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Diffstat (limited to 'usr/src/uts/common/os/sig.c')
-rw-r--r--usr/src/uts/common/os/sig.c100
1 files changed, 84 insertions, 16 deletions
diff --git a/usr/src/uts/common/os/sig.c b/usr/src/uts/common/os/sig.c
index 453b1f22d4..67a93581dd 100644
--- a/usr/src/uts/common/os/sig.c
+++ b/usr/src/uts/common/os/sig.c
@@ -22,7 +22,7 @@
/*
* Copyright 2010 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
- * Copyright (c) 2014, Joyent, Inc. All rights reserved.
+ * Copyright 2017, Joyent, Inc.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
@@ -60,6 +60,7 @@
#include <sys/cyclic.h>
#include <sys/dtrace.h>
#include <sys/sdt.h>
+#include <sys/brand.h>
#include <sys/signalfd.h>
const k_sigset_t nullsmask = {0, 0, 0};
@@ -148,6 +149,21 @@ signal_is_blocked(kthread_t *t, int sig)
}
/*
+ * Return true if the signal can safely be ignored.
+ * That is, if the signal is included in the p_ignore mask and doing so is not
+ * forbidden by any process branding.
+ */
+static int
+sig_ignorable(proc_t *p, klwp_t *lwp, int sig)
+{
+ return (sigismember(&p->p_ignore, sig) && /* sig in ignore mask */
+ !(PROC_IS_BRANDED(p) && /* allowed by brand */
+ BROP(p)->b_sig_ignorable != NULL &&
+ BROP(p)->b_sig_ignorable(p, lwp, sig) == B_FALSE));
+
+}
+
+/*
* Return true if the signal can safely be discarded on generation.
* That is, if there is no need for the signal on the receiving end.
* The answer is true if the process is a zombie or
@@ -159,12 +175,13 @@ signal_is_blocked(kthread_t *t, int sig)
* the signal is not being accepted via sigwait()
*/
static int
-sig_discardable(proc_t *p, int sig)
+sig_discardable(proc_t *p, kthread_t *tp, int sig)
{
kthread_t *t = p->p_tlist;
+ klwp_t *lwp = (tp == NULL) ? NULL : tp->t_lwp;
return (t == NULL || /* if zombie or ... */
- (sigismember(&p->p_ignore, sig) && /* signal is ignored */
+ (sig_ignorable(p, lwp, sig) && /* signal is ignored */
t->t_forw == t && /* and single-threaded */
!tracing(p, sig) && /* and no /proc tracing */
!signal_is_blocked(t, sig) && /* and signal not blocked */
@@ -200,7 +217,7 @@ eat_signal(kthread_t *t, int sig)
!(ttoproc(t)->p_proc_flag & P_PR_LOCK)) {
ttoproc(t)->p_stopsig = 0;
t->t_dtrace_stop = 0;
- t->t_schedflag |= TS_XSTART | TS_PSTART;
+ t->t_schedflag |= TS_XSTART | TS_PSTART | TS_BSTART;
setrun_locked(t);
} else if (t != curthread && t->t_state == TS_ONPROC) {
aston(t); /* make it do issig promptly */
@@ -297,7 +314,7 @@ sigtoproc(proc_t *p, kthread_t *t, int sig)
}
}
- if (sig_discardable(p, sig)) {
+ if (sig_discardable(p, t, sig)) {
DTRACE_PROC3(signal__discard, kthread_t *, p->p_tlist,
proc_t *, p, int, sig);
return;
@@ -497,7 +514,7 @@ issig_justlooking(void)
if (sigismember(&set, sig) &&
(tracing(p, sig) ||
sigismember(&t->t_sigwait, sig) ||
- !sigismember(&p->p_ignore, sig))) {
+ !sig_ignorable(p, lwp, sig))) {
/*
* Don't promote a signal that will stop
* the process when lwp_nostop is set.
@@ -623,6 +640,28 @@ issig_forreal(void)
}
/*
+ * The brand hook name 'b_issig_stop' is a misnomer.
+ * Allow the brand the chance to alter (or suppress) delivery
+ * of this signal.
+ */
+ if (PROC_IS_BRANDED(p) && BROP(p)->b_issig_stop != NULL) {
+ int r;
+
+ /*
+ * The brand hook will return 0 if it would like
+ * us to drive on, -1 if we should restart
+ * the loop to check other conditions, or 1 if we
+ * should terminate the loop.
+ */
+ r = BROP(p)->b_issig_stop(p, lwp);
+ if (r < 0) {
+ continue;
+ } else if (r > 0) {
+ break;
+ }
+ }
+
+ /*
* Honor requested stop before dealing with the
* current signal; a debugger may change it.
* Do not want to go back to loop here since this is a special
@@ -656,7 +695,7 @@ issig_forreal(void)
lwp->lwp_cursig = 0;
lwp->lwp_extsig = 0;
if (sigismember(&t->t_sigwait, sig) ||
- (!sigismember(&p->p_ignore, sig) &&
+ (!sig_ignorable(p, lwp, sig) &&
!isjobstop(sig))) {
if (p->p_flag & (SEXITLWPS|SKILLED)) {
sig = SIGKILL;
@@ -708,7 +747,7 @@ issig_forreal(void)
toproc = 0;
if (tracing(p, sig) ||
sigismember(&t->t_sigwait, sig) ||
- !sigismember(&p->p_ignore, sig)) {
+ !sig_ignorable(p, lwp, sig)) {
if (sigismember(&t->t_extsig, sig))
ext = 1;
break;
@@ -722,7 +761,7 @@ issig_forreal(void)
toproc = 1;
if (tracing(p, sig) ||
sigismember(&t->t_sigwait, sig) ||
- !sigismember(&p->p_ignore, sig)) {
+ !sig_ignorable(p, lwp, sig)) {
if (sigismember(&p->p_extsig, sig))
ext = 1;
break;
@@ -954,6 +993,16 @@ stop(int why, int what)
}
break;
+ case PR_BRAND:
+ /*
+ * We have been stopped by the brand code for a brand-private
+ * reason. This is an asynchronous stop affecting only this
+ * LWP.
+ */
+ VERIFY(PROC_IS_BRANDED(p));
+ flags &= ~TS_BSTART;
+ break;
+
default: /* /proc stop */
flags &= ~TS_PSTART;
/*
@@ -1065,7 +1114,7 @@ stop(int why, int what)
}
}
- if (why != PR_JOBCONTROL && why != PR_CHECKPOINT) {
+ if (why != PR_JOBCONTROL && why != PR_CHECKPOINT && why != PR_BRAND) {
/*
* Do process-level notification when all lwps are
* either stopped on events of interest to /proc
@@ -1171,6 +1220,13 @@ stop(int why, int what)
if (why == PR_CHECKPOINT)
del_one_utstop();
+ /*
+ * Allow the brand to post notification of this stop condition.
+ */
+ if (PROC_IS_BRANDED(p) && BROP(p)->b_stop_notify != NULL) {
+ BROP(p)->b_stop_notify(p, lwp, why, what);
+ }
+
thread_lock(t);
ASSERT((t->t_schedflag & TS_ALLSTART) == 0);
t->t_schedflag |= flags;
@@ -1192,7 +1248,7 @@ stop(int why, int what)
(p->p_flag & (SEXITLWPS|SKILLED))) {
p->p_stopsig = 0;
thread_lock(t);
- t->t_schedflag |= TS_XSTART | TS_PSTART;
+ t->t_schedflag |= TS_XSTART | TS_PSTART | TS_BSTART;
setrun_locked(t);
thread_unlock_nopreempt(t);
} else if (why == PR_JOBCONTROL) {
@@ -1327,7 +1383,7 @@ psig(void)
* this signal from pending to current (we dropped p->p_lock).
* This can happen only in a multi-threaded process.
*/
- if (sigismember(&p->p_ignore, sig) ||
+ if (sig_ignorable(p, lwp, sig) ||
(func == SIG_DFL && sigismember(&stopdefault, sig))) {
lwp->lwp_cursig = 0;
lwp->lwp_extsig = 0;
@@ -1771,9 +1827,12 @@ post_sigcld(proc_t *cp, sigqueue_t *sqp)
/*
* This can only happen when the parent is init.
* (See call to sigcld(q, NULL) in exit().)
- * Use KM_NOSLEEP to avoid deadlock.
+ * Use KM_NOSLEEP to avoid deadlock. The child procs
+ * initpid can be 1 for zlogin.
*/
- ASSERT(pp == proc_init);
+ ASSERT(pp->p_pidp->pid_id ==
+ cp->p_zone->zone_proc_initpid ||
+ pp->p_pidp->pid_id == 1);
winfo(cp, &info, 0);
sigaddq(pp, NULL, &info, KM_NOSLEEP);
} else {
@@ -1804,6 +1863,15 @@ sigcld_repost()
sqp = kmem_zalloc(sizeof (sigqueue_t), KM_SLEEP);
mutex_enter(&pidlock);
+ if (PROC_IS_BRANDED(pp) && BROP(pp)->b_sigcld_repost != NULL) {
+ /*
+ * Allow the brand to inject synthetic SIGCLD signals.
+ */
+ if (BROP(pp)->b_sigcld_repost(pp, sqp) == 0) {
+ mutex_exit(&pidlock);
+ return;
+ }
+ }
for (cp = pp->p_child; cp; cp = cp->p_sibling) {
if (cp->p_pidflag & CLDPEND) {
post_sigcld(cp, sqp);
@@ -2115,7 +2183,7 @@ sigaddqa(proc_t *p, kthread_t *t, sigqueue_t *sigqp)
ASSERT(MUTEX_HELD(&p->p_lock));
ASSERT(sig >= 1 && sig < NSIG);
- if (sig_discardable(p, sig))
+ if (sig_discardable(p, t, sig))
siginfofree(sigqp);
else
sigaddqins(p, t, sigqp);
@@ -2141,7 +2209,7 @@ sigaddq(proc_t *p, kthread_t *t, k_siginfo_t *infop, int km_flags)
* blocking the signal (it *could* change it's mind while
* the signal is pending) then don't bother creating one.
*/
- if (!sig_discardable(p, sig) &&
+ if (!sig_discardable(p, t, sig) &&
(sigismember(&p->p_siginfo, sig) ||
(curproc->p_ct_process != p->p_ct_process) ||
(sig == SIGCLD && SI_FROMKERNEL(infop))) &&
generated by cgit v1.2.3 (git 2.39.1) at 2025-05-13 12:20:34 +0000