| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /* nc: mini-netcat - built from the ground up for LRP
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| 3 | *
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| 4 | * Copyright (C) 1998, 1999 Charles P. Wright
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| 5 | * Copyright (C) 1998 Dave Cinege
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| 6 | *
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| 7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 8 | */
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| 9 |
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| 10 | #include "libbb.h"
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| 11 | #include "common_bufsiz.h"
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| 12 |
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| 13 | //config:config NC
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| 14 | //config: bool "nc"
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| 15 | //config: default y
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| 16 | //config: help
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| 17 | //config: A simple Unix utility which reads and writes data across network
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| 18 | //config: connections.
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| 19 | //config:
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| 20 | //config:config NC_SERVER
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| 21 | //config: bool "Netcat server options (-l)"
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| 22 | //config: default y
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| 23 | //config: depends on NC
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| 24 | //config: help
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| 25 | //config: Allow netcat to act as a server.
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| 26 | //config:
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| 27 | //config:config NC_EXTRA
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| 28 | //config: bool "Netcat extensions (-eiw and -f FILE)"
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| 29 | //config: default y
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| 30 | //config: depends on NC
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| 31 | //config: help
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| 32 | //config: Add -e (support for executing the rest of the command line after
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| 33 | //config: making or receiving a successful connection), -i (delay interval for
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| 34 | //config: lines sent), -w (timeout for initial connection).
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| 35 | //config:
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| 36 | //config:config NC_110_COMPAT
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| 37 | //config: bool "Netcat 1.10 compatibility (+2.5k)"
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| 38 | //config: default n # off specially for Rob
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| 39 | //config: depends on NC
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| 40 | //config: help
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| 41 | //config: This option makes nc closely follow original nc-1.10.
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| 42 | //config: The code is about 2.5k bigger. It enables
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| 43 | //config: -s ADDR, -n, -u, -v, -o FILE, -z options, but loses
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| 44 | //config: busybox-specific extensions: -f FILE.
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| 45 |
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| 46 | #if ENABLE_NC_110_COMPAT
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| 47 | # include "nc_bloaty.c"
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| 48 | #else
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| 49 |
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| 50 | //usage:#if !ENABLE_NC_110_COMPAT
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| 51 | //usage:
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| 52 | //usage:#if ENABLE_NC_SERVER || ENABLE_NC_EXTRA
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| 53 | //usage:#define NC_OPTIONS_STR "\n"
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| 54 | //usage:#else
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| 55 | //usage:#define NC_OPTIONS_STR
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| 56 | //usage:#endif
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| 57 | //usage:
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| 58 | //usage:#define nc_trivial_usage
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| 59 | //usage: IF_NC_EXTRA("[-iN] [-wN] ")IF_NC_SERVER("[-l] [-p PORT] ")
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| 60 | //usage: "["IF_NC_EXTRA("-f FILE|")"IPADDR PORT]"IF_NC_EXTRA(" [-e PROG]")
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| 61 | //usage:#define nc_full_usage "\n\n"
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| 62 | //usage: "Open a pipe to IP:PORT" IF_NC_EXTRA(" or FILE")
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| 63 | //usage: NC_OPTIONS_STR
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| 64 | //usage: IF_NC_SERVER(
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| 65 | //usage: "\n -l Listen mode, for inbound connects"
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| 66 | //usage: IF_NC_EXTRA(
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| 67 | //usage: "\n (use -ll with -e for persistent server)"
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| 68 | //usage: )
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| 69 | //usage: "\n -p PORT Local port"
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| 70 | //usage: )
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| 71 | //usage: IF_NC_EXTRA(
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| 72 | //usage: "\n -w SEC Connect timeout"
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| 73 | //usage: "\n -i SEC Delay interval for lines sent"
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| 74 | //usage: "\n -f FILE Use file (ala /dev/ttyS0) instead of network"
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| 75 | //usage: "\n -e PROG Run PROG after connect"
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| 76 | //usage: )
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| 77 | //usage:
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| 78 | //usage:#define nc_notes_usage ""
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| 79 | //usage: IF_NC_EXTRA(
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| 80 | //usage: "To use netcat as a terminal emulator on a serial port:\n\n"
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| 81 | //usage: "$ stty 115200 -F /dev/ttyS0\n"
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| 82 | //usage: "$ stty raw -echo -ctlecho && nc -f /dev/ttyS0\n"
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| 83 | //usage: )
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| 84 | //usage:
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| 85 | //usage:#define nc_example_usage
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| 86 | //usage: "$ nc foobar.somedomain.com 25\n"
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| 87 | //usage: "220 foobar ESMTP Exim 3.12 #1 Sat, 15 Apr 2000 00:03:02 -0600\n"
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| 88 | //usage: "help\n"
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| 89 | //usage: "214-Commands supported:\n"
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| 90 | //usage: "214- HELO EHLO MAIL RCPT DATA AUTH\n"
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| 91 | //usage: "214 NOOP QUIT RSET HELP\n"
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| 92 | //usage: "quit\n"
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| 93 | //usage: "221 foobar closing connection\n"
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| 94 | //usage:
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| 95 | //usage:#endif
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| 96 |
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| 97 | /* Lots of small differences in features
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| 98 | * when compared to "standard" nc
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| 99 | */
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| 100 |
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| 101 | static void timeout(int signum UNUSED_PARAM)
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| 102 | {
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| 103 | bb_error_msg_and_die("timed out");
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| 104 | }
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| 105 |
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| 106 | int nc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 107 | int nc_main(int argc, char **argv)
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| 108 | {
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| 109 | /* sfd sits _here_ only because of "repeat" option (-l -l). */
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| 110 | int sfd = sfd; /* for gcc */
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| 111 | int cfd = 0;
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| 112 | unsigned lport = 0;
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| 113 | IF_NOT_NC_SERVER(const) unsigned do_listen = 0;
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| 114 | IF_NOT_NC_EXTRA (const) unsigned wsecs = 0;
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| 115 | IF_NOT_NC_EXTRA (const) unsigned delay = 0;
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| 116 | IF_NOT_NC_EXTRA (const int execparam = 0;)
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| 117 | IF_NC_EXTRA (char **execparam = NULL;)
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| 118 | fd_set readfds, testfds;
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| 119 | int opt; /* must be signed (getopt returns -1) */
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| 120 |
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| 121 | if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) {
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| 122 | /* getopt32 is _almost_ usable:
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| 123 | ** it cannot handle "... -e PROG -prog-opt" */
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| 124 | while ((opt = getopt(argc, argv,
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| 125 | "" IF_NC_SERVER("lp:") IF_NC_EXTRA("w:i:f:e:") )) > 0
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| 126 | ) {
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| 127 | if (ENABLE_NC_SERVER && opt == 'l')
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| 128 | IF_NC_SERVER(do_listen++);
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| 129 | else if (ENABLE_NC_SERVER && opt == 'p')
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| 130 | IF_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0));
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| 131 | else if (ENABLE_NC_EXTRA && opt == 'w')
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| 132 | IF_NC_EXTRA( wsecs = xatou(optarg));
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| 133 | else if (ENABLE_NC_EXTRA && opt == 'i')
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| 134 | IF_NC_EXTRA( delay = xatou(optarg));
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| 135 | else if (ENABLE_NC_EXTRA && opt == 'f')
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| 136 | IF_NC_EXTRA( cfd = xopen(optarg, O_RDWR));
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| 137 | else if (ENABLE_NC_EXTRA && opt == 'e' && optind <= argc) {
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| 138 | /* We cannot just 'break'. We should let getopt finish.
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| 139 | ** Or else we won't be able to find where
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| 140 | ** 'host' and 'port' params are
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| 141 | ** (think "nc -w 60 host port -e PROG"). */
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| 142 | IF_NC_EXTRA(
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| 143 | char **p;
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| 144 | // +2: one for progname (optarg) and one for NULL
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| 145 | execparam = xzalloc(sizeof(char*) * (argc - optind + 2));
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| 146 | p = execparam;
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| 147 | *p++ = optarg;
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| 148 | while (optind < argc) {
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| 149 | *p++ = argv[optind++];
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| 150 | }
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| 151 | )
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| 152 | /* optind points to argv[argc] (NULL) now.
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| 153 | ** FIXME: we assume that getopt will not count options
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| 154 | ** possibly present on "-e PROG ARGS" and will not
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| 155 | ** include them into final value of optind
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| 156 | ** which is to be used ... */
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| 157 | } else bb_show_usage();
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| 158 | }
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| 159 | argv += optind; /* ... here! */
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| 160 | argc -= optind;
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| 161 | // -l and -f don't mix
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| 162 | if (do_listen && cfd) bb_show_usage();
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| 163 | // File mode needs need zero arguments, listen mode needs zero or one,
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| 164 | // client mode needs one or two
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| 165 | if (cfd) {
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| 166 | if (argc) bb_show_usage();
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| 167 | } else if (do_listen) {
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| 168 | if (argc > 1) bb_show_usage();
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| 169 | } else {
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| 170 | if (!argc || argc > 2) bb_show_usage();
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| 171 | }
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| 172 | } else {
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| 173 | if (argc != 3) bb_show_usage();
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| 174 | argc--;
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| 175 | argv++;
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| 176 | }
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| 177 |
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| 178 | if (wsecs) {
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| 179 | signal(SIGALRM, timeout);
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| 180 | alarm(wsecs);
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| 181 | }
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| 182 |
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| 183 | if (!cfd) {
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| 184 | if (do_listen) {
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| 185 | sfd = create_and_bind_stream_or_die(argv[0], lport);
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| 186 | xlisten(sfd, do_listen); /* can be > 1 */
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| 187 | #if 0 /* nc-1.10 does not do this (without -v) */
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| 188 | /* If we didn't specify a port number,
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| 189 | * query and print it after listen() */
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| 190 | if (!lport) {
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| 191 | len_and_sockaddr lsa;
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| 192 | lsa.len = LSA_SIZEOF_SA;
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| 193 | getsockname(sfd, &lsa.u.sa, &lsa.len);
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| 194 | lport = get_nport(&lsa.u.sa);
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| 195 | fdprintf(2, "%d\n", ntohs(lport));
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| 196 | }
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| 197 | #endif
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| 198 | close_on_exec_on(sfd);
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| 199 | accept_again:
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| 200 | cfd = accept(sfd, NULL, 0);
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| 201 | if (cfd < 0)
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| 202 | bb_perror_msg_and_die("accept");
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| 203 | if (!execparam)
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| 204 | close(sfd);
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| 205 | } else {
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| 206 | cfd = create_and_connect_stream_or_die(argv[0],
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| 207 | argv[1] ? bb_lookup_port(argv[1], "tcp", 0) : 0);
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| 208 | }
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| 209 | }
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| 210 |
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| 211 | if (wsecs) {
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| 212 | alarm(0);
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| 213 | /* Non-ignored signals revert to SIG_DFL on exec anyway */
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| 214 | /*signal(SIGALRM, SIG_DFL);*/
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| 215 | }
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| 216 |
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| 217 | /* -e given? */
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| 218 | if (execparam) {
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| 219 | pid_t pid;
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| 220 | /* With more than one -l, repeatedly act as server */
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| 221 | if (do_listen > 1 && (pid = xvfork()) != 0) {
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| 222 | /* parent */
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| 223 | /* prevent zombies */
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| 224 | signal(SIGCHLD, SIG_IGN);
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| 225 | close(cfd);
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| 226 | goto accept_again;
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| 227 | }
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| 228 | /* child, or main thread if only one -l */
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| 229 | xmove_fd(cfd, 0);
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| 230 | xdup2(0, 1);
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| 231 | /*xdup2(0, 2); - original nc 1.10 does this, we don't */
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| 232 | IF_NC_EXTRA(BB_EXECVP(execparam[0], execparam);)
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| 233 | IF_NC_EXTRA(bb_perror_msg_and_die("can't execute '%s'", execparam[0]);)
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| 234 | }
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| 235 |
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| 236 | /* Select loop copying stdin to cfd, and cfd to stdout */
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| 237 |
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| 238 | FD_ZERO(&readfds);
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| 239 | FD_SET(cfd, &readfds);
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| 240 | FD_SET(STDIN_FILENO, &readfds);
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| 241 |
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| 242 | #define iobuf bb_common_bufsiz1
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| 243 | setup_common_bufsiz();
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| 244 | for (;;) {
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| 245 | int fd;
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| 246 | int ofd;
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| 247 | int nread;
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| 248 |
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| 249 | testfds = readfds;
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| 250 |
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| 251 | if (select(cfd + 1, &testfds, NULL, NULL, NULL) < 0)
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| 252 | bb_perror_msg_and_die("select");
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| 253 |
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| 254 | fd = STDIN_FILENO;
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| 255 | while (1) {
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| 256 | if (FD_ISSET(fd, &testfds)) {
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| 257 | nread = safe_read(fd, iobuf, COMMON_BUFSIZE);
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| 258 | if (fd == cfd) {
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| 259 | if (nread < 1)
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| 260 | exit(EXIT_SUCCESS);
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| 261 | ofd = STDOUT_FILENO;
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| 262 | } else {
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| 263 | if (nread < 1) {
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| 264 | /* Close outgoing half-connection so they get EOF,
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| 265 | * but leave incoming alone so we can see response */
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| 266 | shutdown(cfd, SHUT_WR);
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| 267 | FD_CLR(STDIN_FILENO, &readfds);
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| 268 | }
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| 269 | ofd = cfd;
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| 270 | }
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| 271 | xwrite(ofd, iobuf, nread);
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| 272 | if (delay > 0)
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| 273 | sleep(delay);
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| 274 | }
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| 275 | if (fd == cfd)
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| 276 | break;
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| 277 | fd = cfd;
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| 278 | }
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| 279 | }
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| 280 | }
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| 281 | #endif
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