Merge branch 'jn/no-g-plus-s-on-bsd'
[git] / daemon.c
1 #include "cache.h"
2 #include "pkt-line.h"
3 #include "exec_cmd.h"
4 #include "run-command.h"
5 #include "strbuf.h"
6 #include "string-list.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 #ifdef NO_INITGROUPS
17 #define initgroups(x, y) (0) /* nothing */
18 #endif
19
20 static int log_syslog;
21 static int verbose;
22 static int reuseaddr;
23
24 static const char daemon_usage[] =
25 "git daemon [--verbose] [--syslog] [--export-all]\n"
26 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
27 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
28 "           [--user-path | --user-path=<path>]\n"
29 "           [--interpolated-path=<path>]\n"
30 "           [--reuseaddr] [--pid-file=<file>]\n"
31 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
32 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
33 "                      [--detach] [--user=<user> [--group=<group>]]\n"
34 "           [<directory>...]";
35
36 /* List of acceptable pathname prefixes */
37 static char **ok_paths;
38 static int strict_paths;
39
40 /* If this is set, git-daemon-export-ok is not required */
41 static int export_all_trees;
42
43 /* Take all paths relative to this one if non-NULL */
44 static char *base_path;
45 static char *interpolated_path;
46 static int base_path_relaxed;
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 static char *hostname;
62 static char *canon_hostname;
63 static char *ip_address;
64 static char *tcp_port;
65
66 static void logreport(int priority, const char *err, va_list params)
67 {
68         if (log_syslog) {
69                 char buf[1024];
70                 vsnprintf(buf, sizeof(buf), err, params);
71                 syslog(priority, "%s", buf);
72         } else {
73                 /*
74                  * Since stderr is set to buffered mode, the
75                  * logging of different processes will not overlap
76                  * unless they overflow the (rather big) buffers.
77                  */
78                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
79                 vfprintf(stderr, err, params);
80                 fputc('\n', stderr);
81                 fflush(stderr);
82         }
83 }
84
85 __attribute__((format (printf, 1, 2)))
86 static void logerror(const char *err, ...)
87 {
88         va_list params;
89         va_start(params, err);
90         logreport(LOG_ERR, err, params);
91         va_end(params);
92 }
93
94 __attribute__((format (printf, 1, 2)))
95 static void loginfo(const char *err, ...)
96 {
97         va_list params;
98         if (!verbose)
99                 return;
100         va_start(params, err);
101         logreport(LOG_INFO, err, params);
102         va_end(params);
103 }
104
105 static void NORETURN daemon_die(const char *err, va_list params)
106 {
107         logreport(LOG_ERR, err, params);
108         exit(1);
109 }
110
111 static char *path_ok(char *directory)
112 {
113         static char rpath[PATH_MAX];
114         static char interp_path[PATH_MAX];
115         char *path;
116         char *dir;
117
118         dir = directory;
119
120         if (daemon_avoid_alias(dir)) {
121                 logerror("'%s': aliased", dir);
122                 return NULL;
123         }
124
125         if (*dir == '~') {
126                 if (!user_path) {
127                         logerror("'%s': User-path not allowed", dir);
128                         return NULL;
129                 }
130                 if (*user_path) {
131                         /* Got either "~alice" or "~alice/foo";
132                          * rewrite them to "~alice/%s" or
133                          * "~alice/%s/foo".
134                          */
135                         int namlen, restlen = strlen(dir);
136                         char *slash = strchr(dir, '/');
137                         if (!slash)
138                                 slash = dir + restlen;
139                         namlen = slash - dir;
140                         restlen -= namlen;
141                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
142                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
143                                  namlen, dir, user_path, restlen, slash);
144                         dir = rpath;
145                 }
146         }
147         else if (interpolated_path && saw_extended_args) {
148                 struct strbuf expanded_path = STRBUF_INIT;
149                 struct strbuf_expand_dict_entry dict[6];
150
151                 dict[0].placeholder = "H"; dict[0].value = hostname;
152                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
153                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
154                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
155                 dict[4].placeholder = "D"; dict[4].value = directory;
156                 dict[5].placeholder = NULL; dict[5].value = NULL;
157                 if (*dir != '/') {
158                         /* Allow only absolute */
159                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
160                         return NULL;
161                 }
162
163                 strbuf_expand(&expanded_path, interpolated_path,
164                                 strbuf_expand_dict_cb, &dict);
165                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
166                 strbuf_release(&expanded_path);
167                 loginfo("Interpolated dir '%s'", interp_path);
168
169                 dir = interp_path;
170         }
171         else if (base_path) {
172                 if (*dir != '/') {
173                         /* Allow only absolute */
174                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
175                         return NULL;
176                 }
177                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
178                 dir = rpath;
179         }
180
181         path = enter_repo(dir, strict_paths);
182         if (!path && base_path && base_path_relaxed) {
183                 /*
184                  * if we fail and base_path_relaxed is enabled, try without
185                  * prefixing the base path
186                  */
187                 dir = directory;
188                 path = enter_repo(dir, strict_paths);
189         }
190
191         if (!path) {
192                 logerror("'%s' does not appear to be a git repository", dir);
193                 return NULL;
194         }
195
196         if ( ok_paths && *ok_paths ) {
197                 char **pp;
198                 int pathlen = strlen(path);
199
200                 /* The validation is done on the paths after enter_repo
201                  * appends optional {.git,.git/.git} and friends, but
202                  * it does not use getcwd().  So if your /pub is
203                  * a symlink to /mnt/pub, you can whitelist /pub and
204                  * do not have to say /mnt/pub.
205                  * Do not say /pub/.
206                  */
207                 for ( pp = ok_paths ; *pp ; pp++ ) {
208                         int len = strlen(*pp);
209                         if (len <= pathlen &&
210                             !memcmp(*pp, path, len) &&
211                             (path[len] == '\0' ||
212                              (!strict_paths && path[len] == '/')))
213                                 return path;
214                 }
215         }
216         else {
217                 /* be backwards compatible */
218                 if (!strict_paths)
219                         return path;
220         }
221
222         logerror("'%s': not in whitelist", path);
223         return NULL;            /* Fallthrough. Deny by default */
224 }
225
226 typedef int (*daemon_service_fn)(void);
227 struct daemon_service {
228         const char *name;
229         const char *config_name;
230         daemon_service_fn fn;
231         int enabled;
232         int overridable;
233 };
234
235 static struct daemon_service *service_looking_at;
236 static int service_enabled;
237
238 static int git_daemon_config(const char *var, const char *value, void *cb)
239 {
240         if (!prefixcmp(var, "daemon.") &&
241             !strcmp(var + 7, service_looking_at->config_name)) {
242                 service_enabled = git_config_bool(var, value);
243                 return 0;
244         }
245
246         /* we are not interested in parsing any other configuration here */
247         return 0;
248 }
249
250 static int run_service(char *dir, struct daemon_service *service)
251 {
252         const char *path;
253         int enabled = service->enabled;
254
255         loginfo("Request %s for '%s'", service->name, dir);
256
257         if (!enabled && !service->overridable) {
258                 logerror("'%s': service not enabled.", service->name);
259                 errno = EACCES;
260                 goto failed;
261         }
262
263         if (!(path = path_ok(dir)))
264                 goto failed;
265
266         /*
267          * Security on the cheap.
268          *
269          * We want a readable HEAD, usable "objects" directory, and
270          * a "git-daemon-export-ok" flag that says that the other side
271          * is ok with us doing this.
272          *
273          * path_ok() uses enter_repo() and does whitelist checking.
274          * We only need to make sure the repository is exported.
275          */
276
277         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
278                 logerror("'%s': repository not exported.", path);
279                 errno = EACCES;
280                 goto failed;
281         }
282
283         if (service->overridable) {
284                 service_looking_at = service;
285                 service_enabled = -1;
286                 git_config(git_daemon_config, NULL);
287                 if (0 <= service_enabled)
288                         enabled = service_enabled;
289         }
290         if (!enabled) {
291                 logerror("'%s': service not enabled for '%s'",
292                          service->name, path);
293                 errno = EACCES;
294                 goto failed;
295         }
296
297         /*
298          * We'll ignore SIGTERM from now on, we have a
299          * good client.
300          */
301         signal(SIGTERM, SIG_IGN);
302
303         return service->fn();
304
305 failed:
306         packet_write(1, "ERR %s: access denied", dir);
307         return -1;
308 }
309
310 static void copy_to_log(int fd)
311 {
312         struct strbuf line = STRBUF_INIT;
313         FILE *fp;
314
315         fp = fdopen(fd, "r");
316         if (fp == NULL) {
317                 logerror("fdopen of error channel failed");
318                 close(fd);
319                 return;
320         }
321
322         while (strbuf_getline(&line, fp, '\n') != EOF) {
323                 logerror("%s", line.buf);
324                 strbuf_setlen(&line, 0);
325         }
326
327         strbuf_release(&line);
328         fclose(fp);
329 }
330
331 static int run_service_command(const char **argv)
332 {
333         struct child_process cld;
334
335         memset(&cld, 0, sizeof(cld));
336         cld.argv = argv;
337         cld.git_cmd = 1;
338         cld.err = -1;
339         if (start_command(&cld))
340                 return -1;
341
342         close(0);
343         close(1);
344
345         copy_to_log(cld.err);
346
347         return finish_command(&cld);
348 }
349
350 static int upload_pack(void)
351 {
352         /* Timeout as string */
353         char timeout_buf[64];
354         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
355
356         argv[2] = timeout_buf;
357
358         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
359         return run_service_command(argv);
360 }
361
362 static int upload_archive(void)
363 {
364         static const char *argv[] = { "upload-archive", ".", NULL };
365         return run_service_command(argv);
366 }
367
368 static int receive_pack(void)
369 {
370         static const char *argv[] = { "receive-pack", ".", NULL };
371         return run_service_command(argv);
372 }
373
374 static struct daemon_service daemon_service[] = {
375         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
376         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
377         { "receive-pack", "receivepack", receive_pack, 0, 1 },
378 };
379
380 static void enable_service(const char *name, int ena)
381 {
382         int i;
383         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
384                 if (!strcmp(daemon_service[i].name, name)) {
385                         daemon_service[i].enabled = ena;
386                         return;
387                 }
388         }
389         die("No such service %s", name);
390 }
391
392 static void make_service_overridable(const char *name, int ena)
393 {
394         int i;
395         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
396                 if (!strcmp(daemon_service[i].name, name)) {
397                         daemon_service[i].overridable = ena;
398                         return;
399                 }
400         }
401         die("No such service %s", name);
402 }
403
404 static char *xstrdup_tolower(const char *str)
405 {
406         char *p, *dup = xstrdup(str);
407         for (p = dup; *p; p++)
408                 *p = tolower(*p);
409         return dup;
410 }
411
412 static void parse_host_and_port(char *hostport, char **host,
413         char **port)
414 {
415         if (*hostport == '[') {
416                 char *end;
417
418                 end = strchr(hostport, ']');
419                 if (!end)
420                         die("Invalid request ('[' without ']')");
421                 *end = '\0';
422                 *host = hostport + 1;
423                 if (!end[1])
424                         *port = NULL;
425                 else if (end[1] == ':')
426                         *port = end + 2;
427                 else
428                         die("Garbage after end of host part");
429         } else {
430                 *host = hostport;
431                 *port = strrchr(hostport, ':');
432                 if (*port) {
433                         **port = '\0';
434                         ++*port;
435                 }
436         }
437 }
438
439 /*
440  * Read the host as supplied by the client connection.
441  */
442 static void parse_host_arg(char *extra_args, int buflen)
443 {
444         char *val;
445         int vallen;
446         char *end = extra_args + buflen;
447
448         if (extra_args < end && *extra_args) {
449                 saw_extended_args = 1;
450                 if (strncasecmp("host=", extra_args, 5) == 0) {
451                         val = extra_args + 5;
452                         vallen = strlen(val) + 1;
453                         if (*val) {
454                                 /* Split <host>:<port> at colon. */
455                                 char *host;
456                                 char *port;
457                                 parse_host_and_port(val, &host, &port);
458                                 if (port) {
459                                         free(tcp_port);
460                                         tcp_port = xstrdup(port);
461                                 }
462                                 free(hostname);
463                                 hostname = xstrdup_tolower(host);
464                         }
465
466                         /* On to the next one */
467                         extra_args = val + vallen;
468                 }
469                 if (extra_args < end && *extra_args)
470                         die("Invalid request");
471         }
472
473         /*
474          * Locate canonical hostname and its IP address.
475          */
476         if (hostname) {
477 #ifndef NO_IPV6
478                 struct addrinfo hints;
479                 struct addrinfo *ai;
480                 int gai;
481                 static char addrbuf[HOST_NAME_MAX + 1];
482
483                 memset(&hints, 0, sizeof(hints));
484                 hints.ai_flags = AI_CANONNAME;
485
486                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
487                 if (!gai) {
488                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
489
490                         inet_ntop(AF_INET, &sin_addr->sin_addr,
491                                   addrbuf, sizeof(addrbuf));
492                         free(ip_address);
493                         ip_address = xstrdup(addrbuf);
494
495                         free(canon_hostname);
496                         canon_hostname = xstrdup(ai->ai_canonname ?
497                                                  ai->ai_canonname : ip_address);
498
499                         freeaddrinfo(ai);
500                 }
501 #else
502                 struct hostent *hent;
503                 struct sockaddr_in sa;
504                 char **ap;
505                 static char addrbuf[HOST_NAME_MAX + 1];
506
507                 hent = gethostbyname(hostname);
508
509                 ap = hent->h_addr_list;
510                 memset(&sa, 0, sizeof sa);
511                 sa.sin_family = hent->h_addrtype;
512                 sa.sin_port = htons(0);
513                 memcpy(&sa.sin_addr, *ap, hent->h_length);
514
515                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
516                           addrbuf, sizeof(addrbuf));
517
518                 free(canon_hostname);
519                 canon_hostname = xstrdup(hent->h_name);
520                 free(ip_address);
521                 ip_address = xstrdup(addrbuf);
522 #endif
523         }
524 }
525
526
527 static int execute(void)
528 {
529         static char line[1000];
530         int pktlen, len, i;
531         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
532
533         if (addr)
534                 loginfo("Connection from %s:%s", addr, port);
535
536         alarm(init_timeout ? init_timeout : timeout);
537         pktlen = packet_read_line(0, line, sizeof(line));
538         alarm(0);
539
540         len = strlen(line);
541         if (pktlen != len)
542                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
543                         (int) pktlen - len,
544                         (int) pktlen - len, line + len + 1);
545         if (len && line[len-1] == '\n') {
546                 line[--len] = 0;
547                 pktlen--;
548         }
549
550         free(hostname);
551         free(canon_hostname);
552         free(ip_address);
553         free(tcp_port);
554         hostname = canon_hostname = ip_address = tcp_port = NULL;
555
556         if (len != pktlen)
557                 parse_host_arg(line + len + 1, pktlen - len - 1);
558
559         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
560                 struct daemon_service *s = &(daemon_service[i]);
561                 int namelen = strlen(s->name);
562                 if (!prefixcmp(line, "git-") &&
563                     !strncmp(s->name, line + 4, namelen) &&
564                     line[namelen + 4] == ' ') {
565                         /*
566                          * Note: The directory here is probably context sensitive,
567                          * and might depend on the actual service being performed.
568                          */
569                         return run_service(line + namelen + 5, s);
570                 }
571         }
572
573         logerror("Protocol error: '%s'", line);
574         return -1;
575 }
576
577 static int addrcmp(const struct sockaddr_storage *s1,
578     const struct sockaddr_storage *s2)
579 {
580         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
581         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
582
583         if (sa1->sa_family != sa2->sa_family)
584                 return sa1->sa_family - sa2->sa_family;
585         if (sa1->sa_family == AF_INET)
586                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
587                     &((struct sockaddr_in *)s2)->sin_addr,
588                     sizeof(struct in_addr));
589 #ifndef NO_IPV6
590         if (sa1->sa_family == AF_INET6)
591                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
592                     &((struct sockaddr_in6 *)s2)->sin6_addr,
593                     sizeof(struct in6_addr));
594 #endif
595         return 0;
596 }
597
598 static int max_connections = 32;
599
600 static unsigned int live_children;
601
602 static struct child {
603         struct child *next;
604         struct child_process cld;
605         struct sockaddr_storage address;
606 } *firstborn;
607
608 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
609 {
610         struct child *newborn, **cradle;
611
612         newborn = xcalloc(1, sizeof(*newborn));
613         live_children++;
614         memcpy(&newborn->cld, cld, sizeof(*cld));
615         memcpy(&newborn->address, addr, addrlen);
616         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
617                 if (!addrcmp(&(*cradle)->address, &newborn->address))
618                         break;
619         newborn->next = *cradle;
620         *cradle = newborn;
621 }
622
623 /*
624  * This gets called if the number of connections grows
625  * past "max_connections".
626  *
627  * We kill the newest connection from a duplicate IP.
628  */
629 static void kill_some_child(void)
630 {
631         const struct child *blanket, *next;
632
633         if (!(blanket = firstborn))
634                 return;
635
636         for (; (next = blanket->next); blanket = next)
637                 if (!addrcmp(&blanket->address, &next->address)) {
638                         kill(blanket->cld.pid, SIGTERM);
639                         break;
640                 }
641 }
642
643 static void check_dead_children(void)
644 {
645         int status;
646         pid_t pid;
647
648         struct child **cradle, *blanket;
649         for (cradle = &firstborn; (blanket = *cradle);)
650                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
651                         const char *dead = "";
652                         if (status)
653                                 dead = " (with error)";
654                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
655
656                         /* remove the child */
657                         *cradle = blanket->next;
658                         live_children--;
659                         free(blanket);
660                 } else
661                         cradle = &blanket->next;
662 }
663
664 static char **cld_argv;
665 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
666 {
667         struct child_process cld = { NULL };
668         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
669         char *env[] = { addrbuf, portbuf, NULL };
670
671         if (max_connections && live_children >= max_connections) {
672                 kill_some_child();
673                 sleep(1);  /* give it some time to die */
674                 check_dead_children();
675                 if (live_children >= max_connections) {
676                         close(incoming);
677                         logerror("Too many children, dropping connection");
678                         return;
679                 }
680         }
681
682         if (addr->sa_family == AF_INET) {
683                 struct sockaddr_in *sin_addr = (void *) addr;
684                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
685                     sizeof(addrbuf) - 12);
686                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
687                     ntohs(sin_addr->sin_port));
688 #ifndef NO_IPV6
689         } else if (addr && addr->sa_family == AF_INET6) {
690                 struct sockaddr_in6 *sin6_addr = (void *) addr;
691
692                 char *buf = addrbuf + 12;
693                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
694                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
695                     sizeof(addrbuf) - 13);
696                 strcat(buf, "]");
697
698                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
699                     ntohs(sin6_addr->sin6_port));
700 #endif
701         }
702
703         cld.env = (const char **)env;
704         cld.argv = (const char **)cld_argv;
705         cld.in = incoming;
706         cld.out = dup(incoming);
707
708         if (start_command(&cld))
709                 logerror("unable to fork");
710         else
711                 add_child(&cld, addr, addrlen);
712         close(incoming);
713 }
714
715 static void child_handler(int signo)
716 {
717         /*
718          * Otherwise empty handler because systemcalls will get interrupted
719          * upon signal receipt
720          * SysV needs the handler to be rearmed
721          */
722         signal(SIGCHLD, child_handler);
723 }
724
725 static int set_reuse_addr(int sockfd)
726 {
727         int on = 1;
728
729         if (!reuseaddr)
730                 return 0;
731         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
732                           &on, sizeof(on));
733 }
734
735 struct socketlist {
736         int *list;
737         size_t nr;
738         size_t alloc;
739 };
740
741 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
742 {
743 #ifdef NO_IPV6
744         static char ip[INET_ADDRSTRLEN];
745 #else
746         static char ip[INET6_ADDRSTRLEN];
747 #endif
748
749         switch (family) {
750 #ifndef NO_IPV6
751         case AF_INET6:
752                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
753                 break;
754 #endif
755         case AF_INET:
756                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
757                 break;
758         default:
759                 strcpy(ip, "<unknown>");
760         }
761         return ip;
762 }
763
764 #ifndef NO_IPV6
765
766 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
767 {
768         int socknum = 0;
769         int maxfd = -1;
770         char pbuf[NI_MAXSERV];
771         struct addrinfo hints, *ai0, *ai;
772         int gai;
773         long flags;
774
775         sprintf(pbuf, "%d", listen_port);
776         memset(&hints, 0, sizeof(hints));
777         hints.ai_family = AF_UNSPEC;
778         hints.ai_socktype = SOCK_STREAM;
779         hints.ai_protocol = IPPROTO_TCP;
780         hints.ai_flags = AI_PASSIVE;
781
782         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
783         if (gai) {
784                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
785                 return 0;
786         }
787
788         for (ai = ai0; ai; ai = ai->ai_next) {
789                 int sockfd;
790
791                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
792                 if (sockfd < 0)
793                         continue;
794                 if (sockfd >= FD_SETSIZE) {
795                         logerror("Socket descriptor too large");
796                         close(sockfd);
797                         continue;
798                 }
799
800 #ifdef IPV6_V6ONLY
801                 if (ai->ai_family == AF_INET6) {
802                         int on = 1;
803                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
804                                    &on, sizeof(on));
805                         /* Note: error is not fatal */
806                 }
807 #endif
808
809                 if (set_reuse_addr(sockfd)) {
810                         logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
811                         close(sockfd);
812                         continue;
813                 }
814
815                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
816                         logerror("Could not bind to %s: %s",
817                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
818                                  strerror(errno));
819                         close(sockfd);
820                         continue;       /* not fatal */
821                 }
822                 if (listen(sockfd, 5) < 0) {
823                         logerror("Could not listen to %s: %s",
824                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
825                                  strerror(errno));
826                         close(sockfd);
827                         continue;       /* not fatal */
828                 }
829
830                 flags = fcntl(sockfd, F_GETFD, 0);
831                 if (flags >= 0)
832                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
833
834                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
835                 socklist->list[socklist->nr++] = sockfd;
836                 socknum++;
837
838                 if (maxfd < sockfd)
839                         maxfd = sockfd;
840         }
841
842         freeaddrinfo(ai0);
843
844         return socknum;
845 }
846
847 #else /* NO_IPV6 */
848
849 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
850 {
851         struct sockaddr_in sin;
852         int sockfd;
853         long flags;
854
855         memset(&sin, 0, sizeof sin);
856         sin.sin_family = AF_INET;
857         sin.sin_port = htons(listen_port);
858
859         if (listen_addr) {
860                 /* Well, host better be an IP address here. */
861                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
862                         return 0;
863         } else {
864                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
865         }
866
867         sockfd = socket(AF_INET, SOCK_STREAM, 0);
868         if (sockfd < 0)
869                 return 0;
870
871         if (set_reuse_addr(sockfd)) {
872                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
873                 close(sockfd);
874                 return 0;
875         }
876
877         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
878                 logerror("Could not listen to %s: %s",
879                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
880                          strerror(errno));
881                 close(sockfd);
882                 return 0;
883         }
884
885         if (listen(sockfd, 5) < 0) {
886                 logerror("Could not listen to %s: %s",
887                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
888                          strerror(errno));
889                 close(sockfd);
890                 return 0;
891         }
892
893         flags = fcntl(sockfd, F_GETFD, 0);
894         if (flags >= 0)
895                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
896
897         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
898         socklist->list[socklist->nr++] = sockfd;
899         return 1;
900 }
901
902 #endif
903
904 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
905 {
906         if (!listen_addr->nr)
907                 setup_named_sock(NULL, listen_port, socklist);
908         else {
909                 int i, socknum;
910                 for (i = 0; i < listen_addr->nr; i++) {
911                         socknum = setup_named_sock(listen_addr->items[i].string,
912                                                    listen_port, socklist);
913
914                         if (socknum == 0)
915                                 logerror("unable to allocate any listen sockets for host %s on port %u",
916                                          listen_addr->items[i].string, listen_port);
917                 }
918         }
919 }
920
921 static int service_loop(struct socketlist *socklist)
922 {
923         struct pollfd *pfd;
924         int i;
925
926         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
927
928         for (i = 0; i < socklist->nr; i++) {
929                 pfd[i].fd = socklist->list[i];
930                 pfd[i].events = POLLIN;
931         }
932
933         signal(SIGCHLD, child_handler);
934
935         for (;;) {
936                 int i;
937
938                 check_dead_children();
939
940                 if (poll(pfd, socklist->nr, -1) < 0) {
941                         if (errno != EINTR) {
942                                 logerror("Poll failed, resuming: %s",
943                                       strerror(errno));
944                                 sleep(1);
945                         }
946                         continue;
947                 }
948
949                 for (i = 0; i < socklist->nr; i++) {
950                         if (pfd[i].revents & POLLIN) {
951                                 union {
952                                         struct sockaddr sa;
953                                         struct sockaddr_in sai;
954 #ifndef NO_IPV6
955                                         struct sockaddr_in6 sai6;
956 #endif
957                                 } ss;
958                                 socklen_t sslen = sizeof(ss);
959                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
960                                 if (incoming < 0) {
961                                         switch (errno) {
962                                         case EAGAIN:
963                                         case EINTR:
964                                         case ECONNABORTED:
965                                                 continue;
966                                         default:
967                                                 die_errno("accept returned");
968                                         }
969                                 }
970                                 handle(incoming, &ss.sa, sslen);
971                         }
972                 }
973         }
974 }
975
976 /* if any standard file descriptor is missing open it to /dev/null */
977 static void sanitize_stdfds(void)
978 {
979         int fd = open("/dev/null", O_RDWR, 0);
980         while (fd != -1 && fd < 2)
981                 fd = dup(fd);
982         if (fd == -1)
983                 die_errno("open /dev/null or dup failed");
984         if (fd > 2)
985                 close(fd);
986 }
987
988 #ifdef NO_POSIX_GOODIES
989
990 struct credentials;
991
992 static void drop_privileges(struct credentials *cred)
993 {
994         /* nothing */
995 }
996
997 static void daemonize(void)
998 {
999         die("--detach not supported on this platform");
1000 }
1001
1002 static struct credentials *prepare_credentials(const char *user_name,
1003     const char *group_name)
1004 {
1005         die("--user not supported on this platform");
1006 }
1007
1008 #else
1009
1010 struct credentials {
1011         struct passwd *pass;
1012         gid_t gid;
1013 };
1014
1015 static void drop_privileges(struct credentials *cred)
1016 {
1017         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1018             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1019                 die("cannot drop privileges");
1020 }
1021
1022 static struct credentials *prepare_credentials(const char *user_name,
1023     const char *group_name)
1024 {
1025         static struct credentials c;
1026
1027         c.pass = getpwnam(user_name);
1028         if (!c.pass)
1029                 die("user not found - %s", user_name);
1030
1031         if (!group_name)
1032                 c.gid = c.pass->pw_gid;
1033         else {
1034                 struct group *group = getgrnam(group_name);
1035                 if (!group)
1036                         die("group not found - %s", group_name);
1037
1038                 c.gid = group->gr_gid;
1039         }
1040
1041         return &c;
1042 }
1043
1044 static void daemonize(void)
1045 {
1046         switch (fork()) {
1047                 case 0:
1048                         break;
1049                 case -1:
1050                         die_errno("fork failed");
1051                 default:
1052                         exit(0);
1053         }
1054         if (setsid() == -1)
1055                 die_errno("setsid failed");
1056         close(0);
1057         close(1);
1058         close(2);
1059         sanitize_stdfds();
1060 }
1061 #endif
1062
1063 static void store_pid(const char *path)
1064 {
1065         FILE *f = fopen(path, "w");
1066         if (!f)
1067                 die_errno("cannot open pid file '%s'", path);
1068         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1069                 die_errno("failed to write pid file '%s'", path);
1070 }
1071
1072 static int serve(struct string_list *listen_addr, int listen_port,
1073     struct credentials *cred)
1074 {
1075         struct socketlist socklist = { NULL, 0, 0 };
1076
1077         socksetup(listen_addr, listen_port, &socklist);
1078         if (socklist.nr == 0)
1079                 die("unable to allocate any listen sockets on port %u",
1080                     listen_port);
1081
1082         drop_privileges(cred);
1083
1084         return service_loop(&socklist);
1085 }
1086
1087 int main(int argc, char **argv)
1088 {
1089         int listen_port = 0;
1090         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1091         int serve_mode = 0, inetd_mode = 0;
1092         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1093         int detach = 0;
1094         struct credentials *cred = NULL;
1095         int i;
1096
1097         git_extract_argv0_path(argv[0]);
1098
1099         for (i = 1; i < argc; i++) {
1100                 char *arg = argv[i];
1101
1102                 if (!prefixcmp(arg, "--listen=")) {
1103                         string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1104                         continue;
1105                 }
1106                 if (!prefixcmp(arg, "--port=")) {
1107                         char *end;
1108                         unsigned long n;
1109                         n = strtoul(arg+7, &end, 0);
1110                         if (arg[7] && !*end) {
1111                                 listen_port = n;
1112                                 continue;
1113                         }
1114                 }
1115                 if (!strcmp(arg, "--serve")) {
1116                         serve_mode = 1;
1117                         continue;
1118                 }
1119                 if (!strcmp(arg, "--inetd")) {
1120                         inetd_mode = 1;
1121                         log_syslog = 1;
1122                         continue;
1123                 }
1124                 if (!strcmp(arg, "--verbose")) {
1125                         verbose = 1;
1126                         continue;
1127                 }
1128                 if (!strcmp(arg, "--syslog")) {
1129                         log_syslog = 1;
1130                         continue;
1131                 }
1132                 if (!strcmp(arg, "--export-all")) {
1133                         export_all_trees = 1;
1134                         continue;
1135                 }
1136                 if (!prefixcmp(arg, "--timeout=")) {
1137                         timeout = atoi(arg+10);
1138                         continue;
1139                 }
1140                 if (!prefixcmp(arg, "--init-timeout=")) {
1141                         init_timeout = atoi(arg+15);
1142                         continue;
1143                 }
1144                 if (!prefixcmp(arg, "--max-connections=")) {
1145                         max_connections = atoi(arg+18);
1146                         if (max_connections < 0)
1147                                 max_connections = 0;            /* unlimited */
1148                         continue;
1149                 }
1150                 if (!strcmp(arg, "--strict-paths")) {
1151                         strict_paths = 1;
1152                         continue;
1153                 }
1154                 if (!prefixcmp(arg, "--base-path=")) {
1155                         base_path = arg+12;
1156                         continue;
1157                 }
1158                 if (!strcmp(arg, "--base-path-relaxed")) {
1159                         base_path_relaxed = 1;
1160                         continue;
1161                 }
1162                 if (!prefixcmp(arg, "--interpolated-path=")) {
1163                         interpolated_path = arg+20;
1164                         continue;
1165                 }
1166                 if (!strcmp(arg, "--reuseaddr")) {
1167                         reuseaddr = 1;
1168                         continue;
1169                 }
1170                 if (!strcmp(arg, "--user-path")) {
1171                         user_path = "";
1172                         continue;
1173                 }
1174                 if (!prefixcmp(arg, "--user-path=")) {
1175                         user_path = arg + 12;
1176                         continue;
1177                 }
1178                 if (!prefixcmp(arg, "--pid-file=")) {
1179                         pid_file = arg + 11;
1180                         continue;
1181                 }
1182                 if (!strcmp(arg, "--detach")) {
1183                         detach = 1;
1184                         log_syslog = 1;
1185                         continue;
1186                 }
1187                 if (!prefixcmp(arg, "--user=")) {
1188                         user_name = arg + 7;
1189                         continue;
1190                 }
1191                 if (!prefixcmp(arg, "--group=")) {
1192                         group_name = arg + 8;
1193                         continue;
1194                 }
1195                 if (!prefixcmp(arg, "--enable=")) {
1196                         enable_service(arg + 9, 1);
1197                         continue;
1198                 }
1199                 if (!prefixcmp(arg, "--disable=")) {
1200                         enable_service(arg + 10, 0);
1201                         continue;
1202                 }
1203                 if (!prefixcmp(arg, "--allow-override=")) {
1204                         make_service_overridable(arg + 17, 1);
1205                         continue;
1206                 }
1207                 if (!prefixcmp(arg, "--forbid-override=")) {
1208                         make_service_overridable(arg + 18, 0);
1209                         continue;
1210                 }
1211                 if (!strcmp(arg, "--")) {
1212                         ok_paths = &argv[i+1];
1213                         break;
1214                 } else if (arg[0] != '-') {
1215                         ok_paths = &argv[i];
1216                         break;
1217                 }
1218
1219                 usage(daemon_usage);
1220         }
1221
1222         if (log_syslog) {
1223                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1224                 set_die_routine(daemon_die);
1225         } else
1226                 /* avoid splitting a message in the middle */
1227                 setvbuf(stderr, NULL, _IOFBF, 4096);
1228
1229         if (inetd_mode && (detach || group_name || user_name))
1230                 die("--detach, --user and --group are incompatible with --inetd");
1231
1232         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1233                 die("--listen= and --port= are incompatible with --inetd");
1234         else if (listen_port == 0)
1235                 listen_port = DEFAULT_GIT_PORT;
1236
1237         if (group_name && !user_name)
1238                 die("--group supplied without --user");
1239
1240         if (user_name)
1241                 cred = prepare_credentials(user_name, group_name);
1242
1243         if (strict_paths && (!ok_paths || !*ok_paths))
1244                 die("option --strict-paths requires a whitelist");
1245
1246         if (base_path && !is_directory(base_path))
1247                 die("base-path '%s' does not exist or is not a directory",
1248                     base_path);
1249
1250         if (inetd_mode) {
1251                 if (!freopen("/dev/null", "w", stderr))
1252                         die_errno("failed to redirect stderr to /dev/null");
1253         }
1254
1255         if (inetd_mode || serve_mode)
1256                 return execute();
1257
1258         if (detach) {
1259                 daemonize();
1260                 loginfo("Ready to rumble");
1261         }
1262         else
1263                 sanitize_stdfds();
1264
1265         if (pid_file)
1266                 store_pid(pid_file);
1267
1268         /* prepare argv for serving-processes */
1269         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1270         cld_argv[0] = argv[0];  /* git-daemon */
1271         cld_argv[1] = "--serve";
1272         for (i = 1; i < argc; ++i)
1273                 cld_argv[i+1] = argv[i];
1274         cld_argv[argc+1] = NULL;
1275
1276         return serve(&listen_addr, listen_port, cred);
1277 }