[uml-devel] tunctl brief output option

[Christian L. <xi...@bo...>]

Here is a small patch that adds a -b switch to tunctl.

When used the output will be brief meaning that just
the device name will be printed out on a line by itself.

This allows me to easily get the device name in a shell
script like this:

TUNDEV=`tunctl -b -u uml02`

The patch:

Index: tunctl.c
===================================================================
RCS file: /cvsroot/user-mode-linux/tools/tunctl/tunctl.c,v
retrieving revision 1.2
diff -u -w -r1.2 tunctl.c
--- tunctl.c	18 Mar 2002 19:38:49 -0000	1.2
+++ tunctl.c	6 Sep 2002 15:02:25 -0000
@@ -15,12 +15,13 @@
 
 static void Usage(char *name)
 {
-  fprintf(stderr, "Create: %s [-u owner] [-t device-name] "
+  fprintf(stderr, "Create: %s [-b] [-u owner] [-t device-name] "
 	  "[-f tun-clone-device]\n", name);
   fprintf(stderr, "Delete: %s -d device-name [-f tun-clone-device]\n\n", 
 	  name);
   fprintf(stderr, "The default tun clone device is /dev/net/tun - some systems"
-	  " use\n/dev/misc/net/tun instead\n");
+	  " use\n/dev/misc/net/tun instead\n\n");
+  fprintf(stderr, "-b will result in brief output (just the device name)\n");
   exit(1);
 }
 
@@ -29,11 +30,14 @@
   struct ifreq ifr;
   struct passwd *pw;
   long owner = geteuid();
-  int tap_fd, opt, delete = 0;
+  int tap_fd, opt, delete = 0, brief = 0;
   char *tun = "", *file = "/dev/net/tun", *name = argv[0], *end;
 
-  while((opt = getopt(argc, argv, "df:ht:u:")) > 0){
+  while((opt = getopt(argc, argv, "bdf:ht:u:")) > 0){
     switch(opt) {
+      case 'b':
+        brief = 1;
+        break;
       case 'd':
         delete = 1;
         break;
@@ -101,6 +105,9 @@
       perror("TUNSETPERSIST");
       exit(1);
     } 
+    if(brief)
+      printf("%s\n", ifr.ifr_name);
+    else
     printf("Set '%s' persistent and owned by uid %ld\n", ifr.ifr_name, owner);
   }
   return(0);


-- 
Best regards
    Christian Laursen