daemon: Allow monitored daemon to dump core no more than once.

If the monitored daemon dumps core frequently, then this can quickly
exhaust the host's disk space.  This commit limits core dumps to at most
one per monitored session (typically, once per boot).

diff --git a/lib/daemon.c b/lib/daemon.c
index 081912b128c230c59550608059ea4cdc9a8b25a0..292be1465056831bfff8d68d9761c935e0b469a2 100644 (file)
--- a/lib/daemon.c
+++ b/lib/daemon.c
@@ -353,6 +353,18 @@ monitor_daemon(pid_t daemon_pid)
             free(s);
 
             if (should_restart(status)) {
+                if (WCOREDUMP(status)) {
+                    /* Disable further core dumps to save disk space. */
+                    struct rlimit r;
+
+                    r.rlim_cur = 0;
+                    r.rlim_max = 0;
+                    if (setrlimit(RLIMIT_CORE, &r) == -1) {
+                        VLOG_WARN("failed to disable core dumps: %s",
+                                  strerror(errno));
+                    }
+                }
+
                 VLOG_ERR("%s, restarting", status_msg);
                 daemon_pid = fork_and_wait_for_startup(&daemonize_fd);
                 if (!daemon_pid) {