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Erik Andersene49d5ec2000-02-08 19:58:47 +00001/* vi: set sw=4 ts=4: */
Erik Andersen7ab9c7e2000-05-12 19:41:47 +00002/* nc: mini-netcat - built from the ground up for LRP
Denis Vlasenko9213a9e2006-09-17 16:28:10 +00003 *
Rob Landley1cca9482006-07-10 19:45:20 +00004 * Copyright (C) 1998, 1999 Charles P. Wright
5 * Copyright (C) 1998 Dave Cinege
Denis Vlasenko9213a9e2006-09-17 16:28:10 +00006 *
Rob Landley1cca9482006-07-10 19:45:20 +00007 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8 */
Eric Andersencc8ed391999-10-05 16:24:54 +00009
Denis Vlasenkob6adbf12007-05-26 19:00:18 +000010#include "libbb.h"
Eric Andersencc8ed391999-10-05 16:24:54 +000011
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020012//config:config NC
13//config: bool "nc"
14//config: default y
15//config: help
16//config: A simple Unix utility which reads and writes data across network
17//config: connections.
18//config:
19//config:config NC_SERVER
20//config: bool "Netcat server options (-l)"
21//config: default y
22//config: depends on NC
23//config: help
24//config: Allow netcat to act as a server.
25//config:
26//config:config NC_EXTRA
27//config: bool "Netcat extensions (-eiw and filename)"
28//config: default y
29//config: depends on NC
30//config: help
31//config: Add -e (support for executing the rest of the command line after
32//config: making or receiving a successful connection), -i (delay interval for
33//config: lines sent), -w (timeout for initial connection).
34//config:
35//config:config NC_110_COMPAT
36//config: bool "Netcat 1.10 compatibility (+2.5k)"
37//config: default y
38//config: depends on NC
39//config: help
40//config: This option makes nc closely follow original nc-1.10.
41//config: The code is about 2.5k bigger. It enables
42//config: -s ADDR, -n, -u, -v, -o FILE, -z options, but loses
43//config: busybox-specific extensions: -f FILE and -ll.
44
45#if ENABLE_NC_110_COMPAT
46# include "nc_bloaty.c"
Denis Vlasenko29fe7262007-04-05 20:26:28 +000047#else
48
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020049//usage:#if !ENABLE_NC_110_COMPAT
50//usage:
51//usage:#if ENABLE_NC_SERVER || ENABLE_NC_EXTRA
52//usage:#define NC_OPTIONS_STR "\n\nOptions:"
53//usage:#else
54//usage:#define NC_OPTIONS_STR
55//usage:#endif
56//usage:
57//usage:#define nc_trivial_usage
58//usage: IF_NC_EXTRA("[-iN] [-wN] ")IF_NC_SERVER("[-l] [-p PORT] ")
59//usage: "["IF_NC_EXTRA("-f FILE|")"IPADDR PORT]"IF_NC_EXTRA(" [-e PROG]")
60//usage:#define nc_full_usage "\n\n"
61//usage: "Open a pipe to IP:PORT" IF_NC_EXTRA(" or FILE")
62//usage: NC_OPTIONS_STR
63//usage: IF_NC_EXTRA(
64//usage: "\n -e PROG Run PROG after connect"
65//usage: IF_NC_SERVER(
66//usage: "\n -l Listen mode, for inbound connects"
67//usage: IF_NC_EXTRA(
68//usage: "\n (use -l twice with -e for persistent server)")
69//usage: "\n -p PORT Local port"
70//usage: )
71//usage: "\n -w SEC Timeout for connect"
72//usage: "\n -i SEC Delay interval for lines sent"
73//usage: "\n -f FILE Use file (ala /dev/ttyS0) instead of network"
74//usage: )
75//usage:
76//usage:#define nc_notes_usage ""
77//usage: IF_NC_EXTRA(
78//usage: "To use netcat as a terminal emulator on a serial port:\n\n"
79//usage: "$ stty 115200 -F /dev/ttyS0\n"
80//usage: "$ stty raw -echo -ctlecho && nc -f /dev/ttyS0\n"
81//usage: )
82//usage:
83//usage:#define nc_example_usage
84//usage: "$ nc foobar.somedomain.com 25\n"
85//usage: "220 foobar ESMTP Exim 3.12 #1 Sat, 15 Apr 2000 00:03:02 -0600\n"
86//usage: "help\n"
87//usage: "214-Commands supported:\n"
88//usage: "214- HELO EHLO MAIL RCPT DATA AUTH\n"
89//usage: "214 NOOP QUIT RSET HELP\n"
90//usage: "quit\n"
91//usage: "221 foobar closing connection\n"
92//usage:
93//usage:#endif
94
Denis Vlasenko5d687242007-01-12 20:59:31 +000095/* Lots of small differences in features
96 * when compared to "standard" nc
97 */
98
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +000099static void timeout(int signum UNUSED_PARAM)
Mike Frysinger60a5c382005-05-06 04:45:38 +0000100{
Denis Vlasenko13858992006-10-08 12:49:22 +0000101 bb_error_msg_and_die("timed out");
Mike Frysinger60a5c382005-05-06 04:45:38 +0000102}
103
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +0000104int nc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Erik Andersen7ab9c7e2000-05-12 19:41:47 +0000105int nc_main(int argc, char **argv)
Eric Andersencc8ed391999-10-05 16:24:54 +0000106{
Denis Vlasenko5d687242007-01-12 20:59:31 +0000107 /* sfd sits _here_ only because of "repeat" option (-l -l). */
108 int sfd = sfd; /* for gcc */
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000109 int cfd = 0;
Denis Vlasenko31635552007-01-20 16:54:19 +0000110 unsigned lport = 0;
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000111 IF_NOT_NC_SERVER(const) unsigned do_listen = 0;
112 IF_NOT_NC_EXTRA (const) unsigned wsecs = 0;
113 IF_NOT_NC_EXTRA (const) unsigned delay = 0;
114 IF_NOT_NC_EXTRA (const int execparam = 0;)
115 IF_NC_EXTRA (char **execparam = NULL;)
Erik Andersene49d5ec2000-02-08 19:58:47 +0000116 fd_set readfds, testfds;
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000117 int opt; /* must be signed (getopt returns -1) */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000118
Denis Vlasenko9213a9e2006-09-17 16:28:10 +0000119 if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) {
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000120 /* getopt32 is _almost_ usable:
Denys Vlasenko77cc2c52010-06-27 04:22:02 +0200121 ** it cannot handle "... -e PROG -prog-opt" */
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000122 while ((opt = getopt(argc, argv,
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000123 "" IF_NC_SERVER("lp:") IF_NC_EXTRA("w:i:f:e:") )) > 0
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000124 ) {
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000125 if (ENABLE_NC_SERVER && opt == 'l')
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000126 IF_NC_SERVER(do_listen++);
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000127 else if (ENABLE_NC_SERVER && opt == 'p')
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000128 IF_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0));
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000129 else if (ENABLE_NC_EXTRA && opt == 'w')
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000130 IF_NC_EXTRA( wsecs = xatou(optarg));
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000131 else if (ENABLE_NC_EXTRA && opt == 'i')
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000132 IF_NC_EXTRA( delay = xatou(optarg));
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000133 else if (ENABLE_NC_EXTRA && opt == 'f')
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000134 IF_NC_EXTRA( cfd = xopen(optarg, O_RDWR));
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000135 else if (ENABLE_NC_EXTRA && opt == 'e' && optind <= argc) {
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000136 /* We cannot just 'break'. We should let getopt finish.
137 ** Or else we won't be able to find where
138 ** 'host' and 'port' params are
Denys Vlasenko77cc2c52010-06-27 04:22:02 +0200139 ** (think "nc -w 60 host port -e PROG"). */
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000140 IF_NC_EXTRA(
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000141 char **p;
142 // +2: one for progname (optarg) and one for NULL
143 execparam = xzalloc(sizeof(char*) * (argc - optind + 2));
144 p = execparam;
145 *p++ = optarg;
146 while (optind < argc) {
147 *p++ = argv[optind++];
148 }
149 )
150 /* optind points to argv[arvc] (NULL) now.
151 ** FIXME: we assume that getopt will not count options
Denys Vlasenko77cc2c52010-06-27 04:22:02 +0200152 ** possibly present on "-e PROG ARGS" and will not
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000153 ** include them into final value of optind
154 ** which is to be used ... */
Rob Landley1cca9482006-07-10 19:45:20 +0000155 } else bb_show_usage();
Matt Kraai1d702672001-02-07 04:09:23 +0000156 }
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000157 argv += optind; /* ... here! */
158 argc -= optind;
159 // -l and -f don't mix
160 if (do_listen && cfd) bb_show_usage();
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000161 // File mode needs need zero arguments, listen mode needs zero or one,
162 // client mode needs one or two
163 if (cfd) {
Denis Vlasenko5d687242007-01-12 20:59:31 +0000164 if (argc) bb_show_usage();
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000165 } else if (do_listen) {
166 if (argc > 1) bb_show_usage();
Denis Vlasenko5d687242007-01-12 20:59:31 +0000167 } else {
168 if (!argc || argc > 2) bb_show_usage();
169 }
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000170 } else {
171 if (argc != 3) bb_show_usage();
172 argc--;
173 argv++;
174 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000175
Mike Frysinger60a5c382005-05-06 04:45:38 +0000176 if (wsecs) {
177 signal(SIGALRM, timeout);
178 alarm(wsecs);
179 }
Denis Vlasenko9213a9e2006-09-17 16:28:10 +0000180
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000181 if (!cfd) {
Rob Landley1cca9482006-07-10 19:45:20 +0000182 if (do_listen) {
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000183 sfd = create_and_bind_stream_or_die(argv[0], lport);
Denis Vlasenko5d687242007-01-12 20:59:31 +0000184 xlisten(sfd, do_listen); /* can be > 1 */
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000185#if 0 /* nc-1.10 does not do this (without -v) */
Denis Vlasenko5d687242007-01-12 20:59:31 +0000186 /* If we didn't specify a port number,
187 * query and print it after listen() */
Rob Landley1cca9482006-07-10 19:45:20 +0000188 if (!lport) {
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000189 len_and_sockaddr lsa;
190 lsa.len = LSA_SIZEOF_SA;
191 getsockname(sfd, &lsa.u.sa, &lsa.len);
192 lport = get_nport(&lsa.u.sa);
Denis Vlasenko5d687242007-01-12 20:59:31 +0000193 fdprintf(2, "%d\n", ntohs(lport));
Rob Landley1cca9482006-07-10 19:45:20 +0000194 }
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000195#endif
Denis Vlasenko96e1b382007-09-30 23:50:48 +0000196 close_on_exec_on(sfd);
Denis Vlasenko5d687242007-01-12 20:59:31 +0000197 accept_again:
Denis Vlasenko703e2022007-01-22 14:12:08 +0000198 cfd = accept(sfd, NULL, 0);
Denis Vlasenko13858992006-10-08 12:49:22 +0000199 if (cfd < 0)
Rob Landley1cca9482006-07-10 19:45:20 +0000200 bb_perror_msg_and_die("accept");
Denis Vlasenko5d687242007-01-12 20:59:31 +0000201 if (!execparam)
202 close(sfd);
Rob Landley1cca9482006-07-10 19:45:20 +0000203 } else {
Denis Vlasenko5d687242007-01-12 20:59:31 +0000204 cfd = create_and_connect_stream_or_die(argv[0],
205 argv[1] ? bb_lookup_port(argv[1], "tcp", 0) : 0);
Rob Landley1cca9482006-07-10 19:45:20 +0000206 }
Matt Kraai1d702672001-02-07 04:09:23 +0000207 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000208
Mike Frysinger60a5c382005-05-06 04:45:38 +0000209 if (wsecs) {
210 alarm(0);
Denys Vlasenko28a105d2009-06-01 11:26:30 +0200211 /* Non-ignored signals revert to SIG_DFL on exec anyway */
Denis Vlasenko3fa36e22008-11-09 00:15:11 +0000212 /*signal(SIGALRM, SIG_DFL);*/
Mike Frysinger60a5c382005-05-06 04:45:38 +0000213 }
214
Eric Andersen1323c942002-04-26 23:59:12 +0000215 /* -e given? */
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000216 if (execparam) {
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200217 pid_t pid;
218 /* With more than one -l, repeatedly act as server */
Pascal Bellard926031b2010-07-04 15:32:38 +0200219 if (do_listen > 1 && (pid = xvfork()) != 0) {
220 /* parent */
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200221 /* prevent zombies */
222 signal(SIGCHLD, SIG_IGN);
223 close(cfd);
Denis Vlasenko5d687242007-01-12 20:59:31 +0000224 goto accept_again;
Rob Landley1cca9482006-07-10 19:45:20 +0000225 }
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200226 /* child, or main thread if only one -l */
Denis Vlasenkofa0b56d2008-07-01 16:09:07 +0000227 xmove_fd(cfd, 0);
228 xdup2(0, 1);
229 xdup2(0, 2);
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000230 IF_NC_EXTRA(BB_EXECVP(execparam[0], execparam);)
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200231 /* Don't print stuff or it will go over the wire... */
Rob Landley1cca9482006-07-10 19:45:20 +0000232 _exit(127);
233 }
234
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200235 /* Select loop copying stdin to cfd, and cfd to stdout */
Denis Vlasenko9213a9e2006-09-17 16:28:10 +0000236
Erik Andersene49d5ec2000-02-08 19:58:47 +0000237 FD_ZERO(&readfds);
Rob Landley1cca9482006-07-10 19:45:20 +0000238 FD_SET(cfd, &readfds);
Matt Kraaibfa79672000-12-15 22:34:34 +0000239 FD_SET(STDIN_FILENO, &readfds);
Eric Andersencc8ed391999-10-05 16:24:54 +0000240
Rob Landley1cca9482006-07-10 19:45:20 +0000241 for (;;) {
Erik Andersene49d5ec2000-02-08 19:58:47 +0000242 int fd;
Eric Andersen2ce1edc1999-10-12 15:42:48 +0000243 int ofd;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000244 int nread;
Eric Andersencc8ed391999-10-05 16:24:54 +0000245
Erik Andersene49d5ec2000-02-08 19:58:47 +0000246 testfds = readfds;
Eric Andersencc8ed391999-10-05 16:24:54 +0000247
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200248 if (select(cfd + 1, &testfds, NULL, NULL, NULL) < 0)
Manuel Novoa III cad53642003-03-19 09:13:01 +0000249 bb_perror_msg_and_die("select");
Eric Andersencc8ed391999-10-05 16:24:54 +0000250
Denis Vlasenko74324c82007-06-04 10:16:52 +0000251#define iobuf bb_common_bufsiz1
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200252 fd = STDIN_FILENO;
253 while (1) {
Erik Andersene49d5ec2000-02-08 19:58:47 +0000254 if (FD_ISSET(fd, &testfds)) {
Denis Vlasenko74324c82007-06-04 10:16:52 +0000255 nread = safe_read(fd, iobuf, sizeof(iobuf));
Rob Landley1cca9482006-07-10 19:45:20 +0000256 if (fd == cfd) {
Denis Vlasenko5d687242007-01-12 20:59:31 +0000257 if (nread < 1)
Bernhard Reutner-Fischer636a1f82008-05-19 09:29:47 +0000258 exit(EXIT_SUCCESS);
Matt Kraaibfa79672000-12-15 22:34:34 +0000259 ofd = STDOUT_FILENO;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000260 } else {
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200261 if (nread < 1) {
262 /* Close outgoing half-connection so they get EOF,
263 * but leave incoming alone so we can see response */
Rob Landley1cca9482006-07-10 19:45:20 +0000264 shutdown(cfd, 1);
Paul Fox7b71d742005-07-18 22:23:16 +0000265 FD_CLR(STDIN_FILENO, &readfds);
266 }
Rob Landley1cca9482006-07-10 19:45:20 +0000267 ofd = cfd;
Eric Andersen2ce1edc1999-10-12 15:42:48 +0000268 }
Denis Vlasenko74324c82007-06-04 10:16:52 +0000269 xwrite(ofd, iobuf, nread);
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200270 if (delay > 0)
271 sleep(delay);
Eric Andersen2ce1edc1999-10-12 15:42:48 +0000272 }
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200273 if (fd == cfd)
274 break;
275 fd = cfd;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000276 }
277 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000278}
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000279#endif