/* $NetBSD: kern_sig.c,v 1.93 1999/08/31 12:30:35 bouyer 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 "opt_ktrace.h" #include "opt_compat_sunos.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 #include /* for coredump */ #include void stop __P((struct proc *p)); void killproc __P((struct proc *, char *)); 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() { pool_init(&sigacts_pool, sizeof(struct sigacts), 0, 0, 0, "sigapl", 0, pool_page_alloc_nointr, pool_page_free_nointr, M_SUBPROC); } /* * Create an initial sigacts structure, using the same signal state * as p. */ struct sigacts * sigactsinit(p) struct proc *p; { struct sigacts *ps; ps = pool_get(&sigacts_pool, PR_WAITOK); memcpy(ps, p->p_sigacts, sizeof(struct sigacts)); ps->ps_refcnt = 1; return (ps); } /* * Make p2 share p1's sigacts. */ void sigactsshare(p1, p2) struct proc *p1, *p2; { p2->p_sigacts = p1->p_sigacts; p1->p_sigacts->ps_refcnt++; } /* * Make this process not share its sigacts, maintaining all * signal state. */ void sigactsunshare(p) struct proc *p; { struct sigacts *newps; if (p->p_sigacts->ps_refcnt == 1) return; newps = sigactsinit(p); sigactsfree(p); p->p_sigacts = newps; } /* * Release a sigacts structure. */ void sigactsfree(p) struct proc *p; { struct sigacts *ps = p->p_sigacts; if (--ps->ps_refcnt > 0) return; p->p_sigacts = NULL; pool_put(&sigacts_pool, ps); } int sigaction1(p, signum, nsa, osa) struct proc *p; int signum; const struct sigaction *nsa; struct sigaction *osa; { register struct sigacts *ps = p->p_sigacts; int prop; if (signum <= 0 || signum >= NSIG) return (EINVAL); if (osa) *osa = ps->ps_sigact[signum]; if (nsa) { if (nsa->sa_flags & ~SA_ALLBITS) return (EINVAL); prop = sigprop[signum]; if (prop & SA_CANTMASK) return (EINVAL); (void) splhigh(); ps->ps_sigact[signum] = *nsa; sigminusset(&sigcantmask, &ps->ps_sigact[signum].sa_mask); if ((prop & SA_NORESET) != 0) ps->ps_sigact[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(&ps->ps_sigact[signum].sa_mask, signum); else sigdelset(&ps->ps_sigact[signum].sa_mask, signum); /* * Set bit in p_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_sigignore, * as we have to restart the process. */ if (nsa->sa_handler == SIG_IGN || (nsa->sa_handler == SIG_DFL && (prop & SA_IGNORE) != 0)) { sigdelset(&p->p_siglist, signum); /* never to be seen again */ if (signum != SIGCONT) sigaddset(&p->p_sigignore, signum); /* easier in psignal */ sigdelset(&p->p_sigcatch, signum); } else { sigdelset(&p->p_sigignore, signum); if (nsa->sa_handler == SIG_DFL) sigdelset(&p->p_sigcatch, signum); else sigaddset(&p->p_sigcatch, signum); } (void) spl0(); } return (0); } /* ARGSUSED */ int sys___sigaction14(p, v, retval) struct proc *p; void *v; register_t *retval; { register 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); 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(p) struct proc *p; { register struct sigacts *ps = p->p_sigacts; register int signum; int prop; 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_sigignore, signum); sigemptyset(&ps->ps_sigact[signum].sa_mask); ps->ps_sigact[signum].sa_flags = SA_RESTART; } sigemptyset(&p->p_sigcatch); p->p_flag &= ~P_NOCLDSTOP; /* * Reset stack state to the user stack. */ ps->ps_sigstk.ss_flags = SS_DISABLE; ps->ps_sigstk.ss_size = 0; ps->ps_sigstk.ss_sp = 0; /* One reference. */ ps->ps_refcnt = 1; } /* * Reset signals for an exec of the specified process. */ void execsigs(p) register struct proc *p; { register struct sigacts *ps = p->p_sigacts; register int signum; int prop; /* * Reset caught signals. Held signals remain held * through p_sigmask (unless they were caught, * and are now ignored by default). */ for (signum = 1; signum < NSIG; signum++) { if (sigismember(&p->p_sigcatch, signum)) { prop = sigprop[signum]; if (prop & SA_IGNORE) { if ((prop & SA_CONT) == 0) sigaddset(&p->p_sigignore, signum); sigdelset(&p->p_siglist, signum); } ps->ps_sigact[signum].sa_handler = SIG_DFL; } sigemptyset(&ps->ps_sigact[signum].sa_mask); ps->ps_sigact[signum].sa_flags = SA_RESTART; } sigemptyset(&p->p_sigcatch); p->p_flag &= ~P_NOCLDSTOP; /* * Reset stack state to the user stack. */ ps->ps_sigstk.ss_flags = SS_DISABLE; ps->ps_sigstk.ss_size = 0; ps->ps_sigstk.ss_sp = 0; } int sigprocmask1(p, how, nss, oss) struct proc *p; int how; const sigset_t *nss; sigset_t *oss; { if (oss) *oss = p->p_sigmask; if (nss) { (void)splhigh(); switch (how) { case SIG_BLOCK: sigplusset(nss, &p->p_sigmask); break; case SIG_UNBLOCK: sigminusset(nss, &p->p_sigmask); p->p_sigcheck = 1; break; case SIG_SETMASK: p->p_sigmask = *nss; p->p_sigcheck = 1; break; default: (void)spl0(); return (EINVAL); } sigminusset(&sigcantmask, &p->p_sigmask); (void)spl0(); } 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(p, v, retval) register 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(p, ss) struct proc *p; sigset_t *ss; { *ss = p->p_siglist; sigminusset(&p->p_sigmask, ss); } /* ARGSUSED */ int sys___sigpending14(p, v, retval) struct proc *p; void *v; register_t *retval; { register 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(p, ss) struct proc *p; const sigset_t *ss; { register struct sigacts *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 sigacts structure * to indicate this. */ ps->ps_oldmask = p->p_sigmask; ps->ps_flags |= SAS_OLDMASK; (void) splhigh(); p->p_sigmask = *ss; p->p_sigcheck = 1; sigminusset(&sigcantmask, &p->p_sigmask); (void) spl0(); } 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(p, v, retval) register 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(p, nss, oss) struct proc *p; const struct sigaltstack *nss; struct sigaltstack *oss; { register struct sigacts *ps = p->p_sigacts; if (oss) *oss = ps->ps_sigstk; if (nss) { if (nss->ss_flags & ~SS_ALLBITS) return (EINVAL); if (nss->ss_flags & SS_DISABLE) { if (ps->ps_sigstk.ss_flags & SS_ONSTACK) return (EINVAL); } else { if (nss->ss_size < MINSIGSTKSZ) return (ENOMEM); } ps->ps_sigstk = *nss; } return (0); } /* ARGSUSED */ int sys___sigaltstack14(p, v, retval) struct proc *p; void *v; register_t *retval; { register 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(cp, v, retval) register struct proc *cp; void *v; register_t *retval; { register struct sys_kill_args /* { syscallarg(int) pid; syscallarg(int) signum; } */ *uap = v; register struct proc *p; register struct pcred *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(cp, signum, pgid, all) register struct proc *cp; int signum, pgid, all; { register struct proc *p; register struct pcred *pc = cp->p_cred; struct pgrp *pgrp; int nfound = 0; if (all) { /* * broadcast */ proclist_lock_read(); for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 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); } for (p = pgrp->pg_members.lh_first; p != 0; p = p->p_pglist.le_next) { 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(pgid, signum) int pgid, 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(pgrp, signum, checkctty) struct pgrp *pgrp; int signum, checkctty; { register struct proc *p; if (pgrp) for (p = pgrp->pg_members.lh_first; p != 0; p = p->p_pglist.le_next) 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(p, signum, code) struct proc *p; register int signum; u_long code; { register struct sigacts *ps = p->p_sigacts; if ((p->p_flag & P_TRACED) == 0 && sigismember(&p->p_sigcatch, signum) && !sigismember(&p->p_sigmask, signum)) { p->p_stats->p_ru.ru_nsignals++; #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) ktrpsig(p->p_tracep, signum, ps->ps_sigact[signum].sa_handler, &p->p_sigmask, code); #endif (*p->p_emul->e_sendsig)(ps->ps_sigact[signum].sa_handler, signum, &p->p_sigmask, code); (void) splhigh(); sigplusset(&ps->ps_sigact[signum].sa_mask, &p->p_sigmask); if (ps->ps_sigact[signum].sa_flags & SA_RESETHAND) { sigdelset(&p->p_sigcatch, signum); if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) sigaddset(&p->p_sigignore, signum); ps->ps_sigact[signum].sa_handler = SIG_DFL; } (void) spl0(); } else { ps->ps_code = code; /* XXX for core dump/debugger */ ps->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. */ void psignal(p, signum) register struct proc *p; register int signum; { register int s, prop; register sig_t action; #ifdef DIAGNOSTIC if (signum <= 0 || signum >= NSIG) panic("psignal signal number"); #endif 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_sigignore, * and if it is set to SIG_IGN, * action will be SIG_DFL here.) */ if (sigismember(&p->p_sigignore, signum)) return; if (sigismember(&p->p_sigmask, signum)) action = SIG_HOLD; else if (sigismember(&p->p_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_siglist); if (prop & SA_STOP) sigminusset(&contsigmask, &p->p_siglist); sigaddset(&p->p_siglist, signum); p->p_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; s = splhigh(); 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_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_siglist, signum); p->p_xstat = signum; if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) psignal(p->p_pptr, SIGCHLD); stop(p); 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_siglist, as * it has no further action. If SIGCONT is held, we * continue the process and leave the signal in * p_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_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_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; default: /* * SRUN, SIDL, SDEAD, SZOMB do nothing with the signal, * other than kicking ourselves if we are running. * It will either never be noticed, or noticed very soon. */ if (p == curproc) signotify(p); goto out; } /*NOTREACHED*/ runfast: /* * Raise priority to at least PUSER. */ if (p->p_priority > PUSER) p->p_priority = PUSER; run: setrunnable(p); out: splx(s); } static __inline int firstsig __P((const sigset_t *)); static __inline int firstsig(ss) 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(p) register struct proc *p; { register int signum, prop; 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_sigcheck = 0; return (0); } sigdelset(&p->p_siglist, signum); /* take the signal! */ /* * We should see pending but ignored signals * only if P_TRACED was on when they were posted. */ if (sigismember(&p->p_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) psignal(p->p_pptr, SIGCHLD); do { stop(p); mi_switch(); } while (!trace_req(p) && p->p_flag & P_TRACED); /* * 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_siglist |= mask' is done in setrunnable(). */ if (sigismember(&p->p_sigmask, signum)) continue; sigdelset(&p->p_siglist, signum); /* take the signal! */ } 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)p->p_sigacts->ps_sigact[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) psignal(p->p_pptr, SIGCHLD); stop(p); mi_switch(); 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. */ if ((prop & SA_CONT) == 0 && (p->p_flag & P_TRACED) == 0) printf("issignal\n"); break; /* == ignore */ default: /* * This signal has an action, let * postsig() process it. */ goto keep; } } /* NOTREACHED */ keep: sigaddset(&p->p_siglist, signum); /* leave the signal for later */ p->p_sigcheck = 1; 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. */ void stop(p) register struct proc *p; { p->p_stat = SSTOP; p->p_flag &= ~P_WAITED; wakeup((caddr_t)p->p_pptr); } /* * Take the action for the specified signal * from the current set of pending signals. */ void postsig(signum) register int signum; { register struct proc *p = curproc; register struct sigacts *ps = p->p_sigacts; register sig_t action; u_long code; sigset_t *returnmask; #ifdef DIAGNOSTIC if (signum == 0) panic("postsig"); #endif sigdelset(&p->p_siglist, signum); action = ps->ps_sigact[signum].sa_handler; #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) ktrpsig(p->p_tracep, signum, action, ps->ps_flags & SAS_OLDMASK ? &ps->ps_oldmask : &p->p_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_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 (ps->ps_flags & SAS_OLDMASK) { returnmask = &ps->ps_oldmask; ps->ps_flags &= ~SAS_OLDMASK; } else returnmask = &p->p_sigmask; p->p_stats->p_ru.ru_nsignals++; if (ps->ps_sig != signum) { code = 0; } else { code = ps->ps_code; ps->ps_code = 0; ps->ps_sig = 0; } (*p->p_emul->e_sendsig)(action, signum, returnmask, code); (void) splhigh(); sigplusset(&ps->ps_sigact[signum].sa_mask, &p->p_sigmask); if (ps->ps_sigact[signum].sa_flags & SA_RESETHAND) { sigdelset(&p->p_sigcatch, signum); if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) sigaddset(&p->p_sigignore, signum); ps->ps_sigact[signum].sa_handler = SIG_DFL; } (void) spl0(); } } /* * Kill the current process for stated reason. */ void killproc(p, why) struct proc *p; 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. */ void sigexit(p, signum) register struct proc *p; int signum; { p->p_acflag |= AXSIG; if (sigprop[signum] & SA_CORE) { p->p_sigacts->ps_sig = signum; if (coredump(p) == 0) signum |= WCOREFLAG; } exit1(p, W_EXITCODE(0, signum)); /* 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(p) register struct proc *p; { register struct vnode *vp; register struct vmspace *vm = p->p_vmspace; register struct ucred *cred = p->p_cred->pc_ucred; struct nameidata nd; struct vattr vattr; int error, error1; char name[MAXCOMLEN+6]; /* progname.core */ struct core core; extern int shortcorename; /* * 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); if (shortcorename) sprintf(name, "core"); else sprintf(name, "%s.core", p->p_comm); NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p); error = vn_open(&nd, O_CREAT | FWRITE | FNOSYMLINK, 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; #if 0 /* * XXX * It would be nice if we at least dumped the signal state (and made it * available at run time to the debugger, as well), but this code * hasn't actually had any effect for a long time, since we don't dump * the user area. For now, it's dead. */ memcpy(&p->p_addr->u_kproc.kp_proc, p, sizeof(struct proc)); fill_eproc(p, &p->p_addr->u_kproc.kp_eproc); #endif core.c_midmag = 0; strncpy(core.c_name, p->p_comm, MAXCOMLEN); core.c_nseg = 0; core.c_signo = p->p_sigacts->ps_sig; core.c_ucode = p->p_sigacts->ps_code; core.c_cpusize = 0; core.c_tsize = (u_long)ctob(vm->vm_tsize); core.c_dsize = (u_long)ctob(vm->vm_dsize); core.c_ssize = (u_long)round_page(ctob(vm->vm_ssize)); error = cpu_coredump(p, vp, cred, &core); if (error) goto out; if (core.c_midmag == 0) { /* XXX * cpu_coredump() didn't bother to set the magic; assume * this is a request to do a traditional dump. cpu_coredump() * is still responsible for setting sensible values in * the core header. */ if (core.c_cpusize == 0) core.c_cpusize = USPACE; /* Just in case */ error = vn_rdwr(UIO_WRITE, vp, vm->vm_daddr, (int)core.c_dsize, (off_t)core.c_cpusize, UIO_USERSPACE, IO_NODELOCKED|IO_UNIT, cred, NULL, p); if (error) goto out; error = vn_rdwr(UIO_WRITE, vp, (caddr_t) trunc_page(USRSTACK - ctob(vm->vm_ssize)), core.c_ssize, (off_t)(core.c_cpusize + core.c_dsize), UIO_USERSPACE, IO_NODELOCKED|IO_UNIT, cred, NULL, p); } else { /* * uvm_coredump() spits out all appropriate segments. * All that's left to do is to write the core header. */ error = uvm_coredump(p, vp, cred, &core); if (error) goto out; error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&core, (int)core.c_hdrsize, (off_t)0, UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, NULL, p); } 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(p, v, retval) struct proc *p; void *v; register_t *retval; { psignal(p, SIGSYS); return (ENOSYS); }