnt = 1; np->p_sigacts = ps; } } /* * Make this process not share its sigctx, maintaining all * signal state. */ void sigactsunshare(struct proc *p) { struct sigacts *oldps; if (p->p_sigacts->sa_refcnt == 1) return; oldps = p->p_sigacts; sigactsinit(p, NULL, 0); if (--oldps->sa_refcnt == 0) pool_put(&sigacts_pool, oldps); } /* * Release a sigctx structure. */ void sigactsfree(struct proc *p) { struct sigacts *ps; ps = p->p_sigacts; if (--ps->sa_refcnt > 0) return; pool_put(&sigacts_pool, ps); } int sigaction1(struct proc *p, int signum, const struct sigaction *nsa, struct sigaction *osa, void *tramp, int vers) { struct sigacts *ps; int prop; ps = p->p_sigacts; if (signum <= 0 || signum >= NSIG) return (EINVAL); /* * Trampoline ABI version 0 is reserved for the legacy * kernel-provided on-stack trampoline. Conversely, if * we are using a non-0 ABI version, we must have a * trampoline. */ if ((vers != 0 && tramp == NULL) || (vers == 0 && tramp != NULL)) return (EINVAL); if (osa) *osa = SIGACTION_PS(ps, signum); if (nsa) { if (nsa->sa_flags & ~SA_ALLBITS) return (EINVAL); prop = sigprop[signum]; if (prop & SA_CANTMASK) return (EINVAL); (void) splsched(); /* XXXSMP */ SIGACTION_PS(ps, signum) = *nsa; ps->sa_sigdesc[signum].sd_tramp = tramp; ps->sa_sigdesc[signum].sd_vers = vers; sigminusset(&sigcantmask, &SIGACTION_PS(ps, signum).sa_mask); if ((prop & SA_NORESET) != 0) SIGACTION_PS(ps, signum).sa_flags &= ~SA_RESETHAND; if (signum == SIGCHLD) { if (nsa->sa_flags & SA_NOCLDSTOP) p->p_flag |= P_NOCLDSTOP; else p->p_flag &= ~P_NOCLDSTOP; if (nsa->sa_flags & SA_NOCLDWAIT) { /* * Paranoia: since SA_NOCLDWAIT is implemented * by reparenting the dying child to PID 1 (and * trust it to reap the zombie), PID 1 itself * is forbidden to set SA_NOCLDWAIT. */ if (p->p_pid == 1) p->p_flag &= ~P_NOCLDWAIT; else p->p_flag |= P_NOCLDWAIT; } else p->p_flag &= ~P_NOCLDWAIT; } if ((nsa->sa_flags & SA_NODEFER) == 0) sigaddset(&SIGACTION_PS(ps, signum).sa_mask, signum); else sigdelset(&SIGACTION_PS(ps, signum).sa_mask, signum); /* * Set bit in p_sigctx.ps_sigignore for signals that are set to * SIG_IGN, and for signals set to SIG_DFL where the default is * to ignore. However, don't put SIGCONT in * p_sigctx.ps_sigignore, as we have to restart the process. */ if (nsa->sa_handler == SIG_IGN || (nsa->sa_handler == SIG_DFL && (prop & SA_IGNORE) != 0)) { /* never to be seen again */ sigdelset(&p->p_sigctx.ps_siglist, signum); if (signum != SIGCONT) { /* easier in psignal */ sigaddset(&p->p_sigctx.ps_sigignore, signum); } sigdelset(&p->p_sigctx.ps_sigcatch, signum); } else { sigdelset(&p->p_sigctx.ps_sigignore, signum); if (nsa->sa_handler == SIG_DFL) sigdelset(&p->p_sigctx.ps_sigcatch, signum); else sigaddset(&p->p_sigctx.ps_sigcatch, signum); } (void) spl0(); } return (0); } /* ARGSUSED */ int sys___sigaction14(struct proc *p, void *v, register_t *retval) { struct sys___sigaction14_args /* { syscallarg(int) signum; syscallarg(const struct sigaction *) nsa; syscallarg(struct sigaction *) osa; } */ *uap = v; struct sigaction nsa, osa; int error; if (SCARG(uap, nsa)) { error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); if (error) return (error); } error = sigaction1(p, SCARG(uap, signum), SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, NULL, 0); if (error) return (error); if (SCARG(uap, osa)) { error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); if (error) return (error); } return (0); } /* ARGSUSED */ int sys___sigaction_sigtramp(struct proc *p, void *v, register_t *retval) { struct sys___sigaction_sigtramp_args /* { syscallarg(int) signum; syscallarg(const struct sigaction *) nsa; syscallarg(struct sigaction *) osa; syscallarg(void *) tramp; syscallarg(int) vers; } */ *uap = v; struct sigaction nsa, osa; int error; if (SCARG(uap, nsa)) { error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); if (error) return (error); } error = sigaction1(p, SCARG(uap, signum), SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, SCARG(uap, tramp), SCARG(uap, vers)); if (error) return (error); if (SCARG(uap, osa)) { error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); if (error) return (error); } return (0); } /* * Initialize signal state for process 0; * set to ignore signals that are ignored by default and disable the signal * stack. */ void siginit(struct proc *p) { struct sigacts *ps; int signum, prop; ps = p->p_sigacts; sigemptyset(&contsigmask); sigemptyset(&stopsigmask); sigemptyset(&sigcantmask); for (signum = 1; signum < NSIG; signum++) { prop = sigprop[signum]; if (prop & SA_CONT) sigaddset(&contsigmask, signum); if (prop & SA_STOP) sigaddset(&stopsigmask, signum); if (prop & SA_CANTMASK) sigaddset(&sigcantmask, signum); if (prop & SA_IGNORE && signum != SIGCONT) sigaddset(&p->p_sigctx.ps_sigignore, signum); sigemptyset(&SIGACTION_PS(ps, signum).sa_mask); SIGACTION_PS(ps, signum).sa_flags = SA_RESTART; } sigemptyset(&p->p_sigctx.ps_sigcatch); p->p_flag &= ~P_NOCLDSTOP; /* * Reset stack state to the user stack. */ p->p_sigctx.ps_sigstk.ss_flags = SS_DISABLE; p->p_sigctx.ps_sigstk.ss_size = 0; p->p_sigctx.ps_sigstk.ss_sp = 0; /* One reference. */ ps->sa_refcnt = 1; } /* * Reset signals for an exec of the specified process. */ void execsigs(struct proc *p) { struct sigacts *ps; int signum, prop; sigactsunshare(p); ps = p->p_sigacts; /* * Reset caught signals. Held signals remain held * through p_sigctx.ps_sigmask (unless they were caught, * and are now ignored by default). */ for (signum = 1; signum < NSIG; signum++) { if (sigismember(&p->p_sigctx.ps_sigcatch, signum)) { prop = sigprop[signum]; if (prop & SA_IGNORE) { if ((prop & SA_CONT) == 0) sigaddset(&p->p_sigctx.ps_sigignore, signum); sigdelset(&p->p_sigctx.ps_siglist, signum); } SIGACTION_PS(ps, signum).sa_handler = SIG_DFL; } sigemptyset(&SIGACTION_PS(ps, signum).sa_mask); SIGACTION_PS(ps, signum).sa_flags = SA_RESTART; } sigemptyset(&p->p_sigctx.ps_sigcatch); p->p_flag &= ~P_NOCLDSTOP; /* * Reset stack state to the user stack. */ p->p_sigctx.ps_sigstk.ss_flags = SS_DISABLE; p->p_sigctx.ps_sigstk.ss_size = 0; p->p_sigctx.ps_sigstk.ss_sp = 0; } int sigprocmask1(struct proc *p, int how, const sigset_t *nss, sigset_t *oss) { if (oss) *oss = p->p_sigctx.ps_sigmask; if (nss) { (void)splsched(); /* XXXSMP */ switch (how) { case SIG_BLOCK: sigplusset(nss, &p->p_sigctx.ps_sigmask); break; case SIG_UNBLOCK: sigminusset(nss, &p->p_sigctx.ps_sigmask); CHECKSIGS(p); break; case SIG_SETMASK: p->p_sigctx.ps_sigmask = *nss; CHECKSIGS(p); break; default: (void)spl0(); /* XXXSMP */ return (EINVAL); } sigminusset(&sigcantmask, &p->p_sigctx.ps_sigmask); (void)spl0(); /* XXXSMP */ } return (0); } /* * Manipulate signal mask. * Note that we receive new mask, not pointer, * and return old mask as return value; * the library stub does the rest. */ int sys___sigprocmask14(struct proc *p, void *v, register_t *retval) { struct sys___sigprocmask14_args /* { syscallarg(int) how; syscallarg(const sigset_t *) set; syscallarg(sigset_t *) oset; } */ *uap = v; sigset_t nss, oss; int error; if (SCARG(uap, set)) { error = copyin(SCARG(uap, set), &nss, sizeof(nss)); if (error) return (error); } error = sigprocmask1(p, SCARG(uap, how), SCARG(uap, set) ? &nss : 0, SCARG(uap, oset) ? &oss : 0); if (error) return (error); if (SCARG(uap, oset)) { error = copyout(&oss, SCARG(uap, oset), sizeof(oss)); if (error) return (error); } return (0); } void sigpending1(struct proc *p, sigset_t *ss) { *ss = p->p_sigctx.ps_siglist; sigminusset(&p->p_sigctx.ps_sigmask, ss); } /* ARGSUSED */ int sys___sigpending14(struct proc *p, void *v, register_t *retval) { struct sys___sigpending14_args /* { syscallarg(sigset_t *) set; } */ *uap = v; sigset_t ss; sigpending1(p, &ss); return (copyout(&ss, SCARG(uap, set), sizeof(ss))); } int sigsuspend1(struct proc *p, const sigset_t *ss) { struct sigacts *ps; ps = p->p_sigacts; if (ss) { /* * When returning from sigpause, we want * the old mask to be restored after the * signal handler has finished. Thus, we * save it here and mark the sigctx structure * to indicate this. */ p->p_sigctx.ps_oldmask = p->p_sigctx.ps_sigmask; p->p_sigctx.ps_flags |= SAS_OLDMASK; (void) splsched(); /* XXXSMP */ p->p_sigctx.ps_sigmask = *ss; CHECKSIGS(p); sigminusset(&sigcantmask, &p->p_sigctx.ps_sigmask); (void) spl0(); /* XXXSMP */ } while (tsleep((caddr_t) ps, PPAUSE|PCATCH, "pause", 0) == 0) /* void */; /* always return EINTR rather than ERESTART... */ return (EINTR); } /* * Suspend process until signal, providing mask to be set * in the meantime. Note nonstandard calling convention: * libc stub passes mask, not pointer, to save a copyin. */ /* ARGSUSED */ int sys___sigsuspend14(struct proc *p, void *v, register_t *retval) { struct sys___sigsuspend14_args /* { syscallarg(const sigset_t *) set; } */ *uap = v; sigset_t ss; int error; if (SCARG(uap, set)) { error = copyin(SCARG(uap, set), &ss, sizeof(ss)); if (error) return (error); } return (sigsuspend1(p, SCARG(uap, set) ? &ss : 0)); } int sigaltstack1(struct proc *p, const struct sigaltstack *nss, struct sigaltstack *oss) { if (oss) *oss = p->p_sigctx.ps_sigstk; if (nss) { if (nss->ss_flags & ~SS_ALLBITS) return (EINVAL); if (nss->ss_flags & SS_DISABLE) { if (p->p_sigctx.ps_sigstk.ss_flags & SS_ONSTACK) return (EINVAL); } else { if (nss->ss_size < MINSIGSTKSZ) return (ENOMEM); } p->p_sigctx.ps_sigstk = *nss; } return (0); } /* ARGSUSED */ int sys___sigaltstack14(struct proc *p, void *v, register_t *retval) { struct sys___sigaltstack14_args /* { syscallarg(const struct sigaltstack *) nss; syscallarg(struct sigaltstack *) oss; } */ *uap = v; struct sigaltstack nss, oss; int error; if (SCARG(uap, nss)) { error = copyin(SCARG(uap, nss), &nss, sizeof(nss)); if (error) return (error); } error = sigaltstack1(p, SCARG(uap, nss) ? &nss : 0, SCARG(uap, oss) ? &oss : 0); if (error) return (error); if (SCARG(uap, oss)) { error = copyout(&oss, SCARG(uap, oss), sizeof(oss)); if (error) return (error); } return (0); } /* ARGSUSED */ int sys_kill(struct proc *cp, void *v, register_t *retval) { struct sys_kill_args /* { syscallarg(int) pid; syscallarg(int) signum; } */ *uap = v; struct proc *p; struct pcred *pc; pc = cp->p_cred; if ((u_int)SCARG(uap, signum) >= NSIG) return (EINVAL); if (SCARG(uap, pid) > 0) { /* kill single process */ if ((p = pfind(SCARG(uap, pid))) == NULL) return (ESRCH); if (!CANSIGNAL(cp, pc, p, SCARG(uap, signum))) return (EPERM); if (SCARG(uap, signum)) psignal(p, SCARG(uap, signum)); return (0); } switch (SCARG(uap, pid)) { case -1: /* broadcast signal */ return (killpg1(cp, SCARG(uap, signum), 0, 1)); case 0: /* signal own process group */ return (killpg1(cp, SCARG(uap, signum), 0, 0)); default: /* negative explicit process group */ return (killpg1(cp, SCARG(uap, signum), -SCARG(uap, pid), 0)); } /* NOTREACHED */ } /* * Common code for kill process group/broadcast kill. * cp is calling process. */ int killpg1(struct proc *cp, int signum, int pgid, int all) { struct proc *p; struct pcred *pc; struct pgrp *pgrp; int nfound; pc = cp->p_cred; nfound = 0; if (all) { /* * broadcast */ proclist_lock_read(); LIST_FOREACH(p, &allproc, p_list) { if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || p == cp || !CANSIGNAL(cp, pc, p, signum)) continue; nfound++; if (signum) psignal(p, signum); } proclist_unlock_read(); } else { if (pgid == 0) /* * zero pgid means send to my process group. */ pgrp = cp->p_pgrp; else { pgrp = pgfind(pgid); if (pgrp == NULL) return (ESRCH); } LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || !CANSIGNAL(cp, pc, p, signum)) continue; nfound++; if (signum && P_ZOMBIE(p) == 0) psignal(p, signum); } } return (nfound ? 0 : ESRCH); } /* * Send a signal to a process group. */ void gsignal(int pgid, int signum) { struct pgrp *pgrp; if (pgid && (pgrp = pgfind(pgid))) pgsignal(pgrp, signum, 0); } /* * Send a signal to a process group. If checktty is 1, * limit to members which have a controlling terminal. */ void pgsignal(struct pgrp *pgrp, int signum, int checkctty) { struct proc *p; if (pgrp) LIST_FOREACH(p, &pgrp->pg_members, p_pglist) if (checkctty == 0 || p->p_flag & P_CONTROLT) psignal(p, signum); } /* * Send a signal caused by a trap to the current process. * If it will be caught immediately, deliver it with correct code. * Otherwise, post it normally. */ void trapsignal(struct proc *p, int signum, u_long code) { struct sigacts *ps; ps = p->p_sigacts; if ((p->p_flag & P_TRACED) == 0 && sigismember(&p->p_sigctx.ps_sigcatch, signum) && !sigismember(&p->p_sigctx.ps_sigmask, signum)) { p->p_stats->p_ru.ru_nsignals++; #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) ktrpsig(p, signum, SIGACTION_PS(ps, signum).sa_handler, &p->p_sigctx.ps_sigmask, code); #endif (*p->p_emul->e_sendsig)(signum, &p->p_sigctx.ps_sigmask, code); (void) splsched(); /* XXXSMP */ sigplusset(&SIGACTION_PS(ps, signum).sa_mask, &p->p_sigctx.ps_sigmask); if (SIGACTION_PS(ps, signum).sa_flags & SA_RESETHAND) { sigdelset(&p->p_sigctx.ps_sigcatch, signum); if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) sigaddset(&p->p_sigctx.ps_sigignore, signum); SIGACTION_PS(ps, signum).sa_handler = SIG_DFL; } (void) spl0(); /* XXXSMP */ } else { p->p_sigctx.ps_code = code; /* XXX for core dump/debugger */ p->p_sigctx.ps_sig = signum; /* XXX to verify code */ psignal(p, signum); } } /* * Send the signal to the process. If the signal has an action, the action * is usually performed by the target process rather than the caller; we add * the signal to the set of pending signals for the process. * * Exceptions: * o When a stop signal is sent to a sleeping process that takes the * default action, the process is stopped without awakening it. * o SIGCONT restarts stopped processes (or puts them back to sleep) * regardless of the signal action (eg, blocked or ignored). * * Other ignored signals are discarded immediately. * * XXXSMP: Invoked as psignal() or sched_psignal(). */ void psignal1(struct proc *p, int signum, int dolock) /* XXXSMP: works, but icky */ { int s = 0, prop; sig_t action; #ifdef DIAGNOSTIC if (signum <= 0 || signum >= NSIG) panic("psignal signal number"); /* XXXSMP: works, but icky */ if (dolock) SCHED_ASSERT_UNLOCKED(); else SCHED_ASSERT_LOCKED(); #endif /* * Notify any interested parties in the signal. */ KNOTE(&p->p_klist, NOTE_SIGNAL | signum); prop = sigprop[signum]; /* * If proc is traced, always give parent a chance. */ if (p->p_flag & P_TRACED) action = SIG_DFL; else { /* * If the signal is being ignored, * then we forget about it immediately. * (Note: we don't set SIGCONT in p_sigctx.ps_sigignore, * and if it is set to SIG_IGN, * action will be SIG_DFL here.) */ if (sigismember(&p->p_sigctx.ps_sigignore, signum)) return; if (sigismember(&p->p_sigctx.ps_sigmask, signum)) action = SIG_HOLD; else if (sigismember(&p->p_sigctx.ps_sigcatch, signum)) action = SIG_CATCH; else { action = SIG_DFL; if (prop & SA_KILL && p->p_nice > NZERO) p->p_nice = NZERO; /* * If sending a tty stop signal to a member of an * orphaned process group, discard the signal here if * the action is default; don't stop the process below * if sleeping, and don't clear any pending SIGCONT. */ if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0) return; } } if (prop & SA_CONT) sigminusset(&stopsigmask, &p->p_sigctx.ps_siglist); if (prop & SA_STOP) sigminusset(&contsigmask, &p->p_sigctx.ps_siglist); sigaddset(&p->p_sigctx.ps_siglist, signum); /* CHECKSIGS() is "inlined" here. */ p->p_sigctx.ps_sigcheck = 1; /* * Defer further processing for signals which are held, * except that stopped processes must be continued by SIGCONT. */ if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) return; /* XXXSMP: works, but icky */ if (dolock) SCHED_LOCK(s); switch (p->p_stat) { case SSLEEP: /* * If process is sleeping uninterruptibly * we can't interrupt the sleep... the signal will * be noticed when the process returns through * trap() or syscall(). */ if ((p->p_flag & P_SINTR) == 0) goto out; /* * Process is sleeping and traced... make it runnable * so it can discover the signal in issignal() and stop * for the parent. */ if (p->p_flag & P_TRACED) goto run; /* * If SIGCONT is default (or ignored) and process is * asleep, we are finished; the process should not * be awakened. */ if ((prop & SA_CONT) && action == SIG_DFL) { sigdelset(&p->p_sigctx.ps_siglist, signum); goto out; } /* * When a sleeping process receives a stop * signal, process immediately if possible. */ if ((prop & SA_STOP) && action == SIG_DFL) { /* * If a child holding parent blocked, * stopping could cause deadlock. */ if (p->p_flag & P_PPWAIT) goto out; sigdelset(&p->p_sigctx.ps_siglist, signum); p->p_xstat = signum; if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) { /* * XXXSMP: recursive call; don't lock * the second time around. */ sched_psignal(p->p_pptr, SIGCHLD); } proc_stop(p); /* XXXSMP: recurse? */ goto out; } /* * All other (caught or default) signals * cause the process to run. */ goto runfast; /*NOTREACHED*/ case SSTOP: /* * If traced process is already stopped, * then no further action is necessary. */ if (p->p_flag & P_TRACED) goto out; /* * Kill signal always sets processes running. */ if (signum == SIGKILL) goto runfast; if (prop & SA_CONT) { /* * If SIGCONT is default (or ignored), we continue the * process but don't leave the signal in p_sigctx.ps_siglist, as * it has no further action. If SIGCONT is held, we * continue the process and leave the signal in * p_sigctx.ps_siglist. If the process catches SIGCONT, let it * handle the signal itself. If it isn't waiting on * an event, then it goes back to run state. * Otherwise, process goes back to sleep state. */ if (action == SIG_DFL) sigdelset(&p->p_sigctx.ps_siglist, signum); if (action == SIG_CATCH) goto runfast; if (p->p_wchan == 0) goto run; p->p_stat = SSLEEP; goto out; } if (prop & SA_STOP) { /* * Already stopped, don't need to stop again. * (If we did the shell could get confused.) */ sigdelset(&p->p_sigctx.ps_siglist, signum); goto out; } /* * If process is sleeping interruptibly, then simulate a * wakeup so that when it is continued, it will be made * runnable and can look at the signal. But don't make * the process runnable, leave it stopped. */ if (p->p_wchan && p->p_flag & P_SINTR) unsleep(p); goto out; #ifdef __HAVE_AST_PERPROC case SONPROC: case SRUN: case SIDL: /* * SONPROC: We're running, notice the signal when * we return back to userspace. * * SRUN, SIDL: Notice the signal when we run again * and return to back to userspace. */ signotify(p); goto out; default: /* * SDEAD, SZOMB: The signal will never be noticed. */ goto out; #else /* ! __HAVE_AST_PERPROC */ case SONPROC: /* * We're running; notice the signal. */ signotify(p); goto out; default: /* * SRUN, SIDL, SDEAD, SZOMB do nothing with the signal. * It will either never be noticed, or noticed very soon. */ goto out; #endif /* __HAVE_AST_PERPROC */ } /*NOTREACHED*/ runfast: /* * Raise priority to at least PUSER. */ if (p->p_priority > PUSER) p->p_priority = PUSER; run: setrunnable(p); /* XXXSMP: recurse? */ out: /* XXXSMP: works, but icky */ if (dolock) SCHED_UNLOCK(s); } static __inline int firstsig(const sigset_t *); static __inline int firstsig(const sigset_t *ss) { int sig; sig = ffs(ss->__bits[0]); if (sig != 0) return (sig); #if NSIG > 33 sig = ffs(ss->__bits[1]); if (sig != 0) return (sig + 32); #endif #if NSIG > 65 sig = ffs(ss->__bits[2]); if (sig != 0) return (sig + 64); #endif #if NSIG > 97 sig = ffs(ss->__bits[3]); if (sig != 0) return (sig + 96); #endif return (0); } /* * If the current process has received a signal (should be caught or cause * termination, should interrupt current syscall), return the signal number. * Stop signals with default action are processed immediately, then cleared; * they aren't returned. This is checked after each entry to the system for * a syscall or trap (though this can usually be done without calling issignal * by checking the pending signal masks in the CURSIG macro.) The normal call * sequence is * * while (signum = CURSIG(curproc)) * postsig(signum); */ int issignal(struct proc *p) { int s = 0, signum, prop; int dolock = (p->p_flag & P_SINTR) == 0, locked = !dolock; sigset_t ss; for (;;) { sigpending1(p, &ss); if (p->p_flag & P_PPWAIT) sigminusset(&stopsigmask, &ss); signum = firstsig(&ss); if (signum == 0) { /* no signal to send */ p->p_sigctx.ps_sigcheck = 0; if (locked && dolock) SCHED_LOCK(s); return (0); } /* take the signal! */ sigdelset(&p->p_sigctx.ps_siglist, signum); /* * We should see pending but ignored signals * only if P_TRACED was on when they were posted. */ if (sigismember(&p->p_sigctx.ps_sigignore, signum) && (p->p_flag & P_TRACED) == 0) continue; if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) { /* * If traced, always stop, and stay * stopped until released by the debugger. */ p->p_xstat = signum; if ((p->p_flag & P_FSTRACE) == 0) psignal1(p->p_pptr, SIGCHLD, dolock); if (dolock) SCHED_LOCK(s); proc_stop(p); mi_switch(p, NULL); SCHED_ASSERT_UNLOCKED(); if (dolock) splx(s); else dolock = 1; /* * If we are no longer being traced, or the parent * didn't give us a signal, look for more signals. */ if ((p->p_flag & P_TRACED) == 0 || p->p_xstat == 0) continue; /* * If the new signal is being masked, look for other * signals. */ signum = p->p_xstat; /* * `p->p_sigctx.ps_siglist |= mask' is done * in setrunnable(). */ if (sigismember(&p->p_sigctx.ps_sigmask, signum)) continue; /* take the signal! */ sigdelset(&p->p_sigctx.ps_siglist, signum); } prop = sigprop[signum]; /* * Decide whether the signal should be returned. * Return the signal's number, or fall through * to clear it from the pending mask. */ switch ((long)SIGACTION(p, signum).sa_handler) { case (long)SIG_DFL: /* * Don't take default actions on system processes. */ if (p->p_pid <= 1) { #ifdef DIAGNOSTIC /* * Are you sure you want to ignore SIGSEGV * in init? XXX */ printf("Process (pid %d) got signal %d\n", p->p_pid, signum); #endif break; /* == ignore */ } /* * If there is a pending stop signal to process * with default action, stop here, * then clear the signal. However, * if process is member of an orphaned * process group, ignore tty stop signals. */ if (prop & SA_STOP) { if (p->p_flag & P_TRACED || (p->p_pgrp->pg_jobc == 0 && prop & SA_TTYSTOP)) break; /* == ignore */ p->p_xstat = signum; if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) psignal1(p->p_pptr, SIGCHLD, dolock); if (dolock) SCHED_LOCK(s); proc_stop(p); mi_switch(p, NULL); SCHED_ASSERT_UNLOCKED(); if (dolock) splx(s); else dolock = 1; break; } else if (prop & SA_IGNORE) { /* * Except for SIGCONT, shouldn't get here. * Default action is to ignore; drop it. */ break; /* == ignore */ } else goto keep; /*NOTREACHED*/ case (long)SIG_IGN: /* * Masking above should prevent us ever trying * to take action on an ignored signal other * than SIGCONT, unless process is traced. */ #ifdef DEBUG_ISSIGNAL if ((prop & SA_CONT) == 0 && (p->p_flag & P_TRACED) == 0) printf("issignal\n"); #endif break; /* == ignore */ default: /* * This signal has an action, let * postsig() process it. */ goto keep; } } /* NOTREACHED */ keep: /* leave the signal for later */ sigaddset(&p->p_sigctx.ps_siglist, signum); CHECKSIGS(p); if (locked && dolock) SCHED_LOCK(s); return (signum); } /* * Put the argument process into the stopped state and notify the parent * via wakeup. Signals are handled elsewhere. The process must not be * on the run queue. */ static void proc_stop(struct proc *p) { SCHED_ASSERT_LOCKED(); p->p_stat = SSTOP; p->p_flag &= ~P_WAITED; sched_wakeup((caddr_t)p->p_pptr); } /* * Take the action for the specified signal * from the current set of pending signals. */ void postsig(int signum) { struct proc *p; struct sigacts *ps; sig_t action; u_long code; sigset_t *returnmask; p = curproc; ps = p->p_sigacts; #ifdef DIAGNOSTIC if (signum == 0) panic("postsig"); #endif KERNEL_PROC_LOCK(p); sigdelset(&p->p_sigctx.ps_siglist, signum); action = SIGACTION_PS(ps, signum).sa_handler; #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) ktrpsig(p, signum, action, p->p_sigctx.ps_flags & SAS_OLDMASK ? &p->p_sigctx.ps_oldmask : &p->p_sigctx.ps_sigmask, 0); #endif if (action == SIG_DFL) { /* * Default action, where the default is to kill * the process. (Other cases were ignored above.) */ sigexit(p, signum); /* NOTREACHED */ } else { /* * If we get here, the signal must be caught. */ #ifdef DIAGNOSTIC if (action == SIG_IGN || sigismember(&p->p_sigctx.ps_sigmask, signum)) panic("postsig action"); #endif /* * Set the new mask value and also defer further * occurences of this signal. * * Special case: user has done a sigpause. Here the * current mask is not of interest, but rather the * mask from before the sigpause is what we want * restored after the signal processing is completed. */ if (p->p_sigctx.ps_flags & SAS_OLDMASK) { returnmask = &p->p_sigctx.ps_oldmask; p->p_sigctx.ps_flags &= ~SAS_OLDMASK; } else returnmask = &p->p_sigctx.ps_sigmask; p->p_stats->p_ru.ru_nsignals++; if (p->p_sigctx.ps_sig != signum) { code = 0; } else { code = p->p_sigctx.ps_code; p->p_sigctx.ps_code = 0; p->p_sigctx.ps_sig = 0; } (*p->p_emul->e_sendsig)(signum, returnmask, code); (void) splsched(); /* XXXSMP */ sigplusset(&SIGACTION_PS(ps, signum).sa_mask, &p->p_sigctx.ps_sigmask); if (SIGACTION_PS(ps, signum).sa_flags & SA_RESETHAND) { sigdelset(&p->p_sigctx.ps_sigcatch, signum); if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) sigaddset(&p->p_sigctx.ps_sigignore, signum); SIGACTION_PS(ps, signum).sa_handler = SIG_DFL; } (void) spl0(); /* XXXSMP */ } KERNEL_PROC_UNLOCK(p); } /* * Kill the current process for stated reason. */ void killproc(struct proc *p, const char *why) { log(LOG_ERR, "pid %d was killed: %s\n", p->p_pid, why); uprintf("sorry, pid %d was killed: %s\n", p->p_pid, why); psignal(p, SIGKILL); } /* * Force the current process to exit with the specified signal, dumping core * if appropriate. We bypass the normal tests for masked and caught signals, * allowing unrecoverable failures to terminate the process without changing * signal state. Mark the accounting record with the signal termination. * If dumping core, save the signal number for the debugger. Calls exit and * does not return. */ #if defined(DEBUG) int kern_logsigexit = 1; /* not static to make public for sysctl */ #else int kern_logsigexit = 0; /* not static to make public for sysctl */ #endif static const char logcoredump[] = "pid %d (%s), uid %d: exited on signal %d (core dumped)\n"; static const char lognocoredump[] = "pid %d (%s), uid %d: exited on signal %d (core not dumped, err = %d)\n"; void sigexit(struct proc *p, int signum) { int error, exitsig; exitsig = signum; p->p_acflag |= AXSIG; if (sigprop[signum] & SA_CORE) { p->p_sigctx.ps_sig = signum; if ((error = coredump(p)) == 0) exitsig |= WCOREFLAG; if (kern_logsigexit) { /* XXX What if we ever have really large UIDs? */ int uid = p->p_cred && p->p_ucred ? (int) p->p_ucred->cr_uid : -1; if (error) log(LOG_INFO, lognocoredump, p->p_pid, p->p_comm, uid, signum, error); else log(LOG_INFO, logcoredump, p->p_pid, p->p_comm, uid, signum); } } exit1(p, W_EXITCODE(0, exitsig)); /* NOTREACHED */ } /* * Dump core, into a file named "progname.core" or "core" (depending on the * value of shortcorename), unless the process was setuid/setgid. */ int coredump(struct proc *p) { struct vnode *vp; struct vmspace *vm; struct ucred *cred; struct nameidata nd; struct vattr vattr; int error, error1; char name[MAXPATHLEN]; vm = p->p_vmspace; cred = p->p_cred->pc_ucred; /* * Make sure the process has not set-id, to prevent data leaks. */ if (p->p_flag & P_SUGID) return (EPERM); /* * Refuse to core if the data + stack + user size is larger than * the core dump limit. XXX THIS IS WRONG, because of mapped * data. */ if (USPACE + ctob(vm->vm_dsize + vm->vm_ssize) >= p->p_rlimit[RLIMIT_CORE].rlim_cur) return (EFBIG); /* better error code? */ /* * The core dump will go in the current working directory. Make * sure that the directory is still there and that the mount flags * allow us to write core dumps there. */ vp = p->p_cwdi->cwdi_cdir; if (vp->v_mount == NULL || (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0) return (EPERM); error = build_corename(p, name); if (error) return error; NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p); error = vn_open(&nd, O_CREAT | O_NOFOLLOW | FWRITE, S_IRUSR | S_IWUSR); if (error) return (error); vp = nd.ni_vp; /* Don't dump to non-regular files or files with links. */ if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred, p) || vattr.va_nlink != 1) { error = EINVAL; goto out; } VATTR_NULL(&vattr); vattr.va_size = 0; VOP_LEASE(vp, p, cred, LEASE_WRITE); VOP_SETATTR(vp, &vattr, cred, p); p->p_acflag |= ACORE; /* Now dump the actual core file. */ error = (*p->p_execsw->es_coredump)(p, vp, cred); out: VOP_UNLOCK(vp, 0); error1 = vn_close(vp, FWRITE, cred, p); if (error == 0) error = error1; return (error); } /* * Nonexistent system call-- signal process (may want to handle it). * Flag error in case process won't see signal immediately (blocked or ignored). */ /* ARGSUSED */ int sys_nosys(struct proc *p, void *v, register_t *retval) { psignal(p, SIGSYS); return (ENOSYS); } static int build_corename(struct proc *p, char dst[MAXPATHLEN]) { const char *s; char *d, *end; int i; for (s = p->p_limit->pl_corename, d = dst, end = d + MAXPATHLEN; *s != '\0'; s++) { if (*s == '%') { switch (*(s + 1)) { case 'n': i = snprintf(d, end - d, "%s", p->p_comm); break; case 'p': i = snprintf(d, end - d, "%d", p->p_pid); break; case 'u': i = snprintf(d, end - d, "%s", p->p_pgrp->pg_session->s_login); break; case 't': i = snprintf(d, end - d, "%ld", p->p_stats->p_start.tv_sec); break; default: goto copy; } d += i; s++; } else { copy: *d = *s; d++; } if (d >= end) return (ENAMETOOLONG); } *d = '\0'; return (0); } /* * Returns true if signal is ignored or masked for passed process. */ int sigismasked(struct proc *p, int sig) { return (sigismember(&p->p_sigctx.ps_sigignore, sig) || sigismember(&p->p_sigctx.ps_sigmask, sig)); } static int filt_sigattach(struct knote *kn) { struct proc *p = curproc; kn->kn_ptr.p_proc = p; kn->kn_flags |= EV_CLEAR; /* automatically set */ SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); return (0); } static void filt_sigdetach(struct knote *kn) { struct proc *p = kn->kn_ptr.p_proc; SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); } /* * signal knotes are shared with proc knotes, so we apply a mask to * the hint in order to differentiate them from process hints. This * could be avoided by using a signal-specific knote list, but probably * isn't worth the trouble. */ static int filt_signal(struct knote *kn, long hint) { if (hint & NOTE_SIGNAL) { hint &= ~NOTE_SIGNAL; if (kn->kn_id == hint) kn->kn_data++; } return (kn->kn_data != 0); } const struct filterops sig_filtops = { 0, filt_sigattach, filt_sigdetach, filt_signal };