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.
19 #include <sys/syslog.h>
24 #include <sys/syslog.h>
25 #include <sys/types.h>
27 #include <sys/socket.h>
28 #include <netinet/in.h>
30 #include <arpa/inet.h>
35 #define IDENT_PORT 113
37 #define MAXIDLETIME 45
39 static const char ident_substr[] = " : USERID : UNIX : ";
40 enum { ident_substr_len = sizeof(ident_substr) - 1 };
41 #define PIDFILE "/var/run/identd.pid"
44 * We have to track the 'first connection socket' so that we
45 * don't go around closing file descriptors for non-clients.
47 * descriptor setup normally
49 * 1 = syslog fd (hopefully -- otherwise this won't work)
50 * 2 = connection socket after detached from tty. standard error before that
51 * 3 - 2 + MAXCONNS = rest connection sockets
53 * To try to make sure that syslog fd is what is "requested", the that fd
54 * is closed before openlog() call. It can only severely fail if fd 0
55 * is initially closed.
60 * FD of the connection is always the index of the connection structure
61 * in `conns' array + FCS
69 /* When using global variables, bind those at least to a structure. */
71 const char *identuser;
79 static void reply(int s, char *buf);
80 static void replyError(int s, char *buf);
82 static const char *nobodystr = "nobody"; /* this needs to be declared like this */
83 static char *bind_ip_address = "0.0.0.0";
85 static inline void movefd(int from, int to)
93 static void inetbind(void)
96 struct sockaddr_in addr;
97 int len = sizeof(addr);
101 if ((se = getservbyname("identd", "tcp")) == NULL)
106 s = bb_xsocket(AF_INET, SOCK_STREAM, 0);
108 setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
110 memset(&addr, 0, sizeof(addr));
111 addr.sin_addr.s_addr = inet_addr(bind_ip_address);
112 addr.sin_family = AF_INET;
113 addr.sin_port = htons(port);
115 if (bind(s, (struct sockaddr *)&addr, len) < 0) /* bb_xbind? */
116 bb_perror_msg_and_die("Cannot bind() port %i", IDENT_PORT);
118 if (listen(s, 5) < 0) /* bb_xlisten? */
119 bb_perror_msg_and_die("Cannot listen() on port %i", IDENT_PORT);
124 static void handlexitsigs(int signum)
126 if (unlink(PIDFILE) < 0)
127 close(open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0644));
131 /* May succeed. If not, won't care. */
132 static inline void writepid(uid_t nobody, uid_t nogrp)
135 int fd = open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0664);
140 snprintf(buf, 23, "%d\n", getpid());
141 write(fd, buf, strlen(buf));
142 fchown(fd, nobody, nogrp);
145 /* should this handle ILL, ... (see signal(7)) */
146 signal(SIGTERM, handlexitsigs);
147 signal(SIGINT, handlexitsigs);
148 signal(SIGQUIT, handlexitsigs);
151 /* return 0 as parent, 1 as child */
152 static int godaemon(void)
159 bb_perror_msg_and_die("Could not fork");
162 pw = getpwnam(nobodystr);
164 bb_error_msg_and_die("Cannot find uid/gid of user '%s'", nobodystr);
167 writepid(nobody, nogrp);
171 if (setgid(nogrp)) bb_error_msg_and_die("Could not setgid()");
172 if (setuid(nobody)) bb_error_msg_and_die("Could not setuid()");
176 signal(SIGHUP, SIG_IGN);
177 signal(SIGPIPE, SIG_IGN); /* connection closed when writing (raises ???) */
181 openlog(bb_applet_name, 0, LOG_DAEMON);
188 static void deleteConn(int s)
197 * Most of the time there is 0 connections. Most often that there
198 * is connections, there is just one connection. When this one connection
199 * closes, i == G.conncnt = 0 -> no copying.
200 * When there is more than one connection, the oldest connections closes
201 * earlier on average. When this happens, the code below starts copying
202 * the connection structure w/ highest index to the place which which is
203 * just deleted. This means that the connection structures are no longer
204 * in chronological order. I'd quess this means that when there is more
205 * than 1 connection, on average every other connection structure needs
206 * to be copied over the time all these connections are deleted.
208 if (i != G.conncnt) {
209 memcpy(&conns[i], &conns[G.conncnt], sizeof(conns[0]));
210 movefd(G.conncnt + FCS, s);
213 FD_CLR(G.conncnt + FCS, &G.readfds);
216 static int closeOldest(void)
218 time_t min = conns[0].lasttime;
222 for (i = 1; i < MAXCONNS; i++)
223 if (conns[i].lasttime < min)
226 replyError(idx + FCS, "X-SERVER-TOO-BUSY");
232 static int checkInput(char *buf, int len, int l)
235 for (i = len; i < len + l; ++i)
241 int fakeidentd_main(int argc, char **argv)
243 memset(conns, 0, sizeof(conns));
244 memset(&G, 0, sizeof(G));
246 FD_SET(0, &G.readfds);
248 /* handle -b <ip> parameter */
249 bb_getopt_ulflags(argc, argv, "b:", &bind_ip_address);
250 /* handle optional REPLY STRING */
252 G.identuser = argv[optind];
254 G.identuser = nobodystr;
256 /* daemonize and have the parent return */
260 /* main loop where we process all events and never exit */
262 fd_set rfds = G.readfds;
263 struct timeval tv = { 15, 0 };
265 int tim = time(NULL);
267 select(G.conncnt + FCS, &rfds, NULL, NULL, G.conncnt? &tv: NULL);
269 for (i = G.conncnt - 1; i >= 0; i--) {
272 if (FD_ISSET(s, &rfds)) {
273 char *buf = conns[i].buf;
274 unsigned int len = conns[i].len;
277 if ((l = read(s, buf + len, sizeof(conns[0].buf) - len)) > 0) {
278 if (checkInput(buf, len, l)) {
281 } else if (len + l >= sizeof(conns[0].buf)) {
282 replyError(s, "X-INVALID-REQUEST");
291 conns[i].lasttime = tim;
297 /* implement as time_after() in linux kernel sources ... */
298 if (conns[i].lasttime + MAXIDLETIME <= tim) {
299 replyError(s, "X-TIMEOUT");
305 if (FD_ISSET(0, &rfds)) {
306 int s = accept(0, NULL, 0);
309 if (errno != EINTR) /* EINTR */
310 syslog(LOG_ERR, "accept: %s", strerror(errno));
312 if (G.conncnt == MAXCONNS)
317 movefd(s, i + FCS); /* move if not already there */
318 FD_SET(i + FCS, &G.readfds);
321 conns[i].lasttime = time(NULL);
324 } /* end of while(1) */
329 static int parseAddrs(char *ptr, char **myaddr, char **heraddr);
330 static void reply(int s, char *buf)
332 char *myaddr, *heraddr;
334 myaddr = heraddr = NULL;
336 if (parseAddrs(buf, &myaddr, &heraddr))
337 replyError(s, "X-INVALID-REQUEST");
340 iv[0].iov_base = myaddr; iv[0].iov_len = strlen(myaddr);
341 iv[1].iov_base = ", "; iv[1].iov_len = 2;
342 iv[2].iov_base = heraddr; iv[2].iov_len = strlen(heraddr);
343 iv[3].iov_base = (void *)ident_substr; iv[3].iov_len = ident_substr_len;
344 iv[4].iov_base = (void *)G.identuser; iv[4].iov_len = strlen(G.identuser);
345 iv[5].iov_base = "\r\n"; iv[5].iov_len = 2;
350 static void replyError(int s, char *buf)
353 iv[0].iov_base = "0, 0 : ERROR : "; iv[0].iov_len = 15;
354 iv[1].iov_base = buf; iv[1].iov_len = strlen(buf);
355 iv[2].iov_base = "\r\n"; iv[2].iov_len = 2;
359 static int chmatch(char c, char *chars)
361 for (; *chars; chars++)
367 static int skipchars(char **p, char *chars)
369 while (chmatch(**p, chars))
371 if (**p == '\r' || **p == '\n')
376 static int parseAddrs(char *ptr, char **myaddr, char **heraddr)
378 /* parse <port-on-server> , <port-on-client> */
380 if (!skipchars(&ptr, " \t"))
385 if (!skipchars(&ptr, "1234567890"))
388 if (!chmatch(*ptr, " \t,"))
393 if (!skipchars(&ptr, " \t,") )
398 skipchars(&ptr, "1234567890");
400 if (!chmatch(*ptr, " \n\r"))