Replace client_should_run with a 5 state enum to avoid races if multiple

CLI sources yell at the same time.

git-svn-id: svn+ssh://projects.linpro.no/svn/varnish/trunk@674 d4fa192b-c00b-0410-8231-f00ffab90ce4

diff --git a/varnish-cache/bin/varnishd/mgt_child.c b/varnish-cache/bin/varnishd/mgt_child.c
index ac74847d2bc3a554bd911849ce910e7498691707..94b8fef9ed2f6603dc624ad064b83de67af1874d 100644 (file)
--- a/varnish-cache/bin/varnishd/mgt_child.c
+++ b/varnish-cache/bin/varnishd/mgt_child.c
@@ -29,7 +29,13 @@ pid_t                mgt_pid;
 pid_t          child_pid = -1;
 
 static int             child_fds[2];
-static unsigned        child_should_run;
+static enum {
+       CH_STOPPED = 0,
+       CH_STARTING = 1,
+       CH_RUNNING = 2,
+       CH_STOPPING = 3,
+       CH_DIED = 4
+}                      child_state = CH_STOPPED;
 
 struct evbase          *mgt_evb;
 struct ev              *ev_poker;
@@ -54,7 +60,7 @@ child_listener(struct ev *e, int what)
                return (1);
        }
        buf[i] = '\0';
-       printf("Child said: <<%s>>\n", buf);
+       printf("Child said (%d, %d): <<%s>>\n", child_state, child_pid, buf);
        return (0);
 }
 
@@ -66,7 +72,7 @@ child_poker(struct ev *e, int what)
 
        (void)e;
        (void)what;
-       if (!child_should_run)
+       if (child_state != CH_RUNNING)
                return (1);
        if (child_pid > 0 && mgt_cli_askchild(NULL, NULL, "ping\n"))
                kill(child_pid, SIGKILL);
@@ -82,10 +88,10 @@ start_child(void)
        char *p;
        struct ev *e;
 
-       if (child_pid >= 0)
+       if (child_state != CH_STOPPED && child_state != CH_DIED)
                return;
 
-       child_should_run = 1;
+       child_state = CH_STARTING;
 
        AZ(pipe(&heritage.fds[0]));
        AZ(pipe(&heritage.fds[2]));
@@ -147,6 +153,7 @@ start_child(void)
                free(p);
                exit (2);
        }
+       child_state = CH_RUNNING;
 }
 
 /*--------------------------------------------------------------------*/
@@ -155,15 +162,15 @@ static void
 stop_child(void)
 {
 
-       if (child_pid < 0)
+       if (child_state != CH_RUNNING)
                return;
 
+       child_state = CH_STOPPING;
+
        if (ev_poker != NULL)
                ev_del(mgt_evb, ev_poker);
        ev_poker = NULL;
 
-       child_should_run = 0;
-
        printf("Clean child\n");
        mgt_cli_stop_child();
 
@@ -173,7 +180,7 @@ stop_child(void)
        AZ(close(heritage.fds[3]));
        heritage.fds[3] = -1;
 
-       printf("Child stopped\n");
+       printf("Child stopping\n");
 }
 
 /*--------------------------------------------------------------------*/
@@ -200,7 +207,8 @@ mgt_sigchld(struct ev *e, int what)
        printf("Cache child died pid=%d status=0x%x\n", r, status);
        child_pid = -1;
 
-       if (child_should_run) {
+       if (child_state == CH_RUNNING) {
+               child_state = CH_DIED;
                printf("Clean child\n");
                mgt_cli_stop_child();
 
@@ -219,8 +227,10 @@ mgt_sigchld(struct ev *e, int what)
        child_fds[0] = -1;
        printf("Child cleaned\n");
 
-       if (child_should_run)
+       if (child_state == CH_DIED)
                start_child();
+       else if (child_state == CH_STOPPING)
+               child_state = CH_STOPPED;
        return (0);
 }
 
@@ -278,6 +288,7 @@ mgt_run(int dflag)
 
        sac.sa_handler = SIG_IGN;
        sac.sa_flags = SA_RESTART;
+
        AZ(sigaction(SIGPIPE, &sac, NULL));
        AZ(sigaction(SIGHUP, &sac, NULL));