Provide git_config with a callback-data parameter
[git/git.git] / daemon.c
1 #include "cache.h"
2 #include "pkt-line.h"
3 #include "exec_cmd.h"
4 #include "interpolate.h"
5
6 #include <syslog.h>
7
8 #ifndef HOST_NAME_MAX
9 #define HOST_NAME_MAX 256
10 #endif
11
12 #ifndef NI_MAXSERV
13 #define NI_MAXSERV 32
14 #endif
15
16 static int log_syslog;
17 static int verbose;
18 static int reuseaddr;
19
20 static const char daemon_usage[] =
21 "git-daemon [--verbose] [--syslog] [--export-all]\n"
22 " [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
23 " [--base-path=path] [--base-path-relaxed]\n"
24 " [--user-path | --user-path=path]\n"
25 " [--interpolated-path=path]\n"
26 " [--reuseaddr] [--detach] [--pid-file=file]\n"
27 " [--[enable|disable|allow-override|forbid-override]=service]\n"
28 " [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
29 " [--user=user [--group=group]]\n"
30 " [directory...]";
31
32 /* List of acceptable pathname prefixes */
33 static char **ok_paths;
34 static int strict_paths;
35
36 /* If this is set, git-daemon-export-ok is not required */
37 static int export_all_trees;
38
39 /* Take all paths relative to this one if non-NULL */
40 static char *base_path;
41 static char *interpolated_path;
42 static int base_path_relaxed;
43
44 /* Flag indicating client sent extra args. */
45 static int saw_extended_args;
46
47 /* If defined, ~user notation is allowed and the string is inserted
48 * after ~user/. E.g. a request to git://host/~alice/frotz would
49 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
50 */
51 static const char *user_path;
52
53 /* Timeout, and initial timeout */
54 static unsigned int timeout;
55 static unsigned int init_timeout;
56
57 /*
58 * Static table for now. Ugh.
59 * Feel free to make dynamic as needed.
60 */
61 #define INTERP_SLOT_HOST (0)
62 #define INTERP_SLOT_CANON_HOST (1)
63 #define INTERP_SLOT_IP (2)
64 #define INTERP_SLOT_PORT (3)
65 #define INTERP_SLOT_DIR (4)
66 #define INTERP_SLOT_PERCENT (5)
67
68 static struct interp interp_table[] = {
69 { "%H", 0},
70 { "%CH", 0},
71 { "%IP", 0},
72 { "%P", 0},
73 { "%D", 0},
74 { "%%", 0},
75 };
76
77
78 static void logreport(int priority, const char *err, va_list params)
79 {
80 /* We should do a single write so that it is atomic and output
81 * of several processes do not get intermingled. */
82 char buf[1024];
83 int buflen;
84 int maxlen, msglen;
85
86 /* sizeof(buf) should be big enough for "[pid] \n" */
87 buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
88
89 maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
90 msglen = vsnprintf(buf + buflen, maxlen, err, params);
91
92 if (log_syslog) {
93 syslog(priority, "%s", buf);
94 return;
95 }
96
97 /* maxlen counted our own LF but also counts space given to
98 * vsnprintf for the terminating NUL. We want to make sure that
99 * we have space for our own LF and NUL after the "meat" of the
100 * message, so truncate it at maxlen - 1.
101 */
102 if (msglen > maxlen - 1)
103 msglen = maxlen - 1;
104 else if (msglen < 0)
105 msglen = 0; /* Protect against weird return values. */
106 buflen += msglen;
107
108 buf[buflen++] = '\n';
109 buf[buflen] = '\0';
110
111 write_in_full(2, buf, buflen);
112 }
113
114 static void logerror(const char *err, ...)
115 {
116 va_list params;
117 va_start(params, err);
118 logreport(LOG_ERR, err, params);
119 va_end(params);
120 }
121
122 static void loginfo(const char *err, ...)
123 {
124 va_list params;
125 if (!verbose)
126 return;
127 va_start(params, err);
128 logreport(LOG_INFO, err, params);
129 va_end(params);
130 }
131
132 static void NORETURN daemon_die(const char *err, va_list params)
133 {
134 logreport(LOG_ERR, err, params);
135 exit(1);
136 }
137
138 static int avoid_alias(char *p)
139 {
140 int sl, ndot;
141
142 /*
143 * This resurrects the belts and suspenders paranoia check by HPA
144 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
145 * does not do getcwd() based path canonicalizations.
146 *
147 * sl becomes true immediately after seeing '/' and continues to
148 * be true as long as dots continue after that without intervening
149 * non-dot character.
150 */
151 if (!p || (*p != '/' && *p != '~'))
152 return -1;
153 sl = 1; ndot = 0;
154 p++;
155
156 while (1) {
157 char ch = *p++;
158 if (sl) {
159 if (ch == '.')
160 ndot++;
161 else if (ch == '/') {
162 if (ndot < 3)
163 /* reject //, /./ and /../ */
164 return -1;
165 ndot = 0;
166 }
167 else if (ch == 0) {
168 if (0 < ndot && ndot < 3)
169 /* reject /.$ and /..$ */
170 return -1;
171 return 0;
172 }
173 else
174 sl = ndot = 0;
175 }
176 else if (ch == 0)
177 return 0;
178 else if (ch == '/') {
179 sl = 1;
180 ndot = 0;
181 }
182 }
183 }
184
185 static char *path_ok(struct interp *itable)
186 {
187 static char rpath[PATH_MAX];
188 static char interp_path[PATH_MAX];
189 int retried_path = 0;
190 char *path;
191 char *dir;
192
193 dir = itable[INTERP_SLOT_DIR].value;
194
195 if (avoid_alias(dir)) {
196 logerror("'%s': aliased", dir);
197 return NULL;
198 }
199
200 if (*dir == '~') {
201 if (!user_path) {
202 logerror("'%s': User-path not allowed", dir);
203 return NULL;
204 }
205 if (*user_path) {
206 /* Got either "~alice" or "~alice/foo";
207 * rewrite them to "~alice/%s" or
208 * "~alice/%s/foo".
209 */
210 int namlen, restlen = strlen(dir);
211 char *slash = strchr(dir, '/');
212 if (!slash)
213 slash = dir + restlen;
214 namlen = slash - dir;
215 restlen -= namlen;
216 loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
217 snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
218 namlen, dir, user_path, restlen, slash);
219 dir = rpath;
220 }
221 }
222 else if (interpolated_path && saw_extended_args) {
223 if (*dir != '/') {
224 /* Allow only absolute */
225 logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
226 return NULL;
227 }
228
229 interpolate(interp_path, PATH_MAX, interpolated_path,
230 interp_table, ARRAY_SIZE(interp_table));
231 loginfo("Interpolated dir '%s'", interp_path);
232
233 dir = interp_path;
234 }
235 else if (base_path) {
236 if (*dir != '/') {
237 /* Allow only absolute */
238 logerror("'%s': Non-absolute path denied (base-path active)", dir);
239 return NULL;
240 }
241 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
242 dir = rpath;
243 }
244
245 do {
246 path = enter_repo(dir, strict_paths);
247 if (path)
248 break;
249
250 /*
251 * if we fail and base_path_relaxed is enabled, try without
252 * prefixing the base path
253 */
254 if (base_path && base_path_relaxed && !retried_path) {
255 dir = itable[INTERP_SLOT_DIR].value;
256 retried_path = 1;
257 continue;
258 }
259 break;
260 } while (1);
261
262 if (!path) {
263 logerror("'%s': unable to chdir or not a git archive", dir);
264 return NULL;
265 }
266
267 if ( ok_paths && *ok_paths ) {
268 char **pp;
269 int pathlen = strlen(path);
270
271 /* The validation is done on the paths after enter_repo
272 * appends optional {.git,.git/.git} and friends, but
273 * it does not use getcwd(). So if your /pub is
274 * a symlink to /mnt/pub, you can whitelist /pub and
275 * do not have to say /mnt/pub.
276 * Do not say /pub/.
277 */
278 for ( pp = ok_paths ; *pp ; pp++ ) {
279 int len = strlen(*pp);
280 if (len <= pathlen &&
281 !memcmp(*pp, path, len) &&
282 (path[len] == '\0' ||
283 (!strict_paths && path[len] == '/')))
284 return path;
285 }
286 }
287 else {
288 /* be backwards compatible */
289 if (!strict_paths)
290 return path;
291 }
292
293 logerror("'%s': not in whitelist", path);
294 return NULL; /* Fallthrough. Deny by default */
295 }
296
297 typedef int (*daemon_service_fn)(void);
298 struct daemon_service {
299 const char *name;
300 const char *config_name;
301 daemon_service_fn fn;
302 int enabled;
303 int overridable;
304 };
305
306 static struct daemon_service *service_looking_at;
307 static int service_enabled;
308
309 static int git_daemon_config(const char *var, const char *value, void *cb)
310 {
311 if (!prefixcmp(var, "daemon.") &&
312 !strcmp(var + 7, service_looking_at->config_name)) {
313 service_enabled = git_config_bool(var, value);
314 return 0;
315 }
316
317 /* we are not interested in parsing any other configuration here */
318 return 0;
319 }
320
321 static int run_service(struct interp *itable, struct daemon_service *service)
322 {
323 const char *path;
324 int enabled = service->enabled;
325
326 loginfo("Request %s for '%s'",
327 service->name,
328 itable[INTERP_SLOT_DIR].value);
329
330 if (!enabled && !service->overridable) {
331 logerror("'%s': service not enabled.", service->name);
332 errno = EACCES;
333 return -1;
334 }
335
336 if (!(path = path_ok(itable)))
337 return -1;
338
339 /*
340 * Security on the cheap.
341 *
342 * We want a readable HEAD, usable "objects" directory, and
343 * a "git-daemon-export-ok" flag that says that the other side
344 * is ok with us doing this.
345 *
346 * path_ok() uses enter_repo() and does whitelist checking.
347 * We only need to make sure the repository is exported.
348 */
349
350 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
351 logerror("'%s': repository not exported.", path);
352 errno = EACCES;
353 return -1;
354 }
355
356 if (service->overridable) {
357 service_looking_at = service;
358 service_enabled = -1;
359 git_config(git_daemon_config, NULL);
360 if (0 <= service_enabled)
361 enabled = service_enabled;
362 }
363 if (!enabled) {
364 logerror("'%s': service not enabled for '%s'",
365 service->name, path);
366 errno = EACCES;
367 return -1;
368 }
369
370 /*
371 * We'll ignore SIGTERM from now on, we have a
372 * good client.
373 */
374 signal(SIGTERM, SIG_IGN);
375
376 return service->fn();
377 }
378
379 static int upload_pack(void)
380 {
381 /* Timeout as string */
382 char timeout_buf[64];
383
384 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
385
386 /* git-upload-pack only ever reads stuff, so this is safe */
387 execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
388 return -1;
389 }
390
391 static int upload_archive(void)
392 {
393 execl_git_cmd("upload-archive", ".", NULL);
394 return -1;
395 }
396
397 static int receive_pack(void)
398 {
399 execl_git_cmd("receive-pack", ".", NULL);
400 return -1;
401 }
402
403 static struct daemon_service daemon_service[] = {
404 { "upload-archive", "uploadarch", upload_archive, 0, 1 },
405 { "upload-pack", "uploadpack", upload_pack, 1, 1 },
406 { "receive-pack", "receivepack", receive_pack, 0, 1 },
407 };
408
409 static void enable_service(const char *name, int ena)
410 {
411 int i;
412 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
413 if (!strcmp(daemon_service[i].name, name)) {
414 daemon_service[i].enabled = ena;
415 return;
416 }
417 }
418 die("No such service %s", name);
419 }
420
421 static void make_service_overridable(const char *name, int ena)
422 {
423 int i;
424 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
425 if (!strcmp(daemon_service[i].name, name)) {
426 daemon_service[i].overridable = ena;
427 return;
428 }
429 }
430 die("No such service %s", name);
431 }
432
433 /*
434 * Separate the "extra args" information as supplied by the client connection.
435 * Any resulting data is squirreled away in the given interpolation table.
436 */
437 static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
438 {
439 char *val;
440 int vallen;
441 char *end = extra_args + buflen;
442
443 while (extra_args < end && *extra_args) {
444 saw_extended_args = 1;
445 if (strncasecmp("host=", extra_args, 5) == 0) {
446 val = extra_args + 5;
447 vallen = strlen(val) + 1;
448 if (*val) {
449 /* Split <host>:<port> at colon. */
450 char *host = val;
451 char *port = strrchr(host, ':');
452 if (port) {
453 *port = 0;
454 port++;
455 interp_set_entry(table, INTERP_SLOT_PORT, port);
456 }
457 interp_set_entry(table, INTERP_SLOT_HOST, host);
458 }
459
460 /* On to the next one */
461 extra_args = val + vallen;
462 }
463 }
464 }
465
466 static void fill_in_extra_table_entries(struct interp *itable)
467 {
468 char *hp;
469
470 /*
471 * Replace literal host with lowercase-ized hostname.
472 */
473 hp = interp_table[INTERP_SLOT_HOST].value;
474 if (!hp)
475 return;
476 for ( ; *hp; hp++)
477 *hp = tolower(*hp);
478
479 /*
480 * Locate canonical hostname and its IP address.
481 */
482 #ifndef NO_IPV6
483 {
484 struct addrinfo hints;
485 struct addrinfo *ai, *ai0;
486 int gai;
487 static char addrbuf[HOST_NAME_MAX + 1];
488
489 memset(&hints, 0, sizeof(hints));
490 hints.ai_flags = AI_CANONNAME;
491
492 gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
493 if (!gai) {
494 for (ai = ai0; ai; ai = ai->ai_next) {
495 struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
496
497 inet_ntop(AF_INET, &sin_addr->sin_addr,
498 addrbuf, sizeof(addrbuf));
499 interp_set_entry(interp_table,
500 INTERP_SLOT_CANON_HOST, ai->ai_canonname);
501 interp_set_entry(interp_table,
502 INTERP_SLOT_IP, addrbuf);
503 break;
504 }
505 freeaddrinfo(ai0);
506 }
507 }
508 #else
509 {
510 struct hostent *hent;
511 struct sockaddr_in sa;
512 char **ap;
513 static char addrbuf[HOST_NAME_MAX + 1];
514
515 hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
516
517 ap = hent->h_addr_list;
518 memset(&sa, 0, sizeof sa);
519 sa.sin_family = hent->h_addrtype;
520 sa.sin_port = htons(0);
521 memcpy(&sa.sin_addr, *ap, hent->h_length);
522
523 inet_ntop(hent->h_addrtype, &sa.sin_addr,
524 addrbuf, sizeof(addrbuf));
525
526 interp_set_entry(interp_table, INTERP_SLOT_CANON_HOST, hent->h_name);
527 interp_set_entry(interp_table, INTERP_SLOT_IP, addrbuf);
528 }
529 #endif
530 }
531
532
533 static int execute(struct sockaddr *addr)
534 {
535 static char line[1000];
536 int pktlen, len, i;
537
538 if (addr) {
539 char addrbuf[256] = "";
540 int port = -1;
541
542 if (addr->sa_family == AF_INET) {
543 struct sockaddr_in *sin_addr = (void *) addr;
544 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
545 port = ntohs(sin_addr->sin_port);
546 #ifndef NO_IPV6
547 } else if (addr && addr->sa_family == AF_INET6) {
548 struct sockaddr_in6 *sin6_addr = (void *) addr;
549
550 char *buf = addrbuf;
551 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
552 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
553 strcat(buf, "]");
554
555 port = ntohs(sin6_addr->sin6_port);
556 #endif
557 }
558 loginfo("Connection from %s:%d", addrbuf, port);
559 }
560
561 alarm(init_timeout ? init_timeout : timeout);
562 pktlen = packet_read_line(0, line, sizeof(line));
563 alarm(0);
564
565 len = strlen(line);
566 if (pktlen != len)
567 loginfo("Extended attributes (%d bytes) exist <%.*s>",
568 (int) pktlen - len,
569 (int) pktlen - len, line + len + 1);
570 if (len && line[len-1] == '\n') {
571 line[--len] = 0;
572 pktlen--;
573 }
574
575 /*
576 * Initialize the path interpolation table for this connection.
577 */
578 interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
579 interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
580
581 if (len != pktlen) {
582 parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
583 fill_in_extra_table_entries(interp_table);
584 }
585
586 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
587 struct daemon_service *s = &(daemon_service[i]);
588 int namelen = strlen(s->name);
589 if (!prefixcmp(line, "git-") &&
590 !strncmp(s->name, line + 4, namelen) &&
591 line[namelen + 4] == ' ') {
592 /*
593 * Note: The directory here is probably context sensitive,
594 * and might depend on the actual service being performed.
595 */
596 interp_set_entry(interp_table,
597 INTERP_SLOT_DIR, line + namelen + 5);
598 return run_service(interp_table, s);
599 }
600 }
601
602 logerror("Protocol error: '%s'", line);
603 return -1;
604 }
605
606
607 /*
608 * We count spawned/reaped separately, just to avoid any
609 * races when updating them from signals. The SIGCHLD handler
610 * will only update children_reaped, and the fork logic will
611 * only update children_spawned.
612 *
613 * MAX_CHILDREN should be a power-of-two to make the modulus
614 * operation cheap. It should also be at least twice
615 * the maximum number of connections we will ever allow.
616 */
617 #define MAX_CHILDREN 128
618
619 static int max_connections = 25;
620
621 /* These are updated by the signal handler */
622 static volatile unsigned int children_reaped;
623 static pid_t dead_child[MAX_CHILDREN];
624
625 /* These are updated by the main loop */
626 static unsigned int children_spawned;
627 static unsigned int children_deleted;
628
629 static struct child {
630 pid_t pid;
631 int addrlen;
632 struct sockaddr_storage address;
633 } live_child[MAX_CHILDREN];
634
635 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
636 {
637 live_child[idx].pid = pid;
638 live_child[idx].addrlen = addrlen;
639 memcpy(&live_child[idx].address, addr, addrlen);
640 }
641
642 /*
643 * Walk from "deleted" to "spawned", and remove child "pid".
644 *
645 * We move everything up by one, since the new "deleted" will
646 * be one higher.
647 */
648 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
649 {
650 struct child n;
651
652 deleted %= MAX_CHILDREN;
653 spawned %= MAX_CHILDREN;
654 if (live_child[deleted].pid == pid) {
655 live_child[deleted].pid = -1;
656 return;
657 }
658 n = live_child[deleted];
659 for (;;) {
660 struct child m;
661 deleted = (deleted + 1) % MAX_CHILDREN;
662 if (deleted == spawned)
663 die("could not find dead child %d\n", pid);
664 m = live_child[deleted];
665 live_child[deleted] = n;
666 if (m.pid == pid)
667 return;
668 n = m;
669 }
670 }
671
672 /*
673 * This gets called if the number of connections grows
674 * past "max_connections".
675 *
676 * We _should_ start off by searching for connections
677 * from the same IP, and if there is some address wth
678 * multiple connections, we should kill that first.
679 *
680 * As it is, we just "randomly" kill 25% of the connections,
681 * and our pseudo-random generator sucks too. I have no
682 * shame.
683 *
684 * Really, this is just a place-holder for a _real_ algorithm.
685 */
686 static void kill_some_children(int signo, unsigned start, unsigned stop)
687 {
688 start %= MAX_CHILDREN;
689 stop %= MAX_CHILDREN;
690 while (start != stop) {
691 if (!(start & 3))
692 kill(live_child[start].pid, signo);
693 start = (start + 1) % MAX_CHILDREN;
694 }
695 }
696
697 static void check_max_connections(void)
698 {
699 for (;;) {
700 int active;
701 unsigned spawned, reaped, deleted;
702
703 spawned = children_spawned;
704 reaped = children_reaped;
705 deleted = children_deleted;
706
707 while (deleted < reaped) {
708 pid_t pid = dead_child[deleted % MAX_CHILDREN];
709 remove_child(pid, deleted, spawned);
710 deleted++;
711 }
712 children_deleted = deleted;
713
714 active = spawned - deleted;
715 if (active <= max_connections)
716 break;
717
718 /* Kill some unstarted connections with SIGTERM */
719 kill_some_children(SIGTERM, deleted, spawned);
720 if (active <= max_connections << 1)
721 break;
722
723 /* If the SIGTERM thing isn't helping use SIGKILL */
724 kill_some_children(SIGKILL, deleted, spawned);
725 sleep(1);
726 }
727 }
728
729 static void handle(int incoming, struct sockaddr *addr, int addrlen)
730 {
731 pid_t pid = fork();
732
733 if (pid) {
734 unsigned idx;
735
736 close(incoming);
737 if (pid < 0)
738 return;
739
740 idx = children_spawned % MAX_CHILDREN;
741 children_spawned++;
742 add_child(idx, pid, addr, addrlen);
743
744 check_max_connections();
745 return;
746 }
747
748 dup2(incoming, 0);
749 dup2(incoming, 1);
750 close(incoming);
751
752 exit(execute(addr));
753 }
754
755 static void child_handler(int signo)
756 {
757 for (;;) {
758 int status;
759 pid_t pid = waitpid(-1, &status, WNOHANG);
760
761 if (pid > 0) {
762 unsigned reaped = children_reaped;
763 dead_child[reaped % MAX_CHILDREN] = pid;
764 children_reaped = reaped + 1;
765 /* XXX: Custom logging, since we don't wanna getpid() */
766 if (verbose) {
767 const char *dead = "";
768 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
769 dead = " (with error)";
770 if (log_syslog)
771 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
772 else
773 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
774 }
775 continue;
776 }
777 break;
778 }
779 }
780
781 static int set_reuse_addr(int sockfd)
782 {
783 int on = 1;
784
785 if (!reuseaddr)
786 return 0;
787 return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
788 &on, sizeof(on));
789 }
790
791 #ifndef NO_IPV6
792
793 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
794 {
795 int socknum = 0, *socklist = NULL;
796 int maxfd = -1;
797 char pbuf[NI_MAXSERV];
798 struct addrinfo hints, *ai0, *ai;
799 int gai;
800 long flags;
801
802 sprintf(pbuf, "%d", listen_port);
803 memset(&hints, 0, sizeof(hints));
804 hints.ai_family = AF_UNSPEC;
805 hints.ai_socktype = SOCK_STREAM;
806 hints.ai_protocol = IPPROTO_TCP;
807 hints.ai_flags = AI_PASSIVE;
808
809 gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
810 if (gai)
811 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
812
813 for (ai = ai0; ai; ai = ai->ai_next) {
814 int sockfd;
815
816 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
817 if (sockfd < 0)
818 continue;
819 if (sockfd >= FD_SETSIZE) {
820 error("too large socket descriptor.");
821 close(sockfd);
822 continue;
823 }
824
825 #ifdef IPV6_V6ONLY
826 if (ai->ai_family == AF_INET6) {
827 int on = 1;
828 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
829 &on, sizeof(on));
830 /* Note: error is not fatal */
831 }
832 #endif
833
834 if (set_reuse_addr(sockfd)) {
835 close(sockfd);
836 continue;
837 }
838
839 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
840 close(sockfd);
841 continue; /* not fatal */
842 }
843 if (listen(sockfd, 5) < 0) {
844 close(sockfd);
845 continue; /* not fatal */
846 }
847
848 flags = fcntl(sockfd, F_GETFD, 0);
849 if (flags >= 0)
850 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
851
852 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
853 socklist[socknum++] = sockfd;
854
855 if (maxfd < sockfd)
856 maxfd = sockfd;
857 }
858
859 freeaddrinfo(ai0);
860
861 *socklist_p = socklist;
862 return socknum;
863 }
864
865 #else /* NO_IPV6 */
866
867 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
868 {
869 struct sockaddr_in sin;
870 int sockfd;
871 long flags;
872
873 memset(&sin, 0, sizeof sin);
874 sin.sin_family = AF_INET;
875 sin.sin_port = htons(listen_port);
876
877 if (listen_addr) {
878 /* Well, host better be an IP address here. */
879 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
880 return 0;
881 } else {
882 sin.sin_addr.s_addr = htonl(INADDR_ANY);
883 }
884
885 sockfd = socket(AF_INET, SOCK_STREAM, 0);
886 if (sockfd < 0)
887 return 0;
888
889 if (set_reuse_addr(sockfd)) {
890 close(sockfd);
891 return 0;
892 }
893
894 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
895 close(sockfd);
896 return 0;
897 }
898
899 if (listen(sockfd, 5) < 0) {
900 close(sockfd);
901 return 0;
902 }
903
904 flags = fcntl(sockfd, F_GETFD, 0);
905 if (flags >= 0)
906 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
907
908 *socklist_p = xmalloc(sizeof(int));
909 **socklist_p = sockfd;
910 return 1;
911 }
912
913 #endif
914
915 static int service_loop(int socknum, int *socklist)
916 {
917 struct pollfd *pfd;
918 int i;
919
920 pfd = xcalloc(socknum, sizeof(struct pollfd));
921
922 for (i = 0; i < socknum; i++) {
923 pfd[i].fd = socklist[i];
924 pfd[i].events = POLLIN;
925 }
926
927 signal(SIGCHLD, child_handler);
928
929 for (;;) {
930 int i;
931
932 if (poll(pfd, socknum, -1) < 0) {
933 if (errno != EINTR) {
934 error("poll failed, resuming: %s",
935 strerror(errno));
936 sleep(1);
937 }
938 continue;
939 }
940
941 for (i = 0; i < socknum; i++) {
942 if (pfd[i].revents & POLLIN) {
943 struct sockaddr_storage ss;
944 unsigned int sslen = sizeof(ss);
945 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
946 if (incoming < 0) {
947 switch (errno) {
948 case EAGAIN:
949 case EINTR:
950 case ECONNABORTED:
951 continue;
952 default:
953 die("accept returned %s", strerror(errno));
954 }
955 }
956 handle(incoming, (struct sockaddr *)&ss, sslen);
957 }
958 }
959 }
960 }
961
962 /* if any standard file descriptor is missing open it to /dev/null */
963 static void sanitize_stdfds(void)
964 {
965 int fd = open("/dev/null", O_RDWR, 0);
966 while (fd != -1 && fd < 2)
967 fd = dup(fd);
968 if (fd == -1)
969 die("open /dev/null or dup failed: %s", strerror(errno));
970 if (fd > 2)
971 close(fd);
972 }
973
974 static void daemonize(void)
975 {
976 switch (fork()) {
977 case 0:
978 break;
979 case -1:
980 die("fork failed: %s", strerror(errno));
981 default:
982 exit(0);
983 }
984 if (setsid() == -1)
985 die("setsid failed: %s", strerror(errno));
986 close(0);
987 close(1);
988 close(2);
989 sanitize_stdfds();
990 }
991
992 static void store_pid(const char *path)
993 {
994 FILE *f = fopen(path, "w");
995 if (!f)
996 die("cannot open pid file %s: %s", path, strerror(errno));
997 if (fprintf(f, "%d\n", getpid()) < 0 || fclose(f) != 0)
998 die("failed to write pid file %s: %s", path, strerror(errno));
999 }
1000
1001 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
1002 {
1003 int socknum, *socklist;
1004
1005 socknum = socksetup(listen_addr, listen_port, &socklist);
1006 if (socknum == 0)
1007 die("unable to allocate any listen sockets on host %s port %u",
1008 listen_addr, listen_port);
1009
1010 if (pass && gid &&
1011 (initgroups(pass->pw_name, gid) || setgid (gid) ||
1012 setuid(pass->pw_uid)))
1013 die("cannot drop privileges");
1014
1015 return service_loop(socknum, socklist);
1016 }
1017
1018 int main(int argc, char **argv)
1019 {
1020 int listen_port = 0;
1021 char *listen_addr = NULL;
1022 int inetd_mode = 0;
1023 const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1024 int detach = 0;
1025 struct passwd *pass = NULL;
1026 struct group *group;
1027 gid_t gid = 0;
1028 int i;
1029
1030 /* Without this we cannot rely on waitpid() to tell
1031 * what happened to our children.
1032 */
1033 signal(SIGCHLD, SIG_DFL);
1034
1035 for (i = 1; i < argc; i++) {
1036 char *arg = argv[i];
1037
1038 if (!prefixcmp(arg, "--listen=")) {
1039 char *p = arg + 9;
1040 char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
1041 while (*p)
1042 *ph++ = tolower(*p++);
1043 *ph = 0;
1044 continue;
1045 }
1046 if (!prefixcmp(arg, "--port=")) {
1047 char *end;
1048 unsigned long n;
1049 n = strtoul(arg+7, &end, 0);
1050 if (arg[7] && !*end) {
1051 listen_port = n;
1052 continue;
1053 }
1054 }
1055 if (!strcmp(arg, "--inetd")) {
1056 inetd_mode = 1;
1057 log_syslog = 1;
1058 continue;
1059 }
1060 if (!strcmp(arg, "--verbose")) {
1061 verbose = 1;
1062 continue;
1063 }
1064 if (!strcmp(arg, "--syslog")) {
1065 log_syslog = 1;
1066 continue;
1067 }
1068 if (!strcmp(arg, "--export-all")) {
1069 export_all_trees = 1;
1070 continue;
1071 }
1072 if (!prefixcmp(arg, "--timeout=")) {
1073 timeout = atoi(arg+10);
1074 continue;
1075 }
1076 if (!prefixcmp(arg, "--init-timeout=")) {
1077 init_timeout = atoi(arg+15);
1078 continue;
1079 }
1080 if (!strcmp(arg, "--strict-paths")) {
1081 strict_paths = 1;
1082 continue;
1083 }
1084 if (!prefixcmp(arg, "--base-path=")) {
1085 base_path = arg+12;
1086 continue;
1087 }
1088 if (!strcmp(arg, "--base-path-relaxed")) {
1089 base_path_relaxed = 1;
1090 continue;
1091 }
1092 if (!prefixcmp(arg, "--interpolated-path=")) {
1093 interpolated_path = arg+20;
1094 continue;
1095 }
1096 if (!strcmp(arg, "--reuseaddr")) {
1097 reuseaddr = 1;
1098 continue;
1099 }
1100 if (!strcmp(arg, "--user-path")) {
1101 user_path = "";
1102 continue;
1103 }
1104 if (!prefixcmp(arg, "--user-path=")) {
1105 user_path = arg + 12;
1106 continue;
1107 }
1108 if (!prefixcmp(arg, "--pid-file=")) {
1109 pid_file = arg + 11;
1110 continue;
1111 }
1112 if (!strcmp(arg, "--detach")) {
1113 detach = 1;
1114 log_syslog = 1;
1115 continue;
1116 }
1117 if (!prefixcmp(arg, "--user=")) {
1118 user_name = arg + 7;
1119 continue;
1120 }
1121 if (!prefixcmp(arg, "--group=")) {
1122 group_name = arg + 8;
1123 continue;
1124 }
1125 if (!prefixcmp(arg, "--enable=")) {
1126 enable_service(arg + 9, 1);
1127 continue;
1128 }
1129 if (!prefixcmp(arg, "--disable=")) {
1130 enable_service(arg + 10, 0);
1131 continue;
1132 }
1133 if (!prefixcmp(arg, "--allow-override=")) {
1134 make_service_overridable(arg + 17, 1);
1135 continue;
1136 }
1137 if (!prefixcmp(arg, "--forbid-override=")) {
1138 make_service_overridable(arg + 18, 0);
1139 continue;
1140 }
1141 if (!strcmp(arg, "--")) {
1142 ok_paths = &argv[i+1];
1143 break;
1144 } else if (arg[0] != '-') {
1145 ok_paths = &argv[i];
1146 break;
1147 }
1148
1149 usage(daemon_usage);
1150 }
1151
1152 if (log_syslog) {
1153 openlog("git-daemon", 0, LOG_DAEMON);
1154 set_die_routine(daemon_die);
1155 }
1156
1157 if (inetd_mode && (group_name || user_name))
1158 die("--user and --group are incompatible with --inetd");
1159
1160 if (inetd_mode && (listen_port || listen_addr))
1161 die("--listen= and --port= are incompatible with --inetd");
1162 else if (listen_port == 0)
1163 listen_port = DEFAULT_GIT_PORT;
1164
1165 if (group_name && !user_name)
1166 die("--group supplied without --user");
1167
1168 if (user_name) {
1169 pass = getpwnam(user_name);
1170 if (!pass)
1171 die("user not found - %s", user_name);
1172
1173 if (!group_name)
1174 gid = pass->pw_gid;
1175 else {
1176 group = getgrnam(group_name);
1177 if (!group)
1178 die("group not found - %s", group_name);
1179
1180 gid = group->gr_gid;
1181 }
1182 }
1183
1184 if (strict_paths && (!ok_paths || !*ok_paths))
1185 die("option --strict-paths requires a whitelist");
1186
1187 if (base_path) {
1188 struct stat st;
1189
1190 if (stat(base_path, &st) || !S_ISDIR(st.st_mode))
1191 die("base-path '%s' does not exist or "
1192 "is not a directory", base_path);
1193 }
1194
1195 if (inetd_mode) {
1196 struct sockaddr_storage ss;
1197 struct sockaddr *peer = (struct sockaddr *)&ss;
1198 socklen_t slen = sizeof(ss);
1199
1200 freopen("/dev/null", "w", stderr);
1201
1202 if (getpeername(0, peer, &slen))
1203 peer = NULL;
1204
1205 return execute(peer);
1206 }
1207
1208 if (detach)
1209 daemonize();
1210 else
1211 sanitize_stdfds();
1212
1213 if (pid_file)
1214 store_pid(pid_file);
1215
1216 return serve(listen_addr, listen_port, pass, gid);
1217 }