Improve daemon synchronization, fix err msgs

Add a pipe from child to parent when running in the
background (daemon mode), so that the parent does not exit
until the child is ready for business, so that systemd does
not send us work too early. Also, fix error messages,
adding newlines where needed, and printing them to
stderr.

2 files changed, 31 insertions, 10 deletions

diff --git a/iscsiuio/src/unix/logger.c b/iscsiuio/src/unix/logger.c
index d41f9e8..87e16cd 100644
--- a/iscsiuio/src/unix/logger.c
+++ b/iscsiuio/src/unix/logger.c
@@ -135,7 +135,7 @@ int init_logger(char *filename)
 	}
 	main_log.fp = fopen(filename, "a");
 	if (main_log.fp == NULL) {
-		printf("Could not create log file: %s <%s>\n",
+		fprintf(stderr, "WARN: Could not create log file: %s <%s>\n",
 		       filename, strerror(errno));
 		rc = -EIO;
 	}
diff --git a/iscsiuio/src/unix/main.c b/iscsiuio/src/unix/main.c
index 370f8dc..5106ebe 100644
--- a/iscsiuio/src/unix/main.c
+++ b/iscsiuio/src/unix/main.c
@@ -146,7 +146,7 @@ signal_wait:
 		fini_logger(SHUTDOWN_LOGGER);
 		rc = init_logger(main_log.log_file);
 		if (rc != 0)
-			printf("Could not initialize the logger in "
+			fprintf(stderr, "WARN: Could not initialize the logger in "
 			       "signal!\n");
 		goto signal_wait;
 	default:
@@ -239,6 +239,7 @@ int main(int argc, char *argv[])
 	int foreground = 0;
 	pid_t pid;
 	pthread_attr_t attr;
+	int pipefds[2];
 
 	/*  Record the start time for the user space daemon */
 	opt.start_time = time(NULL);
@@ -281,7 +282,7 @@ int main(int argc, char *argv[])
 		/*  initialize the logger */
 		rc = init_logger(main_log.log_file);
 		if (rc != 0 && opt.debug == DEBUG_ON)
-			printf("WARN: Could not initialize the logger\n");
+			fprintf(stderr, "WARN: Could not initialize the logger\n");
 	}
 
 	LOG_INFO("Started iSCSI uio stack: Ver " PACKAGE_VERSION);
@@ -316,38 +317,53 @@ int main(int argc, char *argv[])
 
 		fd = open(pid_file, O_WRONLY | O_CREAT, 0644);
 		if (fd < 0) {
-			printf("Unable to create pid file: %s", pid_file);
+			fprintf(stderr, "ERR: Unable to create pid file: %s\n",
+				pid_file);
+			exit(1);
+		}
+
+		if (pipe(pipefds) < 0) {
+			fprintf(stderr, "ERR: Unable to create a PIPE: %s\n",
+				strerror(errno));
 			exit(1);
 		}
 
 		pid = fork();
 		if (pid < 0) {
-			printf("Starting daemon failed");
+			fprintf(stderr, "ERR: Starting daemon failed\n");
 			exit(1);
 		} else if (pid) {
+			char msgbuf[4];
+
+			/* parent: wait for child msg then exit */
+			close(pipefds[1]);
+			read(pipefds[0], msgbuf, sizeof(msgbuf));
 			exit(0);
 		}
 
+		/* the child */
 		rc = chdir("/");
 		if (rc == -1)
-			printf("Unable to chdir(\") [%s]", strerror(errno));
+			fprintf(stderr, "WARN: Unable to chdir(\") [%s]\n", strerror(errno));
 
 		if (lockf(fd, F_TLOCK, 0) < 0) {
-			printf("Unable to lock pid file: %s [%s]",
+			fprintf(stderr, "ERR: Unable to lock pid file: %s [%s]\n",
 			       pid_file, strerror(errno));
 			exit(1);
 		}
 
 		rc = ftruncate(fd, 0);
 		if (rc == -1)
-			printf("ftruncate(%d, 0) failed [%s]",
+			fprintf(stderr, "WARN: ftruncate(%d, 0) failed [%s]\n",
 			       fd, strerror(errno));
 
 		sprintf(buf, "%d\n", getpid());
 		written_bytes = write(fd, buf, strlen(buf));
-		if (written_bytes == -1)
-			printf("Could not write pid file [%s]",
+		if (written_bytes == -1) {
+			fprintf(stderr, "ERR: Could not write pid file [%s]\n",
 			       strerror(errno));
+			exit(1);
+		}
 		close(fd);
 
 		daemon_init();
@@ -393,6 +409,11 @@ int main(int argc, char *argv[])
 	if (rc != 0)
 		goto error;
 
+	/* signal parent they can go away now */
+	close(pipefds[0]);
+	write(pipefds[1], "ok\n", 3);
+	close(pipefds[1]);
+
 	/*  NetLink connection to listen to NETLINK_ISCSI private messages */
 	if (nic_nl_open() != 0)
 		goto error;