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);
22 int nc_main(int argc, char **argv)
24 /* sfd sits _here_ only because of "repeat" option (-l -l). */
25 int sfd = sfd; /* for gcc */
28 SKIP_NC_SERVER(const) unsigned do_listen = 0;
29 SKIP_NC_EXTRA (const) unsigned wsecs = 0;
30 SKIP_NC_EXTRA (const) unsigned delay = 0;
31 SKIP_NC_EXTRA (const int execparam = 0;)
32 USE_NC_EXTRA (char **execparam = NULL;)
33 len_and_sockaddr *lsa;
34 fd_set readfds, testfds;
35 int opt; /* must be signed (getopt returns -1) */
37 if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) {
38 /* getopt32 is _almost_ usable:
39 ** it cannot handle "... -e prog -prog-opt" */
40 while ((opt = getopt(argc, argv,
41 "" USE_NC_SERVER("lp:") USE_NC_EXTRA("w:i:f:e:") )) > 0
43 if (ENABLE_NC_SERVER && opt=='l') USE_NC_SERVER(do_listen++);
44 else if (ENABLE_NC_SERVER && opt=='p') {
45 USE_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0));
47 else if (ENABLE_NC_EXTRA && opt=='w') USE_NC_EXTRA( wsecs = xatou(optarg));
48 else if (ENABLE_NC_EXTRA && opt=='i') USE_NC_EXTRA( delay = xatou(optarg));
49 else if (ENABLE_NC_EXTRA && opt=='f') USE_NC_EXTRA( cfd = xopen(optarg, O_RDWR));
50 else if (ENABLE_NC_EXTRA && opt=='e' && optind<=argc) {
51 /* We cannot just 'break'. We should let getopt finish.
52 ** Or else we won't be able to find where
53 ** 'host' and 'port' params are
54 ** (think "nc -w 60 host port -e prog"). */
57 // +2: one for progname (optarg) and one for NULL
58 execparam = xzalloc(sizeof(char*) * (argc - optind + 2));
61 while (optind < argc) {
62 *p++ = argv[optind++];
65 /* optind points to argv[arvc] (NULL) now.
66 ** FIXME: we assume that getopt will not count options
67 ** possibly present on "-e prog args" and will not
68 ** include them into final value of optind
69 ** which is to be used ... */
70 } else bb_show_usage();
72 argv += optind; /* ... here! */
74 // -l and -f don't mix
75 if (do_listen && cfd) bb_show_usage();
76 // Listen or file modes need zero arguments, client mode needs 2
77 if (do_listen || cfd) {
78 if (argc) bb_show_usage();
80 if (!argc || argc > 2) bb_show_usage();
83 if (argc != 3) bb_show_usage();
89 signal(SIGALRM, timeout);
95 /* create_and_bind_stream_or_die(NULL, lport)
96 * would've work wonderfully, but we need
98 sfd = xsocket_stream(&lsa);
100 set_nport(lsa, htons(lport));
101 setsockopt_reuseaddr(sfd);
102 xbind(sfd, &lsa->sa, lsa->len);
103 xlisten(sfd, do_listen); /* can be > 1 */
104 /* If we didn't specify a port number,
105 * query and print it after listen() */
107 socklen_t addrlen = lsa->len;
108 getsockname(sfd, &lsa->sa, &addrlen);
109 lport = get_nport(lsa);
110 fdprintf(2, "%d\n", ntohs(lport));
112 fcntl(sfd, F_SETFD, FD_CLOEXEC);
114 cfd = accept(sfd, NULL, 0);
116 bb_perror_msg_and_die("accept");
120 cfd = create_and_connect_stream_or_die(argv[0],
121 argv[1] ? bb_lookup_port(argv[1], "tcp", 0) : 0);
127 signal(SIGALRM, SIG_DFL);
132 signal(SIGCHLD, SIG_IGN);
133 // With more than one -l, repeatedly act as server.
134 if (do_listen > 1 && vfork()) {
136 // This is a bit weird as cleanup goes, since we wind up with no
137 // stdin/stdout/stderr. But it's small and shouldn't hurt anything.
138 // We check for cfd == 0 above.
139 logmode = LOGMODE_NONE;
145 /* child (or main thread if no multiple -l) */
152 USE_NC_EXTRA(BB_EXECVP(execparam[0], execparam);)
153 /* Don't print stuff or it will go over the wire.... */
157 // Select loop copying stdin to cfd, and cfd to stdout.
160 FD_SET(cfd, &readfds);
161 FD_SET(STDIN_FILENO, &readfds);
170 if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0)
171 bb_perror_msg_and_die("select");
173 for (fd = 0; fd < FD_SETSIZE; fd++) {
174 if (FD_ISSET(fd, &testfds)) {
175 nread = safe_read(fd, bb_common_bufsiz1,
176 sizeof(bb_common_bufsiz1));
184 // Close outgoing half-connection so they get EOF, but
185 // leave incoming alone so we can see response.
187 FD_CLR(STDIN_FILENO, &readfds);
192 xwrite(ofd, bb_common_bufsiz1, nread);
193 if (delay > 0) sleep(delay);