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freebsd/sys/kern/kern_sig.c
Sean Eric Fagan f3a6cf7052 Make prototype match function.
1999-09-01 16:21:57 +00:00

1467 lines
36 KiB
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/*
* 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
* $FreeBSD$
*/
#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 char *expand_name __P((const char *, uid_t, pid_t));
static int coredump __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 (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).
*/
static 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;
}
/*
* 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(p)
register struct proc *p;
{
register struct vnode *vp;
register struct ucred *cred = p->p_cred->pc_ucred;
struct nameidata 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)
return (EFAULT);
/*
* Note that this layout means that limit checking is done
* AFTER the corefile name is created. This could happen
* other ways as well, so I'm not too worried about it, but
* it is potentially confusing.
*/
name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p);
error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
free(name, M_TEMP);
if (error)
return (error);
vp = nd.ni_vp;
/* Don't dump to non-regular files or files with links. */
if (vp->v_type != VREG ||
VOP_GETATTR(vp, &vattr, cred, p) || vattr.va_nlink != 1) {
error = EFAULT;
goto out;
}
VATTR_NULL(&vattr);
vattr.va_size = 0;
VOP_LEASE(vp, p, cred, LEASE_WRITE);
VOP_SETATTR(vp, &vattr, cred, p);
p->p_acflag |= ACORE;
limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
error = p->p_sysent->sv_coredump ?
p->p_sysent->sv_coredump(p, vp, limit) :
ENOSYS;
out:
VOP_UNLOCK(vp, 0, p);
error1 = vn_close(vp, FWRITE, cred, p);
if (error == 0)
error = error1;
return (error);
}
/*
* Nonexistent system call-- signal process (may want to handle it).
* Flag error in case process won't see signal immediately (blocked or ignored).
*/
#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);
}
}
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