| /* vi: set sw=4 ts=4: */ |
| /* nc: mini-netcat - built from the ground up for LRP |
| * |
| * Copyright (C) 1998, 1999 Charles P. Wright |
| * Copyright (C) 1998 Dave Cinege |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| */ |
| //config:config NC |
| //config: bool "nc" |
| //config: default y |
| //config: help |
| //config: A simple Unix utility which reads and writes data across network |
| //config: connections. |
| //config: |
| //config:config NC_SERVER |
| //config: bool "Netcat server options (-l)" |
| //config: default y |
| //config: depends on NC |
| //config: help |
| //config: Allow netcat to act as a server. |
| //config: |
| //config:config NC_EXTRA |
| //config: bool "Netcat extensions (-eiw and -f FILE)" |
| //config: default y |
| //config: depends on NC |
| //config: help |
| //config: Add -e (support for executing the rest of the command line after |
| //config: making or receiving a successful connection), -i (delay interval for |
| //config: lines sent), -w (timeout for initial connection). |
| //config: |
| //config:config NC_110_COMPAT |
| //config: bool "Netcat 1.10 compatibility (+2.5k)" |
| //config: default n # off specially for Rob |
| //config: depends on NC |
| //config: help |
| //config: This option makes nc closely follow original nc-1.10. |
| //config: The code is about 2.5k bigger. It enables |
| //config: -s ADDR, -n, -u, -v, -o FILE, -z options, but loses |
| //config: busybox-specific extensions: -f FILE. |
| |
| //applet:IF_NC(APPLET(nc, BB_DIR_USR_BIN, BB_SUID_DROP)) |
| |
| //kbuild:lib-$(CONFIG_NC) += nc.o |
| |
| #include "libbb.h" |
| #include "common_bufsiz.h" |
| #if ENABLE_NC_110_COMPAT |
| # include "nc_bloaty.c" |
| #else |
| |
| //usage:#if !ENABLE_NC_110_COMPAT |
| //usage: |
| //usage:#if ENABLE_NC_SERVER || ENABLE_NC_EXTRA |
| //usage:#define NC_OPTIONS_STR "\n" |
| //usage:#else |
| //usage:#define NC_OPTIONS_STR |
| //usage:#endif |
| //usage: |
| //usage:#define nc_trivial_usage |
| //usage: IF_NC_EXTRA("[-iN] [-wN] ")IF_NC_SERVER("[-l] [-p PORT] ") |
| //usage: "["IF_NC_EXTRA("-f FILE|")"IPADDR PORT]"IF_NC_EXTRA(" [-e PROG]") |
| //usage:#define nc_full_usage "\n\n" |
| //usage: "Open a pipe to IP:PORT" IF_NC_EXTRA(" or FILE") |
| //usage: NC_OPTIONS_STR |
| //usage: IF_NC_SERVER( |
| //usage: "\n -l Listen mode, for inbound connects" |
| //usage: IF_NC_EXTRA( |
| //usage: "\n (use -ll with -e for persistent server)" |
| //usage: ) |
| //usage: "\n -p PORT Local port" |
| //usage: ) |
| //usage: IF_NC_EXTRA( |
| //usage: "\n -w SEC Connect timeout" |
| //usage: "\n -i SEC Delay interval for lines sent" |
| //usage: "\n -f FILE Use file (ala /dev/ttyS0) instead of network" |
| //usage: "\n -e PROG Run PROG after connect" |
| //usage: ) |
| //usage: |
| //usage:#define nc_notes_usage "" |
| //usage: IF_NC_EXTRA( |
| //usage: "To use netcat as a terminal emulator on a serial port:\n\n" |
| //usage: "$ stty 115200 -F /dev/ttyS0\n" |
| //usage: "$ stty raw -echo -ctlecho && nc -f /dev/ttyS0\n" |
| //usage: ) |
| //usage: |
| //usage:#define nc_example_usage |
| //usage: "$ nc foobar.somedomain.com 25\n" |
| //usage: "220 foobar ESMTP Exim 3.12 #1 Sat, 15 Apr 2000 00:03:02 -0600\n" |
| //usage: "help\n" |
| //usage: "214-Commands supported:\n" |
| //usage: "214- HELO EHLO MAIL RCPT DATA AUTH\n" |
| //usage: "214 NOOP QUIT RSET HELP\n" |
| //usage: "quit\n" |
| //usage: "221 foobar closing connection\n" |
| //usage: |
| //usage:#endif |
| |
| /* Lots of small differences in features |
| * when compared to "standard" nc |
| */ |
| |
| static void timeout(int signum UNUSED_PARAM) |
| { |
| bb_error_msg_and_die("timed out"); |
| } |
| |
| int nc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int nc_main(int argc, char **argv) |
| { |
| /* sfd sits _here_ only because of "repeat" option (-l -l). */ |
| int sfd = sfd; /* for gcc */ |
| int cfd = 0; |
| unsigned lport = 0; |
| IF_NOT_NC_SERVER(const) unsigned do_listen = 0; |
| IF_NOT_NC_EXTRA (const) unsigned wsecs = 0; |
| IF_NOT_NC_EXTRA (const) unsigned delay = 0; |
| IF_NOT_NC_EXTRA (const int execparam = 0;) |
| IF_NC_EXTRA (char **execparam = NULL;) |
| fd_set readfds, testfds; |
| int opt; /* must be signed (getopt returns -1) */ |
| |
| if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) { |
| /* getopt32 is _almost_ usable: |
| ** it cannot handle "... -e PROG -prog-opt" */ |
| while ((opt = getopt(argc, argv, |
| "" IF_NC_SERVER("lp:") IF_NC_EXTRA("w:i:f:e:") )) > 0 |
| ) { |
| if (ENABLE_NC_SERVER && opt == 'l') |
| IF_NC_SERVER(do_listen++); |
| else if (ENABLE_NC_SERVER && opt == 'p') |
| IF_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0)); |
| else if (ENABLE_NC_EXTRA && opt == 'w') |
| IF_NC_EXTRA( wsecs = xatou(optarg)); |
| else if (ENABLE_NC_EXTRA && opt == 'i') |
| IF_NC_EXTRA( delay = xatou(optarg)); |
| else if (ENABLE_NC_EXTRA && opt == 'f') |
| IF_NC_EXTRA( cfd = xopen(optarg, O_RDWR)); |
| else if (ENABLE_NC_EXTRA && opt == 'e' && optind <= argc) { |
| /* We cannot just 'break'. We should let getopt finish. |
| ** Or else we won't be able to find where |
| ** 'host' and 'port' params are |
| ** (think "nc -w 60 host port -e PROG"). */ |
| IF_NC_EXTRA( |
| char **p; |
| // +2: one for progname (optarg) and one for NULL |
| execparam = xzalloc(sizeof(char*) * (argc - optind + 2)); |
| p = execparam; |
| *p++ = optarg; |
| while (optind < argc) { |
| *p++ = argv[optind++]; |
| } |
| ) |
| /* optind points to argv[argc] (NULL) now. |
| ** FIXME: we assume that getopt will not count options |
| ** possibly present on "-e PROG ARGS" and will not |
| ** include them into final value of optind |
| ** which is to be used ... */ |
| } else bb_show_usage(); |
| } |
| argv += optind; /* ... here! */ |
| argc -= optind; |
| // -l and -f don't mix |
| if (do_listen && cfd) bb_show_usage(); |
| // File mode needs need zero arguments, listen mode needs zero or one, |
| // client mode needs one or two |
| if (cfd) { |
| if (argc) bb_show_usage(); |
| } else if (do_listen) { |
| if (argc > 1) bb_show_usage(); |
| } else { |
| if (!argc || argc > 2) bb_show_usage(); |
| } |
| } else { |
| if (argc != 3) bb_show_usage(); |
| argc--; |
| argv++; |
| } |
| |
| if (wsecs) { |
| signal(SIGALRM, timeout); |
| alarm(wsecs); |
| } |
| |
| if (!cfd) { |
| if (do_listen) { |
| sfd = create_and_bind_stream_or_die(argv[0], lport); |
| xlisten(sfd, do_listen); /* can be > 1 */ |
| #if 0 /* nc-1.10 does not do this (without -v) */ |
| /* If we didn't specify a port number, |
| * query and print it after listen() */ |
| if (!lport) { |
| len_and_sockaddr lsa; |
| lsa.len = LSA_SIZEOF_SA; |
| getsockname(sfd, &lsa.u.sa, &lsa.len); |
| lport = get_nport(&lsa.u.sa); |
| fdprintf(2, "%d\n", ntohs(lport)); |
| } |
| #endif |
| close_on_exec_on(sfd); |
| accept_again: |
| cfd = accept(sfd, NULL, 0); |
| if (cfd < 0) |
| bb_perror_msg_and_die("accept"); |
| if (!execparam) |
| close(sfd); |
| } else { |
| cfd = create_and_connect_stream_or_die(argv[0], |
| argv[1] ? bb_lookup_port(argv[1], "tcp", 0) : 0); |
| } |
| } |
| |
| if (wsecs) { |
| alarm(0); |
| /* Non-ignored signals revert to SIG_DFL on exec anyway */ |
| /*signal(SIGALRM, SIG_DFL);*/ |
| } |
| |
| /* -e given? */ |
| if (execparam) { |
| pid_t pid; |
| /* With more than one -l, repeatedly act as server */ |
| if (do_listen > 1 && (pid = xvfork()) != 0) { |
| /* parent */ |
| /* prevent zombies */ |
| signal(SIGCHLD, SIG_IGN); |
| close(cfd); |
| goto accept_again; |
| } |
| /* child, or main thread if only one -l */ |
| xmove_fd(cfd, 0); |
| xdup2(0, 1); |
| /*xdup2(0, 2); - original nc 1.10 does this, we don't */ |
| IF_NC_EXTRA(BB_EXECVP(execparam[0], execparam);) |
| IF_NC_EXTRA(bb_perror_msg_and_die("can't execute '%s'", execparam[0]);) |
| } |
| |
| /* Select loop copying stdin to cfd, and cfd to stdout */ |
| |
| FD_ZERO(&readfds); |
| FD_SET(cfd, &readfds); |
| FD_SET(STDIN_FILENO, &readfds); |
| |
| #define iobuf bb_common_bufsiz1 |
| setup_common_bufsiz(); |
| for (;;) { |
| int fd; |
| int ofd; |
| int nread; |
| |
| testfds = readfds; |
| |
| if (select(cfd + 1, &testfds, NULL, NULL, NULL) < 0) |
| bb_perror_msg_and_die("select"); |
| |
| fd = STDIN_FILENO; |
| while (1) { |
| if (FD_ISSET(fd, &testfds)) { |
| nread = safe_read(fd, iobuf, COMMON_BUFSIZE); |
| if (fd == cfd) { |
| if (nread < 1) |
| exit(EXIT_SUCCESS); |
| ofd = STDOUT_FILENO; |
| } else { |
| if (nread < 1) { |
| /* Close outgoing half-connection so they get EOF, |
| * but leave incoming alone so we can see response */ |
| shutdown(cfd, SHUT_WR); |
| FD_CLR(STDIN_FILENO, &readfds); |
| } |
| ofd = cfd; |
| } |
| xwrite(ofd, iobuf, nread); |
| if (delay > 0) |
| sleep(delay); |
| } |
| if (fd == cfd) |
| break; |
| fd = cfd; |
| } |
| } |
| } |
| #endif |