From 885660bd48efbe3742892e06de7a8898703e0bdc Mon Sep 17 00:00:00 2001 From: Michael Roth Date: Wed, 7 Dec 2011 21:48:07 -0600 Subject: network scripts: don't block SIGCHLD before forking This patch fixes a bug where child processes of launch_script() can misbehave due to SIGCHLD being blocked. In the case of `sudo`, this causes a permanent hang. Previously a SIGCHLD handler was added to reap fork_exec()'d zombie processes by calling waitpid(-1, ...). This required other fork()/waitpid() callers to temporarilly block SIGCHILD to avoid having the final wait status being intercepted by the SIGCHLD handler: 7c3370d4fe3fa6cda8655f109e4659afc8ca4269 Since then, the qemu_add_child_watch() interface was added to allow registration of such processes and reap only from that specific set of PIDs: 4d54ec7898bd951007cb6122d5315584bd41d0c4 As a result, we can now avoid blocking SIGCHLD in launch_script(), so drop that behavior. Reviewed-by: Jan Kiszka Reviewed-by: Paolo Bonzini Signed-off-by: Michael Roth Signed-off-by: Anthony Liguori --- net/tap.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'net/tap.c') diff --git a/net/tap.c b/net/tap.c index 1f26dc9992..6c27a9427f 100644 --- a/net/tap.c +++ b/net/tap.c @@ -346,15 +346,10 @@ static TAPState *net_tap_fd_init(VLANState *vlan, static int launch_script(const char *setup_script, const char *ifname, int fd) { - sigset_t oldmask, mask; int pid, status; char *args[3]; char **parg; - sigemptyset(&mask); - sigaddset(&mask, SIGCHLD); - sigprocmask(SIG_BLOCK, &mask, &oldmask); - /* try to launch network script */ pid = fork(); if (pid == 0) { @@ -378,7 +373,6 @@ static int launch_script(const char *setup_script, const char *ifname, int fd) while (waitpid(pid, &status, 0) != pid) { /* loop */ } - sigprocmask(SIG_SETMASK, &oldmask, NULL); if (WIFEXITED(status) && WEXITSTATUS(status) == 0) { return 0; -- cgit v1.2.1