Improve handling of unexpected 'status' in process_status_msg().

[sliver-openvswitch.git] / lib / daemon.c

diff --git a/lib/daemon.c b/lib/daemon.c
index c0b42bc..3b766b5 100644 (file)
--- a/lib/daemon.c
+++ b/lib/daemon.c
@@ -39,6 +39,7 @@
 #include <string.h>
 #include <unistd.h>
 #include "fatal-signal.h"
+#include "dirs.h"
 #include "util.h"
 
 #define THIS_MODULE VLM_daemon
@@ -58,9 +59,9 @@ static bool force;
 char *
 make_pidfile_name(const char *name) 
 {
-    return (!name ? xasprintf("%s/%s.pid", RUNDIR, program_name)
+    return (!name ? xasprintf("%s/%s.pid", ofp_rundir, program_name)
             : *name == '/' ? xstrdup(name)
-            : xasprintf("%s/%s", RUNDIR, name));
+            : xasprintf("%s/%s", ofp_rundir, name));
 }
 
 /* Sets up a following call to daemonize() to create a pidfile named 'name'.
@@ -212,7 +213,9 @@ daemonize(void)
             /* Parent process: wait for child to create pidfile, then exit. */
             close(fds[1]);
             fatal_signal_fork();
-            read(fds[0], &c, 1);
+            if (read(fds[0], &c, 1) != 1) {
+                ofp_fatal(errno, "daemon child failed to signal startup");
+            }
             exit(0);
 
         case 0:
@@ -235,3 +238,73 @@ daemonize(void)
     }
 }
 
+void
+daemon_usage(void)
+{
+    printf(
+        "\nDaemon options:\n"
+        "  -D, --detach            run in background as daemon\n"
+        "  -P, --pidfile[=FILE]    create pidfile (default: %s/%s.pid)\n"
+        "  -f, --force             with -P, start even if already running\n",
+        ofp_rundir, program_name);
+}
+
+/* Opens and reads a PID from 'pidfile'.  Returns the nonnegative PID if
+ * successful, otherwise a negative errno value. */
+pid_t
+read_pidfile(const char *pidfile)
+{
+    char line[128];
+    struct flock lck;
+    FILE *file;
+    int error;
+
+    file = fopen(pidfile, "r");
+    if (!file) {
+        error = errno;
+        VLOG_WARN("%s: open: %s", pidfile, strerror(error));
+        goto error;
+    }
+
+    lck.l_type = F_WRLCK;
+    lck.l_whence = SEEK_SET;
+    lck.l_start = 0;
+    lck.l_len = 0;
+    if (fcntl(fileno(file), F_GETLK, &lck)) {
+        error = errno;
+        VLOG_WARN("%s: fcntl: %s", pidfile, strerror(error));
+        goto error;
+    }
+    if (lck.l_type == F_UNLCK) {
+        error = ESRCH;
+        VLOG_WARN("%s: pid file is not locked", pidfile);
+        goto error;
+    }
+
+    if (!fgets(line, sizeof line, file)) {
+        if (ferror(file)) {
+            error = errno;
+            VLOG_WARN("%s: read: %s", pidfile, strerror(error));
+        } else {
+            error = ESRCH;
+            VLOG_WARN("%s: read: unexpected end of file", pidfile);
+        }
+        goto error;
+    }
+
+    if (lck.l_pid != strtoul(line, NULL, 10)) {
+        error = ESRCH;
+        VLOG_WARN("l_pid (%ld) != %s pid (%s)",
+                   (long int) lck.l_pid, pidfile, line);
+        goto error;
+    }
+
+    fclose(file);
+    return lck.l_pid;
+
+error:
+    if (file) {
+        fclose(file);
+    }
+    return -error;
+}