/
kern_sig.c
2307 lines (2044 loc) · 52.8 KB
/
kern_sig.c
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/* $OpenBSD: kern_sig.c,v 1.245 2020/02/01 15:52:34 anton Exp $ */
/* $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $ */
/*
* Copyright (c) 1997 Theo de Raadt. All rights reserved.
* 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 8.7 (Berkeley) 4/18/94
*/
#define SIGPROP /* include signal properties table */
#include <sys/param.h>
#include <sys/signalvar.h>
#include <sys/resourcevar.h>
#include <sys/queue.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/event.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/acct.h>
#include <sys/fcntl.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/wait.h>
#include <sys/ktrace.h>
#include <sys/stat.h>
#include <sys/core.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/ptrace.h>
#include <sys/sched.h>
#include <sys/user.h>
#include <sys/syslog.h>
#include <sys/ttycom.h>
#include <sys/pledge.h>
#include <sys/witness.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <uvm/uvm_extern.h>
#include <machine/tcb.h>
int filt_sigattach(struct knote *kn);
void filt_sigdetach(struct knote *kn);
int filt_signal(struct knote *kn, long hint);
const struct filterops sig_filtops = {
.f_isfd = 0,
.f_attach = filt_sigattach,
.f_detach = filt_sigdetach,
.f_event = filt_signal,
};
void proc_stop(struct proc *p, int);
void proc_stop_sweep(void *);
struct timeout proc_stop_to;
void postsig(struct proc *, int);
int cansignal(struct proc *, struct process *, int);
struct pool sigacts_pool; /* memory pool for sigacts structures */
void sigio_del(struct sigiolst *);
void sigio_unlink(struct sigio_ref *, struct sigiolst *);
struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH);
/*
* Can thread p, send the signal signum to process qr?
*/
int
cansignal(struct proc *p, struct process *qr, int signum)
{
struct process *pr = p->p_p;
struct ucred *uc = p->p_ucred;
struct ucred *quc = qr->ps_ucred;
if (uc->cr_uid == 0)
return (1); /* root can always signal */
if (pr == qr)
return (1); /* process can always signal itself */
/* optimization: if the same creds then the tests below will pass */
if (uc == quc)
return (1);
if (signum == SIGCONT && qr->ps_session == pr->ps_session)
return (1); /* SIGCONT in session */
/*
* Using kill(), only certain signals can be sent to setugid
* child processes
*/
if (qr->ps_flags & PS_SUGID) {
switch (signum) {
case 0:
case SIGKILL:
case SIGINT:
case SIGTERM:
case SIGALRM:
case SIGSTOP:
case SIGTTIN:
case SIGTTOU:
case SIGTSTP:
case SIGHUP:
case SIGUSR1:
case SIGUSR2:
if (uc->cr_ruid == quc->cr_ruid ||
uc->cr_uid == quc->cr_ruid)
return (1);
}
return (0);
}
if (uc->cr_ruid == quc->cr_ruid ||
uc->cr_ruid == quc->cr_svuid ||
uc->cr_uid == quc->cr_ruid ||
uc->cr_uid == quc->cr_svuid)
return (1);
return (0);
}
/*
* Initialize signal-related data structures.
*/
void
signal_init(void)
{
timeout_set(&proc_stop_to, proc_stop_sweep, NULL);
pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE,
PR_WAITOK, "sigapl", NULL);
}
/*
* Create an initial sigacts structure, using the same signal state
* as p.
*/
struct sigacts *
sigactsinit(struct process *pr)
{
struct sigacts *ps;
ps = pool_get(&sigacts_pool, PR_WAITOK);
memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts));
ps->ps_refcnt = 1;
return (ps);
}
/*
* Share a sigacts structure.
*/
struct sigacts *
sigactsshare(struct process *pr)
{
struct sigacts *ps = pr->ps_sigacts;
ps->ps_refcnt++;
return ps;
}
/*
* Initialize a new sigaltstack structure.
*/
void
sigstkinit(struct sigaltstack *ss)
{
ss->ss_flags = SS_DISABLE;
ss->ss_size = 0;
ss->ss_sp = 0;
}
/*
* Make this process not share its sigacts, maintaining all
* signal state.
*/
void
sigactsunshare(struct process *pr)
{
struct sigacts *newps;
if (pr->ps_sigacts->ps_refcnt == 1)
return;
newps = sigactsinit(pr);
sigactsfree(pr);
pr->ps_sigacts = newps;
}
/*
* Release a sigacts structure.
*/
void
sigactsfree(struct process *pr)
{
struct sigacts *ps = pr->ps_sigacts;
if (--ps->ps_refcnt > 0)
return;
pr->ps_sigacts = NULL;
pool_put(&sigacts_pool, ps);
}
int
sys_sigaction(struct proc *p, void *v, register_t *retval)
{
struct sys_sigaction_args /* {
syscallarg(int) signum;
syscallarg(const struct sigaction *) nsa;
syscallarg(struct sigaction *) osa;
} */ *uap = v;
struct sigaction vec;
#ifdef KTRACE
struct sigaction ovec;
#endif
struct sigaction *sa;
const struct sigaction *nsa;
struct sigaction *osa;
struct sigacts *ps = p->p_p->ps_sigacts;
int signum;
int bit, error;
signum = SCARG(uap, signum);
nsa = SCARG(uap, nsa);
osa = SCARG(uap, osa);
if (signum <= 0 || signum >= NSIG ||
(nsa && (signum == SIGKILL || signum == SIGSTOP)))
return (EINVAL);
sa = &vec;
if (osa) {
sa->sa_handler = ps->ps_sigact[signum];
sa->sa_mask = ps->ps_catchmask[signum];
bit = sigmask(signum);
sa->sa_flags = 0;
if ((ps->ps_sigonstack & bit) != 0)
sa->sa_flags |= SA_ONSTACK;
if ((ps->ps_sigintr & bit) == 0)
sa->sa_flags |= SA_RESTART;
if ((ps->ps_sigreset & bit) != 0)
sa->sa_flags |= SA_RESETHAND;
if ((ps->ps_siginfo & bit) != 0)
sa->sa_flags |= SA_SIGINFO;
if (signum == SIGCHLD) {
if ((ps->ps_flags & SAS_NOCLDSTOP) != 0)
sa->sa_flags |= SA_NOCLDSTOP;
if ((ps->ps_flags & SAS_NOCLDWAIT) != 0)
sa->sa_flags |= SA_NOCLDWAIT;
}
if ((sa->sa_mask & bit) == 0)
sa->sa_flags |= SA_NODEFER;
sa->sa_mask &= ~bit;
error = copyout(sa, osa, sizeof (vec));
if (error)
return (error);
#ifdef KTRACE
if (KTRPOINT(p, KTR_STRUCT))
ovec = vec;
#endif
}
if (nsa) {
error = copyin(nsa, sa, sizeof (vec));
if (error)
return (error);
#ifdef KTRACE
if (KTRPOINT(p, KTR_STRUCT))
ktrsigaction(p, sa);
#endif
setsigvec(p, signum, sa);
}
#ifdef KTRACE
if (osa && KTRPOINT(p, KTR_STRUCT))
ktrsigaction(p, &ovec);
#endif
return (0);
}
void
setsigvec(struct proc *p, int signum, struct sigaction *sa)
{
struct sigacts *ps = p->p_p->ps_sigacts;
int bit;
int s;
bit = sigmask(signum);
/*
* Change setting atomically.
*/
s = splhigh();
ps->ps_sigact[signum] = sa->sa_handler;
if ((sa->sa_flags & SA_NODEFER) == 0)
sa->sa_mask |= sigmask(signum);
ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask;
if (signum == SIGCHLD) {
if (sa->sa_flags & SA_NOCLDSTOP)
atomic_setbits_int(&ps->ps_flags, SAS_NOCLDSTOP);
else
atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDSTOP);
/*
* If the SA_NOCLDWAIT flag is set or the handler
* is SIG_IGN we reparent the dying child to PID 1
* (init) which will reap the zombie. Because we use
* init to do our dirty work we never set SAS_NOCLDWAIT
* for PID 1.
* XXX exit1 rework means this is unnecessary?
*/
if (initprocess->ps_sigacts != ps &&
((sa->sa_flags & SA_NOCLDWAIT) ||
sa->sa_handler == SIG_IGN))
atomic_setbits_int(&ps->ps_flags, SAS_NOCLDWAIT);
else
atomic_clearbits_int(&ps->ps_flags, SAS_NOCLDWAIT);
}
if ((sa->sa_flags & SA_RESETHAND) != 0)
ps->ps_sigreset |= bit;
else
ps->ps_sigreset &= ~bit;
if ((sa->sa_flags & SA_SIGINFO) != 0)
ps->ps_siginfo |= bit;
else
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) != 0)
ps->ps_sigonstack |= bit;
else
ps->ps_sigonstack &= ~bit;
/*
* Set bit in 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 ps_sigignore,
* as we have to restart the process.
*/
if (sa->sa_handler == SIG_IGN ||
(sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) {
atomic_clearbits_int(&p->p_siglist, bit);
atomic_clearbits_int(&p->p_p->ps_siglist, bit);
if (signum != SIGCONT)
ps->ps_sigignore |= bit; /* easier in psignal */
ps->ps_sigcatch &= ~bit;
} else {
ps->ps_sigignore &= ~bit;
if (sa->sa_handler == SIG_DFL)
ps->ps_sigcatch &= ~bit;
else
ps->ps_sigcatch |= bit;
}
splx(s);
}
/*
* Initialize signal state for process 0;
* set to ignore signals that are ignored by default.
*/
void
siginit(struct process *pr)
{
struct sigacts *ps = pr->ps_sigacts;
int i;
for (i = 0; i < NSIG; i++)
if (sigprop[i] & SA_IGNORE && i != SIGCONT)
ps->ps_sigignore |= sigmask(i);
ps->ps_flags = SAS_NOCLDWAIT | SAS_NOCLDSTOP;
}
/*
* Reset signals for an exec by the specified thread.
*/
void
execsigs(struct proc *p)
{
struct sigacts *ps;
int nc, mask;
sigactsunshare(p->p_p);
ps = p->p_p->ps_sigacts;
/*
* Reset caught signals. Held signals remain held
* through p_sigmask (unless they were caught,
* and are now ignored by default).
*/
while (ps->ps_sigcatch) {
nc = ffs((long)ps->ps_sigcatch);
mask = sigmask(nc);
ps->ps_sigcatch &= ~mask;
if (sigprop[nc] & SA_IGNORE) {
if (nc != SIGCONT)
ps->ps_sigignore |= mask;
atomic_clearbits_int(&p->p_siglist, mask);
atomic_clearbits_int(&p->p_p->ps_siglist, mask);
}
ps->ps_sigact[nc] = SIG_DFL;
}
/*
* Reset stack state to the user stack.
* Clear set of signals caught on the signal stack.
*/
sigstkinit(&p->p_sigstk);
ps->ps_flags &= ~SAS_NOCLDWAIT;
if (ps->ps_sigact[SIGCHLD] == SIG_IGN)
ps->ps_sigact[SIGCHLD] = SIG_DFL;
}
/*
* 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_sigprocmask(struct proc *p, void *v, register_t *retval)
{
struct sys_sigprocmask_args /* {
syscallarg(int) how;
syscallarg(sigset_t) mask;
} */ *uap = v;
int error = 0;
sigset_t mask;
*retval = p->p_sigmask;
mask = SCARG(uap, mask) &~ sigcantmask;
switch (SCARG(uap, how)) {
case SIG_BLOCK:
atomic_setbits_int(&p->p_sigmask, mask);
break;
case SIG_UNBLOCK:
atomic_clearbits_int(&p->p_sigmask, mask);
break;
case SIG_SETMASK:
p->p_sigmask = mask;
break;
default:
error = EINVAL;
break;
}
return (error);
}
int
sys_sigpending(struct proc *p, void *v, register_t *retval)
{
*retval = p->p_siglist | p->p_p->ps_siglist;
return (0);
}
/*
* Temporarily replace calling proc's signal mask for the duration of a
* system call. Original signal mask will be restored by userret().
*/
void
dosigsuspend(struct proc *p, sigset_t newmask)
{
KASSERT(p == curproc);
p->p_oldmask = p->p_sigmask;
atomic_setbits_int(&p->p_flag, P_SIGSUSPEND);
p->p_sigmask = newmask;
}
/*
* 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.
*/
int
sys_sigsuspend(struct proc *p, void *v, register_t *retval)
{
struct sys_sigsuspend_args /* {
syscallarg(int) mask;
} */ *uap = v;
struct process *pr = p->p_p;
struct sigacts *ps = pr->ps_sigacts;
dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask);
while (tsleep_nsec(ps, PPAUSE|PCATCH, "pause", INFSLP) == 0)
/* void */;
/* always return EINTR rather than ERESTART... */
return (EINTR);
}
int
sigonstack(size_t stack)
{
const struct sigaltstack *ss = &curproc->p_sigstk;
return (ss->ss_flags & SS_DISABLE ? 0 :
(stack - (size_t)ss->ss_sp < ss->ss_size));
}
int
sys_sigaltstack(struct proc *p, void *v, register_t *retval)
{
struct sys_sigaltstack_args /* {
syscallarg(const struct sigaltstack *) nss;
syscallarg(struct sigaltstack *) oss;
} */ *uap = v;
struct sigaltstack ss;
const struct sigaltstack *nss;
struct sigaltstack *oss;
int onstack = sigonstack(PROC_STACK(p));
int error;
nss = SCARG(uap, nss);
oss = SCARG(uap, oss);
if (oss != NULL) {
ss = p->p_sigstk;
if (onstack)
ss.ss_flags |= SS_ONSTACK;
if ((error = copyout(&ss, oss, sizeof(ss))))
return (error);
}
if (nss == NULL)
return (0);
error = copyin(nss, &ss, sizeof(ss));
if (error)
return (error);
if (onstack)
return (EPERM);
if (ss.ss_flags & ~SS_DISABLE)
return (EINVAL);
if (ss.ss_flags & SS_DISABLE) {
p->p_sigstk.ss_flags = ss.ss_flags;
return (0);
}
if (ss.ss_size < MINSIGSTKSZ)
return (ENOMEM);
error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size);
if (error)
return (error);
p->p_sigstk = ss;
return (0);
}
int
sys_kill(struct proc *cp, void *v, register_t *retval)
{
struct sys_kill_args /* {
syscallarg(int) pid;
syscallarg(int) signum;
} */ *uap = v;
struct process *pr;
int pid = SCARG(uap, pid);
int signum = SCARG(uap, signum);
int error;
int zombie = 0;
if ((error = pledge_kill(cp, pid)) != 0)
return (error);
if (((u_int)signum) >= NSIG)
return (EINVAL);
if (pid > 0) {
if ((pr = prfind(pid)) == NULL) {
if ((pr = zombiefind(pid)) == NULL)
return (ESRCH);
else
zombie = 1;
}
if (!cansignal(cp, pr, signum))
return (EPERM);
/* kill single process */
if (signum && !zombie)
prsignal(pr, signum);
return (0);
}
switch (pid) {
case -1: /* broadcast signal */
return (killpg1(cp, signum, 0, 1));
case 0: /* signal own process group */
return (killpg1(cp, signum, 0, 0));
default: /* negative explicit process group */
return (killpg1(cp, signum, -pid, 0));
}
}
int
sys_thrkill(struct proc *cp, void *v, register_t *retval)
{
struct sys_thrkill_args /* {
syscallarg(pid_t) tid;
syscallarg(int) signum;
syscallarg(void *) tcb;
} */ *uap = v;
struct proc *p;
int tid = SCARG(uap, tid);
int signum = SCARG(uap, signum);
void *tcb;
if (((u_int)signum) >= NSIG)
return (EINVAL);
if (tid > THREAD_PID_OFFSET) {
if ((p = tfind(tid - THREAD_PID_OFFSET)) == NULL)
return (ESRCH);
/* can only kill threads in the same process */
if (p->p_p != cp->p_p)
return (ESRCH);
} else if (tid == 0)
p = cp;
else
return (EINVAL);
/* optionally require the target thread to have the given tcb addr */
tcb = SCARG(uap, tcb);
if (tcb != NULL && tcb != TCB_GET(p))
return (ESRCH);
if (signum)
ptsignal(p, signum, STHREAD);
return (0);
}
/*
* Common code for kill process group/broadcast kill.
* cp is calling process.
*/
int
killpg1(struct proc *cp, int signum, int pgid, int all)
{
struct process *pr;
struct pgrp *pgrp;
int nfound = 0;
if (all) {
/*
* broadcast
*/
LIST_FOREACH(pr, &allprocess, ps_list) {
if (pr->ps_pid <= 1 ||
pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) ||
pr == cp->p_p || !cansignal(cp, pr, signum))
continue;
nfound++;
if (signum)
prsignal(pr, signum);
}
} else {
if (pgid == 0)
/*
* zero pgid means send to my process group.
*/
pgrp = cp->p_p->ps_pgrp;
else {
pgrp = pgfind(pgid);
if (pgrp == NULL)
return (ESRCH);
}
LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) {
if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM ||
!cansignal(cp, pr, signum))
continue;
nfound++;
if (signum)
prsignal(pr, signum);
}
}
return (nfound ? 0 : ESRCH);
}
#define CANDELIVER(uid, euid, pr) \
(euid == 0 || \
(uid) == (pr)->ps_ucred->cr_ruid || \
(uid) == (pr)->ps_ucred->cr_svuid || \
(uid) == (pr)->ps_ucred->cr_uid || \
(euid) == (pr)->ps_ucred->cr_ruid || \
(euid) == (pr)->ps_ucred->cr_svuid || \
(euid) == (pr)->ps_ucred->cr_uid)
#define CANSIGIO(cr, pr) \
CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr))
/*
* 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 process *pr;
if (pgrp)
LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist)
if (checkctty == 0 || pr->ps_flags & PS_CONTROLT)
prsignal(pr, signum);
}
/*
* Send a SIGIO or SIGURG signal to a process or process group using stored
* credentials rather than those of the current process.
*/
void
pgsigio(struct sigio_ref *sir, int sig, int checkctty)
{
struct process *pr;
struct sigio *sigio;
if (sir->sir_sigio == NULL)
return;
mtx_enter(&sigio_lock);
sigio = sir->sir_sigio;
if (sigio == NULL)
goto out;
if (sigio->sio_pgid > 0) {
if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc))
prsignal(sigio->sio_proc, sig);
} else if (sigio->sio_pgid < 0) {
LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) {
if (CANSIGIO(sigio->sio_ucred, pr) &&
(checkctty == 0 || (pr->ps_flags & PS_CONTROLT)))
prsignal(pr, sig);
}
}
out:
mtx_leave(&sigio_lock);
}
/*
* Recalculate the signal mask and reset the signal disposition after
* usermode frame for delivery is formed.
*/
void
postsig_done(struct proc *p, int signum, struct sigacts *ps)
{
int mask = sigmask(signum);
KERNEL_ASSERT_LOCKED();
p->p_ru.ru_nsignals++;
atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]);
if ((ps->ps_sigreset & mask) != 0) {
ps->ps_sigcatch &= ~mask;
if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
ps->ps_sigignore |= mask;
ps->ps_sigact[signum] = SIG_DFL;
}
}
/*
* Send a signal caused by a trap to the current thread
* If it will be caught immediately, deliver it with correct code.
* Otherwise, post it normally.
*/
void
trapsignal(struct proc *p, int signum, u_long trapno, int code,
union sigval sigval)
{
struct process *pr = p->p_p;
struct sigacts *ps = pr->ps_sigacts;
int mask;
switch (signum) {
case SIGILL:
case SIGBUS:
case SIGSEGV:
pr->ps_acflag |= ATRAP;
break;
}
mask = sigmask(signum);
if ((pr->ps_flags & PS_TRACED) == 0 &&
(ps->ps_sigcatch & mask) != 0 &&
(p->p_sigmask & mask) == 0) {
siginfo_t si;
initsiginfo(&si, signum, trapno, code, sigval);
#ifdef KTRACE
if (KTRPOINT(p, KTR_PSIG)) {
ktrpsig(p, signum, ps->ps_sigact[signum],
p->p_sigmask, code, &si);
}
#endif
sendsig(ps->ps_sigact[signum], signum, p->p_sigmask, &si);
postsig_done(p, signum, ps);
} else {
p->p_sisig = signum;
p->p_sitrapno = trapno; /* XXX for core dump/debugger */
p->p_sicode = code;
p->p_sigval = sigval;
/*
* Signals like SIGBUS and SIGSEGV should not, when
* generated by the kernel, be ignorable or blockable.
* If it is and we're not being traced, then just kill
* the process.
*/
if ((pr->ps_flags & PS_TRACED) == 0 &&
(sigprop[signum] & SA_KILL) &&
((p->p_sigmask & mask) || (ps->ps_sigignore & mask)))
sigexit(p, signum);
ptsignal(p, signum, STHREAD);
}
}
/*
* 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(struct proc *p, int signum)
{
ptsignal(p, signum, SPROCESS);
}
/*
* type = SPROCESS process signal, can be diverted (sigwait())
* type = STHREAD thread signal, but should be propagated if unhandled
* type = SPROPAGATED propagated to this thread, so don't propagate again
*/
void
ptsignal(struct proc *p, int signum, enum signal_type type)
{
int s, prop;
sig_t action;
int mask;
int *siglist;
struct process *pr = p->p_p;
struct proc *q;
int wakeparent = 0;
KERNEL_ASSERT_LOCKED();
#ifdef DIAGNOSTIC
if ((u_int)signum >= NSIG || signum == 0)
panic("psignal signal number");
#endif
/* Ignore signal if the target process is exiting */
if (pr->ps_flags & PS_EXITING)
return;
mask = sigmask(signum);
if (type == SPROCESS) {
/* Accept SIGKILL to coredumping processes */
if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) {
atomic_setbits_int(&pr->ps_siglist, mask);
return;
}
/*
* If the current thread can process the signal
* immediately (it's unblocked) then have it take it.
*/
q = curproc;
if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 &&
(q->p_sigmask & mask) == 0)
p = q;
else {
/*
* A process-wide signal can be diverted to a
* different thread that's in sigwait() for this
* signal. If there isn't such a thread, then
* pick a thread that doesn't have it blocked so
* that the stop/kill consideration isn't
* delayed. Otherwise, mark it pending on the
* main thread.
*/
TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) {
/* ignore exiting threads */
if (q->p_flag & P_WEXIT)
continue;
/* skip threads that have the signal blocked */
if ((q->p_sigmask & mask) != 0)
continue;
/* okay, could send to this thread */
p = q;
/*
* sigsuspend, sigwait, ppoll/pselect, etc?
* Definitely go to this thread, as it's
* already blocked in the kernel.
*/
if (q->p_flag & P_SIGSUSPEND)
break;
}
}
}
if (type != SPROPAGATED)
KNOTE(&pr->ps_klist, NOTE_SIGNAL | signum);
prop = sigprop[signum];
/*
* If proc is traced, always give parent a chance.
*/
if (pr->ps_flags & PS_TRACED) {
action = SIG_DFL;
} else {
/*
* If the signal is being ignored,
* then we forget about it immediately.
* (Note: we don't set SIGCONT in ps_sigignore,
* and if it is set to SIG_IGN,
* action will be SIG_DFL here.)
*/
if (pr->ps_sigacts->ps_sigignore & mask)
return;
if (p->p_sigmask & mask) {
action = SIG_HOLD;
} else if (pr->ps_sigacts->ps_sigcatch & mask) {
action = SIG_CATCH;
} else {
action = SIG_DFL;
if (prop & SA_KILL && pr->ps_nice > NZERO)
pr->ps_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 && pr->ps_pgrp->pg_jobc == 0)
return;
}
}
/*
* If delivered to process, mark as pending there. Continue and stop
* signals will be propagated to all threads. So they are always
* marked at thread level.
*/
siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist;
if (prop & SA_CONT) {
siglist = &p->p_siglist;
atomic_clearbits_int(siglist, stopsigmask);
}
if (prop & SA_STOP) {
siglist = &p->p_siglist;
atomic_clearbits_int(siglist, contsigmask);
atomic_clearbits_int(&p->p_flag, P_CONTINUED);
}
atomic_setbits_int(siglist, mask);
/*
* XXX delay processing of SA_STOP signals unless action == SIG_DFL?
*/
if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED)
TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link)
if (q != p)
ptsignal(q, signum, SPROPAGATED);
/*
* Defer further processing for signals which are held,
* except that stopped processes must be continued by SIGCONT.