Update capture_opts in extcap_cleanup().

This fixes redundant extcap_pid handle close that could occur in
capture_opts_del_iface() which resulted in unhandled exception on
Windows.

Change-Id: I06b680fcb65cd6fd854a25fb1b01248dce3251a1
Reviewed-on: https://code.wireshark.org/review/4447
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Reviewed-by: Roland Knall <rknall@gmail.com>
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>

3 files changed, 22 insertions, 26 deletions

diff --git a/capture_opts.c b/capture_opts.c
index 4feccd79b0..9f05faf49b 100644
--- a/capture_opts.c
+++ b/capture_opts.c
@@ -70,7 +70,7 @@ capture_opts_init(capture_options *capture_opts)
   capture_opts->default_options.extcap          = NULL;
   capture_opts->default_options.extcap_fifo     = NULL;
   capture_opts->default_options.extcap_args     = NULL;
-  capture_opts->default_options.extcap_pid      = (GPid)-1;
+  capture_opts->default_options.extcap_pid      = INVALID_EXTCAP_PID;
 #endif
 #if defined(_WIN32) || defined(HAVE_PCAP_CREATE)
   capture_opts->default_options.buffer_size     = DEFAULT_CAPTURE_BUFFER_SIZE;
@@ -610,7 +610,7 @@ capture_opts_add_iface_opt(capture_options *capture_opts, const char *optarg_str
     interface_opts.extcap = g_strdup(capture_opts->default_options.extcap);
     interface_opts.extcap_fifo = g_strdup(capture_opts->default_options.extcap_fifo);
     interface_opts.extcap_args = NULL;
-    interface_opts.extcap_pid = (GPid)-1;
+    interface_opts.extcap_pid = INVALID_EXTCAP_PID;
 #endif
 #if defined(_WIN32) || defined(HAVE_PCAP_CREATE)
     interface_opts.buffer_size = capture_opts->default_options.buffer_size;
@@ -1046,7 +1046,7 @@ capture_opts_del_iface(capture_options *capture_opts, guint if_index)
     g_free(interface_opts.extcap_fifo);
     if (interface_opts.extcap_args)
         g_hash_table_unref(interface_opts.extcap_args);
-    if (interface_opts.extcap_pid > 0)
+    if (interface_opts.extcap_pid != INVALID_EXTCAP_PID)
         g_spawn_close_pid(interface_opts.extcap_pid);
 #endif
 #ifdef HAVE_PCAP_REMOTE
@@ -1094,7 +1094,7 @@ collect_ifaces(capture_options *capture_opts)
       interface_opts.extcap = g_strdup(device.if_info.extcap);
       interface_opts.extcap_fifo = NULL;
       interface_opts.extcap_args = device.external_cap_args_settings;
-      interface_opts.extcap_pid = (GPid)-1;
+      interface_opts.extcap_pid = INVALID_EXTCAP_PID;
       if (interface_opts.extcap_args)
          g_hash_table_ref(interface_opts.extcap_args);
 #endif
diff --git a/capture_opts.h b/capture_opts.h
index ca87b18112..c730a7d4d7 100644
--- a/capture_opts.h
+++ b/capture_opts.h
@@ -206,6 +206,12 @@ typedef struct link_row_tag {
     gint dlt;
 } link_row;
 
+#ifdef WIN32
+#define INVALID_EXTCAP_PID INVALID_HANDLE_VALUE
+#else
+#define INVALID_EXTCAP_PID (GPid)-1
+#endif
+
 typedef struct interface_options_tag {
     gchar *name; /* the name of the interface provided to winpcap/libpcap to specify the interface */
     gchar *descr;
@@ -220,7 +226,7 @@ typedef struct interface_options_tag {
     gchar *extcap;
     gchar *extcap_fifo;
     GHashTable *extcap_args;
-    GPid extcap_pid;
+    GPid extcap_pid; /* pid of running process or INVALID_EXTCAP_PID */
     guint extcap_child_watch;
 #endif
 #if defined(_WIN32) || defined(HAVE_PCAP_CREATE)
diff --git a/extcap.c b/extcap.c
index 45801df166..1ec64fe055 100644
--- a/extcap.c
+++ b/extcap.c
@@ -434,20 +434,18 @@ void extcap_cleanup(capture_options * capture_opts) {
 			interface_opts.extcap_child_watch = 0;
 		}
 
-#ifdef WIN32
-		if (interface_opts.extcap_pid != INVALID_HANDLE_VALUE)
+		if (interface_opts.extcap_pid != INVALID_EXTCAP_PID)
 		{
+#ifdef WIN32
 			TerminateProcess(interface_opts.extcap_pid, 0);
+#endif
 			g_spawn_close_pid(interface_opts.extcap_pid);
-			interface_opts.extcap_pid = INVALID_HANDLE_VALUE;
-		}
-#else
-		if (interface_opts.extcap_pid != (GPid)-1 )
-		{
-			g_spawn_close_pid(interface_opts.extcap_pid);
-			interface_opts.extcap_pid = (GPid)-1;
+			interface_opts.extcap_pid = INVALID_EXTCAP_PID;
 		}
-#endif
+
+		/* Make sure modified interface_opts is saved in capture_opts. */
+		capture_opts->ifaces = g_array_remove_index(capture_opts->ifaces, icnt);
+		g_array_insert_val(capture_opts->ifaces, icnt, interface_opts);
 	}
 }
 
@@ -479,11 +477,7 @@ static void extcap_child_watch_cb(GPid pid, gint status _U_, gpointer user_data)
 		interface_opts = g_array_index(capture_opts->ifaces, interface_options, i);
 		if (interface_opts.extcap_pid == pid)
 		{
-#ifdef WIN32
-			interface_opts.extcap_pid = INVALID_HANDLE_VALUE;
-#else
-			interface_opts.extcap_pid = (GPid)-1;
-#endif
+			interface_opts.extcap_pid = INVALID_EXTCAP_PID;
 			interface_opts.extcap_child_watch = 0;
 			capture_opts->ifaces = g_array_remove_index(capture_opts->ifaces, i);
 			g_array_insert_val(capture_opts->ifaces, i, interface_opts);
@@ -503,11 +497,7 @@ extcaps_init_initerfaces(capture_options *capture_opts)
 	for (i = 0; i < capture_opts->ifaces->len; i++)
 	{
 		GPtrArray *args = NULL;
-#ifdef WIN32
-		GPid pid = INVALID_HANDLE_VALUE;
-#else
-		GPid pid = 0;
-#endif
+		GPid pid = INVALID_EXTCAP_PID;
 		gchar **tmp;
 		int tmp_i;
 
@@ -566,7 +556,7 @@ extcaps_init_initerfaces(capture_options *capture_opts)
 		 *
 		 * Minimum supported version of Windows: XP / Server 2003.
 		 */
-		if (pid != INVALID_HANDLE_VALUE)
+		if (pid != INVALID_EXTCAP_PID)
 		{
 			DWORD dw;
 			HANDLE handles[2];