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.
18 #include <sys/syslog.h>
22 #include <sys/syslog.h>
24 #include <sys/socket.h>
29 #define IDENT_PORT 113
31 #define MAXIDLETIME 45
33 static const char ident_substr[] = " : USERID : UNIX : ";
34 enum { ident_substr_len = sizeof(ident_substr) - 1 };
35 #define PIDFILE "/var/run/identd.pid"
38 * We have to track the 'first connection socket' so that we
39 * don't go around closing file descriptors for non-clients.
41 * descriptor setup normally
43 * 1 = syslog fd (hopefully -- otherwise this won't work)
44 * 2 = connection socket after detached from tty. standard error before that
45 * 3 - 2 + MAXCONNS = rest connection sockets
47 * To try to make sure that syslog fd is what is "requested", the that fd
48 * is closed before openlog() call. It can only severely fail if fd 0
49 * is initially closed.
54 * FD of the connection is always the index of the connection structure
55 * in `conns' array + FCS
63 /* When using global variables, bind those at least to a structure. */
65 const char *identuser;
73 static void reply(int s, char *buf);
74 static void replyError(int s, char *buf);
76 static const char *nobodystr = "nobody"; /* this needs to be declared like this */
77 static char *bind_ip_address = "0.0.0.0";
79 static inline void movefd(int from, int to)
87 static void inetbind(void)
90 struct sockaddr_in addr;
91 int len = sizeof(addr);
95 if ((se = getservbyname("identd", "tcp")) == NULL)
100 s = bb_xsocket(AF_INET, SOCK_STREAM, 0);
102 setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
104 memset(&addr, 0, sizeof(addr));
105 addr.sin_addr.s_addr = inet_addr(bind_ip_address);
106 addr.sin_family = AF_INET;
107 addr.sin_port = htons(port);
109 bb_xbind(s, (struct sockaddr *)&addr, len);
115 static void handlexitsigs(int signum)
117 if (unlink(PIDFILE) < 0)
118 close(open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0644));
122 /* May succeed. If not, won't care. */
123 static inline void writepid(uid_t nobody, uid_t nogrp)
126 int fd = open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0664);
131 snprintf(buf, 23, "%d\n", getpid());
132 write(fd, buf, strlen(buf));
133 fchown(fd, nobody, nogrp);
136 /* should this handle ILL, ... (see signal(7)) */
137 signal(SIGTERM, handlexitsigs);
138 signal(SIGINT, handlexitsigs);
139 signal(SIGQUIT, handlexitsigs);
142 /* return 0 as parent, 1 as child */
143 static int godaemon(void)
150 bb_perror_msg_and_die("Could not fork");
153 pw = getpwnam(nobodystr);
155 bb_error_msg_and_die("Cannot find uid/gid of user '%s'", nobodystr);
158 writepid(nobody, nogrp);
162 if (setgid(nogrp)) bb_error_msg_and_die("Could not setgid()");
163 if (setuid(nobody)) bb_error_msg_and_die("Could not setuid()");
167 signal(SIGHUP, SIG_IGN);
168 signal(SIGPIPE, SIG_IGN); /* connection closed when writing (raises ???) */
172 openlog(bb_applet_name, 0, LOG_DAEMON);
179 static void deleteConn(int s)
188 * Most of the time there is 0 connections. Most often that there
189 * is connections, there is just one connection. When this one connection
190 * closes, i == G.conncnt = 0 -> no copying.
191 * When there is more than one connection, the oldest connections closes
192 * earlier on average. When this happens, the code below starts copying
193 * the connection structure w/ highest index to the place which which is
194 * just deleted. This means that the connection structures are no longer
195 * in chronological order. I'd quess this means that when there is more
196 * than 1 connection, on average every other connection structure needs
197 * to be copied over the time all these connections are deleted.
199 if (i != G.conncnt) {
200 memcpy(&conns[i], &conns[G.conncnt], sizeof(conns[0]));
201 movefd(G.conncnt + FCS, s);
204 FD_CLR(G.conncnt + FCS, &G.readfds);
207 static int closeOldest(void)
209 time_t min = conns[0].lasttime;
213 for (i = 1; i < MAXCONNS; i++)
214 if (conns[i].lasttime < min)
217 replyError(idx + FCS, "X-SERVER-TOO-BUSY");
223 static int checkInput(char *buf, int len, int l)
226 for (i = len; i < len + l; ++i)
232 int fakeidentd_main(int argc, char **argv)
234 memset(conns, 0, sizeof(conns));
235 memset(&G, 0, sizeof(G));
237 FD_SET(0, &G.readfds);
239 /* handle -b <ip> parameter */
240 bb_getopt_ulflags(argc, argv, "b:", &bind_ip_address);
241 /* handle optional REPLY STRING */
243 G.identuser = argv[optind];
245 G.identuser = nobodystr;
247 /* daemonize and have the parent return */
251 /* main loop where we process all events and never exit */
253 fd_set rfds = G.readfds;
254 struct timeval tv = { 15, 0 };
256 int tim = time(NULL);
258 select(G.conncnt + FCS, &rfds, NULL, NULL, G.conncnt? &tv: NULL);
260 for (i = G.conncnt - 1; i >= 0; i--) {
263 if (FD_ISSET(s, &rfds)) {
264 char *buf = conns[i].buf;
265 unsigned int len = conns[i].len;
268 if ((l = read(s, buf + len, sizeof(conns[0].buf) - len)) > 0) {
269 if (checkInput(buf, len, l)) {
272 } else if (len + l >= sizeof(conns[0].buf)) {
273 replyError(s, "X-INVALID-REQUEST");
282 conns[i].lasttime = tim;
288 /* implement as time_after() in linux kernel sources ... */
289 if (conns[i].lasttime + MAXIDLETIME <= tim) {
290 replyError(s, "X-TIMEOUT");
296 if (FD_ISSET(0, &rfds)) {
297 int s = accept(0, NULL, 0);
300 if (errno != EINTR) /* EINTR */
301 syslog(LOG_ERR, "accept: %s", strerror(errno));
303 if (G.conncnt == MAXCONNS)
308 movefd(s, i + FCS); /* move if not already there */
309 FD_SET(i + FCS, &G.readfds);
312 conns[i].lasttime = time(NULL);
315 } /* end of while(1) */
320 static int parseAddrs(char *ptr, char **myaddr, char **heraddr);
321 static void reply(int s, char *buf)
323 char *myaddr, *heraddr;
325 myaddr = heraddr = NULL;
327 if (parseAddrs(buf, &myaddr, &heraddr))
328 replyError(s, "X-INVALID-REQUEST");
331 iv[0].iov_base = myaddr; iv[0].iov_len = strlen(myaddr);
332 iv[1].iov_base = ", "; iv[1].iov_len = 2;
333 iv[2].iov_base = heraddr; iv[2].iov_len = strlen(heraddr);
334 iv[3].iov_base = (void *)ident_substr; iv[3].iov_len = ident_substr_len;
335 iv[4].iov_base = (void *)G.identuser; iv[4].iov_len = strlen(G.identuser);
336 iv[5].iov_base = "\r\n"; iv[5].iov_len = 2;
341 static void replyError(int s, char *buf)
344 iv[0].iov_base = "0, 0 : ERROR : "; iv[0].iov_len = 15;
345 iv[1].iov_base = buf; iv[1].iov_len = strlen(buf);
346 iv[2].iov_base = "\r\n"; iv[2].iov_len = 2;
350 static int chmatch(char c, char *chars)
352 for (; *chars; chars++)
358 static int skipchars(char **p, char *chars)
360 while (chmatch(**p, chars))
362 if (**p == '\r' || **p == '\n')
367 static int parseAddrs(char *ptr, char **myaddr, char **heraddr)
369 /* parse <port-on-server> , <port-on-client> */
371 if (!skipchars(&ptr, " \t"))
376 if (!skipchars(&ptr, "1234567890"))
379 if (!chmatch(*ptr, " \t,"))
384 if (!skipchars(&ptr, " \t,") )
389 skipchars(&ptr, "1234567890");
391 if (!chmatch(*ptr, " \n\r"))