about summary refs log tree commit diff
path: root/src/signal
diff options
context:
space:
mode:
Diffstat (limited to 'src/signal')
-rw-r--r--src/signal/sigaction.c25
1 files changed, 21 insertions, 4 deletions
diff --git a/src/signal/sigaction.c b/src/signal/sigaction.c
index 6eca06f1..79989500 100644
--- a/src/signal/sigaction.c
+++ b/src/signal/sigaction.c
@@ -6,6 +6,11 @@
 #include "libc.h"
 #include "ksigaction.h"
 
+volatile int dummy_lock[1] = { 0 };
+
+__attribute__((__visibility__("hidden")))
+weak_alias(dummy_lock, __abort_lock);
+
 static int unmask_done;
 static unsigned long handler_set[_NSIG/(8*sizeof(long))];
 
@@ -17,6 +22,7 @@ void __get_handler_set(sigset_t *set)
 int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
 {
 	struct k_sigaction ksa, ksa_old;
+	unsigned long set[_NSIG/(8*sizeof(long))];
 	if (sa) {
 		if ((uintptr_t)sa->sa_handler > 1UL) {
 			a_or_l(handler_set+(sig-1)/(8*sizeof(long)),
@@ -36,19 +42,30 @@ int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigact
 				unmask_done = 1;
 			}
 		}
+		/* Changing the disposition of SIGABRT to anything but
+		 * SIG_DFL requires a lock, so that it cannot be changed
+		 * while abort is terminating the process after simply
+		 * calling raise(SIGABRT) failed to do so. */
+		if (sa->sa_handler != SIG_DFL && sig == SIGABRT) {
+			__block_all_sigs(&set);
+			LOCK(__abort_lock);
+		}
 		ksa.handler = sa->sa_handler;
 		ksa.flags = sa->sa_flags | SA_RESTORER;
 		ksa.restorer = (sa->sa_flags & SA_SIGINFO) ? __restore_rt : __restore;
 		memcpy(&ksa.mask, &sa->sa_mask, sizeof ksa.mask);
 	}
-	if (syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, sizeof ksa.mask))
-		return -1;
-	if (old) {
+	int r = __syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, sizeof ksa.mask);
+	if (sig == SIGABRT && sa && sa->sa_handler != SIG_DFL) {
+		UNLOCK(__abort_lock);
+		__restore_sigs(&set);
+	}
+	if (old && !r) {
 		old->sa_handler = ksa_old.handler;
 		old->sa_flags = ksa_old.flags;
 		memcpy(&old->sa_mask, &ksa_old.mask, sizeof ksa_old.mask);
 	}
-	return 0;
+	return __syscall_ret(r);
 }
 
 int __sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)