2 * Routines for packet capture windows
6 * Wireshark - Network traffic analyzer
7 * By Gerald Combs <gerald@wireshark.org>
8 * Copyright 1998 Gerald Combs
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
26 * <laurent.deniel@free.fr>
28 * Almost completely rewritten in order to:
30 * - be able to use a unlimited number of ringbuffer files
31 * - close the current file and open (truncating) the next file at switch
32 * - set the final file name once open (or reopen)
33 * - avoid the deletion of files that could not be truncated (can't arise now)
34 * and do not erase empty files
36 * The idea behind that is to remove the limitation of the maximum # of
37 * ringbuffer files being less than the maximum # of open fd per process
38 * and to be able to reduce the amount of virtual memory usage (having only
39 * one file open at most) or the amount of file system usage (by truncating
40 * the files at switch and not the capture stop, and by closing them which
41 * makes possible their move or deletion after a switch).
67 #include "ringbuffer.h"
68 #include <wsutil/file_util.h>
71 /* Ringbuffer file structure */
72 typedef struct _rb_file {
76 /* Ringbuffer data structure */
77 typedef struct _ringbuf_data {
79 guint num_files; /* Number of ringbuffer files (1 to ...) */
80 guint curr_file_num; /* Number of the current file (ever increasing) */
81 gchar *fprefix; /* Filename prefix */
82 gchar *fsuffix; /* Filename suffix */
83 gboolean unlimited; /* TRUE if unlimited number of files */
85 int fd; /* Current ringbuffer file descriptor */
87 gboolean group_read_access; /* TRUE if files need to be opened with group read access */
90 static ringbuf_data rb_data;
94 * create the next filename and open a new binary file with that name
96 static int ringbuf_open_file(rb_file *rfile, int *err)
102 if (rfile->name != NULL) {
103 if (rb_data.unlimited == FALSE) {
104 /* remove old file (if any, so ignore error) */
105 ws_unlink(rfile->name);
113 current_time = time(NULL);
115 g_snprintf(filenum, sizeof(filenum), "%05u", (rb_data.curr_file_num + 1) % RINGBUFFER_MAX_NUM_FILES);
116 strftime(timestr, sizeof(timestr), "%Y%m%d%H%M%S", localtime(¤t_time));
117 rfile->name = g_strconcat(rb_data.fprefix, "_", filenum, "_", timestr,
118 rb_data.fsuffix, NULL);
120 if (rfile->name == NULL) {
125 rb_data.fd = ws_open(rfile->name, O_RDWR|O_BINARY|O_TRUNC|O_CREAT,
126 rb_data.group_read_access ? 0640 : 0600);
128 if (rb_data.fd == -1 && err != NULL) {
136 * Initialize the ringbuffer data structures
139 ringbuf_init(const char *capfile_name, guint num_files, gboolean group_read_access)
142 char *pfx, *last_pathsep;
145 rb_data.files = NULL;
146 rb_data.curr_file_num = 0;
147 rb_data.fprefix = NULL;
148 rb_data.fsuffix = NULL;
149 rb_data.unlimited = FALSE;
152 rb_data.group_read_access = group_read_access;
154 /* just to be sure ... */
155 if (num_files <= RINGBUFFER_MAX_NUM_FILES) {
156 rb_data.num_files = num_files;
158 rb_data.num_files = RINGBUFFER_MAX_NUM_FILES;
161 /* Check file name */
162 if (capfile_name == NULL) {
163 /* ringbuffer does not work with temporary files! */
167 /* set file name prefix/suffix */
169 save_file = g_strdup(capfile_name);
170 last_pathsep = strrchr(save_file, G_DIR_SEPARATOR);
171 pfx = strrchr(save_file,'.');
172 if (pfx != NULL && (last_pathsep == NULL || pfx > last_pathsep)) {
173 /* The pathname has a "." in it, and it's in the last component
174 of the pathname (because there is either only one component,
175 i.e. last_pathsep is null as there are no path separators,
176 or the "." is after the path separator before the last
179 Treat it as a separator between the rest of the file name and
180 the file name suffix, and arrange that the names given to the
181 ring buffer files have the specified suffix, i.e. put the
182 changing part of the name *before* the suffix. */
184 rb_data.fprefix = g_strdup(save_file);
185 pfx[0] = '.'; /* restore capfile_name */
186 rb_data.fsuffix = g_strdup(pfx);
188 /* Either there's no "." in the pathname, or it's in a directory
189 component, so the last component has no suffix. */
190 rb_data.fprefix = g_strdup(save_file);
191 rb_data.fsuffix = NULL;
196 /* allocate rb_file structures (only one if unlimited since there is no
197 need to save all file names in that case) */
199 if (num_files == RINGBUFFER_UNLIMITED_FILES) {
200 rb_data.unlimited = TRUE;
201 rb_data.num_files = 1;
204 rb_data.files = (rb_file *)g_malloc(rb_data.num_files * sizeof(rb_file));
205 if (rb_data.files == NULL) {
209 for (i=0; i < rb_data.num_files; i++) {
210 rb_data.files[i].name = NULL;
213 /* create the first file */
214 if (ringbuf_open_file(&rb_data.files[0], NULL) == -1) {
215 ringbuf_error_cleanup();
223 const gchar *ringbuf_current_filename(void)
225 return rb_data.files[rb_data.curr_file_num % rb_data.num_files].name;
229 * Calls libpcap_fdopen() for the current ringbuffer file
232 ringbuf_init_libpcap_fdopen(int *err)
234 rb_data.pdh = libpcap_fdopen(rb_data.fd, err);
239 * Switches to the next ringbuffer file
242 ringbuf_switch_file(FILE **pdh, gchar **save_file, int *save_file_fd, int *err)
245 rb_file *next_rfile = NULL;
247 /* close current file */
249 if (!libpcap_dump_close(rb_data.pdh, err)) {
250 ws_close(rb_data.fd); /* XXX - the above should have closed this already */
251 rb_data.pdh = NULL; /* it's still closed, we just got an error while closing */
259 /* get the next file number and open it */
261 rb_data.curr_file_num++ /* = next_file_num*/;
262 next_file_index = (rb_data.curr_file_num) % rb_data.num_files;
263 next_rfile = &rb_data.files[next_file_index];
265 if (ringbuf_open_file(next_rfile, err) == -1) {
269 if (ringbuf_init_libpcap_fdopen(err) == NULL) {
273 /* switch to the new file */
274 *save_file = next_rfile->name;
275 *save_file_fd = rb_data.fd;
276 (*pdh) = rb_data.pdh;
282 * Calls libpcap_dump_close() for the current ringbuffer file
285 ringbuf_libpcap_dump_close(gchar **save_file, int *err)
287 gboolean ret_val = TRUE;
289 /* close current file, if it's open */
290 if (rb_data.pdh != NULL) {
291 if (!libpcap_dump_close(rb_data.pdh, err)) {
292 ws_close(rb_data.fd);
300 /* set the save file name to the current file */
301 *save_file = rb_data.files[rb_data.curr_file_num % rb_data.num_files].name;
306 * Frees all memory allocated by the ringbuffer
313 if (rb_data.files != NULL) {
314 for (i=0; i < rb_data.num_files; i++) {
315 if (rb_data.files[i].name != NULL) {
316 g_free(rb_data.files[i].name);
317 rb_data.files[i].name = NULL;
320 g_free(rb_data.files);
321 rb_data.files = NULL;
323 if (rb_data.fprefix != NULL) {
324 g_free(rb_data.fprefix);
325 rb_data.fprefix = NULL;
327 if (rb_data.fsuffix != NULL) {
328 g_free(rb_data.fsuffix);
329 rb_data.fsuffix = NULL;
334 * Frees all memory allocated by the ringbuffer
337 ringbuf_error_cleanup(void)
341 /* try to close via wtap */
342 if (rb_data.pdh != NULL) {
343 if (libpcap_dump_close(rb_data.pdh, NULL)) {
349 /* close directly if still open */
350 /* XXX - it shouldn't still be open; "libpcap_dump_close()" should leave the
351 file closed even if it fails */
352 if (rb_data.fd != -1) {
353 ws_close(rb_data.fd);
357 if (rb_data.files != NULL) {
358 for (i=0; i < rb_data.num_files; i++) {
359 if (rb_data.files[i].name != NULL) {
360 ws_unlink(rb_data.files[i].name);
364 /* free the memory */
368 #endif /* HAVE_LIBPCAP */