/* * 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 8.7 (Berkeley) 4/18/94 * $Id: kern_sig.c,v 1.60 1999/08/16 18:13:38 billf Exp $ */ #include "opt_compat.h" #include "opt_ktrace.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 #ifdef SMP #include #endif static int killpg1 __P((struct proc *cp, int signum, int pgid, int all)); static void setsigvec __P((struct proc *p, int signum, struct sigaction *sa)); static void stop __P((struct proc *)); static int kern_logsigexit = 1; SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, &kern_logsigexit, 0, "Log processes quitting on abnormal signals to syslog(3)"); /* * Can process p, with pcred pc, send the signal signum to process q? */ #define CANSIGNAL(p, pc, q, signum) \ (PRISON_CHECK(p, q) && ((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))) /* * Policy -- Can real uid ruid with ucred uc send a signal to process q? */ #define CANSIGIO(ruid, uc, q) \ ((uc)->cr_uid == 0 || \ (ruid) == (q)->p_cred->p_ruid || \ (uc)->cr_uid == (q)->p_cred->p_ruid || \ (ruid) == (q)->p_ucred->cr_uid || \ (uc)->cr_uid == (q)->p_ucred->cr_uid) int sugid_coredump; SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); #ifndef _SYS_SYSPROTO_H_ struct sigaction_args { int signum; struct sigaction *nsa; struct sigaction *osa; }; #endif /* ARGSUSED */ int sigaction(p, uap) struct proc *p; register struct sigaction_args *uap; { struct sigaction vec; register struct sigaction *sa; register struct sigacts *ps = p->p_sigacts; register int signum; int bit, error; signum = uap->signum; if (signum <= 0 || signum >= NSIG) return (EINVAL); sa = &vec; if (uap->osa) { bit = sigmask(signum); if ((ps->ps_siginfo & bit) != 0) sa->sa_sigaction = (__siginfohandler_t *)ps->ps_sigact[signum]; else sa->sa_handler = ps->ps_sigact[signum]; sa->sa_mask = ps->ps_catchmask[signum]; sa->sa_flags = 0; if ((ps->ps_sigonstack & bit) != 0) sa->sa_flags |= SA_ONSTACK; if ((ps->ps_sigintr & bit) == 0) sa->sa_flags |= SA_RESTART; if ((ps->ps_sigreset & bit) != 0) sa->sa_flags |= SA_RESETHAND; if ((ps->ps_signodefer & bit) != 0) sa->sa_flags |= SA_NODEFER; if ((ps->ps_siginfo & bit) != 0) sa->sa_flags |= SA_SIGINFO; if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDSTOP) sa->sa_flags |= SA_NOCLDSTOP; if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDWAIT) sa->sa_flags |= SA_NOCLDWAIT; if ((error = copyout((caddr_t)sa, (caddr_t)uap->osa, sizeof (vec)))) return (error); } if (uap->nsa) { if ((error = copyin((caddr_t)uap->nsa, (caddr_t)sa, sizeof (vec)))) return (error); if ((signum == SIGKILL || signum == SIGSTOP) && sa->sa_handler != SIG_DFL) return (EINVAL); setsigvec(p, signum, sa); } return (0); } static void setsigvec(p, signum, sa) register struct proc *p; int signum; register struct sigaction *sa; { register struct sigacts *ps = p->p_sigacts; register int bit; bit = sigmask(signum); /* * Change setting atomically. */ (void) splhigh(); ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; if (sa->sa_flags & SA_SIGINFO) { ps->ps_sigact[signum] = sa->sa_handler; ps->ps_siginfo |= bit; } else { ps->ps_sigact[signum] = (__sighandler_t *)sa->sa_sigaction; ps->ps_siginfo &= ~bit; } if ((sa->sa_flags & SA_RESTART) == 0) ps->ps_sigintr |= bit; else ps->ps_sigintr &= ~bit; if (sa->sa_flags & SA_ONSTACK) ps->ps_sigonstack |= bit; else ps->ps_sigonstack &= ~bit; if (sa->sa_flags & SA_RESETHAND) ps->ps_sigreset |= bit; else ps->ps_sigreset &= ~bit; if (sa->sa_flags & SA_NODEFER) ps->ps_signodefer |= bit; else ps->ps_signodefer &= ~bit; #ifdef COMPAT_SUNOS if (sa->sa_flags & SA_USERTRAMP) ps->ps_usertramp |= bit; else ps->ps_usertramp &= ~bit; #endif if (signum == SIGCHLD) { if (sa->sa_flags & SA_NOCLDSTOP) p->p_procsig->ps_flag |= P_NOCLDSTOP; else p->p_procsig->ps_flag &= ~P_NOCLDSTOP; if (sa->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_procsig->ps_flag &= ~P_NOCLDWAIT; else p->p_procsig->ps_flag |= P_NOCLDWAIT; } else p->p_procsig->ps_flag &= ~P_NOCLDWAIT; } /* * 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 (ps->ps_sigact[signum] == SIG_IGN || (sigprop[signum] & SA_IGNORE && ps->ps_sigact[signum] == SIG_DFL)) { p->p_siglist &= ~bit; /* never to be seen again */ if (signum != SIGCONT) p->p_sigignore |= bit; /* easier in psignal */ p->p_sigcatch &= ~bit; } else { p->p_sigignore &= ~bit; if (ps->ps_sigact[signum] == SIG_DFL) p->p_sigcatch &= ~bit; else p->p_sigcatch |= bit; } (void) spl0(); } /* * Initialize signal state for process 0; * set to ignore signals that are ignored by default. */ void siginit(p) struct proc *p; { register int i; for (i = 0; i < NSIG; i++) if (sigprop[i] & SA_IGNORE && i != SIGCONT) p->p_sigignore |= sigmask(i); } /* * 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 nc, mask; /* * Reset caught signals. Held signals remain held * through p_sigmask (unless they were caught, * and are now ignored by default). */ while (p->p_sigcatch) { nc = ffs((long)p->p_sigcatch); mask = sigmask(nc); p->p_sigcatch &= ~mask; if (sigprop[nc] & SA_IGNORE) { if (nc != SIGCONT) p->p_sigignore |= mask; p->p_siglist &= ~mask; } ps->ps_sigact[nc] = SIG_DFL; } /* * Reset stack state to the user stack. * Clear set of signals caught on the signal stack. */ ps->ps_sigstk.ss_flags = SS_DISABLE; ps->ps_sigstk.ss_size = 0; ps->ps_sigstk.ss_sp = 0; ps->ps_flags = 0; /* * Reset no zombies if child dies flag as Solaris does. */ p->p_procsig->ps_flag &= ~P_NOCLDWAIT; } /* * Manipulate signal mask. * Note that we receive new mask, not pointer, * and return old mask as return value; * the library stub does the rest. */ #ifndef _SYS_SYSPROTO_H_ struct sigprocmask_args { int how; sigset_t mask; }; #endif int sigprocmask(p, uap) register struct proc *p; struct sigprocmask_args *uap; { int error = 0; p->p_retval[0] = p->p_sigmask; (void) splhigh(); switch (uap->how) { case SIG_BLOCK: p->p_sigmask |= uap->mask &~ sigcantmask; break; case SIG_UNBLOCK: p->p_sigmask &= ~uap->mask; break; case SIG_SETMASK: p->p_sigmask = uap->mask &~ sigcantmask; break; default: error = EINVAL; break; } (void) spl0(); return (error); } #ifndef _SYS_SYSPROTO_H_ struct sigpending_args { int dummy; }; #endif /* ARGSUSED */ int sigpending(p, uap) struct proc *p; struct sigpending_args *uap; { p->p_retval[0] = p->p_siglist; return (0); } #if defined(COMPAT_43) || defined(COMPAT_SUNOS) /* * Generalized interface signal handler, 4.3-compatible. */ #ifndef _SYS_SYSPROTO_H_ struct osigvec_args { int signum; struct sigvec *nsv; struct sigvec *osv; }; #endif /* ARGSUSED */ int osigvec(p, uap) struct proc *p; register struct osigvec_args *uap; { struct sigvec vec; register struct sigacts *ps = p->p_sigacts; register struct sigvec *sv; register int signum; int bit, error; signum = uap->signum; if (signum <= 0 || signum >= NSIG) return (EINVAL); sv = &vec; if (uap->osv) { *(sig_t *)&sv->sv_handler = ps->ps_sigact[signum]; sv->sv_mask = ps->ps_catchmask[signum]; bit = sigmask(signum); sv->sv_flags = 0; if ((ps->ps_sigonstack & bit) != 0) sv->sv_flags |= SV_ONSTACK; if ((ps->ps_sigintr & bit) != 0) sv->sv_flags |= SV_INTERRUPT; if ((ps->ps_sigreset & bit) != 0) sv->sv_flags |= SV_RESETHAND; if ((ps->ps_signodefer & bit) != 0) sv->sv_flags |= SV_NODEFER; if ((ps->ps_siginfo & bit) != 0) sv->sv_flags |= SV_SIGINFO; #ifndef COMPAT_SUNOS if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDSTOP) sv->sv_flags |= SV_NOCLDSTOP; #endif if ((error = copyout((caddr_t)sv, (caddr_t)uap->osv, sizeof (vec)))) return (error); } if (uap->nsv) { if ((error = copyin((caddr_t)uap->nsv, (caddr_t)sv, sizeof (vec)))) return (error); if ((signum == SIGKILL || signum == SIGSTOP) && sv->sv_handler != SIG_DFL) return (EINVAL); #ifdef COMPAT_SUNOS sv->sv_flags |= SA_USERTRAMP; #endif sv->sv_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */ setsigvec(p, signum, (struct sigaction *)sv); } return (0); } #ifndef _SYS_SYSPROTO_H_ struct osigblock_args { int mask; }; #endif int osigblock(p, uap) register struct proc *p; struct osigblock_args *uap; { (void) splhigh(); p->p_retval[0] = p->p_sigmask; p->p_sigmask |= uap->mask &~ sigcantmask; (void) spl0(); return (0); } #ifndef _SYS_SYSPROTO_H_ struct osigsetmask_args { int mask; }; #endif int osigsetmask(p, uap) struct proc *p; struct osigsetmask_args *uap; { (void) splhigh(); p->p_retval[0] = p->p_sigmask; p->p_sigmask = uap->mask &~ sigcantmask; (void) spl0(); return (0); } #endif /* COMPAT_43 || COMPAT_SUNOS */ /* * 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. */ #ifndef _SYS_SYSPROTO_H_ struct sigsuspend_args { sigset_t mask; }; #endif /* ARGSUSED */ int sigsuspend(p, uap) register struct proc *p; struct sigsuspend_args *uap; { register struct sigacts *ps = p->p_sigacts; /* * 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. */ p->p_oldsigmask = p->p_sigmask; p->p_sigmask = uap->mask &~ sigcantmask; while (tsleep((caddr_t) ps, PPAUSE|PCATCH, "pause", 0) == 0) /* void */; /* always return EINTR rather than ERESTART... */ return (EINTR); } #if defined(COMPAT_43) || defined(COMPAT_SUNOS) #ifndef _SYS_SYSPROTO_H_ struct osigstack_args { struct sigstack *nss; struct sigstack *oss; }; #endif /* ARGSUSED */ int osigstack(p, uap) struct proc *p; register struct osigstack_args *uap; { struct sigstack ss; struct sigacts *psp; int error = 0; psp = p->p_sigacts; ss.ss_sp = psp->ps_sigstk.ss_sp; ss.ss_onstack = psp->ps_sigstk.ss_flags & SS_ONSTACK; if (uap->oss && (error = copyout((caddr_t)&ss, (caddr_t)uap->oss, sizeof (struct sigstack)))) return (error); if (uap->nss && (error = copyin((caddr_t)uap->nss, (caddr_t)&ss, sizeof (ss))) == 0) { psp->ps_sigstk.ss_sp = ss.ss_sp; psp->ps_sigstk.ss_size = 0; psp->ps_sigstk.ss_flags |= ss.ss_onstack & SS_ONSTACK; psp->ps_flags |= SAS_ALTSTACK; } return (error); } #endif /* COMPAT_43 || COMPAT_SUNOS */ #ifndef _SYS_SYSPROTO_H_ struct sigaltstack_args { struct sigaltstack *nss; struct sigaltstack *oss; }; #endif /* ARGSUSED */ int sigaltstack(p, uap) struct proc *p; register struct sigaltstack_args *uap; { struct sigacts *psp; struct sigaltstack ss; int error; psp = p->p_sigacts; if ((psp->ps_flags & SAS_ALTSTACK) == 0) psp->ps_sigstk.ss_flags |= SS_DISABLE; if (uap->oss && (error = copyout((caddr_t)&psp->ps_sigstk, (caddr_t)uap->oss, sizeof (struct sigaltstack)))) return (error); if (uap->nss == 0) return (0); if ((error = copyin((caddr_t)uap->nss, (caddr_t)&ss, sizeof (ss)))) return (error); if (ss.ss_flags & SS_DISABLE) { if (psp->ps_sigstk.ss_flags & SS_ONSTACK) return (EINVAL); psp->ps_flags &= ~SAS_ALTSTACK; psp->ps_sigstk.ss_flags = ss.ss_flags; return (0); } if (ss.ss_size < MINSIGSTKSZ) return (ENOMEM); psp->ps_flags |= SAS_ALTSTACK; psp->ps_sigstk= ss; return (0); } /* * 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 */ 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); } 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 || p->p_stat == SZOMB || !CANSIGNAL(cp, pc, p, signum)) continue; nfound++; if (signum) psignal(p, signum); } } return (nfound ? 0 : ESRCH); } #ifndef _SYS_SYSPROTO_H_ struct kill_args { int pid; int signum; }; #endif /* ARGSUSED */ int kill(cp, uap) register struct proc *cp; register struct kill_args *uap; { register struct proc *p; register struct pcred *pc = cp->p_cred; if ((u_int)uap->signum >= NSIG) return (EINVAL); if (uap->pid > 0) { /* kill single process */ if ((p = pfind(uap->pid)) == NULL) return (ESRCH); if (!CANSIGNAL(cp, pc, p, uap->signum)) return (EPERM); if (uap->signum) psignal(p, uap->signum); return (0); } switch (uap->pid) { case -1: /* broadcast signal */ return (killpg1(cp, uap->signum, 0, 1)); case 0: /* signal own process group */ return (killpg1(cp, uap->signum, 0, 0)); default: /* negative explicit process group */ return (killpg1(cp, uap->signum, -uap->pid, 0)); } /* NOTREACHED */ } #if defined(COMPAT_43) || defined(COMPAT_SUNOS) #ifndef _SYS_SYSPROTO_H_ struct okillpg_args { int pgid; int signum; }; #endif /* ARGSUSED */ int okillpg(p, uap) struct proc *p; register struct okillpg_args *uap; { if ((u_int)uap->signum >= NSIG) return (EINVAL); return (killpg1(p, uap->signum, uap->pgid, 0)); } #endif /* COMPAT_43 || COMPAT_SUNOS */ /* * 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; int mask; mask = sigmask(signum); if ((p->p_flag & P_TRACED) == 0 && (p->p_sigcatch & mask) != 0 && (p->p_sigmask & mask) == 0) { p->p_stats->p_ru.ru_nsignals++; #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) ktrpsig(p->p_tracep, signum, ps->ps_sigact[signum], p->p_sigmask, code); #endif (*p->p_sysent->sv_sendsig)(ps->ps_sigact[signum], signum, p->p_sigmask, code); p->p_sigmask |= ps->ps_catchmask[signum] | (mask & ~ps->ps_signodefer); if ((ps->ps_sigreset & mask) != 0) { /* * See setsigvec() for origin of this code. */ p->p_sigcatch &= ~mask; if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) p->p_sigignore |= mask; ps->ps_sigact[signum] = SIG_DFL; } } else { p->p_code = code; /* XXX for core dump/debugger */ p->p_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; int mask; if ((u_int)signum >= NSIG || signum == 0) { printf("psignal: signum %d\n", signum); panic("psignal signal number"); } mask = sigmask(signum); prop = sigprop[signum]; /* * If proc is traced, always give parent a chance; * if signal event is tracked by procfs, give *that* * a chance, as well. */ if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) 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 ((p->p_sigignore & mask) || (p->p_flag & P_WEXIT)) return; if (p->p_sigmask & mask) action = SIG_HOLD; else if (p->p_sigcatch & mask) action = SIG_CATCH; else action = SIG_DFL; } if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && (p->p_flag & P_TRACED) == 0) p->p_nice = NZERO; if (prop & SA_CONT) p->p_siglist &= ~stopsigmask; if (prop & SA_STOP) { /* * 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 && action == SIG_DFL) return; p->p_siglist &= ~contsigmask; } p->p_siglist |= mask; /* * 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) { p->p_siglist &= ~mask; goto out; } /* * When a sleeping process receives a stop * signal, process immediately if possible. * All other (caught or default) signals * cause the process to run. */ if (prop & SA_STOP) { if (action != SIG_DFL) goto runfast; /* * If a child holding parent blocked, * stopping could cause deadlock. */ if (p->p_flag & P_PPWAIT) goto out; p->p_siglist &= ~mask; p->p_xstat = signum; if ((p->p_pptr->p_procsig->ps_flag & P_NOCLDSTOP) == 0) psignal(p->p_pptr, SIGCHLD); stop(p); goto out; } else 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) p->p_siglist &= ~mask; 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.) */ p->p_siglist &= ~mask; /* take it away */ 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, 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); #ifdef SMP else if (p->p_stat == SRUN) forward_signal(p); #endif 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); } /* * 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, mask, prop; for (;;) { int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); mask = p->p_siglist & ~p->p_sigmask; if (p->p_flag & P_PPWAIT) mask &= ~stopsigmask; if (mask == 0) /* no signal to send */ return (0); signum = ffs((long)mask); mask = sigmask(signum); prop = sigprop[signum]; STOPEVENT(p, S_SIG, signum); /* * We should see pending but ignored signals * only if P_TRACED was on when they were posted. */ if ((mask & p->p_sigignore) && (traced == 0)) { p->p_siglist &= ~mask; continue; } if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) { /* * If traced, always stop, and stay * stopped until released by the parent. */ p->p_xstat = signum; psignal(p->p_pptr, SIGCHLD); do { stop(p); mi_switch(); } while (!trace_req(p) && p->p_flag & P_TRACED); /* * If the traced bit got turned off, go back up * to the top to rescan signals. This ensures * that p_sig* and ps_sigact are consistent. */ if ((p->p_flag & P_TRACED) == 0) continue; /* * If parent wants us to take the signal, * then it will leave it in p->p_xstat; * otherwise we just look for signals again. */ p->p_siglist &= ~mask; /* clear the old signal */ signum = p->p_xstat; if (signum == 0) continue; /* * Put the new signal into p_siglist. If the * signal is being masked, look for other signals. */ mask = sigmask(signum); p->p_siglist |= mask; if (p->p_sigmask & mask) continue; } /* * Decide whether the signal should be returned. * Return the signal's number, or fall through * to clear it from the pending mask. */ switch ((int)(intptr_t)p->p_sigacts->ps_sigact[signum]) { case (int)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 %lu) got signal %d\n", (u_long)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; stop(p); if ((p->p_pptr->p_procsig->ps_flag & P_NOCLDSTOP) == 0) psignal(p->p_pptr, SIGCHLD); 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 return (signum); /*NOTREACHED*/ case (int)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. */ return (signum); } p->p_siglist &= ~mask; /* take the signal! */ } /* NOTREACHED */ } /* * 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; int code, mask, returnmask; KASSERT(signum != 0, ("postsig")); mask = sigmask(signum); p->p_siglist &= ~mask; action = ps->ps_sigact[signum]; #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) ktrpsig(p->p_tracep, signum, action, p->p_oldsigmask ? p->p_oldsigmask : p->p_sigmask, 0); #endif STOPEVENT(p, S_SIG, signum); 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. */ KASSERT(action != SIG_IGN && (p->p_sigmask & mask) == 0, ("postsig action")); /* * 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. */ (void) splhigh(); if (p->p_oldsigmask) { returnmask = p->p_oldsigmask; p->p_oldsigmask = 0; } else returnmask = p->p_sigmask; p->p_sigmask |= ps->ps_catchmask[signum] | (mask & ~ps->ps_signodefer); if ((ps->ps_sigreset & mask) != 0) { /* * See setsigvec() for origin of this code. */ p->p_sigcatch &= ~mask; if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) p->p_sigignore |= mask; ps->ps_sigact[signum] = SIG_DFL; } (void) spl0(); p->p_stats->p_ru.ru_nsignals++; if (p->p_sig != signum) { code = 0; } else { code = p->p_code; p->p_code = 0; p->p_sig = 0; } (*p->p_sysent->sv_sendsig)(action, signum, returnmask, code); } } /* * Kill the current process for stated reason. */ void killproc(p, why) struct proc *p; char *why; { log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm, p->p_cred && p->p_ucred ? p->p_ucred->cr_uid : -1, 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_sig = signum; /* * Log signals which would cause core dumps * (Log as LOG_INFO to appease those who don't want * these messages.) * XXX : Todo, as well as euid, write out ruid too */ if (p->p_sysent->sv_coredump != NULL && (*p->p_sysent->sv_coredump)(p) == 0) signum |= WCOREFLAG; if (kern_logsigexit) log(LOG_INFO, "pid %d (%s), uid %d: exited on signal %d%s\n", p->p_pid, p->p_comm, p->p_cred && p->p_ucred ? p->p_ucred->cr_uid : -1, signum &~ WCOREFLAG, signum & WCOREFLAG ? " (core dumped)" : ""); } exit1(p, W_EXITCODE(0, signum)); /* NOTREACHED */ } static char corefilename[MAXPATHLEN+1] = {"%N.core"}; SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, sizeof(corefilename), "process corefile name format string"); /* * expand_name(name, uid, pid) * Expand the name described in corefilename, using name, uid, and pid. * corefilename is a printf-like string, with three format specifiers: * %N name of process ("name") * %P process id (pid) * %U user id (uid) * For example, "%N.core" is the default; they can be disabled completely * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". * This is controlled by the sysctl variable kern.corefile (see above). */ char * expand_name(name, uid, pid) const char *name; uid_t uid; pid_t pid; { char *temp; char buf[11]; /* Buffer for pid/uid -- max 4B */ int i, n; char *format = corefilename; size_t namelen; temp = malloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); if (temp == NULL) return NULL; namelen = strlen(name); for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { int l; switch (format[i]) { case '%': /* Format character */ i++; switch (format[i]) { case '%': temp[n++] = '%'; break; case 'N': /* process name */ if ((n + namelen) > MAXPATHLEN) { log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", pid, name, uid, temp, name); free(temp, M_TEMP); return NULL; } memcpy(temp+n, name, namelen); n += namelen; break; case 'P': /* process id */ l = sprintf(buf, "%u", pid); if ((n + l) > MAXPATHLEN) { log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", pid, name, uid, temp, name); free(temp, M_TEMP); return NULL; } memcpy(temp+n, buf, l); n += l; break; case 'U': /* user id */ l = sprintf(buf, "%u", uid); if ((n + l) > MAXPATHLEN) { log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", pid, name, uid, temp, name); free(temp, M_TEMP); return NULL; } memcpy(temp+n, buf, l); n += l; break; default: log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); } break; default: temp[n++] = format[i]; } } temp[n] = '\0'; return temp; } /* * Nonexistent system call-- signal process (may want to handle it). * Flag error in case process won't see signal immediately (blocked or ignored). */ #ifndef _SYS_SYSPROTO_H_ struct nosys_args { int dummy; }; #endif /* ARGSUSED */ int nosys(p, args) struct proc *p; struct nosys_args *args; { psignal(p, SIGSYS); return (EINVAL); } /* * Send a signal to a SIGIO or SIGURG to a process or process group using * stored credentials rather than those of the current process. */ void pgsigio(sigio, signum, checkctty) struct sigio *sigio; int signum, checkctty; { if (sigio == NULL) return; if (sigio->sio_pgid > 0) { if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, sigio->sio_proc)) psignal(sigio->sio_proc, signum); } else if (sigio->sio_pgid < 0) { struct proc *p; for (p = sigio->sio_pgrp->pg_members.lh_first; p != NULL; p = p->p_pglist.le_next) if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && (checkctty == 0 || (p->p_flag & P_CONTROLT))) psignal(p, signum); } }