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 tarball for details.
12 /* Lots of small differences in features
13 * when compared to "standard" nc
16 static void timeout(int signum)
18 bb_error_msg_and_die("timed out");
21 int nc_main(int argc, char **argv)
23 /* sfd sits _here_ only because of "repeat" option (-l -l). */
24 int sfd = sfd; /* for gcc */
27 SKIP_NC_SERVER(const) unsigned do_listen = 0;
28 SKIP_NC_EXTRA (const) unsigned wsecs = 0;
29 SKIP_NC_EXTRA (const) unsigned delay = 0;
30 SKIP_NC_EXTRA (const int execparam = 0;)
31 USE_NC_EXTRA (char **execparam = NULL;)
32 len_and_sockaddr *lsa;
33 fd_set readfds, testfds;
34 int opt; /* must be signed (getopt returns -1) */
36 if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) {
37 /* getopt32 is _almost_ usable:
38 ** it cannot handle "... -e prog -prog-opt" */
39 while ((opt = getopt(argc, argv,
40 "" USE_NC_SERVER("lp:") USE_NC_EXTRA("w:i:f:e:") )) > 0
42 if (ENABLE_NC_SERVER && opt=='l') USE_NC_SERVER(do_listen++);
43 else if (ENABLE_NC_SERVER && opt=='p') {
44 USE_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0));
46 else if (ENABLE_NC_EXTRA && opt=='w') USE_NC_EXTRA( wsecs = xatou(optarg));
47 else if (ENABLE_NC_EXTRA && opt=='i') USE_NC_EXTRA( delay = xatou(optarg));
48 else if (ENABLE_NC_EXTRA && opt=='f') USE_NC_EXTRA( cfd = xopen(optarg, O_RDWR));
49 else if (ENABLE_NC_EXTRA && opt=='e' && optind<=argc) {
50 /* We cannot just 'break'. We should let getopt finish.
51 ** Or else we won't be able to find where
52 ** 'host' and 'port' params are
53 ** (think "nc -w 60 host port -e prog"). */
56 // +2: one for progname (optarg) and one for NULL
57 execparam = xzalloc(sizeof(char*) * (argc - optind + 2));
60 while (optind < argc) {
61 *p++ = argv[optind++];
64 /* optind points to argv[arvc] (NULL) now.
65 ** FIXME: we assume that getopt will not count options
66 ** possibly present on "-e prog args" and will not
67 ** include them into final value of optind
68 ** which is to be used ... */
69 } else bb_show_usage();
71 argv += optind; /* ... here! */
73 // -l and -f don't mix
74 if (do_listen && cfd) bb_show_usage();
75 // Listen or file modes need zero arguments, client mode needs 2
76 if (do_listen || cfd) {
77 if (argc) bb_show_usage();
79 if (!argc || argc > 2) bb_show_usage();
82 if (argc != 3) bb_show_usage();
88 signal(SIGALRM, timeout);
94 /* create_and_bind_stream_or_die(NULL, lport)
95 * would've work wonderfully, but we need
97 sfd = xsocket_stream(&lsa);
99 set_nport(lsa, htons(lport));
100 setsockopt_reuseaddr(sfd);
101 xbind(sfd, &lsa->sa, lsa->len);
102 xlisten(sfd, do_listen); /* can be > 1 */
103 /* If we didn't specify a port number,
104 * query and print it after listen() */
106 socklen_t addrlen = lsa->len;
107 getsockname(sfd, &lsa->sa, &addrlen);
108 lport = get_nport(lsa);
109 fdprintf(2, "%d\n", ntohs(lport));
111 fcntl(sfd, F_SETFD, FD_CLOEXEC);
113 cfd = accept(sfd, NULL, 0);
115 bb_perror_msg_and_die("accept");
119 cfd = create_and_connect_stream_or_die(argv[0],
120 argv[1] ? bb_lookup_port(argv[1], "tcp", 0) : 0);
126 signal(SIGALRM, SIG_DFL);
131 signal(SIGCHLD, SIG_IGN);
132 // With more than one -l, repeatedly act as server.
133 if (do_listen > 1 && vfork()) {
135 // This is a bit weird as cleanup goes, since we wind up with no
136 // stdin/stdout/stderr. But it's small and shouldn't hurt anything.
137 // We check for cfd == 0 above.
138 logmode = LOGMODE_NONE;
144 /* child (or main thread if no multiple -l) */
151 USE_NC_EXTRA(execvp(execparam[0], execparam);)
152 /* Don't print stuff or it will go over the wire.... */
156 // Select loop copying stdin to cfd, and cfd to stdout.
159 FD_SET(cfd, &readfds);
160 FD_SET(STDIN_FILENO, &readfds);
169 if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0)
170 bb_perror_msg_and_die("select");
172 for (fd = 0; fd < FD_SETSIZE; fd++) {
173 if (FD_ISSET(fd, &testfds)) {
174 nread = safe_read(fd, bb_common_bufsiz1,
175 sizeof(bb_common_bufsiz1));
183 // Close outgoing half-connection so they get EOF, but
184 // leave incoming alone so we can see response.
186 FD_CLR(STDIN_FILENO, &readfds);
191 xwrite(ofd, bb_common_bufsiz1, nread);
192 if (delay > 0) sleep(delay);