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Simplify SIGCHLD handler setting

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* 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>
This commit is contained in:
Denys Vlasenko 2012-03-15 17:27:49 +01:00
parent 2c4fb905fe
commit a509054aee
1 changed files with 9 additions and 20 deletions
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29
strace.c
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@ -873,21 +873,11 @@ startup_child(char **argv)
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 @@ init(int argc, char *argv[])
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 @@ init(int argc, char *argv[])
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();