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