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authorMichael Roth <mdroth@linux.vnet.ibm.com>2011-12-07 21:48:07 -0600
committerAnthony Liguori <aliguori@us.ibm.com>2011-12-15 10:22:40 -0600
commit885660bd48efbe3742892e06de7a8898703e0bdc (patch)
tree53cc1f3b0d441246800120a4272f9b4482fa29ee
parentf603a687ff722e9df3e6e4730ca4e267aa2b124e (diff)
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 <jan.kiszka@siemens.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
-rw-r--r--net/tap.c6
1 files changed, 0 insertions, 6 deletions
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;