5335d212c32a82b10483b10866f361f5c5a5bc85
[git/git.git] / daemon.c
1 #include <signal.h>
2 #include <sys/wait.h>
3 #include <sys/socket.h>
4 #include <sys/time.h>
5 #include <sys/poll.h>
6 #include <netdb.h>
7 #include <netinet/in.h>
8 #include <arpa/inet.h>
9 #include <syslog.h>
10 #include <pwd.h>
11 #include <grp.h>
12 #include <limits.h>
13 #include "pkt-line.h"
14 #include "cache.h"
15 #include "exec_cmd.h"
16 #include "interpolate.h"
17
18 static int log_syslog;
19 static int verbose;
20 static int reuseaddr;
21
22 static const char daemon_usage[] =
23 "git-daemon [--verbose] [--syslog] [--export-all]\n"
24 " [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
25 " [--base-path=path] [--user-path | --user-path=path]\n"
26 " [--interpolated-path=path]\n"
27 " [--reuseaddr] [--detach] [--pid-file=file]\n"
28 " [--[enable|disable|allow-override|forbid-override]=service]\n"
29 " [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
30 " [--user=user [--group=group]]\n"
31 " [directory...]";
32
33 /* List of acceptable pathname prefixes */
34 static char **ok_paths;
35 static int strict_paths;
36
37 /* If this is set, git-daemon-export-ok is not required */
38 static int export_all_trees;
39
40 /* Take all paths relative to this one if non-NULL */
41 static char *base_path;
42 static char *interpolated_path;
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(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 char *path;
190 char *dir;
191
192 dir = itable[INTERP_SLOT_DIR].value;
193
194 if (avoid_alias(dir)) {
195 logerror("'%s': aliased", dir);
196 return NULL;
197 }
198
199 if (*dir == '~') {
200 if (!user_path) {
201 logerror("'%s': User-path not allowed", dir);
202 return NULL;
203 }
204 if (*user_path) {
205 /* Got either "~alice" or "~alice/foo";
206 * rewrite them to "~alice/%s" or
207 * "~alice/%s/foo".
208 */
209 int namlen, restlen = strlen(dir);
210 char *slash = strchr(dir, '/');
211 if (!slash)
212 slash = dir + restlen;
213 namlen = slash - dir;
214 restlen -= namlen;
215 loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
216 snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
217 namlen, dir, user_path, restlen, slash);
218 dir = rpath;
219 }
220 }
221 else if (interpolated_path && saw_extended_args) {
222 if (*dir != '/') {
223 /* Allow only absolute */
224 logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
225 return NULL;
226 }
227
228 interpolate(interp_path, PATH_MAX, interpolated_path,
229 interp_table, ARRAY_SIZE(interp_table));
230 loginfo("Interpolated dir '%s'", interp_path);
231
232 dir = interp_path;
233 }
234 else if (base_path) {
235 if (*dir != '/') {
236 /* Allow only absolute */
237 logerror("'%s': Non-absolute path denied (base-path active)", dir);
238 return NULL;
239 }
240 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
241 dir = rpath;
242 }
243
244 path = enter_repo(dir, strict_paths);
245
246 if (!path) {
247 logerror("'%s': unable to chdir or not a git archive", dir);
248 return NULL;
249 }
250
251 if ( ok_paths && *ok_paths ) {
252 char **pp;
253 int pathlen = strlen(path);
254
255 /* The validation is done on the paths after enter_repo
256 * appends optional {.git,.git/.git} and friends, but
257 * it does not use getcwd(). So if your /pub is
258 * a symlink to /mnt/pub, you can whitelist /pub and
259 * do not have to say /mnt/pub.
260 * Do not say /pub/.
261 */
262 for ( pp = ok_paths ; *pp ; pp++ ) {
263 int len = strlen(*pp);
264 if (len <= pathlen &&
265 !memcmp(*pp, path, len) &&
266 (path[len] == '\0' ||
267 (!strict_paths && path[len] == '/')))
268 return path;
269 }
270 }
271 else {
272 /* be backwards compatible */
273 if (!strict_paths)
274 return path;
275 }
276
277 logerror("'%s': not in whitelist", path);
278 return NULL; /* Fallthrough. Deny by default */
279 }
280
281 typedef int (*daemon_service_fn)(void);
282 struct daemon_service {
283 const char *name;
284 const char *config_name;
285 daemon_service_fn fn;
286 int enabled;
287 int overridable;
288 };
289
290 static struct daemon_service *service_looking_at;
291 static int service_enabled;
292
293 static int git_daemon_config(const char *var, const char *value)
294 {
295 if (!strncmp(var, "daemon.", 7) &&
296 !strcmp(var + 7, service_looking_at->config_name)) {
297 service_enabled = git_config_bool(var, value);
298 return 0;
299 }
300
301 /* we are not interested in parsing any other configuration here */
302 return 0;
303 }
304
305 static int run_service(struct interp *itable, struct daemon_service *service)
306 {
307 const char *path;
308 int enabled = service->enabled;
309
310 loginfo("Request %s for '%s'",
311 service->name,
312 itable[INTERP_SLOT_DIR].value);
313
314 if (!enabled && !service->overridable) {
315 logerror("'%s': service not enabled.", service->name);
316 errno = EACCES;
317 return -1;
318 }
319
320 if (!(path = path_ok(itable)))
321 return -1;
322
323 /*
324 * Security on the cheap.
325 *
326 * We want a readable HEAD, usable "objects" directory, and
327 * a "git-daemon-export-ok" flag that says that the other side
328 * is ok with us doing this.
329 *
330 * path_ok() uses enter_repo() and does whitelist checking.
331 * We only need to make sure the repository is exported.
332 */
333
334 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
335 logerror("'%s': repository not exported.", path);
336 errno = EACCES;
337 return -1;
338 }
339
340 if (service->overridable) {
341 service_looking_at = service;
342 service_enabled = -1;
343 git_config(git_daemon_config);
344 if (0 <= service_enabled)
345 enabled = service_enabled;
346 }
347 if (!enabled) {
348 logerror("'%s': service not enabled for '%s'",
349 service->name, path);
350 errno = EACCES;
351 return -1;
352 }
353
354 /*
355 * We'll ignore SIGTERM from now on, we have a
356 * good client.
357 */
358 signal(SIGTERM, SIG_IGN);
359
360 return service->fn();
361 }
362
363 static int upload_pack(void)
364 {
365 /* Timeout as string */
366 char timeout_buf[64];
367
368 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
369
370 /* git-upload-pack only ever reads stuff, so this is safe */
371 execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
372 return -1;
373 }
374
375 static int upload_archive(void)
376 {
377 execl_git_cmd("upload-archive", ".", NULL);
378 return -1;
379 }
380
381 static struct daemon_service daemon_service[] = {
382 { "upload-archive", "uploadarch", upload_archive, 0, 1 },
383 { "upload-pack", "uploadpack", upload_pack, 1, 1 },
384 };
385
386 static void enable_service(const char *name, int ena) {
387 int i;
388 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
389 if (!strcmp(daemon_service[i].name, name)) {
390 daemon_service[i].enabled = ena;
391 return;
392 }
393 }
394 die("No such service %s", name);
395 }
396
397 static void make_service_overridable(const char *name, int ena) {
398 int i;
399 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
400 if (!strcmp(daemon_service[i].name, name)) {
401 daemon_service[i].overridable = ena;
402 return;
403 }
404 }
405 die("No such service %s", name);
406 }
407
408 /*
409 * Separate the "extra args" information as supplied by the client connection.
410 * Any resulting data is squirrelled away in the given interpolation table.
411 */
412 static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
413 {
414 char *val;
415 int vallen;
416 char *end = extra_args + buflen;
417
418 while (extra_args < end && *extra_args) {
419 saw_extended_args = 1;
420 if (strncasecmp("host=", extra_args, 5) == 0) {
421 val = extra_args + 5;
422 vallen = strlen(val) + 1;
423 if (*val) {
424 /* Split <host>:<port> at colon. */
425 char *host = val;
426 char *port = strrchr(host, ':');
427 if (port) {
428 *port = 0;
429 port++;
430 interp_set_entry(table, INTERP_SLOT_PORT, port);
431 }
432 interp_set_entry(table, INTERP_SLOT_HOST, host);
433 }
434
435 /* On to the next one */
436 extra_args = val + vallen;
437 }
438 }
439 }
440
441 void fill_in_extra_table_entries(struct interp *itable)
442 {
443 char *hp;
444
445 /*
446 * Replace literal host with lowercase-ized hostname.
447 */
448 hp = interp_table[INTERP_SLOT_HOST].value;
449 for ( ; *hp; hp++)
450 *hp = tolower(*hp);
451
452 /*
453 * Locate canonical hostname and its IP address.
454 */
455 #ifndef NO_IPV6
456 {
457 struct addrinfo hints;
458 struct addrinfo *ai, *ai0;
459 int gai;
460 static char addrbuf[HOST_NAME_MAX + 1];
461
462 memset(&hints, 0, sizeof(hints));
463 hints.ai_flags = AI_CANONNAME;
464
465 gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
466 if (!gai) {
467 for (ai = ai0; ai; ai = ai->ai_next) {
468 struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
469
470 inet_ntop(AF_INET, &sin_addr->sin_addr,
471 addrbuf, sizeof(addrbuf));
472 interp_set_entry(interp_table,
473 INTERP_SLOT_CANON_HOST, ai->ai_canonname);
474 interp_set_entry(interp_table,
475 INTERP_SLOT_IP, addrbuf);
476 break;
477 }
478 freeaddrinfo(ai0);
479 }
480 }
481 #else
482 {
483 struct hostent *hent;
484 struct sockaddr_in sa;
485 char **ap;
486 static char addrbuf[HOST_NAME_MAX + 1];
487
488 hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
489
490 ap = hent->h_addr_list;
491 memset(&sa, 0, sizeof sa);
492 sa.sin_family = hent->h_addrtype;
493 sa.sin_port = htons(0);
494 memcpy(&sa.sin_addr, *ap, hent->h_length);
495
496 inet_ntop(hent->h_addrtype, &sa.sin_addr,
497 addrbuf, sizeof(addrbuf));
498
499 interp_set_entry(interp_table, INTERP_SLOT_CANON_HOST, hent->h_name);
500 interp_set_entry(interp_table, INTERP_SLOT_IP, addrbuf);
501 }
502 #endif
503 }
504
505
506 static int execute(struct sockaddr *addr)
507 {
508 static char line[1000];
509 int pktlen, len, i;
510
511 if (addr) {
512 char addrbuf[256] = "";
513 int port = -1;
514
515 if (addr->sa_family == AF_INET) {
516 struct sockaddr_in *sin_addr = (void *) addr;
517 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
518 port = sin_addr->sin_port;
519 #ifndef NO_IPV6
520 } else if (addr && addr->sa_family == AF_INET6) {
521 struct sockaddr_in6 *sin6_addr = (void *) addr;
522
523 char *buf = addrbuf;
524 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
525 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
526 strcat(buf, "]");
527
528 port = sin6_addr->sin6_port;
529 #endif
530 }
531 loginfo("Connection from %s:%d", addrbuf, port);
532 }
533
534 alarm(init_timeout ? init_timeout : timeout);
535 pktlen = packet_read_line(0, line, sizeof(line));
536 alarm(0);
537
538 len = strlen(line);
539 if (pktlen != len)
540 loginfo("Extended attributes (%d bytes) exist <%.*s>",
541 (int) pktlen - len,
542 (int) pktlen - len, line + len + 1);
543 if (len && line[len-1] == '\n')
544 line[--len] = 0;
545
546 /*
547 * Initialize the path interpolation table for this connection.
548 */
549 interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
550 interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
551
552 if (len != pktlen) {
553 parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
554 fill_in_extra_table_entries(interp_table);
555 }
556
557 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
558 struct daemon_service *s = &(daemon_service[i]);
559 int namelen = strlen(s->name);
560 if (!strncmp("git-", line, 4) &&
561 !strncmp(s->name, line + 4, namelen) &&
562 line[namelen + 4] == ' ') {
563 /*
564 * Note: The directory here is probably context sensitive,
565 * and might depend on the actual service being performed.
566 */
567 interp_set_entry(interp_table,
568 INTERP_SLOT_DIR, line + namelen + 5);
569 return run_service(interp_table, s);
570 }
571 }
572
573 logerror("Protocol error: '%s'", line);
574 return -1;
575 }
576
577
578 /*
579 * We count spawned/reaped separately, just to avoid any
580 * races when updating them from signals. The SIGCHLD handler
581 * will only update children_reaped, and the fork logic will
582 * only update children_spawned.
583 *
584 * MAX_CHILDREN should be a power-of-two to make the modulus
585 * operation cheap. It should also be at least twice
586 * the maximum number of connections we will ever allow.
587 */
588 #define MAX_CHILDREN 128
589
590 static int max_connections = 25;
591
592 /* These are updated by the signal handler */
593 static volatile unsigned int children_reaped;
594 static pid_t dead_child[MAX_CHILDREN];
595
596 /* These are updated by the main loop */
597 static unsigned int children_spawned;
598 static unsigned int children_deleted;
599
600 static struct child {
601 pid_t pid;
602 int addrlen;
603 struct sockaddr_storage address;
604 } live_child[MAX_CHILDREN];
605
606 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
607 {
608 live_child[idx].pid = pid;
609 live_child[idx].addrlen = addrlen;
610 memcpy(&live_child[idx].address, addr, addrlen);
611 }
612
613 /*
614 * Walk from "deleted" to "spawned", and remove child "pid".
615 *
616 * We move everything up by one, since the new "deleted" will
617 * be one higher.
618 */
619 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
620 {
621 struct child n;
622
623 deleted %= MAX_CHILDREN;
624 spawned %= MAX_CHILDREN;
625 if (live_child[deleted].pid == pid) {
626 live_child[deleted].pid = -1;
627 return;
628 }
629 n = live_child[deleted];
630 for (;;) {
631 struct child m;
632 deleted = (deleted + 1) % MAX_CHILDREN;
633 if (deleted == spawned)
634 die("could not find dead child %d\n", pid);
635 m = live_child[deleted];
636 live_child[deleted] = n;
637 if (m.pid == pid)
638 return;
639 n = m;
640 }
641 }
642
643 /*
644 * This gets called if the number of connections grows
645 * past "max_connections".
646 *
647 * We _should_ start off by searching for connections
648 * from the same IP, and if there is some address wth
649 * multiple connections, we should kill that first.
650 *
651 * As it is, we just "randomly" kill 25% of the connections,
652 * and our pseudo-random generator sucks too. I have no
653 * shame.
654 *
655 * Really, this is just a place-holder for a _real_ algorithm.
656 */
657 static void kill_some_children(int signo, unsigned start, unsigned stop)
658 {
659 start %= MAX_CHILDREN;
660 stop %= MAX_CHILDREN;
661 while (start != stop) {
662 if (!(start & 3))
663 kill(live_child[start].pid, signo);
664 start = (start + 1) % MAX_CHILDREN;
665 }
666 }
667
668 static void check_max_connections(void)
669 {
670 for (;;) {
671 int active;
672 unsigned spawned, reaped, deleted;
673
674 spawned = children_spawned;
675 reaped = children_reaped;
676 deleted = children_deleted;
677
678 while (deleted < reaped) {
679 pid_t pid = dead_child[deleted % MAX_CHILDREN];
680 remove_child(pid, deleted, spawned);
681 deleted++;
682 }
683 children_deleted = deleted;
684
685 active = spawned - deleted;
686 if (active <= max_connections)
687 break;
688
689 /* Kill some unstarted connections with SIGTERM */
690 kill_some_children(SIGTERM, deleted, spawned);
691 if (active <= max_connections << 1)
692 break;
693
694 /* If the SIGTERM thing isn't helping use SIGKILL */
695 kill_some_children(SIGKILL, deleted, spawned);
696 sleep(1);
697 }
698 }
699
700 static void handle(int incoming, struct sockaddr *addr, int addrlen)
701 {
702 pid_t pid = fork();
703
704 if (pid) {
705 unsigned idx;
706
707 close(incoming);
708 if (pid < 0)
709 return;
710
711 idx = children_spawned % MAX_CHILDREN;
712 children_spawned++;
713 add_child(idx, pid, addr, addrlen);
714
715 check_max_connections();
716 return;
717 }
718
719 dup2(incoming, 0);
720 dup2(incoming, 1);
721 close(incoming);
722
723 exit(execute(addr));
724 }
725
726 static void child_handler(int signo)
727 {
728 for (;;) {
729 int status;
730 pid_t pid = waitpid(-1, &status, WNOHANG);
731
732 if (pid > 0) {
733 unsigned reaped = children_reaped;
734 dead_child[reaped % MAX_CHILDREN] = pid;
735 children_reaped = reaped + 1;
736 /* XXX: Custom logging, since we don't wanna getpid() */
737 if (verbose) {
738 const char *dead = "";
739 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
740 dead = " (with error)";
741 if (log_syslog)
742 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
743 else
744 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
745 }
746 continue;
747 }
748 break;
749 }
750 }
751
752 static int set_reuse_addr(int sockfd)
753 {
754 int on = 1;
755
756 if (!reuseaddr)
757 return 0;
758 return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
759 &on, sizeof(on));
760 }
761
762 #ifndef NO_IPV6
763
764 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
765 {
766 int socknum = 0, *socklist = NULL;
767 int maxfd = -1;
768 char pbuf[NI_MAXSERV];
769 struct addrinfo hints, *ai0, *ai;
770 int gai;
771
772 sprintf(pbuf, "%d", listen_port);
773 memset(&hints, 0, sizeof(hints));
774 hints.ai_family = AF_UNSPEC;
775 hints.ai_socktype = SOCK_STREAM;
776 hints.ai_protocol = IPPROTO_TCP;
777 hints.ai_flags = AI_PASSIVE;
778
779 gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
780 if (gai)
781 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
782
783 for (ai = ai0; ai; ai = ai->ai_next) {
784 int sockfd;
785
786 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
787 if (sockfd < 0)
788 continue;
789 if (sockfd >= FD_SETSIZE) {
790 error("too large socket descriptor.");
791 close(sockfd);
792 continue;
793 }
794
795 #ifdef IPV6_V6ONLY
796 if (ai->ai_family == AF_INET6) {
797 int on = 1;
798 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
799 &on, sizeof(on));
800 /* Note: error is not fatal */
801 }
802 #endif
803
804 if (set_reuse_addr(sockfd)) {
805 close(sockfd);
806 continue;
807 }
808
809 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
810 close(sockfd);
811 continue; /* not fatal */
812 }
813 if (listen(sockfd, 5) < 0) {
814 close(sockfd);
815 continue; /* not fatal */
816 }
817
818 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
819 socklist[socknum++] = sockfd;
820
821 if (maxfd < sockfd)
822 maxfd = sockfd;
823 }
824
825 freeaddrinfo(ai0);
826
827 *socklist_p = socklist;
828 return socknum;
829 }
830
831 #else /* NO_IPV6 */
832
833 static int socksetup(char *lisen_addr, int listen_port, int **socklist_p)
834 {
835 struct sockaddr_in sin;
836 int sockfd;
837
838 memset(&sin, 0, sizeof sin);
839 sin.sin_family = AF_INET;
840 sin.sin_port = htons(listen_port);
841
842 if (listen_addr) {
843 /* Well, host better be an IP address here. */
844 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
845 return 0;
846 } else {
847 sin.sin_addr.s_addr = htonl(INADDR_ANY);
848 }
849
850 sockfd = socket(AF_INET, SOCK_STREAM, 0);
851 if (sockfd < 0)
852 return 0;
853
854 if (set_reuse_addr(sockfd)) {
855 close(sockfd);
856 return 0;
857 }
858
859 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
860 close(sockfd);
861 return 0;
862 }
863
864 if (listen(sockfd, 5) < 0) {
865 close(sockfd);
866 return 0;
867 }
868
869 *socklist_p = xmalloc(sizeof(int));
870 **socklist_p = sockfd;
871 return 1;
872 }
873
874 #endif
875
876 static int service_loop(int socknum, int *socklist)
877 {
878 struct pollfd *pfd;
879 int i;
880
881 pfd = xcalloc(socknum, sizeof(struct pollfd));
882
883 for (i = 0; i < socknum; i++) {
884 pfd[i].fd = socklist[i];
885 pfd[i].events = POLLIN;
886 }
887
888 signal(SIGCHLD, child_handler);
889
890 for (;;) {
891 int i;
892
893 if (poll(pfd, socknum, -1) < 0) {
894 if (errno != EINTR) {
895 error("poll failed, resuming: %s",
896 strerror(errno));
897 sleep(1);
898 }
899 continue;
900 }
901
902 for (i = 0; i < socknum; i++) {
903 if (pfd[i].revents & POLLIN) {
904 struct sockaddr_storage ss;
905 unsigned int sslen = sizeof(ss);
906 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
907 if (incoming < 0) {
908 switch (errno) {
909 case EAGAIN:
910 case EINTR:
911 case ECONNABORTED:
912 continue;
913 default:
914 die("accept returned %s", strerror(errno));
915 }
916 }
917 handle(incoming, (struct sockaddr *)&ss, sslen);
918 }
919 }
920 }
921 }
922
923 /* if any standard file descriptor is missing open it to /dev/null */
924 static void sanitize_stdfds(void)
925 {
926 int fd = open("/dev/null", O_RDWR, 0);
927 while (fd != -1 && fd < 2)
928 fd = dup(fd);
929 if (fd == -1)
930 die("open /dev/null or dup failed: %s", strerror(errno));
931 if (fd > 2)
932 close(fd);
933 }
934
935 static void daemonize(void)
936 {
937 switch (fork()) {
938 case 0:
939 break;
940 case -1:
941 die("fork failed: %s", strerror(errno));
942 default:
943 exit(0);
944 }
945 if (setsid() == -1)
946 die("setsid failed: %s", strerror(errno));
947 close(0);
948 close(1);
949 close(2);
950 sanitize_stdfds();
951 }
952
953 static void store_pid(const char *path)
954 {
955 FILE *f = fopen(path, "w");
956 if (!f)
957 die("cannot open pid file %s: %s", path, strerror(errno));
958 fprintf(f, "%d\n", getpid());
959 fclose(f);
960 }
961
962 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
963 {
964 int socknum, *socklist;
965
966 socknum = socksetup(listen_addr, listen_port, &socklist);
967 if (socknum == 0)
968 die("unable to allocate any listen sockets on host %s port %u",
969 listen_addr, listen_port);
970
971 if (pass && gid &&
972 (initgroups(pass->pw_name, gid) || setgid (gid) ||
973 setuid(pass->pw_uid)))
974 die("cannot drop privileges");
975
976 return service_loop(socknum, socklist);
977 }
978
979 int main(int argc, char **argv)
980 {
981 int listen_port = 0;
982 char *listen_addr = NULL;
983 int inetd_mode = 0;
984 const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
985 int detach = 0;
986 struct passwd *pass = NULL;
987 struct group *group;
988 gid_t gid = 0;
989 int i;
990
991 /* Without this we cannot rely on waitpid() to tell
992 * what happened to our children.
993 */
994 signal(SIGCHLD, SIG_DFL);
995
996 for (i = 1; i < argc; i++) {
997 char *arg = argv[i];
998
999 if (!strncmp(arg, "--listen=", 9)) {
1000 char *p = arg + 9;
1001 char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
1002 while (*p)
1003 *ph++ = tolower(*p++);
1004 *ph = 0;
1005 continue;
1006 }
1007 if (!strncmp(arg, "--port=", 7)) {
1008 char *end;
1009 unsigned long n;
1010 n = strtoul(arg+7, &end, 0);
1011 if (arg[7] && !*end) {
1012 listen_port = n;
1013 continue;
1014 }
1015 }
1016 if (!strcmp(arg, "--inetd")) {
1017 inetd_mode = 1;
1018 log_syslog = 1;
1019 continue;
1020 }
1021 if (!strcmp(arg, "--verbose")) {
1022 verbose = 1;
1023 continue;
1024 }
1025 if (!strcmp(arg, "--syslog")) {
1026 log_syslog = 1;
1027 continue;
1028 }
1029 if (!strcmp(arg, "--export-all")) {
1030 export_all_trees = 1;
1031 continue;
1032 }
1033 if (!strncmp(arg, "--timeout=", 10)) {
1034 timeout = atoi(arg+10);
1035 continue;
1036 }
1037 if (!strncmp(arg, "--init-timeout=", 15)) {
1038 init_timeout = atoi(arg+15);
1039 continue;
1040 }
1041 if (!strcmp(arg, "--strict-paths")) {
1042 strict_paths = 1;
1043 continue;
1044 }
1045 if (!strncmp(arg, "--base-path=", 12)) {
1046 base_path = arg+12;
1047 continue;
1048 }
1049 if (!strncmp(arg, "--interpolated-path=", 20)) {
1050 interpolated_path = arg+20;
1051 continue;
1052 }
1053 if (!strcmp(arg, "--reuseaddr")) {
1054 reuseaddr = 1;
1055 continue;
1056 }
1057 if (!strcmp(arg, "--user-path")) {
1058 user_path = "";
1059 continue;
1060 }
1061 if (!strncmp(arg, "--user-path=", 12)) {
1062 user_path = arg + 12;
1063 continue;
1064 }
1065 if (!strncmp(arg, "--pid-file=", 11)) {
1066 pid_file = arg + 11;
1067 continue;
1068 }
1069 if (!strcmp(arg, "--detach")) {
1070 detach = 1;
1071 log_syslog = 1;
1072 continue;
1073 }
1074 if (!strncmp(arg, "--user=", 7)) {
1075 user_name = arg + 7;
1076 continue;
1077 }
1078 if (!strncmp(arg, "--group=", 8)) {
1079 group_name = arg + 8;
1080 continue;
1081 }
1082 if (!strncmp(arg, "--enable=", 9)) {
1083 enable_service(arg + 9, 1);
1084 continue;
1085 }
1086 if (!strncmp(arg, "--disable=", 10)) {
1087 enable_service(arg + 10, 0);
1088 continue;
1089 }
1090 if (!strncmp(arg, "--allow-override=", 17)) {
1091 make_service_overridable(arg + 17, 1);
1092 continue;
1093 }
1094 if (!strncmp(arg, "--forbid-override=", 18)) {
1095 make_service_overridable(arg + 18, 0);
1096 continue;
1097 }
1098 if (!strcmp(arg, "--")) {
1099 ok_paths = &argv[i+1];
1100 break;
1101 } else if (arg[0] != '-') {
1102 ok_paths = &argv[i];
1103 break;
1104 }
1105
1106 usage(daemon_usage);
1107 }
1108
1109 if (inetd_mode && (group_name || user_name))
1110 die("--user and --group are incompatible with --inetd");
1111
1112 if (inetd_mode && (listen_port || listen_addr))
1113 die("--listen= and --port= are incompatible with --inetd");
1114 else if (listen_port == 0)
1115 listen_port = DEFAULT_GIT_PORT;
1116
1117 if (group_name && !user_name)
1118 die("--group supplied without --user");
1119
1120 if (user_name) {
1121 pass = getpwnam(user_name);
1122 if (!pass)
1123 die("user not found - %s", user_name);
1124
1125 if (!group_name)
1126 gid = pass->pw_gid;
1127 else {
1128 group = getgrnam(group_name);
1129 if (!group)
1130 die("group not found - %s", group_name);
1131
1132 gid = group->gr_gid;
1133 }
1134 }
1135
1136 if (log_syslog) {
1137 openlog("git-daemon", 0, LOG_DAEMON);
1138 set_die_routine(daemon_die);
1139 }
1140
1141 if (strict_paths && (!ok_paths || !*ok_paths))
1142 die("option --strict-paths requires a whitelist");
1143
1144 if (inetd_mode) {
1145 struct sockaddr_storage ss;
1146 struct sockaddr *peer = (struct sockaddr *)&ss;
1147 socklen_t slen = sizeof(ss);
1148
1149 freopen("/dev/null", "w", stderr);
1150
1151 if (getpeername(0, peer, &slen))
1152 peer = NULL;
1153
1154 return execute(peer);
1155 }
1156
1157 if (detach)
1158 daemonize();
1159 else
1160 sanitize_stdfds();
1161
1162 if (pid_file)
1163 store_pid(pid_file);
1164
1165 return serve(listen_addr, listen_port, pass, gid);
1166 }