From bfd4b014074cdcc0e8b23c37ee678b37396e4968 Mon Sep 17 00:00:00 2001
From: Patrick Caulfield <pcaulfie@redhat.com>
Date: Wed, 6 Oct 2004 10:12:34 +0000
Subject: [PATCH] Revert the fork back to where it was as it seems to confuse
 pthreads. Instead, the parent now waits for the daemon to signal that it has
 completed successfully (or not) so it can return status to the user.

---
 WHATS_NEW             |  4 +-
 daemons/clvmd/clvmd.c | 87 ++++++++++++++++++++++++++++++++++---------
 2 files changed, 72 insertions(+), 19 deletions(-)

diff --git a/WHATS_NEW b/WHATS_NEW
index bcda5b1ec..a54d1929b 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,8 +1,8 @@
 Version 2.00.26 - 
 =====================================
-  Make clvmd fork later so it can return more error codes.
+  Improve clvmd error reporting during startup.
   Make clvmd cope with large gaps in node numbers IDs.
-  Make clvmd initialisation cope better with debugging output
+  Make clvmd initialisation cope better with debugging output.
   
 
 Version 2.00.25 - 29th September 2004
diff --git a/daemons/clvmd/clvmd.c b/daemons/clvmd/clvmd.c
index 81137a241..e0db11c52 100644
--- a/daemons/clvmd/clvmd.c
+++ b/daemons/clvmd/clvmd.c
@@ -82,6 +82,14 @@ static pthread_mutex_t lvm_thread_mutex;
 static pthread_cond_t lvm_thread_cond;
 static struct list lvm_cmd_head;
 static int quit = 0;
+static int child_pipe[2];
+
+/* Reasons the daemon failed initialisation */
+#define DFAIL_INIT       1
+#define DFAIL_LOCAL_SOCK 2
+#define DFAIL_CLUSTER_IF 3
+#define DFAIL_MALLOC     4
+#define SUCCESS          0
 
 /* Prototypes for code further down */
 static void sigusr2_handler(int sig);
@@ -129,6 +137,16 @@ static void usage(char *prog, FILE *file)
 	fprintf(file, "\n");
 }
 
+/* Called to signal the parent how well we got on during initialisation */
+static void child_init_signal(int status)
+{
+	write(child_pipe[1], &status, sizeof(status));
+	close(child_pipe[1]);
+	if (status)
+	        exit(status);
+}
+
+
 int main(int argc, char *argv[])
 {
 	int local_sock;
@@ -175,6 +193,11 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	/* Fork into the background (unless requested not to) */
+	if (!debug) {
+		be_daemon();
+	}
+
 	DEBUGLOG("CLVMD started\n");
 
 	/* Open the Unix socket we listen for commands on.
@@ -183,7 +206,7 @@ int main(int argc, char *argv[])
 	   but the cluster is not ready yet */
 	local_sock = open_local_sock();
 	if (local_sock < 0)
-		exit(2);
+		child_init_signal(DFAIL_LOCAL_SOCK);
 
 	/* Set up signal handlers, USR1 is for cluster change notifications (in cman)
 	   USR2 causes child threads to exit.
@@ -208,14 +231,8 @@ int main(int argc, char *argv[])
 	if (init_cluster()) {
 		DEBUGLOG("Can't initialise cluster interface\n");
 		log_error("Can't initialise cluster interface\n");
-		exit(5);
+		child_init_signal(DFAIL_CLUSTER_IF);
 	}
-
-	/* Fork into the background (unless requested not to) */
-	if (!debug) {
-		be_daemon();
-	}
-
 	DEBUGLOG("Cluster ready, doing some more initialisation\n");
 
 	/* Save our CSID */
@@ -229,10 +246,8 @@ int main(int argc, char *argv[])
 
 	/* Add the local socket to the list */
 	newfd = malloc(sizeof(struct local_client));
-	if (!newfd) {
-	        log_error("Can't allocate memory for socket structures. shutting down\n");
-		exit(2);
-	}
+	if (!newfd)
+	        child_init_signal(DFAIL_MALLOC);
 
 	newfd->fd = local_sock;
 	newfd->type = LOCAL_RENDEZVOUS;
@@ -254,6 +269,7 @@ int main(int argc, char *argv[])
 #endif
 
 	DEBUGLOG("clvmd ready for work\n");
+	child_init_signal(SUCCESS);
 
 	/* Do some work */
 	main_loop(local_sock, cmd_timeout);
@@ -584,26 +600,63 @@ static void main_loop(int local_sock, int cmd_timeout)
 	close(local_sock);
 }
 
-/* Fork into the background and detach from our parent process */
+/*
+ * Fork into the background and detach from our parent process.
+ * In the interests of user-friendliness we wait for the daemon
+ * to complete initialisation before returning its status
+ * the the user.
+ */
 static void be_daemon()
 {
-	pid_t pid;
+        pid_t pid;
+	int child_status;
 	int devnull = open("/dev/null", O_RDWR);
 	if (devnull == -1) {
 		perror("Can't open /dev/null");
 		exit(3);
 	}
 
+	pipe(child_pipe);
+
 	switch (pid = fork()) {
 	case -1:
 		perror("clvmd: can't fork");
 		exit(2);
 
-	case 0:		/* child */
+	case 0:		/* Child */
+	        close(child_pipe[0]);
 		break;
 
-	default:		/* Parent */
-		exit(0);
+	default:       /* Parent */
+		close(child_pipe[1]);
+		if (read(child_pipe[0], &child_status, sizeof(child_status)) !=
+		    sizeof(child_status)) {
+
+		        fprintf(stderr, "clvmd failed in initialisation\n");
+		        exit(DFAIL_INIT);
+		}
+		else {
+		        switch (child_status) {
+			case SUCCESS:
+			        break;
+			case DFAIL_INIT:
+			        fprintf(stderr, "clvmd failed in initialisation\n");
+				break;
+			case DFAIL_LOCAL_SOCK:
+			        fprintf(stderr, "clvmd could not create local socket\n");
+				break;
+			case DFAIL_CLUSTER_IF:
+			        fprintf(stderr, "clvmd could not connect to cluster\n");
+				break;
+			case DFAIL_MALLOC:
+			        fprintf(stderr, "clvmd failed, not enough memory\n");
+				break;
+			default:
+			        fprintf(stderr, "clvmd failed, error was %d\n", child_status);
+				break;
+			}
+			exit(child_status);
+		}
 	}
 
 	/* Detach ourself from the calling environment */
-- 
2.43.5