- advisory file locking in the cfgfile read/write code

- changes in the init script to use the pidfile for killing
- changed the spnavcfg program, added functionality to start/stop the X11
  magellan interface, and to "ping" the server and see if it's running.


git-svn-id: svn+ssh://svn.code.sf.net/p/spacenav/code/spacenavd@23 ef983eb1-d774-4af8-acfd-baaf7b16a646

cfgfile.c

@@ -20,6 +20,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <string.h>
 #include <ctype.h>
 #include <errno.h>
+#include <fcntl.h>
 #include "cfgfile.h"
 
 enum {TX, TY, TZ, RX, RY, RZ};
@@ -35,6 +36,7 @@ int read_cfg(const char *fname, struct cfg *cfg)
 {
 	FILE *fp;
 	char buf[512];
+	struct flock flk;
 
 	default_cfg(cfg);
 
@@ -43,6 +45,12 @@ int read_cfg(const char *fname, struct cfg *cfg)
 		return -1;
 	}
 
+	/* aquire shared read lock */
+	flk.l_type = F_RDLCK;
+	flk.l_start = flk.l_len = 0;
+	flk.l_whence = SEEK_SET;
+	while(fcntl(fileno(fp), F_SETLKW, &flk) == -1);
+
 	while(fgets(buf, sizeof buf, fp)) {
 		int isnum;
 		char *key_str, *val_str, *line = buf;
@@ -104,6 +112,12 @@ int read_cfg(const char *fname, struct cfg *cfg)
 		}
 	}
 
+	/* unlock */
+	flk.l_type = F_UNLCK;
+	flk.l_start = flk.l_len = 0;
+	flk.l_whence = SEEK_SET;
+	fcntl(fileno(fp), F_SETLK, &flk);
+
 	fclose(fp);
 	return 0;
 }
@@ -111,12 +125,19 @@ int read_cfg(const char *fname, struct cfg *cfg)
 int write_cfg(const char *fname, struct cfg *cfg)
 {
 	FILE *fp;
+	struct flock flk;
 
 	if(!(fp = fopen(fname, "w"))) {
 		fprintf(stderr, "failed to write config file %s: %s\n", fname, strerror(errno));
 		return -1;
 	}
 
+	/* aquire exclusive write lock */
+	flk.l_type = F_WRLCK;
+	flk.l_start = flk.l_len = 0;
+	flk.l_whence = SEEK_SET;
+	while(fcntl(fileno(fp), F_SETLKW, &flk) == -1);
+
 	fprintf(fp, "# sensitivity is multiplied with every motion (1.0 normal).\n");
 	fprintf(fp, "sensitivity = %.3f\n\n", cfg->sensitivity);
 
@@ -140,6 +161,13 @@ int write_cfg(const char *fname, struct cfg *cfg)
 		if(cfg->invert[5]) fputc('z', fp);
 		fputs("\n\n", fp);
 	}
+
+	/* unlock */
+	flk.l_type = F_UNLCK;
+	flk.l_start = flk.l_len = 0;
+	flk.l_whence = SEEK_SET;
+	fcntl(fileno(fp), F_SETLK, &flk);
+
 	fclose(fp);
 	return 0;
 }

init_script

@@ -18,7 +18,16 @@ start)
 
 stop)
 	echo 'Stopping spacenavd daemon'
-	kill `pidof spacenavd`
+	# detect daemon's process id
+	pid=`cat /tmp/.spnavd.pid 2>/dev/null`
+	if [ $? != 0 ]; then
+		pid=`ps -e | grep spacenavd | awk '{ print $1 }'`
+		if [ -z "$pid" ]; then
+			echo 'spacenavd daemon is not running, nothing to do.'
+			exit 1
+		fi
+	fi
+	kill $pid
 	;;
 
 reload|restart|force-reload)

spnavd.c

@@ -100,7 +100,7 @@ void sig_handler(int s);
 
 unsigned int msec_dif(struct timeval tv1, struct timeval tv2);
 
-int dev_fd;
+int dev_fd = -1;
 char dev_name[128];
 unsigned char evtype_mask[(EV_MAX + 7) / 8];
 #define TEST_BIT(b, ar)	(ar[b / 8] & (1 << (b % 8)))
@@ -183,10 +183,7 @@ int main(int argc, char **argv)
 	signal(SIGUSR1, sig_handler);
 	signal(SIGUSR2, sig_handler);
 
-	/* initialize the input device and the X11 connection (if available) */
-	if(init_dev() == -1) {
-		return 1;
-	}
+	init_dev();
 	init_unix();
 #ifdef USE_X11
 	init_x11();
@@ -862,11 +859,15 @@ int open_dev(const char *path)
 
 	if(ioctl(dev_fd, EVIOCGBIT(0, sizeof(evtype_mask)), evtype_mask) == -1) {
 		perror("EVIOCGBIT ioctl failed\n");
+		close(dev_fd);
+		dev_fd = -1;
 		return -1;
 	}
 
 	if(!TEST_BIT(EV_REL, evtype_mask)) {
 		fprintf(stderr, "Wrong device, no relative events reported!\n");
+		close(dev_fd);
+		dev_fd = -1;
 		return -1;
 	}
 
@@ -1030,6 +1031,7 @@ void sig_handler(int s)
 	case SIGTERM:
 		close_x11();	/* call to avoid leaving garbage in the X server's root windows */
 		close_dev();
+		remove("/tmp/.spnavd.pid");
 		exit(0);
 
 #ifdef USE_X11

spnavd_ctl

@@ -32,7 +32,7 @@ else
 fi
 
 # detect daemon's process id
-pid=`cat /tmp/.spnav.pid 2>/dev/null`
+pid=`cat /tmp/.spnavd.pid 2>/dev/null`
 if [ $? != 0 ]; then
 	pid=`ps -e | grep spacenavd | awk '{ print $1 }'`
 	if [ -z "$pid" ]; then