add PID file handling to clients (including signal handling to remove the files)

clients/lcdproc/Makefile.am

@@ -12,7 +12,7 @@ if DARWIN
 AM_LDFLAGS = -framework CoreFoundation -framework IOKit
 endif
 
-AM_CPPFLAGS = -I$(top_srcdir) -DSYSCONFDIR=\"$(sysconfdir)\"
+AM_CPPFLAGS = -I$(top_srcdir) -DSYSCONFDIR=\"$(sysconfdir)\" -DPIDFILEDIR=\"$(pidfiledir)\"
 
 
 EXTRA_DIST = $(sysconf_DATA)

clients/lcdproc/lcdproc.conf

@@ -17,6 +17,9 @@ ReportToSyslog=false
 # run in foreground [default: false; legal: true, false]
 #Foreground=true
 
+# PidFile location when running as daemon [default: /var/run/lcdproc.pid]
+#PidFile=/var/run/lcdproc.pid
+
 # slow down initial announcement of modes (in 1/100s)
 #delay=2
 

clients/lcdproc/main.c

@@ -70,11 +70,15 @@ static int process_configfile(char *cfgfile);
 #if !defined(SYSCONFDIR)
 # define SYSCONFDIR	"/etc"
 #endif
+#if !defined(PIDFILEDIR)
+# define PIDFILEDIR	"/var/run"
+#endif
 
 #define UNSET_INT		-1
 #define UNSET_STR		"\01"
 #define DEFAULT_SERVER		"127.0.0.1"
 #define DEFAULT_CONFIGFILE	SYSCONFDIR "/lcdproc.conf"
+#define DEFAULT_PIDFILE		PIDFILEDIR "/lcdproc.pid"
 #define DEFAULT_REPORTDEST	RPT_DEST_STDERR
 #define DEFAULT_REPORTLEVEL	RPT_WARNING
 
@@ -111,6 +115,7 @@ int port	= LCDPORT;
 int foreground 	= FALSE;
 static int report_level = UNSET_INT;
 static int report_dest 	= UNSET_INT;
+char *pidfile = NULL;
 char *configfile = NULL;
 char *displayname = NULL;
 
@@ -243,7 +248,7 @@ main(int argc, char **argv)
 	/* Read config file*/
 	cfgresult = process_configfile(configfile);
 	if (cfgresult < 0) {
-		fprintf(stderr, "Error reading config file");
+		fprintf(stderr, "Error reading config file\n");
 		exit(EXIT_FAILURE);
 	}	
 
@@ -303,9 +308,22 @@ main(int argc, char **argv)
 
 	if (foreground != TRUE) {
 		if (daemon(1,0) != 0) {
-			fprintf(stderr, "Error: daemonize failed");
+			fprintf(stderr, "Error: daemonize failed\n");
 			return(EXIT_FAILURE);
 		}
+
+		if (pidfile != NULL) {
+			FILE *pidf = fopen(pidfile, "w");
+
+			if (pidf) {
+				fprintf(pidf, "%d\n", (int) getpid());
+				fclose(pidf);
+			} else {
+				fprintf(stderr, "Error creating pidfile %s: %s\n",
+					pidfile, strerror(errno));
+				return(EXIT_FAILURE);
+			}
+		}
 	}	
 
 	// Init the status gatherers...
@@ -314,10 +332,8 @@ main(int argc, char **argv)
 	// And spew stuff!
 	main_loop();
 
-	// Clean up
+	// Clean up & exit
 	exit_program(EXIT_SUCCESS);
-
-	return(0);
 }
 
 
@@ -372,6 +388,9 @@ process_configfile(char *configfile)
 	if (foreground != TRUE) {
 		foreground = config_get_bool(progname, "Foreground", 0, FALSE);
 	}
+	if (pidfile == NULL) {
+		pidfile = strdup(config_get_string(progname, "PidFile", 0, DEFAULT_PIDFILE));
+	}
 	if (islow < 0) {
 		islow = config_get_int(progname, "Delay", 0, -1);
 	}
@@ -455,6 +474,8 @@ exit_program(int val)
 	Quit = 1;
 	sock_close(sock);
 	mode_close();
+	if ((foreground != TRUE) && (pidfile != NULL))
+		unlink(pidfile);
 	exit(val);
 }