git daemon: avoid calling syslog() from a signal handler

Signal handlers should never call syslog(), as that can raise signals
of its own.

Instead, call the syslog() from the master process.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/daemon.c b/daemon.c
index 63cd12cd9c1909edbaab49aea066ff6fe03c3542..ce3a6f58f3c5c6bb88617510422c4053e0d545a2 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -694,23 +694,47 @@ static void kill_some_children(int signo, unsigned start, unsigned stop)
        }
 }
 
+static void check_dead_children(void)
+{
+       unsigned spawned, reaped, deleted;
+
+       spawned = children_spawned;
+       reaped = children_reaped;
+       deleted = children_deleted;
+
+       while (deleted < reaped) {
+               pid_t pid = dead_child[deleted % MAX_CHILDREN];
+               const char *dead = pid < 0 ? " (with error)" : "";
+
+               if (pid < 0)
+                       pid = -pid;
+
+               /* XXX: Custom logging, since we don't wanna getpid() */
+               if (verbose) {
+                       if (log_syslog)
+                               syslog(LOG_INFO, "[%d] Disconnected%s",
+                                               pid, dead);
+                       else
+                               fprintf(stderr, "[%d] Disconnected%s\n",
+                                               pid, dead);
+               }
+               remove_child(pid, deleted, spawned);
+               deleted++;
+       }
+       children_deleted = deleted;
+}
+
 static void check_max_connections(void)
 {
        for (;;) {
                int active;
-               unsigned spawned, reaped, deleted;
+               unsigned spawned, deleted;
+
+               check_dead_children();
 
                spawned = children_spawned;
-               reaped = children_reaped;
                deleted = children_deleted;
 
-               while (deleted < reaped) {
-                       pid_t pid = dead_child[deleted % MAX_CHILDREN];
-                       remove_child(pid, deleted, spawned);
-                       deleted++;
-               }
-               children_deleted = deleted;
-
                active = spawned - deleted;
                if (active <= max_connections)
                        break;
@@ -760,18 +784,10 @@ static void child_handler(int signo)
 
                if (pid > 0) {
                        unsigned reaped = children_reaped;
+                       if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
+                               pid = -pid;
                        dead_child[reaped % MAX_CHILDREN] = pid;
                        children_reaped = reaped + 1;
-                       /* XXX: Custom logging, since we don't wanna getpid() */
-                       if (verbose) {
-                               const char *dead = "";
-                               if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
-                                       dead = " (with error)";
-                               if (log_syslog)
-                                       syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
-                               else
-                                       fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
-                       }
                        continue;
                }
                break;
@@ -928,8 +944,18 @@ static int service_loop(int socknum, int *socklist)
 
        for (;;) {
                int i;
+               int timeout;
 
-               if (poll(pfd, socknum, -1) < 0) {
+               /*
+                * This 1-sec timeout could lead to idly looping but it is
+                * here so that children culled in child_handler() are reported
+                * without too much delay.  We could probably set up a pipe
+                * to ourselves that we poll, and write to the fd from child_handler()
+                * to wake us up (and consume it when the poll() returns...
+                */
+               timeout = (children_spawned != children_deleted) ? 1000 : -1;
+               i = poll(pfd, socknum, timeout);
+               if (i < 0) {
                        if (errno != EINTR) {
                                error("poll failed, resuming: %s",
                                      strerror(errno));
@@ -937,6 +963,10 @@ static int service_loop(int socknum, int *socklist)
                        }
                        continue;
                }
+               if (i == 0) {
+                       check_dead_children();
+                       continue;
+               }
 
                for (i = 0; i < socknum; i++) {
                        if (pfd[i].revents & POLLIN) {