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Merge pull request #688 from giuseppe/conmon-do-not-leave-zombies

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conmon: use waitpid to wait for terminated processes
This commit is contained in:
Mrunal Patel 2017-07-24 14:50:17 -07:00 committed by GitHub
commit 4cce851851
1 changed files with 63 additions and 3 deletions
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66
conmon/conmon.c
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@ -550,6 +550,45 @@ static bool read_stdio(int fd, stdpipe_t pipe, bool *eof)
}
}
static void on_sigchld(G_GNUC_UNUSED int signal)
{
raise (SIGUSR1);
}
static void check_child_processes(GHashTable *pid_to_handler)
{
void (*cb) (GPid, int, gpointer);
for (;;) {
int status;
pid_t pid = waitpid(-1, &status, WNOHANG);
if (pid < 0 && errno == EINTR)
continue;
if (pid < 0 && errno == ECHILD) {
g_main_loop_quit (main_loop);
return;
}
if (pid < 0)
pexit("Failed to read child process status");
if (pid == 0)
return;
/* If we got here, pid > 0, so we have a valid pid to check. */
cb = g_hash_table_lookup(pid_to_handler, &pid);
if (cb)
cb(pid, status, 0);
}
}
static gboolean on_sigusr1_cb(gpointer user_data)
{
GHashTable *pid_to_handler = (GHashTable *) user_data;
check_child_processes (pid_to_handler);
return G_SOURCE_CONTINUE;
}
static gboolean stdio_cb(int fd, GIOCondition condition, gpointer user_data)
{
stdpipe_t pipe = GPOINTER_TO_INT(user_data);
@ -1221,20 +1260,39 @@ int main(int argc, char *argv[])
close(slavefd_stdout);
close(slavefd_stderr);
/* Map pid to its handler. */
GHashTable *pid_to_handler = g_hash_table_new (g_int_hash, g_int_equal);
g_hash_table_insert (pid_to_handler, &create_pid, runtime_exit_cb);
/*
* Glib does not support SIGCHLD so use SIGUSR1 with the same semantic. We will
* catch SIGCHLD and raise(SIGUSR1) in the signal handler.
*/
g_unix_signal_add (SIGUSR1, on_sigusr1_cb, pid_to_handler);
if (signal(SIGCHLD, on_sigchld) == SIG_ERR)
pexit("Failed to set handler for SIGCHLD");
ninfo("about to waitpid: %d", create_pid);
if (csname != NULL) {
guint terminal_watch = g_unix_fd_add (console_socket_fd, G_IO_IN, terminal_accept_cb, csname);
g_child_watch_add (create_pid, runtime_exit_cb, NULL);
/* Process any SIGCHLD we may have missed before the signal handler was in place. */
check_child_processes (pid_to_handler);
g_main_loop_run (main_loop);
g_source_remove (terminal_watch);
} else {
int ret;
/* Wait for our create child to exit with the return code. */
if (waitpid(create_pid, &runtime_status, 0) < 0) {
do
ret = waitpid(create_pid, &runtime_status, 0);
while (ret < 0 && errno == EINTR);
if (ret < 0) {
int old_errno = errno;
kill(create_pid, SIGKILL);
errno = old_errno;
pexit("Failed to wait for `runtime %s`", opt_exec ? "exec" : "create");
}
}
if (!WIFEXITED(runtime_status) || WEXITSTATUS(runtime_status) != 0) {
@ -1266,6 +1324,8 @@ int main(int argc, char *argv[])
container_pid = atoi(contents);
ninfo("container PID: %d", container_pid);
g_hash_table_insert (pid_to_handler, &container_pid, container_exit_cb);
/* Setup endpoint for attach */
_cleanup_free_ char *attach_symlink_dir_path = NULL;
if (!opt_exec) {
@ -1294,7 +1354,7 @@ int main(int argc, char *argv[])
g_timeout_add_seconds (opt_timeout, timeout_cb, NULL);
}
g_child_watch_add (container_pid, container_exit_cb, NULL);
check_child_processes(pid_to_handler);
g_main_loop_run (main_loop);