/* * 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 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ * $DragonFly: src/sys/kern/kern_sig.c,v 1.37 2005/06/06 15:02:28 dillon Exp $ */ #include "opt_ktrace.h" #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 static int coredump(struct proc *); static char *expand_name(const char *, uid_t, pid_t); static int killpg(int sig, int pgid, int all); static int sig_ffs(sigset_t *set); static int sigprop(int sig); static void stop(struct proc *); #ifdef SMP static void signotify_remote(void *arg); #endif static int kern_sigtimedwait(sigset_t set, siginfo_t *info, struct timespec *timeout); static int filt_sigattach(struct knote *kn); static void filt_sigdetach(struct knote *kn); static int filt_signal(struct knote *kn, long hint); struct filterops sig_filtops = { 0, filt_sigattach, filt_sigdetach, filt_signal }; 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 sig to process q? */ #define CANSIGNAL(q, sig) \ (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ ((sig) == SIGCONT && (q)->p_session == curproc->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_ucred->cr_ruid || \ (uc)->cr_uid == (q)->p_ucred->cr_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"); static int do_coredump = 1; SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, &do_coredump, 0, "Enable/Disable coredumps"); /* * Signal properties and actions. * The array below categorizes the signals and their default actions * according to the following properties: */ #define SA_KILL 0x01 /* terminates process by default */ #define SA_CORE 0x02 /* ditto and coredumps */ #define SA_STOP 0x04 /* suspend process */ #define SA_TTYSTOP 0x08 /* ditto, from tty */ #define SA_IGNORE 0x10 /* ignore by default */ #define SA_CONT 0x20 /* continue if suspended */ #define SA_CANTMASK 0x40 /* non-maskable, catchable */ #define SA_CKPT 0x80 /* checkpoint process */ static int sigproptbl[NSIG] = { SA_KILL, /* SIGHUP */ SA_KILL, /* SIGINT */ SA_KILL|SA_CORE, /* SIGQUIT */ SA_KILL|SA_CORE, /* SIGILL */ SA_KILL|SA_CORE, /* SIGTRAP */ SA_KILL|SA_CORE, /* SIGABRT */ SA_KILL|SA_CORE, /* SIGEMT */ SA_KILL|SA_CORE, /* SIGFPE */ SA_KILL, /* SIGKILL */ SA_KILL|SA_CORE, /* SIGBUS */ SA_KILL|SA_CORE, /* SIGSEGV */ SA_KILL|SA_CORE, /* SIGSYS */ SA_KILL, /* SIGPIPE */ SA_KILL, /* SIGALRM */ SA_KILL, /* SIGTERM */ SA_IGNORE, /* SIGURG */ SA_STOP, /* SIGSTOP */ SA_STOP|SA_TTYSTOP, /* SIGTSTP */ SA_IGNORE|SA_CONT, /* SIGCONT */ SA_IGNORE, /* SIGCHLD */ SA_STOP|SA_TTYSTOP, /* SIGTTIN */ SA_STOP|SA_TTYSTOP, /* SIGTTOU */ SA_IGNORE, /* SIGIO */ SA_KILL, /* SIGXCPU */ SA_KILL, /* SIGXFSZ */ SA_KILL, /* SIGVTALRM */ SA_KILL, /* SIGPROF */ SA_IGNORE, /* SIGWINCH */ SA_IGNORE, /* SIGINFO */ SA_KILL, /* SIGUSR1 */ SA_KILL, /* SIGUSR2 */ SA_IGNORE, /* SIGTHR */ SA_CKPT, /* SIGCKPT */ SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, }; static __inline int sigprop(int sig) { if (sig > 0 && sig < NSIG) return (sigproptbl[_SIG_IDX(sig)]); return (0); } static __inline int sig_ffs(sigset_t *set) { int i; for (i = 0; i < _SIG_WORDS; i++) if (set->__bits[i]) return (ffs(set->__bits[i]) + (i * 32)); return (0); } int kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) { struct thread *td = curthread; struct proc *p = td->td_proc; struct sigacts *ps = p->p_sigacts; if (sig <= 0 || sig > _SIG_MAXSIG) return (EINVAL); if (oact) { oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; oact->sa_flags = 0; if (SIGISMEMBER(ps->ps_sigonstack, sig)) oact->sa_flags |= SA_ONSTACK; if (!SIGISMEMBER(ps->ps_sigintr, sig)) oact->sa_flags |= SA_RESTART; if (SIGISMEMBER(ps->ps_sigreset, sig)) oact->sa_flags |= SA_RESETHAND; if (SIGISMEMBER(ps->ps_signodefer, sig)) oact->sa_flags |= SA_NODEFER; if (SIGISMEMBER(ps->ps_siginfo, sig)) oact->sa_flags |= SA_SIGINFO; if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP) oact->sa_flags |= SA_NOCLDSTOP; if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT) oact->sa_flags |= SA_NOCLDWAIT; } if (act) { if ((sig == SIGKILL || sig == SIGSTOP) && act->sa_handler != SIG_DFL) return (EINVAL); /* * Change setting atomically. */ crit_enter(); ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); if (act->sa_flags & SA_SIGINFO) { ps->ps_sigact[_SIG_IDX(sig)] = (__sighandler_t *)act->sa_sigaction; SIGADDSET(ps->ps_siginfo, sig); } else { ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; SIGDELSET(ps->ps_siginfo, sig); } if (!(act->sa_flags & SA_RESTART)) SIGADDSET(ps->ps_sigintr, sig); else SIGDELSET(ps->ps_sigintr, sig); if (act->sa_flags & SA_ONSTACK) SIGADDSET(ps->ps_sigonstack, sig); else SIGDELSET(ps->ps_sigonstack, sig); if (act->sa_flags & SA_RESETHAND) SIGADDSET(ps->ps_sigreset, sig); else SIGDELSET(ps->ps_sigreset, sig); if (act->sa_flags & SA_NODEFER) SIGADDSET(ps->ps_signodefer, sig); else SIGDELSET(ps->ps_signodefer, sig); if (sig == SIGCHLD) { if (act->sa_flags & SA_NOCLDSTOP) p->p_procsig->ps_flag |= PS_NOCLDSTOP; else p->p_procsig->ps_flag &= ~PS_NOCLDSTOP; if (act->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 &= ~PS_NOCLDWAIT; else p->p_procsig->ps_flag |= PS_NOCLDWAIT; } else { p->p_procsig->ps_flag &= ~PS_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[_SIG_IDX(sig)] == SIG_IGN || (sigprop(sig) & SA_IGNORE && ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { /* never to be seen again */ SIGDELSET(p->p_siglist, sig); if (sig != SIGCONT) /* easier in psignal */ SIGADDSET(p->p_sigignore, sig); SIGDELSET(p->p_sigcatch, sig); } else { SIGDELSET(p->p_sigignore, sig); if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) SIGDELSET(p->p_sigcatch, sig); else SIGADDSET(p->p_sigcatch, sig); } crit_exit(); } return (0); } int sigaction(struct sigaction_args *uap) { struct sigaction act, oact; struct sigaction *actp, *oactp; int error; actp = (uap->act != NULL) ? &act : NULL; oactp = (uap->oact != NULL) ? &oact : NULL; if (actp) { error = copyin(uap->act, actp, sizeof(act)); if (error) return (error); } error = kern_sigaction(uap->sig, actp, oactp); if (oactp && !error) { error = copyout(oactp, uap->oact, sizeof(oact)); } return (error); } /* * Initialize signal state for process 0; * set to ignore signals that are ignored by default. */ void siginit(struct proc *p) { int i; for (i = 1; i <= NSIG; i++) if (sigprop(i) & SA_IGNORE && i != SIGCONT) SIGADDSET(p->p_sigignore, i); } /* * Reset signals for an exec of the specified process. */ void execsigs(struct proc *p) { struct sigacts *ps = p->p_sigacts; int sig; /* * Reset caught signals. Held signals remain held * through p_sigmask (unless they were caught, * and are now ignored by default). */ while (SIGNOTEMPTY(p->p_sigcatch)) { sig = sig_ffs(&p->p_sigcatch); SIGDELSET(p->p_sigcatch, sig); if (sigprop(sig) & SA_IGNORE) { if (sig != SIGCONT) SIGADDSET(p->p_sigignore, sig); SIGDELSET(p->p_siglist, sig); } ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; } /* * Reset stack state to the user stack. * Clear set of signals caught on the signal stack. */ p->p_sigstk.ss_flags = SS_DISABLE; p->p_sigstk.ss_size = 0; p->p_sigstk.ss_sp = 0; p->p_flag &= ~P_ALTSTACK; /* * Reset no zombies if child dies flag as Solaris does. */ p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; } /* * kern_sigprocmask() - MP SAFE ONLY IF p == curproc * * Manipulate signal mask. This routine is MP SAFE *ONLY* if * p == curproc. */ int kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) { struct thread *td = curthread; struct proc *p = td->td_proc; int error; if (oset != NULL) *oset = p->p_sigmask; error = 0; if (set != NULL) { switch (how) { case SIG_BLOCK: SIG_CANTMASK(*set); SIGSETOR(p->p_sigmask, *set); break; case SIG_UNBLOCK: SIGSETNAND(p->p_sigmask, *set); break; case SIG_SETMASK: SIG_CANTMASK(*set); p->p_sigmask = *set; break; default: error = EINVAL; break; } } return (error); } /* * sigprocmask() - MP SAFE */ int sigprocmask(struct sigprocmask_args *uap) { sigset_t set, oset; sigset_t *setp, *osetp; int error; setp = (uap->set != NULL) ? &set : NULL; osetp = (uap->oset != NULL) ? &oset : NULL; if (setp) { error = copyin(uap->set, setp, sizeof(set)); if (error) return (error); } error = kern_sigprocmask(uap->how, setp, osetp); if (osetp && !error) { error = copyout(osetp, uap->oset, sizeof(oset)); } return (error); } int kern_sigpending(struct __sigset *set) { struct thread *td = curthread; struct proc *p = td->td_proc; *set = p->p_siglist; return (0); } int sigpending(struct sigpending_args *uap) { sigset_t set; int error; error = kern_sigpending(&set); if (error == 0) error = copyout(&set, uap->set, sizeof(set)); return (error); } /* * Suspend process until signal, providing mask to be set * in the meantime. */ int kern_sigsuspend(struct __sigset *set) { struct thread *td = curthread; struct proc *p = td->td_proc; struct sigacts *ps = p->p_sigacts; /* * When returning from sigsuspend, 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_flag |= P_OLDMASK; SIG_CANTMASK(*set); p->p_sigmask = *set; while (tsleep(ps, PCATCH, "pause", 0) == 0) /* void */; /* always return EINTR rather than ERESTART... */ return (EINTR); } /* * Note nonstandard calling convention: libc stub passes mask, not * pointer, to save a copyin. */ int sigsuspend(struct sigsuspend_args *uap) { sigset_t mask; int error; error = copyin(uap->sigmask, &mask, sizeof(mask)); if (error) return (error); error = kern_sigsuspend(&mask); return (error); } int kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) { struct thread *td = curthread; struct proc *p = td->td_proc; if ((p->p_flag & P_ALTSTACK) == 0) p->p_sigstk.ss_flags |= SS_DISABLE; if (oss) *oss = p->p_sigstk; if (ss) { if (ss->ss_flags & SS_DISABLE) { if (p->p_sigstk.ss_flags & SS_ONSTACK) return (EINVAL); p->p_flag &= ~P_ALTSTACK; p->p_sigstk.ss_flags = ss->ss_flags; } else { if (ss->ss_size < p->p_sysent->sv_minsigstksz) return (ENOMEM); p->p_flag |= P_ALTSTACK; p->p_sigstk = *ss; } } return (0); } int sigaltstack(struct sigaltstack_args *uap) { stack_t ss, oss; int error; if (uap->ss) { error = copyin(uap->ss, &ss, sizeof(ss)); if (error) return (error); } error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL); if (error == 0 && uap->oss) error = copyout(&oss, uap->oss, sizeof(*uap->oss)); return (error); } /* * Common code for kill process group/broadcast kill. * cp is calling process. */ static int killpg(int sig, int pgid, int all) { struct proc *cp = curproc; struct proc *p; struct pgrp *pgrp; int nfound = 0; if (all) { /* * broadcast */ FOREACH_PROC_IN_SYSTEM(p) { if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || p == cp || !CANSIGNAL(p, sig)) continue; nfound++; if (sig) psignal(p, sig); } } 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 || p->p_stat == SZOMB || !CANSIGNAL(p, sig)) continue; nfound++; if (sig) psignal(p, sig); } } return (nfound ? 0 : ESRCH); } int kern_kill(int sig, int pid) { struct thread *td = curthread; struct proc *p = td->td_proc; if ((u_int)sig > _SIG_MAXSIG) return (EINVAL); if (pid > 0) { /* kill single process */ if ((p = pfind(pid)) == NULL) return (ESRCH); if (!CANSIGNAL(p, sig)) return (EPERM); if (sig) psignal(p, sig); return (0); } switch (pid) { case -1: /* broadcast signal */ return (killpg(sig, 0, 1)); case 0: /* signal own process group */ return (killpg(sig, 0, 0)); default: /* negative explicit process group */ return (killpg(sig, -pid, 0)); } /* NOTREACHED */ } int kill(struct kill_args *uap) { int error; error = kern_kill(uap->signum, uap->pid); return (error); } /* * Send a signal to a process group. */ void gsignal(int pgid, int sig) { struct pgrp *pgrp; if (pgid && (pgrp = pgfind(pgid))) pgsignal(pgrp, sig, 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 sig, 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, sig); } /* * 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 sig, u_long code) { struct sigacts *ps = p->p_sigacts; if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && !SIGISMEMBER(p->p_sigmask, sig)) { p->p_stats->p_ru.ru_nsignals++; #ifdef KTRACE if (KTRPOINT(p->p_thread, KTR_PSIG)) ktrpsig(p->p_tracep, sig, ps->ps_sigact[_SIG_IDX(sig)], &p->p_sigmask, code); #endif (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, &p->p_sigmask, code); SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); if (!SIGISMEMBER(ps->ps_signodefer, sig)) SIGADDSET(p->p_sigmask, sig); if (SIGISMEMBER(ps->ps_sigreset, sig)) { /* * See kern_sigaction() for origin of this code. */ SIGDELSET(p->p_sigcatch, sig); if (sig != SIGCONT && sigprop(sig) & SA_IGNORE) SIGADDSET(p->p_sigignore, sig); ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; } } else { p->p_code = code; /* XXX for core dump/debugger */ p->p_sig = sig; /* XXX to verify code */ psignal(p, sig); } } /* * 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. */ /* * temporary hack to allow checkpoint code to continue to * be in a module for the moment */ void psignal(struct proc *p, int sig) { int prop; sig_t action; if (sig > _SIG_MAXSIG || sig <= 0) { printf("psignal: signal %d\n", sig); panic("psignal signal number"); } crit_enter(); KNOTE(&p->p_klist, NOTE_SIGNAL | sig); crit_exit(); prop = sigprop(sig); /* * 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 (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT)) return; if (SIGISMEMBER(p->p_sigmask, sig)) action = SIG_HOLD; else if (SIGISMEMBER(p->p_sigcatch, sig)) 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) SIG_STOPSIGMASK(p->p_siglist); 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; } SIG_CONTSIGMASK(p->p_siglist); } SIGADDSET(p->p_siglist, sig); /* * Defer further processing for signals which are held, * except that stopped processes must be continued by SIGCONT. */ if (action == SIG_HOLD && (!(prop & SA_CONT) || p->p_stat != SSTOP)) return; crit_enter(); 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, sig); 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 run; /* * If a child holding parent blocked, * stopping could cause deadlock. */ if (p->p_flag & P_PPWAIT) goto out; SIGDELSET(p->p_siglist, sig); p->p_xstat = sig; if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) psignal(p->p_pptr, SIGCHLD); stop(p); goto out; } else { goto run; } /*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 (sig == SIGKILL) goto run; 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, sig); if (action == SIG_CATCH) goto run; if (p->p_wchan == 0) goto run; clrrunnable(p, 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, sig); 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->p_thread); 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. * * Note that p_thread may be NULL or may not be completely * initialized if the process is in the SIDL or SZOMB state. * * For SMP we may have to forward the request to another cpu. * YYY the MP lock prevents the target process from moving * to another cpu, see kern/kern_switch.c * * If the target thread is waiting on its message port, * wakeup the target thread so it can check (or ignore) * the new signal. YYY needs cleanup. */ #ifdef SMP if (p == lwkt_preempted_proc()) { signotify(); } else if (p->p_stat == SRUN) { struct thread *td = p->p_thread; KASSERT(td != NULL, ("pid %d NULL p_thread stat %d flags %08x", p->p_pid, p->p_stat, p->p_flag)); if (td->td_gd != mycpu) lwkt_send_ipiq(td->td_gd, signotify_remote, p); else if (td->td_msgport.mp_flags & MSGPORTF_WAITING) lwkt_schedule(td); } #else if (p == lwkt_preempted_proc()) { signotify(); } else if (p->p_stat == SRUN) { struct thread *td = p->p_thread; KASSERT(td != NULL, ("pid %d NULL p_thread stat %d flags %08x", p->p_pid, p->p_stat, p->p_flag)); if (td->td_msgport.mp_flags & MSGPORTF_WAITING) lwkt_schedule(td); } #endif goto out; } /*NOTREACHED*/ run: setrunnable(p); out: crit_exit(); } #ifdef SMP /* * This function is called via an IPI. We will be in a critical section but * the MP lock will NOT be held. Also note that by the time the ipi message * gets to us the process 'p' (arg) may no longer be scheduled or even valid. */ static void signotify_remote(void *arg) { struct proc *p = arg; if (p == lwkt_preempted_proc()) { signotify(); } else { struct thread *td = p->p_thread; if (td->td_msgport.mp_flags & MSGPORTF_WAITING) lwkt_schedule(td); } } #endif static int kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) { sigset_t savedmask, set; struct proc *p = curproc; int error, sig, hz, timevalid = 0; struct timespec rts, ets, ts; struct timeval tv; error = 0; sig = 0; SIG_CANTMASK(waitset); savedmask = p->p_sigmask; if (timeout) { if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) { timevalid = 1; getnanouptime(&rts); ets = rts; timespecadd(&ets, timeout); } } for (;;) { set = p->p_siglist; SIGSETAND(set, waitset); if ((sig = sig_ffs(&set)) != 0) { SIGFILLSET(p->p_sigmask); SIGDELSET(p->p_sigmask, sig); SIG_CANTMASK(p->p_sigmask); sig = issignal(p); /* * It may be a STOP signal, in the case, issignal * returns 0, because we may stop there, and new * signal can come in, we should restart if we got * nothing. */ if (sig == 0) continue; else break; } /* * Previous checking got nothing, and we retried but still * got nothing, we should return the error status. */ if (error) break; /* * POSIX says this must be checked after looking for pending * signals. */ if (timeout) { if (!timevalid) { error = EINVAL; break; } getnanouptime(&rts); if (timespeccmp(&rts, &ets, >=)) { error = EAGAIN; break; } ts = ets; timespecsub(&ts, &rts); TIMESPEC_TO_TIMEVAL(&tv, &ts); hz = tvtohz_high(&tv); } else hz = 0; p->p_sigmask = savedmask; SIGSETNAND(p->p_sigmask, waitset); error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); if (timeout) { if (error == ERESTART) { /* can not restart a timeout wait. */ error = EINTR; } else if (error == EAGAIN) { /* will calculate timeout by ourself. */ error = 0; } } /* Retry ... */ } p->p_sigmask = savedmask; if (sig) { error = 0; bzero(info, sizeof(*info)); info->si_signo = sig; SIGDELSET(p->p_siglist, sig); /* take the signal! */ } return (error); } int sigtimedwait(struct sigtimedwait_args *uap) { struct timespec ts; struct timespec *timeout; sigset_t set; siginfo_t info; int error; if (uap->timeout) { error = copyin(uap->timeout, &ts, sizeof(ts)); if (error) return (error); timeout = &ts; } else { timeout = NULL; } error = copyin(uap->set, &set, sizeof(set)); if (error) return (error); error = kern_sigtimedwait(set, &info, timeout); if (error) return (error); if (uap->info) error = copyout(&info, uap->info, sizeof(info)); /* Repost if we got an error. */ if (error) psignal(curproc, info.si_signo); else uap->sysmsg_result = info.si_signo; return (error); } int sigwaitinfo(struct sigwaitinfo_args *uap) { siginfo_t info; sigset_t set; int error; error = copyin(uap->set, &set, sizeof(set)); if (error) return (error); error = kern_sigtimedwait(set, &info, NULL); if (error) return (error); if (uap->info) error = copyout(&info, uap->info, sizeof(info)); /* Repost if we got an error. */ if (error) psignal(curproc, info.si_signo); else uap->sysmsg_result = info.si_signo; return (error); } /* * If the current process has received a signal that would interrupt a * system call, return EINTR or ERESTART as appropriate. */ int iscaught(struct proc *p) { int sig; if (p) { if ((sig = CURSIG(p)) != 0) { if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) return (EINTR); return (ERESTART); } } return(EWOULDBLOCK); } /* * 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 (sig = CURSIG(curproc)) * postsig(sig); */ int issignal(struct proc *p) { sigset_t mask; int sig, prop; for (;;) { int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); mask = p->p_siglist; SIGSETNAND(mask, p->p_sigmask); if (p->p_flag & P_PPWAIT) SIG_STOPSIGMASK(mask); if (!SIGNOTEMPTY(mask)) /* no signal to send */ return (0); sig = sig_ffs(&mask); STOPEVENT(p, S_SIG, sig); /* * We should see pending but ignored signals * only if P_TRACED was on when they were posted. */ if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { SIGDELSET(p->p_siglist, sig); 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 = sig; psignal(p->p_pptr, SIGCHLD); do { stop(p); mi_switch(p); } while (!trace_req(p) && p->p_flag & P_TRACED); /* * If parent wants us to take the signal, * then it will leave it in p->p_xstat; * otherwise we just look for signals again. */ SIGDELSET(p->p_siglist, sig); /* clear old signal */ sig = p->p_xstat; if (sig == 0) continue; /* * Put the new signal into p_siglist. If the * signal is being masked, look for other signals. */ SIGADDSET(p->p_siglist, sig); if (SIGISMEMBER(p->p_sigmask, sig)) continue; /* * 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; } prop = sigprop(sig); /* * 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[_SIG_IDX(sig)]) { 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, sig); #endif break; /* == ignore */ } /* * Handle the in-kernel checkpoint action */ if (prop & SA_CKPT) { checkpoint_signal_handler(p); break; } /* * 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 = sig; stop(p); if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) psignal(p->p_pptr, SIGCHLD); mi_switch(p); break; } else if (prop & SA_IGNORE) { /* * Except for SIGCONT, shouldn't get here. * Default action is to ignore; drop it. */ break; /* == ignore */ } else { return (sig); } /*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 (sig); } SIGDELSET(p->p_siglist, sig); /* 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(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(int sig) { struct proc *p = curproc; struct sigacts *ps = p->p_sigacts; sig_t action; sigset_t returnmask; int code; KASSERT(sig != 0, ("postsig")); SIGDELSET(p->p_siglist, sig); action = ps->ps_sigact[_SIG_IDX(sig)]; #ifdef KTRACE if (KTRPOINT(p->p_thread, KTR_PSIG)) ktrpsig(p->p_tracep, sig, action, p->p_flag & P_OLDMASK ? &p->p_oldsigmask : &p->p_sigmask, 0); #endif STOPEVENT(p, S_SIG, sig); if (action == SIG_DFL) { /* * Default action, where the default is to kill * the process. (Other cases were ignored above.) */ sigexit(p, sig); /* NOTREACHED */ } else { /* * If we get here, the signal must be caught. */ KASSERT(action != SIG_IGN && !SIGISMEMBER(p->p_sigmask, sig), ("postsig action")); /* * Set the new mask value and also defer further * occurrences of this signal. * * Special case: user has done a sigsuspend. Here the * current mask is not of interest, but rather the * mask from before the sigsuspend is what we want * restored after the signal processing is completed. */ crit_enter(); if (p->p_flag & P_OLDMASK) { returnmask = p->p_oldsigmask; p->p_flag &= ~P_OLDMASK; } else { returnmask = p->p_sigmask; } SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); if (!SIGISMEMBER(ps->ps_signodefer, sig)) SIGADDSET(p->p_sigmask, sig); if (SIGISMEMBER(ps->ps_sigreset, sig)) { /* * See kern_sigaction() for origin of this code. */ SIGDELSET(p->p_sigcatch, sig); if (sig != SIGCONT && sigprop(sig) & SA_IGNORE) SIGADDSET(p->p_sigignore, sig); ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; } crit_exit(); p->p_stats->p_ru.ru_nsignals++; if (p->p_sig != sig) { code = 0; } else { code = p->p_code; p->p_code = 0; p->p_sig = 0; } (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); } } /* * Kill the current process for stated reason. */ void killproc(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_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(struct proc *p, int sig) { p->p_acflag |= AXSIG; if (sigprop(sig) & SA_CORE) { p->p_sig = sig; /* * 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 (coredump(p) == 0) sig |= 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_ucred ? p->p_ucred->cr_uid : -1, sig &~ WCOREFLAG, sig & WCOREFLAG ? " (core dumped)" : ""); } exit1(W_EXITCODE(0, sig)); /* 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). */ static char * expand_name(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; } /* * Dump a process' core. The main routine does some * policy checking, and creates the name of the coredump; * then it passes on a vnode and a size limit to the process-specific * coredump routine if there is one; if there _is not_ one, it returns * ENOSYS; otherwise it returns the error from the process-specific routine. */ static int coredump(struct proc *p) { struct vnode *vp; struct ucred *cred = p->p_ucred; struct thread *td = p->p_thread; struct flock lf; struct nlookupdata nd; struct vattr vattr; int error, error1; char *name; /* name of corefile */ off_t limit; STOPEVENT(p, S_CORE, 0); if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) return (EFAULT); /* * Note that the bulk of limit checking is done after * the corefile is created. The exception is if the limit * for corefiles is 0, in which case we don't bother * creating the corefile at all. This layout means that * a corefile is truncated instead of not being created, * if it is larger than the limit. */ limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; if (limit == 0) return EFBIG; name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); if (name == NULL) return (EINVAL); error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); if (error == 0) error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); free(name, M_TEMP); if (error) { nlookup_done(&nd); return (error); } vp = nd.nl_open_vp; nd.nl_open_vp = NULL; nlookup_done(&nd); VOP_UNLOCK(vp, 0, td); lf.l_whence = SEEK_SET; lf.l_start = 0; lf.l_len = 0; lf.l_type = F_WRLCK; error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK); if (error) goto out2; /* Don't dump to non-regular files or files with links. */ if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, td) || vattr.va_nlink != 1) { error = EFAULT; goto out1; } VATTR_NULL(&vattr); vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); vattr.va_size = 0; VOP_LEASE(vp, td, cred, LEASE_WRITE); VOP_SETATTR(vp, &vattr, cred, td); p->p_acflag |= ACORE; VOP_UNLOCK(vp, 0, td); error = p->p_sysent->sv_coredump ? p->p_sysent->sv_coredump(p, vp, limit) : ENOSYS; out1: lf.l_type = F_UNLCK; VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK); out2: error1 = vn_close(vp, FWRITE, td); 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 nosys(struct nosys_args *args) { psignal(curproc, SIGSYS); return (EINVAL); } /* * Send a SIGIO or SIGURG signal to a process or process group using * stored credentials rather than those of the current process. */ void pgsigio(struct sigio *sigio, int sig, int 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, sig); } else if (sigio->sio_pgid < 0) { struct proc *p; LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && (checkctty == 0 || (p->p_flag & P_CONTROLT))) psignal(p, 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 */ /* XXX lock the proc here while adding to the list? */ 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); }