forked from osmocom/wireshark
![Guy Harris](/assets/img/avatar_default.png)
Add an FT_STRINGZPAD type, for null-padded strings (typically fixed-length fields, where the string can be up to the length of the field, and is null-padded if it's shorter than that), and use it. Use IS_FT_STRING() in more cases, so that less code needs to know what types are string types. Add a tvb_get_stringzpad() routine, which gets null-padded strings. Currently, it does the same thing that tvb_get_string_enc() does, but that might change if we don't store string values as null-terminated strings. Change-Id: I46f56e130de8f419a19b56ded914e24cc7518a66 Reviewed-on: https://code.wireshark.org/review/1082 Reviewed-by: Guy Harris <guy@alum.mit.edu>
300 lines
8.5 KiB
C
300 lines
8.5 KiB
C
/* decode_as_utils.c
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*
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* Routines to modify dissector tables on the fly.
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*
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* By David Hampton <dhampton@mac.com>
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* Copyright 2001 David Hampton
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <stdlib.h>
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#include <stdio.h>
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#include <errno.h>
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#include "epan/decode_as.h"
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#include "epan/packet.h"
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#include "epan/prefs.h"
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#include "epan/prefs-int.h"
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#include "epan/dissectors/packet-dcerpc.h"
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#include "ui/decode_as_utils.h"
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#include "ui/simple_dialog.h"
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#include "wsutil/file_util.h"
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#include "wsutil/filesystem.h"
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#include "version_info.h"
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/*
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* A list of dissectors that need to be reset.
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*/
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static GSList *dissector_reset_list = NULL;
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/*
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* Data structure used as user data when iterating dissector handles
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*/
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typedef struct lookup_entry {
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gchar* dissector_short_name;
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dissector_handle_t handle;
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} lookup_entry_t;
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/*
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* Data structure for tracking which dissector need to be reset. This
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* structure is necessary as a hash table entry cannot be removed
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* while a g_hash_table_foreach walk is in progress.
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*/
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typedef struct dissector_delete_item {
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/* The name of the dissector table */
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const gchar *ddi_table_name;
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/* The type of the selector in that dissector table */
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ftenum_t ddi_selector_type;
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/* The selector in the dissector table */
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union {
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guint sel_uint;
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char *sel_string;
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} ddi_selector;
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} dissector_delete_item_t;
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/*
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* A callback function to changed a dissector_handle if matched
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* This is used when iterating a dissector table
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*/
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static void
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change_dissector_if_matched(gpointer item, gpointer user_data)
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{
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dissector_handle_t handle = (dissector_handle_t)item;
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lookup_entry_t * lookup = (lookup_entry_t *)user_data;
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if (strcmp(lookup->dissector_short_name, dissector_handle_get_short_name(handle)) == 0) {
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lookup->handle = handle;
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}
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}
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/*
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* A callback function to parse each "decode as" entry in the file and apply the change
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*/
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static prefs_set_pref_e
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read_set_decode_as_entries(gchar *key, const gchar *value,
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void *user_data _U_,
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gboolean return_range_errors _U_)
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{
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gchar *values[4] = {NULL, NULL, NULL, NULL};
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gchar delimiter[4] = {',', ',', ',','\0'};
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gchar *pch;
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guint i, j;
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dissector_table_t sub_dissectors;
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prefs_set_pref_e retval = PREFS_SET_OK;
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gboolean is_valid = FALSE;
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if (strcmp(key, DECODE_AS_ENTRY) == 0) {
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/* Parse csv into table, selector, initial, current */
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for (i = 0; i < 4; i++) {
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pch = strchr(value, delimiter[i]);
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if (pch == NULL) {
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for (j = 0; j < i; j++) {
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g_free(values[j]);
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}
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return PREFS_SET_SYNTAX_ERR;
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}
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values[i] = g_strndup(value, pch - value);
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value = pch + 1;
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}
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sub_dissectors = find_dissector_table(values[0]);
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if (sub_dissectors != NULL) {
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lookup_entry_t lookup;
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ftenum_t selector_type;
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lookup.dissector_short_name = values[3];
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lookup.handle = NULL;
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selector_type = dissector_table_get_type(sub_dissectors);
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g_slist_foreach(dissector_table_get_dissector_handles(sub_dissectors),
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change_dissector_if_matched, &lookup);
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if (lookup.handle != NULL || g_ascii_strcasecmp(values[3], DECODE_AS_NONE) == 0) {
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is_valid = TRUE;
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}
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if (is_valid) {
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if (IS_FT_STRING(selector_type)) {
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dissector_change_string(values[0], values[1], lookup.handle);
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} else {
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dissector_change_uint(values[0], atoi(values[1]), lookup.handle);
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}
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decode_build_reset_list(g_strdup(values[0]), selector_type,
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g_strdup(values[1]), NULL, NULL);
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}
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} else {
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retval = PREFS_SET_SYNTAX_ERR;
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}
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} else {
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retval = PREFS_SET_NO_SUCH_PREF;
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}
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for (i = 0; i < 4; i++) {
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g_free(values[i]);
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}
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return retval;
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}
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void
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load_decode_as_entries(void)
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{
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char *daf_path;
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FILE *daf;
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if (dissector_reset_list) {
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decode_clear_all();
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}
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daf_path = get_persconffile_path(DECODE_AS_ENTRIES_FILE_NAME, TRUE);
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if ((daf = ws_fopen(daf_path, "r")) != NULL) {
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read_prefs_file(daf_path, daf, read_set_decode_as_entries, NULL);
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fclose(daf);
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}
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g_free(daf_path);
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}
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void
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decode_build_reset_list (const gchar *table_name, ftenum_t selector_type,
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gpointer key, gpointer value _U_,
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gpointer user_data _U_)
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{
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dissector_delete_item_t *item;
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item = g_new(dissector_delete_item_t,1);
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item->ddi_table_name = table_name;
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item->ddi_selector_type = selector_type;
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switch (selector_type) {
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case FT_UINT8:
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case FT_UINT16:
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case FT_UINT24:
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case FT_UINT32:
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item->ddi_selector.sel_uint = GPOINTER_TO_UINT(key);
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break;
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case FT_STRING:
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case FT_STRINGZ:
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case FT_UINT_STRING:
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case FT_STRINGZPAD:
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item->ddi_selector.sel_string = (char *)key;
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break;
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default:
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g_assert_not_reached();
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}
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dissector_reset_list = g_slist_prepend(dissector_reset_list, item);
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}
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/* clear all settings */
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void
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decode_clear_all(void)
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{
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dissector_delete_item_t *item;
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GSList *tmp;
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dissector_all_tables_foreach_changed(decode_build_reset_list, NULL);
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for (tmp = dissector_reset_list; tmp; tmp = g_slist_next(tmp)) {
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item = (dissector_delete_item_t *)tmp->data;
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switch (item->ddi_selector_type) {
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case FT_UINT8:
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case FT_UINT16:
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case FT_UINT24:
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case FT_UINT32:
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dissector_reset_uint(item->ddi_table_name,
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item->ddi_selector.sel_uint);
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break;
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case FT_STRING:
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case FT_STRINGZ:
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case FT_UINT_STRING:
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case FT_STRINGZPAD:
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dissector_reset_string(item->ddi_table_name,
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item->ddi_selector.sel_string);
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break;
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default:
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g_assert_not_reached();
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}
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g_free(item);
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}
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g_slist_free(dissector_reset_list);
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dissector_reset_list = NULL;
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decode_dcerpc_reset_all();
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}
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/* XXX - We might want to switch this to a UAT */
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FILE *
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decode_as_open(void) {
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char *pf_dir_path;
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char *daf_path;
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FILE *da_file;
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if (create_persconffile_dir(&pf_dir_path) == -1) {
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simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
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"Can't create directory\n\"%s\"\nfor recent file: %s.", pf_dir_path,
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g_strerror(errno));
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g_free(pf_dir_path);
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return NULL;
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}
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daf_path = get_persconffile_path(DECODE_AS_ENTRIES_FILE_NAME, TRUE);
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if ((da_file = ws_fopen(daf_path, "w")) == NULL) {
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simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
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"Can't open decode_as_entries file\n\"%s\": %s.", daf_path,
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g_strerror(errno));
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g_free(daf_path);
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return NULL;
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}
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fputs("# \"Decode As\" entries file for Wireshark " VERSION ".\n"
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"#\n"
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"# This file is regenerated each time \"Decode As\" preferences\n"
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"# are saved within Wireshark. Making manual changes should be safe,"
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"# however.\n", da_file);
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return da_file;
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}
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/* XXX We might want to have separate int and string routines. */
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void
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decode_as_write_entry(FILE *da_file, const char *table_name, const char *selector, const char *default_proto, const char *current_proto) {
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fprintf (da_file,
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DECODE_AS_ENTRY ": %s,%s,%s,%s\n",
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table_name, selector, default_proto, current_proto);
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}
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/*
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* Editor modelines
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*
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* Local Variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* ex: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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