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/* $OpenBSD: kern_sig.c,v 1.327 2024/05/08 13:05:33 claudio 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
*/
#include <sys/param.h>
#include <sys/signalvar.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/wait.h>
#include <sys/ktrace.h>
#include <sys/stat.h>
#include <sys/malloc.h>
#include <sys/pool.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/exec_elf.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <uvm/uvm_extern.h>
#include <machine/tcb.h>
int nosuidcoredump = 1;
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_flags = 0,
.f_attach = filt_sigattach,
.f_detach = filt_sigdetach,
.f_event = filt_signal,
};
/*
* The array below categorizes the signals and their default actions.
*/
const int sigprop[NSIG] = {
0, /* unused */
SA_KILL, /* SIGHUP */
SA_KILL, /* SIGINT */
SA_KILL|SA_CORE, /* SIGQUIT */
SA_KILL|SA_CORE, /* SIGILL */
SA_KILL|SA_CORE, /* SIGTRAP */
SA_KILL|SA_CORE, /* SIGABRT */
SA_KILL|SA_CORE, /* SIGEMT */
SA_KILL|SA_CORE, /* SIGFPE */
SA_KILL, /* SIGKILL */
SA_KILL|SA_CORE, /* SIGBUS */
SA_KILL|SA_CORE, /* SIGSEGV */
SA_KILL|SA_CORE, /* SIGSYS */
SA_KILL, /* SIGPIPE */
SA_KILL, /* SIGALRM */
SA_KILL, /* SIGTERM */
SA_IGNORE, /* SIGURG */
SA_STOP, /* SIGSTOP */
SA_STOP|SA_TTYSTOP, /* SIGTSTP */
SA_IGNORE|SA_CONT, /* SIGCONT */
SA_IGNORE, /* SIGCHLD */
SA_STOP|SA_TTYSTOP, /* SIGTTIN */
SA_STOP|SA_TTYSTOP, /* SIGTTOU */
SA_IGNORE, /* SIGIO */
SA_KILL, /* SIGXCPU */
SA_KILL, /* SIGXFSZ */
SA_KILL, /* SIGVTALRM */
SA_KILL, /* SIGPROF */
SA_IGNORE, /* SIGWINCH */
SA_IGNORE, /* SIGINFO */
SA_KILL, /* SIGUSR1 */
SA_KILL, /* SIGUSR2 */
SA_IGNORE, /* SIGTHR */
};
#define CONTSIGMASK (sigmask(SIGCONT))
#define STOPSIGMASK (sigmask(SIGSTOP) | sigmask(SIGTSTP) | \
sigmask(SIGTTIN) | sigmask(SIGTTOU))
void setsigvec(struct proc *, int, struct sigaction *);
void proc_stop(struct proc *p, int);
void proc_stop_sweep(void *);
void *proc_stop_si;
void setsigctx(struct proc *, int, struct sigctx *);
void postsig_done(struct proc *, int, sigset_t, int);
void postsig(struct proc *, int, struct sigctx *);
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)
{
proc_stop_si = softintr_establish(IPL_SOFTCLOCK, proc_stop_sweep,
NULL);
if (proc_stop_si == NULL)
panic("signal_init failed to register softintr");
pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE,
PR_WAITOK, "sigapl", NULL);
}
/*
* Initialize a new sigaltstack structure.
*/
void
sigstkinit(struct sigaltstack *ss)
{
ss->ss_flags = SS_DISABLE;
ss->ss_size = 0;
ss->ss_sp = NULL;
}
/*
* Create an initial sigacts structure, using the same signal state
* as pr.
*/
struct sigacts *
sigactsinit(struct process *pr)
{
struct sigacts *ps;
ps = pool_get(&sigacts_pool, PR_WAITOK);
memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts));
return (ps);
}
/*
* Release a sigacts structure.
*/
void
sigactsfree(struct sigacts *ps)
{
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) {
mtx_enter(&p->p_p->ps_mtx);
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_sigflags & SAS_NOCLDSTOP) != 0)
sa->sa_flags |= SA_NOCLDSTOP;
if ((ps->ps_sigflags & SAS_NOCLDWAIT) != 0)
sa->sa_flags |= SA_NOCLDWAIT;
}
mtx_leave(&p->p_p->ps_mtx);
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;
bit = sigmask(signum);
mtx_enter(&p->p_p->ps_mtx);
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_sigflags, SAS_NOCLDSTOP);
else
atomic_clearbits_int(&ps->ps_sigflags, 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_sigflags, SAS_NOCLDWAIT);
else
atomic_clearbits_int(&ps->ps_sigflags, 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;
}
mtx_leave(&p->p_p->ps_mtx);
}
/*
* Initialize signal state for process 0;
* set to ignore signals that are ignored by default.
*/
void
siginit(struct sigacts *ps)
{
int i;
for (i = 0; i < NSIG; i++)
if (sigprop[i] & SA_IGNORE && i != SIGCONT)
ps->ps_sigignore |= sigmask(i);
ps->ps_sigflags = SAS_NOCLDWAIT | SAS_NOCLDSTOP;
}
/*
* Reset signals for an exec by the specified thread.
*/
void
execsigs(struct proc *p)
{
struct sigacts *ps;
int nc, mask;
ps = p->p_p->ps_sigacts;
mtx_enter(&p->p_p->ps_mtx);
/*
* 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);
atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT);
if (ps->ps_sigact[SIGCHLD] == SIG_IGN)
ps->ps_sigact[SIGCHLD] = SIG_DFL;
mtx_leave(&p->p_p->ps_mtx);
}
/*
* 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;
KASSERT(p == curproc);
*retval = p->p_sigmask;
mask = SCARG(uap, mask) &~ sigcantmask;
switch (SCARG(uap, how)) {
case SIG_BLOCK:
SET(p->p_sigmask, mask);
break;
case SIG_UNBLOCK:
CLR(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;
p->p_sigmask = newmask;
atomic_setbits_int(&p->p_flag, P_SIGSUSPEND);
}
/*
* Suspend thread 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;
dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask);
while (tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigsusp", INFSLP) == 0)
continue;
/* 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);
p = tid ? tfind_user(tid, cp->p_p) : cp;
if (p == NULL)
return (ESRCH);
/* 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;
KERNEL_LOCK();
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);
KERNEL_UNLOCK();
}
/*
* Recalculate the signal mask and reset the signal disposition after
* usermode frame for delivery is formed.
*/
void
postsig_done(struct proc *p, int signum, sigset_t catchmask, int reset)
{
p->p_ru.ru_nsignals++;
SET(p->p_sigmask, catchmask);
if (reset != 0) {
sigset_t mask = sigmask(signum);
struct sigacts *ps = p->p_p->ps_sigacts;
mtx_enter(&p->p_p->ps_mtx);
ps->ps_sigcatch &= ~mask;
if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
ps->ps_sigignore |= mask;
ps->ps_sigact[signum] = SIG_DFL;
mtx_leave(&p->p_p->ps_mtx);
}
}
/*
* 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 sigctx ctx;
int mask;
switch (signum) {
case SIGILL:
if (code == ILL_BTCFI) {
pr->ps_acflag |= ABTCFI;
break;
}
/* FALLTHROUGH */
case SIGBUS:
case SIGSEGV:
pr->ps_acflag |= ATRAP;
break;
}
mask = sigmask(signum);
setsigctx(p, signum, &ctx);
if ((pr->ps_flags & PS_TRACED) == 0 && ctx.sig_catch != 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, ctx.sig_action,
p->p_sigmask, code, &si);
}
#endif
if (sendsig(ctx.sig_action, signum, p->p_sigmask, &si,
ctx.sig_info, ctx.sig_onstack)) {
KERNEL_LOCK();
sigexit(p, SIGILL);
/* NOTREACHED */
}
postsig_done(p, signum, ctx.sig_catchmask, ctx.sig_reset);
} else {
p->p_sisig = signum;
p->p_sitrapno = trapno; /* XXX for core dump/debugger */
p->p_sicode = code;
p->p_sigval = sigval;
/*
* If traced, stop if signal is masked, and stay stopped
* until released by the debugger. If our parent process
* is waiting for us, don't hang as we could deadlock.
*/
if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) &&
signum != SIGKILL && (p->p_sigmask & mask) != 0) {
int s;
single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT);
pr->ps_xsig = signum;
SCHED_LOCK(s);
proc_stop(p, 1);
SCHED_UNLOCK(s);
signum = pr->ps_xsig;
single_thread_clear(p, 0);
/*
* If we are no longer being traced, or the parent
* didn't give us a signal, skip sending the signal.
*/
if ((pr->ps_flags & PS_TRACED) == 0 ||
signum == 0)
return;
/* update signal info */
p->p_sisig = signum;
mask = sigmask(signum);
}
/*
* 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.
* After vfs_shutdown(9), init(8) cannot receive signals
* because new code pages of the signal handler cannot be
* mapped from halted storage. init(8) may not die or the
* kernel panics. Better loop between signal handler and
* page fault trap until the machine is halted.
*/
if ((pr->ps_flags & PS_TRACED) == 0 &&
(sigprop[signum] & SA_KILL) &&
((p->p_sigmask & mask) || ctx.sig_ignore) &&
pr->ps_pid != 1) {
KERNEL_LOCK();
sigexit(p, signum);
/* NOTREACHED */
}
KERNEL_LOCK();
ptsignal(p, signum, STHREAD);
KERNEL_UNLOCK();
}
}
/*
* 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, altaction = SIG_DFL;
sigset_t mask, sigmask;
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);
sigmask = READ_ONCE(p->p_sigmask);
if (type == SPROCESS) {
sigset_t tmpmask;
/* 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;
tmpmask = READ_ONCE(q->p_sigmask);
if (q->p_p == pr && (q->p_flag & P_WEXIT) == 0 &&
(tmpmask & mask) == 0) {
p = q;
sigmask = tmpmask;
} 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 */
tmpmask = READ_ONCE(q->p_sigmask);
if ((tmpmask & mask) != 0)
continue;
/* okay, could send to this thread */
p = q;
sigmask = tmpmask;
/*
* 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_locked(&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 {
sigset_t sigcatch, sigignore;
/*
* 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.)
*/
mtx_enter(&pr->ps_mtx);
sigignore = pr->ps_sigacts->ps_sigignore;
sigcatch = pr->ps_sigacts->ps_sigcatch;
mtx_leave(&pr->ps_mtx);
if (sigignore & mask)
return;
if (sigmask & mask) {
action = SIG_HOLD;
if (sigcatch & mask)
altaction = SIG_CATCH;
} else if (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 | SA_STOP))
siglist = &p->p_siglist;
/*
* 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);
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 cursig() and stop
* for the parent.
*/
if (pr->ps_flags & PS_TRACED)
goto run;
/*
* Recheck sigmask before waking up the process,
* there is a chance that while sending the signal
* the process changed sigmask and went to sleep.
*/
sigmask = READ_ONCE(p->p_sigmask);
if (sigmask & mask)
goto out;
else if (action == SIG_HOLD) {
/* signal got unmasked, get proper action */
action = altaction;
if (action == SIG_DFL) {
if (prop & SA_KILL && pr->ps_nice > NZERO)
pr->ps_nice = NZERO;
/*
* Discard tty stop signals sent to an
* orphaned process group, see above.
*/
if (prop & SA_TTYSTOP &&
pr->ps_pgrp->pg_jobc == 0) {
SCHED_UNLOCK(s);
return;
}
}
}
/*
* 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) {
mask = 0;
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 (pr->ps_flags & PS_PPWAIT)
goto out;
mask = 0;
pr->ps_xsig = signum;
proc_stop(p, 0);
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 (pr->ps_flags & PS_TRACED)
goto out;
/*
* Kill signal always sets processes running.
*/
if (signum == SIGKILL) {
atomic_clearbits_int(&p->p_flag, P_SUSPSIG);
goto runfast;
}
if (prop & SA_CONT) {
/*
* If SIGCONT is default (or ignored), we continue the
* process but don't leave the signal in p_siglist, as
* it has no further action. If SIGCONT is held, we
* continue the process and leave the signal in
* p_siglist. If the process catches SIGCONT, let it
* handle the signal itself. If it isn't waiting on
* an event, then it goes back to run state.
* Otherwise, process goes back to sleep state.
*/
atomic_setbits_int(&p->p_flag, P_CONTINUED);
atomic_clearbits_int(&p->p_flag, P_SUSPSIG);
wakeparent = 1;
if (action == SIG_DFL)
mask = 0;
if (action == SIG_CATCH)
goto runfast;
if (p->p_wchan == NULL)
goto run;
atomic_clearbits_int(&p->p_flag, P_WSLEEP);
p->p_stat = SSLEEP;
goto out;
}
/*
* Defer further processing for signals which are held,
* except that stopped processes must be continued by SIGCONT.
*/
if (action == SIG_HOLD)
goto out;
if (prop & SA_STOP) {
/*
* Already stopped, don't need to stop again.
* (If we did the shell could get confused.)
*/
mask = 0;
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_flag & P_SINTR)
unsleep(p);
goto out;
case SONPROC:
if (action == SIG_HOLD)
goto out;
/* set siglist before issuing the ast */
atomic_setbits_int(siglist, mask);
mask = 0;
signotify(p);
/* FALLTHROUGH */
default:
/*
* SRUN, SIDL, SDEAD do nothing with the signal,
* other than kicking ourselves if we are running.
* It will either never be noticed, or noticed very soon.
*/
goto out;
}
/* NOTREACHED */
runfast:
/*
* Raise priority to at least PUSER.
*/
if (p->p_usrpri > PUSER)
p->p_usrpri = PUSER;
run:
unsleep(p);
setrunnable(p);
out:
/* finally adjust siglist */
if (mask)
atomic_setbits_int(siglist, mask);
if (prop & SA_CONT) {
atomic_clearbits_int(siglist, STOPSIGMASK);
}
if (prop & SA_STOP) {
atomic_clearbits_int(siglist, CONTSIGMASK);
atomic_clearbits_int(&p->p_flag, P_CONTINUED);
}
SCHED_UNLOCK(s);
if (wakeparent)
wakeup(pr->ps_pptr);
}
/* fill the signal context which should be used by postsig() and issignal() */
void
setsigctx(struct proc *p, int signum, struct sigctx *sctx)
{
struct sigacts *ps = p->p_p->ps_sigacts;
sigset_t mask;
mtx_enter(&p->p_p->ps_mtx);
mask = sigmask(signum);
sctx->sig_action = ps->ps_sigact[signum];
sctx->sig_catchmask = ps->ps_catchmask[signum];
sctx->sig_reset = (ps->ps_sigreset & mask) != 0;
sctx->sig_info = (ps->ps_siginfo & mask) != 0;
sctx->sig_intr = (ps->ps_sigintr & mask) != 0;
sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0;
sctx->sig_ignore = (ps->ps_sigignore & mask) != 0;
sctx->sig_catch = (ps->ps_sigcatch & mask) != 0;
mtx_leave(&p->p_p->ps_mtx);
}
/*
* Determine signal that should be delivered to process p, the current
* process, 0 if none.
*
* 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. The normal call sequence is
*
* while (signum = cursig(curproc, &ctx))
* postsig(signum, &ctx);
*
* Assumes that if the P_SINTR flag is set, we're holding both the
* kernel and scheduler locks.
*/
int
cursig(struct proc *p, struct sigctx *sctx)
{
struct process *pr = p->p_p;
int signum, mask, prop;
sigset_t ps_siglist;
int s;
KASSERT(p == curproc);
for (;;) {
ps_siglist = READ_ONCE(pr->ps_siglist);
membar_consumer();
mask = SIGPENDING(p);
if (pr->ps_flags & PS_PPWAIT)
mask &= ~STOPSIGMASK;
if (mask == 0) /* no signal to send */
return (0);
signum = ffs((long)mask);
mask = sigmask(signum);
/* take the signal! */
if (atomic_cas_uint(&pr->ps_siglist, ps_siglist,
ps_siglist & ~mask) != ps_siglist) {
/* lost race taking the process signal, restart */
continue;
}
atomic_clearbits_int(&p->p_siglist, mask);
setsigctx(p, signum, sctx);
/*
* We should see pending but ignored signals
* only if PS_TRACED was on when they were posted.
*/
if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0)
continue;
/*
* If traced, always stop, and stay stopped until released
* by the debugger. If our parent process is waiting for
* us, don't hang as we could deadlock.
*/
if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) &&
signum != SIGKILL) {
single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT);
pr->ps_xsig = signum;
SCHED_LOCK(s);
proc_stop(p, 1);
SCHED_UNLOCK(s);
/*
* re-take the signal before releasing
* the other threads. Must check the continue
* conditions below and only take the signal if
* those are not true.
*/
signum = pr->ps_xsig;
mask = sigmask(signum);
setsigctx(p, signum, sctx);
if (!((pr->ps_flags & PS_TRACED) == 0 ||
signum == 0 ||
(p->p_sigmask & mask) != 0)) {
atomic_clearbits_int(&p->p_siglist, mask);
atomic_clearbits_int(&pr->ps_siglist, mask);
}
single_thread_clear(p, 0);
/*
* If we are no longer being traced, or the parent
* didn't give us a signal, look for more signals.
*/
if ((pr->ps_flags & PS_TRACED) == 0 ||
signum == 0)
continue;
/*
* If the new signal is being masked, look for other
* signals.
*/
if ((p->p_sigmask & mask) != 0)
continue;
}
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)sctx->sig_action) {
case (long)SIG_DFL:
/*
* Don't take default actions on system processes.
*/
if (pr->ps_pid <= 1) {
#ifdef DIAGNOSTIC
/*
* Are you sure you want to ignore SIGSEGV
* in init? XXX
*/
printf("Process (pid %d) got signal"
" %d\n", pr->ps_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 (pr->ps_flags & PS_TRACED ||
(pr->ps_pgrp->pg_jobc == 0 &&
prop & SA_TTYSTOP))
break; /* == ignore */
pr->ps_xsig = signum;
SCHED_LOCK(s);
proc_stop(p, 1);
SCHED_UNLOCK(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 &&
(pr->ps_flags & PS_TRACED) == 0)
printf("%s\n", __func__);
break; /* == ignore */
default:
/*
* This signal has an action, let
* postsig() process it.
*/
goto keep;
}
}
/* NOTREACHED */
keep:
atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */
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 sw)
{
struct process *pr = p->p_p;
#ifdef MULTIPROCESSOR
SCHED_ASSERT_LOCKED();
#endif
/* do not stop exiting procs */
if (ISSET(p->p_flag, P_WEXIT))
return;
p->p_stat = SSTOP;
atomic_clearbits_int(&pr->ps_flags, PS_WAITED);
atomic_setbits_int(&pr->ps_flags, PS_STOPPED);
atomic_setbits_int(&p->p_flag, P_SUSPSIG);
/*
* We need this soft interrupt to be handled fast.
* Extra calls to softclock don't hurt.
*/
softintr_schedule(proc_stop_si);
if (sw)
mi_switch();
}
/*
* Called from a soft interrupt to send signals to the parents of stopped
* processes.
* We can't do this in proc_stop because it's called with nasty locks held
* and we would need recursive scheduler lock to deal with that.
*/
void
proc_stop_sweep(void *v)
{
struct process *pr;
LIST_FOREACH(pr, &allprocess, ps_list) {
if ((pr->ps_flags & PS_STOPPED) == 0)
continue;
atomic_clearbits_int(&pr->ps_flags, PS_STOPPED);
if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0)
prsignal(pr->ps_pptr, SIGCHLD);
wakeup(pr->ps_pptr);
}
}
/*
* Take the action for the specified signal
* from the current set of pending signals.
*/
void
postsig(struct proc *p, int signum, struct sigctx *sctx)
{
u_long trapno;
int mask, returnmask;
siginfo_t si;
union sigval sigval;
int code;
KASSERT(signum != 0);
mask = sigmask(signum);
atomic_clearbits_int(&p->p_siglist, mask);
sigval.sival_ptr = NULL;
if (p->p_sisig != signum) {
trapno = 0;
code = SI_USER;
sigval.sival_ptr = NULL;
} else {
trapno = p->p_sitrapno;
code = p->p_sicode;
sigval = p->p_sigval;
}
initsiginfo(&si, signum, trapno, code, sigval);
#ifdef KTRACE
if (KTRPOINT(p, KTR_PSIG)) {
ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ?
p->p_oldmask : p->p_sigmask, code, &si);
}
#endif
if (sctx->sig_action == SIG_DFL) {
/*
* Default action, where the default is to kill
* the process. (Other cases were ignored above.)
*/
KERNEL_LOCK();
sigexit(p, signum);
/* NOTREACHED */
} else {
/*
* If we get here, the signal must be caught.
*/
#ifdef DIAGNOSTIC
if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask))
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_flag & P_SIGSUSPEND) {
atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND);
returnmask = p->p_oldmask;
} else {
returnmask = p->p_sigmask;
}
if (p->p_sisig == signum) {
p->p_sisig = 0;
p->p_sitrapno = 0;
p->p_sicode = SI_USER;
p->p_sigval.sival_ptr = NULL;
}
if (sendsig(sctx->sig_action, signum, returnmask, &si,
sctx->sig_info, sctx->sig_onstack)) {
KERNEL_LOCK();
sigexit(p, SIGILL);
/* NOTREACHED */
}
postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset);
}
}
/*
* Force the current process to exit with the specified signal, dumping core
* if appropriate. We bypass the normal tests for masked and caught signals,
* allowing unrecoverable failures to terminate the process without changing
* signal state. Mark the accounting record with the signal termination.
* If dumping core, save the signal number for the debugger. Calls exit and
* does not return.
*/
void
sigexit(struct proc *p, int signum)
{
/* Mark process as going away */
atomic_setbits_int(&p->p_flag, P_WEXIT);
p->p_p->ps_acflag |= AXSIG;
if (sigprop[signum] & SA_CORE) {
p->p_sisig = signum;
/* if there are other threads, pause them */
if (P_HASSIBLING(p))
single_thread_set(p, SINGLE_UNWIND);
if (coredump(p) == 0)
signum |= WCOREFLAG;
}
exit1(p, 0, signum, EXIT_NORMAL);
/* NOTREACHED */
}
/*
* Send uncatchable SIGABRT for coredump.
*/
void
sigabort(struct proc *p)
{
struct sigaction sa;
KASSERT(p == curproc || panicstr || db_active);
memset(&sa, 0, sizeof sa);
sa.sa_handler = SIG_DFL;
setsigvec(p, SIGABRT, &sa);
CLR(p->p_sigmask, sigmask(SIGABRT));
psignal(p, SIGABRT);
}
/*
* Return 1 if `sig', a given signal, is ignored or masked for `p', a given
* thread, and 0 otherwise.
*/
int
sigismasked(struct proc *p, int sig)
{
struct process *pr = p->p_p;
int rv;
KASSERT(p == curproc);
mtx_enter(&pr->ps_mtx);
rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) ||
(p->p_sigmask & sigmask(sig));
mtx_leave(&pr->ps_mtx);
return !!rv;
}
struct coredump_iostate {
struct proc *io_proc;
struct vnode *io_vp;
struct ucred *io_cred;
off_t io_offset;
};
/*
* Dump core, into a file named "progname.core", unless the process was
* setuid/setgid.
*/
int
coredump(struct proc *p)
{
#ifdef SMALL_KERNEL
return EPERM;
#else
struct process *pr = p->p_p;
struct vnode *vp;
struct ucred *cred = p->p_ucred;
struct vmspace *vm = p->p_vmspace;
struct nameidata nd;
struct vattr vattr;
struct coredump_iostate io;
int error, len, incrash = 0;
char *name;
const char *dir = "/var/crash";
atomic_setbits_int(&pr->ps_flags, PS_COREDUMP);
#ifdef PMAP_CHECK_COPYIN
/* disable copyin checks, so we can write out text sections if needed */
p->p_vmspace->vm_map.check_copyin_count = 0;
#endif
/* Don't dump if will exceed file size limit. */
if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE))
return (EFBIG);
name = pool_get(&namei_pool, PR_WAITOK);
/*
* If the process has inconsistent uids, nosuidcoredump
* determines coredump placement policy.
*/
if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) ||
((pr->ps_flags & PS_SUGID) && nosuidcoredump)) {
if (nosuidcoredump == 3) {
/*
* If the program directory does not exist, dumps of
* that core will silently fail.
*/
len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core",
dir, pr->ps_comm, pr->ps_pid);
incrash = KERNELPATH;
} else if (nosuidcoredump == 2) {
len = snprintf(name, MAXPATHLEN, "%s/%s.core",
dir, pr->ps_comm);
incrash = KERNELPATH;
} else {
pool_put(&namei_pool, name);
return (EPERM);
}
} else
len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm);
if (len >= MAXPATHLEN) {
pool_put(&namei_pool, name);
return (EACCES);
}
/*
* Control the UID used to write out. The normal case uses
* the real UID. If the sugid case is going to write into the
* controlled directory, we do so as root.
*/
if (incrash == 0) {
cred = crdup(cred);
cred->cr_uid = cred->cr_ruid;
cred->cr_gid = cred->cr_rgid;
} else {
if (p->p_fd->fd_rdir) {
vrele(p->p_fd->fd_rdir);
p->p_fd->fd_rdir = NULL;
}
p->p_ucred = crdup(p->p_ucred);
crfree(cred);
cred = p->p_ucred;
crhold(cred);
cred->cr_uid = 0;
cred->cr_gid = 0;
}
/* incrash should be 0 or KERNELPATH only */
NDINIT(&nd, 0, BYPASSUNVEIL | incrash, UIO_SYSSPACE, name, p);
error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK,
S_IRUSR | S_IWUSR);
if (error)
goto out;
/*
* Don't dump to non-regular files, files with links, or files
* owned by someone else.
*/
vp = nd.ni_vp;
if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) {
VOP_UNLOCK(vp);
vn_close(vp, FWRITE, cred, p);
goto out;
}
if (vp->v_type != VREG || vattr.va_nlink != 1 ||
vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) ||
vattr.va_uid != cred->cr_uid) {
error = EACCES;
VOP_UNLOCK(vp);
vn_close(vp, FWRITE, cred, p);
goto out;
}
VATTR_NULL(&vattr);
vattr.va_size = 0;
VOP_SETATTR(vp, &vattr, cred, p);
pr->ps_acflag |= ACORE;
io.io_proc = p;
io.io_vp = vp;
io.io_cred = cred;
io.io_offset = 0;
VOP_UNLOCK(vp);
vref(vp);
error = vn_close(vp, FWRITE, cred, p);
if (error == 0)
error = coredump_elf(p, &io);
vrele(vp);
out:
crfree(cred);
pool_put(&namei_pool, name);
return (error);
#endif
}
#ifndef SMALL_KERNEL
int
coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len,
int isvnode)
{
struct coredump_iostate *io = cookie;
off_t coffset = 0;
size_t csize;
int chunk, error;
csize = len;
do {
if (sigmask(SIGKILL) &
(io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist))
return (EINTR);
/* Rest of the loop sleeps with lock held, so... */
yield();
chunk = MIN(csize, MAXPHYS);
error = vn_rdwr(UIO_WRITE, io->io_vp,
(caddr_t)data + coffset, chunk,
io->io_offset + coffset, segflg,
IO_UNIT, io->io_cred, NULL, io->io_proc);
if (error && (error != EFAULT || !isvnode)) {
struct process *pr = io->io_proc->p_p;
if (error == ENOSPC)
log(LOG_ERR,
"coredump of %s(%d) failed, filesystem full\n",
pr->ps_comm, pr->ps_pid);
else
log(LOG_ERR,
"coredump of %s(%d), write failed: errno %d\n",
pr->ps_comm, pr->ps_pid, error);
return (error);
}
coffset += chunk;
csize -= chunk;
} while (csize > 0);
io->io_offset += len;
return (0);
}
void
coredump_unmap(void *cookie, vaddr_t start, vaddr_t end)
{
struct coredump_iostate *io = cookie;
uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end);
}
#endif /* !SMALL_KERNEL */
/*
* Nonexistent system call-- signal process (may want to handle it).
* Flag error in case process won't see signal immediately (blocked or ignored).
*/
int
sys_nosys(struct proc *p, void *v, register_t *retval)
{
ptsignal(p, SIGSYS, STHREAD);
return (ENOSYS);
}
int
sys___thrsigdivert(struct proc *p, void *v, register_t *retval)
{
struct sys___thrsigdivert_args /* {
syscallarg(sigset_t) sigmask;
syscallarg(siginfo_t *) info;
syscallarg(const struct timespec *) timeout;
} */ *uap = v;
struct sigctx ctx;
sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask;
siginfo_t si;
uint64_t nsecs = INFSLP;
int timeinvalid = 0;
int error = 0;
memset(&si, 0, sizeof(si));
if (SCARG(uap, timeout) != NULL) {
struct timespec ts;
if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0)
return (error);
#ifdef KTRACE
if (KTRPOINT(p, KTR_STRUCT))
ktrreltimespec(p, &ts);
#endif
if (!timespecisvalid(&ts))
timeinvalid = 1;
else
nsecs = TIMESPEC_TO_NSEC(&ts);
}
dosigsuspend(p, p->p_sigmask &~ mask);
for (;;) {
si.si_signo = cursig(p, &ctx);
if (si.si_signo != 0) {
sigset_t smask = sigmask(si.si_signo);
if (smask & mask) {
atomic_clearbits_int(&p->p_siglist, smask);
error = 0;
break;
}
}
/* per-POSIX, delay this error until after the above */
if (timeinvalid)
error = EINVAL;
/* per-POSIX, return immediately if timeout is zero-valued */
if (nsecs == 0)
error = EAGAIN;
if (error != 0)
break;
error = tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigwait", nsecs);
}
if (error == 0) {
*retval = si.si_signo;
if (SCARG(uap, info) != NULL) {
error = copyout(&si, SCARG(uap, info), sizeof(si));
#ifdef KTRACE
if (error == 0 && KTRPOINT(p, KTR_STRUCT))
ktrsiginfo(p, &si);
#endif
}
} else if (error == ERESTART && SCARG(uap, timeout) != NULL) {
/*
* Restarting is wrong if there's a timeout, as it'll be
* for the same interval again
*/
error = EINTR;
}
return (error);
}
void
initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val)
{
memset(si, 0, sizeof(*si));
si->si_signo = sig;
si->si_code = code;
if (code == SI_USER) {
si->si_value = val;
} else {
switch (sig) {
case SIGSEGV:
case SIGILL:
case SIGBUS:
case SIGFPE:
si->si_addr = val.sival_ptr;
si->si_trapno = trapno;
break;
case SIGXFSZ:
break;
}
}
}
int
filt_sigattach(struct knote *kn)
{
struct process *pr = curproc->p_p;
int s;
if (kn->kn_id >= NSIG)
return EINVAL;
kn->kn_ptr.p_process = pr;
kn->kn_flags |= EV_CLEAR; /* automatically set */
s = splhigh();
klist_insert_locked(&pr->ps_klist, kn);
splx(s);
return (0);
}
void
filt_sigdetach(struct knote *kn)
{
struct process *pr = kn->kn_ptr.p_process;
int s;
s = splhigh();
klist_remove_locked(&pr->ps_klist, kn);
splx(s);
}
/*
* 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.
*/
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);
}
void
userret(struct proc *p)
{
struct sigctx ctx;
int signum;
if (p->p_flag & P_SUSPSINGLE)
single_thread_check(p, 0);
/* send SIGPROF or SIGVTALRM if their timers interrupted this thread */
if (p->p_flag & P_PROFPEND) {
atomic_clearbits_int(&p->p_flag, P_PROFPEND);
KERNEL_LOCK();
psignal(p, SIGPROF);
KERNEL_UNLOCK();
}
if (p->p_flag & P_ALRMPEND) {
atomic_clearbits_int(&p->p_flag, P_ALRMPEND);
KERNEL_LOCK();
psignal(p, SIGVTALRM);
KERNEL_UNLOCK();
}
if (SIGPENDING(p) != 0) {
while ((signum = cursig(p, &ctx)) != 0)
postsig(p, signum, &ctx);
}
/*
* If P_SIGSUSPEND is still set here, then we still need to restore
* the original sigmask before returning to userspace. Also, this
* might unmask some pending signals, so we need to check a second
* time for signals to post.
*/
if (p->p_flag & P_SIGSUSPEND) {
p->p_sigmask = p->p_oldmask;
atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND);
while ((signum = cursig(p, &ctx)) != 0)
postsig(p, signum, &ctx);
}
WITNESS_WARN(WARN_PANIC, NULL, "userret: returning");
p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri;
}
int
single_thread_check_locked(struct proc *p, int deep, int s)
{
struct process *pr = p->p_p;
SCHED_ASSERT_LOCKED();
if (pr->ps_single == NULL || pr->ps_single == p)
return (0);
do {
/* if we're in deep, we need to unwind to the edge */
if (deep) {
if (pr->ps_flags & PS_SINGLEUNWIND)
return (ERESTART);
if (pr->ps_flags & PS_SINGLEEXIT)
return (EINTR);
}
if (atomic_dec_int_nv(&pr->ps_singlecount) == 0)
wakeup(&pr->ps_singlecount);
if (pr->ps_flags & PS_SINGLEEXIT) {
SCHED_UNLOCK(s);
KERNEL_LOCK();
exit1(p, 0, 0, EXIT_THREAD_NOCHECK);
/* NOTREACHED */
}
/* not exiting and don't need to unwind, so suspend */
p->p_stat = SSTOP;
mi_switch();
} while (pr->ps_single != NULL);
return (0);
}
int
single_thread_check(struct proc *p, int deep)
{
int s, error;
SCHED_LOCK(s);
error = single_thread_check_locked(p, deep, s);
SCHED_UNLOCK(s);
return error;
}
/*
* Stop other threads in the process. The mode controls how and
* where the other threads should stop:
* - SINGLE_SUSPEND: stop wherever they are, will later be released (via
* single_thread_clear())
* - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit
* (by setting to SINGLE_EXIT) or released as with SINGLE_SUSPEND
* - SINGLE_EXIT: unwind to kernel boundary and exit
*/
int
single_thread_set(struct proc *p, int flags)
{
struct process *pr = p->p_p;
struct proc *q;
int error, s, mode = flags & SINGLE_MASK;
KASSERT(curproc == p);
SCHED_LOCK(s);
error = single_thread_check_locked(p, flags & SINGLE_DEEP, s);
if (error) {
SCHED_UNLOCK(s);
return error;
}
switch (mode) {
case SINGLE_SUSPEND:
break;
case SINGLE_UNWIND:
atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND);
break;
case SINGLE_EXIT:
atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT);
atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND);
break;
#ifdef DIAGNOSTIC
default:
panic("single_thread_mode = %d", mode);
#endif
}
pr->ps_singlecount = 0;
membar_producer();
pr->ps_single = p;
TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) {
if (q == p)
continue;
if (q->p_flag & P_WEXIT) {
if (mode == SINGLE_EXIT) {
if (q->p_stat == SSTOP) {
unsleep(q);
setrunnable(q);
atomic_inc_int(&pr->ps_singlecount);
}
}
continue;
}
atomic_setbits_int(&q->p_flag, P_SUSPSINGLE);
switch (q->p_stat) {
case SIDL:
case SRUN:
atomic_inc_int(&pr->ps_singlecount);
break;
case SSLEEP:
/* if it's not interruptible, then just have to wait */
if (q->p_flag & P_SINTR) {
/* merely need to suspend? just stop it */
if (mode == SINGLE_SUSPEND) {
q->p_stat = SSTOP;
break;
}
/* need to unwind or exit, so wake it */
unsleep(q);
setrunnable(q);
}
atomic_inc_int(&pr->ps_singlecount);
break;
case SSTOP:
if (mode == SINGLE_EXIT) {
unsleep(q);
setrunnable(q);
atomic_inc_int(&pr->ps_singlecount);
}
break;
case SDEAD:
break;
case SONPROC:
atomic_inc_int(&pr->ps_singlecount);
signotify(q);
break;
}
}
SCHED_UNLOCK(s);
if ((flags & SINGLE_NOWAIT) == 0)
single_thread_wait(pr, 1);
return 0;
}
/*
* Wait for other threads to stop. If recheck is false then the function
* returns non-zero if the caller needs to restart the check else 0 is
* returned. If recheck is true the return value is always 0.
*/
int
single_thread_wait(struct process *pr, int recheck)
{
int wait;
/* wait until they're all suspended */
wait = pr->ps_singlecount > 0;
while (wait) {
sleep_setup(&pr->ps_singlecount, PWAIT, "suspend");
wait = pr->ps_singlecount > 0;
sleep_finish(0, wait);
if (!recheck)
break;
}
return wait;
}
void
single_thread_clear(struct proc *p, int flag)
{
struct process *pr = p->p_p;
struct proc *q;
int s;
KASSERT(pr->ps_single == p);
KASSERT(curproc == p);
SCHED_LOCK(s);
pr->ps_single = NULL;
atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT);
TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) {
if (q == p || (q->p_flag & P_SUSPSINGLE) == 0)
continue;
atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE);
/*
* if the thread was only stopped for single threading
* then clearing that either makes it runnable or puts
* it back into some sleep queue
*/
if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) {
if (q->p_wchan == NULL)
setrunnable(q);
else {
atomic_clearbits_int(&q->p_flag, P_WSLEEP);
q->p_stat = SSLEEP;
}
}
}
SCHED_UNLOCK(s);
}
void
sigio_del(struct sigiolst *rmlist)
{
struct sigio *sigio;
while ((sigio = LIST_FIRST(rmlist)) != NULL) {
LIST_REMOVE(sigio, sio_pgsigio);
crfree(sigio->sio_ucred);
free(sigio, M_SIGIO, sizeof(*sigio));
}
}
void
sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist)
{
struct sigio *sigio;
MUTEX_ASSERT_LOCKED(&sigio_lock);
sigio = sir->sir_sigio;
if (sigio != NULL) {
KASSERT(sigio->sio_myref == sir);
sir->sir_sigio = NULL;
if (sigio->sio_pgid > 0)
sigio->sio_proc = NULL;
else
sigio->sio_pgrp = NULL;
LIST_REMOVE(sigio, sio_pgsigio);
LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio);
}
}
void
sigio_free(struct sigio_ref *sir)
{
struct sigiolst rmlist;
if (sir->sir_sigio == NULL)
return;
LIST_INIT(&rmlist);
mtx_enter(&sigio_lock);
sigio_unlink(sir, &rmlist);
mtx_leave(&sigio_lock);
sigio_del(&rmlist);
}
void
sigio_freelist(struct sigiolst *sigiolst)
{
struct sigiolst rmlist;
struct sigio *sigio;
if (LIST_EMPTY(sigiolst))
return;
LIST_INIT(&rmlist);
mtx_enter(&sigio_lock);
while ((sigio = LIST_FIRST(sigiolst)) != NULL)
sigio_unlink(sigio->sio_myref, &rmlist);
mtx_leave(&sigio_lock);
sigio_del(&rmlist);
}
int
sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data)
{
struct sigiolst rmlist;
struct proc *p = curproc;
struct pgrp *pgrp = NULL;
struct process *pr = NULL;
struct sigio *sigio;
int error;
pid_t pgid = *(int *)data;
if (pgid == 0) {
sigio_free(sir);
return (0);
}
if (cmd == TIOCSPGRP) {
if (pgid < 0)
return (EINVAL);
pgid = -pgid;
}
sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK);
sigio->sio_pgid = pgid;
sigio->sio_ucred = crhold(p->p_ucred);
sigio->sio_myref = sir;
LIST_INIT(&rmlist);
/*
* The kernel lock, and not sleeping between prfind()/pgfind() and
* linking of the sigio ensure that the process or process group does
* not disappear unexpectedly.
*/
KERNEL_LOCK();
mtx_enter(&sigio_lock);
if (pgid > 0) {
pr = prfind(pgid);
if (pr == NULL) {
error = ESRCH;
goto fail;
}
/*
* Policy - Don't allow a process to FSETOWN a process
* in another session.
*
* Remove this test to allow maximum flexibility or
* restrict FSETOWN to the current process or process
* group for maximum safety.
*/
if (pr->ps_session != p->p_p->ps_session) {
error = EPERM;
goto fail;
}
if ((pr->ps_flags & PS_EXITING) != 0) {
error = ESRCH;
goto fail;
}
} else /* if (pgid < 0) */ {
pgrp = pgfind(-pgid);
if (pgrp == NULL) {
error = ESRCH;
goto fail;
}
/*
* Policy - Don't allow a process to FSETOWN a process
* in another session.
*
* Remove this test to allow maximum flexibility or
* restrict FSETOWN to the current process or process
* group for maximum safety.
*/
if (pgrp->pg_session != p->p_p->ps_session) {
error = EPERM;
goto fail;
}
}
if (pgid > 0) {
sigio->sio_proc = pr;
LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio);
} else {
sigio->sio_pgrp = pgrp;
LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
}
sigio_unlink(sir, &rmlist);
sir->sir_sigio = sigio;
mtx_leave(&sigio_lock);
KERNEL_UNLOCK();
sigio_del(&rmlist);
return (0);
fail:
mtx_leave(&sigio_lock);
KERNEL_UNLOCK();
crfree(sigio->sio_ucred);
free(sigio, M_SIGIO, sizeof(*sigio));
return (error);
}
void
sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data)
{
struct sigio *sigio;
pid_t pgid = 0;
mtx_enter(&sigio_lock);
sigio = sir->sir_sigio;
if (sigio != NULL)
pgid = sigio->sio_pgid;
mtx_leave(&sigio_lock);
if (cmd == TIOCGPGRP)
pgid = -pgid;
*(int *)data = pgid;
}
void
sigio_copy(struct sigio_ref *dst, struct sigio_ref *src)
{
struct sigiolst rmlist;
struct sigio *newsigio, *sigio;
sigio_free(dst);
if (src->sir_sigio == NULL)
return;
newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK);
LIST_INIT(&rmlist);
mtx_enter(&sigio_lock);
sigio = src->sir_sigio;
if (sigio == NULL) {
mtx_leave(&sigio_lock);
free(newsigio, M_SIGIO, sizeof(*newsigio));
return;
}
newsigio->sio_pgid = sigio->sio_pgid;
newsigio->sio_ucred = crhold(sigio->sio_ucred);
newsigio->sio_myref = dst;
if (newsigio->sio_pgid > 0) {
newsigio->sio_proc = sigio->sio_proc;
LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio,
sio_pgsigio);
} else {
newsigio->sio_pgrp = sigio->sio_pgrp;
LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio,
sio_pgsigio);
}
sigio_unlink(dst, &rmlist);
dst->sir_sigio = newsigio;
mtx_leave(&sigio_lock);
sigio_del(&rmlist);
}
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