2 * Routines for packet capture windows
6 * Ethereal - Network traffic analyzer
7 * By Gerald Combs <gerald@ethereal.com>
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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).
69 #include "ringbuffer.h"
70 #include "file_util.h"
73 /* Ringbuffer file structure */
74 typedef struct _rb_file {
78 /* Ringbuffer data structure */
79 typedef struct _ringbuf_data {
81 guint num_files; /* Number of ringbuffer files (1 to ...) */
82 guint curr_file_num; /* Number of the current file (ever increasing) */
83 gchar *fprefix; /* Filename prefix */
84 gchar *fsuffix; /* Filename suffix */
85 gboolean unlimited; /* TRUE if unlimited number of files */
89 int fd; /* Current ringbuffer file descriptor */
91 long bytes_written; /* Bytes written to the current file */
94 static ringbuf_data rb_data;
98 * create the next filename and open a new binary file with that name
100 static int ringbuf_open_file(rb_file *rfile, int *err)
106 if (rfile->name != NULL) {
107 if (rb_data.unlimited == FALSE) {
108 /* remove old file (if any, so ignore error) */
109 eth_unlink(rfile->name);
117 current_time = time(NULL);
119 g_snprintf(filenum, sizeof(filenum), "%05d", rb_data.curr_file_num + 1 /*.number*/);
120 strftime(timestr, sizeof(timestr), "%Y%m%d%H%M%S", localtime(¤t_time));
121 rfile->name = g_strconcat(rb_data.fprefix, "_", filenum, "_", timestr,
122 rb_data.fsuffix, NULL);
124 if (rfile->name == NULL) {
129 rb_data.fd = eth_open(rfile->name, O_RDWR|O_BINARY|O_TRUNC|O_CREAT, 0600);
131 if (rb_data.fd == -1 && err != NULL) {
139 * Initialize the ringbuffer data structures
142 ringbuf_init(const char *capfile_name, guint num_files)
145 char *pfx, *last_pathsep;
148 rb_data.files = NULL;
149 rb_data.curr_file_num = 0;
150 rb_data.fprefix = NULL;
151 rb_data.fsuffix = NULL;
152 rb_data.unlimited = FALSE;
156 /* just to be sure ... */
157 if (num_files <= RINGBUFFER_MAX_NUM_FILES) {
158 rb_data.num_files = num_files;
160 rb_data.num_files = RINGBUFFER_MAX_NUM_FILES;
163 /* Check file name */
164 if (capfile_name == NULL) {
165 /* ringbuffer does not work with temporary files! */
169 /* set file name prefix/suffix */
171 save_file = g_strdup(capfile_name);
172 last_pathsep = strrchr(save_file, G_DIR_SEPARATOR);
173 pfx = strrchr(save_file,'.');
174 if (pfx != NULL && (last_pathsep == NULL || pfx > last_pathsep)) {
175 /* The pathname has a "." in it, and it's in the last component
176 of the pathname (because there is either only one component,
177 i.e. last_pathsep is null as there are no path separators,
178 or the "." is after the path separator before the last
181 Treat it as a separator between the rest of the file name and
182 the file name suffix, and arrange that the names given to the
183 ring buffer files have the specified suffix, i.e. put the
184 changing part of the name *before* the suffix. */
186 rb_data.fprefix = g_strdup(save_file);
187 pfx[0] = '.'; /* restore capfile_name */
188 rb_data.fsuffix = g_strdup(pfx);
190 /* Either there's no "." in the pathname, or it's in a directory
191 component, so the last component has no suffix. */
192 rb_data.fprefix = g_strdup(save_file);
193 rb_data.fsuffix = NULL;
198 /* allocate rb_file structures (only one if unlimited since there is no
199 need to save all file names in that case) */
201 if (num_files == RINGBUFFER_UNLIMITED_FILES) {
202 rb_data.unlimited = TRUE;
203 rb_data.num_files = 1;
206 rb_data.files = g_malloc(rb_data.num_files * sizeof(rb_file));
207 if (rb_data.files == NULL) {
211 for (i=0; i < rb_data.num_files; i++) {
212 rb_data.files[i].name = NULL;
215 /* create the first file */
216 if (ringbuf_open_file(&rb_data.files[0], NULL) == -1) {
217 ringbuf_error_cleanup();
225 const gchar *ringbuf_current_filename(void)
227 return rb_data.files[rb_data.curr_file_num % rb_data.num_files].name;
231 * Calls libpcap_fdopen() for the current ringbuffer file
234 ringbuf_init_libpcap_fdopen(int linktype, int snaplen, int *err)
237 rb_data.linktype = linktype;
238 rb_data.snaplen = snaplen;
240 rb_data.pdh = libpcap_fdopen(rb_data.fd, linktype, snaplen,
241 &rb_data.bytes_written, err);
246 * Switches to the next ringbuffer file
249 ringbuf_switch_file(FILE **pdh, gchar **save_file, int *save_file_fd, int *err)
252 rb_file *next_rfile = NULL;
254 /* close current file */
256 if (!libpcap_dump_close(rb_data.pdh, err)) {
257 eth_close(rb_data.fd); /* XXX - the above should have closed this already */
258 rb_data.pdh = NULL; /* it's still closed, we just got an error while closing */
266 /* get the next file number and open it */
268 rb_data.curr_file_num++ /* = next_file_num*/;
269 next_file_num = (rb_data.curr_file_num) % rb_data.num_files;
270 next_rfile = &rb_data.files[next_file_num];
272 if (ringbuf_open_file(next_rfile, err) == -1) {
276 if (ringbuf_init_libpcap_fdopen(rb_data.linktype, rb_data.snaplen,
281 /* switch to the new file */
282 *save_file = next_rfile->name;
283 *save_file_fd = rb_data.fd;
284 (*pdh) = rb_data.pdh;
290 * Calls libpcap_dump_close() for the current ringbuffer file
293 ringbuf_libpcap_dump_close(gchar **save_file, int *err)
295 gboolean ret_val = TRUE;
297 /* close current file, if it's open */
298 if (rb_data.pdh != NULL) {
299 if (!libpcap_dump_close(rb_data.pdh, err)) {
300 eth_close(rb_data.fd);
308 /* set the save file name to the current file */
309 *save_file = rb_data.files[rb_data.curr_file_num % rb_data.num_files].name;
314 * Frees all memory allocated by the ringbuffer
321 if (rb_data.files != NULL) {
322 for (i=0; i < rb_data.num_files; i++) {
323 if (rb_data.files[i].name != NULL) {
324 g_free(rb_data.files[i].name);
325 rb_data.files[i].name = NULL;
328 g_free(rb_data.files);
329 rb_data.files = NULL;
331 if (rb_data.fprefix != NULL) {
332 g_free(rb_data.fprefix);
333 rb_data.fprefix = NULL;
335 if (rb_data.fsuffix != NULL) {
336 g_free(rb_data.fsuffix);
337 rb_data.fsuffix = NULL;
342 * Frees all memory allocated by the ringbuffer
345 ringbuf_error_cleanup(void)
349 /* try to close via wtap */
350 if (rb_data.pdh != NULL) {
351 if (libpcap_dump_close(rb_data.pdh, NULL)) {
357 /* close directly if still open */
358 /* XXX - it shouldn't still be open; "libpcap_dump_close()" should leave the
359 file closed even if it fails */
360 if (rb_data.fd != -1) {
361 eth_close(rb_data.fd);
365 if (rb_data.files != NULL) {
366 for (i=0; i < rb_data.num_files; i++) {
367 if (rb_data.files[i].name != NULL) {
368 eth_unlink(rb_data.files[i].name);
372 /* free the memory */
376 #endif /* HAVE_LIBPCAP */