1 /* vi: set sw=4 ts=4: */
2 /* nc: mini-netcat - built from the ground up for LRP
4 * Copyright (C) 1998, 1999 Charles P. Wright
5 * Copyright (C) 1998 Dave Cinege
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
13 //config: A simple Unix utility which reads and writes data across network
14 //config: connections.
16 //config:config NC_SERVER
17 //config: bool "Netcat server options (-l)"
19 //config: depends on NC
21 //config: Allow netcat to act as a server.
23 //config:config NC_EXTRA
24 //config: bool "Netcat extensions (-eiw and -f FILE)"
26 //config: depends on NC
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).
32 //config:config NC_110_COMPAT
33 //config: bool "Netcat 1.10 compatibility (+2.5k)"
34 //config: default n # off specially for Rob
35 //config: depends on NC
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
40 //config: busybox-specific extensions: -f FILE.
42 //applet:IF_NC(APPLET(nc, BB_DIR_USR_BIN, BB_SUID_DROP))
44 //kbuild:lib-$(CONFIG_NC) += nc.o
47 #include "common_bufsiz.h"
48 #if ENABLE_NC_110_COMPAT
49 # include "nc_bloaty.c"
52 //usage:#if !ENABLE_NC_110_COMPAT
54 //usage:#if ENABLE_NC_SERVER || ENABLE_NC_EXTRA
55 //usage:#define NC_OPTIONS_STR "\n"
57 //usage:#define NC_OPTIONS_STR
60 //usage:#define nc_trivial_usage
61 //usage: IF_NC_EXTRA("[-iN] [-wN] ")IF_NC_SERVER("[-l] [-p PORT] ")
62 //usage: "["IF_NC_EXTRA("-f FILE|")"IPADDR PORT]"IF_NC_EXTRA(" [-e PROG]")
63 //usage:#define nc_full_usage "\n\n"
64 //usage: "Open a pipe to IP:PORT" IF_NC_EXTRA(" or FILE")
65 //usage: NC_OPTIONS_STR
66 //usage: IF_NC_SERVER(
67 //usage: "\n -l Listen mode, for inbound connects"
69 //usage: "\n (use -ll with -e for persistent server)"
71 //usage: "\n -p PORT Local port"
74 //usage: "\n -w SEC Connect timeout"
75 //usage: "\n -i SEC Delay interval for lines sent"
76 //usage: "\n -f FILE Use file (ala /dev/ttyS0) instead of network"
77 //usage: "\n -e PROG Run PROG after connect"
80 //usage:#define nc_notes_usage ""
82 //usage: "To use netcat as a terminal emulator on a serial port:\n\n"
83 //usage: "$ stty 115200 -F /dev/ttyS0\n"
84 //usage: "$ stty raw -echo -ctlecho && nc -f /dev/ttyS0\n"
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"
91 //usage: "214-Commands supported:\n"
92 //usage: "214- HELO EHLO MAIL RCPT DATA AUTH\n"
93 //usage: "214 NOOP QUIT RSET HELP\n"
95 //usage: "221 foobar closing connection\n"
99 /* Lots of small differences in features
100 * when compared to "standard" nc
103 static void timeout(int signum UNUSED_PARAM)
105 bb_error_msg_and_die("timed out");
108 int nc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
109 int nc_main(int argc, char **argv)
111 /* sfd sits _here_ only because of "repeat" option (-l -l). */
112 int sfd = sfd; /* for gcc */
115 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;)
120 fd_set readfds, testfds;
121 int opt; /* must be signed (getopt returns -1) */
123 if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) {
124 /* getopt32 is _almost_ usable:
125 ** it cannot handle "... -e PROG -prog-opt" */
126 while ((opt = getopt(argc, argv,
127 "" IF_NC_SERVER("lp:") IF_NC_EXTRA("w:i:f:e:") )) > 0
129 if (ENABLE_NC_SERVER && opt == 'l')
130 IF_NC_SERVER(do_listen++);
131 else if (ENABLE_NC_SERVER && opt == 'p')
132 IF_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0));
133 else if (ENABLE_NC_EXTRA && opt == 'w')
134 IF_NC_EXTRA( wsecs = xatou(optarg));
135 else if (ENABLE_NC_EXTRA && opt == 'i')
136 IF_NC_EXTRA( delay = xatou(optarg));
137 else if (ENABLE_NC_EXTRA && opt == 'f')
138 IF_NC_EXTRA( cfd = xopen(optarg, O_RDWR));
139 else if (ENABLE_NC_EXTRA && opt == 'e' && optind <= argc) {
140 /* 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
143 ** (think "nc -w 60 host port -e PROG"). */
146 // +2: one for progname (optarg) and one for NULL
147 execparam = xzalloc(sizeof(char*) * (argc - optind + 2));
150 while (optind < argc) {
151 *p++ = argv[optind++];
154 /* optind points to argv[argc] (NULL) now.
155 ** FIXME: we assume that getopt will not count options
156 ** possibly present on "-e PROG ARGS" and will not
157 ** include them into final value of optind
158 ** which is to be used ... */
159 } else bb_show_usage();
161 argv += optind; /* ... here! */
163 // -l and -f don't mix
164 if (do_listen && cfd) bb_show_usage();
165 // File mode needs need zero arguments, listen mode needs zero or one,
166 // client mode needs one or two
168 if (argc) bb_show_usage();
169 } else if (do_listen) {
170 if (argc > 1) bb_show_usage();
172 if (!argc || argc > 2) bb_show_usage();
175 if (argc != 3) bb_show_usage();
181 signal(SIGALRM, timeout);
187 sfd = create_and_bind_stream_or_die(argv[0], lport);
188 xlisten(sfd, do_listen); /* can be > 1 */
189 #if 0 /* nc-1.10 does not do this (without -v) */
190 /* If we didn't specify a port number,
191 * query and print it after listen() */
193 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);
197 fdprintf(2, "%d\n", ntohs(lport));
200 close_on_exec_on(sfd);
202 cfd = accept(sfd, NULL, 0);
204 bb_perror_msg_and_die("accept");
208 cfd = create_and_connect_stream_or_die(argv[0],
209 argv[1] ? bb_lookup_port(argv[1], "tcp", 0) : 0);
215 /* Non-ignored signals revert to SIG_DFL on exec anyway */
216 /*signal(SIGALRM, SIG_DFL);*/
222 /* With more than one -l, repeatedly act as server */
223 if (do_listen > 1 && (pid = xvfork()) != 0) {
225 /* prevent zombies */
226 signal(SIGCHLD, SIG_IGN);
230 /* child, or main thread if only one -l */
233 /*xdup2(0, 2); - original nc 1.10 does this, we don't */
234 IF_NC_EXTRA(BB_EXECVP(execparam[0], execparam);)
235 IF_NC_EXTRA(bb_perror_msg_and_die("can't execute '%s'", execparam[0]);)
238 /* Select loop copying stdin to cfd, and cfd to stdout */
241 FD_SET(cfd, &readfds);
242 FD_SET(STDIN_FILENO, &readfds);
244 #define iobuf bb_common_bufsiz1
245 setup_common_bufsiz();
253 if (select(cfd + 1, &testfds, NULL, NULL, NULL) < 0)
254 bb_perror_msg_and_die("select");
258 if (FD_ISSET(fd, &testfds)) {
259 nread = safe_read(fd, iobuf, COMMON_BUFSIZE);
266 /* Close outgoing half-connection so they get EOF,
267 * but leave incoming alone so we can see response */
268 shutdown(cfd, SHUT_WR);
269 FD_CLR(STDIN_FILENO, &readfds);
273 xwrite(ofd, iobuf, nread);