Simplify the abort() implementation.
I never understood the use of sigfillset() and SIG_SETMASK to unblock SIGABRT, so switch to sigemptyset() and SIG_UNBLOCK instead.
Similarly, just use signal() rather than sigaction() to set the default disposition.
Also remove the section sigprocmask() call, since there's no obvious reason to repeat that.
Also improve the comments.
Change-Id: I16c8b2557156a9787db792c074e77085fd46eda1
diff --git a/libc/bionic/abort.cpp b/libc/bionic/abort.cpp
index c8bba01..1b7a5e6 100644
--- a/libc/bionic/abort.cpp
+++ b/libc/bionic/abort.cpp
@@ -29,27 +29,27 @@
#include <signal.h>
#include <stdlib.h>
-#include <sys/syscall.h>
#include <unistd.h>
#include "private/bionic_inline_raise.h"
void abort() {
- // Don't block SIGABRT to give any signal handler a chance; we ignore
- // any errors -- X311J doesn't allow abort to return anyway.
- sigset64_t mask;
- sigfillset64(&mask);
- sigdelset64(&mask, SIGABRT);
+ // Since abort() must not return, there's no error checking in this function:
+ // there's no way to report an error anyway.
- sigprocmask64(SIG_SETMASK, &mask, nullptr);
+ // Unblock SIGABRT to give any signal handler a chance.
+ sigset64_t mask;
+ sigemptyset64(&mask);
+ sigaddset64(&mask, SIGABRT);
+ sigprocmask64(SIG_UNBLOCK, &mask, nullptr);
+
+ // Use inline_raise() to raise SIGABRT without adding an uninteresting
+ // stack frame that anyone investigating the crash would have to ignore.
inline_raise(SIGABRT);
- // If SIGABRT is ignored or it's caught and the handler returns,
- // remove the SIGABRT signal handler and raise SIGABRT again.
- struct sigaction64 sa = { .sa_handler = SIG_DFL, .sa_flags = SA_RESTART };
- sigaction64(SIGABRT, &sa, nullptr);
-
- sigprocmask64(SIG_SETMASK, &mask, nullptr);
+ // If that signal was ignored or was caught and the handler returned,
+ // remove the signal handler and raise SIGABRT again.
+ signal(SIGABRT, SIG_DFL);
inline_raise(SIGABRT);
// If we get this far, just exit.