Upgrade netcat a lot. Make -e able to take the rest of the command line as
what to exec. Add -f mode and a brief explanation of how to use it to replace minicom. Add -l -l mode so you can turn any command into a server. And group all of netcat's command line options under two CONFIG entries, so if you disable both it doesn't use getopt at all.
This commit is contained in:
Rob Landley
parent
5d8843e451
commit
1cca9484db
@ -19,6 +19,7 @@
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#include <fcntl.h>
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#include <inttypes.h>
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#include <netdb.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdarg.h>
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@ -2105,23 +2105,41 @@ USE_FEATURE_MDEV_CONFIG( \
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" or\n" \
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"$ nameif -c /etc/my_mactab_file\n" \
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#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
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# define USAGE_NC_EXEC(a) a
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#if ENABLE_NC_SERVER || ENABLE_NC_EXTRA
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#define NC_BR1 "["
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#define NC_BR2 "]"
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#else
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# define USAGE_NC_EXEC(a)
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#define NC_BR1
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#define NC_BR2
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#endif
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#define nc_trivial_usage \
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"[OPTIONS] [IP] [port]"
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"[" \
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NC_BR1 USE_NC_SERVER("-lp")USE_NC_EXTRA("iwf") NC_BR2 \
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" ["USE_NC_EXTRA("FILENAME|")"{IPADDR PORTNUM}]"USE_NC_EXTRA(" [-e COMMAND]")
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#define nc_full_usage \
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"Netcat opens a pipe to IP:port\n\n" \
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"Options:\n" \
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"\t-l\t\tlisten mode, for inbound connects\n" \
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"\t-p PORT\t\tlocal port number\n" \
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"\t-i SECS\t\tdelay interval for lines sent\n" \
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USAGE_NC_EXEC( \
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"\t-e PROG\t\tprogram to exec after connect (dangerous!)\n" \
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"Netcat opens a pipe, either to IP:port\n\n" \
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"Options:" \
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USE_NC_EXTRA( \
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"\n\t-e\t\texec rest of command line after connect\n" \
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"\t-i SECS\t\tdelay interval for lines sent\n" \
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"\t-w SECS\t\ttimeout for connect\n" \
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"\t-f filename\tuse file (ala /dev/ttyS0) instead of network" \
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) \
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"\t-w SECS\t\ttimeout for connects and final net reads"
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USE_NC_SERVER( \
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"\n\t-l\t\tlisten mode, for inbound connects\n" \
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USE_NC_EXTRA("\t\t\t(use -l twice with -e for persistent server)\n") \
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"\t-p PORT\t\tlocal port number" \
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)
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#define nc_notes_usage "" \
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USE_NC_EXTRA( \
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"To use netcat as a terminal emulator on a serial port:\n\n" \
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"$ stty 115200 -F /dev/ttyS0\n" \
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"$ stty raw -echo -ctlecho && nc -f /dev/ttyS0\n" \
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) ""
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#define nc_example_usage \
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"$ nc foobar.somedomain.com 25\n" \
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"220 foobar ESMTP Exim 3.12 #1 Sat, 15 Apr 2000 00:03:02 -0600\n" \
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@ -446,13 +446,21 @@ config CONFIG_NC
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A simple Unix utility which reads and writes data across network
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connections.
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config CONFIG_NC_GAPING_SECURITY_HOLE
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bool "gaping security hole"
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config CONFIG_NC_SERVER
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bool "Netcat server options (-lp)"
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default n
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depends on CONFIG_NC
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help
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Add support for executing a program after making or receiving a
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successful connection (-e option).
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Allow netcat to act as a server.
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config CONFIG_NC_EXTRA
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bool "Netcat extensions (-eiw and filename)"
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default n
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depends on CONFIG_NC
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help
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Add -e (support for executing the rest of the command line after
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making or receiving a successful connection), -i (delay interval for
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lines sent), -w (timeout for initial connection).
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config CONFIG_NETSTAT
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bool "netstat"
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200
networking/nc.c
200
networking/nc.c
@ -1,32 +1,16 @@
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/* vi: set sw=4 ts=4: */
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/* nc: mini-netcat - built from the ground up for LRP
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Copyright (C) 1998 Charles P. Wright
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*
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* Copyright (C) 1998, 1999 Charles P. Wright
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* Copyright (C) 1998 Dave Cinege
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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0.0.1 6K It works.
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0.0.2 5K Smaller and you can also check the exit condition if you wish.
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0.0.3 Uses select()
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19980918 Busy Boxed! Dave Cinege
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19990512 Uses Select. Charles P. Wright
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19990513 Fixes stdin stupidity and uses buffers. Charles P. Wright
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Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <sys/ioctl.h>
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#include "busybox.h"
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#define xread bb_xread
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static void timeout(int signum)
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{
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bb_error_msg_and_die("Timed out");
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@ -34,79 +18,87 @@ static void timeout(int signum)
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int nc_main(int argc, char **argv)
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{
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int do_listen = 0, lport = 0, delay = 0, wsecs = 0, tmpfd, opt, sfd, x;
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#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
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char *pr00gie = NULL;
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#endif
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int do_listen = 0, lport = 0, delay = 0, wsecs = 0, execflag = 0, opt,
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sfd = 0, cfd;
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struct sockaddr_in address;
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struct hostent *hostinfo;
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fd_set readfds, testfds;
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char *infile = NULL;
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while ((opt = getopt(argc, argv, "lp:i:e:w:")) > 0) {
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switch (opt) {
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case 'l':
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do_listen++;
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break;
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case 'p':
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memset(&address, 0, sizeof(address));
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if (ENABLE_NC_SERVER || ENABLE_NC_EXTRA) {
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while ((opt = getopt(argc, argv, "lp:" USE_NC_EXTRA("i:ew:f:"))) > 0) {
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if (ENABLE_NC_SERVER && opt=='l') do_listen++;
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else if (ENABLE_NC_SERVER && opt=='p')
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lport = bb_lookup_port(optarg, "tcp", 0);
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else if (ENABLE_NC_EXTRA && opt=='w') wsecs = atoi(optarg);
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else if (ENABLE_NC_EXTRA && opt=='i') delay = atoi(optarg);
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else if (ENABLE_NC_EXTRA && opt=='f') infile = optarg;
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else if (ENABLE_NC_EXTRA && opt=='e' && optind!=argc) {
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execflag++;
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break;
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case 'i':
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delay = atoi(optarg);
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break;
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#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
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case 'e':
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pr00gie = optarg;
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break;
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#endif
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case 'w':
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wsecs = atoi(optarg);
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break;
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default:
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bb_show_usage();
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} else bb_show_usage();
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}
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}
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if ((do_listen && optind != argc) || (!do_listen && optind + 2 != argc))
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bb_show_usage();
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sfd = bb_xsocket(AF_INET, SOCK_STREAM, 0);
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x = 1;
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if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof (x)) == -1)
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bb_perror_msg_and_die("reuseaddr");
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address.sin_family = AF_INET;
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// For listen or file we need zero arguments, dialout is 2.
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// For exec we need at least one more argument at the end, more ok
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opt = (do_listen || infile) ? 0 : 2 + execflag;
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if (execflag ? argc-optind < opt : argc-optind!=opt ||
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(infile && do_listen))
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bb_show_usage();
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if (wsecs) {
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signal(SIGALRM, timeout);
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alarm(wsecs);
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}
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if (lport != 0) {
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memset(&address.sin_addr, 0, sizeof(address.sin_addr));
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address.sin_port = lport;
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if (infile) cfd = bb_xopen(infile, O_RDWR);
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else {
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opt = 1;
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sfd = bb_xsocket(AF_INET, SOCK_STREAM, 0);
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fcntl(sfd, F_SETFD, FD_CLOEXEC);
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setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof (opt));
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address.sin_family = AF_INET;
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bb_xbind(sfd, (struct sockaddr *) &address, sizeof(address));
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}
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// Set local port.
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if (do_listen) {
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socklen_t addrlen = sizeof(address);
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if (lport != 0) {
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address.sin_port = lport;
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bb_xlisten(sfd, 1);
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if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0)
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bb_perror_msg_and_die("accept");
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bb_xbind(sfd, (struct sockaddr *) &address, sizeof(address));
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}
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close(sfd);
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sfd = tmpfd;
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} else {
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hostinfo = xgethostbyname(argv[optind]);
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if (do_listen) {
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socklen_t addrlen = sizeof(address);
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address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
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address.sin_port = bb_lookup_port(argv[optind+1], "tcp", 0);
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bb_xlisten(sfd, do_listen);
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if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
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bb_perror_msg_and_die("connect");
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// If we didn't specify a port number, query and print it to stderr.
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if (!lport) {
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socklen_t len = sizeof(address);
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getsockname(sfd, &address, &len);
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fdprintf(2, "%d\n", SWAP_BE16(address.sin_port));
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}
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repeatyness:
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if ((cfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0)
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bb_perror_msg_and_die("accept");
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if (!execflag) close(sfd);
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} else {
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hostinfo = xgethostbyname(argv[optind]);
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address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
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address.sin_port = bb_lookup_port(argv[optind+1], "tcp", 0);
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if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
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bb_perror_msg_and_die("connect");
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cfd = sfd;
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}
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}
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if (wsecs) {
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@ -114,24 +106,40 @@ int nc_main(int argc, char **argv)
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signal(SIGALRM, SIG_DFL);
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}
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#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
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/* -e given? */
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if (pr00gie) {
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dup2(sfd, 0);
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close(sfd);
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if (execflag) {
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if(cfd) {
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signal(SIGCHLD, SIG_IGN);
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dup2(cfd, 0);
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close(cfd);
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}
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dup2(0, 1);
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dup2(0, 2);
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execl(pr00gie, pr00gie, NULL);
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// With more than one -l, repeatedly act as server.
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if (do_listen>1 && vfork()) {
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// This is a bit weird as cleanup goes, since we wind up with no
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// stdin/stdout/stderr. But it's small and shouldn't hurt anything.
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// We check for cfd == 0 above.
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close(0);
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close(1);
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close(2);
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goto repeatyness;
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}
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execvp(argv[optind], argv+optind);
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/* Don't print stuff or it will go over the wire.... */
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_exit(-1);
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_exit(127);
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}
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#endif /* CONFIG_NC_GAPING_SECURITY_HOLE */
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// Select loop copying stdin to cfd, and cfd to stdout.
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FD_ZERO(&readfds);
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FD_SET(sfd, &readfds);
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FD_SET(cfd, &readfds);
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FD_SET(STDIN_FILENO, &readfds);
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while (1) {
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for (;;) {
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int fd;
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int ofd;
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int nread;
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@ -143,30 +151,24 @@ int nc_main(int argc, char **argv)
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for (fd = 0; fd < FD_SETSIZE; fd++) {
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if (FD_ISSET(fd, &testfds)) {
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if ((nread = safe_read(fd, bb_common_bufsiz1,
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sizeof(bb_common_bufsiz1))) < 0)
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{
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bb_perror_msg_and_die(bb_msg_read_error);
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}
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nread = xread(fd, bb_common_bufsiz1, sizeof(bb_common_bufsiz1));
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if (fd == sfd) {
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if (nread == 0)
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exit(0);
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if (fd == cfd) {
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if (!nread) exit(0);
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ofd = STDOUT_FILENO;
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} else {
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if (nread <= 0) {
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shutdown(sfd, 1 /* send */ );
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close(STDIN_FILENO);
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if (!nread) {
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// Close outgoing half-connection so they get EOF, but
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// leave incoming alone so we can see response.
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shutdown(cfd, 1);
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FD_CLR(STDIN_FILENO, &readfds);
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}
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ofd = sfd;
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ofd = cfd;
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}
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if (bb_full_write(ofd, bb_common_bufsiz1, nread) < 0)
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bb_perror_msg_and_die(bb_msg_write_error);
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if (delay > 0) {
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sleep(delay);
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}
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if (delay > 0) sleep(delay);
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}
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}
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}
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Loading…
Reference in New Issue
Block a user