Simplify SIGCHLD handler setting
* strace.c (init): Set SIGCHLD to SIG_DFL earlier.
(startup_child): Do not bother restoring SIGCHLD handler.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/strace.c b/strace.c
index dda3404..f452254 100644
--- a/strace.c
+++ b/strace.c
@@ -873,21 +873,11 @@
if (!strace_vforked)
kill(pid, SIGSTOP);
} else {
- struct sigaction sv_sigchld;
- sigaction(SIGCHLD, NULL, &sv_sigchld);
- /*
- * Make sure it is not SIG_IGN, otherwise wait
- * will not block.
- */
- signal(SIGCHLD, SIG_DFL);
- /*
- * Wait for grandchild to attach to us.
- * It kills child after that, and wait() unblocks.
- */
alarm(3);
+ /* we depend on SIGCHLD set to SIG_DFL by init code */
+ /* if it happens to be SIG_IGN'ed, wait won't block */
wait(NULL);
alarm(0);
- sigaction(SIGCHLD, &sv_sigchld, NULL);
}
execv(pathname, argv);
@@ -1235,6 +1225,13 @@
progname = argv[0] ? argv[0] : "strace";
+ /* Make sure SIGCHLD has the default action so that waitpid
+ definitely works without losing track of children. The user
+ should not have given us a bogus state to inherit, but he might
+ have. Arguably we should detect SIG_IGN here and pass it on
+ to children, but probably noone really needs that. */
+ signal(SIGCHLD, SIG_DFL);
+
strace_tracer_pid = getpid();
os_release = get_os_release();
@@ -1502,14 +1499,6 @@
sigaction(SIGPIPE, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
}
- /* Make sure SIGCHLD has the default action so that waitpid
- definitely works without losing track of children. The user
- should not have given us a bogus state to inherit, but he might
- have. Arguably we should detect SIG_IGN here and pass it on
- to children, but probably noone really needs that. */
- sa.sa_handler = SIG_DFL;
- sigaction(SIGCHLD, &sa, NULL);
-
if (nprocs != 0 || daemonized_tracer)
startup_attach();