Have the routines to get interface lists take a pointer to a "gchar *"

[obnox/wireshark/wip.git] / capture-pcap-util-unix.c

diff --git a/capture-pcap-util-unix.c b/capture-pcap-util-unix.c
index bfb124c538db8711ad31fdee0e2b4d209b9eb23e..ea8968b7d0322b8360684c843f3b887c683fe81e 100644 (file)
--- a/capture-pcap-util-unix.c
+++ b/capture-pcap-util-unix.c
@@ -74,7 +74,7 @@ search_for_if_cb(gpointer data, gpointer user_data);
 #endif
 
 GList *
-get_interface_list(int *err, char *err_str)
+get_interface_list(int *err, char **err_str)
 {
 #ifdef HAVE_PCAP_FINDALLDEVS
        return get_interface_list_findalldevs(err, err_str);
@@ -90,11 +90,15 @@ get_interface_list(int *err, char *err_str)
        int len, lastlen;
        char *buf;
        if_info_t *if_info;
+       char errbuf[PCAP_ERRBUF_SIZE];
 
        if (sock < 0) {
                *err = CANT_GET_INTERFACE_LIST;
-               g_snprintf(err_str, PCAP_ERRBUF_SIZE, "Error opening socket: %s",
-                   strerror(errno));
+               if (err_str != NULL) {
+                       *err_str = g_strdup_printf(
+                           "Can't get list of interfaces: error opening socket: %s",
+                           strerror(errno));
+               }
                return NULL;
        }
 
@@ -111,15 +115,19 @@ get_interface_list(int *err, char *err_str)
                memset (buf, 0, len);
                if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
                        if (errno != EINVAL || lastlen != 0) {
-                               g_snprintf(err_str, PCAP_ERRBUF_SIZE,
-                                       "SIOCGIFCONF ioctl error getting list of interfaces: %s",
-                                       strerror(errno));
+                               if (err_str != NULL) {
+                                       *err_str = g_strdup_printf(
+                                           "Can't get list of interfaces: SIOCGIFCONF ioctl error: %s",
+                                           strerror(errno));
+                               }
                                goto fail;
                        }
                } else {
                        if ((unsigned) ifc.ifc_len < sizeof(struct ifreq)) {
-                               g_snprintf(err_str, PCAP_ERRBUF_SIZE,
-                                       "SIOCGIFCONF ioctl gave too small return buffer");
+                               if (err_str != NULL) {
+                                       *err_str = g_strdup(
+                                           "Can't get list of interfaces: SIOCGIFCONF ioctl gave too small return buffer");
+                               }
                                goto fail;
                        }
                        if (ifc.ifc_len == lastlen)
@@ -165,9 +173,11 @@ get_interface_list(int *err, char *err_str)
                if (ioctl(sock, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
                        if (errno == ENXIO)
                                goto next;
-                       g_snprintf(err_str, PCAP_ERRBUF_SIZE,
-                               "SIOCGIFFLAGS error getting flags for interface %s: %s",
-                           ifr->ifr_name, strerror(errno));
+                       if (err_str != NULL) {
+                               *err_str = g_strdup_printf(
+                                   "Can't get list of interfaces: SIOCGIFFLAGS error getting flags for interface %s: %s",
+                                   ifr->ifr_name, strerror(errno));
+                       }
                        goto fail;
                }
 
@@ -184,7 +194,7 @@ get_interface_list(int *err, char *err_str)
                 * supplied is too large, rather than just truncating it.
                 */
                pch = pcap_open_live(ifr->ifr_name, MIN_PACKET_SIZE, 0, 0,
-                   err_str);
+                   errbuf);
                if (pch == NULL)
                        goto next;
                pcap_close(pch);
@@ -230,7 +240,7 @@ get_interface_list(int *err, char *err_str)
         * Try opening it and, if that succeeds, add it to the end of
         * the list of interfaces.
         */
-       pch = pcap_open_live("any", MIN_PACKET_SIZE, 0, 0, err_str);
+       pch = pcap_open_live("any", MIN_PACKET_SIZE, 0, 0, errbuf);
        if (pch != NULL) {
                /*
                 * It worked; we can use the "any" device.
@@ -250,6 +260,8 @@ get_interface_list(int *err, char *err_str)
                 * No interfaces found.
                 */
                *err = NO_INTERFACES_FOUND;
+               if (err_str != NULL)
+                       *err_str = NULL;
        }
        return il;