[Iscsitarget-devel] [patch] opening multiple ietd instances corrupts kernel nl_socket state

[Ross S. W. W. <RW...@me...>]

The PID file test wasn't performed early enough which allowed a
second ietd instance starting up to mess up the netlink socket
state for the running ietd.

With this patch the new order of ietd startup:

- process options
- initialize log (if daemon)
- disassociate tty (if daemon)
- create PID file, prevents second instance from starting
- create IPC socket, if PID was removed this will also prevent
  a second instance from starting
- open control device
- test version
- open netlink socket for ietd<->kernel messaging
- read config
- set effective GID/UID
- enter event loop

Signed-off-by: Ross Walker

Index: usr/ietd.c
===================================================================
--- usr/ietd.c	(revision 339)
+++ usr/ietd.c	(working copy)
@@ -434,11 +434,11 @@ void event_loop(int timeout)
 int main(int argc, char **argv)
 {
 	int ch, longindex, timeout = -1;
-	char *config = NULL;
+	char *config = NULL, pid_buf[64];
 	uid_t uid = 0;
 	gid_t gid = 0;
 	char *isns = NULL;
-	int isns_ac = 0;
+	int isns_ac = 0, pid_fd;
 
 	/* otherwise we would die in some later write() during the event_loop
 	 * instead of getting EPIPE! */
@@ -480,81 +480,86 @@ int main(int argc, char **argv)
 		}
 	}
 
-	log_init();
+	if (log_daemon) {
+		pid_t pid;
 
-	if ((nl_fd = nl_open()) < 0) {
-		log_error("unable to open netlink fd: %m");
-		exit(-1);
-	};
+		log_init();
 
-	if ((ctrl_fd = ki->ctldev_open()) < 0) {
-		log_error("unable to open ctldev fd: %m");
+		pid = fork();
+		if (pid < 0) {
+			log_error("error starting daemon: %m");
+			exit(-1);
+		} else if (pid)
+			exit(0);
+
+		close(0);
+		open("/dev/null", O_RDWR);
+		dup2(0, 1);
+		dup2(0, 2);
+
+		setsid();
+	}
+
+	pid_fd = open("/var/run/ietd.pid", O_WRONLY|O_CREAT, 0644);
+	if (pid_fd < 0) {
+		log_error("unable to create pid file: %m");
 		exit(-1);
 	}
 
-	if ((ipc_fd = ietadm_request_listen()) < 0) {
-		log_error("unable to open ipc fd: %m");
+	if (chdir("/") < 0) {
+		log_error("failed to set working dir to /: %m");
 		exit(-1);
 	}
 
-	if (!check_version()) {
-		log_error("kernel module version mismatch!");
+	if (lockf(pid_fd, F_TLOCK, 0) < 0) {
+		log_error("unable to lock pid file: %m");
 		exit(-1);
 	}
 
-	if (log_daemon) {
-		char buf[64];
-		pid_t pid;
-		int fd;
+	if (ftruncate(pid_fd, 0) < 0) {
+		log_error("failed to ftruncate the PID file: %m");
+		exit(-1);
+	}
 
-		fd = open("/var/run/iscsi_trgt.pid", O_WRONLY|O_CREAT, 0644);
-		if (fd < 0) {
-			log_error("unable to create pid file: %m");
-			exit(1);
-		}
-		pid = fork();
-		if (pid < 0) {
-			log_error("error starting daemon: %m");
-			exit(1);
-		} else if (pid)
-			exit(0);
+	sprintf(pid_buf, "%d\n", getpid());
+	if (write(pid_fd, pid_buf, strlen(pid_buf)) < strlen(pid_buf)) {
+		log_error("failed to write PID to PID file: %m");
+		exit(-1);
+	}
 
-		if (chdir("/") < 0) {
-			log_error("failed to set working dir to /: %m");
-			exit(1);
-		}
+	if ((ipc_fd = ietadm_request_listen()) < 0) {
+		log_error("unable to open ipc fd: %m");
+		exit(-1);
+	}
 
-		if (lockf(fd, F_TLOCK, 0) < 0) {
-			log_error("unable to lock pid file: %m");
-			exit(1);
-		}
-		if (ftruncate(fd, 0) < 0) {
-			log_error("failed to ftruncate the PID file: %m");
-			exit(1);
-		}
+	if ((ctrl_fd = ki->ctldev_open()) < 0) {
+		log_error("unable to open ctldev fd: %m");
+		exit(-1);
+	}
 
-		sprintf(buf, "%d\n", getpid());
-		if (write(fd, buf, strlen(buf)) < strlen(buf)) {
-			log_error("failed to write PID to PID file: %m");
-			exit(1);
-		}
+	if (!check_version()) {
+		log_error("kernel module version mismatch!");
+		exit(-1);
+	}
 
-		close(0);
-		open("/dev/null", O_RDWR);
-		dup2(0, 1);
-		dup2(0, 2);
-		setsid();
+	if ((nl_fd = nl_open()) < 0) {
+		log_error("unable to open netlink fd: %m");
+		exit(-1);
 	}
 
 	cops->init(config, &isns, &isns_ac);
 	if (isns)
 		timeout = isns_init(isns, isns_ac);
 
-	if (gid && setgid(gid) < 0)
+	if (gid && setgid(gid) < 0) {
 		log_error("unable to setgid: %m");
+		exit(-1);
+	}
 
-	if (uid && setuid(uid) < 0)
+	if (uid && setuid(uid) < 0) {
 		log_error("unable to setuid: %m");
+		exit(-1);
+	}
 
 	event_loop(timeout);
 

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