Make slattach create a PID file under /var/run when the connection is

established.  This way, automatic scripts are possible that might
control the SLIP connection.  It's unacceptable for a daemon that's
being controlled by a variety of signals to not leave its PID
somewhere.  The file name contains the terminal path name component of
the associated tty device, so it should be unique even with multiple
parallel slattach's running.  The file will be unlinked at regular exit.

Also found a minor bug in the option handling by compiling with -Wall.

1 files changed, 21 insertions, 3 deletions

diff --git a/sbin/slattach/slattach.c b/sbin/slattach/slattach.c
index a773493..f89bc7d 100644
--- a/sbin/slattach/slattach.c
+++ b/sbin/slattach/slattach.c
@@ -89,6 +89,7 @@ int	exiting = 0;		/* allready running exit_handler */
 struct	termios tty;		/* tty configuration/state */
 
 char	tty_path[32];		/* path name of the tty (e.g. /dev/tty01) */
+char	pidfilename[40];	/* e.g. /var/run/slattach.tty01.pid */
 char	*redial_cmd = 0;	/* command to exec upon shutdown. */
 char	*config_cmd = 0;	/* command to exec if slip unit changes. */
 char	*exit_cmd = 0;		/* command to exec before exiting. */
@@ -112,6 +113,7 @@ int main(int argc, char **argv)
 	int option;
 	extern char *optarg;
 	extern int optind;
+	char *cp;
 
 	while ((option = getopt(argc, argv, "ace:fhlnr:s:u:z")) != EOF) {
 		switch (option) {
@@ -152,7 +154,7 @@ int main(int argc, char **argv)
 			break;
 		default:
 			fprintf(stderr, "%s: Invalid option -- '%c'\n",
-			  option);
+				argv[0], option);
 		case '?':
 			fprintf(stderr, usage_str, argv[0]);
 			exit_handler(1);
@@ -179,7 +181,11 @@ int main(int argc, char **argv)
 		strncat(tty_path, dev, 10);
 		dev = tty_path;
 	}
-
+	cp = strrchr(dev, '/'); /* always succeeds */
+	cp++;			/* trailing tty pathname component */
+	sprintf(pidfilename, "%sslattach.%s.pid", _PATH_VARRUN, cp);
+	printf("%s\n",pidfilename);
+	
 	if (!foreground)
 		daemon(0,0);	/* fork, setsid, chdir /, and close std*. */
 	/* daemon() closed stderr, so log errors from here on. */
@@ -225,7 +231,7 @@ int main(int argc, char **argv)
 void acquire_line()
 {
 	int ttydisc = TTYDISC;
-	int pgrp;
+	FILE *pidfile;
 
 	ioctl(fd, TIOCSETD, &ttydisc); /* reset to tty discipline */
 
@@ -241,6 +247,14 @@ void acquire_line()
 	while (getppid () != 1)
 		sleep (1);	/* Wait for parent to die. */
 
+	/* create PID file */
+	if((pidfile = fopen(pidfilename, "w")) == NULL) {
+		syslog(LOG_NOTICE,"cannot create PID file: %m");
+	} else {
+		fprintf(pidfile, "%ld\n", getpid());
+		fclose(pidfile);
+	}
+	
 	if ((int)signal(SIGHUP,sighup_handler) < 0) /* Re-enable HUP signal */
 		syslog(LOG_NOTICE,"cannot install SIGHUP handler: %m");
 
@@ -438,6 +452,10 @@ void exit_handler(int ret)
 	 */
 	if (fd != -1)
 		close(fd);
+
+	/* Remove the PID file */
+	(void)unlink(pidfilename);
+
 	/* invoke a shell for exit_cmd. */
 	if (exit_cmd) {
 		syslog(LOG_NOTICE,"exiting after running %s", exit_cmd);