5 * (c) 2012 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Yet Another Ident Daemon (YAID).
12 * YAID is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * YAID is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with YAID; if not, write to the Free Software Foundation,
24 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 /*----- Header files ------------------------------------------------------*/
31 /*----- Data structures ---------------------------------------------------*/
33 /* A write buffer is the gadget which keeps track of our output and writes
34 * portions of it out as and when connections are ready for it.
38 size_t o; /* Offset of remaining data */
39 size_t n; /* Length of remaining data */
40 sel_file wr; /* Write selector */
41 void (*func)(int /*err*/, void *); /* Function to call on completion */
42 void *p; /* Context for `func' */
43 unsigned char buf[WRBUFSZ]; /* Output buffer */
46 /* Structure for a listening socket. There's one of these for each address
47 * family we're looking after.
50 const struct addrops *ao; /* Address family operations */
51 sel_file f; /* Watch for incoming connections */
54 /* The main structure for a client. */
56 int fd; /* The connection to the client */
57 selbuf b; /* Accumulate lines of input */
58 union addr raddr; /* Remote address */
59 struct query q; /* The clients query and our reply */
60 struct sel_timer t; /* Timeout for idle or doomed conn */
61 struct listen *l; /* Back to the listener (and ops) */
62 struct writebuf wb; /* Write buffer for our reply */
63 struct proxy *px; /* Proxy if conn goes via NAT */
64 struct client *next; /* Next in a chain of clients */
67 /* A proxy connection. */
69 int fd; /* Connection; -1 if in progress */
70 struct client *c; /* Back to the client */
71 conn cn; /* Nonblocking connection */
72 selbuf b; /* Accumulate the response line */
73 struct writebuf wb; /* Write buffer for query */
74 char nat[ADDRLEN]; /* Server address, as text */
75 struct proxy *next; /* Next in a chain of proxies */
78 /*----- Static variables --------------------------------------------------*/
80 static sel_state sel; /* I/O multiplexer state */
82 static const char *pidfile = 0; /* Where to write daemon's pid */
84 static const char *policyfile = POLICYFILE; /* Filename for global policy */
85 static const struct policy default_policy = POLICY_INIT(A_NAME);
86 static policy_v policy = DA_INIT; /* Vector of global policy rules */
87 static fwatch polfw; /* Watch policy file for changes */
89 static unsigned char tokenbuf[4096]; /* Random-ish data for tokens */
90 static size_t tokenptr = sizeof(tokenbuf); /* Current read position */
92 static struct client *dead_clients = 0; /* List of defunct clients */
93 static struct proxy *dead_proxies = 0; /* List of defunct proxies */
95 static unsigned flags = 0; /* Various interesting flags */
96 #define F_SYSLOG 1u /* Use syslog for logging */
97 #define F_RUNNING 2u /* Running properly now */
99 /*----- Ident protocol parsing --------------------------------------------*/
101 /* Advance *PP over whitespace characters. */
102 static void skipws(const char **pp)
103 { while (isspace((unsigned char )**pp)) (*pp)++; }
105 /* Copy a token of no more than N bytes starting at *PP into Q, advancing *PP
108 static int idtoken(const char **pp, char *q, size_t n)
115 if (*p == ':' || *p <= 32 || *p >= 127) break;
125 /* Read an unsigned decimal number from *PP, and store it in *II. Check that
126 * it's between MIN and MAX, and advance *PP over it. Return zero for
127 * success, or nonzero if something goes wrong.
129 static int unum(const char **pp, unsigned *ii, unsigned min, unsigned max)
136 if (!isdigit((unsigned char)**pp)) return (-1);
137 e = errno; errno = 0;
138 i = strtoul(*pp, &q, 10);
139 if (errno) return (-1);
142 if (i < min || i > max) return (-1);
147 /*----- Asynchronous writing ----------------------------------------------*/
149 /* Callback for actually writing stuff from a `writebuf'. */
150 static void write_out(int fd, unsigned mode, void *p)
153 struct writebuf *wb = p;
155 /* Try to write something. */
156 if ((n = write(fd, wb->buf + wb->o, wb->n)) < 0) {
157 if (errno == EAGAIN || errno == EWOULDBLOCK) return;
160 wb->func(errno, wb->p);
165 /* If there's nothing left then restore the buffer to its empty state. */
173 /* Queue N bytes starting at P to be written. */
174 static int queue_write(struct writebuf *wb, const void *p, size_t n)
176 /* Maybe there's nothing to actually do. */
179 /* Make sure it'll fit. */
180 if (wb->n - wb->o + n > WRBUFSZ) return (-1);
182 /* If there's anything there already, then make sure it's at the start of
183 * the available space.
186 memmove(wb->buf, wb->buf + wb->o, wb->n);
190 /* If there's nothing currently there, then we're not requesting write
191 * notifications, so set that up, and force an initial wake-up.
194 sel_addfile(&wb->wr);
198 /* Copy the new material over. */
199 memcpy(wb->buf + wb->n, p, n);
206 /* Release resources allocated to WB. */
207 static void free_writebuf(struct writebuf *wb)
208 { if (wb->n) sel_rmfile(&wb->wr); }
210 /* Initialize a writebuf in *WB, writing to file descriptor FD. On
211 * completion, call FUNC, passing it P and an error indicator: either 0 for
212 * success or an `errno' value on failure.
214 static void init_writebuf(struct writebuf *wb,
215 int fd, void (*func)(int, void *), void *p)
217 sel_initfile(&sel, &wb->wr, fd, SEL_WRITE, write_out, wb);
223 /*----- General utilities -------------------------------------------------*/
225 static void vlogmsg(const struct query *q, int prio,
226 const char *msg, va_list *ap)
234 dputsock(&d, q->ao, &q->s[L]);
235 dstr_puts(&d, " <-> ");
236 dputsock(&d, q->ao, &q->s[R]);
239 dstr_vputf(&d, msg, ap);
241 if (!(flags & F_RUNNING))
243 else if (flags & F_SYSLOG)
244 syslog(prio, "%s", d.buf);
248 strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S %z", tm);
249 fprintf(stderr, "%s %s: %s\n", buf, QUIS, d.buf);
255 /* Format and log MSG somewhere sensible, at the syslog(3) priority PRIO.
256 * Prefix it with a description of the query Q, if non-null.
258 void logmsg(const struct query *q, int prio, const char *msg, ...)
263 vlogmsg(q, prio, msg, &ap);
267 /* Fix up a socket FD so that it won't bite us. Returns zero on success, or
270 static int fix_up_socket(int fd, const char *what)
274 if (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0)) {
275 logmsg(0, LOG_ERR, "failed to set %s connection nonblocking: %s",
276 what, strerror(errno));
280 if (setsockopt(fd, SOL_SOCKET, SO_OOBINLINE, &yes, sizeof(yes))) {
282 "failed to disable `out-of-band' data on %s connection: %s",
283 what, strerror(errno));
290 /*----- Client output functions -------------------------------------------*/
292 static void disconnect_client(struct client *c);
294 /* Notification that output has been written. If successful, re-enable the
295 * input buffer and prepare for another query.
297 static void done_client_write(int err, void *p)
299 struct client *c = p;
302 selbuf_enable(&c->b);
304 logmsg(&c->q, LOG_ERR, "failed to send reply: %s", strerror(err));
305 disconnect_client(c);
309 /* Format the message FMT and queue it to be sent to the client. Client
310 * input will be disabled until the write completes.
312 static void PRINTF_LIKE(2, 3)
313 write_to_client(struct client *c, const char *fmt, ...)
320 n = vsnprintf(buf, sizeof(buf), fmt, ap);
322 logmsg(&c->q, LOG_ERR, "failed to format output: %s", strerror(errno));
323 disconnect_client(c);
325 } else if (n > sizeof(buf)) {
326 logmsg(&c->q, LOG_ERR, "output too long for client send buffer");
327 disconnect_client(c);
331 selbuf_disable(&c->b);
332 if (queue_write(&c->wb, buf, n)) {
333 logmsg(&c->q, LOG_ERR, "write buffer overflow");
334 disconnect_client(c);
338 /* Format a reply to the client, with the form LPORT:RPORT:TY:TOK0[:TOK1].
339 * Typically, TY will be `ERROR' or `USERID'. In the former case, TOK0 will
340 * be the error token and TOK1 will be null; in the latter case, TOK0 will be
341 * the operating system and TOK1 the user name.
343 static void reply(struct client *c, const char *ty,
344 const char *tok0, const char *tok1)
346 write_to_client(c, "%u,%u:%s:%s%s%s\r\n",
347 c->q.s[L].port, c->q.s[R].port, ty,
348 tok0, tok1 ? ":" : "", tok1 ? tok1 : "");
351 /* Mapping from error codes to their protocol tokens. */
352 const char *const errtok[] = {
353 #define DEFTOK(err, tok) tok,
358 /* Report an error with code ERR to the client. */
359 static void reply_error(struct client *c, unsigned err)
361 assert(err < E_LIMIT);
362 reply(c, "ERROR", errtok[err], 0);
365 /*----- NAT proxy functions -----------------------------------------------*/
367 /* Cancel the proxy operation PX, closing the connection and releasing
368 * resources. This is used for both normal and unexpected closures.
370 static void cancel_proxy(struct proxy *px)
376 selbuf_disable(&px->b);
379 selbuf_enable(&px->c->b);
380 px->next = dead_proxies;
384 /* Delayed destruction of unsafe parts of proxies. */
385 static void reap_dead_proxies(void)
387 struct proxy *px, *pp;
389 for (px = dead_proxies; px; px = pp) {
392 selbuf_destroy(&px->b);
393 free_writebuf(&px->wb);
400 /* Notification that a line (presumably a reply) has been received from the
401 * server. We should check it, log it, and propagate the answer back.
402 * Whatever happens, this proxy operation is now complete.
404 static void proxy_line(char *line, size_t sz, void *p)
406 struct proxy *px = p;
408 const char *q = line;
411 /* Trim trailing space. */
412 while (sz && isspace((unsigned char)line[sz - 1])) sz--;
414 /* Parse the port numbers. These should match the request. */
415 if (unum(&q, &lp, 1, 65535)) goto syntax;
416 skipws(&q); if (*q != ',') goto syntax; q++;
417 if (unum(&q, &rp, 1, 65535)) goto syntax;
418 skipws(&q); if (*q != ':') goto syntax; q++;
419 if (lp != px->c->q.u.nat.port || rp != px->c->q.s[R].port) goto syntax;
421 /* Find out what kind of reply this is. */
422 if (idtoken(&q, buf, sizeof(buf))) goto syntax;
423 skipws(&q); if (*q != ':') goto syntax; q++;
425 if (strcmp(buf, "ERROR") == 0) {
427 /* Report the error without interpreting it. It might be meaningful to
431 logmsg(&px->c->q, LOG_ERR, "proxy error from %s: %s", px->nat, q);
432 reply(px->c, "ERROR", q, 0);
434 } else if (strcmp(buf, "USERID") == 0) {
436 /* Parse out the operating system and user name, and pass them on. */
437 if (idtoken(&q, buf, sizeof(buf))) goto syntax;
438 skipws(&q); if (*q != ':') goto syntax; q++;
440 logmsg(&px->c->q, LOG_ERR, "user `%s'; proxy = %s, os = %s",
442 reply(px->c, "USERID", buf, q);
449 /* We didn't understand the message from the client. */
450 logmsg(&px->c->q, LOG_ERR, "failed to parse response from %s", px->nat);
451 reply_error(px->c, E_UNKNOWN);
453 /* All finished, no matter what. */
457 /* Notification that we have written the query to the server. Await a
458 * response if successful.
460 static void done_proxy_write(int err, void *p)
462 struct proxy *px = p;
465 logmsg(&px->c->q, LOG_ERR, "failed to proxy query to %s: %s",
466 px->nat, strerror(errno));
467 reply_error(px->c, E_UNKNOWN);
471 selbuf_enable(&px->b);
474 /* Notification that the connection to the server is either established or
475 * failed. In the former case, queue the right query.
477 static void proxy_connected(int fd, void *p)
479 struct proxy *px = p;
483 /* If the connection failed then report the problem and give up. */
485 logmsg(&px->c->q, LOG_ERR,
486 "failed to make %s proxy connection to %s: %s",
487 px->c->l->ao->name, px->nat, strerror(errno));
488 reply_error(px->c, E_UNKNOWN);
493 /* We're now ready to go, so set things up. */
495 selbuf_init(&px->b, &sel, fd, proxy_line, px);
496 selbuf_setsize(&px->b, 1024);
497 selbuf_disable(&px->b);
498 init_writebuf(&px->wb, fd, done_proxy_write, px);
500 /* Write the query. This buffer is large enough because we've already
501 * range-checked the remote the port number and the local one came from the
502 * kernel, which we trust not to do anything stupid.
504 n = sprintf(buf, "%u,%u\r\n", px->c->q.u.nat.port, px->c->q.s[R].port);
505 queue_write(&px->wb, buf, n);
508 /* Proxy the query through to a client machine for which we're providing NAT
511 static void proxy_query(struct client *c)
514 struct sockaddr_storage ss;
519 /* Allocate the context structure for the NAT. */
520 px = xmalloc(sizeof(*px));
522 /* We'll use the client host's address in lots of log messages, so we may
523 * as well format it once and use it over and over.
525 inet_ntop(c->q.ao->af, &c->q.u.nat.addr, px->nat, sizeof(px->nat));
527 /* Create the socket for the connection. */
528 if ((fd = socket(c->q.ao->af, SOCK_STREAM, 0)) < 0) {
529 logmsg(&c->q, LOG_ERR, "failed to make %s socket for proxy: %s",
530 c->l->ao->name, strerror(errno));
533 if (fix_up_socket(fd, "proxy")) goto err_1;
535 /* Set up the connection to the client host. The connection interface is a
536 * bit broken: if the connection completes immediately, then the callback
537 * function is called synchronously, and that might decide to shut
538 * everything down. So we must have fully initialized our context before
539 * calling `conn_init', and mustn't touch it again afterwards -- since the
540 * block may have been freed.
544 c->l->ao->socket_to_sockaddr(&s, &ss, &ssz);
545 selbuf_disable(&c->b);
546 c->px = px; px->c = c;
548 if (conn_init(&px->cn, &sel, fd, (struct sockaddr *)&ss, ssz,
549 proxy_connected, px)) {
550 logmsg(&c->q, LOG_ERR, "failed to make %s proxy connection to %s: %s",
551 c->l->ao->name, px->nat, strerror(errno));
555 /* All ready to go. */
558 /* Tidy up after various kinds of failures. */
560 selbuf_enable(&c->b);
565 reply_error(c, E_UNKNOWN);
568 /*----- Client connection functions ---------------------------------------*/
570 /* Disconnect a client, freeing up any associated resources. */
571 static void disconnect_client(struct client *c)
573 selbuf_disable(&c->b);
576 free_writebuf(&c->wb);
577 if (c->px) cancel_proxy(c->px);
578 c->next = dead_clients;
582 /* Throw away dead clients now that we've reached a safe point in the
585 static void reap_dead_clients(void)
587 struct client *c, *cc;
588 for (c = dead_clients; c; c = cc) {
590 selbuf_destroy(&c->b);
596 /* Time out a client because it's been idle for too long. */
597 static void timeout_client(struct timeval *tv, void *p)
599 struct client *c = p;
600 logmsg(&c->q, LOG_NOTICE, "timing out idle or stuck client");
601 sel_addtimer(&sel, &c->t, tv, timeout_client, 0);
602 disconnect_client(c);
605 /* Reset the client idle timer, as a result of activity. Set EXISTP if
606 * there is an existing timer which needs to be removed.
608 static void reset_client_timer(struct client *c, int existp)
612 gettimeofday(&tv, 0);
614 if (existp) sel_rmtimer(&c->t);
615 sel_addtimer(&sel, &c->t, &tv, timeout_client, c);
618 /* Write a pseudorandom token into the buffer at P, which must have space for
619 * at least TOKENSZ bytes.
621 #define TOKENRANDSZ 8
622 #define TOKENSZ ((4*TOKENRANDSZ + 5)/3)
623 static void user_token(char *p)
628 static const char tokmap[64] =
629 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.-";
631 /* If there's not enough pseudorandom stuff lying around, then read more
634 if (tokenptr + TOKENRANDSZ >= sizeof(tokenbuf)) {
635 fill_random(tokenbuf, sizeof(tokenbuf));
639 /* Now encode the bytes using a slightly tweaked base-64 encoding. Read
640 * bytes into the accumulator and write out characters while there's
643 for (i = 0; i < TOKENRANDSZ; i++) {
644 a = (a << 8) | tokenbuf[tokenptr++]; b += 8;
647 *p++ = tokmap[(a >> b) & 0x3f];
651 /* If there's anything left in the accumulator then flush it out. */
653 *p++ = tokmap[(a << (6 - b)) & 0x3f];
655 /* Null-terminate the token. */
659 /* Notification that a line has been received from the client. Parse it,
660 * find out about the connection it's referring to, apply the relevant
661 * policy rules, and produce a response. This is where almost everything
662 * interesting happens.
664 static void client_line(char *line, size_t len, void *p)
666 struct client *c = p;
668 struct passwd *pw = 0;
669 const struct policy *pol;
671 struct policy upol = POLICY_INIT(A_LIMIT);
672 struct policy_file pf;
676 /* If the connection has closed, then tidy stuff away. */
677 c->q.s[R].addr = c->raddr;
678 c->q.s[L].port = c->q.s[R].port = 0;
680 disconnect_client(c);
684 /* Client activity, so update the timer. */
685 reset_client_timer(c, 1);
687 /* See if the policy file has changed since we last looked. If so, try to
688 * read the new version.
690 if (fwatch_update(&polfw, policyfile)) {
691 logmsg(0, LOG_INFO, "reload master policy file `%s'", policyfile);
692 load_policy_file(policyfile, &policy);
695 /* Read the local and remote port numbers into the query structure. */
697 if (unum(&q, &c->q.s[L].port, 1, 65535)) goto bad;
698 skipws(&q); if (*q != ',') goto bad; q++;
699 if (unum(&q, &c->q.s[R].port, 1, 65535)) goto bad;
700 skipws(&q); if (*q) goto bad;
702 /* Identify the connection. Act on the result. */
707 /* We found a user. Track down the user's password entry, because
708 * we'll want that later. Most of the processing for this case is
711 if ((pw = getpwuid(c->q.u.uid)) == 0) {
712 logmsg(&c->q, LOG_ERR, "no passwd entry for user %d", c->q.u.uid);
713 reply_error(c, E_NOUSER);
719 /* We've acted as a NAT for this connection. Proxy the query through
720 * to the actal client host.
726 /* We failed to identify the connection for some reason. We should
727 * already have logged an error, so there's not much to do here.
729 reply_error(c, c->q.u.error);
733 /* Something happened that we don't understand. */
737 /* Search the table of policy rules to find a match. */
738 for (i = 0; i < DA_LEN(&policy); i++) {
739 pol = &DA(&policy)[i];
740 if (!match_policy(pol, &c->q)) continue;
742 /* If this is something simple, then apply the resulting policy rule. */
743 if (pol->act.act != A_USER) goto match;
745 /* The global policy has decided to let the user have a say, so we must
746 * parse the user file.
749 dstr_putf(&d, "%s/.yaid.policy", pw->pw_dir);
750 if (open_policy_file(&pf, d.buf, "user policy file", &c->q, OPF_NOENTOK))
752 while ((t = read_policy_file(&pf)) < T_ERROR) {
754 /* Give up after 100 lines or if there's an error. If the user's
755 * policy is that complicated, something's gone very wrong. Or there's
756 * too much commentary or something.
759 logmsg(&c->q, LOG_ERR, "%s:%d: user policy file too long",
764 /* If this was a blank line, just go around again. */
765 if (t != T_OK) continue;
767 /* If this isn't a match, go around for the next rule. */
768 if (!match_policy(&pf.p, &c->q)) continue;
770 /* Check that the user is allowed to request this action. If not, see
771 * if there's a more acceptable action later on.
773 if (!(pol->act.u.user & (1 << pf.p.act.act))) {
774 logmsg(&c->q, LOG_ERR,
775 "%s:%d: user action forbidden by global policy",
780 /* We've found a match, so grab it, close the file, and say we're
783 upol = pf.p; pol = &upol;
785 close_policy_file(&pf);
789 close_policy_file(&pf);
793 /* No match: apply the built-in default policy. */
794 pol = &default_policy;
797 switch (pol->act.act) {
800 /* Report the actual user's name. */
801 logmsg(&c->q, LOG_INFO, "user `%s' (%d)", pw->pw_name, c->q.u.uid);
802 reply(c, "USERID", "UNIX", pw->pw_name);
806 /* Report an arbitrary token which we can look up in our log file. */
808 logmsg(&c->q, LOG_INFO, "user `%s' (%d); token = %s",
809 pw->pw_name, c->q.u.uid, buf);
810 reply(c, "USERID", "OTHER", buf);
814 /* Deny that there's anyone there at all. */
815 logmsg(&c->q, LOG_INFO, "user `%s' (%d); denying",
816 pw->pw_name, c->q.u.uid);
820 /* Report the user as being hidden. */
821 logmsg(&c->q, LOG_INFO, "user `%s' (%d); hiding",
822 pw->pw_name, c->q.u.uid);
823 reply_error(c, E_HIDDEN);
827 /* Tell an egregious lie about who the user is. */
828 logmsg(&c->q, LOG_INFO, "user `%s' (%d); lie = `%s'",
829 pw->pw_name, c->q.u.uid, pol->act.u.lie);
830 reply(c, "USERID", "UNIX", pol->act.u.lie);
834 /* Something has gone very wrong. */
843 logmsg(&c->q, LOG_ERR, "failed to parse query from client");
844 disconnect_client(c);
847 /* Notification that a new client has connected. Prepare to read a query. */
848 static void accept_client(int fd, unsigned mode, void *p)
850 struct listen *l = p;
852 struct sockaddr_storage ssr, ssl;
853 size_t ssz = sizeof(ssr);
856 /* Accept the new connection. */
857 if ((sk = accept(fd, (struct sockaddr *)&ssr, &ssz)) < 0) {
858 if (errno != EAGAIN && errno == EWOULDBLOCK) {
859 logmsg(0, LOG_ERR, "failed to accept incoming %s connection: %s",
860 l->ao->name, strerror(errno));
864 if (fix_up_socket(sk, "incoming client")) { close(sk); return; }
866 /* Build a client block and fill it in. */
867 c = xmalloc(sizeof(*c));
871 /* Collect the local and remote addresses. */
872 l->ao->sockaddr_to_addr(&ssr, &c->raddr);
874 if (getsockname(sk, (struct sockaddr *)&ssl, &ssz)) {
876 "failed to read local address for incoming %s connection: %s",
877 l->ao->name, strerror(errno));
882 l->ao->sockaddr_to_addr(&ssl, &c->q.s[L].addr);
883 c->q.s[L].port = c->q.s[R].port = 0;
885 /* Set stuff up for reading the query and sending responses. */
886 selbuf_init(&c->b, &sel, sk, client_line, c);
887 selbuf_setsize(&c->b, 1024);
888 reset_client_timer(c, 0);
891 init_writebuf(&c->wb, sk, done_client_write, c);
894 /*----- Main code ---------------------------------------------------------*/
896 /* Set up a listening socket for the address family described by AO,
899 static int make_listening_socket(const struct addrops *ao, int port)
904 struct sockaddr_storage ss;
908 /* Make the socket. */
909 if ((fd = socket(ao->af, SOCK_STREAM, 0)) < 0) {
910 if (errno == EAFNOSUPPORT) return (-1);
911 die(1, "failed to create %s listening socket: %s",
912 ao->name, strerror(errno));
915 /* Build the appropriate local address. */
918 ao->socket_to_sockaddr(&s, &ss, &ssz);
920 /* Perform any initialization specific to the address type. */
921 if (ao->init_listen_socket(fd)) {
922 die(1, "failed to initialize %s listening socket: %s",
923 ao->name, strerror(errno));
926 /* Bind to the address. */
927 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
928 if (bind(fd, (struct sockaddr *)&ss, ssz)) {
929 die(1, "failed to bind %s listening socket: %s",
930 ao->name, strerror(errno));
933 /* Avoid unpleasant race conditions. */
934 if (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0)) {
935 die(1, "failed to set %s listening socket nonblocking: %s",
936 ao->name, strerror(errno));
939 /* Prepare to listen. */
941 die(1, "failed to listen for %s: %s", ao->name, strerror(errno));
943 /* Make a record of all of this. */
944 l = xmalloc(sizeof(*l));
946 sel_initfile(&sel, &l->f, fd, SEL_READ, accept_client, l);
953 /* Quit because of a fatal signal. */
954 static void NORETURN quit(int sig, void *p)
956 const char *signame = p;
958 logmsg(0, LOG_NOTICE, "shutting down on %s", signame);
959 if (pidfile) unlink(pidfile);
963 /* Answer whether the string pointed to by P consists entirely of digits. */
964 static int numericp(const char *p)
967 if (!isdigit((unsigned char)*p++)) return (0);
971 static void usage(FILE *fp)
973 pquis(fp, "Usage: $ [-Dl] [-G GROUP] [-U USER] [-P FILE] "
974 "[-c FILE] [-p PORT]\n");
977 static void version(FILE *fp)
978 { pquis(fp, "$, version " VERSION "\n"); }
980 static void help(FILE *fp)
982 version(fp); fputc('\n', fp);
985 Yet Another Ident Daemon. Really, the world doesn't need such a thing.\n\
986 It's just a shame none of the others do the right things.\n\
990 -h, --help Show this help message.\n\
991 -v, --version Show the version number.\n\
992 -u, --usage Show a very short usage summary.\n\
994 -D, --daemon Become a daemon, running in the background.\n\
995 -G, --group=GROUP Set group after initialization.\n\
996 -P, --pidfile=FILE Write process id to FILE.\n\
997 -U, --user=USER Set user after initialization.\n\
998 -c, --config=FILE Read global policy from FILE.\n\
999 -l, --syslog Write log messages using syslog(3).\n\
1000 -p, --port=PORT Listen for connections on this port.\n",
1004 int main(int argc, char *argv[])
1009 struct passwd *pw = 0;
1012 sig sigint, sigterm;
1018 const struct addrops *ao;
1023 /* Parse command-line options. */
1025 const struct option opts[] = {
1026 { "help", 0, 0, 'h' },
1027 { "version", 0, 0, 'v' },
1028 { "usage", 0, 0, 'u' },
1029 { "daemon", 0, 0, 'D' },
1030 { "group", OPTF_ARGREQ, 0, 'G' },
1031 { "pidfile", OPTF_ARGREQ, 0, 'P' },
1032 { "user", OPTF_ARGREQ, 0, 'U' },
1033 { "config", OPTF_ARGREQ, 0, 'c' },
1034 { "syslog", 0, 0, 'l' },
1035 { "port", OPTF_ARGREQ, 0, 'p' },
1039 if ((i = mdwopt(argc, argv, "hvuDG:P:U:c:lp:", opts, 0, 0, 0)) < 0)
1042 case 'h': help(stdout); exit(0);
1043 case 'v': version(stdout); exit(0);
1044 case 'u': usage(stdout); exit(0);
1045 case 'D': f |= f_daemon; break;
1046 case 'P': pidfile = optarg; break;
1047 case 'c': policyfile = optarg; break;
1048 case 'l': flags |= F_SYSLOG; break;
1050 if (numericp(optarg))
1052 else if ((gr = getgrnam(optarg)) == 0)
1053 die(1, "unknown group `%s'", optarg);
1058 if (numericp(optarg))
1060 else if ((pw = getpwnam(optarg)) == 0)
1061 die(1, "unknown user `%s'", optarg);
1066 if (numericp(optarg))
1067 port = atoi(optarg);
1068 else if ((s = getservbyname(optarg, "tcp")) == 0)
1069 die(1, "unknown service name `%s'", optarg);
1071 port = ntohs(s->s_port);
1073 default: f |= f_bogus; break;
1076 if (optind < argc) f |= f_bogus;
1077 if (f & f_bogus) { usage(stderr); exit(1); }
1079 /* If a user has been requested, but no group, then find the user's primary
1080 * group. If the user was given by name, then we already have a password
1081 * entry and should use that, in case two differently-named users have the
1082 * same uid but distinct gids.
1084 if (u != -1 && g == -1) {
1085 if (!pw && (pw = getpwuid(u)) == 0) {
1086 die(1, "failed to find password entry for user %d: "
1087 "request group explicitly", u);
1092 /* Initialize system-specific machinery. */
1095 /* Load the global policy rules. */
1096 fwatch_init(&polfw, policyfile);
1097 if (load_policy_file(policyfile, &policy))
1100 /* Set up the I/O event system. */
1103 /* Watch for some interesting signals. */
1105 sig_add(&sigint, SIGINT, quit, "SIGINT");
1106 sig_add(&sigterm, SIGTERM, quit, "SIGTERM");
1108 /* Listen for incoming connections. */
1109 for (ao = addroptab; ao->name; ao++)
1110 if (!make_listening_socket(ao, port)) any = 1;
1111 if (!any) die(1, "no IP protocols supported");
1113 /* Open the pidfile now, in case it's somewhere we can't write. */
1114 if (pidfile && (fp = fopen(pidfile, "w")) == 0) {
1115 die(1, "failed to open pidfile `%s' for writing: %s",
1116 pidfile, strerror(errno));
1119 /* If we're meant to use syslog, then open the log. */
1120 if (flags & F_SYSLOG)
1121 openlog(QUIS, 0, LOG_DAEMON);
1123 /* Drop privileges. */
1124 if ((g != -1 && (setegid(g) || setgid(g) ||
1125 (getuid() == 0 && setgroups(1, &g)))) ||
1126 (u != -1 && setuid(u)))
1127 die(1, "failed to drop privileges: %s", strerror(errno));
1129 /* Become a background process, if requested. */
1130 if ((f & f_daemon) && daemonize())
1131 die(1, "failed to become daemon: %s", strerror(errno));
1133 /* Write the process id to the pidfile. */
1135 fprintf(fp, "%d\n", getpid());
1139 /* And now we're going. */
1142 /* Read events and process them. */
1144 if (sel_select(&sel) && errno != EINTR)
1145 die(1, "select failed: %s", strerror(errno));
1146 reap_dead_proxies();
1147 reap_dead_clients();
1150 /* This just keeps the compiler happy. */
1154 /*----- That's all, folks -------------------------------------------------*/