When built with an old thread implementation (or for a sparc target), the implementation of the system() function doesn't conform to its specification. Namely, it resets the SIGCHLD handler to its default instead of blocking the signal, which may result in "lost" signals if a custom handler was installed. Replace this by appropriate calls to sigprocmask().
Signed-off-by: Richard Braun <[email protected]> --- libc/stdlib/system.c | 34 ++++++++++++++++++++++------------ 1 files changed, 22 insertions(+), 12 deletions(-) diff --git a/libc/stdlib/system.c b/libc/stdlib/system.c index a0ff726..7fd9568 100644 --- a/libc/stdlib/system.c +++ b/libc/stdlib/system.c @@ -32,26 +32,33 @@ extern __typeof(system) __libc_system; int __libc_system(const char *command) { - int wait_val, pid; - __sighandler_t save_quit, save_int, save_chld; + int ret_val, pid; + __sighandler_t save_quit, save_int; + sigset_t smask, omask; if (command == 0) return 1; save_quit = signal(SIGQUIT, SIG_IGN); save_int = signal(SIGINT, SIG_IGN); - save_chld = signal(SIGCHLD, SIG_DFL); + + sigemptyset(&smask); + sigaddset(&smask, SIGCHLD); + + if (sigprocmask(SIG_BLOCK, &smask, &omask) != 0) { + ret_val = -1; + goto error_block; + } if ((pid = vfork()) < 0) { - signal(SIGQUIT, save_quit); - signal(SIGINT, save_int); - signal(SIGCHLD, save_chld); - return -1; + ret_val = -1; + goto error_vfork; } + if (pid == 0) { signal(SIGQUIT, SIG_DFL); signal(SIGINT, SIG_DFL); - signal(SIGCHLD, SIG_DFL); + sigprocmask(SIG_SETMASK, &omask, NULL); execl("/bin/sh", "sh", "-c", command, (char *) 0); _exit(127); @@ -64,13 +71,16 @@ int __libc_system(const char *command) __printf("Waiting for child %d\n", pid); #endif - if (wait4(pid, &wait_val, 0, 0) == -1) - wait_val = -1; + if (wait4(pid, &ret_val, 0, 0) == -1) + ret_val = -1; +error_vfork: + if (sigprocmask(SIG_SETMASK, &omask, NULL) != 0) + ret_val = -1; +error_block: signal(SIGQUIT, save_quit); signal(SIGINT, save_int); - signal(SIGCHLD, save_chld); - return wait_val; + return ret_val; } #else /* We have to and actually can handle cancelable system(). The big -- 1.7.2.5 _______________________________________________ uClibc mailing list [email protected] http://lists.busybox.net/mailman/listinfo/uclibc
