+ * existing signal dispositions.
+@@ -69,33 +107,45 @@ __system(command)
+ (void)sigemptyset(&ign.sa_mask);
+ ign.sa_flags = 0;
+ (void)_sigaction(SIGINT, &ign, &intact);
++ if (intact.sa_handler != SIG_IGN) {
++ sigaddset(&defaultsig, SIGINT);
++ flags |= POSIX_SPAWN_SETSIGDEF;
++ }
+ (void)_sigaction(SIGQUIT, &ign, &quitact);
++ if (quitact.sa_handler != SIG_IGN) {
++ sigaddset(&defaultsig, SIGQUIT);
++ flags |= POSIX_SPAWN_SETSIGDEF;
++ }
+ (void)sigemptyset(&newsigblock);
+ (void)sigaddset(&newsigblock, SIGCHLD);
+ (void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
+- switch(pid = fork()) {
+- case -1: /* error */
+- break;
+- case 0: /* child */
+- /*
+- * Restore original signal dispositions and exec the command.
+- */
+- (void)_sigaction(SIGINT, &intact, NULL);
+- (void)_sigaction(SIGQUIT, &quitact, NULL);
+- (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+- execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
+- _exit(127);
+- default: /* parent */
++ (void)posix_spawnattr_setsigmask(&attr, &oldsigblock);
++ if (flags & POSIX_SPAWN_SETSIGDEF) {
++ (void)posix_spawnattr_setsigdefault(&attr, &defaultsig);
++ }
++ (void)posix_spawnattr_setflags(&attr, flags);
++
++ err = posix_spawn(&pid, _PATH_BSHELL, NULL, &attr, (char *const *)argv, environ);
++ (void)posix_spawnattr_destroy(&attr);
++ if (err == 0) {
+ savedpid = pid;
+ do {
+ pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0);
+ } while (pid == -1 && errno == EINTR);
+- break;
++ if (pid == -1) pstat = -1;
++ } else if (err == ENOMEM || err == EAGAIN) { /* as if fork failed */
++ pstat = -1;
++ } else {
++ pstat = W_EXITCODE(127, 0); /* couldn't exec shell */
+ }
++
+ (void)_sigaction(SIGINT, &intact, NULL);
+ (void)_sigaction(SIGQUIT, &quitact, NULL);
+ (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+- return(pid == -1 ? -1 : pstat);
++#if __DARWIN_UNIX03
++ pthread_mutex_unlock(&__systemfn_mutex);
++#endif /* __DARWIN_UNIX03 */
++ return(pstat);
+ }
+
+ __weak_reference(__system, system);