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Upgrade netcat a lot. Make -e able to take the rest of the command line as

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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
2006-07-10 19:45:20 +00:00
parent 5d8843e451
commit 1cca9484db
4 changed files with 146 additions and 117 deletions
Download Patch File Download Diff File Expand all files Collapse all files

204
networking/nc.c
View File

@@ -1,32 +1,16 @@
/* vi: set sw=4 ts=4: */
/* nc: mini-netcat - built from the ground up for LRP
Copyright (C) 1998 Charles P. Wright
*
* 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.
*/
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
Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/ioctl.h>
#include "busybox.h"
#define xread bb_xread
static void timeout(int signum)
{
bb_error_msg_and_die("Timed out");
@@ -34,79 +18,87 @@ static void timeout(int signum)
int nc_main(int argc, char **argv)
{
int do_listen = 0, lport = 0, delay = 0, wsecs = 0, tmpfd, opt, sfd, x;
#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
char *pr00gie = NULL;
#endif
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;
while ((opt = getopt(argc, argv, "lp:i:e:w:")) > 0) {
switch (opt) {
case 'l':
do_listen++;
break;
case 'p':
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;
case 'i':
delay = atoi(optarg);
break;
#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
case 'e':
pr00gie = optarg;
break;
#endif
case 'w':
wsecs = atoi(optarg);
break;
default:
bb_show_usage();
} else bb_show_usage();
}
}
if ((do_listen && optind != argc) || (!do_listen && optind + 2 != argc))
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
sfd = bb_xsocket(AF_INET, SOCK_STREAM, 0);
x = 1;
if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof (x)) == -1)
bb_perror_msg_and_die("reuseaddr");
address.sin_family = AF_INET;
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;
if (lport != 0) {
memset(&address.sin_addr, 0, sizeof(address.sin_addr));
address.sin_port = lport;
// Set local port.
bb_xbind(sfd, (struct sockaddr *) &address, sizeof(address));
}
if (lport != 0) {
address.sin_port = lport;
if (do_listen) {
socklen_t addrlen = sizeof(address);
bb_xbind(sfd, (struct sockaddr *) &address, sizeof(address));
}
bb_xlisten(sfd, 1);
if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0)
bb_perror_msg_and_die("accept");
if (do_listen) {
socklen_t addrlen = sizeof(address);
close(sfd);
sfd = tmpfd;
} else {
hostinfo = xgethostbyname(argv[optind]);
bb_xlisten(sfd, do_listen);
address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
address.sin_port = bb_lookup_port(argv[optind+1], "tcp", 0);
// If we didn't specify a port number, query and print it to stderr.
if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
bb_perror_msg_and_die("connect");
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) {
@@ -114,24 +106,40 @@ int nc_main(int argc, char **argv)
signal(SIGALRM, SIG_DFL);
}
#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
/* -e given? */
if (pr00gie) {
dup2(sfd, 0);
close(sfd);
if (execflag) {
if(cfd) {
signal(SIGCHLD, SIG_IGN);
dup2(cfd, 0);
close(cfd);
}
dup2(0, 1);
dup2(0, 2);
execl(pr00gie, pr00gie, NULL);
/* Don't print stuff or it will go over the wire.... */
_exit(-1);
}
#endif /* CONFIG_NC_GAPING_SECURITY_HOLE */
// 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(sfd, &readfds);
FD_SET(cfd, &readfds);
FD_SET(STDIN_FILENO, &readfds);
while (1) {
for (;;) {
int fd;
int ofd;
int nread;
@@ -143,30 +151,24 @@ int nc_main(int argc, char **argv)
for (fd = 0; fd < FD_SETSIZE; fd++) {
if (FD_ISSET(fd, &testfds)) {
if ((nread = safe_read(fd, bb_common_bufsiz1,
sizeof(bb_common_bufsiz1))) < 0)
{
bb_perror_msg_and_die(bb_msg_read_error);
}
nread = xread(fd, bb_common_bufsiz1, sizeof(bb_common_bufsiz1));
if (fd == sfd) {
if (nread == 0)
exit(0);
if (fd == cfd) {
if (!nread) exit(0);
ofd = STDOUT_FILENO;
} else {
if (nread <= 0) {
shutdown(sfd, 1 /* send */ );
close(STDIN_FILENO);
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 = sfd;
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);
}
if (delay > 0) sleep(delay);
}
}
}