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/* 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"
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 = safe_read(fd, bb_common_bufsiz1,
sizeof(bb_common_bufsiz1));
if (fd == cfd) {
if (nread<1) exit(0);
ofd = STDOUT_FILENO;
} else {
if (nread<1) {
// 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;
}
xwrite(ofd, bb_common_bufsiz1, nread);
if (delay > 0) sleep(delay);
}
}
}
}
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