2 * Routines for capture options setting
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
38 #ifdef HAVE_SYS_TYPES_H
39 # include <sys/types.h>
42 #ifdef HAVE_NETINET_IN_H
43 #include <netinet/in.h>
46 #ifdef HAVE_ARPA_INET_H
47 #include <arpa/inet.h>
50 #ifdef HAVE_SYS_SOCKET_H
51 #include <sys/socket.h> /* needed to define AF_ values on UNIX */
54 #ifdef HAVE_WINSOCK2_H
55 #include <winsock2.h> /* needed to define AF_ values on Windows */
58 #ifdef NEED_INET_V6DEFS_H
59 # include "inet_v6defs.h"
64 #include <epan/packet.h>
66 #include "capture_opts.h"
67 #include "ringbuffer.h"
68 #include "clopts_common.h"
69 #include "cmdarg_err.h"
71 #include "capture_ifinfo.h"
72 #include "capture-pcap-util.h"
73 #include <wsutil/file_util.h>
75 static gboolean capture_opts_output_to_pipe(const char *save_file, gboolean *is_pipe);
79 capture_opts_init(capture_options *capture_opts, void *cf)
81 capture_opts->cf = cf;
82 capture_opts->cfilter = g_strdup(""); /* No capture filter string specified */
83 capture_opts->iface = NULL; /* Default is "pick the first interface" */
84 capture_opts->iface_descr = NULL;
85 #ifdef HAVE_PCAP_REMOTE
86 capture_opts->src_type = CAPTURE_IFLOCAL;
87 capture_opts->remote_host = NULL;
88 capture_opts->remote_port = NULL;
89 capture_opts->auth_type = CAPTURE_AUTH_NULL;
90 capture_opts->auth_username = NULL;
91 capture_opts->auth_password = NULL;
92 capture_opts->datatx_udp = FALSE;
93 capture_opts->nocap_rpcap = TRUE;
94 capture_opts->nocap_local = FALSE;
95 #ifdef HAVE_PCAP_SETSAMPLING
96 capture_opts->sampling_method = CAPTURE_SAMP_NONE;
97 capture_opts->sampling_param = 0;
101 capture_opts->buffer_size = 1; /* 1 MB */
103 capture_opts->has_snaplen = FALSE;
104 capture_opts->snaplen = WTAP_MAX_PACKET_SIZE; /* snapshot length - default is
105 infinite, in effect */
106 capture_opts->promisc_mode = TRUE; /* promiscuous mode is the default */
107 capture_opts->linktype = -1; /* the default linktype */
108 capture_opts->saving_to_file = FALSE;
109 capture_opts->save_file = NULL;
110 capture_opts->use_pcapng = FALSE; /* the default is pcap */
111 capture_opts->real_time_mode = TRUE;
112 capture_opts->show_info = TRUE;
113 capture_opts->quit_after_cap = FALSE;
114 capture_opts->restart = FALSE;
116 capture_opts->multi_files_on = FALSE;
117 capture_opts->has_file_duration = FALSE;
118 capture_opts->file_duration = 60; /* 1 min */
119 capture_opts->has_ring_num_files = FALSE;
120 capture_opts->ring_num_files = RINGBUFFER_MIN_NUM_FILES;
122 capture_opts->has_autostop_files = FALSE;
123 capture_opts->autostop_files = 1;
124 capture_opts->has_autostop_packets = FALSE;
125 capture_opts->autostop_packets = 0;
126 capture_opts->has_autostop_filesize = FALSE;
127 capture_opts->autostop_filesize = 1024; /* 1 MB */
128 capture_opts->has_autostop_duration = FALSE;
129 capture_opts->autostop_duration = 60; /* 1 min */
132 capture_opts->fork_child = -1; /* invalid process handle */
134 capture_opts->signal_pipe_write_fd = -1;
136 capture_opts->state = CAPTURE_STOPPED;
137 capture_opts->output_to_pipe = FALSE;
139 capture_opts->owner = getuid();
140 capture_opts->group = getgid();
145 /* log content of capture_opts */
147 capture_opts_log(const char *log_domain, GLogLevelFlags log_level, capture_options *capture_opts) {
148 g_log(log_domain, log_level, "CAPTURE OPTIONS :");
149 g_log(log_domain, log_level, "CFile : 0x%p", capture_opts->cf);
150 g_log(log_domain, log_level, "Filter : %s", capture_opts->cfilter);
151 g_log(log_domain, log_level, "Interface : %s", capture_opts->iface);
152 /* iface_descr may not been filled in and some C Libraries hate a null ptr for %s */
153 g_log(log_domain, log_level, "Interface Descr : %s",
154 capture_opts->iface_descr ? capture_opts->iface_descr : "<null>");
155 #ifdef HAVE_PCAP_REMOTE
156 g_log(log_domain, log_level, "Capture source : %s",
157 capture_opts->src_type == CAPTURE_IFLOCAL ? "Local interface" :
158 capture_opts->src_type == CAPTURE_IFREMOTE ? "Remote interface" :
160 if (capture_opts->src_type == CAPTURE_IFREMOTE) {
161 g_log(log_domain, log_level, "Remote host : %s", capture_opts->remote_host);
162 g_log(log_domain, log_level, "Remote port : %s", capture_opts->remote_port);
164 g_log(log_domain, log_level, "Authentication : %s",
165 capture_opts->auth_type == CAPTURE_AUTH_NULL ? "Null" :
166 capture_opts->auth_type == CAPTURE_AUTH_PWD ? "By username/password" :
168 if (capture_opts->auth_type == CAPTURE_AUTH_PWD) {
169 g_log(log_domain, log_level, "Auth username : %s", capture_opts->auth_password);
170 g_log(log_domain, log_level, "Auth password : <hidden>");
172 g_log(log_domain, log_level, "UDP data transfer : %u", capture_opts->datatx_udp);
173 g_log(log_domain, log_level, "No capture RPCAP : %u", capture_opts->nocap_rpcap);
174 g_log(log_domain, log_level, "No capture local : %u", capture_opts->nocap_local);
177 g_log(log_domain, log_level, "BufferSize : %u (MB)", capture_opts->buffer_size);
179 g_log(log_domain, log_level, "SnapLen (%u): %u", capture_opts->has_snaplen, capture_opts->snaplen);
180 g_log(log_domain, log_level, "Promisc : %u", capture_opts->promisc_mode);
181 g_log(log_domain, log_level, "LinkType : %d", capture_opts->linktype);
182 g_log(log_domain, log_level, "SavingToFile : %u", capture_opts->saving_to_file);
183 g_log(log_domain, log_level, "SaveFile : %s", (capture_opts->save_file) ? capture_opts->save_file : "");
184 g_log(log_domain, log_level, "Fileformat : %s", (capture_opts->use_pcapng) ? "PCAPNG" : "PCAP");
185 g_log(log_domain, log_level, "RealTimeMode : %u", capture_opts->real_time_mode);
186 g_log(log_domain, log_level, "ShowInfo : %u", capture_opts->show_info);
187 g_log(log_domain, log_level, "QuitAfterCap : %u", capture_opts->quit_after_cap);
189 g_log(log_domain, log_level, "MultiFilesOn : %u", capture_opts->multi_files_on);
190 g_log(log_domain, log_level, "FileDuration (%u): %u", capture_opts->has_file_duration, capture_opts->file_duration);
191 g_log(log_domain, log_level, "RingNumFiles (%u): %u", capture_opts->has_ring_num_files, capture_opts->ring_num_files);
193 g_log(log_domain, log_level, "AutostopFiles (%u): %u", capture_opts->has_autostop_files, capture_opts->autostop_files);
194 g_log(log_domain, log_level, "AutostopPackets (%u): %u", capture_opts->has_autostop_packets, capture_opts->autostop_packets);
195 g_log(log_domain, log_level, "AutostopFilesize(%u): %u (KB)", capture_opts->has_autostop_filesize, capture_opts->autostop_filesize);
196 g_log(log_domain, log_level, "AutostopDuration(%u): %u", capture_opts->has_autostop_duration, capture_opts->autostop_duration);
198 g_log(log_domain, log_level, "ForkChild : %d", capture_opts->fork_child);
200 g_log(log_domain, log_level, "SignalPipeWrite : %d", capture_opts->signal_pipe_write_fd);
205 * Given a string of the form "<autostop criterion>:<value>", as might appear
206 * as an argument to a "-a" option, parse it and set the criterion in
207 * question. Return an indication of whether it succeeded or failed
211 set_autostop_criterion(capture_options *capture_opts, const char *autostoparg)
215 colonp = strchr(autostoparg, ':');
223 * Skip over any white space (there probably won't be any, but
224 * as we allow it in the preferences file, we might as well
227 while (isspace((guchar)*p))
231 * Put the colon back, so if our caller uses, in an
232 * error message, the string they passed us, the message
238 if (strcmp(autostoparg,"duration") == 0) {
239 capture_opts->has_autostop_duration = TRUE;
240 capture_opts->autostop_duration = get_positive_int(p,"autostop duration");
241 } else if (strcmp(autostoparg,"filesize") == 0) {
242 capture_opts->has_autostop_filesize = TRUE;
243 capture_opts->autostop_filesize = get_positive_int(p,"autostop filesize");
244 } else if (strcmp(autostoparg,"files") == 0) {
245 capture_opts->multi_files_on = TRUE;
246 capture_opts->has_autostop_files = TRUE;
247 capture_opts->autostop_files = get_positive_int(p,"autostop files");
251 *colonp = ':'; /* put the colon back */
256 * Given a string of the form "<ring buffer file>:<duration>", as might appear
257 * as an argument to a "-b" option, parse it and set the arguments in
258 * question. Return an indication of whether it succeeded or failed
262 get_ring_arguments(capture_options *capture_opts, const char *arg)
264 gchar *p = NULL, *colonp;
266 colonp = strchr(arg, ':');
274 * Skip over any white space (there probably won't be any, but
275 * as we allow it in the preferences file, we might as well
278 while (isspace((guchar)*p))
282 * Put the colon back, so if our caller uses, in an
283 * error message, the string they passed us, the message
290 if (strcmp(arg,"files") == 0) {
291 capture_opts->has_ring_num_files = TRUE;
292 capture_opts->ring_num_files = get_natural_int(p, "number of ring buffer files");
293 } else if (strcmp(arg,"filesize") == 0) {
294 capture_opts->has_autostop_filesize = TRUE;
295 capture_opts->autostop_filesize = get_positive_int(p, "ring buffer filesize");
296 } else if (strcmp(arg,"duration") == 0) {
297 capture_opts->has_file_duration = TRUE;
298 capture_opts->file_duration = get_positive_int(p, "ring buffer duration");
301 *colonp = ':'; /* put the colon back */
305 #ifdef HAVE_PCAP_SETSAMPLING
307 * Given a string of the form "<sampling type>:<value>", as might appear
308 * as an argument to a "-m" option, parse it and set the arguments in
309 * question. Return an indication of whether it succeeded or failed
313 get_sampling_arguments(capture_options *capture_opts, const char *arg)
315 gchar *p = NULL, *colonp;
317 colonp = strchr(arg, ':');
324 while (isspace((guchar)*p))
331 if (strcmp(arg, "count") == 0) {
332 capture_opts->sampling_method = CAPTURE_SAMP_BY_COUNT;
333 capture_opts->sampling_param = get_positive_int(p, "sampling count");
334 } else if (strcmp(arg, "timer") == 0) {
335 capture_opts->sampling_method = CAPTURE_SAMP_BY_TIMER;
336 capture_opts->sampling_param = get_positive_int(p, "sampling timer");
343 #ifdef HAVE_PCAP_REMOTE
345 * Given a string of the form "<username>:<password>", as might appear
346 * as an argument to a "-A" option, parse it and set the arguments in
347 * question. Return an indication of whether it succeeded or failed
351 get_auth_arguments(capture_options *capture_opts, const char *arg)
353 gchar *p = NULL, *colonp;
355 colonp = strchr(arg, ':');
362 while (isspace((guchar)*p))
365 capture_opts->auth_type = CAPTURE_AUTH_PWD;
366 capture_opts->auth_username = g_strdup(arg);
367 capture_opts->auth_password = g_strdup(p);
374 capture_opts_add_iface_opt(capture_options *capture_opts, const char *optarg_str_p)
385 * If the argument is a number, treat it as an index into the list
386 * of adapters, as printed by "tshark -D".
388 * This should be OK on UNIX systems, as interfaces shouldn't have
389 * names that begin with digits. It can be useful on Windows, where
390 * more than one interface can have the same name.
392 adapter_index = strtol(optarg_str_p, &p, 10);
393 if (p != NULL && *p == '\0') {
394 if (adapter_index < 0) {
395 cmdarg_err("The specified adapter index is a negative number");
398 if (adapter_index > INT_MAX) {
399 cmdarg_err("The specified adapter index is too large (greater than %d)",
403 if (adapter_index == 0) {
404 cmdarg_err("There is no interface with that adapter index");
407 if_list = capture_interface_list(&err, &err_str);
408 if (if_list == NULL) {
411 case CANT_GET_INTERFACE_LIST:
412 cmdarg_err("%s", err_str);
416 case NO_INTERFACES_FOUND:
417 cmdarg_err("There are no interfaces on which a capture can be done");
422 if_info = (if_info_t *)g_list_nth_data(if_list, adapter_index - 1);
423 if (if_info == NULL) {
424 cmdarg_err("There is no interface with that adapter index");
427 capture_opts->iface = g_strdup(if_info->name);
428 /* We don't set iface_descr here because doing so requires
429 * capture_ui_utils.c which requires epan/prefs.c which is
430 * probably a bit too much dependency for here...
432 free_interface_list(if_list);
434 capture_opts->iface = g_strdup(optarg_str_p);
441 capture_opts_add_opt(capture_options *capture_opts, int opt, const char *optarg_str_p, gboolean *start_capture)
446 case 'a': /* autostop criteria */
447 if (set_autostop_criterion(capture_opts, optarg_str_p) == FALSE) {
448 cmdarg_err("Invalid or unknown -a flag \"%s\"", optarg_str_p);
452 #ifdef HAVE_PCAP_REMOTE
454 if (get_auth_arguments(capture_opts, optarg_str_p) == FALSE) {
455 cmdarg_err("Invalid or unknown -A arg \"%s\"", optarg_str_p);
460 case 'b': /* Ringbuffer option */
461 capture_opts->multi_files_on = TRUE;
462 if (get_ring_arguments(capture_opts, optarg_str_p) == FALSE) {
463 cmdarg_err("Invalid or unknown -b arg \"%s\"", optarg_str_p);
468 case 'B': /* Buffer size */
469 capture_opts->buffer_size = get_positive_int(optarg_str_p, "buffer size");
472 case 'c': /* Capture n packets */
473 capture_opts->has_autostop_packets = TRUE;
474 capture_opts->autostop_packets = get_positive_int(optarg_str_p, "packet count");
476 case 'f': /* capture filter */
477 if (capture_opts->has_cfilter) {
478 cmdarg_err("More than one -f argument specified");
481 capture_opts->has_cfilter = TRUE;
482 g_free(capture_opts->cfilter);
483 capture_opts->cfilter = g_strdup(optarg_str_p);
485 case 'H': /* Hide capture info dialog box */
486 capture_opts->show_info = FALSE;
488 case 'i': /* Use interface x */
489 status = capture_opts_add_iface_opt(capture_opts, optarg_str_p);
494 case 'k': /* Start capture immediately */
495 *start_capture = TRUE;
497 /*case 'l':*/ /* Automatic scrolling in live capture mode */
498 #ifdef HAVE_PCAP_SETSAMPLING
500 if (get_sampling_arguments(capture_opts, optarg_str_p) == FALSE) {
501 cmdarg_err("Invalid or unknown -m arg \"%s\"", optarg_str_p);
506 case 'n': /* Use pcapng format */
507 capture_opts->use_pcapng = TRUE;
509 case 'p': /* Don't capture in promiscuous mode */
510 capture_opts->promisc_mode = FALSE;
512 case 'Q': /* Quit after capture (just capture to file) */
513 capture_opts->quit_after_cap = TRUE;
514 *start_capture = TRUE; /*** -Q implies -k !! ***/
516 #ifdef HAVE_PCAP_REMOTE
518 capture_opts->nocap_rpcap = FALSE;
521 case 's': /* Set the snapshot (capture) length */
522 capture_opts->has_snaplen = TRUE;
523 capture_opts->snaplen = get_natural_int(optarg_str_p, "snapshot length");
525 * Make a snapshot length of 0 equivalent to the maximum packet
526 * length, mirroring what tcpdump does.
528 if (capture_opts->snaplen == 0)
529 capture_opts->snaplen = WTAP_MAX_PACKET_SIZE;
531 case 'S': /* "Real-Time" mode: used for following file ala tail -f */
532 capture_opts->real_time_mode = TRUE;
534 #ifdef HAVE_PCAP_REMOTE
536 capture_opts->datatx_udp = TRUE;
539 case 'w': /* Write to capture file x */
540 capture_opts->saving_to_file = TRUE;
541 g_free(capture_opts->save_file);
542 #if defined _WIN32 && GLIB_CHECK_VERSION(2,6,0)
543 /* since GLib 2.6, we need to convert filenames to utf8 for Win32 */
544 capture_opts->save_file = g_locale_to_utf8(optarg_str_p, -1, NULL, NULL, NULL);
546 capture_opts->save_file = g_strdup(optarg_str_p);
548 status = capture_opts_output_to_pipe(capture_opts->save_file, &capture_opts->output_to_pipe);
550 case 'y': /* Set the pcap data link type */
551 capture_opts->linktype = linktype_name_to_val(optarg_str_p);
552 if (capture_opts->linktype == -1) {
553 cmdarg_err("The specified data link type \"%s\" isn't valid",
559 /* the caller is responsible to send us only the right opt's */
560 g_assert_not_reached();
567 * If you change the output format of this function, you MUST update
568 * capture_sync.c:sync_linktype_list_open() accordingly!
571 capture_opts_list_link_layer_types(capture_options *capture_opts, gboolean machine_readable)
574 const gchar *desc_str;
575 GList *lt_list, *lt_entry;
576 data_link_info_t *data_link_info;
578 /* Get the list of link-layer types for the capture device. */
579 lt_list = get_pcap_linktype_list(capture_opts->iface, &err_str);
580 if (lt_list == NULL) {
581 if (err_str != NULL) {
582 cmdarg_err("The list of data link types for the capture device \"%s\" could not be obtained (%s)."
583 "Please check to make sure you have sufficient permissions, and that\n"
584 "you have the proper interface or pipe specified.\n", capture_opts->iface, err_str);
587 cmdarg_err("The capture device \"%s\" has no data link types.", capture_opts->iface);
590 if (machine_readable) { /* tab-separated values to stdout */
591 for (lt_entry = lt_list; lt_entry != NULL; lt_entry = g_list_next(lt_entry)) {
592 data_link_info = (data_link_info_t *)lt_entry->data;
593 if (data_link_info->description != NULL)
594 desc_str = data_link_info->description;
596 desc_str = "(not supported)";
597 printf("%d\t%s\t%s\n", data_link_info->dlt, data_link_info->name,
601 cmdarg_err_cont("Data link types (use option -y to set):");
602 for (lt_entry = lt_list; lt_entry != NULL;
603 lt_entry = g_list_next(lt_entry)) {
604 data_link_info = (data_link_info_t *)lt_entry->data;
605 cmdarg_err_cont(" %s", data_link_info->name);
606 if (data_link_info->description != NULL)
607 cmdarg_err_cont(" (%s)", data_link_info->description);
609 cmdarg_err_cont(" (not supported)");
613 free_pcap_linktype_list(lt_list);
618 /* Return an ASCII-formatted list of interfaces. */
619 #define ADDRSTRLEN 46 /* Covers IPv4 & IPv6 */
621 capture_opts_list_interfaces(gboolean machine_readable)
631 char addr_str[ADDRSTRLEN];
633 if_list = capture_interface_list(&err, &err_str);
634 if (if_list == NULL) {
636 case CANT_GET_INTERFACE_LIST:
637 cmdarg_err("%s", err_str);
641 case NO_INTERFACES_FOUND:
642 cmdarg_err("There are no interfaces on which a capture can be done");
648 i = 1; /* Interface id number */
649 for (if_entry = g_list_first(if_list); if_entry != NULL;
650 if_entry = g_list_next(if_entry)) {
651 if_info = (if_info_t *)if_entry->data;
652 printf("%d. %s", i++, if_info->name);
654 if (!machine_readable) {
655 /* Add the description if it exists */
656 if (if_info->description != NULL)
657 printf(" (%s)", if_info->description);
660 * Add the contents of the if_entry struct in a parseable format.
661 * Each if_entry element is tab-separated. Addresses are comma-
664 /* XXX - Make sure our description doesn't contain a tab */
665 if (if_info->description != NULL)
666 printf("\t%s\t", if_info->description);
670 for(addr = g_slist_nth(if_info->addrs, 0); addr != NULL;
671 addr = g_slist_next(addr)) {
672 if (addr != g_slist_nth(if_info->addrs, 0))
675 if_addr = (if_addr_t *)addr->data;
676 switch(if_addr->ifat_type) {
678 if (inet_ntop(AF_INET, &if_addr->addr.ip4_addr, addr_str,
680 printf("%s", addr_str);
682 printf("<unknown IPv4>");
686 if (inet_ntop(AF_INET6, &if_addr->addr.ip6_addr,
687 addr_str, ADDRSTRLEN)) {
688 printf("%s", addr_str);
690 printf("<unknown IPv6>");
694 printf("<type unknown %u>", if_addr->ifat_type);
698 if (if_info->loopback)
699 printf("\tloopback");
706 free_interface_list(if_list);
712 void capture_opts_trim_snaplen(capture_options *capture_opts, int snaplen_min)
714 if (capture_opts->snaplen < 1)
715 capture_opts->snaplen = WTAP_MAX_PACKET_SIZE;
716 else if (capture_opts->snaplen < snaplen_min)
717 capture_opts->snaplen = snaplen_min;
721 void capture_opts_trim_ring_num_files(capture_options *capture_opts)
723 /* Check the value range of the ring_num_files parameter */
724 if (capture_opts->ring_num_files > RINGBUFFER_MAX_NUM_FILES)
725 capture_opts->ring_num_files = RINGBUFFER_MAX_NUM_FILES;
726 #if RINGBUFFER_MIN_NUM_FILES > 0
727 else if (capture_opts->ring_num_files < RINGBUFFER_MIN_NUM_FILES)
728 capture_opts->ring_num_files = RINGBUFFER_MIN_NUM_FILES;
733 gboolean capture_opts_trim_iface(capture_options *capture_opts, const char *capture_device)
741 /* Did the user specify an interface to use? */
742 if (capture_opts->iface == NULL) {
743 /* No - is a default specified in the preferences file? */
744 if (capture_device != NULL) {
746 capture_opts->iface = g_strdup(capture_device);
747 /* We don't set iface_descr here because doing so requires
748 * capture_ui_utils.c which requires epan/prefs.c which is
749 * probably a bit too much dependency for here...
752 /* No - pick the first one from the list of interfaces. */
753 if_list = capture_interface_list(&err, &err_str);
754 if (if_list == NULL) {
757 case CANT_GET_INTERFACE_LIST:
758 cmdarg_err("%s", err_str);
762 case NO_INTERFACES_FOUND:
763 cmdarg_err("There are no interfaces on which a capture can be done");
768 if_info = (if_info_t *)if_list->data; /* first interface */
769 capture_opts->iface = g_strdup(if_info->name);
770 /* We don't set iface_descr here because doing so requires
771 * capture_ui_utils.c which requires epan/prefs.c which is
772 * probably a bit too much dependency for here...
774 free_interface_list(if_list);
784 #define S_IFIFO _S_IFIFO
787 #define S_ISFIFO(mode) (((mode) & S_IFMT) == S_IFIFO)
790 /* copied from filesystem.c */
791 static int capture_opts_test_for_fifo(const char *path)
795 if (ws_stat(path, &statb) < 0)
798 if (S_ISFIFO(statb.st_mode))
804 static gboolean capture_opts_output_to_pipe(const char *save_file, gboolean *is_pipe)
810 if (save_file != NULL) {
811 /* We're writing to a capture file. */
812 if (strcmp(save_file, "-") == 0) {
813 /* Writing to stdout. */
814 /* XXX - should we check whether it's a pipe? It's arguably
815 silly to do "-w - >output_file" rather than "-w output_file",
816 but by not checking we might be violating the Principle Of
817 Least Astonishment. */
820 /* not writing to stdout, test for a FIFO (aka named pipe) */
821 err = capture_opts_test_for_fifo(save_file);
824 case ENOENT: /* it doesn't exist, so we'll be creating it,
825 and it won't be a FIFO */
826 case 0: /* found it, but it's not a FIFO */
829 case ESPIPE: /* it is a FIFO */
833 default: /* couldn't stat it */
834 break; /* ignore: later attempt to open */
835 /* will generate a nice msg */
843 #endif /* HAVE_LIBPCAP */