69ea35c22dcff884899a083b678b0a4757e546ad
[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 { "%%", "%"},
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 static void parse_extra_args(char *extra_args, int buflen)
409 {
410 char *val;
411 int vallen;
412 char *end = extra_args + buflen;
413
414 while (extra_args < end && *extra_args) {
415 saw_extended_args = 1;
416 if (strncasecmp("host=", extra_args, 5) == 0) {
417 val = extra_args + 5;
418 vallen = strlen(val) + 1;
419 if (*val) {
420 char *port;
421 char *save = xmalloc(vallen); /* FIXME: Leak */
422
423 interp_table[INTERP_SLOT_HOST].value = save;
424 strlcpy(save, val, vallen);
425 port = strrchr(save, ':');
426 if (port) {
427 *port = 0;
428 port++;
429 interp_table[INTERP_SLOT_PORT].value = port;
430 }
431 }
432 /* On to the next one */
433 extra_args = val + vallen;
434 }
435 }
436 }
437
438 void fill_in_extra_table_entries(struct interp *itable)
439 {
440 char *hp;
441 char *canon_host = NULL;
442 char *ipaddr = NULL;
443
444 /*
445 * Replace literal host with lowercase-ized hostname.
446 */
447 hp = interp_table[INTERP_SLOT_HOST].value;
448 for ( ; *hp; hp++)
449 *hp = tolower(*hp);
450
451 /*
452 * Locate canonical hostname and its IP address.
453 */
454 #ifndef NO_IPV6
455 {
456 struct addrinfo hints;
457 struct addrinfo *ai, *ai0;
458 int gai;
459 static char addrbuf[HOST_NAME_MAX + 1];
460
461 memset(&hints, 0, sizeof(hints));
462 hints.ai_flags = AI_CANONNAME;
463
464 gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
465 if (!gai) {
466 for (ai = ai0; ai; ai = ai->ai_next) {
467 struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
468
469 canon_host = xstrdup(ai->ai_canonname);
470 inet_ntop(AF_INET, &sin_addr->sin_addr,
471 addrbuf, sizeof(addrbuf));
472 ipaddr = addrbuf;
473 break;
474 }
475 freeaddrinfo(ai0);
476 }
477 }
478 #else
479 {
480 struct hostent *hent;
481 struct sockaddr_in sa;
482 char **ap;
483 static char addrbuf[HOST_NAME_MAX + 1];
484
485 hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
486 canon_host = xstrdup(hent->h_name);
487
488 ap = hent->h_addr_list;
489 memset(&sa, 0, sizeof sa);
490 sa.sin_family = hent->h_addrtype;
491 sa.sin_port = htons(0);
492 memcpy(&sa.sin_addr, *ap, hent->h_length);
493
494 inet_ntop(hent->h_addrtype, &sa.sin_addr,
495 addrbuf, sizeof(addrbuf));
496 ipaddr = addrbuf;
497 }
498 #endif
499
500 interp_table[INTERP_SLOT_CANON_HOST].value = canon_host; /* FIXME: Leak */
501 interp_table[INTERP_SLOT_IP].value = xstrdup(ipaddr); /* FIXME: Leak */
502 }
503
504
505 static int execute(struct sockaddr *addr)
506 {
507 static char line[1000];
508 int pktlen, len, i;
509
510 if (addr) {
511 char addrbuf[256] = "";
512 int port = -1;
513
514 if (addr->sa_family == AF_INET) {
515 struct sockaddr_in *sin_addr = (void *) addr;
516 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
517 port = sin_addr->sin_port;
518 #ifndef NO_IPV6
519 } else if (addr && addr->sa_family == AF_INET6) {
520 struct sockaddr_in6 *sin6_addr = (void *) addr;
521
522 char *buf = addrbuf;
523 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
524 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
525 strcat(buf, "]");
526
527 port = sin6_addr->sin6_port;
528 #endif
529 }
530 loginfo("Connection from %s:%d", addrbuf, port);
531 }
532
533 alarm(init_timeout ? init_timeout : timeout);
534 pktlen = packet_read_line(0, line, sizeof(line));
535 alarm(0);
536
537 len = strlen(line);
538 if (pktlen != len)
539 loginfo("Extended attributes (%d bytes) exist <%.*s>",
540 (int) pktlen - len,
541 (int) pktlen - len, line + len + 1);
542 if (len && line[len-1] == '\n')
543 line[--len] = 0;
544
545 if (len != pktlen) {
546 parse_extra_args(line + len + 1, pktlen - len - 1);
547 fill_in_extra_table_entries(interp_table);
548 }
549
550 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
551 struct daemon_service *s = &(daemon_service[i]);
552 int namelen = strlen(s->name);
553 if (!strncmp("git-", line, 4) &&
554 !strncmp(s->name, line + 4, namelen) &&
555 line[namelen + 4] == ' ') {
556 interp_table[INTERP_SLOT_DIR].value = line+namelen+5;
557 return run_service(interp_table, s);
558 }
559 }
560
561 logerror("Protocol error: '%s'", line);
562 return -1;
563 }
564
565
566 /*
567 * We count spawned/reaped separately, just to avoid any
568 * races when updating them from signals. The SIGCHLD handler
569 * will only update children_reaped, and the fork logic will
570 * only update children_spawned.
571 *
572 * MAX_CHILDREN should be a power-of-two to make the modulus
573 * operation cheap. It should also be at least twice
574 * the maximum number of connections we will ever allow.
575 */
576 #define MAX_CHILDREN 128
577
578 static int max_connections = 25;
579
580 /* These are updated by the signal handler */
581 static volatile unsigned int children_reaped;
582 static pid_t dead_child[MAX_CHILDREN];
583
584 /* These are updated by the main loop */
585 static unsigned int children_spawned;
586 static unsigned int children_deleted;
587
588 static struct child {
589 pid_t pid;
590 int addrlen;
591 struct sockaddr_storage address;
592 } live_child[MAX_CHILDREN];
593
594 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
595 {
596 live_child[idx].pid = pid;
597 live_child[idx].addrlen = addrlen;
598 memcpy(&live_child[idx].address, addr, addrlen);
599 }
600
601 /*
602 * Walk from "deleted" to "spawned", and remove child "pid".
603 *
604 * We move everything up by one, since the new "deleted" will
605 * be one higher.
606 */
607 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
608 {
609 struct child n;
610
611 deleted %= MAX_CHILDREN;
612 spawned %= MAX_CHILDREN;
613 if (live_child[deleted].pid == pid) {
614 live_child[deleted].pid = -1;
615 return;
616 }
617 n = live_child[deleted];
618 for (;;) {
619 struct child m;
620 deleted = (deleted + 1) % MAX_CHILDREN;
621 if (deleted == spawned)
622 die("could not find dead child %d\n", pid);
623 m = live_child[deleted];
624 live_child[deleted] = n;
625 if (m.pid == pid)
626 return;
627 n = m;
628 }
629 }
630
631 /*
632 * This gets called if the number of connections grows
633 * past "max_connections".
634 *
635 * We _should_ start off by searching for connections
636 * from the same IP, and if there is some address wth
637 * multiple connections, we should kill that first.
638 *
639 * As it is, we just "randomly" kill 25% of the connections,
640 * and our pseudo-random generator sucks too. I have no
641 * shame.
642 *
643 * Really, this is just a place-holder for a _real_ algorithm.
644 */
645 static void kill_some_children(int signo, unsigned start, unsigned stop)
646 {
647 start %= MAX_CHILDREN;
648 stop %= MAX_CHILDREN;
649 while (start != stop) {
650 if (!(start & 3))
651 kill(live_child[start].pid, signo);
652 start = (start + 1) % MAX_CHILDREN;
653 }
654 }
655
656 static void check_max_connections(void)
657 {
658 for (;;) {
659 int active;
660 unsigned spawned, reaped, deleted;
661
662 spawned = children_spawned;
663 reaped = children_reaped;
664 deleted = children_deleted;
665
666 while (deleted < reaped) {
667 pid_t pid = dead_child[deleted % MAX_CHILDREN];
668 remove_child(pid, deleted, spawned);
669 deleted++;
670 }
671 children_deleted = deleted;
672
673 active = spawned - deleted;
674 if (active <= max_connections)
675 break;
676
677 /* Kill some unstarted connections with SIGTERM */
678 kill_some_children(SIGTERM, deleted, spawned);
679 if (active <= max_connections << 1)
680 break;
681
682 /* If the SIGTERM thing isn't helping use SIGKILL */
683 kill_some_children(SIGKILL, deleted, spawned);
684 sleep(1);
685 }
686 }
687
688 static void handle(int incoming, struct sockaddr *addr, int addrlen)
689 {
690 pid_t pid = fork();
691
692 if (pid) {
693 unsigned idx;
694
695 close(incoming);
696 if (pid < 0)
697 return;
698
699 idx = children_spawned % MAX_CHILDREN;
700 children_spawned++;
701 add_child(idx, pid, addr, addrlen);
702
703 check_max_connections();
704 return;
705 }
706
707 dup2(incoming, 0);
708 dup2(incoming, 1);
709 close(incoming);
710
711 exit(execute(addr));
712 }
713
714 static void child_handler(int signo)
715 {
716 for (;;) {
717 int status;
718 pid_t pid = waitpid(-1, &status, WNOHANG);
719
720 if (pid > 0) {
721 unsigned reaped = children_reaped;
722 dead_child[reaped % MAX_CHILDREN] = pid;
723 children_reaped = reaped + 1;
724 /* XXX: Custom logging, since we don't wanna getpid() */
725 if (verbose) {
726 const char *dead = "";
727 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
728 dead = " (with error)";
729 if (log_syslog)
730 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
731 else
732 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
733 }
734 continue;
735 }
736 break;
737 }
738 }
739
740 static int set_reuse_addr(int sockfd)
741 {
742 int on = 1;
743
744 if (!reuseaddr)
745 return 0;
746 return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
747 &on, sizeof(on));
748 }
749
750 #ifndef NO_IPV6
751
752 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
753 {
754 int socknum = 0, *socklist = NULL;
755 int maxfd = -1;
756 char pbuf[NI_MAXSERV];
757 struct addrinfo hints, *ai0, *ai;
758 int gai;
759
760 sprintf(pbuf, "%d", listen_port);
761 memset(&hints, 0, sizeof(hints));
762 hints.ai_family = AF_UNSPEC;
763 hints.ai_socktype = SOCK_STREAM;
764 hints.ai_protocol = IPPROTO_TCP;
765 hints.ai_flags = AI_PASSIVE;
766
767 gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
768 if (gai)
769 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
770
771 for (ai = ai0; ai; ai = ai->ai_next) {
772 int sockfd;
773
774 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
775 if (sockfd < 0)
776 continue;
777 if (sockfd >= FD_SETSIZE) {
778 error("too large socket descriptor.");
779 close(sockfd);
780 continue;
781 }
782
783 #ifdef IPV6_V6ONLY
784 if (ai->ai_family == AF_INET6) {
785 int on = 1;
786 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
787 &on, sizeof(on));
788 /* Note: error is not fatal */
789 }
790 #endif
791
792 if (set_reuse_addr(sockfd)) {
793 close(sockfd);
794 continue;
795 }
796
797 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
798 close(sockfd);
799 continue; /* not fatal */
800 }
801 if (listen(sockfd, 5) < 0) {
802 close(sockfd);
803 continue; /* not fatal */
804 }
805
806 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
807 socklist[socknum++] = sockfd;
808
809 if (maxfd < sockfd)
810 maxfd = sockfd;
811 }
812
813 freeaddrinfo(ai0);
814
815 *socklist_p = socklist;
816 return socknum;
817 }
818
819 #else /* NO_IPV6 */
820
821 static int socksetup(char *lisen_addr, int listen_port, int **socklist_p)
822 {
823 struct sockaddr_in sin;
824 int sockfd;
825
826 memset(&sin, 0, sizeof sin);
827 sin.sin_family = AF_INET;
828 sin.sin_port = htons(listen_port);
829
830 if (listen_addr) {
831 /* Well, host better be an IP address here. */
832 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
833 return 0;
834 } else {
835 sin.sin_addr.s_addr = htonl(INADDR_ANY);
836 }
837
838 sockfd = socket(AF_INET, SOCK_STREAM, 0);
839 if (sockfd < 0)
840 return 0;
841
842 if (set_reuse_addr(sockfd)) {
843 close(sockfd);
844 return 0;
845 }
846
847 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
848 close(sockfd);
849 return 0;
850 }
851
852 if (listen(sockfd, 5) < 0) {
853 close(sockfd);
854 return 0;
855 }
856
857 *socklist_p = xmalloc(sizeof(int));
858 **socklist_p = sockfd;
859 return 1;
860 }
861
862 #endif
863
864 static int service_loop(int socknum, int *socklist)
865 {
866 struct pollfd *pfd;
867 int i;
868
869 pfd = xcalloc(socknum, sizeof(struct pollfd));
870
871 for (i = 0; i < socknum; i++) {
872 pfd[i].fd = socklist[i];
873 pfd[i].events = POLLIN;
874 }
875
876 signal(SIGCHLD, child_handler);
877
878 for (;;) {
879 int i;
880
881 if (poll(pfd, socknum, -1) < 0) {
882 if (errno != EINTR) {
883 error("poll failed, resuming: %s",
884 strerror(errno));
885 sleep(1);
886 }
887 continue;
888 }
889
890 for (i = 0; i < socknum; i++) {
891 if (pfd[i].revents & POLLIN) {
892 struct sockaddr_storage ss;
893 unsigned int sslen = sizeof(ss);
894 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
895 if (incoming < 0) {
896 switch (errno) {
897 case EAGAIN:
898 case EINTR:
899 case ECONNABORTED:
900 continue;
901 default:
902 die("accept returned %s", strerror(errno));
903 }
904 }
905 handle(incoming, (struct sockaddr *)&ss, sslen);
906 }
907 }
908 }
909 }
910
911 /* if any standard file descriptor is missing open it to /dev/null */
912 static void sanitize_stdfds(void)
913 {
914 int fd = open("/dev/null", O_RDWR, 0);
915 while (fd != -1 && fd < 2)
916 fd = dup(fd);
917 if (fd == -1)
918 die("open /dev/null or dup failed: %s", strerror(errno));
919 if (fd > 2)
920 close(fd);
921 }
922
923 static void daemonize(void)
924 {
925 switch (fork()) {
926 case 0:
927 break;
928 case -1:
929 die("fork failed: %s", strerror(errno));
930 default:
931 exit(0);
932 }
933 if (setsid() == -1)
934 die("setsid failed: %s", strerror(errno));
935 close(0);
936 close(1);
937 close(2);
938 sanitize_stdfds();
939 }
940
941 static void store_pid(const char *path)
942 {
943 FILE *f = fopen(path, "w");
944 if (!f)
945 die("cannot open pid file %s: %s", path, strerror(errno));
946 fprintf(f, "%d\n", getpid());
947 fclose(f);
948 }
949
950 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
951 {
952 int socknum, *socklist;
953
954 socknum = socksetup(listen_addr, listen_port, &socklist);
955 if (socknum == 0)
956 die("unable to allocate any listen sockets on host %s port %u",
957 listen_addr, listen_port);
958
959 if (pass && gid &&
960 (initgroups(pass->pw_name, gid) || setgid (gid) ||
961 setuid(pass->pw_uid)))
962 die("cannot drop privileges");
963
964 return service_loop(socknum, socklist);
965 }
966
967 int main(int argc, char **argv)
968 {
969 int listen_port = 0;
970 char *listen_addr = NULL;
971 int inetd_mode = 0;
972 const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
973 int detach = 0;
974 struct passwd *pass = NULL;
975 struct group *group;
976 gid_t gid = 0;
977 int i;
978
979 /* Without this we cannot rely on waitpid() to tell
980 * what happened to our children.
981 */
982 signal(SIGCHLD, SIG_DFL);
983
984 for (i = 1; i < argc; i++) {
985 char *arg = argv[i];
986
987 if (!strncmp(arg, "--listen=", 9)) {
988 char *p = arg + 9;
989 char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
990 while (*p)
991 *ph++ = tolower(*p++);
992 *ph = 0;
993 continue;
994 }
995 if (!strncmp(arg, "--port=", 7)) {
996 char *end;
997 unsigned long n;
998 n = strtoul(arg+7, &end, 0);
999 if (arg[7] && !*end) {
1000 listen_port = n;
1001 continue;
1002 }
1003 }
1004 if (!strcmp(arg, "--inetd")) {
1005 inetd_mode = 1;
1006 log_syslog = 1;
1007 continue;
1008 }
1009 if (!strcmp(arg, "--verbose")) {
1010 verbose = 1;
1011 continue;
1012 }
1013 if (!strcmp(arg, "--syslog")) {
1014 log_syslog = 1;
1015 continue;
1016 }
1017 if (!strcmp(arg, "--export-all")) {
1018 export_all_trees = 1;
1019 continue;
1020 }
1021 if (!strncmp(arg, "--timeout=", 10)) {
1022 timeout = atoi(arg+10);
1023 continue;
1024 }
1025 if (!strncmp(arg, "--init-timeout=", 15)) {
1026 init_timeout = atoi(arg+15);
1027 continue;
1028 }
1029 if (!strcmp(arg, "--strict-paths")) {
1030 strict_paths = 1;
1031 continue;
1032 }
1033 if (!strncmp(arg, "--base-path=", 12)) {
1034 base_path = arg+12;
1035 continue;
1036 }
1037 if (!strncmp(arg, "--interpolated-path=", 20)) {
1038 interpolated_path = arg+20;
1039 continue;
1040 }
1041 if (!strcmp(arg, "--reuseaddr")) {
1042 reuseaddr = 1;
1043 continue;
1044 }
1045 if (!strcmp(arg, "--user-path")) {
1046 user_path = "";
1047 continue;
1048 }
1049 if (!strncmp(arg, "--user-path=", 12)) {
1050 user_path = arg + 12;
1051 continue;
1052 }
1053 if (!strncmp(arg, "--pid-file=", 11)) {
1054 pid_file = arg + 11;
1055 continue;
1056 }
1057 if (!strcmp(arg, "--detach")) {
1058 detach = 1;
1059 log_syslog = 1;
1060 continue;
1061 }
1062 if (!strncmp(arg, "--user=", 7)) {
1063 user_name = arg + 7;
1064 continue;
1065 }
1066 if (!strncmp(arg, "--group=", 8)) {
1067 group_name = arg + 8;
1068 continue;
1069 }
1070 if (!strncmp(arg, "--enable=", 9)) {
1071 enable_service(arg + 9, 1);
1072 continue;
1073 }
1074 if (!strncmp(arg, "--disable=", 10)) {
1075 enable_service(arg + 10, 0);
1076 continue;
1077 }
1078 if (!strncmp(arg, "--allow-override=", 17)) {
1079 make_service_overridable(arg + 17, 1);
1080 continue;
1081 }
1082 if (!strncmp(arg, "--forbid-override=", 18)) {
1083 make_service_overridable(arg + 18, 0);
1084 continue;
1085 }
1086 if (!strcmp(arg, "--")) {
1087 ok_paths = &argv[i+1];
1088 break;
1089 } else if (arg[0] != '-') {
1090 ok_paths = &argv[i];
1091 break;
1092 }
1093
1094 usage(daemon_usage);
1095 }
1096
1097 if (inetd_mode && (group_name || user_name))
1098 die("--user and --group are incompatible with --inetd");
1099
1100 if (inetd_mode && (listen_port || listen_addr))
1101 die("--listen= and --port= are incompatible with --inetd");
1102 else if (listen_port == 0)
1103 listen_port = DEFAULT_GIT_PORT;
1104
1105 if (group_name && !user_name)
1106 die("--group supplied without --user");
1107
1108 if (user_name) {
1109 pass = getpwnam(user_name);
1110 if (!pass)
1111 die("user not found - %s", user_name);
1112
1113 if (!group_name)
1114 gid = pass->pw_gid;
1115 else {
1116 group = getgrnam(group_name);
1117 if (!group)
1118 die("group not found - %s", group_name);
1119
1120 gid = group->gr_gid;
1121 }
1122 }
1123
1124 if (log_syslog) {
1125 openlog("git-daemon", 0, LOG_DAEMON);
1126 set_die_routine(daemon_die);
1127 }
1128
1129 if (strict_paths && (!ok_paths || !*ok_paths))
1130 die("option --strict-paths requires a whitelist");
1131
1132 if (inetd_mode) {
1133 struct sockaddr_storage ss;
1134 struct sockaddr *peer = (struct sockaddr *)&ss;
1135 socklen_t slen = sizeof(ss);
1136
1137 freopen("/dev/null", "w", stderr);
1138
1139 if (getpeername(0, peer, &slen))
1140 peer = NULL;
1141
1142 return execute(peer);
1143 }
1144
1145 if (detach)
1146 daemonize();
1147 else
1148 sanitize_stdfds();
1149
1150 if (pid_file)
1151 store_pid(pid_file);
1152
1153 return serve(listen_addr, listen_port, pass, gid);
1154 }