MEDIUM: mworker: use the haproxy poll loop

In order to reorganize the code of the master worker, the mworker_wait()
function which was the main function was split. This function was
handling a wait() loop, but it does not need it anymore since the code
will use the poll loop of haproxy instead.

The function was split in several functions:

- mworker_catch_sigterm() which is a signal handler for SIGTERM ans
SIGUSR1 that sends the signals to the workers
- mworker_catch_sigchld() which is the code handling the leaving of a
child
- mworker_catch_sighup which basically call the mworker_restart()
function
- mworker_loop() which is the function calling the main poll loop in the
master

diff --git a/src/haproxy.c b/src/haproxy.c
index a0963a09a5952a2ea4a447d1f6274527f30fc374..d40316a6c1b60e7c38d5cd4de2f5cf5c54d9ffd1 100644 (file)
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -213,6 +213,8 @@ struct list global_listener_queue = LIST_HEAD_INIT(global_listener_queue);
 struct task *global_listener_queue_task;
 static struct task *manage_global_listener_queue(struct task *t, void *context, unsigned short state);
 
+static void *run_thread_poll_loop(void *data);
+
 /* bitfield of a few warnings to emit just once (WARN_*) */
 unsigned int warned = 0;
 
@@ -481,11 +483,6 @@ int current_child(int pid)
        return 0;
 }
 
-static void mworker_signalhandler(int signum)
-{
-       caught_signal = signum;
-}
-
 static void mworker_block_signals()
 {
        sigset_t set;
@@ -681,6 +678,8 @@ static void mworker_reload()
                next_argv[next_argc++] = NULL;
        }
 
+       deinit_pollers(); /* we don't want to leak the poller fd */
+
        ha_warning("Reexecuting Master process\n");
        execvp(next_argv[0], next_argv);
 
@@ -692,51 +691,41 @@ alloc_error:
        return;
 }
 
-
 /*
- * Wait for every children to exit
+ * When called, this function reexec haproxy with -sf followed by current
+ * children PIDs and possibily old children PIDs if they didn't leave yet.
  */
-
-static void mworker_wait()
+static void mworker_catch_sighup(struct sig_handler *sh)
 {
-       int exitpid = -1;
-       int status = 0;
+       mworker_reload();
+}
 
-restart_wait:
+static void mworker_catch_sigterm(struct sig_handler *sh)
+{
+       int sig = sh->arg;
 
 #if defined(USE_SYSTEMD)
-       if (global.tune.options & GTUNE_USE_SYSTEMD)
-               sd_notifyf(0, "READY=1\nMAINPID=%lu", (unsigned long)getpid());
+       if (global.tune.options & GTUNE_USE_SYSTEMD) {
+               sd_notify(0, "STOPPING=1");
+       }
 #endif
+       ha_warning("Exiting Master process...\n");
+       mworker_kill(sig);
+}
 
-       mworker_unblock_signals();
-
-       while (1) {
+/*
+ * Wait for every children to exit
+ */
 
-               while (((exitpid = wait(&status)) == -1) && errno == EINTR) {
-                       int sig = caught_signal;
-                       if (sig == SIGUSR2 || sig == SIGHUP) {
-                               mworker_reload();
-                               /* should reach there only if it fail */
-                               goto restart_wait;
-                       } else {
-#if defined(USE_SYSTEMD)
-                               if ((global.tune.options & GTUNE_USE_SYSTEMD) && (sig == SIGUSR1 || sig == SIGTERM)) {
-                                       sd_notify(0, "STOPPING=1");
-                               }
-#endif
-                               ha_warning("Exiting Master process...\n");
-                               mworker_kill(sig);
-                       }
-                       caught_signal = 0;
-               }
+static void mworker_catch_sigchld(struct sig_handler *sh)
+{
+       int exitpid = -1;
+       int status = 0;
 
-               if (exitpid == -1 && errno == ECHILD) {
-                       ha_warning("All workers exited. Exiting... (%d)\n", status);
-                       atexit_flag = 0;
-                       exit(status); /* parent must leave using the latest status code known */
-               }
+restart_wait:
 
+       exitpid = waitpid(-1, &status, WNOHANG);
+       if (exitpid > 0) {
                if (WIFEXITED(status))
                        status = WEXITSTATUS(status);
                else if (WIFSIGNALED(status))
@@ -762,9 +751,47 @@ restart_wait:
                                delete_oldpid(exitpid);
                        }
                }
+               /* do it again to check if it was the last worker */
+               goto restart_wait;
        }
+       /* Better rely on the system than on a list of process to check if it was the last one */
+       else if (exitpid == -1 && errno == ECHILD) {
+               ha_warning("All workers exited. Exiting... (%d)\n", status);
+               atexit_flag = 0;
+               exit(status); /* parent must leave using the latest status code known */
+       }
+
 }
 
+static void mworker_loop()
+{
+
+#if defined(USE_SYSTEMD)
+       if (global.tune.options & GTUNE_USE_SYSTEMD)
+               sd_notifyf(0, "READY=1\nMAINPID=%lu", (unsigned long)getpid());
+#endif
+
+       signal_register_fct(SIGTERM, mworker_catch_sigterm, SIGTERM);
+       signal_register_fct(SIGUSR1, mworker_catch_sigterm, SIGUSR1);
+       signal_register_fct(SIGINT, mworker_catch_sigterm, SIGINT);
+       signal_register_fct(SIGHUP, mworker_catch_sighup, SIGHUP);
+       signal_register_fct(SIGUSR2, mworker_catch_sighup, SIGUSR2);
+       signal_register_fct(SIGCHLD, mworker_catch_sigchld, SIGCHLD);
+
+       mworker_unblock_signals();
+       mworker_cleanlisteners();
+
+       global.nbthread = 1;
+       relative_pid = 1;
+       pid_bit = 1;
+
+       jobs++; /* this is the "master" job, we want to take care of the
+               signals even if there is no listener so the poll loop don't
+               leave */
+
+       fork_poller();
+       run_thread_poll_loop((int []){0});
+}
 
 /*
  * Reexec the process in failure mode, instead of exiting
@@ -1501,7 +1528,7 @@ static void init(int argc, char **argv)
        if ((global.mode & MODE_MWORKER) && (getenv("HAPROXY_MWORKER_WAIT_ONLY") != NULL)) {
 
                unsetenv("HAPROXY_MWORKER_WAIT_ONLY");
-               mworker_wait();
+               mworker_loop();
        }
 
        if ((global.mode & MODE_MWORKER) && (getenv("HAPROXY_MWORKER_REEXEC") != NULL)) {
@@ -2822,8 +2849,6 @@ int main(int argc, char **argv)
 
                if (proc == global.nbproc) {
                        if (global.mode & MODE_MWORKER) {
-                               mworker_cleanlisteners();
-                               deinit_pollers();
 
                                if ((!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE)) &&
                                        (global.mode & MODE_DAEMON)) {
@@ -2835,7 +2860,7 @@ int main(int argc, char **argv)
                                        global.mode |= MODE_QUIET; /* ensure that we won't say anything from now */
                                }
 
-                               mworker_wait();
+                               mworker_loop();
                                /* should never get there */
                                exit(EXIT_FAILURE);
                        }