Report syntax errors in UAT prefs parsing

Add the cause for a syntax error while parsing UATs. Example output:

    $ tshark -ouat:ssl_keys:,
    tshark: Invalid -o flag "uat:ssl_keys:,": ssl_keys:1: No IP address given.
    $ tshark -ouat:unknown:,
    tshark: Invalid -o flag "uat:unknown:,": Unknown preference

Change-Id: I549406c4e31a81d29f487ef47bdb3c22da084947
Reviewed-on: https://code.wireshark.org/review/21748
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Jakub Zawadzki <darkjames-ws@darkjames.pl>
Reviewed-by: Michael Mann <mmann78@netscape.net>

1 files changed, 8 insertions, 2 deletions

diff --git a/tshark.c b/tshark.c
index e4d4551c96..c0fff87686 100644
--- a/tshark.c
+++ b/tshark.c
@@ -1208,13 +1208,18 @@ main(int argc, char *argv[])
 #endif
       break;
     case 'o':        /* Override preference from command line */
-      switch (prefs_set_pref(optarg)) {
+    {
+      char *errmsg = NULL;
+
+      switch (prefs_set_pref(optarg, &errmsg)) {
 
       case PREFS_SET_OK:
         break;
 
       case PREFS_SET_SYNTAX_ERR:
-        cmdarg_err("Invalid -o flag \"%s\"", optarg);
+        cmdarg_err("Invalid -o flag \"%s\"%s%s", optarg,
+            errmsg ? ": " : "", errmsg ? errmsg : "");
+        g_free(errmsg);
         exit_status = INVALID_OPTION;
         goto clean_exit;
         break;
@@ -1227,6 +1232,7 @@ main(int argc, char *argv[])
         break;
       }
       break;
+    }
     case 'q':        /* Quiet */
       quiet = TRUE;
       break;