1 /* vi: set sw=4 ts=4: */
5 * Adapted to busybox by Thomas Lundquist <thomasez@zelow.no>
6 * Original Author: Tomi Ollila <too@iki.fi>
7 * http://www.guru-group.fi/~too/sw/
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
32 #include <sys/syslog.h>
37 #include <sys/syslog.h>
38 #include <sys/types.h>
41 #include <sys/socket.h>
42 #include <netinet/in.h>
44 #include <arpa/inet.h>
49 #define IDENT_PORT 113
51 #define MAXIDLETIME 45
53 static const char ident_substr[] = " : USERID : UNIX : ";
54 static const int ident_substr_len = sizeof(ident_substr) - 1;
55 #define PIDFILE "/var/run/identd.pid"
58 * We have to track the 'first connection socket' so that we
59 * don't go around closing file descriptors for non-clients.
61 * descriptor setup normally
63 * 1 = syslog fd (hopefully -- otherwise this won't work)
64 * 2 = connection socket after detached from tty. standard error before that
65 * 3 - 2 + MAXCONNS = rest connection sockets
67 * To try to make sure that syslog fd is what is "requested", the that fd
68 * is closed before openlog() call. It can only severely fail if fd 0
69 * is initially closed.
74 * FD of the connection is always the index of the connection structure
75 * in `conns' array + FCS
83 /* When using global variables, bind those at least to a structure. */
85 const char *identuser;
93 static void reply(int s, char *buf);
94 static void replyError(int s, char *buf);
96 static const char *nobodystr = "nobody"; /* this needs to be declared like this */
97 static char *bind_ip_address = "0.0.0.0";
99 static inline void movefd(int from, int to)
107 static void inetbind(void)
110 struct sockaddr_in addr;
111 int len = sizeof(addr);
115 if ((se = getservbyname("identd", "tcp")) == NULL)
120 if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0)
121 bb_perror_msg_and_die("Cannot create server socket");
123 setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
125 memset(&addr, 0, sizeof(addr));
126 addr.sin_addr.s_addr = inet_addr(bind_ip_address);
127 addr.sin_family = AF_INET;
128 addr.sin_port = htons(port);
130 if (bind(s, (struct sockaddr *)&addr, len) < 0)
131 bb_perror_msg_and_die("Cannot bind() port %i", IDENT_PORT);
133 if (listen(s, 5) < 0)
134 bb_perror_msg_and_die("Cannot listen() on port %i", IDENT_PORT);
139 static void handlexitsigs(int signum)
141 if (unlink(PIDFILE) < 0)
142 close(open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0644));
146 /* May succeed. If not, won't care. */
147 static inline void writepid(uid_t nobody, uid_t nogrp)
150 int fd = open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0664);
155 snprintf(buf, 23, "%d\n", getpid());
156 write(fd, buf, strlen(buf));
157 fchown(fd, nobody, nogrp);
160 /* should this handle ILL, ... (see signal(7)) */
161 signal(SIGTERM, handlexitsigs);
162 signal(SIGINT, handlexitsigs);
163 signal(SIGQUIT, handlexitsigs);
166 /* return 0 as parent, 1 as child */
167 static int godaemon(void)
174 bb_perror_msg_and_die("Could not fork");
177 pw = getpwnam(nobodystr);
179 bb_error_msg_and_die("Cannot find uid/gid of user '%s'", nobodystr);
182 writepid(nobody, nogrp);
186 if (setgid(nogrp)) bb_error_msg_and_die("Could not setgid()");
187 if (setegid(nogrp)) bb_error_msg_and_die("Could not setegid()");
188 if (setuid(nobody)) bb_error_msg_and_die("Could not setuid()");
189 if (seteuid(nobody)) bb_error_msg_and_die("Could not seteuid()");
193 signal(SIGHUP, SIG_IGN);
194 signal(SIGPIPE, SIG_IGN); /* connection closed when writing (raises ???) */
198 openlog(bb_applet_name, 0, LOG_DAEMON);
205 static void deleteConn(int s)
214 * Most of the time there is 0 connections. Most often that there
215 * is connections, there is just one connection. When this one connection
216 * closes, i == G.conncnt = 0 -> no copying.
217 * When there is more than one connection, the oldest connections closes
218 * earlier on average. When this happens, the code below starts copying
219 * the connection structure w/ highest index to the place which which is
220 * just deleted. This means that the connection structures are no longer
221 * in chronological order. I'd quess this means that when there is more
222 * than 1 connection, on average every other connection structure needs
223 * to be copied over the time all these connections are deleted.
225 if (i != G.conncnt) {
226 memcpy(&conns[i], &conns[G.conncnt], sizeof(conns[0]));
227 movefd(G.conncnt + FCS, s);
230 FD_CLR(G.conncnt + FCS, &G.readfds);
233 static int closeOldest(void)
235 time_t min = conns[0].lasttime;
239 for (i = 1; i < MAXCONNS; i++)
240 if (conns[i].lasttime < min)
243 replyError(idx + FCS, "X-SERVER-TOO-BUSY");
249 static int checkInput(char *buf, int len, int l)
252 for (i = len; i < len + l; ++i)
258 int fakeidentd_main(int argc, char **argv)
260 memset(conns, 0, sizeof(conns));
261 memset(&G, 0, sizeof(G));
263 FD_SET(0, &G.readfds);
265 /* handle -b <ip> parameter */
266 bb_getopt_ulflags(argc, argv, "b:", &bind_ip_address);
267 /* handle optional REPLY STRING */
269 G.identuser = argv[optind];
271 G.identuser = nobodystr;
273 /* daemonize and have the parent return */
277 /* main loop where we process all events and never exit */
279 fd_set rfds = G.readfds;
280 struct timeval tv = { 15, 0 };
282 int tim = time(NULL);
284 select(G.conncnt + FCS, &rfds, NULL, NULL, G.conncnt? &tv: NULL);
286 for (i = G.conncnt - 1; i >= 0; i--) {
289 if (FD_ISSET(s, &rfds)) {
290 char *buf = conns[i].buf;
291 unsigned int len = conns[i].len;
294 if ((l = read(s, buf + len, sizeof(conns[0].buf) - len)) > 0) {
295 if (checkInput(buf, len, l)) {
298 } else if (len + l >= sizeof(conns[0].buf)) {
299 replyError(s, "X-INVALID-REQUEST");
308 conns[i].lasttime = tim;
314 /* implement as time_after() in linux kernel sources ... */
315 if (conns[i].lasttime + MAXIDLETIME <= tim) {
316 replyError(s, "X-TIMEOUT");
322 if (FD_ISSET(0, &rfds)) {
323 int s = accept(0, NULL, 0);
326 if (errno != EINTR) /* EINTR */
327 syslog(LOG_ERR, "accept: %s", strerror(errno));
329 if (G.conncnt == MAXCONNS)
334 movefd(s, i + FCS); /* move if not already there */
335 FD_SET(i + FCS, &G.readfds);
338 conns[i].lasttime = time(NULL);
341 } /* end of while(1) */
346 static int parseAddrs(char *ptr, char **myaddr, char **heraddr);
347 static void reply(int s, char *buf)
349 char *myaddr, *heraddr;
351 myaddr = heraddr = NULL;
353 if (parseAddrs(buf, &myaddr, &heraddr))
354 replyError(s, "X-INVALID-REQUEST");
357 iv[0].iov_base = myaddr; iv[0].iov_len = strlen(myaddr);
358 iv[1].iov_base = ", "; iv[1].iov_len = 2;
359 iv[2].iov_base = heraddr; iv[2].iov_len = strlen(heraddr);
360 iv[3].iov_base = (void *)ident_substr; iv[3].iov_len = ident_substr_len;
361 iv[4].iov_base = (void *)G.identuser; iv[4].iov_len = strlen(G.identuser);
362 iv[5].iov_base = "\r\n"; iv[5].iov_len = 2;
367 static void replyError(int s, char *buf)
370 iv[0].iov_base = "0, 0 : ERROR : "; iv[0].iov_len = 15;
371 iv[1].iov_base = buf; iv[1].iov_len = strlen(buf);
372 iv[2].iov_base = "\r\n"; iv[2].iov_len = 2;
376 static int chmatch(char c, char *chars)
378 for (; *chars; chars++)
384 static int skipchars(char **p, char *chars)
386 while (chmatch(**p, chars))
388 if (**p == '\r' || **p == '\n')
393 static int parseAddrs(char *ptr, char **myaddr, char **heraddr)
395 /* parse <port-on-server> , <port-on-client> */
397 if (!skipchars(&ptr, " \t"))
402 if (!skipchars(&ptr, "1234567890"))
405 if (!chmatch(*ptr, " \t,"))
410 if (!skipchars(&ptr, " \t,") )
415 skipchars(&ptr, "1234567890");
417 if (!chmatch(*ptr, " \n\r"))