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 /* Format and log MSG somewhere sensible, at the syslog(3) priority PRIO.
226 * Prefix it with a description of the query Q, if non-null.
228 void logmsg(const struct query *q, int prio, const char *msg, ...)
238 dputsock(&d, q->ao, &q->s[L]);
239 dstr_puts(&d, " <-> ");
240 dputsock(&d, q->ao, &q->s[R]);
243 dstr_vputf(&d, msg, &ap);
246 if (!(flags & F_RUNNING))
248 else if (flags & F_SYSLOG)
249 syslog(prio, "%s", d.buf);
253 strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S %z", tm);
254 fprintf(stderr, "%s %s: %s\n", buf, QUIS, d.buf);
260 /* Fix up a socket FD so that it won't bite us. Returns zero on success, or
263 static int fix_up_socket(int fd, const char *what)
267 if (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0)) {
268 logmsg(0, LOG_ERR, "failed to set %s connection nonblocking: %s",
269 what, strerror(errno));
273 if (setsockopt(fd, SOL_SOCKET, SO_OOBINLINE, &yes, sizeof(yes))) {
275 "failed to disable `out-of-band' data on %s connection: %s",
276 what, strerror(errno));
283 /*----- Client output functions -------------------------------------------*/
285 static void disconnect_client(struct client *c);
287 /* Notification that output has been written. If successful, re-enable the
288 * input buffer and prepare for another query.
290 static void done_client_write(int err, void *p)
292 struct client *c = p;
295 selbuf_enable(&c->b);
297 logmsg(&c->q, LOG_ERR, "failed to send reply: %s", strerror(err));
298 disconnect_client(c);
302 /* Format the message FMT and queue it to be sent to the client. Client
303 * input will be disabled until the write completes.
305 static void PRINTF_LIKE(2, 3)
306 write_to_client(struct client *c, const char *fmt, ...)
313 n = vsnprintf(buf, sizeof(buf), fmt, ap);
315 logmsg(&c->q, LOG_ERR, "failed to format output: %s", strerror(errno));
316 disconnect_client(c);
318 } else if (n > sizeof(buf)) {
319 logmsg(&c->q, LOG_ERR, "output too long for client send buffer");
320 disconnect_client(c);
324 selbuf_disable(&c->b);
325 if (queue_write(&c->wb, buf, n)) {
326 logmsg(&c->q, LOG_ERR, "write buffer overflow");
327 disconnect_client(c);
331 /* Format a reply to the client, with the form LPORT:RPORT:TY:TOK0[:TOK1].
332 * Typically, TY will be `ERROR' or `USERID'. In the former case, TOK0 will
333 * be the error token and TOK1 will be null; in the latter case, TOK0 will be
334 * the operating system and TOK1 the user name.
336 static void reply(struct client *c, const char *ty,
337 const char *tok0, const char *tok1)
339 write_to_client(c, "%u,%u:%s:%s%s%s\r\n",
340 c->q.s[L].port, c->q.s[R].port, ty,
341 tok0, tok1 ? ":" : "", tok1 ? tok1 : "");
344 /* Mapping from error codes to their protocol tokens. */
345 const char *const errtok[] = {
346 #define DEFTOK(err, tok) tok,
351 /* Report an error with code ERR to the client. */
352 static void reply_error(struct client *c, unsigned err)
354 assert(err < E_LIMIT);
355 reply(c, "ERROR", errtok[err], 0);
358 /*----- NAT proxy functions -----------------------------------------------*/
360 /* Cancel the proxy operation PX, closing the connection and releasing
361 * resources. This is used for both normal and unexpected closures.
363 static void cancel_proxy(struct proxy *px)
369 selbuf_disable(&px->b);
372 selbuf_enable(&px->c->b);
373 px->next = dead_proxies;
377 /* Delayed destruction of unsafe parts of proxies. */
378 static void reap_dead_proxies(void)
380 struct proxy *px, *pp;
382 for (px = dead_proxies; px; px = pp) {
385 selbuf_destroy(&px->b);
386 free_writebuf(&px->wb);
393 /* Notification that a line (presumably a reply) has been received from the
394 * server. We should check it, log it, and propagate the answer back.
395 * Whatever happens, this proxy operation is now complete.
397 static void proxy_line(char *line, size_t sz, void *p)
399 struct proxy *px = p;
401 const char *q = line;
404 /* Trim trailing space. */
405 while (sz && isspace((unsigned char)line[sz - 1])) sz--;
407 /* Parse the port numbers. These should match the request. */
408 if (unum(&q, &lp, 1, 65535)) goto syntax;
409 skipws(&q); if (*q != ',') goto syntax; q++;
410 if (unum(&q, &rp, 1, 65535)) goto syntax;
411 skipws(&q); if (*q != ':') goto syntax; q++;
412 if (lp != px->c->q.u.nat.port || rp != px->c->q.s[R].port) goto syntax;
414 /* Find out what kind of reply this is. */
415 if (idtoken(&q, buf, sizeof(buf))) goto syntax;
416 skipws(&q); if (*q != ':') goto syntax; q++;
418 if (strcmp(buf, "ERROR") == 0) {
420 /* Report the error without interpreting it. It might be meaningful to
424 logmsg(&px->c->q, LOG_ERR, "proxy error from %s: %s", px->nat, q);
425 reply(px->c, "ERROR", q, 0);
427 } else if (strcmp(buf, "USERID") == 0) {
429 /* Parse out the operating system and user name, and pass them on. */
430 if (idtoken(&q, buf, sizeof(buf))) goto syntax;
431 skipws(&q); if (*q != ':') goto syntax; q++;
433 logmsg(&px->c->q, LOG_ERR, "user `%s'; proxy = %s, os = %s",
435 reply(px->c, "USERID", buf, q);
442 /* We didn't understand the message from the client. */
443 logmsg(&px->c->q, LOG_ERR, "failed to parse response from %s", px->nat);
444 reply_error(px->c, E_UNKNOWN);
446 /* All finished, no matter what. */
450 /* Notification that we have written the query to the server. Await a
451 * response if successful.
453 static void done_proxy_write(int err, void *p)
455 struct proxy *px = p;
458 logmsg(&px->c->q, LOG_ERR, "failed to proxy query to %s: %s",
459 px->nat, strerror(errno));
460 reply_error(px->c, E_UNKNOWN);
464 selbuf_enable(&px->b);
467 /* Notification that the connection to the server is either established or
468 * failed. In the former case, queue the right query.
470 static void proxy_connected(int fd, void *p)
472 struct proxy *px = p;
476 /* If the connection failed then report the problem and give up. */
478 logmsg(&px->c->q, LOG_ERR,
479 "failed to make %s proxy connection to %s: %s",
480 px->c->l->ao->name, px->nat, strerror(errno));
481 reply_error(px->c, E_UNKNOWN);
486 /* We're now ready to go, so set things up. */
488 selbuf_init(&px->b, &sel, fd, proxy_line, px);
489 selbuf_setsize(&px->b, 1024);
490 selbuf_disable(&px->b);
491 init_writebuf(&px->wb, fd, done_proxy_write, px);
493 /* Write the query. This buffer is large enough because we've already
494 * range-checked the remote the port number and the local one came from the
495 * kernel, which we trust not to do anything stupid.
497 n = sprintf(buf, "%u,%u\r\n", px->c->q.u.nat.port, px->c->q.s[R].port);
498 queue_write(&px->wb, buf, n);
501 /* Proxy the query through to a client machine for which we're providing NAT
504 static void proxy_query(struct client *c)
507 struct sockaddr_storage ss;
512 /* Allocate the context structure for the NAT. */
513 px = xmalloc(sizeof(*px));
515 /* We'll use the client host's address in lots of log messages, so we may
516 * as well format it once and use it over and over.
518 inet_ntop(c->q.ao->af, &c->q.u.nat.addr, px->nat, sizeof(px->nat));
520 /* Create the socket for the connection. */
521 if ((fd = socket(c->q.ao->af, SOCK_STREAM, 0)) < 0) {
522 logmsg(&c->q, LOG_ERR, "failed to make %s socket for proxy: %s",
523 c->l->ao->name, strerror(errno));
526 if (fix_up_socket(fd, "proxy")) goto err_1;
528 /* Set up the connection to the client host. The connection interface is a
529 * bit broken: if the connection completes immediately, then the callback
530 * function is called synchronously, and that might decide to shut
531 * everything down. So we must have fully initialized our context before
532 * calling `conn_init', and mustn't touch it again afterwards -- since the
533 * block may have been freed.
537 c->l->ao->socket_to_sockaddr(&s, &ss, &ssz);
538 selbuf_disable(&c->b);
539 c->px = px; px->c = c;
541 if (conn_init(&px->cn, &sel, fd, (struct sockaddr *)&ss, ssz,
542 proxy_connected, px)) {
543 logmsg(&c->q, LOG_ERR, "failed to make %s proxy connection to %s: %s",
544 c->l->ao->name, px->nat, strerror(errno));
548 /* All ready to go. */
551 /* Tidy up after various kinds of failures. */
553 selbuf_enable(&c->b);
558 reply_error(c, E_UNKNOWN);
561 /*----- Client connection functions ---------------------------------------*/
563 /* Disconnect a client, freeing up any associated resources. */
564 static void disconnect_client(struct client *c)
566 selbuf_disable(&c->b);
569 free_writebuf(&c->wb);
570 if (c->px) cancel_proxy(c->px);
571 c->next = dead_clients;
575 /* Throw away dead clients now that we've reached a safe point in the
578 static void reap_dead_clients(void)
580 struct client *c, *cc;
581 for (c = dead_clients; c; c = cc) {
583 selbuf_destroy(&c->b);
589 /* Time out a client because it's been idle for too long. */
590 static void timeout_client(struct timeval *tv, void *p)
592 struct client *c = p;
593 logmsg(&c->q, LOG_NOTICE, "timing out idle or stuck client");
594 sel_addtimer(&sel, &c->t, tv, timeout_client, 0);
595 disconnect_client(c);
598 /* Reset the client idle timer, as a result of activity. Set EXISTP if
599 * there is an existing timer which needs to be removed.
601 static void reset_client_timer(struct client *c, int existp)
605 gettimeofday(&tv, 0);
607 if (existp) sel_rmtimer(&c->t);
608 sel_addtimer(&sel, &c->t, &tv, timeout_client, c);
611 /* Write a pseudorandom token into the buffer at P, which must have space for
612 * at least TOKENSZ bytes.
614 #define TOKENRANDSZ 8
615 #define TOKENSZ ((4*TOKENRANDSZ + 5)/3)
616 static void user_token(char *p)
621 static const char tokmap[64] =
622 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.-";
624 /* If there's not enough pseudorandom stuff lying around, then read more
627 if (tokenptr + TOKENRANDSZ >= sizeof(tokenbuf)) {
628 fill_random(tokenbuf, sizeof(tokenbuf));
632 /* Now encode the bytes using a slightly tweaked base-64 encoding. Read
633 * bytes into the accumulator and write out characters while there's
636 for (i = 0; i < TOKENRANDSZ; i++) {
637 a = (a << 8) | tokenbuf[tokenptr++]; b += 8;
640 *p++ = tokmap[(a >> b) & 0x3f];
644 /* If there's anything left in the accumulator then flush it out. */
646 *p++ = tokmap[(a << (6 - b)) & 0x3f];
648 /* Null-terminate the token. */
652 /* Notification that a line has been received from the client. Parse it,
653 * find out about the connection it's referring to, apply the relevant
654 * policy rules, and produce a response. This is where almost everything
655 * interesting happens.
657 static void client_line(char *line, size_t len, void *p)
659 struct client *c = p;
661 struct passwd *pw = 0;
662 const struct policy *pol;
664 struct policy upol = POLICY_INIT(A_LIMIT);
665 struct policy_file pf;
669 /* If the connection has closed, then tidy stuff away. */
670 c->q.s[R].addr = c->raddr;
671 c->q.s[L].port = c->q.s[R].port = 0;
673 disconnect_client(c);
677 /* Client activity, so update the timer. */
678 reset_client_timer(c, 1);
680 /* See if the policy file has changed since we last looked. If so, try to
681 * read the new version.
683 if (fwatch_update(&polfw, policyfile)) {
684 logmsg(0, LOG_INFO, "reload master policy file `%s'", policyfile);
685 load_policy_file(policyfile, &policy);
688 /* Read the local and remote port numbers into the query structure. */
690 if (unum(&q, &c->q.s[L].port, 1, 65535)) goto bad;
691 skipws(&q); if (*q != ',') goto bad; q++;
692 if (unum(&q, &c->q.s[R].port, 1, 65535)) goto bad;
693 skipws(&q); if (*q) goto bad;
695 /* Identify the connection. Act on the result. */
700 /* We found a user. Track down the user's password entry, because
701 * we'll want that later. Most of the processing for this case is
704 if ((pw = getpwuid(c->q.u.uid)) == 0) {
705 logmsg(&c->q, LOG_ERR, "no passwd entry for user %d", c->q.u.uid);
706 reply_error(c, E_NOUSER);
712 /* We've acted as a NAT for this connection. Proxy the query through
713 * to the actal client host.
719 /* We failed to identify the connection for some reason. We should
720 * already have logged an error, so there's not much to do here.
722 reply_error(c, c->q.u.error);
726 /* Something happened that we don't understand. */
730 /* Search the table of policy rules to find a match. */
731 for (i = 0; i < DA_LEN(&policy); i++) {
732 pol = &DA(&policy)[i];
733 if (!match_policy(pol, &c->q)) continue;
735 /* If this is something simple, then apply the resulting policy rule. */
736 if (pol->act.act != A_USER) goto match;
738 /* The global policy has decided to let the user have a say, so we must
739 * parse the user file.
742 dstr_putf(&d, "%s/.yaid.policy", pw->pw_dir);
743 if (open_policy_file(&pf, d.buf, "user policy file", &c->q, OPF_NOENTOK))
745 while ((t = read_policy_file(&pf)) < T_ERROR) {
747 /* Give up after 100 lines or if there's an error. If the user's
748 * policy is that complicated, something's gone very wrong. Or there's
749 * too much commentary or something.
752 logmsg(&c->q, LOG_ERR, "%s:%d: user policy file too long",
757 /* If this was a blank line, just go around again. */
758 if (t != T_OK) continue;
760 /* If this isn't a match, go around for the next rule. */
761 if (!match_policy(&pf.p, &c->q)) continue;
763 /* Check that the user is allowed to request this action. If not, see
764 * if there's a more acceptable action later on.
766 if (!(pol->act.u.user & (1 << pf.p.act.act))) {
767 logmsg(&c->q, LOG_ERR,
768 "%s:%d: user action forbidden by global policy",
773 /* We've found a match, so grab it, close the file, and say we're
776 upol = pf.p; pol = &upol;
778 close_policy_file(&pf);
782 close_policy_file(&pf);
786 /* No match: apply the built-in default policy. */
787 pol = &default_policy;
790 switch (pol->act.act) {
793 /* Report the actual user's name. */
794 logmsg(&c->q, LOG_INFO, "user `%s' (%d)", pw->pw_name, c->q.u.uid);
795 reply(c, "USERID", "UNIX", pw->pw_name);
799 /* Report an arbitrary token which we can look up in our log file. */
801 logmsg(&c->q, LOG_INFO, "user `%s' (%d); token = %s",
802 pw->pw_name, c->q.u.uid, buf);
803 reply(c, "USERID", "OTHER", buf);
807 /* Deny that there's anyone there at all. */
808 logmsg(&c->q, LOG_INFO, "user `%s' (%d); denying",
809 pw->pw_name, c->q.u.uid);
813 /* Report the user as being hidden. */
814 logmsg(&c->q, LOG_INFO, "user `%s' (%d); hiding",
815 pw->pw_name, c->q.u.uid);
816 reply_error(c, E_HIDDEN);
820 /* Tell an egregious lie about who the user is. */
821 logmsg(&c->q, LOG_INFO, "user `%s' (%d); lie = `%s'",
822 pw->pw_name, c->q.u.uid, pol->act.u.lie);
823 reply(c, "USERID", "UNIX", pol->act.u.lie);
827 /* Something has gone very wrong. */
836 logmsg(&c->q, LOG_ERR, "failed to parse query from client");
837 disconnect_client(c);
840 /* Notification that a new client has connected. Prepare to read a query. */
841 static void accept_client(int fd, unsigned mode, void *p)
843 struct listen *l = p;
845 struct sockaddr_storage ssr, ssl;
846 size_t ssz = sizeof(ssr);
849 /* Accept the new connection. */
850 if ((sk = accept(fd, (struct sockaddr *)&ssr, &ssz)) < 0) {
851 if (errno != EAGAIN && errno == EWOULDBLOCK) {
852 logmsg(0, LOG_ERR, "failed to accept incoming %s connection: %s",
853 l->ao->name, strerror(errno));
857 if (fix_up_socket(sk, "incoming client")) { close(sk); return; }
859 /* Build a client block and fill it in. */
860 c = xmalloc(sizeof(*c));
864 /* Collect the local and remote addresses. */
865 l->ao->sockaddr_to_addr(&ssr, &c->raddr);
867 if (getsockname(sk, (struct sockaddr *)&ssl, &ssz)) {
869 "failed to read local address for incoming %s connection: %s",
870 l->ao->name, strerror(errno));
875 l->ao->sockaddr_to_addr(&ssl, &c->q.s[L].addr);
876 c->q.s[L].port = c->q.s[R].port = 0;
878 /* Set stuff up for reading the query and sending responses. */
879 selbuf_init(&c->b, &sel, sk, client_line, c);
880 selbuf_setsize(&c->b, 1024);
881 reset_client_timer(c, 0);
884 init_writebuf(&c->wb, sk, done_client_write, c);
887 /*----- Main code ---------------------------------------------------------*/
889 /* Set up a listening socket for the address family described by AO,
892 static int make_listening_socket(const struct addrops *ao, int port)
897 struct sockaddr_storage ss;
901 /* Make the socket. */
902 if ((fd = socket(ao->af, SOCK_STREAM, 0)) < 0) {
903 if (errno == EAFNOSUPPORT) return (-1);
904 die(1, "failed to create %s listening socket: %s",
905 ao->name, strerror(errno));
908 /* Build the appropriate local address. */
911 ao->socket_to_sockaddr(&s, &ss, &ssz);
913 /* Perform any initialization specific to the address type. */
914 if (ao->init_listen_socket(fd)) {
915 die(1, "failed to initialize %s listening socket: %s",
916 ao->name, strerror(errno));
919 /* Bind to the address. */
920 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
921 if (bind(fd, (struct sockaddr *)&ss, ssz)) {
922 die(1, "failed to bind %s listening socket: %s",
923 ao->name, strerror(errno));
926 /* Avoid unpleasant race conditions. */
927 if (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0)) {
928 die(1, "failed to set %s listening socket nonblocking: %s",
929 ao->name, strerror(errno));
932 /* Prepare to listen. */
934 die(1, "failed to listen for %s: %s", ao->name, strerror(errno));
936 /* Make a record of all of this. */
937 l = xmalloc(sizeof(*l));
939 sel_initfile(&sel, &l->f, fd, SEL_READ, accept_client, l);
946 /* Quit because of a fatal signal. */
947 static void NORETURN quit(int sig, void *p)
949 const char *signame = p;
951 logmsg(0, LOG_NOTICE, "shutting down on %s", signame);
952 if (pidfile) unlink(pidfile);
956 /* Answer whether the string pointed to by P consists entirely of digits. */
957 static int numericp(const char *p)
960 if (!isdigit((unsigned char)*p++)) return (0);
964 static void usage(FILE *fp)
966 pquis(fp, "Usage: $ [-Dl] [-G GROUP] [-U USER] [-P FILE] "
967 "[-c FILE] [-p PORT]\n");
970 static void version(FILE *fp)
971 { pquis(fp, "$, version " VERSION "\n"); }
973 static void help(FILE *fp)
975 version(fp); fputc('\n', fp);
978 Yet Another Ident Daemon. Really, the world doesn't need such a thing.\n\
979 It's just a shame none of the others do the right things.\n\
983 -h, --help Show this help message.\n\
984 -v, --version Show the version number.\n\
985 -u, --usage Show a very short usage summary.\n\
987 -D, --daemon Become a daemon, running in the background.\n\
988 -G, --group=GROUP Set group after initialization.\n\
989 -P, --pidfile=FILE Write process id to FILE.\n\
990 -U, --user=USER Set user after initialization.\n\
991 -c, --config=FILE Read global policy from FILE.\n\
992 -l, --syslog Write log messages using syslog(3).\n\
993 -p, --port=PORT Listen for connections on this port.\n",
997 int main(int argc, char *argv[])
1002 struct passwd *pw = 0;
1005 sig sigint, sigterm;
1011 const struct addrops *ao;
1016 /* Parse command-line options. */
1018 const struct option opts[] = {
1019 { "help", 0, 0, 'h' },
1020 { "version", 0, 0, 'v' },
1021 { "usage", 0, 0, 'u' },
1022 { "daemon", 0, 0, 'D' },
1023 { "group", OPTF_ARGREQ, 0, 'G' },
1024 { "pidfile", OPTF_ARGREQ, 0, 'P' },
1025 { "user", OPTF_ARGREQ, 0, 'U' },
1026 { "config", OPTF_ARGREQ, 0, 'c' },
1027 { "syslog", 0, 0, 'l' },
1028 { "port", OPTF_ARGREQ, 0, 'p' },
1032 if ((i = mdwopt(argc, argv, "hvuDG:P:U:c:lp:", opts, 0, 0, 0)) < 0)
1035 case 'h': help(stdout); exit(0);
1036 case 'v': version(stdout); exit(0);
1037 case 'u': usage(stdout); exit(0);
1038 case 'D': f |= f_daemon; break;
1039 case 'P': pidfile = optarg; break;
1040 case 'c': policyfile = optarg; break;
1041 case 'l': flags |= F_SYSLOG; break;
1043 if (numericp(optarg))
1045 else if ((gr = getgrnam(optarg)) == 0)
1046 die(1, "unknown group `%s'", optarg);
1051 if (numericp(optarg))
1053 else if ((pw = getpwnam(optarg)) == 0)
1054 die(1, "unknown user `%s'", optarg);
1059 if (numericp(optarg))
1060 port = atoi(optarg);
1061 else if ((s = getservbyname(optarg, "tcp")) == 0)
1062 die(1, "unknown service name `%s'", optarg);
1064 port = ntohs(s->s_port);
1066 default: f |= f_bogus; break;
1069 if (optind < argc) f |= f_bogus;
1070 if (f & f_bogus) { usage(stderr); exit(1); }
1072 /* If a user has been requested, but no group, then find the user's primary
1073 * group. If the user was given by name, then we already have a password
1074 * entry and should use that, in case two differently-named users have the
1075 * same uid but distinct gids.
1077 if (u != -1 && g == -1) {
1078 if (!pw && (pw = getpwuid(u)) == 0) {
1079 die(1, "failed to find password entry for user %d: "
1080 "request group explicitly", u);
1085 /* Initialize system-specific machinery. */
1088 /* Load the global policy rules. */
1089 fwatch_init(&polfw, policyfile);
1090 if (load_policy_file(policyfile, &policy))
1093 /* Set up the I/O event system. */
1096 /* Watch for some interesting signals. */
1098 sig_add(&sigint, SIGINT, quit, "SIGINT");
1099 sig_add(&sigterm, SIGTERM, quit, "SIGTERM");
1101 /* Listen for incoming connections. */
1102 for (ao = addroptab; ao->name; ao++)
1103 if (!make_listening_socket(ao, port)) any = 1;
1104 if (!any) die(1, "no IP protocols supported");
1106 /* Open the pidfile now, in case it's somewhere we can't write. */
1107 if (pidfile && (fp = fopen(pidfile, "w")) == 0) {
1108 die(1, "failed to open pidfile `%s' for writing: %s",
1109 pidfile, strerror(errno));
1112 /* If we're meant to use syslog, then open the log. */
1113 if (flags & F_SYSLOG)
1114 openlog(QUIS, 0, LOG_DAEMON);
1116 /* Drop privileges. */
1117 if ((g != -1 && (setegid(g) || setgid(g) ||
1118 (getuid() == 0 && setgroups(1, &g)))) ||
1119 (u != -1 && setuid(u)))
1120 die(1, "failed to drop privileges: %s", strerror(errno));
1122 /* Become a background process, if requested. */
1123 if ((f & f_daemon) && daemonize())
1124 die(1, "failed to become daemon: %s", strerror(errno));
1126 /* Write the process id to the pidfile. */
1128 fprintf(fp, "%d\n", getpid());
1132 /* And now we're going. */
1135 /* Read events and process them. */
1137 if (sel_select(&sel) && errno != EINTR)
1138 die(1, "select failed: %s", strerror(errno));
1139 reap_dead_proxies();
1140 reap_dead_clients();
1143 /* This just keeps the compiler happy. */
1147 /*----- That's all, folks -------------------------------------------------*/