Make dhclient use a pid file. Modify the rc script accordingly; while

there, clean it up and add some error checks.

Glanced at by:	brooks@
MFC after:	3 weeks

1 files changed, 34 insertions, 1 deletions

diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
index afb6d63..0521730 100644
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -95,6 +95,9 @@ struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } };
 struct in_addr inaddr_any;
 struct sockaddr_in sockaddr_broadcast;
 
+char *path_dhclient_pidfile;
+struct pidfh *pidfile;
+
 /*
  * ASSERT_STATE() does nothing now; it used to be
  * assert (state_is == state_shouldbe).
@@ -316,6 +319,8 @@ die:
 	if (ifi->client->alias)
 		script_write_params("alias_", ifi->client->alias);
 	script_go();
+	if (pidfile != NULL)
+		pidfile_remove(pidfile);
 	exit(1);
 }
 
@@ -327,12 +332,13 @@ main(int argc, char *argv[])
 	int			 pipe_fd[2];
 	int			 immediate_daemon = 0;
 	struct passwd		*pw;
+	pid_t			 otherpid;
 
 	/* Initially, log errors to stderr as well as to syslogd. */
 	openlog(__progname, LOG_PID | LOG_NDELAY, DHCPD_LOG_FACILITY);
 	setlogmask(LOG_UPTO(LOG_DEBUG));
 
-	while ((ch = getopt(argc, argv, "bc:dl:qu")) != -1)
+	while ((ch = getopt(argc, argv, "bc:dl:p:qu")) != -1)
 		switch (ch) {
 		case 'b':
 			immediate_daemon = 1;
@@ -346,6 +352,9 @@ main(int argc, char *argv[])
 		case 'l':
 			path_dhclient_db = optarg;
 			break;
+		case 'p':
+			path_dhclient_pidfile = optarg;
+			break;
 		case 'q':
 			quiet = 1;
 			break;
@@ -362,6 +371,21 @@ main(int argc, char *argv[])
 	if (argc != 1)
 		usage();
 
+	if (path_dhclient_pidfile == NULL) {
+		asprintf(&path_dhclient_pidfile,
+		    "%sdhclient.%s.pid", _PATH_VARRUN, *argv);
+		if (path_dhclient_pidfile == NULL)
+			error("asprintf");
+	}
+	pidfile = pidfile_open(path_dhclient_pidfile, 0600, &otherpid);
+	if (pidfile == NULL) {
+		if (errno == EEXIST)
+			error("dhclient already running, pid: %d.", otherpid);
+		if (errno == EAGAIN)
+			error("dhclient already running.");
+		warning("Cannot open or create pidfile: %m");
+	}
+
 	if ((ifi = calloc(1, sizeof(struct interface_info))) == NULL)
 		error("calloc");
 	if (strlcpy(ifi->name, argv[0], IFNAMSIZ) >= IFNAMSIZ)
@@ -385,6 +409,12 @@ main(int argc, char *argv[])
 
 	read_client_conf();
 
+	/* The next bit is potentially very time-consuming, so write out
+	   the pidfile right away.  We will write it out again with the
+	   correct pid after daemonizing. */
+	if (pidfile != NULL)
+		pidfile_write(pidfile);
+
 	if (!interface_link_status(ifi->name)) {
 		fprintf(stderr, "%s: no link ...", ifi->name);
 		fflush(stderr);
@@ -2298,6 +2328,9 @@ go_daemon(void)
 	if (daemon(1, 0) == -1)
 		error("daemon");
 
+	if (pidfile != NULL)
+		pidfile_write(pidfile);
+
 	/* we are chrooted, daemon(3) fails to open /dev/null */
 	if (nullfd != -1) {
 		dup2(nullfd, STDIN_FILENO);