| /* 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 tarball for details. |
| */ |
| |
| #include "busybox.h" |
| |
| /* Lots of small differences in features |
| * when compared to "standard" nc |
| */ |
| |
| static void timeout(int signum) |
| { |
| bb_error_msg_and_die("timed out"); |
| } |
| |
| int nc_main(int argc, char **argv); |
| 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; |
| SKIP_NC_SERVER(const) unsigned do_listen = 0; |
| SKIP_NC_EXTRA (const) unsigned wsecs = 0; |
| SKIP_NC_EXTRA (const) unsigned delay = 0; |
| SKIP_NC_EXTRA (const int execparam = 0;) |
| USE_NC_EXTRA (char **execparam = NULL;) |
| len_and_sockaddr *lsa; |
| 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, |
| "" USE_NC_SERVER("lp:") USE_NC_EXTRA("w:i:f:e:") )) > 0 |
| ) { |
| if (ENABLE_NC_SERVER && opt=='l') USE_NC_SERVER(do_listen++); |
| else if (ENABLE_NC_SERVER && opt=='p') { |
| USE_NC_SERVER(lport = bb_lookup_port(optarg, "tcp", 0)); |
| } |
| else if (ENABLE_NC_EXTRA && opt=='w') USE_NC_EXTRA( wsecs = xatou(optarg)); |
| else if (ENABLE_NC_EXTRA && opt=='i') USE_NC_EXTRA( delay = xatou(optarg)); |
| else if (ENABLE_NC_EXTRA && opt=='f') USE_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"). */ |
| USE_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[arvc] (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(); |
| // Listen or file modes need zero arguments, client mode needs 2 |
| if (do_listen || cfd) { |
| if (argc) 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) { |
| /* create_and_bind_stream_or_die(NULL, lport) |
| * would've work wonderfully, but we need |
| * to know lsa */ |
| sfd = xsocket_stream(&lsa); |
| if (lport) |
| set_nport(lsa, htons(lport)); |
| setsockopt_reuseaddr(sfd); |
| xbind(sfd, &lsa->sa, lsa->len); |
| xlisten(sfd, do_listen); /* can be > 1 */ |
| /* If we didn't specify a port number, |
| * query and print it after listen() */ |
| if (!lport) { |
| socklen_t addrlen = lsa->len; |
| getsockname(sfd, &lsa->sa, &addrlen); |
| lport = get_nport(lsa); |
| fdprintf(2, "%d\n", ntohs(lport)); |
| } |
| fcntl(sfd, F_SETFD, FD_CLOEXEC); |
| 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); |
| signal(SIGALRM, SIG_DFL); |
| } |
| |
| /* -e given? */ |
| if (execparam) { |
| signal(SIGCHLD, SIG_IGN); |
| // With more than one -l, repeatedly act as server. |
| if (do_listen > 1 && vfork()) { |
| /* parent */ |
| // This is a bit weird as cleanup goes, since we wind up with no |
| // stdin/stdout/stderr. But it's small and shouldn't hurt anything. |
| // We check for cfd == 0 above. |
| logmode = LOGMODE_NONE; |
| close(0); |
| close(1); |
| close(2); |
| goto accept_again; |
| } |
| /* child (or main thread if no multiple -l) */ |
| if (cfd) { |
| dup2(cfd, 0); |
| close(cfd); |
| } |
| dup2(0, 1); |
| dup2(0, 2); |
| USE_NC_EXTRA(execvp(execparam[0], execparam);) |
| /* Don't print stuff or it will go over the wire.... */ |
| _exit(127); |
| } |
| |
| // Select loop copying stdin to cfd, and cfd to stdout. |
| |
| FD_ZERO(&readfds); |
| FD_SET(cfd, &readfds); |
| FD_SET(STDIN_FILENO, &readfds); |
| |
| for (;;) { |
| int fd; |
| int ofd; |
| int nread; |
| |
| testfds = readfds; |
| |
| if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0) |
| bb_perror_msg_and_die("select"); |
| |
| for (fd = 0; fd < FD_SETSIZE; fd++) { |
| if (FD_ISSET(fd, &testfds)) { |
| nread = safe_read(fd, bb_common_bufsiz1, |
| sizeof(bb_common_bufsiz1)); |
| |
| if (fd == cfd) { |
| if (nread < 1) |
| exit(0); |
| 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, 1); |
| FD_CLR(STDIN_FILENO, &readfds); |
| } |
| ofd = cfd; |
| } |
| |
| xwrite(ofd, bb_common_bufsiz1, nread); |
| if (delay > 0) sleep(delay); |
| } |
| } |
| } |
| } |