/* vi: set sw=4 ts=4: */
-/* nc: mini-netcat - built from the ground up for LRP
- Copyright (C) 1998 Charles P. Wright
-
- 0.0.1 6K It works.
- 0.0.2 5K Smaller and you can also check the exit condition if you wish.
- 0.0.3 Uses select()
-
- 19980918 Busy Boxed! Dave Cinege
- 19990512 Uses Select. Charles P. Wright
- 19990513 Fixes stdin stupidity and uses buffers. Charles P. Wright
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
-
-*/
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#include <netdb.h>
-#include <sys/time.h>
-#include <sys/ioctl.h>
-#include "busybox.h"
-
-#define GAPING_SECURITY_HOLE
+/* 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)
{
- int do_listen = 0, lport = 0, delay = 0, tmpfd, opt, sfd, x;
- char buf[BUFSIZ];
-#ifdef GAPING_SECURITY_HOLE
- char * pr00gie = NULL;
-#endif
-
- struct sockaddr_in address;
- struct hostent *hostinfo;
-
+ /* 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;
-
- while ((opt = getopt(argc, argv, "lp:i:e:")) > 0) {
- switch (opt) {
- case 'l':
- do_listen++;
- break;
- case 'p':
- lport = atoi(optarg);
- break;
- case 'i':
- delay = atoi(optarg);
- break;
-#ifdef GAPING_SECURITY_HOLE
- case 'e':
- pr00gie = optarg;
- break;
-#endif
- default:
- show_usage();
+ 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++;
}
-#ifdef GAPING_SECURITY_HOLE
- if (pr00gie) {
- /* won't need stdin */
- close (fileno(stdin));
+ if (wsecs) {
+ signal(SIGALRM, timeout);
+ alarm(wsecs);
}
-#endif /* GAPING_SECURITY_HOLE */
-
-
- if ((do_listen && optind != argc) || (!do_listen && optind + 2 != argc))
- show_usage();
-
- if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
- perror_msg_and_die("socket");
- x = 1;
- if (setsockopt (sfd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof (x)) == -1)
- perror_msg_and_die ("reuseaddr failed");
- address.sin_family = AF_INET;
-
- if (lport != 0) {
- memset(&address.sin_addr, 0, sizeof(address.sin_addr));
- address.sin_port = htons(lport);
- if (bind(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
- perror_msg_and_die("bind");
+ 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 (do_listen) {
- socklen_t addrlen = sizeof(address);
-
- if (listen(sfd, 1) < 0)
- perror_msg_and_die("listen");
-
- if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0)
- perror_msg_and_die("accept");
-
- close(sfd);
- sfd = tmpfd;
- } else {
- hostinfo = xgethostbyname(argv[optind]);
-
- address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
- address.sin_port = htons(atoi(argv[optind+1]));
-
- if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
- perror_msg_and_die("connect");
+ if (wsecs) {
+ alarm(0);
+ /* Non-ignored signals revert to SIG_DFL on exec anyway */
+ /*signal(SIGALRM, SIG_DFL);*/
}
-#ifdef GAPING_SECURITY_HOLE
/* -e given? */
- if (pr00gie) {
- dup2(sfd, 0);
- close(sfd);
- dup2 (0, 1);
- dup2 (0, 2);
- execl (pr00gie, pr00gie, NULL);
- /* Don't print stuff or it will go over the wire.... */
- _exit(-1);
+ 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]);)
}
-#endif /* GAPING_SECURITY_HOLE */
+ /* Select loop copying stdin to cfd, and cfd to stdout */
FD_ZERO(&readfds);
- FD_SET(sfd, &readfds);
+ FD_SET(cfd, &readfds);
FD_SET(STDIN_FILENO, &readfds);
- while (1) {
+#define iobuf bb_common_bufsiz1
+ setup_common_bufsiz();
+ for (;;) {
int fd;
int ofd;
int nread;
testfds = readfds;
- if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0)
- perror_msg_and_die("select");
+ if (select(cfd + 1, &testfds, NULL, NULL, NULL) < 0)
+ bb_perror_msg_and_die("select");
- for (fd = 0; fd < FD_SETSIZE; fd++) {
+ fd = STDIN_FILENO;
+ while (1) {
if (FD_ISSET(fd, &testfds)) {
- if ((nread = safe_read(fd, buf, sizeof(buf))) < 0)
- perror_msg_and_die("read");
-
- if (fd == sfd) {
- if (nread == 0)
- exit(0);
+ nread = safe_read(fd, iobuf, COMMON_BUFSIZE);
+ if (fd == cfd) {
+ if (nread < 1)
+ exit(EXIT_SUCCESS);
ofd = STDOUT_FILENO;
} else {
- if (nread == 0)
- shutdown(sfd, 1);
- ofd = sfd;
+ 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;
}
-
- if (full_write(ofd, buf, nread) < 0)
- perror_msg_and_die("write");
- if (delay > 0) {
+ xwrite(ofd, iobuf, nread);
+ if (delay > 0)
sleep(delay);
- }
}
+ if (fd == cfd)
+ break;
+ fd = cfd;
}
}
}
+#endif
projects / oweals / busybox.git / blobdiff