hush/nc.c

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/* vi: set sw=4 ts=4: */
/* nc: mini-netcat - built from the ground up for LRP
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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.
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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
19990513 Fixes stdin stupidity and uses buffers. Charles P. Wright
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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 "busybox.h"
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#include <stdio.h>
#include <stdlib.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>
int nc_main(int argc, char **argv)
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{
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int do_listen = 0, lport = 0, tmpfd, opt, sfd;
char buf[BUFSIZ];
struct sockaddr_in address;
struct hostent *hostinfo;
fd_set readfds, testfds;
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while ((opt = getopt(argc, argv, "lp:")) > 0) {
switch (opt) {
case 'l':
do_listen++;
break;
case 'p':
lport = atoi(optarg);
break;
default:
usage(nc_usage);
}
}
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if ((do_listen && optind != argc) || (!do_listen && optind + 2 != argc))
usage(nc_usage);
if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
perror_msg_and_die("socket");
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address.sin_family = AF_INET;
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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 (do_listen) {
if (listen(sfd, 1) < 0)
perror_msg_and_die("listen");
if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &opt)) < 0)
perror_msg_and_die("accept");
close(sfd);
sfd = tmpfd;
} else {
if ((hostinfo = gethostbyname(argv[optind])) == NULL)
error_msg_and_die("cannot resolve %s\n", 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");
}
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FD_ZERO(&readfds);
FD_SET(sfd, &readfds);
FD_SET(STDIN_FILENO, &readfds);
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while (1) {
int fd;
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int ofd;
int nread;
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testfds = readfds;
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if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0)
perror_msg_and_die("select");
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for (fd = 0; fd < FD_SETSIZE; fd++) {
if (FD_ISSET(fd, &testfds)) {
if ((nread = safe_read(fd, buf, sizeof(buf))) < 0)
perror_msg_and_die("read");
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if (fd == sfd) {
if (nread == 0)
exit(0);
ofd = STDOUT_FILENO;
} else {
if (nread == 0)
shutdown(sfd, 1);
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ofd = sfd;
}
if (full_write(ofd, buf, nread) < 0)
perror_msg_and_die("write");
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}
}
}
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}