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NetBSD/sys/kern/kern_sig.c
thorpej 33d6023447 Unshare signal actions on exec. 
From Matthew Orgass <darkstar@pgh.net>.
2001-07-18 05:34:58 +00:00

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/* $NetBSD: kern_sig.c,v 1.115 2001/07/18 05:34:58 thorpej Exp $ */
/*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_sig.c 8.14 (Berkeley) 5/14/95
*/
#include "opt_ktrace.h"
#include "opt_compat_sunos.h"
#include "opt_compat_netbsd32.h"
#define SIGPROP /* include signal properties table */
#include <sys/param.h>
#include <sys/signalvar.h>
#include <sys/resourcevar.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/timeb.h>
#include <sys/times.h>
#include <sys/buf.h>
#include <sys/acct.h>
#include <sys/file.h>
#include <sys/kernel.h>
#include <sys/wait.h>
#include <sys/ktrace.h>
#include <sys/syslog.h>
#include <sys/stat.h>
#include <sys/core.h>
#include <sys/filedesc.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <machine/cpu.h>
#include <sys/user.h> /* for coredump */
#include <uvm/uvm_extern.h>
static void proc_stop(struct proc *p);
void killproc(struct proc *, char *);
static int build_corename(struct proc *, char [MAXPATHLEN]);
sigset_t contsigmask, stopsigmask, sigcantmask;
struct pool sigacts_pool; /* memory pool for sigacts structures */
int (*coredump32_hook)(struct proc *p, struct vnode *vp);
/*
* Can process p, with pcred pc, send the signal signum to process q?
*/
#define CANSIGNAL(p, pc, q, signum) \
((pc)->pc_ucred->cr_uid == 0 || \
(pc)->p_ruid == (q)->p_cred->p_ruid || \
(pc)->pc_ucred->cr_uid == (q)->p_cred->p_ruid || \
(pc)->p_ruid == (q)->p_ucred->cr_uid || \
(pc)->pc_ucred->cr_uid == (q)->p_ucred->cr_uid || \
((signum) == SIGCONT && (q)->p_session == (p)->p_session))
/*
* Initialize signal-related data structures.
*/
void
signal_init(void)
{
pool_init(&sigacts_pool, sizeof(struct sigacts), 0, 0, 0, "sigapl",
0, pool_page_alloc_nointr, pool_page_free_nointr, M_SUBPROC);
}
/*
* Create an initial sigctx structure, using the same signal state
* as p. If 'share' is set, share the sigctx_proc part, otherwise just
* copy it from parent.
*/
void
sigactsinit(struct proc *np, struct proc *pp, int share)
{
struct sigacts *ps;
if (share) {
np->p_sigacts = pp->p_sigacts;
pp->p_sigacts->sa_refcnt++;
} else {
ps = pool_get(&sigacts_pool, PR_WAITOK);
if (pp)
memcpy(ps, pp->p_sigacts, sizeof(struct sigacts));
else
memset(ps, '\0', sizeof(struct sigacts));
ps->sa_refcnt = 1;
np->p_sigacts = ps;
}
}
/*
* Make this process not share its sigctx, maintaining all
* signal state.
*/
void
sigactsunshare(struct proc *p)
{
struct sigacts *oldps;
if (p->p_sigacts->sa_refcnt == 1)
return;
oldps = p->p_sigacts;
sigactsinit(p, NULL, 0);
if (--oldps->sa_refcnt == 0)
pool_put(&sigacts_pool, oldps);
}
/*
* Release a sigctx structure.
*/
void
sigactsfree(struct proc *p)
{
struct sigacts *ps;
ps = p->p_sigacts;
if (--ps->sa_refcnt > 0)
return;
pool_put(&sigacts_pool, ps);
}
int
sigaction1(struct proc *p, int signum, const struct sigaction *nsa,
struct sigaction *osa)
{
struct sigacts *ps;
int prop;
ps = p->p_sigacts;
if (signum <= 0 || signum >= NSIG)
return (EINVAL);
if (osa)
*osa = SIGACTION_PS(ps, signum);
if (nsa) {
if (nsa->sa_flags & ~SA_ALLBITS)
return (EINVAL);
prop = sigprop[signum];
if (prop & SA_CANTMASK)
return (EINVAL);
(void) splsched(); /* XXXSMP */
SIGACTION_PS(ps, signum) = *nsa;
sigminusset(&sigcantmask, &SIGACTION_PS(ps, signum).sa_mask);
if ((prop & SA_NORESET) != 0)
SIGACTION_PS(ps, signum).sa_flags &= ~SA_RESETHAND;
if (signum == SIGCHLD) {
if (nsa->sa_flags & SA_NOCLDSTOP)
p->p_flag |= P_NOCLDSTOP;
else
p->p_flag &= ~P_NOCLDSTOP;
if (nsa->sa_flags & SA_NOCLDWAIT) {
/*
* Paranoia: since SA_NOCLDWAIT is implemented
* by reparenting the dying child to PID 1 (and
* trust it to reap the zombie), PID 1 itself
* is forbidden to set SA_NOCLDWAIT.
*/
if (p->p_pid == 1)
p->p_flag &= ~P_NOCLDWAIT;
else
p->p_flag |= P_NOCLDWAIT;
} else
p->p_flag &= ~P_NOCLDWAIT;
}
if ((nsa->sa_flags & SA_NODEFER) == 0)
sigaddset(&SIGACTION_PS(ps, signum).sa_mask, signum);
else
sigdelset(&SIGACTION_PS(ps, signum).sa_mask, signum);
/*
* Set bit in p_sigctx.ps_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_sigctx.ps_sigignore, as we have to restart the process.
*/
if (nsa->sa_handler == SIG_IGN ||
(nsa->sa_handler == SIG_DFL && (prop & SA_IGNORE) != 0)) {
/* never to be seen again */
sigdelset(&p->p_sigctx.ps_siglist, signum);
if (signum != SIGCONT) {
/* easier in psignal */
sigaddset(&p->p_sigctx.ps_sigignore, signum);
}
sigdelset(&p->p_sigctx.ps_sigcatch, signum);
} else {
sigdelset(&p->p_sigctx.ps_sigignore, signum);
if (nsa->sa_handler == SIG_DFL)
sigdelset(&p->p_sigctx.ps_sigcatch, signum);
else
sigaddset(&p->p_sigctx.ps_sigcatch, signum);
}
(void) spl0();
}
return (0);
}
/* ARGSUSED */
int
sys___sigaction14(struct proc *p, void *v, register_t *retval)
{
struct sys___sigaction14_args /* {
syscallarg(int) signum;
syscallarg(const struct sigaction *) nsa;
syscallarg(struct sigaction *) osa;
} */ *uap = v;
struct sigaction nsa, osa;
int error;
if (SCARG(uap, nsa)) {
error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa));
if (error)
return (error);
}
error = sigaction1(p, SCARG(uap, signum),
SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0);
if (error)
return (error);
if (SCARG(uap, osa)) {
error = copyout(&osa, SCARG(uap, osa), sizeof(osa));
if (error)
return (error);
}
return (0);
}
/*
* Initialize signal state for process 0;
* set to ignore signals that are ignored by default and disable the signal
* stack.
*/
void
siginit(struct proc *p)
{
struct sigacts *ps;
int signum, prop;
ps = p->p_sigacts;
sigemptyset(&contsigmask);
sigemptyset(&stopsigmask);
sigemptyset(&sigcantmask);
for (signum = 1; signum < NSIG; signum++) {
prop = sigprop[signum];
if (prop & SA_CONT)
sigaddset(&contsigmask, signum);
if (prop & SA_STOP)
sigaddset(&stopsigmask, signum);
if (prop & SA_CANTMASK)
sigaddset(&sigcantmask, signum);
if (prop & SA_IGNORE && signum != SIGCONT)
sigaddset(&p->p_sigctx.ps_sigignore, signum);
sigemptyset(&SIGACTION_PS(ps, signum).sa_mask);
SIGACTION_PS(ps, signum).sa_flags = SA_RESTART;
}
sigemptyset(&p->p_sigctx.ps_sigcatch);
p->p_flag &= ~P_NOCLDSTOP;
/*
* Reset stack state to the user stack.
*/
p->p_sigctx.ps_sigstk.ss_flags = SS_DISABLE;
p->p_sigctx.ps_sigstk.ss_size = 0;
p->p_sigctx.ps_sigstk.ss_sp = 0;
/* One reference. */
ps->sa_refcnt = 1;
}
/*
* Reset signals for an exec of the specified process.
*/
void
execsigs(struct proc *p)
{
struct sigacts *ps;
int signum, prop;
sigactsunshare(p);
ps = p->p_sigacts;
/*
* Reset caught signals. Held signals remain held
* through p_sigctx.ps_sigmask (unless they were caught,
* and are now ignored by default).
*/
for (signum = 1; signum < NSIG; signum++) {
if (sigismember(&p->p_sigctx.ps_sigcatch, signum)) {
prop = sigprop[signum];
if (prop & SA_IGNORE) {
if ((prop & SA_CONT) == 0)
sigaddset(&p->p_sigctx.ps_sigignore,
signum);
sigdelset(&p->p_sigctx.ps_siglist, signum);
}
SIGACTION_PS(ps, signum).sa_handler = SIG_DFL;
}
sigemptyset(&SIGACTION_PS(ps, signum).sa_mask);
SIGACTION_PS(ps, signum).sa_flags = SA_RESTART;
}
sigemptyset(&p->p_sigctx.ps_sigcatch);
p->p_flag &= ~P_NOCLDSTOP;
/*
* Reset stack state to the user stack.
*/
p->p_sigctx.ps_sigstk.ss_flags = SS_DISABLE;
p->p_sigctx.ps_sigstk.ss_size = 0;
p->p_sigctx.ps_sigstk.ss_sp = 0;
}
int
sigprocmask1(struct proc *p, int how, const sigset_t *nss, sigset_t *oss)
{
if (oss)
*oss = p->p_sigctx.ps_sigmask;
if (nss) {
(void)splsched(); /* XXXSMP */
switch (how) {
case SIG_BLOCK:
sigplusset(nss, &p->p_sigctx.ps_sigmask);
break;
case SIG_UNBLOCK:
sigminusset(nss, &p->p_sigctx.ps_sigmask);
CHECKSIGS(p);
break;
case SIG_SETMASK:
p->p_sigctx.ps_sigmask = *nss;
CHECKSIGS(p);
break;
default:
(void)spl0(); /* XXXSMP */
return (EINVAL);
}
sigminusset(&sigcantmask, &p->p_sigctx.ps_sigmask);
(void)spl0(); /* XXXSMP */
}
return (0);
}
/*
* Manipulate signal mask.
* Note that we receive new mask, not pointer,
* and return old mask as return value;
* the library stub does the rest.
*/
int
sys___sigprocmask14(struct proc *p, void *v, register_t *retval)
{
struct sys___sigprocmask14_args /* {
syscallarg(int) how;
syscallarg(const sigset_t *) set;
syscallarg(sigset_t *) oset;
} */ *uap = v;
sigset_t nss, oss;
int error;
if (SCARG(uap, set)) {
error = copyin(SCARG(uap, set), &nss, sizeof(nss));
if (error)
return (error);
}
error = sigprocmask1(p, SCARG(uap, how),
SCARG(uap, set) ? &nss : 0, SCARG(uap, oset) ? &oss : 0);
if (error)
return (error);
if (SCARG(uap, oset)) {
error = copyout(&oss, SCARG(uap, oset), sizeof(oss));
if (error)
return (error);
}
return (0);
}
void
sigpending1(struct proc *p, sigset_t *ss)
{
*ss = p->p_sigctx.ps_siglist;
sigminusset(&p->p_sigctx.ps_sigmask, ss);
}
/* ARGSUSED */
int
sys___sigpending14(struct proc *p, void *v, register_t *retval)
{
struct sys___sigpending14_args /* {
syscallarg(sigset_t *) set;
} */ *uap = v;
sigset_t ss;
sigpending1(p, &ss);
return (copyout(&ss, SCARG(uap, set), sizeof(ss)));
}
int
sigsuspend1(struct proc *p, const sigset_t *ss)
{
struct sigacts *ps;
ps = p->p_sigacts;
if (ss) {
/*
* When returning from sigpause, we want
* the old mask to be restored after the
* signal handler has finished. Thus, we
* save it here and mark the sigctx structure
* to indicate this.
*/
p->p_sigctx.ps_oldmask = p->p_sigctx.ps_sigmask;
p->p_sigctx.ps_flags |= SAS_OLDMASK;
(void) splsched(); /* XXXSMP */
p->p_sigctx.ps_sigmask = *ss;
CHECKSIGS(p);
sigminusset(&sigcantmask, &p->p_sigctx.ps_sigmask);
(void) spl0(); /* XXXSMP */
}
while (tsleep((caddr_t) ps, PPAUSE|PCATCH, "pause", 0) == 0)
/* void */;
/* always return EINTR rather than ERESTART... */
return (EINTR);
}
/*
* Suspend process until signal, providing mask to be set
* in the meantime. Note nonstandard calling convention:
* libc stub passes mask, not pointer, to save a copyin.
*/
/* ARGSUSED */
int
sys___sigsuspend14(struct proc *p, void *v, register_t *retval)
{
struct sys___sigsuspend14_args /* {
syscallarg(const sigset_t *) set;
} */ *uap = v;
sigset_t ss;
int error;
if (SCARG(uap, set)) {
error = copyin(SCARG(uap, set), &ss, sizeof(ss));
if (error)
return (error);
}
return (sigsuspend1(p, SCARG(uap, set) ? &ss : 0));
}
int
sigaltstack1(struct proc *p, const struct sigaltstack *nss,
struct sigaltstack *oss)
{
if (oss)
*oss = p->p_sigctx.ps_sigstk;
if (nss) {
if (nss->ss_flags & ~SS_ALLBITS)
return (EINVAL);
if (nss->ss_flags & SS_DISABLE) {
if (p->p_sigctx.ps_sigstk.ss_flags & SS_ONSTACK)
return (EINVAL);
} else {
if (nss->ss_size < MINSIGSTKSZ)
return (ENOMEM);
}
p->p_sigctx.ps_sigstk = *nss;
}
return (0);
}
/* ARGSUSED */
int
sys___sigaltstack14(struct proc *p, void *v, register_t *retval)
{
struct sys___sigaltstack14_args /* {
syscallarg(const struct sigaltstack *) nss;
syscallarg(struct sigaltstack *) oss;
} */ *uap = v;
struct sigaltstack nss, oss;
int error;
if (SCARG(uap, nss)) {
error = copyin(SCARG(uap, nss), &nss, sizeof(nss));
if (error)
return (error);
}
error = sigaltstack1(p,
SCARG(uap, nss) ? &nss : 0, SCARG(uap, oss) ? &oss : 0);
if (error)
return (error);
if (SCARG(uap, oss)) {
error = copyout(&oss, SCARG(uap, oss), sizeof(oss));
if (error)
return (error);
}
return (0);
}
/* ARGSUSED */
int
sys_kill(struct proc *cp, void *v, register_t *retval)
{
struct sys_kill_args /* {
syscallarg(int) pid;
syscallarg(int) signum;
} */ *uap = v;
struct proc *p;
struct pcred *pc;
pc = cp->p_cred;
if ((u_int)SCARG(uap, signum) >= NSIG)
return (EINVAL);
if (SCARG(uap, pid) > 0) {
/* kill single process */
if ((p = pfind(SCARG(uap, pid))) == NULL)
return (ESRCH);
if (!CANSIGNAL(cp, pc, p, SCARG(uap, signum)))
return (EPERM);
if (SCARG(uap, signum))
psignal(p, SCARG(uap, signum));
return (0);
}
switch (SCARG(uap, pid)) {
case -1: /* broadcast signal */
return (killpg1(cp, SCARG(uap, signum), 0, 1));
case 0: /* signal own process group */
return (killpg1(cp, SCARG(uap, signum), 0, 0));
default: /* negative explicit process group */
return (killpg1(cp, SCARG(uap, signum), -SCARG(uap, pid), 0));
}
/* NOTREACHED */
}
/*
* Common code for kill process group/broadcast kill.
* cp is calling process.
*/
int
killpg1(struct proc *cp, int signum, int pgid, int all)
{
struct proc *p;
struct pcred *pc;
struct pgrp *pgrp;
int nfound;
pc = cp->p_cred;
nfound = 0;
if (all) {
/*
* broadcast
*/
proclist_lock_read();
for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
p == cp || !CANSIGNAL(cp, pc, p, signum))
continue;
nfound++;
if (signum)
psignal(p, signum);
}
proclist_unlock_read();
} else {
if (pgid == 0)
/*
* zero pgid means send to my process group.
*/
pgrp = cp->p_pgrp;
else {
pgrp = pgfind(pgid);
if (pgrp == NULL)
return (ESRCH);
}
for (p = pgrp->pg_members.lh_first;
p != 0;
p = p->p_pglist.le_next) {
if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
!CANSIGNAL(cp, pc, p, signum))
continue;
nfound++;
if (signum && P_ZOMBIE(p) == 0)
psignal(p, signum);
}
}
return (nfound ? 0 : ESRCH);
}
/*
* Send a signal to a process group.
*/
void
gsignal(int pgid, int 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(struct pgrp *pgrp, int signum, int checkctty)
{
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(struct proc *p, int signum, u_long code)
{
struct sigacts *ps;
ps = p->p_sigacts;
if ((p->p_flag & P_TRACED) == 0 &&
sigismember(&p->p_sigctx.ps_sigcatch, signum) &&
!sigismember(&p->p_sigctx.ps_sigmask, signum)) {
p->p_stats->p_ru.ru_nsignals++;
#ifdef KTRACE
if (KTRPOINT(p, KTR_PSIG))
ktrpsig(p, signum,
SIGACTION_PS(ps, signum).sa_handler,
&p->p_sigctx.ps_sigmask, code);
#endif
(*p->p_emul->e_sendsig)(SIGACTION_PS(ps, signum).sa_handler,
signum, &p->p_sigctx.ps_sigmask, code);
(void) splsched(); /* XXXSMP */
sigplusset(&SIGACTION_PS(ps, signum).sa_mask,
&p->p_sigctx.ps_sigmask);
if (SIGACTION_PS(ps, signum).sa_flags & SA_RESETHAND) {
sigdelset(&p->p_sigctx.ps_sigcatch, signum);
if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
sigaddset(&p->p_sigctx.ps_sigignore, signum);
SIGACTION_PS(ps, signum).sa_handler = SIG_DFL;
}
(void) spl0(); /* XXXSMP */
} else {
p->p_sigctx.ps_code = code; /* XXX for core dump/debugger */
p->p_sigctx.ps_sig = signum; /* XXX to verify code */
psignal(p, signum);
}
}
/*
* Send the signal to the process. If the signal has an action, the action
* is usually performed by the target process rather than the caller; we add
* the signal to the set of pending signals for the process.
*
* Exceptions:
* o When a stop signal is sent to a sleeping process that takes the
* default action, the process is stopped without awakening it.
* o SIGCONT restarts stopped processes (or puts them back to sleep)
* regardless of the signal action (eg, blocked or ignored).
*
* Other ignored signals are discarded immediately.
*
* XXXSMP: Invoked as psignal() or sched_psignal().
*/
void
psignal1(struct proc *p, int signum,
int dolock) /* XXXSMP: works, but icky */
{
int s, prop;
sig_t action;
#ifdef DIAGNOSTIC
if (signum <= 0 || signum >= NSIG)
panic("psignal signal number");
/* XXXSMP: works, but icky */
if (dolock)
SCHED_ASSERT_UNLOCKED();
else
SCHED_ASSERT_LOCKED();
#endif
prop = sigprop[signum];
/*
* If proc is traced, always give parent a chance.
*/
if (p->p_flag & P_TRACED)
action = SIG_DFL;
else {
/*
* If the signal is being ignored,
* then we forget about it immediately.
* (Note: we don't set SIGCONT in p_sigctx.ps_sigignore,
* and if it is set to SIG_IGN,
* action will be SIG_DFL here.)
*/
if (sigismember(&p->p_sigctx.ps_sigignore, signum))
return;
if (sigismember(&p->p_sigctx.ps_sigmask, signum))
action = SIG_HOLD;
else if (sigismember(&p->p_sigctx.ps_sigcatch, signum))
action = SIG_CATCH;
else {
action = SIG_DFL;
if (prop & SA_KILL && p->p_nice > NZERO)
p->p_nice = NZERO;
/*
* If sending a tty stop signal to a member of an
* orphaned process group, discard the signal here if
* the action is default; don't stop the process below
* if sleeping, and don't clear any pending SIGCONT.
*/
if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0)
return;
}
}
if (prop & SA_CONT)
sigminusset(&stopsigmask, &p->p_sigctx.ps_siglist);
if (prop & SA_STOP)
sigminusset(&contsigmask, &p->p_sigctx.ps_siglist);
sigaddset(&p->p_sigctx.ps_siglist, signum);
/* CHECKSIGS() is "inlined" here. */
p->p_sigctx.ps_sigcheck = 1;
/*
* Defer further processing for signals which are held,
* except that stopped processes must be continued by SIGCONT.
*/
if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP))
return;
/* XXXSMP: works, but icky */
if (dolock)
SCHED_LOCK(s);
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_sigctx.ps_siglist, signum);
goto out;
}
/*
* When a sleeping process receives a stop
* signal, process immediately if possible.
*/
if ((prop & SA_STOP) && action == SIG_DFL) {
/*
* If a child holding parent blocked,
* stopping could cause deadlock.
*/
if (p->p_flag & P_PPWAIT)
goto out;
sigdelset(&p->p_sigctx.ps_siglist, signum);
p->p_xstat = signum;
if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) {
/*
* XXXSMP: recursive call; don't lock
* the second time around.
*/
sched_psignal(p->p_pptr, SIGCHLD);
}
proc_stop(p); /* XXXSMP: recurse? */
goto out;
}
/*
* All other (caught or default) signals
* cause the process to run.
*/
goto runfast;
/*NOTREACHED*/
case SSTOP:
/*
* If traced process is already stopped,
* then no further action is necessary.
*/
if (p->p_flag & P_TRACED)
goto out;
/*
* Kill signal always sets processes running.
*/
if (signum == SIGKILL)
goto runfast;
if (prop & SA_CONT) {
/*
* If SIGCONT is default (or ignored), we continue the
* process but don't leave the signal in p_sigctx.ps_siglist, as
* it has no further action. If SIGCONT is held, we
* continue the process and leave the signal in
* p_sigctx.ps_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_sigctx.ps_siglist, signum);
if (action == SIG_CATCH)
goto runfast;
if (p->p_wchan == 0)
goto run;
p->p_stat = SSLEEP;
goto out;
}
if (prop & SA_STOP) {
/*
* Already stopped, don't need to stop again.
* (If we did the shell could get confused.)
*/
sigdelset(&p->p_sigctx.ps_siglist, signum);
goto out;
}
/*
* If process is sleeping interruptibly, then simulate a
* wakeup so that when it is continued, it will be made
* runnable and can look at the signal. But don't make
* the process runnable, leave it stopped.
*/
if (p->p_wchan && p->p_flag & P_SINTR)
unsleep(p);
goto out;
#ifdef __HAVE_AST_PERPROC
case SONPROC:
case SRUN:
case SIDL:
/*
* SONPROC: We're running, notice the signal when
* we return back to userspace.
*
* SRUN, SIDL: Notice the signal when we run again
* and return to back to userspace.
*/
signotify(p);
goto out;
default:
/*
* SDEAD, SZOMB: The signal will never be noticed.
*/
goto out;
#else /* ! __HAVE_AST_PERPROC */
case SONPROC:
/*
* We're running; notice the signal.
*/
signotify(p);
goto out;
default:
/*
* SRUN, SIDL, SDEAD, SZOMB do nothing with the signal.
* It will either never be noticed, or noticed very soon.
*/
goto out;
#endif /* __HAVE_AST_PERPROC */
}
/*NOTREACHED*/
runfast:
/*
* Raise priority to at least PUSER.
*/
if (p->p_priority > PUSER)
p->p_priority = PUSER;
run:
setrunnable(p); /* XXXSMP: recurse? */
out:
/* XXXSMP: works, but icky */
if (dolock)
SCHED_UNLOCK(s);
}
static __inline int firstsig(const sigset_t *);
static __inline int
firstsig(const sigset_t *ss)
{
int sig;
sig = ffs(ss->__bits[0]);
if (sig != 0)
return (sig);
#if NSIG > 33
sig = ffs(ss->__bits[1]);
if (sig != 0)
return (sig + 32);
#endif
#if NSIG > 65
sig = ffs(ss->__bits[2]);
if (sig != 0)
return (sig + 64);
#endif
#if NSIG > 97
sig = ffs(ss->__bits[3]);
if (sig != 0)
return (sig + 96);
#endif
return (0);
}
/*
* If the current process has received a signal (should be caught or cause
* termination, should interrupt current syscall), return the signal number.
* Stop signals with default action are processed immediately, then cleared;
* they aren't returned. This is checked after each entry to the system for
* a syscall or trap (though this can usually be done without calling issignal
* by checking the pending signal masks in the CURSIG macro.) The normal call
* sequence is
*
* while (signum = CURSIG(curproc))
* postsig(signum);
*/
int
issignal(struct proc *p)
{
int s, signum, prop;
sigset_t ss;
for (;;) {
sigpending1(p, &ss);
if (p->p_flag & P_PPWAIT)
sigminusset(&stopsigmask, &ss);
signum = firstsig(&ss);
if (signum == 0) { /* no signal to send */
p->p_sigctx.ps_sigcheck = 0;
return (0);
}
/* take the signal! */
sigdelset(&p->p_sigctx.ps_siglist, signum);
/*
* We should see pending but ignored signals
* only if P_TRACED was on when they were posted.
*/
if (sigismember(&p->p_sigctx.ps_sigignore, signum) &&
(p->p_flag & P_TRACED) == 0)
continue;
if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) {
/*
* If traced, always stop, and stay
* stopped until released by the debugger.
*/
p->p_xstat = signum;
if ((p->p_flag & P_FSTRACE) == 0)
psignal(p->p_pptr, SIGCHLD);
SCHED_LOCK(s);
proc_stop(p);
mi_switch(p);
SCHED_ASSERT_UNLOCKED();
splx(s);
/*
* If we are no longer being traced, or the parent
* didn't give us a signal, look for more signals.
*/
if ((p->p_flag & P_TRACED) == 0 || p->p_xstat == 0)
continue;
/*
* If the new signal is being masked, look for other
* signals.
*/
signum = p->p_xstat;
/*
* `p->p_sigctx.ps_siglist |= mask' is done
* in setrunnable().
*/
if (sigismember(&p->p_sigctx.ps_sigmask, signum))
continue;
/* take the signal! */
sigdelset(&p->p_sigctx.ps_siglist, signum);
}
prop = sigprop[signum];
/*
* Decide whether the signal should be returned.
* Return the signal's number, or fall through
* to clear it from the pending mask.
*/
switch ((long)SIGACTION(p, signum).sa_handler) {
case (long)SIG_DFL:
/*
* Don't take default actions on system processes.
*/
if (p->p_pid <= 1) {
#ifdef DIAGNOSTIC
/*
* Are you sure you want to ignore SIGSEGV
* in init? XXX
*/
printf("Process (pid %d) got signal %d\n",
p->p_pid, signum);
#endif
break; /* == ignore */
}
/*
* If there is a pending stop signal to process
* with default action, stop here,
* then clear the signal. However,
* if process is member of an orphaned
* process group, ignore tty stop signals.
*/
if (prop & SA_STOP) {
if (p->p_flag & P_TRACED ||
(p->p_pgrp->pg_jobc == 0 &&
prop & SA_TTYSTOP))
break; /* == ignore */
p->p_xstat = signum;
if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0)
psignal(p->p_pptr, SIGCHLD);
SCHED_LOCK(s);
proc_stop(p);
mi_switch(p);
SCHED_ASSERT_UNLOCKED();
splx(s);
break;
} else if (prop & SA_IGNORE) {
/*
* Except for SIGCONT, shouldn't get here.
* Default action is to ignore; drop it.
*/
break; /* == ignore */
} else
goto keep;
/*NOTREACHED*/
case (long)SIG_IGN:
/*
* Masking above should prevent us ever trying
* to take action on an ignored signal other
* than SIGCONT, unless process is traced.
*/
if ((prop & SA_CONT) == 0 &&
(p->p_flag & P_TRACED) == 0)
printf("issignal\n");
break; /* == ignore */
default:
/*
* This signal has an action, let
* postsig() process it.
*/
goto keep;
}
}
/* NOTREACHED */
keep:
/* leave the signal for later */
sigaddset(&p->p_sigctx.ps_siglist, signum);
CHECKSIGS(p);
return (signum);
}
/*
* Put the argument process into the stopped state and notify the parent
* via wakeup. Signals are handled elsewhere. The process must not be
* on the run queue.
*/
static void
proc_stop(struct proc *p)
{
SCHED_ASSERT_LOCKED();
p->p_stat = SSTOP;
p->p_flag &= ~P_WAITED;
sched_wakeup((caddr_t)p->p_pptr);
}
/*
* Take the action for the specified signal
* from the current set of pending signals.
*/
void
postsig(int signum)
{
struct proc *p;
struct sigacts *ps;
sig_t action;
u_long code;
sigset_t *returnmask;
p = curproc;
ps = p->p_sigacts;
#ifdef DIAGNOSTIC
if (signum == 0)
panic("postsig");
#endif
KERNEL_PROC_LOCK(p);
sigdelset(&p->p_sigctx.ps_siglist, signum);
action = SIGACTION_PS(ps, signum).sa_handler;
#ifdef KTRACE
if (KTRPOINT(p, KTR_PSIG))
ktrpsig(p,
signum, action, p->p_sigctx.ps_flags & SAS_OLDMASK ?
&p->p_sigctx.ps_oldmask : &p->p_sigctx.ps_sigmask, 0);
#endif
if (action == SIG_DFL) {
/*
* Default action, where the default is to kill
* the process. (Other cases were ignored above.)
*/
sigexit(p, signum);
/* NOTREACHED */
} else {
/*
* If we get here, the signal must be caught.
*/
#ifdef DIAGNOSTIC
if (action == SIG_IGN ||
sigismember(&p->p_sigctx.ps_sigmask, signum))
panic("postsig action");
#endif
/*
* Set the new mask value and also defer further
* occurences of this signal.
*
* Special case: user has done a sigpause. Here the
* current mask is not of interest, but rather the
* mask from before the sigpause is what we want
* restored after the signal processing is completed.
*/
if (p->p_sigctx.ps_flags & SAS_OLDMASK) {
returnmask = &p->p_sigctx.ps_oldmask;
p->p_sigctx.ps_flags &= ~SAS_OLDMASK;
} else
returnmask = &p->p_sigctx.ps_sigmask;
p->p_stats->p_ru.ru_nsignals++;
if (p->p_sigctx.ps_sig != signum) {
code = 0;
} else {
code = p->p_sigctx.ps_code;
p->p_sigctx.ps_code = 0;
p->p_sigctx.ps_sig = 0;
}
(*p->p_emul->e_sendsig)(action, signum, returnmask, code);
(void) splsched(); /* XXXSMP */
sigplusset(&SIGACTION_PS(ps, signum).sa_mask,
&p->p_sigctx.ps_sigmask);
if (SIGACTION_PS(ps, signum).sa_flags & SA_RESETHAND) {
sigdelset(&p->p_sigctx.ps_sigcatch, signum);
if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
sigaddset(&p->p_sigctx.ps_sigignore, signum);
SIGACTION_PS(ps, signum).sa_handler = SIG_DFL;
}
(void) spl0(); /* XXXSMP */
}
KERNEL_PROC_UNLOCK(p);
}
/*
* Kill the current process for stated reason.
*/
void
killproc(struct proc *p, char *why)
{
log(LOG_ERR, "pid %d was killed: %s\n", p->p_pid, why);
uprintf("sorry, pid %d was killed: %s\n", p->p_pid, why);
psignal(p, SIGKILL);
}
/*
* Force the current process to exit with the specified signal, dumping core
* if appropriate. We bypass the normal tests for masked and caught signals,
* allowing unrecoverable failures to terminate the process without changing
* signal state. Mark the accounting record with the signal termination.
* If dumping core, save the signal number for the debugger. Calls exit and
* does not return.
*/
#if defined(DEBUG)
int kern_logsigexit = 1; /* not static to make public for sysctl */
#else
int kern_logsigexit = 0; /* not static to make public for sysctl */
#endif
static const char logcoredump[] =
"pid %d (%s), uid %d: exited on signal %d (core dumped)\n";
static const char lognocoredump[] =
"pid %d (%s), uid %d: exited on signal %d (core not dumped, err = %d)\n";
void
sigexit(struct proc *p, int signum)
{
int error, exitsig;
exitsig = signum;
p->p_acflag |= AXSIG;
if (sigprop[signum] & SA_CORE) {
p->p_sigctx.ps_sig = signum;
if ((error = coredump(p)) == 0)
exitsig |= WCOREFLAG;
if (kern_logsigexit) {
int uid = p->p_cred && p->p_ucred ?
p->p_ucred->cr_uid : -1;
if (error)
log(LOG_INFO, lognocoredump, p->p_pid,
p->p_comm, uid, signum, error);
else
log(LOG_INFO, logcoredump, p->p_pid,
p->p_comm, uid, signum);
}
}
exit1(p, W_EXITCODE(0, exitsig));
/* NOTREACHED */
}
/*
* Dump core, into a file named "progname.core" or "core" (depending on the
* value of shortcorename), unless the process was setuid/setgid.
*/
int
coredump(struct proc *p)
{
struct vnode *vp;
struct vmspace *vm;
struct ucred *cred;
struct nameidata nd;
struct vattr vattr;
int error, error1;
char name[MAXPATHLEN];
struct core core;
vm = p->p_vmspace;
cred = p->p_cred->pc_ucred;
/*
* Make sure the process has not set-id, to prevent data leaks.
*/
if (p->p_flag & P_SUGID)
return (EPERM);
/*
* Refuse to core if the data + stack + user size is larger than
* the core dump limit. XXX THIS IS WRONG, because of mapped
* data.
*/
if (USPACE + ctob(vm->vm_dsize + vm->vm_ssize) >=
p->p_rlimit[RLIMIT_CORE].rlim_cur)
return (EFBIG); /* better error code? */
/*
* The core dump will go in the current working directory. Make
* sure that the directory is still there and that the mount flags
* allow us to write core dumps there.
*/
vp = p->p_cwdi->cwdi_cdir;
if (vp->v_mount == NULL ||
(vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0)
return (EPERM);
error = build_corename(p, name);
if (error)
return error;
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p);
error = vn_open(&nd, O_CREAT | FWRITE | FNOSYMLINK, S_IRUSR | S_IWUSR);
if (error)
return (error);
vp = nd.ni_vp;
/* Don't dump to non-regular files or files with links. */
if (vp->v_type != VREG ||
VOP_GETATTR(vp, &vattr, cred, p) || vattr.va_nlink != 1) {
error = EINVAL;
goto out;
}
VATTR_NULL(&vattr);
vattr.va_size = 0;
VOP_LEASE(vp, p, cred, LEASE_WRITE);
VOP_SETATTR(vp, &vattr, cred, p);
p->p_acflag |= ACORE;
if ((p->p_flag & P_32) && coredump32_hook != NULL)
return (*coredump32_hook)(p, vp);
#if 0
/*
* XXX
* It would be nice if we at least dumped the signal state (and made it
* available at run time to the debugger, as well), but this code
* hasn't actually had any effect for a long time, since we don't dump
* the user area. For now, it's dead.
*/
memcpy(&p->p_addr->u_kproc.kp_proc, p, sizeof(struct proc));
fill_eproc(p, &p->p_addr->u_kproc.kp_eproc);
#endif
core.c_midmag = 0;
strncpy(core.c_name, p->p_comm, MAXCOMLEN);
core.c_nseg = 0;
core.c_signo = p->p_sigctx.ps_sig;
core.c_ucode = p->p_sigctx.ps_code;
core.c_cpusize = 0;
core.c_tsize = (u_long)ctob(vm->vm_tsize);
core.c_dsize = (u_long)ctob(vm->vm_dsize);
core.c_ssize = (u_long)round_page(ctob(vm->vm_ssize));
error = cpu_coredump(p, vp, cred, &core);
if (error)
goto out;
/*
* uvm_coredump() spits out all appropriate segments.
* All that's left to do is to write the core header.
*/
error = uvm_coredump(p, vp, cred, &core);
if (error)
goto out;
error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&core,
(int)core.c_hdrsize, (off_t)0,
UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, NULL, p);
out:
VOP_UNLOCK(vp, 0);
error1 = vn_close(vp, FWRITE, cred, p);
if (error == 0)
error = error1;
return (error);
}
/*
* Nonexistent system call-- signal process (may want to handle it).
* Flag error in case process won't see signal immediately (blocked or ignored).
*/
/* ARGSUSED */
int
sys_nosys(struct proc *p, void *v, register_t *retval)
{
psignal(p, SIGSYS);
return (ENOSYS);
}
static int
build_corename(struct proc *p, char dst[MAXPATHLEN])
{
const char *s;
char *d, *end;
int i;
for (s = p->p_limit->pl_corename, d = dst, end = d + MAXPATHLEN;
*s != '\0'; s++) {
if (*s == '%') {
switch (*(s + 1)) {
case 'n':
i = snprintf(d, end - d, "%s", p->p_comm);
break;
case 'p':
i = snprintf(d, end - d, "%d", p->p_pid);
break;
case 'u':
i = snprintf(d, end - d, "%s",
p->p_pgrp->pg_session->s_login);
break;
case 't':
i = snprintf(d, end - d, "%ld",
p->p_stats->p_start.tv_sec);
break;
default:
goto copy;
}
d += i;
s++;
} else {
copy: *d = *s;
d++;
}
if (d >= end)
return (ENAMETOOLONG);
}
*d = '\0';
return (0);
}
/*
* Returns true if signal is ignored or masked for passed process.
*/
int
sigismasked(struct proc *p, int sig)
{
return sigismember(&p->p_sigctx.ps_sigignore, SIGTTOU)
|| sigismember(&p->p_sigctx.ps_sigmask, SIGTTOU);
}
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