bf155b3b13bb3148dd3fc11d94c4dac2cbb1c489
[people/mcb30/busybox.git] / networking / nc.c
1 /* vi: set sw=4 ts=4: */
2 /*  nc: mini-netcat - built from the ground up for LRP
3     Copyright (C) 1998  Charles P. Wright
4
5     0.0.1   6K      It works.
6     0.0.2   5K      Smaller and you can also check the exit condition if you wish.
7     0.0.3           Uses select()
8
9     19980918 Busy Boxed! Dave Cinege
10     19990512 Uses Select. Charles P. Wright
11     19990513 Fixes stdin stupidity and uses buffers.  Charles P. Wright
12
13     This program is free software; you can redistribute it and/or modify
14     it under the terms of the GNU General Public License as published by
15     the Free Software Foundation; either version 2 of the License, or
16     (at your option) any later version.
17
18     This program is distributed in the hope that it will be useful,
19     but WITHOUT ANY WARRANTY; without even the implied warranty of
20     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21     GNU General Public License for more details.
22
23     You should have received a copy of the GNU General Public License
24     along with this program; if not, write to the Free Software
25     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
26 */
27
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32 #include <signal.h>
33
34 #include <sys/types.h>
35 #include <sys/socket.h>
36 #include <netinet/in.h>
37 #include <arpa/inet.h>
38 #include <netdb.h>
39 #include <sys/time.h>
40 #include <sys/ioctl.h>
41 #include "busybox.h"
42
43 static void timeout(int signum)
44 {
45         bb_error_msg_and_die("Timed out");
46 }
47
48 int nc_main(int argc, char **argv)
49 {
50         int do_listen = 0, lport = 0, delay = 0, wsecs = 0, tmpfd, opt, sfd, x;
51         char buf[BUFSIZ];
52 #ifdef CONFIG_NC_GAPING_SECURITY_HOLE
53         char *pr00gie = NULL;
54 #endif
55
56         struct sockaddr_in address;
57         struct hostent *hostinfo;
58
59         fd_set readfds, testfds;
60
61         while ((opt = getopt(argc, argv, "lp:i:e:w:")) > 0) {
62                 switch (opt) {
63                         case 'l':
64                                 do_listen++;
65                                 break;
66                         case 'p':
67                                 lport = bb_lookup_port(optarg, "tcp", 0);
68                                 break;
69                         case 'i':
70                                 delay = atoi(optarg);
71                                 break;
72 #ifdef CONFIG_NC_GAPING_SECURITY_HOLE
73                         case 'e':
74                                 pr00gie = optarg;
75                                 break;
76 #endif
77                         case 'w':
78                                 wsecs = atoi(optarg);
79                                 break;
80                         default:
81                                 bb_show_usage();
82                 }
83         }
84
85 #ifdef CONFIG_NC_GAPING_SECURITY_HOLE
86         if (pr00gie) {
87                 /* won't need stdin */
88                 close(STDIN_FILENO);      
89         }
90 #endif /* CONFIG_NC_GAPING_SECURITY_HOLE */
91
92         if ((do_listen && optind != argc) || (!do_listen && optind + 2 != argc))
93                 bb_show_usage();
94
95         if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
96                 bb_perror_msg_and_die("socket");
97         x = 1;
98         if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof (x)) == -1)
99                 bb_perror_msg_and_die("reuseaddr");
100         address.sin_family = AF_INET;
101
102         if (wsecs) {
103                 signal(SIGALRM, timeout);
104                 alarm(wsecs);
105         }
106
107         if (lport != 0) {
108                 memset(&address.sin_addr, 0, sizeof(address.sin_addr));
109                 address.sin_port = lport;
110
111                 if (bind(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
112                         bb_perror_msg_and_die("bind");
113         }
114
115         if (do_listen) {
116                 socklen_t addrlen = sizeof(address);
117
118                 if (listen(sfd, 1) < 0)
119                         bb_perror_msg_and_die("listen");
120
121                 if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0)
122                         bb_perror_msg_and_die("accept");
123
124                 close(sfd);
125                 sfd = tmpfd;
126         } else {
127                 hostinfo = xgethostbyname(argv[optind]);
128
129                 address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
130                 address.sin_port = bb_lookup_port(argv[optind+1], "tcp", 0);
131
132                 if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
133                         bb_perror_msg_and_die("connect");
134         }
135
136         if (wsecs) {
137                 alarm(0);
138                 signal(SIGALRM, SIG_DFL);
139         }
140
141 #ifdef CONFIG_NC_GAPING_SECURITY_HOLE
142         /* -e given? */
143         if (pr00gie) {
144                 dup2(sfd, 0);
145                 close(sfd);
146                 dup2(0, 1);
147                 dup2(0, 2);
148                 execl(pr00gie, pr00gie, NULL);
149                 /* Don't print stuff or it will go over the wire.... */
150                 _exit(-1);
151         }
152 #endif /* CONFIG_NC_GAPING_SECURITY_HOLE */
153
154         FD_ZERO(&readfds);
155         FD_SET(sfd, &readfds);
156         FD_SET(STDIN_FILENO, &readfds);
157
158         while (1) {
159                 int fd;
160                 int ofd;
161                 int nread;
162
163                 testfds = readfds;
164
165                 if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0)
166                         bb_perror_msg_and_die("select");
167
168                 for (fd = 0; fd < FD_SETSIZE; fd++) {
169                         if (FD_ISSET(fd, &testfds)) {
170                                 if ((nread = safe_read(fd, buf, sizeof(buf))) < 0)
171                                         bb_perror_msg_and_die(bb_msg_read_error);
172
173                                 if (fd == sfd) {
174                                         if (nread == 0)
175                                                 exit(0);
176                                         ofd = STDOUT_FILENO;
177                                 } else {
178                                         if (nread <= 0) {
179                                                 shutdown(sfd, 1 /* send */ );
180                                                 close(STDIN_FILENO);
181                                                 FD_CLR(STDIN_FILENO, &readfds);
182                                         }
183                                         ofd = sfd;
184                                 }
185
186                                 if (bb_full_write(ofd, buf, nread) < 0)
187                                         bb_perror_msg_and_die(bb_msg_write_error);
188                                 if (delay > 0) {
189                                         sleep(delay);
190                                 }
191                         }
192                 }
193         }
194 }