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 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
13 #include <sys/syslog.h>
17 #define IDENT_PORT 113
19 #define MAXIDLETIME 45
21 static const char ident_substr[] = " : USERID : UNIX : ";
22 enum { ident_substr_len = sizeof(ident_substr) - 1 };
23 #define PIDFILE "/var/run/identd.pid"
26 * We have to track the 'first connection socket' so that we
27 * don't go around closing file descriptors for non-clients.
29 * descriptor setup normally
31 * 1 = syslog fd (hopefully -- otherwise this won't work)
32 * 2 = connection socket after detached from tty. standard error before that
33 * 3 - 2 + MAXCONNS = rest connection sockets
35 * To try to make sure that syslog fd is what is "requested", the that fd
36 * is closed before openlog() call. It can only severely fail if fd 0
37 * is initially closed.
42 * FD of the connection is always the index of the connection structure
43 * in `conns' array + FCS
51 /* When using global variables, bind those at least to a structure. */
53 const char *identuser;
61 static void reply(int s, char *buf);
62 static void replyError(int s, char *buf);
64 static const char *nobodystr = "nobody"; /* this needs to be declared like this */
65 static char *bind_ip_address = "0.0.0.0";
67 static void movefd(int from, int to)
75 static void inetbind(void)
78 struct sockaddr_in addr;
79 int len = sizeof(addr);
83 if ((se = getservbyname("identd", "tcp")) == NULL)
88 s = xsocket(AF_INET, SOCK_STREAM, 0);
90 setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
92 memset(&addr, 0, sizeof(addr));
93 addr.sin_addr.s_addr = inet_addr(bind_ip_address);
94 addr.sin_family = AF_INET;
95 addr.sin_port = htons(port);
97 xbind(s, (struct sockaddr *)&addr, len);
103 static void handlexitsigs(int signum)
105 if (unlink(PIDFILE) < 0)
106 close(open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0644));
110 /* May succeed. If not, won't care. */
111 static void writepid(uid_t nobody, uid_t nogrp)
114 int fd = open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0664);
119 snprintf(buf, 23, "%d\n", getpid());
120 write(fd, buf, strlen(buf));
121 fchown(fd, nobody, nogrp);
124 /* should this handle ILL, ... (see signal(7)) */
125 signal(SIGTERM, handlexitsigs);
126 signal(SIGINT, handlexitsigs);
127 signal(SIGQUIT, handlexitsigs);
130 /* return 0 as parent, 1 as child */
131 static int godaemon(void)
138 bb_perror_msg_and_die("fork");
141 pw = getpwnam(nobodystr);
143 bb_error_msg_and_die("Cannot find uid/gid of user '%s'", nobodystr);
146 writepid(nobody, nogrp);
155 signal(SIGHUP, SIG_IGN);
156 signal(SIGPIPE, SIG_IGN); /* connection closed when writing (raises ???) */
166 static void deleteConn(int s)
175 * Most of the time there is 0 connections. Most often that there
176 * is connections, there is just one connection. When this one connection
177 * closes, i == G.conncnt = 0 -> no copying.
178 * When there is more than one connection, the oldest connections closes
179 * earlier on average. When this happens, the code below starts copying
180 * the connection structure w/ highest index to the place which which is
181 * just deleted. This means that the connection structures are no longer
182 * in chronological order. I'd quess this means that when there is more
183 * than 1 connection, on average every other connection structure needs
184 * to be copied over the time all these connections are deleted.
186 if (i != G.conncnt) {
187 memcpy(&conns[i], &conns[G.conncnt], sizeof(conns[0]));
188 movefd(G.conncnt + FCS, s);
191 FD_CLR(G.conncnt + FCS, &G.readfds);
194 static int closeOldest(void)
196 time_t min = conns[0].lasttime;
200 for (i = 1; i < MAXCONNS; i++)
201 if (conns[i].lasttime < min)
204 replyError(idx + FCS, "X-SERVER-TOO-BUSY");
210 static int checkInput(char *buf, int len, int l)
213 for (i = len; i < len + l; ++i)
219 int fakeidentd_main(int argc, char **argv)
221 /* This applet is an inetd-style daemon */
222 openlog(bb_applet_name, 0, LOG_DAEMON);
223 logmode = LOGMODE_SYSLOG;
225 memset(conns, 0, sizeof(conns));
226 memset(&G, 0, sizeof(G));
228 FD_SET(0, &G.readfds);
230 /* handle -b <ip> parameter */
231 bb_getopt_ulflags(argc, argv, "b:", &bind_ip_address);
232 /* handle optional REPLY STRING */
234 G.identuser = argv[optind];
236 G.identuser = nobodystr;
238 /* daemonize and have the parent return */
242 /* main loop where we process all events and never exit */
244 fd_set rfds = G.readfds;
245 struct timeval tv = { 15, 0 };
247 int tim = time(NULL);
249 select(G.conncnt + FCS, &rfds, NULL, NULL, G.conncnt? &tv: NULL);
251 for (i = G.conncnt - 1; i >= 0; i--) {
254 if (FD_ISSET(s, &rfds)) {
255 char *buf = conns[i].buf;
256 unsigned int len = conns[i].len;
259 if ((l = read(s, buf + len, sizeof(conns[0].buf) - len)) > 0) {
260 if (checkInput(buf, len, l)) {
263 } else if (len + l >= sizeof(conns[0].buf)) {
264 replyError(s, "X-INVALID-REQUEST");
273 conns[i].lasttime = tim;
279 /* implement as time_after() in linux kernel sources ... */
280 if (conns[i].lasttime + MAXIDLETIME <= tim) {
281 replyError(s, "X-TIMEOUT");
287 if (FD_ISSET(0, &rfds)) {
288 int s = accept(0, NULL, 0);
291 if (errno != EINTR) /* EINTR */
292 bb_perror_msg("accept");
294 if (G.conncnt == MAXCONNS)
299 movefd(s, i + FCS); /* move if not already there */
300 FD_SET(i + FCS, &G.readfds);
303 conns[i].lasttime = time(NULL);
306 } /* end of while(1) */
311 static int parseAddrs(char *ptr, char **myaddr, char **heraddr);
312 static void reply(int s, char *buf)
314 char *myaddr, *heraddr;
316 myaddr = heraddr = NULL;
318 if (parseAddrs(buf, &myaddr, &heraddr))
319 replyError(s, "X-INVALID-REQUEST");
322 iv[0].iov_base = myaddr; iv[0].iov_len = strlen(myaddr);
323 iv[1].iov_base = ", "; iv[1].iov_len = 2;
324 iv[2].iov_base = heraddr; iv[2].iov_len = strlen(heraddr);
325 iv[3].iov_base = (void *)ident_substr; iv[3].iov_len = ident_substr_len;
326 iv[4].iov_base = (void *)G.identuser; iv[4].iov_len = strlen(G.identuser);
327 iv[5].iov_base = "\r\n"; iv[5].iov_len = 2;
332 static void replyError(int s, char *buf)
335 iv[0].iov_base = "0, 0 : ERROR : "; iv[0].iov_len = 15;
336 iv[1].iov_base = buf; iv[1].iov_len = strlen(buf);
337 iv[2].iov_base = "\r\n"; iv[2].iov_len = 2;
341 static int chmatch(char c, char *chars)
343 for (; *chars; chars++)
349 static int skipchars(char **p, char *chars)
351 while (chmatch(**p, chars))
353 if (**p == '\r' || **p == '\n')
358 static int parseAddrs(char *ptr, char **myaddr, char **heraddr)
360 /* parse <port-on-server> , <port-on-client> */
362 if (!skipchars(&ptr, " \t"))
367 if (!skipchars(&ptr, "1234567890"))
370 if (!chmatch(*ptr, " \t,"))
375 if (!skipchars(&ptr, " \t,") )
380 skipchars(&ptr, "1234567890");
382 if (!chmatch(*ptr, " \n\r"))