Initialize the cfilter field of a capture_opts structure to a null

pointer, so we can determine whether a capture filter has been set or
not.

Use that to check in TShark whether the user specified a filter with
"-f" or not, rather than using the no-longer-set
"capture_filter_specified" variable.

Also, check for multiple "-f" options.

If no capture filter is specified, use a null string, to work around
broken versions of Linux libpcap.

svn path=/trunk/; revision=18989

1 files changed, 11 insertions, 4 deletions

diff --git a/tshark.c b/tshark.c
index 0973870fee..ddb5bce457 100644
--- a/tshark.c
+++ b/tshark.c
@@ -677,7 +677,6 @@ main(int argc, char *argv[])
   int                  dp_open_errno, dp_read_errno;
   int                  err;
 #ifdef HAVE_LIBPCAP
-  gboolean             capture_filter_specified = FALSE;
   gboolean             list_link_layer_types = FALSE;
   gboolean             start_capture = FALSE;
 #else
@@ -1079,7 +1078,7 @@ main(int argc, char *argv[])
       default:
       case '?':        /* Bad flag - print usage message */
         switch(optopt) {
-        case'F':
+        case 'F':
           list_capture_types();
           break;
         default:
@@ -1104,7 +1103,7 @@ main(int argc, char *argv[])
       rfilter = get_args_as_string(argc, argv, optind);
     } else {
 #ifdef HAVE_LIBPCAP
-      if (capture_filter_specified) {
+      if (capture_opts.cfilter != NULL) {
         cmdarg_err("Capture filters were specified both with \"-f\""
             " and with additional command-line arguments");
         exit(1);
@@ -1148,7 +1147,7 @@ main(int argc, char *argv[])
      support in capture files we read). */
 #ifdef HAVE_LIBPCAP
   if (cf_name != NULL) {
-    if (capture_filter_specified) {
+    if (capture_opts.cfilter != NULL) {
       cmdarg_err("Only read filters, not capture filters, "
           "can be specified when reading a capture file.");
       exit(1);
@@ -1562,6 +1561,14 @@ capture(void)
    */
   relinquish_special_privs_perm();
 
+  /*
+   * Some older Linux versions of libpcap don't work right without
+   * a capture filter; if none was specified, use an empty string.
+   * (Yes, that's a libpcap bug, and has been fixed for a while.)
+   */
+  if (capture_opts.cfilter == NULL)
+    capture_opts.cfilter = g_strdup("");
+
   /* init the input filter from the network interface (capture pipe will do nothing) */
   switch (capture_loop_init_filter(ld.pcap_h, ld.from_cap_pipe, capture_opts.iface, capture_opts.cfilter)) {