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NetBSD/sys/kern/kern_sig.c

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/* $NetBSD: kern_sig.c,v 1.201 2005/01/09 19:22:55 christos 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. 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.201 2005/01/09 19:22:55 christos Exp $");
#include "opt_ktrace.h"
#include "opt_compat_sunos.h"
#include "opt_compat_netbsd.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/ucontext.h>
#include <sys/sa.h>
#include <sys/savar.h>
#include <sys/exec.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <machine/cpu.h>
#include <sys/user.h> /* for coredump */
#include <uvm/uvm.h>
#include <uvm/uvm_extern.h>
static void child_psignal(struct proc *, int);
static int build_corename(struct proc *, char *, const char *, size_t);
static void ksiginfo_exithook(struct proc *, void *);
static void ksiginfo_put(struct proc *, const ksiginfo_t *);
static ksiginfo_t *ksiginfo_get(struct proc *, int);
static void kpsignal2(struct proc *, const ksiginfo_t *, int);
sigset_t contsigmask, stopsigmask, sigcantmask;
struct pool sigacts_pool; /* memory pool for sigacts structures */
/*
* struct sigacts memory pool allocator.
*/
static void *
sigacts_poolpage_alloc(struct pool *pp, int flags)
{
return (void *)uvm_km_kmemalloc1(kernel_map,
uvm.kernel_object, (PAGE_SIZE)*2, (PAGE_SIZE)*2, UVM_UNKNOWN_OFFSET,
(flags & PR_WAITOK) ? 0 : UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK);
}
static void
sigacts_poolpage_free(struct pool *pp, void *v)
{
uvm_km_free(kernel_map, (vaddr_t)v, (PAGE_SIZE)*2);
}
static struct pool_allocator sigactspool_allocator = {
sigacts_poolpage_alloc, sigacts_poolpage_free,
};
POOL_INIT(siginfo_pool, sizeof(siginfo_t), 0, 0, 0, "siginfo",
&pool_allocator_nointr);
POOL_INIT(ksiginfo_pool, sizeof(ksiginfo_t), 0, 0, 0, "ksiginfo", NULL);
/*
* 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))
/*
* Remove and return the first ksiginfo element that matches our requested
* signal, or return NULL if one not found.
*/
static ksiginfo_t *
ksiginfo_get(struct proc *p, int signo)
{
ksiginfo_t *ksi;
int s;
s = splsoftclock();
simple_lock(&p->p_sigctx.ps_silock);
CIRCLEQ_FOREACH(ksi, &p->p_sigctx.ps_siginfo, ksi_list) {
if (ksi->ksi_signo == signo) {
CIRCLEQ_REMOVE(&p->p_sigctx.ps_siginfo, ksi, ksi_list);
goto out;
}
}
ksi = NULL;
out:
simple_unlock(&p->p_sigctx.ps_silock);
splx(s);
return ksi;
}
/*
* Append a new ksiginfo element to the list of pending ksiginfo's, if
* we need to (SA_SIGINFO was requested). We replace non RT signals if
* they already existed in the queue and we add new entries for RT signals,
* or for non RT signals with non-existing entries.
*/
static void
ksiginfo_put(struct proc *p, const ksiginfo_t *ksi)
{
ksiginfo_t *kp;
struct sigaction *sa = &SIGACTION_PS(p->p_sigacts, ksi->ksi_signo);
int s;
if ((sa->sa_flags & SA_SIGINFO) == 0)
return;
/*
* If there's no info, don't save it.
*/
if (KSI_EMPTY_P(ksi))
return;
s = splsoftclock();
simple_lock(&p->p_sigctx.ps_silock);
#ifdef notyet /* XXX: QUEUING */
if (ksi->ksi_signo < SIGRTMIN)
#endif
{
CIRCLEQ_FOREACH(kp, &p->p_sigctx.ps_siginfo, ksi_list) {
if (kp->ksi_signo == ksi->ksi_signo) {
KSI_COPY(ksi, kp);
goto out;
}
}
}
kp = pool_get(&ksiginfo_pool, PR_NOWAIT);
if (kp == NULL) {
#ifdef DIAGNOSTIC
printf("Out of memory allocating siginfo for pid %d\n",
p->p_pid);
#endif
goto out;
}
*kp = *ksi;
CIRCLEQ_INSERT_TAIL(&p->p_sigctx.ps_siginfo, kp, ksi_list);
out:
simple_unlock(&p->p_sigctx.ps_silock);
splx(s);
}
/*
* free all pending ksiginfo on exit
*/
static void
ksiginfo_exithook(struct proc *p, void *v)
{
int s;
s = splsoftclock();
simple_lock(&p->p_sigctx.ps_silock);
while (!CIRCLEQ_EMPTY(&p->p_sigctx.ps_siginfo)) {
ksiginfo_t *ksi = CIRCLEQ_FIRST(&p->p_sigctx.ps_siginfo);
CIRCLEQ_REMOVE(&p->p_sigctx.ps_siginfo, ksi, ksi_list);
pool_put(&ksiginfo_pool, ksi);
}
simple_unlock(&p->p_sigctx.ps_silock);
splx(s);
}
/*
* Initialize signal-related data structures.
*/
void
signal_init(void)
{
sigactspool_allocator.pa_pagesz = (PAGE_SIZE)*2;
pool_init(&sigacts_pool, sizeof(struct sigacts), 0, 0, 0, "sigapl",
sizeof(struct sigacts) > PAGE_SIZE ?
&sigactspool_allocator : &pool_allocator_nointr);
exithook_establish(ksiginfo_exithook, NULL);
exechook_establish(ksiginfo_exithook, NULL);
}
/*
* 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 sigacts *ps)
{
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, const void *tramp, int vers)
{
struct sigacts *ps;
int prop;
ps = p->p_sigacts;
if (signum <= 0 || signum >= NSIG)
return (EINVAL);
/*
* Trampoline ABI version 0 is reserved for the legacy
* kernel-provided on-stack trampoline. Conversely, if we are
* using a non-0 ABI version, we must have a trampoline. Only
* validate the vers if a new sigaction was supplied. Emulations
* use legacy kernel trampolines with version 0, alternatively
* check for that too.
*/
if ((vers != 0 && tramp == NULL) ||
#ifdef SIGTRAMP_VALID
(nsa != NULL &&
((vers == 0) ?
(p->p_emul->e_sigcode == NULL) :
!SIGTRAMP_VALID(vers))) ||
#endif
(vers == 0 && tramp != NULL))
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;
ps->sa_sigdesc[signum].sd_tramp = tramp;
ps->sa_sigdesc[signum].sd_vers = vers;
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);
}
#ifdef COMPAT_16
/* ARGSUSED */
int
compat_16_sys___sigaction14(struct lwp *l, void *v, register_t *retval)
{
struct compat_16_sys___sigaction14_args /* {
syscallarg(int) signum;
syscallarg(const struct sigaction *) nsa;
syscallarg(struct sigaction *) osa;
} */ *uap = v;
struct proc *p;
struct sigaction nsa, osa;
int error;
if (SCARG(uap, nsa)) {
error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa));
if (error)
return (error);
}
p = l->l_proc;
error = sigaction1(p, SCARG(uap, signum),
SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0,
NULL, 0);
if (error)
return (error);
if (SCARG(uap, osa)) {
error = copyout(&osa, SCARG(uap, osa), sizeof(osa));
if (error)
return (error);
}
return (0);
}
#endif
/* ARGSUSED */
int
sys___sigaction_sigtramp(struct lwp *l, void *v, register_t *retval)
{
struct sys___sigaction_sigtramp_args /* {
syscallarg(int) signum;
syscallarg(const struct sigaction *) nsa;
syscallarg(struct sigaction *) osa;
syscallarg(void *) tramp;
syscallarg(int) vers;
} */ *uap = v;
struct proc *p = l->l_proc;
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,
SCARG(uap, tramp), SCARG(uap, vers));
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_sigctx.ps_sigwaited = NULL;
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_sigctx.ps_sigwaited = NULL;
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 lwp *l, void *v, register_t *retval)
{
struct sys___sigprocmask14_args /* {
syscallarg(int) how;
syscallarg(const sigset_t *) set;
syscallarg(sigset_t *) oset;
} */ *uap = v;
struct proc *p;
sigset_t nss, oss;
int error;
if (SCARG(uap, set)) {
error = copyin(SCARG(uap, set), &nss, sizeof(nss));
if (error)
return (error);
}
p = l->l_proc;
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 lwp *l, void *v, register_t *retval)
{
struct sys___sigpending14_args /* {
syscallarg(sigset_t *) set;
} */ *uap = v;
struct proc *p;
sigset_t ss;
p = l->l_proc;
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 lwp *l, void *v, register_t *retval)
{
struct sys___sigsuspend14_args /* {
syscallarg(const sigset_t *) set;
} */ *uap = v;
struct proc *p;
sigset_t ss;
int error;
if (SCARG(uap, set)) {
error = copyin(SCARG(uap, set), &ss, sizeof(ss));
if (error)
return (error);
}
p = l->l_proc;
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 lwp *l, void *v, register_t *retval)
{
struct sys___sigaltstack14_args /* {
syscallarg(const struct sigaltstack *) nss;
syscallarg(struct sigaltstack *) oss;
} */ *uap = v;
struct proc *p;
struct sigaltstack nss, oss;
int error;
if (SCARG(uap, nss)) {
error = copyin(SCARG(uap, nss), &nss, sizeof(nss));
if (error)
return (error);
}
p = l->l_proc;
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 lwp *l, void *v, register_t *retval)
{
struct sys_kill_args /* {
syscallarg(int) pid;
syscallarg(int) signum;
} */ *uap = v;
struct proc *cp, *p;
struct pcred *pc;
ksiginfo_t ksi;
cp = l->l_proc;
pc = cp->p_cred;
if ((u_int)SCARG(uap, signum) >= NSIG)
return (EINVAL);
KSI_INIT(&ksi);
ksi.ksi_signo = SCARG(uap, signum);
ksi.ksi_code = SI_USER;
ksi.ksi_pid = cp->p_pid;
ksi.ksi_uid = cp->p_ucred->cr_uid;
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))
kpsignal2(p, &ksi, 1);
return (0);
}
switch (SCARG(uap, pid)) {
case -1: /* broadcast signal */
return (killpg1(cp, &ksi, 0, 1));
case 0: /* signal own process group */
return (killpg1(cp, &ksi, 0, 0));
default: /* negative explicit process group */
return (killpg1(cp, &ksi, -SCARG(uap, pid), 0));
}
/* NOTREACHED */
}
/*
* Common code for kill process group/broadcast kill.
* cp is calling process.
*/
int
killpg1(struct proc *cp, ksiginfo_t *ksi, int pgid, int all)
{
struct proc *p;
struct pcred *pc;
struct pgrp *pgrp;
int nfound;
int signum = ksi->ksi_signo;
pc = cp->p_cred;
nfound = 0;
if (all) {
/*
* broadcast
*/
proclist_lock_read();
PROCLIST_FOREACH(p, &allproc) {
if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
p == cp || !CANSIGNAL(cp, pc, p, signum))
continue;
nfound++;
if (signum)
kpsignal2(p, ksi, 1);
}
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);
}
LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
!CANSIGNAL(cp, pc, p, signum))
continue;
nfound++;
if (signum && P_ZOMBIE(p) == 0)
kpsignal2(p, ksi, 1);
}
}
return (nfound ? 0 : ESRCH);
}
/*
* Send a signal to a process group.
*/
void
gsignal(int pgid, int signum)
{
ksiginfo_t ksi;
KSI_INIT_EMPTY(&ksi);
ksi.ksi_signo = signum;
kgsignal(pgid, &ksi, NULL);
}
void
kgsignal(int pgid, ksiginfo_t *ksi, void *data)
{
struct pgrp *pgrp;
if (pgid && (pgrp = pgfind(pgid)))
kpgsignal(pgrp, ksi, data, 0);
}
/*
* Send a signal to a process group. If checktty is 1,
* limit to members which have a controlling terminal.
*/
void
pgsignal(struct pgrp *pgrp, int sig, int checkctty)
{
ksiginfo_t ksi;
KSI_INIT_EMPTY(&ksi);
ksi.ksi_signo = sig;
kpgsignal(pgrp, &ksi, NULL, checkctty);
}
void
kpgsignal(struct pgrp *pgrp, ksiginfo_t *ksi, void *data, int checkctty)
{
struct proc *p;
if (pgrp)
LIST_FOREACH(p, &pgrp->pg_members, p_pglist)
if (checkctty == 0 || p->p_flag & P_CONTROLT)
kpsignal(p, ksi, data);
}
/*
* 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 lwp *l, const ksiginfo_t *ksi)
{
struct proc *p;
struct sigacts *ps;
int signum = ksi->ksi_signo;
KASSERT(KSI_TRAP_P(ksi));
p = l->l_proc;
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, ksi);
#endif
kpsendsig(l, ksi, &p->p_sigctx.ps_sigmask);
(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_lwp = l->l_lid;
/* XXX for core dump/debugger */
p->p_sigctx.ps_signo = ksi->ksi_signo;
p->p_sigctx.ps_code = ksi->ksi_trap;
kpsignal2(p, ksi, 1);
}
}
/*
* Fill in signal information and signal the parent for a child status change.
*/
static void
child_psignal(struct proc *p, int dolock)
{
ksiginfo_t ksi;
KSI_INIT(&ksi);
ksi.ksi_signo = SIGCHLD;
ksi.ksi_code = p->p_xstat == SIGCONT ? CLD_CONTINUED : CLD_STOPPED;
ksi.ksi_pid = p->p_pid;
ksi.ksi_uid = p->p_ucred->cr_uid;
ksi.ksi_status = p->p_xstat;
ksi.ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec;
ksi.ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec;
kpsignal2(p->p_pptr, &ksi, dolock);
}
/*
* 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)
{
ksiginfo_t ksi;
KSI_INIT_EMPTY(&ksi);
ksi.ksi_signo = signum;
kpsignal2(p, &ksi, dolock);
}
void
kpsignal1(struct proc *p, ksiginfo_t *ksi, void *data, int dolock)
{
if ((p->p_flag & P_WEXIT) == 0 && data) {
size_t fd;
struct filedesc *fdp = p->p_fd;
ksi->ksi_fd = -1;
for (fd = 0; fd < fdp->fd_nfiles; fd++) {
struct file *fp = fdp->fd_ofiles[fd];
/* XXX: lock? */
if (fp && fp->f_data == data) {
ksi->ksi_fd = fd;
break;
}
}
}
kpsignal2(p, ksi, dolock);
}
static void
kpsignal2(struct proc *p, const ksiginfo_t *ksi, int dolock)
{
struct lwp *l, *suspended = NULL;
struct sadata_vp *vp;
int s = 0, prop, allsusp;
sig_t action;
int signum = ksi->ksi_signo;
#ifdef DIAGNOSTIC
if (signum <= 0 || signum >= NSIG)
panic("psignal signal number %d", signum);
/* XXXSMP: works, but icky */
if (dolock)
SCHED_ASSERT_UNLOCKED();
else
SCHED_ASSERT_LOCKED();
#endif
/*
* Notify any interested parties in the signal.
*/
KNOTE(&p->p_klist, NOTE_SIGNAL | signum);
prop = sigprop[signum];
/*
* If proc is traced, always give parent a chance.
*/
if (p->p_flag & P_TRACED) {
action = SIG_DFL;
/*
* If the process is being traced and the signal is being
* caught, make sure to save any ksiginfo.
*/
if (sigismember(&p->p_sigctx.ps_sigcatch, signum))
ksiginfo_put(p, ksi);
} else {
/*
* If the signal was the result of a trap, reset it
* to default action if it's currently masked, so that it would
* coredump immediatelly instead of spinning repeatedly
* taking the signal.
*/
if (KSI_TRAP_P(ksi)
&& sigismember(&p->p_sigctx.ps_sigmask, signum)
&& !sigismember(&p->p_sigctx.ps_sigcatch, signum)) {
sigdelset(&p->p_sigctx.ps_sigignore, signum);
sigdelset(&p->p_sigctx.ps_sigcatch, signum);
sigdelset(&p->p_sigctx.ps_sigmask, signum);
SIGACTION(p, signum).sa_handler = SIG_DFL;
}
/*
* 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);
/*
* If the signal doesn't have SA_CANTMASK (no override for SIGKILL,
* please!), check if anything waits on it. If yes, save the
* info into provided ps_sigwaited, and wake-up the waiter.
* The signal won't be processed further here.
*/
if ((prop & SA_CANTMASK) == 0
&& p->p_sigctx.ps_sigwaited
&& sigismember(p->p_sigctx.ps_sigwait, signum)
&& p->p_stat != SSTOP) {
p->p_sigctx.ps_sigwaited->ksi_info = ksi->ksi_info;
p->p_sigctx.ps_sigwaited = NULL;
if (dolock)
wakeup_one(&p->p_sigctx.ps_sigwait);
else
sched_wakeup(&p->p_sigctx.ps_sigwait);
return;
}
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)) {
ksiginfo_put(p, ksi);
return;
}
/* XXXSMP: works, but icky */
if (dolock)
SCHED_LOCK(s);
if (p->p_flag & P_SA) {
allsusp = 0;
l = NULL;
if (p->p_stat == SACTIVE) {
SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) {
l = vp->savp_lwp;
KDASSERT(l != NULL);
if (l->l_flag & L_SA_IDLE) {
/* wakeup idle LWP */
goto found;
/*NOTREACHED*/
} else if (l->l_flag & L_SA_YIELD) {
/* idle LWP is already waking up */
goto out;
/*NOTREACHED*/
}
}
SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) {
l = vp->savp_lwp;
if (l->l_stat == LSRUN ||
l->l_stat == LSONPROC) {
signotify(p);
goto out;
/*NOTREACHED*/
}
if (l->l_stat == LSSLEEP &&
l->l_flag & L_SINTR) {
/* ok to signal vp lwp */
} else
l = NULL;
}
if (l == NULL)
allsusp = 1;
} else if (p->p_stat == SSTOP) {
SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) {
l = vp->savp_lwp;
if (l->l_stat == LSSLEEP && (l->l_flag & L_SINTR) != 0)
break;
l = NULL;
}
}
} else if (p->p_nrlwps > 0 && (p->p_stat != SSTOP)) {
/*
* At least one LWP is running or on a run queue.
* The signal will be noticed when one of them returns
* to userspace.
*/
signotify(p);
/*
* The signal will be noticed very soon.
*/
goto out;
/*NOTREACHED*/
} else {
/*
* Find out if any of the sleeps are interruptable,
* and if all the live LWPs remaining are suspended.
*/
allsusp = 1;
LIST_FOREACH(l, &p->p_lwps, l_sibling) {
if (l->l_stat == LSSLEEP &&
l->l_flag & L_SINTR)
break;
if (l->l_stat == LSSUSPENDED)
suspended = l;
else if ((l->l_stat != LSZOMB) &&
(l->l_stat != LSDEAD))
allsusp = 0;
}
}
found:
switch (p->p_stat) {
case SACTIVE:
if (l != NULL && (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 done;
}
/*
* 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.
*/
child_psignal(p, 0);
}
proc_stop(p, 1); /* XXXSMP: recurse? */
goto done;
}
if (l == NULL) {
/*
* Special case: SIGKILL of a process
* which is entirely composed of
* suspended LWPs should succeed. We
* make this happen by unsuspending one of
* them.
*/
if (allsusp && (signum == SIGKILL)) {
if (p->p_flag & P_SA) {
/*
* get a suspended lwp from
* the cache to send KILL
* signal
* XXXcl add signal checks at resume points
*/
suspended = sa_getcachelwp
(SLIST_FIRST(&p->p_sa->sa_vps));
}
lwp_continue(suspended);
}
goto done;
}
/*
* All other (caught or default) signals
* cause the process to run.
*/
goto runfast;
/*NOTREACHED*/
case SSTOP:
/* Process is stopped */
/*
* If traced process is already stopped,
* then no further action is necessary.
*/
if (p->p_flag & P_TRACED)
goto done;
/*
* Kill signal always sets processes running,
* if possible.
*/
if (signum == SIGKILL) {
l = proc_unstop(p);
if (l)
goto runfast;
goto done;
}
if (prop & SA_CONT) {
/*
* If SIGCONT is default (or ignored),
* we continue the process but don't
* leave the signal in ps_siglist, as
* it has no further action. If
* SIGCONT is held, we continue the
* process and leave the signal in
* 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);
l = proc_unstop(p);
if (l && (action == SIG_CATCH))
goto runfast;
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 done;
}
/*
* If a lwp is sleeping interruptibly, then
* wake it up; it will run until the kernel
* boundary, where it will stop in issignal(),
* since p->p_stat is still SSTOP. When the
* process is continued, it will be made
* runnable and can look at the signal.
*/
if (l)
goto run;
goto out;
case SIDL:
/* Process is being created by fork */
/* XXX: We are not ready to receive signals yet */
goto done;
default:
/* Else what? */
panic("psignal: Invalid process state %d.", p->p_stat);
}
/*NOTREACHED*/
runfast:
if (action == SIG_CATCH) {
ksiginfo_put(p, ksi);
action = SIG_HOLD;
}
/*
* Raise priority to at least PUSER.
*/
if (l->l_priority > PUSER)
l->l_priority = PUSER;
run:
if (action == SIG_CATCH) {
ksiginfo_put(p, ksi);
action = SIG_HOLD;
}
setrunnable(l); /* XXXSMP: recurse? */
out:
if (action == SIG_CATCH)
ksiginfo_put(p, ksi);
done:
/* XXXSMP: works, but icky */
if (dolock)
SCHED_UNLOCK(s);
}
void
kpsendsig(struct lwp *l, const ksiginfo_t *ksi, const sigset_t *mask)
{
struct proc *p = l->l_proc;
struct lwp *le, *li;
siginfo_t *si;
int f;
if (p->p_flag & P_SA) {
/* XXXUPSXXX What if not on sa_vp ? */
f = l->l_flag & L_SA;
l->l_flag &= ~L_SA;
si = pool_get(&siginfo_pool, PR_WAITOK);
si->_info = ksi->ksi_info;
le = li = NULL;
if (KSI_TRAP_P(ksi))
le = l;
else
li = l;
if (sa_upcall(l, SA_UPCALL_SIGNAL | SA_UPCALL_DEFER, le, li,
sizeof(*si), si) != 0) {
pool_put(&siginfo_pool, si);
if (KSI_TRAP_P(ksi))
/* XXX What do we do here?? */;
}
l->l_flag |= f;
return;
}
(*p->p_emul->e_sendsig)(ksi, mask);
}
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(curlwp))
* postsig(signum);
*/
int
issignal(struct lwp *l)
{
struct proc *p = l->l_proc;
int s = 0, signum, prop;
int dolock = (l->l_flag & L_SINTR) == 0, locked = !dolock;
sigset_t ss;
/* Bail out if we do not own the virtual processor */
if (l->l_flag & L_SA && l->l_savp->savp_lwp != l)
return 0;
if (p->p_stat == SSTOP) {
/*
* The process is stopped/stopping. Stop ourselves now that
* we're on the kernel/userspace boundary.
*/
if (dolock)
SCHED_LOCK(s);
l->l_stat = LSSTOP;
p->p_nrlwps--;
if (p->p_flag & P_TRACED)
goto sigtraceswitch;
else
goto sigswitch;
}
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;
if (locked && dolock)
SCHED_LOCK(s);
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;
/* Emulation-specific handling of signal trace */
if ((p->p_emul->e_tracesig != NULL) &&
((*p->p_emul->e_tracesig)(p, signum) != 0))
goto childresumed;
if ((p->p_flag & P_FSTRACE) == 0)
child_psignal(p, dolock);
if (dolock)
SCHED_LOCK(s);
proc_stop(p, 1);
sigtraceswitch:
mi_switch(l, NULL);
SCHED_ASSERT_UNLOCKED();
if (dolock)
splx(s);
else
dolock = 1;
childresumed:
/*
* 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_xstat = 0;
/*
* `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)
child_psignal(p, dolock);
if (dolock)
SCHED_LOCK(s);
proc_stop(p, 1);
sigswitch:
mi_switch(l, NULL);
SCHED_ASSERT_UNLOCKED();
if (dolock)
splx(s);
else
dolock = 1;
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.
*/
#ifdef DEBUG_ISSIGNAL
if ((prop & SA_CONT) == 0 &&
(p->p_flag & P_TRACED) == 0)
printf("issignal\n");
#endif
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);
if (locked && dolock)
SCHED_LOCK(s);
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.
*/
void
proc_stop(struct proc *p, int wakeup)
{
struct lwp *l;
struct proc *parent;
struct sadata_vp *vp;
SCHED_ASSERT_LOCKED();
/* XXX lock process LWP state */
p->p_flag &= ~P_WAITED;
p->p_stat = SSTOP;
parent = p->p_pptr;
parent->p_nstopchild++;
if (p->p_flag & P_SA) {
/*
* Only (try to) put the LWP on the VP in stopped
* state.
* All other LWPs will suspend in sa_setwoken()
* because the VP-LWP in stopped state cannot be
* repossessed.
*/
SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) {
l = vp->savp_lwp;
if (l->l_stat == LSONPROC && l->l_cpu == curcpu()) {
l->l_stat = LSSTOP;
p->p_nrlwps--;
} else if (l->l_stat == LSRUN) {
/* Remove LWP from the run queue */
remrunqueue(l);
l->l_stat = LSSTOP;
p->p_nrlwps--;
} else if (l->l_stat == LSSLEEP &&
l->l_flag & L_SA_IDLE) {
l->l_flag &= ~L_SA_IDLE;
l->l_stat = LSSTOP;
}
}
goto out;
}
/*
* Put as many LWP's as possible in stopped state.
* Sleeping ones will notice the stopped state as they try to
* return to userspace.
*/
LIST_FOREACH(l, &p->p_lwps, l_sibling) {
if (l->l_stat == LSONPROC) {
/* XXX SMP this assumes that a LWP that is LSONPROC
* is curlwp and hence is about to be mi_switched
* away; the only callers of proc_stop() are:
* - psignal
* - issignal()
* For the former, proc_stop() is only called when
* no processes are running, so we don't worry.
* For the latter, proc_stop() is called right
* before mi_switch().
*/
l->l_stat = LSSTOP;
p->p_nrlwps--;
} else if (l->l_stat == LSRUN) {
/* Remove LWP from the run queue */
remrunqueue(l);
l->l_stat = LSSTOP;
p->p_nrlwps--;
} else if ((l->l_stat == LSSLEEP) ||
(l->l_stat == LSSUSPENDED) ||
(l->l_stat == LSZOMB) ||
(l->l_stat == LSDEAD)) {
/*
* Don't do anything; let sleeping LWPs
* discover the stopped state of the process
* on their way out of the kernel; otherwise,
* things like NFS threads that sleep with
* locks will block the rest of the system
* from getting any work done.
*
* Suspended/dead/zombie LWPs aren't going
* anywhere, so we don't need to touch them.
*/
}
#ifdef DIAGNOSTIC
else {
panic("proc_stop: process %d lwp %d "
"in unstoppable state %d.\n",
p->p_pid, l->l_lid, l->l_stat);
}
#endif
}
out:
/* XXX unlock process LWP state */
if (wakeup)
sched_wakeup((caddr_t)p->p_pptr);
}
/*
* Given a process in state SSTOP, set the state back to SACTIVE and
* move LSSTOP'd LWPs to LSSLEEP or make them runnable.
*
* If no LWPs ended up runnable (and therefore able to take a signal),
* return a LWP that is sleeping interruptably. The caller can wake
* that LWP up to take a signal.
*/
struct lwp *
proc_unstop(struct proc *p)
{
struct lwp *l, *lr = NULL;
struct sadata_vp *vp;
int cantake = 0;
SCHED_ASSERT_LOCKED();
/*
* Our caller wants to be informed if there are only sleeping
* and interruptable LWPs left after we have run so that it
* can invoke setrunnable() if required - return one of the
* interruptable LWPs if this is the case.
*/
if (!(p->p_flag & P_WAITED))
p->p_pptr->p_nstopchild--;
p->p_stat = SACTIVE;
LIST_FOREACH(l, &p->p_lwps, l_sibling) {
if (l->l_stat == LSRUN) {
lr = NULL;
cantake = 1;
}
if (l->l_stat != LSSTOP)
continue;
if (l->l_wchan != NULL) {
l->l_stat = LSSLEEP;
if ((cantake == 0) && (l->l_flag & L_SINTR)) {
lr = l;
cantake = 1;
}
} else {
setrunnable(l);
lr = NULL;
cantake = 1;
}
}
if (p->p_flag & P_SA) {
/* Only consider returning the LWP on the VP. */
SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) {
lr = vp->savp_lwp;
if (lr->l_stat == LSSLEEP) {
if (lr->l_flag & L_SA_YIELD) {
setrunnable(lr);
break;
} else if (lr->l_flag & L_SINTR)
return lr;
}
}
return NULL;
}
return lr;
}
/*
* Take the action for the specified signal
* from the current set of pending signals.
*/
void
postsig(int signum)
{
struct lwp *l;
struct proc *p;
struct sigacts *ps;
sig_t action;
sigset_t *returnmask;
l = curlwp;
p = l->l_proc;
ps = p->p_sigacts;
#ifdef DIAGNOSTIC
if (signum == 0)
panic("postsig");
#endif
KERNEL_PROC_LOCK(l);
#ifdef MULTIPROCESSOR
/*
* On MP, issignal() can return the same signal to multiple
* LWPs. The LWPs will block above waiting for the kernel
* lock and the first LWP which gets through will then remove
* the signal from ps_siglist. All other LWPs exit here.
*/
if (!sigismember(&p->p_sigctx.ps_siglist, signum)) {
KERNEL_PROC_UNLOCK(l);
return;
}
#endif
sigdelset(&p->p_sigctx.ps_siglist, signum);
action = SIGACTION_PS(ps, signum).sa_handler;
if (action == SIG_DFL) {
#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,
NULL);
#endif
/*
* Default action, where the default is to kill
* the process. (Other cases were ignored above.)
*/
sigexit(l, signum);
/* NOTREACHED */
} else {
ksiginfo_t *ksi;
/*
* 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
* occurrences 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++;
ksi = ksiginfo_get(p, signum);
#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,
ksi);
#endif
if (ksi == NULL) {
ksiginfo_t ksi1;
/*
* we did not save any siginfo for this, either
* because the signal was not caught, or because the
* user did not request SA_SIGINFO
*/
KSI_INIT_EMPTY(&ksi1);
ksi1.ksi_signo = signum;
kpsendsig(l, &ksi1, returnmask);
} else {
kpsendsig(l, ksi, returnmask);
pool_put(&ksiginfo_pool, ksi);
}
p->p_sigctx.ps_lwp = 0;
p->p_sigctx.ps_code = 0;
p->p_sigctx.ps_signo = 0;
(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(l);
}
/*
* Kill the current process for stated reason.
*/
void
killproc(struct proc *p, const 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";
/* Wrapper function for use in p_userret */
static void
lwp_coredump_hook(struct lwp *l, void *arg)
{
int s;
/*
* Suspend ourselves, so that the kernel stack and therefore
* the userland registers saved in the trapframe are around
* for coredump() to write them out.
*/
KERNEL_PROC_LOCK(l);
l->l_flag &= ~L_DETACHED;
SCHED_LOCK(s);
l->l_stat = LSSUSPENDED;
l->l_proc->p_nrlwps--;
/* XXX NJWLWP check if this makes sense here: */
l->l_proc->p_stats->p_ru.ru_nvcsw++;
mi_switch(l, NULL);
SCHED_ASSERT_UNLOCKED();
splx(s);
lwp_exit(l);
}
void
sigexit(struct lwp *l, int signum)
{
struct proc *p;
#if 0
struct lwp *l2;
#endif
int error, exitsig;
p = l->l_proc;
/*
* Don't permit coredump() or exit1() multiple times
* in the same process.
*/
if (p->p_flag & P_WEXIT) {
KERNEL_PROC_UNLOCK(l);
(*p->p_userret)(l, p->p_userret_arg);
}
p->p_flag |= P_WEXIT;
/* We don't want to switch away from exiting. */
/* XXX multiprocessor: stop LWPs on other processors. */
#if 0
if (p->p_flag & P_SA) {
LIST_FOREACH(l2, &p->p_lwps, l_sibling)
l2->l_flag &= ~L_SA;
p->p_flag &= ~P_SA;
}
#endif
/* Make other LWPs stick around long enough to be dumped */
p->p_userret = lwp_coredump_hook;
p->p_userret_arg = NULL;
exitsig = signum;
p->p_acflag |= AXSIG;
if (sigprop[signum] & SA_CORE) {
p->p_sigctx.ps_signo = signum;
if ((error = coredump(l, NULL)) == 0)
exitsig |= WCOREFLAG;
if (kern_logsigexit) {
/* XXX What if we ever have really large UIDs? */
int uid = p->p_cred && p->p_ucred ?
(int) 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(l, 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 lwp *l, const char *pattern)
{
struct vnode *vp;
struct proc *p;
struct vmspace *vm;
struct ucred *cred;
struct nameidata nd;
struct vattr vattr;
struct mount *mp;
int error, error1;
char name[MAXPATHLEN];
p = l->l_proc;
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? */
restart:
/*
* 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);
if (pattern == NULL)
pattern = p->p_limit->pl_corename;
if ((error = build_corename(p, name, pattern, sizeof(name))) != 0)
return error;
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p);
error = vn_open(&nd, O_CREAT | O_NOFOLLOW | FWRITE, S_IRUSR | S_IWUSR);
if (error)
return (error);
vp = nd.ni_vp;
if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
VOP_UNLOCK(vp, 0);
if ((error = vn_close(vp, FWRITE, cred, p)) != 0)
return (error);
if ((error = vn_start_write(NULL, &mp,
V_WAIT | V_SLEEPONLY | V_PCATCH)) != 0)
return (error);
goto restart;
}
/* 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;
/* Now dump the actual core file. */
error = (*p->p_execsw->es_coredump)(l, vp, cred);
out:
VOP_UNLOCK(vp, 0);
vn_finished_write(mp, 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 lwp *l, void *v, register_t *retval)
{
struct proc *p;
p = l->l_proc;
psignal(p, SIGSYS);
return (ENOSYS);
}
static int
build_corename(struct proc *p, char *dst, const char *src, size_t len)
{
const char *s;
char *d, *end;
int i;
for (s = src, d = dst, end = d + len; *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",
(int)sizeof p->p_pgrp->pg_session->s_login,
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;
}
void
getucontext(struct lwp *l, ucontext_t *ucp)
{
struct proc *p;
p = l->l_proc;
ucp->uc_flags = 0;
ucp->uc_link = l->l_ctxlink;
(void)sigprocmask1(p, 0, NULL, &ucp->uc_sigmask);
ucp->uc_flags |= _UC_SIGMASK;
/*
* The (unsupplied) definition of the `current execution stack'
* in the System V Interface Definition appears to allow returning
* the main context stack.
*/
if ((p->p_sigctx.ps_sigstk.ss_flags & SS_ONSTACK) == 0) {
ucp->uc_stack.ss_sp = (void *)USRSTACK;
ucp->uc_stack.ss_size = ctob(p->p_vmspace->vm_ssize);
ucp->uc_stack.ss_flags = 0; /* XXX, def. is Very Fishy */
} else {
/* Simply copy alternate signal execution stack. */
ucp->uc_stack = p->p_sigctx.ps_sigstk;
}
ucp->uc_flags |= _UC_STACK;
cpu_getmcontext(l, &ucp->uc_mcontext, &ucp->uc_flags);
}
/* ARGSUSED */
int
sys_getcontext(struct lwp *l, void *v, register_t *retval)
{
struct sys_getcontext_args /* {
syscallarg(struct __ucontext *) ucp;
} */ *uap = v;
ucontext_t uc;
getucontext(l, &uc);
return (copyout(&uc, SCARG(uap, ucp), sizeof (*SCARG(uap, ucp))));
}
int
setucontext(struct lwp *l, const ucontext_t *ucp)
{
struct proc *p;
int error;
p = l->l_proc;
if ((error = cpu_setmcontext(l, &ucp->uc_mcontext, ucp->uc_flags)) != 0)
return (error);
l->l_ctxlink = ucp->uc_link;
if ((ucp->uc_flags & _UC_SIGMASK) != 0)
sigprocmask1(p, SIG_SETMASK, &ucp->uc_sigmask, NULL);
/*
* If there was stack information, update whether or not we are
* still running on an alternate signal stack.
*/
if ((ucp->uc_flags & _UC_STACK) != 0) {
if (ucp->uc_stack.ss_flags & SS_ONSTACK)
p->p_sigctx.ps_sigstk.ss_flags |= SS_ONSTACK;
else
p->p_sigctx.ps_sigstk.ss_flags &= ~SS_ONSTACK;
}
return 0;
}
/* ARGSUSED */
int
sys_setcontext(struct lwp *l, void *v, register_t *retval)
{
struct sys_setcontext_args /* {
syscallarg(const ucontext_t *) ucp;
} */ *uap = v;
ucontext_t uc;
int error;
if (SCARG(uap, ucp) == NULL) /* i.e. end of uc_link chain */
exit1(l, W_EXITCODE(0, 0));
else if ((error = copyin(SCARG(uap, ucp), &uc, sizeof (uc))) != 0 ||
(error = setucontext(l, &uc)) != 0)
return (error);
return (EJUSTRETURN);
}
/*
* sigtimedwait(2) system call, used also for implementation
* of sigwaitinfo() and sigwait().
*
* This only handles single LWP in signal wait. libpthread provides
* it's own sigtimedwait() wrapper to DTRT WRT individual threads.
*/
int
sys___sigtimedwait(struct lwp *l, void *v, register_t *retval)
{
struct sys___sigtimedwait_args /* {
syscallarg(const sigset_t *) set;
syscallarg(siginfo_t *) info;
syscallarg(struct timespec *) timeout;
} */ *uap = v;
sigset_t *waitset, twaitset;
struct proc *p = l->l_proc;
int error, signum, s;
int timo = 0;
struct timeval tvstart;
struct timespec ts;
ksiginfo_t *ksi;
MALLOC(waitset, sigset_t *, sizeof(sigset_t), M_TEMP, M_WAITOK);
if ((error = copyin(SCARG(uap, set), waitset, sizeof(sigset_t)))) {
FREE(waitset, M_TEMP);
return (error);
}
/*
* Silently ignore SA_CANTMASK signals. psignal1() would
* ignore SA_CANTMASK signals in waitset, we do this
* only for the below siglist check.
*/
sigminusset(&sigcantmask, waitset);
/*
* First scan siglist and check if there is signal from
* our waitset already pending.
*/
twaitset = *waitset;
__sigandset(&p->p_sigctx.ps_siglist, &twaitset);
if ((signum = firstsig(&twaitset))) {
/* found pending signal */
sigdelset(&p->p_sigctx.ps_siglist, signum);
ksi = ksiginfo_get(p, signum);
if (!ksi) {
/* No queued siginfo, manufacture one */
ksi = pool_get(&ksiginfo_pool, PR_WAITOK);
KSI_INIT(ksi);
ksi->ksi_info._signo = signum;
ksi->ksi_info._code = SI_USER;
}
goto sig;
}
/*
* Calculate timeout, if it was specified.
*/
if (SCARG(uap, timeout)) {
uint64_t ms;
if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))))
return (error);
ms = (ts.tv_sec * 1000) + (ts.tv_nsec / 1000000);
timo = mstohz(ms);
if (timo == 0 && ts.tv_sec == 0 && ts.tv_nsec > 0)
timo = 1;
if (timo <= 0)
return (EAGAIN);
/*
* Remember current mono_time, it would be used in
* ECANCELED/ERESTART case.
*/
s = splclock();
tvstart = mono_time;
splx(s);
}
/*
* Setup ps_sigwait list. Pass pointer to malloced memory
* here; it's not possible to pass pointer to a structure
* on current process's stack, the current process might
* be swapped out at the time the signal would get delivered.
*/
ksi = pool_get(&ksiginfo_pool, PR_WAITOK);
p->p_sigctx.ps_sigwaited = ksi;
p->p_sigctx.ps_sigwait = waitset;
/*
* Wait for signal to arrive. We can either be woken up or
* time out.
*/
error = tsleep(&p->p_sigctx.ps_sigwait, PPAUSE|PCATCH, "sigwait", timo);
/*
* Need to find out if we woke as a result of lwp_wakeup()
* or a signal outside our wait set.
*/
if (error == EINTR && p->p_sigctx.ps_sigwaited
&& !firstsig(&p->p_sigctx.ps_siglist)) {
/* wakeup via _lwp_wakeup() */
error = ECANCELED;
} else if (!error && p->p_sigctx.ps_sigwaited) {
/* spurious wakeup - arrange for syscall restart */
error = ERESTART;
goto fail;
}
/*
* On error, clear sigwait indication. psignal1() clears it
* in !error case.
*/
if (error) {
p->p_sigctx.ps_sigwaited = NULL;
/*
* If the sleep was interrupted (either by signal or wakeup),
* update the timeout and copyout new value back.
* It would be used when the syscall would be restarted
* or called again.
*/
if (timo && (error == ERESTART || error == ECANCELED)) {
struct timeval tvnow, tvtimo;
int err;
s = splclock();
tvnow = mono_time;
splx(s);
TIMESPEC_TO_TIMEVAL(&tvtimo, &ts);
/* compute how much time has passed since start */
timersub(&tvnow, &tvstart, &tvnow);
/* substract passed time from timeout */
timersub(&tvtimo, &tvnow, &tvtimo);
if (tvtimo.tv_sec < 0) {
error = EAGAIN;
goto fail;
}
TIMEVAL_TO_TIMESPEC(&tvtimo, &ts);
/* copy updated timeout to userland */
if ((err = copyout(&ts, SCARG(uap, timeout), sizeof(ts)))) {
error = err;
goto fail;
}
}
goto fail;
}
/*
* If a signal from the wait set arrived, copy it to userland.
* Copy only the used part of siginfo, the padding part is
* left unchanged (userland is not supposed to touch it anyway).
*/
sig:
error = copyout(&ksi->ksi_info, SCARG(uap, info), sizeof(ksi->ksi_info));
fail:
FREE(waitset, M_TEMP);
pool_put(&ksiginfo_pool, ksi);
p->p_sigctx.ps_sigwait = NULL;
return (error);
}
/*
* 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, sig) ||
sigismember(&p->p_sigctx.ps_sigmask, sig));
}
static int
filt_sigattach(struct knote *kn)
{
struct proc *p = curproc;
kn->kn_ptr.p_proc = p;
kn->kn_flags |= EV_CLEAR; /* automatically set */
SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
return (0);
}
static void
filt_sigdetach(struct knote *kn)
{
struct proc *p = kn->kn_ptr.p_proc;
SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
}
/*
* signal knotes are shared with proc knotes, so we apply a mask to
* the hint in order to differentiate them from process hints. This
* could be avoided by using a signal-specific knote list, but probably
* isn't worth the trouble.
*/
static int
filt_signal(struct knote *kn, long hint)
{
if (hint & NOTE_SIGNAL) {
hint &= ~NOTE_SIGNAL;
if (kn->kn_id == hint)
kn->kn_data++;
}
return (kn->kn_data != 0);
}
const struct filterops sig_filtops = {
0, filt_sigattach, filt_sigdetach, filt_signal
};
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