[821] | 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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[1765] | 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 tarball for details.
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| 8 | */
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[821] | 9 |
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[1765] | 10 | #include "libbb.h"
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[821] | 11 |
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[1765] | 12 | #if ENABLE_DESKTOP
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| 13 | #include "nc_bloaty.c"
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| 14 | #else
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[821] | 15 |
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[1765] | 16 | /* Lots of small differences in features
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| 17 | * when compared to "standard" nc
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| 18 | */
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[821] | 19 |
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| 20 | static void timeout(int signum)
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| 21 | {
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[1765] | 22 | bb_error_msg_and_die("timed out");
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[821] | 23 | }
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| 24 |
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[1765] | 25 | int nc_main(int argc, char **argv);
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[821] | 26 | int nc_main(int argc, char **argv)
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| 27 | {
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[1765] | 28 | /* sfd sits _here_ only because of "repeat" option (-l -l). */
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| 29 | int sfd = sfd; /* for gcc */
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| 30 | int cfd = 0;
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| 31 | unsigned lport = 0;
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| 32 | SKIP_NC_SERVER(const) unsigned do_listen = 0;
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| 33 | SKIP_NC_EXTRA (const) unsigned wsecs = 0;
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| 34 | SKIP_NC_EXTRA (const) unsigned delay = 0;
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| 35 | SKIP_NC_EXTRA (const int execparam = 0;)
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| 36 | USE_NC_EXTRA (char **execparam = NULL;)
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| 37 | len_and_sockaddr *lsa;
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[821] | 38 | fd_set readfds, testfds;
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[1765] | 39 | int opt; /* must be signed (getopt returns -1) */
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[821] | 40 |
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[1765] | 41 | if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) {
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| 42 | /* getopt32 is _almost_ usable:
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| 43 | ** it cannot handle "... -e prog -prog-opt" */
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| 44 | while ((opt = getopt(argc, argv,
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| 45 | "" USE_NC_SERVER("lp:") USE_NC_EXTRA("w:i:f:e:") )) > 0
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| 46 | ) {
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| 47 | if (ENABLE_NC_SERVER && opt=='l') USE_NC_SERVER(do_listen++);
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| 48 | else if (ENABLE_NC_SERVER && opt=='p') {
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| 49 | USE_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0));
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| 50 | }
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| 51 | else if (ENABLE_NC_EXTRA && opt=='w') USE_NC_EXTRA( wsecs = xatou(optarg));
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| 52 | else if (ENABLE_NC_EXTRA && opt=='i') USE_NC_EXTRA( delay = xatou(optarg));
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| 53 | else if (ENABLE_NC_EXTRA && opt=='f') USE_NC_EXTRA( cfd = xopen(optarg, O_RDWR));
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| 54 | else if (ENABLE_NC_EXTRA && opt=='e' && optind<=argc) {
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| 55 | /* We cannot just 'break'. We should let getopt finish.
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| 56 | ** Or else we won't be able to find where
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| 57 | ** 'host' and 'port' params are
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| 58 | ** (think "nc -w 60 host port -e prog"). */
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| 59 | USE_NC_EXTRA(
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| 60 | char **p;
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| 61 | // +2: one for progname (optarg) and one for NULL
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| 62 | execparam = xzalloc(sizeof(char*) * (argc - optind + 2));
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| 63 | p = execparam;
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| 64 | *p++ = optarg;
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| 65 | while (optind < argc) {
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| 66 | *p++ = argv[optind++];
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| 67 | }
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| 68 | )
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| 69 | /* optind points to argv[arvc] (NULL) now.
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| 70 | ** FIXME: we assume that getopt will not count options
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| 71 | ** possibly present on "-e prog args" and will not
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| 72 | ** include them into final value of optind
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| 73 | ** which is to be used ... */
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| 74 | } else bb_show_usage();
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[821] | 75 | }
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[1765] | 76 | argv += optind; /* ... here! */
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| 77 | argc -= optind;
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| 78 | // -l and -f don't mix
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| 79 | if (do_listen && cfd) bb_show_usage();
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| 80 | // Listen or file modes need zero arguments, client mode needs 2
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| 81 | if (do_listen || cfd) {
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| 82 | if (argc) bb_show_usage();
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| 83 | } else {
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| 84 | if (!argc || argc > 2) bb_show_usage();
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| 85 | }
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| 86 | } else {
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| 87 | if (argc != 3) bb_show_usage();
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| 88 | argc--;
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| 89 | argv++;
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[821] | 90 | }
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| 91 |
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| 92 | if (wsecs) {
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| 93 | signal(SIGALRM, timeout);
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| 94 | alarm(wsecs);
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| 95 | }
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| 96 |
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[1765] | 97 | if (!cfd) {
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| 98 | if (do_listen) {
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| 99 | /* create_and_bind_stream_or_die(NULL, lport)
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| 100 | * would've work wonderfully, but we need
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| 101 | * to know lsa */
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| 102 | sfd = xsocket_stream(&lsa);
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| 103 | if (lport)
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| 104 | set_nport(lsa, htons(lport));
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| 105 | setsockopt_reuseaddr(sfd);
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| 106 | xbind(sfd, &lsa->sa, lsa->len);
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| 107 | xlisten(sfd, do_listen); /* can be > 1 */
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| 108 | /* If we didn't specify a port number,
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| 109 | * query and print it after listen() */
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| 110 | if (!lport) {
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| 111 | socklen_t addrlen = lsa->len;
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| 112 | getsockname(sfd, &lsa->sa, &addrlen);
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| 113 | lport = get_nport(&lsa->sa);
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| 114 | fdprintf(2, "%d\n", ntohs(lport));
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| 115 | }
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| 116 | fcntl(sfd, F_SETFD, FD_CLOEXEC);
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| 117 | accept_again:
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| 118 | cfd = accept(sfd, NULL, 0);
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| 119 | if (cfd < 0)
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| 120 | bb_perror_msg_and_die("accept");
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| 121 | if (!execparam)
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| 122 | close(sfd);
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| 123 | } else {
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| 124 | cfd = create_and_connect_stream_or_die(argv[0],
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| 125 | argv[1] ? bb_lookup_port(argv[1], "tcp", 0) : 0);
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| 126 | }
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[821] | 127 | }
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| 128 |
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| 129 | if (wsecs) {
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| 130 | alarm(0);
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| 131 | signal(SIGALRM, SIG_DFL);
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| 132 | }
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| 133 |
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| 134 | /* -e given? */
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[1765] | 135 | if (execparam) {
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| 136 | signal(SIGCHLD, SIG_IGN);
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| 137 | // With more than one -l, repeatedly act as server.
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| 138 | if (do_listen > 1 && vfork()) {
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| 139 | /* parent */
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| 140 | // This is a bit weird as cleanup goes, since we wind up with no
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| 141 | // stdin/stdout/stderr. But it's small and shouldn't hurt anything.
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| 142 | // We check for cfd == 0 above.
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| 143 | logmode = LOGMODE_NONE;
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| 144 | close(0);
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| 145 | close(1);
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| 146 | close(2);
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| 147 | goto accept_again;
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| 148 | }
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| 149 | /* child (or main thread if no multiple -l) */
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| 150 | if (cfd) {
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| 151 | dup2(cfd, 0);
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| 152 | close(cfd);
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| 153 | }
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[821] | 154 | dup2(0, 1);
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| 155 | dup2(0, 2);
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[1765] | 156 | USE_NC_EXTRA(BB_EXECVP(execparam[0], execparam);)
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[821] | 157 | /* Don't print stuff or it will go over the wire.... */
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[1765] | 158 | _exit(127);
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[821] | 159 | }
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| 160 |
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[1765] | 161 | // Select loop copying stdin to cfd, and cfd to stdout.
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| 162 |
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[821] | 163 | FD_ZERO(&readfds);
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[1765] | 164 | FD_SET(cfd, &readfds);
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[821] | 165 | FD_SET(STDIN_FILENO, &readfds);
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| 166 |
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[1765] | 167 | for (;;) {
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[821] | 168 | int fd;
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| 169 | int ofd;
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| 170 | int nread;
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| 171 |
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| 172 | testfds = readfds;
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| 173 |
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| 174 | if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0)
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| 175 | bb_perror_msg_and_die("select");
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| 176 |
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[1765] | 177 | #define iobuf bb_common_bufsiz1
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[821] | 178 | for (fd = 0; fd < FD_SETSIZE; fd++) {
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| 179 | if (FD_ISSET(fd, &testfds)) {
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[1765] | 180 | nread = safe_read(fd, iobuf, sizeof(iobuf));
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| 181 | if (fd == cfd) {
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| 182 | if (nread < 1)
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[821] | 183 | exit(0);
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| 184 | ofd = STDOUT_FILENO;
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| 185 | } else {
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[1765] | 186 | if (nread<1) {
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| 187 | // Close outgoing half-connection so they get EOF, but
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| 188 | // leave incoming alone so we can see response.
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| 189 | shutdown(cfd, 1);
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[821] | 190 | FD_CLR(STDIN_FILENO, &readfds);
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| 191 | }
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[1765] | 192 | ofd = cfd;
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[821] | 193 | }
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[1765] | 194 | xwrite(ofd, iobuf, nread);
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| 195 | if (delay > 0) sleep(delay);
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[821] | 196 | }
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| 197 | }
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| 198 | }
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| 199 | }
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[1765] | 200 | #endif
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