redesign sigsetjmp so that signal mask is restored after longjmp

[musl] / src / signal / sigaction.c

diff --git a/src/signal/sigaction.c b/src/signal/sigaction.c
index 2331dc9..d5f4774 100644 (file)
--- a/src/signal/sigaction.c
+++ b/src/signal/sigaction.c
@@ -1,6 +1,6 @@
-#include <stdlib.h>
 #include <signal.h>
 #include <errno.h>
+#include <string.h>
 #include "syscall.h"
 #include "pthread_impl.h"
 #include "libc.h"
@@ -8,25 +8,51 @@
 
 void __restore(), __restore_rt();
 
-static pthread_t dummy(void) { return 0; }
-weak_alias(dummy, __pthread_self_def);
+static int unmask_done;
+static unsigned long handler_set[_NSIG/(8*sizeof(long))];
+
+void __get_handler_set(sigset_t *set)
+{
+       memcpy(set, handler_set, sizeof handler_set);
+}
 
 int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
 {
-       struct k_sigaction ksa;
+       struct k_sigaction ksa, ksa_old;
+       if (sig >= (unsigned)_NSIG) {
+               errno = EINVAL;
+               return -1;
+       }
        if (sa) {
+               if ((uintptr_t)sa->sa_handler > 1UL) {
+                       a_or_l(handler_set+(sig-1)/(8*sizeof(long)),
+                               1UL<<(sig-1)%(8*sizeof(long)));
+
+                       /* If pthread_create has not yet been called,
+                        * implementation-internal signals might not
+                        * yet have been unblocked. They must be
+                        * unblocked before any signal handler is
+                        * installed, so that an application cannot
+                        * receive an illegal sigset_t (with them
+                        * blocked) as part of the ucontext_t passed
+                        * to the signal handler. */
+                       if (!libc.threaded && !unmask_done) {
+                               __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
+                                       SIGPT_SET, 0, _NSIG/8);
+                               unmask_done = 1;
+                       }
+               }
                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);
        }
-       __pthread_self_def();
-       if (syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa:0, sizeof ksa.mask))
+       if (syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, sizeof ksa.mask))
                return -1;
        if (old) {
-               old->sa_handler = ksa.handler;
-               old->sa_flags = ksa.flags;
-               memcpy(&old->sa_mask, &ksa.mask, sizeof ksa.mask);
+               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;
 }