diff options
Diffstat (limited to 'sys/kern/kern_sig.c')
| -rw-r--r-- | sys/kern/kern_sig.c | 1455 |
1 files changed, 1455 insertions, 0 deletions
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c new file mode 100644 index 0000000..bf89d8a --- /dev/null +++ b/sys/kern/kern_sig.c @@ -0,0 +1,1455 @@ +/* + * 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 1.52 1999/01/08 17:31:10 eivind Exp $ + */ + +#include "opt_compat.h" +#include "opt_ktrace.h" + +#define SIGPROP /* include signal properties table */ +#include <sys/param.h> +#include <sys/kernel.h> +#include <sys/sysproto.h> +#include <sys/signalvar.h> +#include <sys/resourcevar.h> +#include <sys/namei.h> +#include <sys/vnode.h> +#include <sys/proc.h> +#include <sys/pioctl.h> +#include <sys/systm.h> +#include <sys/acct.h> +#include <sys/fcntl.h> +#include <sys/wait.h> +#include <sys/ktrace.h> +#include <sys/syslog.h> +#include <sys/stat.h> +#include <sys/sysent.h> +#include <sys/sysctl.h> +#include <sys/malloc.h> + +#include <machine/cpu.h> +#ifdef SMP +#include <machine/smp.h> +#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, ""); + +/* + * 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)) + +/* + * 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, ""); + +#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) { + sa->sa_handler = ps->ps_sigact[signum]; + sa->sa_mask = ps->ps_catchmask[signum]; + bit = sigmask(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; +#ifndef COMPAT_LINUX_THREADS + if (signum == SIGCHLD && p->p_flag & P_NOCLDSTOP) +#else + if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDSTOP) +#endif /* COMPAT_LINUX_THREADS */ + sa->sa_flags |= SA_NOCLDSTOP; +#ifndef COMPAT_LINUX_THREADS + if (signum == SIGCHLD && p->p_flag & P_NOCLDWAIT) +#else + if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDWAIT) +#endif /* COMPAT_LINUX_THREADS */ + 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_sigact[signum] = sa->sa_handler; + ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; + 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) +#ifndef COMPAT_LINUX_THREADS + p->p_flag |= P_NOCLDSTOP; + else + p->p_flag &= ~P_NOCLDSTOP; +#else + p->p_procsig->ps_flag |= P_NOCLDSTOP; + else + p->p_procsig->ps_flag &= ~P_NOCLDSTOP; +#endif /* COMPAT_LINUX_THREADS */ + 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) +#ifndef COMPAT_LINUX_THREADS + p->p_flag &= ~P_NOCLDWAIT; + else + p->p_flag |= P_NOCLDWAIT; +#else + p->p_procsig->ps_flag &= ~P_NOCLDWAIT; + else + p->p_procsig->ps_flag |= P_NOCLDWAIT; +#endif /* COMPAT_LINUX_THREADS */ + } else +#ifndef COMPAT_LINUX_THREADS + p->p_flag &= ~P_NOCLDWAIT; +#else + p->p_procsig->ps_flag &= ~P_NOCLDWAIT; +#endif /* COMPAT_LINUX_THREADS */ + } + /* + * 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 (sa->sa_handler == SIG_IGN || + (sigprop[signum] & SA_IGNORE && sa->sa_handler == 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 (sa->sa_handler == 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; +} + +/* + * 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; +#ifndef COMPAT_SUNOS +#ifndef COMPAT_LINUX_THREADS + if (signum == SIGCHLD && p->p_flag & P_NOCLDSTOP) +#else + if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDSTOP) +#endif /* COMPAT_LINUX_THREADS */ + 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. + */ +#ifndef COMPAT_LINUX_THREADS + ps->ps_oldmask = p->p_sigmask; + ps->ps_flags |= SAS_OLDMASK; +#else + p->p_oldsigmask = p->p_sigmask; +#endif /* COMPAT_LINUX_THREADS */ + 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 { +#ifndef COMPAT_LINUX_THREADS + ps->ps_code = code; /* XXX for core dump/debugger */ + ps->ps_sig = signum; /* XXX to verify code */ +#else + p->p_code = code; /* XXX for core dump/debugger */ + p->p_sig = signum; /* XXX to verify code */ +#endif /* COMPAT_LINUX_THREADS */ + 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.) + */ +#ifndef COMPAT_LINUX_THREADS + if (p->p_sigignore & mask) +#else + if ((p->p_sigignore & mask) || (p->p_flag & P_WEXIT)) +#endif /* COMPAT_LINUX_THREADS */ + 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; +#ifndef COMPAT_LINUX_THREADS + if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) +#else + if ((p->p_pptr->p_procsig->ps_flag & P_NOCLDSTOP) == 0) +#endif /* COMPAT_LINUX_THREADS */ + 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); +#ifndef COMPAT_LINUX_THREADS + if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) +#else + if ((p->p_pptr->p_procsig->ps_flag & P_NOCLDSTOP) == 0) +#endif /* COMPAT_LINUX_THREADS */ + 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, +#ifndef COMPAT_LINUX_THREADS + signum, action, ps->ps_flags & SAS_OLDMASK ? + ps->ps_oldmask : p->p_sigmask, 0); +#else + signum, action, p->p_oldsigmask ? + p->p_oldsigmask : p->p_sigmask, 0); +#endif /* COMPAT_LINUX_THREADS */ +#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(); +#ifndef COMPAT_LINUX_THREADS + if (ps->ps_flags & SAS_OLDMASK) { + returnmask = ps->ps_oldmask; + ps->ps_flags &= ~SAS_OLDMASK; +#else + if (p->p_oldsigmask) { + returnmask = p->p_oldsigmask; + p->p_oldsigmask = 0; +#endif /* COMPAT_LINUX_THREADS */ + } 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++; +#ifndef COMPAT_LINUX_THREADS + if (ps->ps_sig != signum) { +#else + if (p->p_sig != signum) { +#endif /* COMPAT_LINUX_THREADS */ + code = 0; + } else { +#ifndef COMPAT_LINUX_THREADS + code = ps->ps_code; + ps->ps_code = 0; + ps->ps_sig = 0; +#else + code = p->p_code; + p->p_code = 0; + p->p_sig = 0; +#endif /* COMPAT_LINUX_THREADS */ + } + (*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) { +#ifndef COMPAT_LINUX_THREADS + p->p_sigacts->ps_sig = signum; +#else + p->p_sig = signum; +#endif /* COMPAT_LINUX_THREADS */ + /* + * 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; int uid; int pid; { + char *temp; + char buf[11]; /* Buffer for pid/uid -- max 4B */ + int i, n; + char *format = corefilename; + + temp = malloc(MAXPATHLEN + 3, M_TEMP, M_NOWAIT); + if (temp == NULL) + return NULL; + bzero(temp, MAXPATHLEN+3); + for (i = 0, n = 0; i < MAXPATHLEN && format[i]; i++) { + int l; + switch (format[i]) { + case '%': /* Format character */ + i++; + switch (format[i]) { + case '%': + temp[n++] = '%'; + break; + case 'N': /* process name */ + l = strlen(name); + if ((n + l) > MAXPATHLEN) { + log(LOG_ERR, "pid %d (%s), uid (%d): Path `%s%s' is too long\n", + pid, name, uid, temp, name); + free(temp, M_TEMP); + return NULL; + } + memcpy(temp+n, name, l); + n += l; + break; + case 'P': /* process id */ + sprintf(buf, "%u", pid); + l = strlen(buf); + if ((n + l) > MAXPATHLEN) { + log(LOG_ERR, "pid %d (%s), uid (%d): 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 */ + sprintf(buf, "%u", uid); + l = strlen(buf); + if ((n + l) > MAXPATHLEN) { + log(LOG_ERR, "pid %d (%s), uid (%d): 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]; + } + } + 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); + } +} |
