MEDIUM: Improve signal handling in systemd wrapper.
Move all code out of the signal handlers, since this is potentially
dangerous. To make sure the signal handlers behave as expected, use
sigaction() instead of signal(). That also obsoletes messing with
the signal mask after restart.
Signed-off-by: Conrad Hoffmann <conrad@soundcloud.com>
(cherry picked from commit 5b5ea9c93384da49eea0f67ebed0966d4167b17a)
diff --git a/src/haproxy-systemd-wrapper.c b/src/haproxy-systemd-wrapper.c
index 529b213..90a94ce 100644
--- a/src/haproxy-systemd-wrapper.c
+++ b/src/haproxy-systemd-wrapper.c
@@ -22,6 +22,8 @@
#define SD_DEBUG "<7>"
#define SD_NOTICE "<5>"
+static volatile sig_atomic_t caught_signal;
+
static char *pid_file = "/run/haproxy.pid";
static int wrapper_argc;
static char **wrapper_argv;
@@ -103,7 +105,12 @@
return read;
}
+static void signal_handler(int signum)
+{
+ caught_signal = signum;
+}
+
-static void sigusr2_handler(int signum __attribute__((unused)))
+static void do_restart(void)
{
setenv(REEXEC_FLAG, "1", 1);
fprintf(stderr, SD_NOTICE "haproxy-systemd-wrapper: re-executing\n");
@@ -111,7 +118,7 @@
execv(wrapper_argv[0], wrapper_argv);
}
-static void sigint_handler(int signum __attribute__((unused)))
+static void do_shutdown(void)
{
int i, pid;
char **pid_strv = NULL;
@@ -147,25 +154,21 @@
--argc; ++argv;
init(argc, argv);
- signal(SIGINT, &sigint_handler);
- signal(SIGUSR2, &sigusr2_handler);
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(struct sigaction));
+ sa.sa_handler = &signal_handler;
+ sigaction(SIGUSR2, &sa, NULL);
+ sigaction(SIGINT, &sa, NULL);
if (getenv(REEXEC_FLAG) != NULL) {
/* We are being re-executed: restart HAProxy gracefully */
int i;
char **pid_strv = NULL;
int nb_pid = read_pids(&pid_strv);
- sigset_t sigs;
unsetenv(REEXEC_FLAG);
spawn_haproxy(pid_strv, nb_pid);
- /* Unblock SIGUSR2 which was blocked by the signal handler
- * before re-exec */
- sigprocmask(SIG_BLOCK, NULL, &sigs);
- sigdelset(&sigs, SIGUSR2);
- sigprocmask(SIG_SETMASK, &sigs, NULL);
-
for (i = 0; i < nb_pid; ++i)
free(pid_strv[i]);
free(pid_strv);
@@ -176,8 +179,16 @@
}
status = -1;
- while (-1 != wait(&status) || errno == EINTR)
- ;
+ while (-1 != wait(&status) || errno == EINTR) {
+ if (caught_signal == SIGUSR2) {
+ caught_signal = 0;
+ do_restart();
+ }
+ else if (caught_signal == SIGINT) {
+ caught_signal = 0;
+ do_shutdown();
+ }
+ }
fprintf(stderr, SD_NOTICE "haproxy-systemd-wrapper: exit, haproxy RC=%d\n",
status);