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- From 7a7eada6f4ecfc54325a18cf20c3035994a901c4 Mon Sep 17 00:00:00 2001
- From: Willy Tarreau <w@1wt.eu>
- Date: Tue, 25 Oct 2016 16:49:31 +0200
- Subject: [PATCH 13/26] BUG/MINOR: systemd: always restore signals before
- execve()
-
- Since signals are inherited, we must restore them before calling execve()
- and intercept them again after a failed execve(). In order to cleanly deal
- with the SIGUSR2/SIGHUP loops where we re-exec the wrapper, we ignore these
- two signals during a re-exec, and restore them to defaults when spawning
- haproxy.
-
- This should be backported to 1.6 and 1.5.
- (cherry picked from commit 4351ea61fbddf88c960179d60b0e0f1b090f0b70)
- ---
- src/haproxy-systemd-wrapper.c | 49 ++++++++++++++++++++++++++++++++++++-------
- 1 file changed, 41 insertions(+), 8 deletions(-)
-
- diff --git a/src/haproxy-systemd-wrapper.c b/src/haproxy-systemd-wrapper.c
- index a78e75b..84d2e17 100644
- --- a/src/haproxy-systemd-wrapper.c
- +++ b/src/haproxy-systemd-wrapper.c
- @@ -28,6 +28,11 @@ static char *pid_file = "/run/haproxy.pid";
- static int wrapper_argc;
- static char **wrapper_argv;
-
- +static void setup_signal_handler();
- +static void pause_signal_handler();
- +static void reset_signal_handler();
- +
- +
- /* returns the path to the haproxy binary into <buffer>, whose size indicated
- * in <buffer_size> must be at least 1 byte long.
- */
- @@ -76,6 +81,8 @@ static void spawn_haproxy(char **pid_strv, int nb_pid)
- char **argv = calloc(4 + main_argc + nb_pid + 1, sizeof(char *));
- int i;
- int argno = 0;
- +
- + reset_signal_handler();
- locate_haproxy(haproxy_bin, 512);
- argv[argno++] = haproxy_bin;
- for (i = 0; i < main_argc; ++i)
- @@ -127,6 +134,34 @@ static void signal_handler(int signum)
- caught_signal = signum;
- }
-
- +static void setup_signal_handler()
- +{
- + struct sigaction sa;
- +
- + memset(&sa, 0, sizeof(struct sigaction));
- + sa.sa_handler = &signal_handler;
- + sigaction(SIGUSR2, &sa, NULL);
- + sigaction(SIGHUP, &sa, NULL);
- + sigaction(SIGINT, &sa, NULL);
- + sigaction(SIGTERM, &sa, NULL);
- +}
- +
- +static void pause_signal_handler()
- +{
- + signal(SIGUSR2, SIG_IGN);
- + signal(SIGHUP, SIG_IGN);
- + signal(SIGINT, SIG_DFL);
- + signal(SIGTERM, SIG_DFL);
- +}
- +
- +static void reset_signal_handler()
- +{
- + signal(SIGUSR2, SIG_DFL);
- + signal(SIGHUP, SIG_DFL);
- + signal(SIGINT, SIG_DFL);
- + signal(SIGTERM, SIG_DFL);
- +}
- +
- /* handles SIGUSR2 and SIGHUP only */
- static void do_restart(int sig)
- {
- @@ -134,7 +169,11 @@ static void do_restart(int sig)
- fprintf(stderr, SD_NOTICE "haproxy-systemd-wrapper: re-executing on %s.\n",
- sig == SIGUSR2 ? "SIGUSR2" : "SIGHUP");
-
- + /* don't let the other process take one of those signals by accident */
- + pause_signal_handler();
- execv(wrapper_argv[0], wrapper_argv);
- + /* failed, let's reinstall the signal handler and continue */
- + setup_signal_handler();
- }
-
- /* handles SIGTERM and SIGINT only */
- @@ -168,7 +207,8 @@ static void init(int argc, char **argv)
- int main(int argc, char **argv)
- {
- int status;
- - struct sigaction sa;
- +
- + setup_signal_handler();
-
- wrapper_argc = argc;
- wrapper_argv = argv;
- @@ -176,13 +216,6 @@ int main(int argc, char **argv)
- --argc; ++argv;
- init(argc, argv);
-
- - memset(&sa, 0, sizeof(struct sigaction));
- - sa.sa_handler = &signal_handler;
- - sigaction(SIGUSR2, &sa, NULL);
- - sigaction(SIGHUP, &sa, NULL);
- - sigaction(SIGINT, &sa, NULL);
- - sigaction(SIGTERM, &sa, NULL);
- -
- if (getenv(REEXEC_FLAG) != NULL) {
- /* We are being re-executed: restart HAProxy gracefully */
- int i;
- --
- 2.7.3
-
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