Add options to gpspipe to run as a daemon...

...to write output to a file (instead of stdout), and to sleep for ten
seconds before attempting to connect to gpsd (useful when running from
/etc/init.d/ as a daemon).

1 files changed, 92 insertions, 5 deletions

diff --git a/gpspipe.c b/gpspipe.c
index aeb3946b..ea786004 100644
--- a/gpspipe.c
+++ b/gpspipe.c
@@ -45,6 +45,42 @@ static void spinner(unsigned int, unsigned int);
 static struct termios oldtio, newtio;
 static char serbuf[255];
 
+/* Daemonize me. */
+static void daemonize(void) {
+  int i;
+
+  /* Run as my child. */
+  i=fork();
+  if (i<0) exit(1); /* fork error */
+  if (i>0) exit(0); /* parent exits */
+
+  /* Obtain a new process group. */
+  setsid();
+
+  /* Close all open descriptors. */
+  for(i=getdtablesize();i>=0;--i)
+    close(i);
+
+  /* Reopen STDIN, STDOUT, STDERR to /dev/null. */
+  i=open("/dev/null",O_RDWR); /* STDIN */
+  dup(i); /* STDOUT */
+  dup(i); /* STDERR */
+
+  /* Know thy mask. */
+  umask(027);
+
+  /* Run from a known spot. */
+  chdir("/");
+
+  /* Catch child sig */
+  signal(SIGCHLD,SIG_IGN);
+
+ /* Ignore tty signals */
+  signal(SIGTSTP,SIG_IGN);
+  signal(SIGTTOU,SIG_IGN);
+  signal(SIGTTIN,SIG_IGN);
+}
+
 /* open the serial port and set it up */
 static void open_serial(char* device) 
 {
@@ -83,17 +119,21 @@ static void usage(void)
 {
     (void)fprintf(stderr, "Usage: gpspipe [OPTIONS] [server[:port[:device]]]\n\n"
 		  "SVN ID: $Id$ \n"
+		  "-d Run as a daemon.\n"
+		  "-f [file] Write output to file.\n"
 		  "-h Show this help.\n"
 		  "-r Dump raw NMEA.\n"
 		  "-R Dump super-raw mode (GPS binary).\n"
 		  "-w Dump gpsd native data.\n"
 		  "-j Turn on server-side buffering.\n"
+		  "-l Sleep for ten seconds before connecting to gpsd.\n"
 		  "-t Time stamp the data.\n"
 		  "-s [serial dev] emulate a 4800bps NMEA GPS on serial port (use with '-r').\n"
 		  "-n [count] exit after count packets.\n"
 		  "-v Print a little spinner.\n"
 		  "-V Print version and exit.\n\n"
 		  "You must specify one, or both, of -r/-w.\n"
+		  "You must use -f if you use -d.\n"
 	);
 }
 
@@ -103,17 +143,22 @@ int main( int argc, char **argv)
     char buf[4096];
     ssize_t wrote = 0;
     bool timestamp = false;
+    bool daemon = false;
+    bool binary = false;
+    bool sleepy = false;
     bool new_line = true;
     long count = -1;
     int option;
     unsigned int vflag = 0, l = 0;
+    FILE * fd;
 
     char *arg = NULL, *colon1, *colon2, *device = NULL; 
     char *port = DEFAULT_GPSD_PORT, *server = "127.0.0.1";
     char *serialport = NULL;
+    char *filename = NULL;
 
     buf[0] = '\0';
-    while ((option = getopt(argc, argv, "?hrRwjtvVn:s:")) != -1) {
+    while ((option = getopt(argc, argv, "?dlhrRwjtvVn:s:f:")) != -1) {
 	switch (option) {
 	case 'n':
 	    count = strtol(optarg, 0, 0);
@@ -122,8 +167,15 @@ int main( int argc, char **argv)
 	    (void)strlcat(buf, "r=1;", sizeof(buf));
 	    break;
 	case 'R':
+ 	    binary=true;
 	    (void)strlcat(buf, "r=2;", sizeof(buf));
 	    break;
+	case 'd':
+	    daemon = true;
+	    break;
+	case 'l':
+	    sleepy = true;
+	    break;
 	case 't':
 	    timestamp = true;
 	    break;
@@ -142,6 +194,9 @@ int main( int argc, char **argv)
 	case 's':
 	    serialport = optarg;
 	    break;
+	case 'f':
+	    filename = optarg;
+	    break;
 	case '?':
 	case 'h':
 	default:
@@ -155,6 +210,11 @@ int main( int argc, char **argv)
 	exit(1);
     }
 
+    if (filename==NULL && daemon==true) {
+	(void)fprintf(stderr, "gpsipipe: use of '-d' requires '-f'.\n");
+	exit(1);
+    }
+
     if (strstr(buf, "r=")==NULL && strstr(buf, "w=1")==NULL) {
 	(void)fprintf(stderr, "gpspipe: one of '-R', '-r' or '-w' is required.\n");
 	exit(1);
@@ -187,6 +247,33 @@ int main( int argc, char **argv)
     }
     /*@ +branchstate @*/
 
+    /* Sleep for ten seconds if the user requested it. */
+    if (sleepy)
+      sleep(10);
+
+    /* Daemonize if the user requested it. */
+    if (daemon)
+      daemonize();
+
+    /* Open the output file if the user requested it.  If the user
+       requested '-R', we use the 'b' flag in fopen() to "do the right
+       thing" in non-linux/unix OSes. */
+    if (filename==NULL) {
+      fd = stdout;
+    } else {
+      if (binary)
+	fd = fopen(filename,"wb");
+      else
+	fd = fopen(filename,"w");
+
+      if (fd < 0) {
+	(void)fprintf(stderr, 
+		      "gpspipe: unable to open output file:  %s\n",
+		      filename);
+	exit(1);
+      }
+    }
+
     /* Open the serial port and set it up. */
     if (serialport)
 	open_serial(serialport);
@@ -209,7 +296,7 @@ int main( int argc, char **argv)
 	exit(1);
     }
 
-    if (isatty(STDERR_FILENO) == 0)
+    if ((isatty(STDERR_FILENO) == 0) || (daemon==true))
 	vflag = 0;
 
     for(;;) {
@@ -230,14 +317,14 @@ int main( int argc, char **argv)
 		    time_t now = time(NULL);
 
 		    new_line = 0;
-		    if (fprintf(stdout, "%.24s :", ctime(&now)) <= 0) {
+		    if (fprintf(fd, "%.24s :", ctime(&now)) <= 0) {
 			(void)fprintf(stderr,
 				      "gpspipe: write error, %s(%d)\n",
 				      strerror(errno), errno);
 			exit(1);
 		    }
 		}
-		if (fputc(c, stdout) == EOF) {
+		if (fputc(c, fd) == EOF) {
 		    fprintf( stderr, "gpspipe: Write Error, %s(%d)\n",
 			     strerror(errno), errno);
 		    exit(1);
@@ -256,7 +343,7 @@ int main( int argc, char **argv)
 
 		    new_line = true;
 		    /* flush after every good line */
-		    if (fflush(stdout)) {
+		    if (fflush(fd)) {
 			(void)fprintf(stderr, "gpspipe: fflush Error, %s(%d)\n",
 				strerror(errno), errno);
 			exit(1);