| /* 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" |
| |
| #define xread bb_xread |
| |
| static void timeout(int signum) |
| { |
| bb_error_msg_and_die("Timed out"); |
| } |
| |
| int nc_main(int argc, char **argv) |
| { |
| int do_listen = 0, lport = 0, delay = 0, wsecs = 0, execflag = 0, opt, |
| sfd = 0, cfd; |
| struct sockaddr_in address; |
| struct hostent *hostinfo; |
| fd_set readfds, testfds; |
| char *infile = NULL; |
| |
| memset(&address, 0, sizeof(address)); |
| |
| if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) { |
| while ((opt = getopt(argc, argv, "lp:" USE_NC_EXTRA("i:ew:f:"))) > 0) { |
| if (ENABLE_NC_SERVER && opt=='l') do_listen++; |
| else if (ENABLE_NC_SERVER && opt=='p') |
| lport = bb_lookup_port(optarg, "tcp", 0); |
| else if (ENABLE_NC_EXTRA && opt=='w') wsecs = atoi(optarg); |
| else if (ENABLE_NC_EXTRA && opt=='i') delay = atoi(optarg); |
| else if (ENABLE_NC_EXTRA && opt=='f') infile = optarg; |
| else if (ENABLE_NC_EXTRA && opt=='e' && optind!=argc) { |
| execflag++; |
| break; |
| } else bb_show_usage(); |
| } |
| } |
| |
| |
| // For listen or file we need zero arguments, dialout is 2. |
| // For exec we need at least one more argument at the end, more ok |
| |
| opt = (do_listen || infile) ? 0 : 2 + execflag; |
| if (execflag ? argc-optind < opt : argc-optind!=opt || |
| (infile && do_listen)) |
| bb_show_usage(); |
| |
| if (wsecs) { |
| signal(SIGALRM, timeout); |
| alarm(wsecs); |
| } |
| |
| if (infile) cfd = bb_xopen(infile, O_RDWR); |
| else { |
| opt = 1; |
| sfd = bb_xsocket(AF_INET, SOCK_STREAM, 0); |
| fcntl(sfd, F_SETFD, FD_CLOEXEC); |
| setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof (opt)); |
| address.sin_family = AF_INET; |
| |
| // Set local port. |
| |
| if (lport != 0) { |
| address.sin_port = lport; |
| |
| bb_xbind(sfd, (struct sockaddr *) &address, sizeof(address)); |
| } |
| |
| if (do_listen) { |
| socklen_t addrlen = sizeof(address); |
| |
| bb_xlisten(sfd, do_listen); |
| |
| // If we didn't specify a port number, query and print it to stderr. |
| |
| if (!lport) { |
| socklen_t len = sizeof(address); |
| getsockname(sfd, &address, &len); |
| fdprintf(2, "%d\n", SWAP_BE16(address.sin_port)); |
| } |
| repeatyness: |
| if ((cfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0) |
| bb_perror_msg_and_die("accept"); |
| |
| if (!execflag) close(sfd); |
| } else { |
| hostinfo = xgethostbyname(argv[optind]); |
| |
| address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list; |
| address.sin_port = bb_lookup_port(argv[optind+1], "tcp", 0); |
| |
| if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0) |
| bb_perror_msg_and_die("connect"); |
| cfd = sfd; |
| } |
| } |
| |
| if (wsecs) { |
| alarm(0); |
| signal(SIGALRM, SIG_DFL); |
| } |
| |
| /* -e given? */ |
| if (execflag) { |
| if(cfd) { |
| signal(SIGCHLD, SIG_IGN); |
| dup2(cfd, 0); |
| close(cfd); |
| } |
| dup2(0, 1); |
| dup2(0, 2); |
| |
| // With more than one -l, repeatedly act as server. |
| |
| if (do_listen>1 && vfork()) { |
| // 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. |
| close(0); |
| close(1); |
| close(2); |
| |
| goto repeatyness; |
| } |
| execvp(argv[optind], argv+optind); |
| /* 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 = xread(fd, bb_common_bufsiz1, sizeof(bb_common_bufsiz1)); |
| |
| if (fd == cfd) { |
| if (!nread) exit(0); |
| ofd = STDOUT_FILENO; |
| } else { |
| if (!nread) { |
| // 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; |
| } |
| |
| if (bb_full_write(ofd, bb_common_bufsiz1, nread) < 0) |
| bb_perror_msg_and_die(bb_msg_write_error); |
| if (delay > 0) sleep(delay); |
| } |
| } |
| } |
| } |