source: branches/3.2/mindi-busybox/networking/nc.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
File size: 7.9 KB
Line 
1/* vi: set sw=4 ts=4: */
2/* nc: mini-netcat - built from the ground up for LRP
3 *
4 * Copyright (C) 1998, 1999  Charles P. Wright
5 * Copyright (C) 1998  Dave Cinege
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
8 */
9
10#include "libbb.h"
11
12//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 n  # off specially for Rob
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"
47#else
48
49//usage:#if !ENABLE_NC_110_COMPAT
50//usage:
51//usage:#if ENABLE_NC_SERVER || ENABLE_NC_EXTRA
52//usage:#define NC_OPTIONS_STR "\n"
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
95/* Lots of small differences in features
96 * when compared to "standard" nc
97 */
98
99static void timeout(int signum UNUSED_PARAM)
100{
101    bb_error_msg_and_die("timed out");
102}
103
104int nc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
105int nc_main(int argc, char **argv)
106{
107    /* sfd sits _here_ only because of "repeat" option (-l -l). */
108    int sfd = sfd; /* for gcc */
109    int cfd = 0;
110    unsigned lport = 0;
111    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;)
116    fd_set readfds, testfds;
117    int opt; /* must be signed (getopt returns -1) */
118
119    if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) {
120        /* getopt32 is _almost_ usable:
121        ** it cannot handle "... -e PROG -prog-opt" */
122        while ((opt = getopt(argc, argv,
123            "" IF_NC_SERVER("lp:") IF_NC_EXTRA("w:i:f:e:") )) > 0
124        ) {
125            if (ENABLE_NC_SERVER && opt == 'l')
126                IF_NC_SERVER(do_listen++);
127            else if (ENABLE_NC_SERVER && opt == 'p')
128                IF_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0));
129            else if (ENABLE_NC_EXTRA && opt == 'w')
130                IF_NC_EXTRA( wsecs = xatou(optarg));
131            else if (ENABLE_NC_EXTRA && opt == 'i')
132                IF_NC_EXTRA( delay = xatou(optarg));
133            else if (ENABLE_NC_EXTRA && opt == 'f')
134                IF_NC_EXTRA( cfd = xopen(optarg, O_RDWR));
135            else if (ENABLE_NC_EXTRA && opt == 'e' && optind <= argc) {
136                /* 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
139                ** (think "nc -w 60 host port -e PROG"). */
140                IF_NC_EXTRA(
141                    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
152                ** possibly present on "-e PROG ARGS" and will not
153                ** include them into final value of optind
154                ** which is to be used ...  */
155            } else bb_show_usage();
156        }
157        argv += optind; /* ... here! */
158        argc -= optind;
159        // -l and -f don't mix
160        if (do_listen && cfd) bb_show_usage();
161        // File mode needs need zero arguments, listen mode needs zero or one,
162        // client mode needs one or two
163        if (cfd) {
164            if (argc) bb_show_usage();
165        } else if (do_listen) {
166            if (argc > 1) bb_show_usage();
167        } else {
168            if (!argc || argc > 2) bb_show_usage();
169        }
170    } else {
171        if (argc != 3) bb_show_usage();
172        argc--;
173        argv++;
174    }
175
176    if (wsecs) {
177        signal(SIGALRM, timeout);
178        alarm(wsecs);
179    }
180
181    if (!cfd) {
182        if (do_listen) {
183            sfd = create_and_bind_stream_or_die(argv[0], lport);
184            xlisten(sfd, do_listen); /* can be > 1 */
185#if 0  /* nc-1.10 does not do this (without -v) */
186            /* If we didn't specify a port number,
187             * query and print it after listen() */
188            if (!lport) {
189                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);
193                fdprintf(2, "%d\n", ntohs(lport));
194            }
195#endif
196            close_on_exec_on(sfd);
197 accept_again:
198            cfd = accept(sfd, NULL, 0);
199            if (cfd < 0)
200                bb_perror_msg_and_die("accept");
201            if (!execparam)
202                close(sfd);
203        } else {
204            cfd = create_and_connect_stream_or_die(argv[0],
205                argv[1] ? bb_lookup_port(argv[1], "tcp", 0) : 0);
206        }
207    }
208
209    if (wsecs) {
210        alarm(0);
211        /* Non-ignored signals revert to SIG_DFL on exec anyway */
212        /*signal(SIGALRM, SIG_DFL);*/
213    }
214
215    /* -e given? */
216    if (execparam) {
217        pid_t pid;
218        /* With more than one -l, repeatedly act as server */
219        if (do_listen > 1 && (pid = xvfork()) != 0) {
220            /* parent */
221            /* prevent zombies */
222            signal(SIGCHLD, SIG_IGN);
223            close(cfd);
224            goto accept_again;
225        }
226        /* child, or main thread if only one -l */
227        xmove_fd(cfd, 0);
228        xdup2(0, 1);
229        xdup2(0, 2);
230        IF_NC_EXTRA(BB_EXECVP(execparam[0], execparam);)
231        /* Don't print stuff or it will go over the wire... */
232        _exit(127);
233    }
234
235    /* Select loop copying stdin to cfd, and cfd to stdout */
236
237    FD_ZERO(&readfds);
238    FD_SET(cfd, &readfds);
239    FD_SET(STDIN_FILENO, &readfds);
240
241    for (;;) {
242        int fd;
243        int ofd;
244        int nread;
245
246        testfds = readfds;
247
248        if (select(cfd + 1, &testfds, NULL, NULL, NULL) < 0)
249            bb_perror_msg_and_die("select");
250
251#define iobuf bb_common_bufsiz1
252        fd = STDIN_FILENO;
253        while (1) {
254            if (FD_ISSET(fd, &testfds)) {
255                nread = safe_read(fd, iobuf, sizeof(iobuf));
256                if (fd == cfd) {
257                    if (nread < 1)
258                        exit(EXIT_SUCCESS);
259                    ofd = STDOUT_FILENO;
260                } else {
261                    if (nread < 1) {
262                        /* Close outgoing half-connection so they get EOF,
263                         * but leave incoming alone so we can see response */
264                        shutdown(cfd, 1);
265                        FD_CLR(STDIN_FILENO, &readfds);
266                    }
267                    ofd = cfd;
268                }
269                xwrite(ofd, iobuf, nread);
270                if (delay > 0)
271                    sleep(delay);
272            }
273            if (fd == cfd)
274                break;
275            fd = cfd;
276        }
277    }
278}
279#endif
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