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Erik Andersene49d5ec2000-02-08 19:58:47 +00001/* vi: set sw=4 ts=4: */
Denys Vlasenko0ef64bd2010-08-16 20:14:46 +02002/* nc: mini-netcat - built from the ground up for LRP
Denis Vlasenko9213a9e2006-09-17 16:28:10 +00003 *
Denys Vlasenko0ef64bd2010-08-16 20:14:46 +02004 * Copyright (C) 1998, 1999 Charles P. Wright
5 * Copyright (C) 1998 Dave Cinege
Denis Vlasenko9213a9e2006-09-17 16:28:10 +00006 *
Denys Vlasenko0ef64bd2010-08-16 20:14:46 +02007 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
Rob Landley1cca9482006-07-10 19:45:20 +00008 */
Denys Vlasenko77cc2c52010-06-27 04:22:02 +02009//config:config NC
Denys Vlasenko4eed2c62017-07-18 22:01:24 +020010//config: bool "nc (11 kb)"
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020011//config: default y
12//config: help
13//config: A simple Unix utility which reads and writes data across network
14//config: connections.
15//config:
16//config:config NC_SERVER
17//config: bool "Netcat server options (-l)"
18//config: default y
19//config: depends on NC
20//config: help
21//config: Allow netcat to act as a server.
22//config:
23//config:config NC_EXTRA
Denys Vlasenkoa14f3192013-02-28 11:09:14 +010024//config: bool "Netcat extensions (-eiw and -f FILE)"
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020025//config: default y
26//config: depends on NC
27//config: help
28//config: Add -e (support for executing the rest of the command line after
29//config: making or receiving a successful connection), -i (delay interval for
30//config: lines sent), -w (timeout for initial connection).
31//config:
32//config:config NC_110_COMPAT
33//config: bool "Netcat 1.10 compatibility (+2.5k)"
Denys Vlasenkofb4cb1c2010-07-18 23:02:36 +020034//config: default n # off specially for Rob
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020035//config: depends on NC
36//config: help
37//config: This option makes nc closely follow original nc-1.10.
38//config: The code is about 2.5k bigger. It enables
39//config: -s ADDR, -n, -u, -v, -o FILE, -z options, but loses
Denys Vlasenkoed954b62013-02-28 12:39:27 +010040//config: busybox-specific extensions: -f FILE.
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020041
Denys Vlasenko47367e12016-11-23 09:05:14 +010042//applet:IF_NC(APPLET(nc, BB_DIR_USR_BIN, BB_SUID_DROP))
43
44//kbuild:lib-$(CONFIG_NC) += nc.o
45
46#include "libbb.h"
47#include "common_bufsiz.h"
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020048#if ENABLE_NC_110_COMPAT
49# include "nc_bloaty.c"
Denis Vlasenko29fe7262007-04-05 20:26:28 +000050#else
51
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020052//usage:#if !ENABLE_NC_110_COMPAT
53//usage:
54//usage:#if ENABLE_NC_SERVER || ENABLE_NC_EXTRA
Denys Vlasenko66426762011-06-05 03:58:28 +020055//usage:#define NC_OPTIONS_STR "\n"
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020056//usage:#else
57//usage:#define NC_OPTIONS_STR
58//usage:#endif
59//usage:
60//usage:#define nc_trivial_usage
61//usage: IF_NC_EXTRA("[-iN] [-wN] ")IF_NC_SERVER("[-l] [-p PORT] ")
62//usage: "["IF_NC_EXTRA("-f FILE|")"IPADDR PORT]"IF_NC_EXTRA(" [-e PROG]")
63//usage:#define nc_full_usage "\n\n"
64//usage: "Open a pipe to IP:PORT" IF_NC_EXTRA(" or FILE")
65//usage: NC_OPTIONS_STR
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020066//usage: IF_NC_SERVER(
67//usage: "\n -l Listen mode, for inbound connects"
68//usage: IF_NC_EXTRA(
Denys Vlasenkoa14f3192013-02-28 11:09:14 +010069//usage: "\n (use -ll with -e for persistent server)"
70//usage: )
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020071//usage: "\n -p PORT Local port"
72//usage: )
Denys Vlasenkoa14f3192013-02-28 11:09:14 +010073//usage: IF_NC_EXTRA(
74//usage: "\n -w SEC Connect timeout"
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020075//usage: "\n -i SEC Delay interval for lines sent"
76//usage: "\n -f FILE Use file (ala /dev/ttyS0) instead of network"
Denys Vlasenkoa14f3192013-02-28 11:09:14 +010077//usage: "\n -e PROG Run PROG after connect"
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020078//usage: )
79//usage:
80//usage:#define nc_notes_usage ""
81//usage: IF_NC_EXTRA(
82//usage: "To use netcat as a terminal emulator on a serial port:\n\n"
83//usage: "$ stty 115200 -F /dev/ttyS0\n"
84//usage: "$ stty raw -echo -ctlecho && nc -f /dev/ttyS0\n"
85//usage: )
86//usage:
87//usage:#define nc_example_usage
88//usage: "$ nc foobar.somedomain.com 25\n"
89//usage: "220 foobar ESMTP Exim 3.12 #1 Sat, 15 Apr 2000 00:03:02 -0600\n"
90//usage: "help\n"
91//usage: "214-Commands supported:\n"
92//usage: "214- HELO EHLO MAIL RCPT DATA AUTH\n"
93//usage: "214 NOOP QUIT RSET HELP\n"
94//usage: "quit\n"
95//usage: "221 foobar closing connection\n"
96//usage:
97//usage:#endif
98
Denis Vlasenko5d687242007-01-12 20:59:31 +000099/* Lots of small differences in features
100 * when compared to "standard" nc
101 */
102
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +0000103static void timeout(int signum UNUSED_PARAM)
Mike Frysinger60a5c382005-05-06 04:45:38 +0000104{
Denis Vlasenko13858992006-10-08 12:49:22 +0000105 bb_error_msg_and_die("timed out");
Mike Frysinger60a5c382005-05-06 04:45:38 +0000106}
107
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +0000108int nc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Erik Andersen7ab9c7e2000-05-12 19:41:47 +0000109int nc_main(int argc, char **argv)
Eric Andersencc8ed391999-10-05 16:24:54 +0000110{
Denis Vlasenko5d687242007-01-12 20:59:31 +0000111 /* sfd sits _here_ only because of "repeat" option (-l -l). */
112 int sfd = sfd; /* for gcc */
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000113 int cfd = 0;
Denis Vlasenko31635552007-01-20 16:54:19 +0000114 unsigned lport = 0;
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000115 IF_NOT_NC_SERVER(const) unsigned do_listen = 0;
116 IF_NOT_NC_EXTRA (const) unsigned wsecs = 0;
117 IF_NOT_NC_EXTRA (const) unsigned delay = 0;
118 IF_NOT_NC_EXTRA (const int execparam = 0;)
119 IF_NC_EXTRA (char **execparam = NULL;)
Denys Vlasenko5b3b4682017-02-16 17:17:17 +0100120 struct pollfd pfds[2];
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000121 int opt; /* must be signed (getopt returns -1) */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000122
Denis Vlasenko9213a9e2006-09-17 16:28:10 +0000123 if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) {
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000124 /* getopt32 is _almost_ usable:
Denys Vlasenko77cc2c52010-06-27 04:22:02 +0200125 ** it cannot handle "... -e PROG -prog-opt" */
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000126 while ((opt = getopt(argc, argv,
Denys Vlasenko69675782013-01-14 01:34:48 +0100127 "" IF_NC_SERVER("lp:") IF_NC_EXTRA("w:i:f:e:") )) > 0
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000128 ) {
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000129 if (ENABLE_NC_SERVER && opt == 'l')
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000130 IF_NC_SERVER(do_listen++);
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000131 else if (ENABLE_NC_SERVER && opt == 'p')
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000132 IF_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0));
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000133 else if (ENABLE_NC_EXTRA && opt == 'w')
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000134 IF_NC_EXTRA( wsecs = xatou(optarg));
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000135 else if (ENABLE_NC_EXTRA && opt == 'i')
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000136 IF_NC_EXTRA( delay = xatou(optarg));
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000137 else if (ENABLE_NC_EXTRA && opt == 'f')
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000138 IF_NC_EXTRA( cfd = xopen(optarg, O_RDWR));
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000139 else if (ENABLE_NC_EXTRA && opt == 'e' && optind <= argc) {
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000140 /* We cannot just 'break'. We should let getopt finish.
141 ** Or else we won't be able to find where
142 ** 'host' and 'port' params are
Denys Vlasenko77cc2c52010-06-27 04:22:02 +0200143 ** (think "nc -w 60 host port -e PROG"). */
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000144 IF_NC_EXTRA(
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000145 char **p;
146 // +2: one for progname (optarg) and one for NULL
147 execparam = xzalloc(sizeof(char*) * (argc - optind + 2));
148 p = execparam;
149 *p++ = optarg;
150 while (optind < argc) {
151 *p++ = argv[optind++];
152 }
153 )
Denys Vlasenkoa14f3192013-02-28 11:09:14 +0100154 /* optind points to argv[argc] (NULL) now.
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000155 ** FIXME: we assume that getopt will not count options
Denys Vlasenko77cc2c52010-06-27 04:22:02 +0200156 ** possibly present on "-e PROG ARGS" and will not
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000157 ** include them into final value of optind
158 ** which is to be used ... */
Rob Landley1cca9482006-07-10 19:45:20 +0000159 } else bb_show_usage();
Matt Kraai1d702672001-02-07 04:09:23 +0000160 }
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000161 argv += optind; /* ... here! */
162 argc -= optind;
163 // -l and -f don't mix
164 if (do_listen && cfd) bb_show_usage();
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000165 // File mode needs need zero arguments, listen mode needs zero or one,
166 // client mode needs one or two
167 if (cfd) {
Denis Vlasenko5d687242007-01-12 20:59:31 +0000168 if (argc) bb_show_usage();
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000169 } else if (do_listen) {
170 if (argc > 1) bb_show_usage();
Denis Vlasenko5d687242007-01-12 20:59:31 +0000171 } else {
172 if (!argc || argc > 2) bb_show_usage();
173 }
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000174 } else {
175 if (argc != 3) bb_show_usage();
176 argc--;
177 argv++;
178 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000179
Mike Frysinger60a5c382005-05-06 04:45:38 +0000180 if (wsecs) {
181 signal(SIGALRM, timeout);
182 alarm(wsecs);
183 }
Denis Vlasenko9213a9e2006-09-17 16:28:10 +0000184
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000185 if (!cfd) {
Rob Landley1cca9482006-07-10 19:45:20 +0000186 if (do_listen) {
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000187 sfd = create_and_bind_stream_or_die(argv[0], lport);
Denis Vlasenko5d687242007-01-12 20:59:31 +0000188 xlisten(sfd, do_listen); /* can be > 1 */
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000189#if 0 /* nc-1.10 does not do this (without -v) */
Denis Vlasenko5d687242007-01-12 20:59:31 +0000190 /* If we didn't specify a port number,
191 * query and print it after listen() */
Rob Landley1cca9482006-07-10 19:45:20 +0000192 if (!lport) {
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000193 len_and_sockaddr lsa;
194 lsa.len = LSA_SIZEOF_SA;
195 getsockname(sfd, &lsa.u.sa, &lsa.len);
196 lport = get_nport(&lsa.u.sa);
Denis Vlasenko5d687242007-01-12 20:59:31 +0000197 fdprintf(2, "%d\n", ntohs(lport));
Rob Landley1cca9482006-07-10 19:45:20 +0000198 }
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000199#endif
Denis Vlasenko96e1b382007-09-30 23:50:48 +0000200 close_on_exec_on(sfd);
Denis Vlasenko5d687242007-01-12 20:59:31 +0000201 accept_again:
Denis Vlasenko703e2022007-01-22 14:12:08 +0000202 cfd = accept(sfd, NULL, 0);
Denis Vlasenko13858992006-10-08 12:49:22 +0000203 if (cfd < 0)
Rob Landley1cca9482006-07-10 19:45:20 +0000204 bb_perror_msg_and_die("accept");
Denis Vlasenko5d687242007-01-12 20:59:31 +0000205 if (!execparam)
206 close(sfd);
Rob Landley1cca9482006-07-10 19:45:20 +0000207 } else {
Denis Vlasenko5d687242007-01-12 20:59:31 +0000208 cfd = create_and_connect_stream_or_die(argv[0],
209 argv[1] ? bb_lookup_port(argv[1], "tcp", 0) : 0);
Rob Landley1cca9482006-07-10 19:45:20 +0000210 }
Matt Kraai1d702672001-02-07 04:09:23 +0000211 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000212
Mike Frysinger60a5c382005-05-06 04:45:38 +0000213 if (wsecs) {
214 alarm(0);
Denys Vlasenko28a105d2009-06-01 11:26:30 +0200215 /* Non-ignored signals revert to SIG_DFL on exec anyway */
Denis Vlasenko3fa36e22008-11-09 00:15:11 +0000216 /*signal(SIGALRM, SIG_DFL);*/
Mike Frysinger60a5c382005-05-06 04:45:38 +0000217 }
218
Eric Andersen1323c942002-04-26 23:59:12 +0000219 /* -e given? */
Denis Vlasenkod0e70af2006-10-16 01:10:28 +0000220 if (execparam) {
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200221 pid_t pid;
222 /* With more than one -l, repeatedly act as server */
Pascal Bellard926031b2010-07-04 15:32:38 +0200223 if (do_listen > 1 && (pid = xvfork()) != 0) {
224 /* parent */
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200225 /* prevent zombies */
226 signal(SIGCHLD, SIG_IGN);
227 close(cfd);
Denis Vlasenko5d687242007-01-12 20:59:31 +0000228 goto accept_again;
Rob Landley1cca9482006-07-10 19:45:20 +0000229 }
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200230 /* child, or main thread if only one -l */
Denis Vlasenkofa0b56d2008-07-01 16:09:07 +0000231 xmove_fd(cfd, 0);
232 xdup2(0, 1);
Denys Vlasenkoa14f3192013-02-28 11:09:14 +0100233 /*xdup2(0, 2); - original nc 1.10 does this, we don't */
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000234 IF_NC_EXTRA(BB_EXECVP(execparam[0], execparam);)
Denys Vlasenkoc56d1252013-03-17 22:59:51 +0100235 IF_NC_EXTRA(bb_perror_msg_and_die("can't execute '%s'", execparam[0]);)
Rob Landley1cca9482006-07-10 19:45:20 +0000236 }
237
Denys Vlasenko5b3b4682017-02-16 17:17:17 +0100238 /* loop copying stdin to cfd, and cfd to stdout */
Denis Vlasenko9213a9e2006-09-17 16:28:10 +0000239
Denys Vlasenko5b3b4682017-02-16 17:17:17 +0100240 pfds[0].fd = STDIN_FILENO;
241 pfds[0].events = POLLIN;
242 pfds[1].fd = cfd;
243 pfds[1].events = POLLIN;
Eric Andersencc8ed391999-10-05 16:24:54 +0000244
Denys Vlasenko9de2e5a2016-04-21 18:38:51 +0200245#define iobuf bb_common_bufsiz1
246 setup_common_bufsiz();
Rob Landley1cca9482006-07-10 19:45:20 +0000247 for (;;) {
Denys Vlasenko5b3b4682017-02-16 17:17:17 +0100248 int fdidx;
Eric Andersen2ce1edc1999-10-12 15:42:48 +0000249 int ofd;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000250 int nread;
Eric Andersencc8ed391999-10-05 16:24:54 +0000251
Denys Vlasenko5b3b4682017-02-16 17:17:17 +0100252 if (safe_poll(pfds, 2, -1) < 0)
253 bb_perror_msg_and_die("poll");
Eric Andersencc8ed391999-10-05 16:24:54 +0000254
Denys Vlasenko5b3b4682017-02-16 17:17:17 +0100255 fdidx = 0;
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200256 while (1) {
Denys Vlasenko5b3b4682017-02-16 17:17:17 +0100257 if (pfds[fdidx].revents) {
258 nread = safe_read(pfds[fdidx].fd, iobuf, COMMON_BUFSIZE);
259 if (fdidx != 0) {
Denis Vlasenko5d687242007-01-12 20:59:31 +0000260 if (nread < 1)
Bernhard Reutner-Fischer636a1f82008-05-19 09:29:47 +0000261 exit(EXIT_SUCCESS);
Matt Kraaibfa79672000-12-15 22:34:34 +0000262 ofd = STDOUT_FILENO;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000263 } else {
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200264 if (nread < 1) {
265 /* Close outgoing half-connection so they get EOF,
266 * but leave incoming alone so we can see response */
Denys Vlasenkoca54b662013-07-28 21:08:37 +0200267 shutdown(cfd, SHUT_WR);
Denys Vlasenko5b3b4682017-02-16 17:17:17 +0100268 pfds[0].fd = -1;
Paul Fox7b71d742005-07-18 22:23:16 +0000269 }
Rob Landley1cca9482006-07-10 19:45:20 +0000270 ofd = cfd;
Eric Andersen2ce1edc1999-10-12 15:42:48 +0000271 }
Denis Vlasenko74324c82007-06-04 10:16:52 +0000272 xwrite(ofd, iobuf, nread);
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200273 if (delay > 0)
274 sleep(delay);
Eric Andersen2ce1edc1999-10-12 15:42:48 +0000275 }
Denys Vlasenko5b3b4682017-02-16 17:17:17 +0100276 if (fdidx == 1)
Tomoya Adachi63416cc2009-08-03 02:59:22 +0200277 break;
Denys Vlasenko5b3b4682017-02-16 17:17:17 +0100278 fdidx++;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000279 }
280 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000281}
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000282#endif