From 66e9a0322ba241a375ddb145ff468454b2baf715 Mon Sep 17 00:00:00 2001
From: deva <deva>
Date: Wed, 7 Jul 2010 12:25:13 +0000
Subject: Refuse to start if pid file already exists, or cannot be written.
 Remove pid file when shutting down (if possible).

---
 server/src/daemon.cc | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/server/src/daemon.cc b/server/src/daemon.cc
index 9de3807..aabaa2f 100644
--- a/server/src/daemon.cc
+++ b/server/src/daemon.cc
@@ -103,8 +103,19 @@ int Daemon::run(const char *user, const char* group, bool detach,
 
   umask(0);
 
+  if(pidfile != "" ) {
+    FILE *fp = fopen(pidfile.c_str(), "r");
+    if(fp != NULL) {
+      fclose(fp);
+      fprintf(stderr, "Could not write pid file \"%s\""
+              " - file already exists.\n",
+              pidfile.c_str());
+      return -1;
+    }
+  }
+
   if(detach) {
-    if( daemon(0, 0) == -1) { 
+    if(daemon(0, 0) == -1) { 
       perror("");
       return -1; 
     }
@@ -112,10 +123,12 @@ int Daemon::run(const char *user, const char* group, bool detach,
 
   if(pidfile != "" ) {
     pid_t pid = getpid();
+
     FILE *fp = fopen(pidfile.c_str(), "w");
-    if(errno) {
+    if(fp == NULL) {
       fprintf(stderr, "Could not write pid file \"%s\"", pidfile.c_str());
       perror("");
+      return -1;
     } else {
       fprintf(fp, "%lu", (unsigned long int)pid);
       fclose(fp);
@@ -151,5 +164,11 @@ int Daemon::run(const char *user, const char* group, bool detach,
   // Don't disable Ctrl+c when running in foreground.
   //if(detach) signal (SIGINT, SIG_IGN);
 
-  return daemon_main();
+  int ret = daemon_main();
+
+  if(pidfile != "") {
+    unlink(pidfile.c_str());
+  }
+
+  return ret;
 }
-- 
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