fix async thread cancellation stack alignment

[musl] / src / signal / sigaction.c

diff --git a/src/signal/sigaction.c b/src/signal/sigaction.c
index ac9a3ac..2203471 100644 (file)
--- a/src/signal/sigaction.c
+++ b/src/signal/sigaction.c
@@ -4,13 +4,9 @@
 #include "syscall.h"
 #include "pthread_impl.h"
 #include "libc.h"
+#include "lock.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))];
 
@@ -19,10 +15,11 @@ void __get_handler_set(sigset_t *set)
        memcpy(set, handler_set, sizeof handler_set);
 }
 
+volatile int __eintr_valid_flag;
+
 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)),
@@ -41,14 +38,10 @@ int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigact
                                        SIGPT_SET, 0, _NSIG/8);
                                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);
+
+                       if (!(sa->sa_flags & SA_RESTART)) {
+                               a_store(&__eintr_valid_flag, 1);
+                       }
                }
                ksa.handler = sa->sa_handler;
                ksa.flags = sa->sa_flags | SA_RESTORER;
@@ -56,10 +49,6 @@ int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigact
                memcpy(&ksa.mask, &sa->sa_mask, _NSIG/8);
        }
        int r = __syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, _NSIG/8);
-       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;
@@ -70,11 +59,26 @@ int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigact
 
 int __sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
 {
+       unsigned long set[_NSIG/(8*sizeof(long))];
+
        if (sig-32U < 3 || sig-1U >= _NSIG-1) {
                errno = EINVAL;
                return -1;
        }
-       return __libc_sigaction(sig, sa, old);
+
+       /* Doing anything with the disposition of SIGABRT requires a lock,
+        * so that it cannot be changed while abort is terminating the
+        * process and so any change made by abort can't be observed. */
+       if (sig == SIGABRT) {
+               __block_all_sigs(&set);
+               LOCK(__abort_lock);
+       }
+       int r = __libc_sigaction(sig, sa, old);
+       if (sig == SIGABRT) {
+               UNLOCK(__abort_lock);
+               __restore_sigs(&set);
+       }
+       return r;
 }
 
 weak_alias(__sigaction, sigaction);