Merge branch 'kb/maint-submodule-savearg'
[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 #include <syslog.h>
9
10 #ifndef HOST_NAME_MAX
11 #define HOST_NAME_MAX 256
12 #endif
13
14 #ifndef NI_MAXSERV
15 #define NI_MAXSERV 32
16 #endif
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>] [--max-connections=<n>]\n"
25 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
26 "           [--user-path | --user-path=<path>]\n"
27 "           [--interpolated-path=<path>]\n"
28 "           [--reuseaddr] [--detach] [--pid-file=<file>]\n"
29 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
30 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
31 "                      [--user=<user> [--group=<group>]]\n"
32 "           [<directory>...]";
33
34 /* List of acceptable pathname prefixes */
35 static char **ok_paths;
36 static int strict_paths;
37
38 /* If this is set, git-daemon-export-ok is not required */
39 static int export_all_trees;
40
41 /* Take all paths relative to this one if non-NULL */
42 static char *base_path;
43 static char *interpolated_path;
44 static int base_path_relaxed;
45
46 /* Flag indicating client sent extra args. */
47 static int saw_extended_args;
48
49 /* If defined, ~user notation is allowed and the string is inserted
50  * after ~user/.  E.g. a request to git://host/~alice/frotz would
51  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
52  */
53 static const char *user_path;
54
55 /* Timeout, and initial timeout */
56 static unsigned int timeout;
57 static unsigned int init_timeout;
58
59 static char *hostname;
60 static char *canon_hostname;
61 static char *ip_address;
62 static char *tcp_port;
63
64 static void logreport(int priority, const char *err, va_list params)
65 {
66         if (log_syslog) {
67                 char buf[1024];
68                 vsnprintf(buf, sizeof(buf), err, params);
69                 syslog(priority, "%s", buf);
70         } else {
71                 /*
72                  * Since stderr is set to linebuffered mode, the
73                  * logging of different processes will not overlap
74                  */
75                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
76                 vfprintf(stderr, err, params);
77                 fputc('\n', stderr);
78         }
79 }
80
81 __attribute__((format (printf, 1, 2)))
82 static void logerror(const char *err, ...)
83 {
84         va_list params;
85         va_start(params, err);
86         logreport(LOG_ERR, err, params);
87         va_end(params);
88 }
89
90 __attribute__((format (printf, 1, 2)))
91 static void loginfo(const char *err, ...)
92 {
93         va_list params;
94         if (!verbose)
95                 return;
96         va_start(params, err);
97         logreport(LOG_INFO, err, params);
98         va_end(params);
99 }
100
101 static void NORETURN daemon_die(const char *err, va_list params)
102 {
103         logreport(LOG_ERR, err, params);
104         exit(1);
105 }
106
107 static char *path_ok(char *directory)
108 {
109         static char rpath[PATH_MAX];
110         static char interp_path[PATH_MAX];
111         char *path;
112         char *dir;
113
114         dir = directory;
115
116         if (daemon_avoid_alias(dir)) {
117                 logerror("'%s': aliased", dir);
118                 return NULL;
119         }
120
121         if (*dir == '~') {
122                 if (!user_path) {
123                         logerror("'%s': User-path not allowed", dir);
124                         return NULL;
125                 }
126                 if (*user_path) {
127                         /* Got either "~alice" or "~alice/foo";
128                          * rewrite them to "~alice/%s" or
129                          * "~alice/%s/foo".
130                          */
131                         int namlen, restlen = strlen(dir);
132                         char *slash = strchr(dir, '/');
133                         if (!slash)
134                                 slash = dir + restlen;
135                         namlen = slash - dir;
136                         restlen -= namlen;
137                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
138                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
139                                  namlen, dir, user_path, restlen, slash);
140                         dir = rpath;
141                 }
142         }
143         else if (interpolated_path && saw_extended_args) {
144                 struct strbuf expanded_path = STRBUF_INIT;
145                 struct strbuf_expand_dict_entry dict[6];
146
147                 dict[0].placeholder = "H"; dict[0].value = hostname;
148                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
149                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
150                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
151                 dict[4].placeholder = "D"; dict[4].value = directory;
152                 dict[5].placeholder = NULL; dict[5].value = NULL;
153                 if (*dir != '/') {
154                         /* Allow only absolute */
155                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
156                         return NULL;
157                 }
158
159                 strbuf_expand(&expanded_path, interpolated_path,
160                                 strbuf_expand_dict_cb, &dict);
161                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
162                 strbuf_release(&expanded_path);
163                 loginfo("Interpolated dir '%s'", interp_path);
164
165                 dir = interp_path;
166         }
167         else if (base_path) {
168                 if (*dir != '/') {
169                         /* Allow only absolute */
170                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
171                         return NULL;
172                 }
173                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
174                 dir = rpath;
175         }
176
177         path = enter_repo(dir, strict_paths);
178         if (!path && base_path && base_path_relaxed) {
179                 /*
180                  * if we fail and base_path_relaxed is enabled, try without
181                  * prefixing the base path
182                  */
183                 dir = directory;
184                 path = enter_repo(dir, strict_paths);
185         }
186
187         if (!path) {
188                 logerror("'%s' does not appear to be a git repository", dir);
189                 return NULL;
190         }
191
192         if ( ok_paths && *ok_paths ) {
193                 char **pp;
194                 int pathlen = strlen(path);
195
196                 /* The validation is done on the paths after enter_repo
197                  * appends optional {.git,.git/.git} and friends, but
198                  * it does not use getcwd().  So if your /pub is
199                  * a symlink to /mnt/pub, you can whitelist /pub and
200                  * do not have to say /mnt/pub.
201                  * Do not say /pub/.
202                  */
203                 for ( pp = ok_paths ; *pp ; pp++ ) {
204                         int len = strlen(*pp);
205                         if (len <= pathlen &&
206                             !memcmp(*pp, path, len) &&
207                             (path[len] == '\0' ||
208                              (!strict_paths && path[len] == '/')))
209                                 return path;
210                 }
211         }
212         else {
213                 /* be backwards compatible */
214                 if (!strict_paths)
215                         return path;
216         }
217
218         logerror("'%s': not in whitelist", path);
219         return NULL;            /* Fallthrough. Deny by default */
220 }
221
222 typedef int (*daemon_service_fn)(void);
223 struct daemon_service {
224         const char *name;
225         const char *config_name;
226         daemon_service_fn fn;
227         int enabled;
228         int overridable;
229 };
230
231 static struct daemon_service *service_looking_at;
232 static int service_enabled;
233
234 static int git_daemon_config(const char *var, const char *value, void *cb)
235 {
236         if (!prefixcmp(var, "daemon.") &&
237             !strcmp(var + 7, service_looking_at->config_name)) {
238                 service_enabled = git_config_bool(var, value);
239                 return 0;
240         }
241
242         /* we are not interested in parsing any other configuration here */
243         return 0;
244 }
245
246 static int run_service(char *dir, struct daemon_service *service)
247 {
248         const char *path;
249         int enabled = service->enabled;
250
251         loginfo("Request %s for '%s'", service->name, dir);
252
253         if (!enabled && !service->overridable) {
254                 logerror("'%s': service not enabled.", service->name);
255                 errno = EACCES;
256                 return -1;
257         }
258
259         if (!(path = path_ok(dir)))
260                 return -1;
261
262         /*
263          * Security on the cheap.
264          *
265          * We want a readable HEAD, usable "objects" directory, and
266          * a "git-daemon-export-ok" flag that says that the other side
267          * is ok with us doing this.
268          *
269          * path_ok() uses enter_repo() and does whitelist checking.
270          * We only need to make sure the repository is exported.
271          */
272
273         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
274                 logerror("'%s': repository not exported.", path);
275                 errno = EACCES;
276                 return -1;
277         }
278
279         if (service->overridable) {
280                 service_looking_at = service;
281                 service_enabled = -1;
282                 git_config(git_daemon_config, NULL);
283                 if (0 <= service_enabled)
284                         enabled = service_enabled;
285         }
286         if (!enabled) {
287                 logerror("'%s': service not enabled for '%s'",
288                          service->name, path);
289                 errno = EACCES;
290                 return -1;
291         }
292
293         /*
294          * We'll ignore SIGTERM from now on, we have a
295          * good client.
296          */
297         signal(SIGTERM, SIG_IGN);
298
299         return service->fn();
300 }
301
302 static void copy_to_log(int fd)
303 {
304         struct strbuf line = STRBUF_INIT;
305         FILE *fp;
306
307         fp = fdopen(fd, "r");
308         if (fp == NULL) {
309                 logerror("fdopen of error channel failed");
310                 close(fd);
311                 return;
312         }
313
314         while (strbuf_getline(&line, fp, '\n') != EOF) {
315                 logerror("%s", line.buf);
316                 strbuf_setlen(&line, 0);
317         }
318
319         strbuf_release(&line);
320         fclose(fp);
321 }
322
323 static int run_service_command(const char **argv)
324 {
325         struct child_process cld;
326
327         memset(&cld, 0, sizeof(cld));
328         cld.argv = argv;
329         cld.git_cmd = 1;
330         cld.err = -1;
331         if (start_command(&cld))
332                 return -1;
333
334         close(0);
335         close(1);
336
337         copy_to_log(cld.err);
338
339         return finish_command(&cld);
340 }
341
342 static int upload_pack(void)
343 {
344         /* Timeout as string */
345         char timeout_buf[64];
346         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
347
348         argv[2] = timeout_buf;
349
350         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
351         return run_service_command(argv);
352 }
353
354 static int upload_archive(void)
355 {
356         static const char *argv[] = { "upload-archive", ".", NULL };
357         return run_service_command(argv);
358 }
359
360 static int receive_pack(void)
361 {
362         static const char *argv[] = { "receive-pack", ".", NULL };
363         return run_service_command(argv);
364 }
365
366 static struct daemon_service daemon_service[] = {
367         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
368         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
369         { "receive-pack", "receivepack", receive_pack, 0, 1 },
370 };
371
372 static void enable_service(const char *name, int ena)
373 {
374         int i;
375         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
376                 if (!strcmp(daemon_service[i].name, name)) {
377                         daemon_service[i].enabled = ena;
378                         return;
379                 }
380         }
381         die("No such service %s", name);
382 }
383
384 static void make_service_overridable(const char *name, int ena)
385 {
386         int i;
387         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
388                 if (!strcmp(daemon_service[i].name, name)) {
389                         daemon_service[i].overridable = ena;
390                         return;
391                 }
392         }
393         die("No such service %s", name);
394 }
395
396 static char *xstrdup_tolower(const char *str)
397 {
398         char *p, *dup = xstrdup(str);
399         for (p = dup; *p; p++)
400                 *p = tolower(*p);
401         return dup;
402 }
403
404 static void parse_host_and_port(char *hostport, char **host,
405         char **port)
406 {
407         if (*hostport == '[') {
408                 char *end;
409
410                 end = strchr(hostport, ']');
411                 if (!end)
412                         die("Invalid request ('[' without ']')");
413                 *end = '\0';
414                 *host = hostport + 1;
415                 if (!end[1])
416                         *port = NULL;
417                 else if (end[1] == ':')
418                         *port = end + 2;
419                 else
420                         die("Garbage after end of host part");
421         } else {
422                 *host = hostport;
423                 *port = strrchr(hostport, ':');
424                 if (*port) {
425                         **port = '\0';
426                         ++*port;
427                 }
428         }
429 }
430
431 /*
432  * Read the host as supplied by the client connection.
433  */
434 static void parse_host_arg(char *extra_args, int buflen)
435 {
436         char *val;
437         int vallen;
438         char *end = extra_args + buflen;
439
440         if (extra_args < end && *extra_args) {
441                 saw_extended_args = 1;
442                 if (strncasecmp("host=", extra_args, 5) == 0) {
443                         val = extra_args + 5;
444                         vallen = strlen(val) + 1;
445                         if (*val) {
446                                 /* Split <host>:<port> at colon. */
447                                 char *host;
448                                 char *port;
449                                 parse_host_and_port(val, &host, &port);
450                                 if (port) {
451                                         free(tcp_port);
452                                         tcp_port = xstrdup(port);
453                                 }
454                                 free(hostname);
455                                 hostname = xstrdup_tolower(host);
456                         }
457
458                         /* On to the next one */
459                         extra_args = val + vallen;
460                 }
461                 if (extra_args < end && *extra_args)
462                         die("Invalid request");
463         }
464
465         /*
466          * Locate canonical hostname and its IP address.
467          */
468         if (hostname) {
469 #ifndef NO_IPV6
470                 struct addrinfo hints;
471                 struct addrinfo *ai;
472                 int gai;
473                 static char addrbuf[HOST_NAME_MAX + 1];
474
475                 memset(&hints, 0, sizeof(hints));
476                 hints.ai_flags = AI_CANONNAME;
477
478                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
479                 if (!gai) {
480                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
481
482                         inet_ntop(AF_INET, &sin_addr->sin_addr,
483                                   addrbuf, sizeof(addrbuf));
484                         free(ip_address);
485                         ip_address = xstrdup(addrbuf);
486
487                         free(canon_hostname);
488                         canon_hostname = xstrdup(ai->ai_canonname ?
489                                                  ai->ai_canonname : ip_address);
490
491                         freeaddrinfo(ai);
492                 }
493 #else
494                 struct hostent *hent;
495                 struct sockaddr_in sa;
496                 char **ap;
497                 static char addrbuf[HOST_NAME_MAX + 1];
498
499                 hent = gethostbyname(hostname);
500
501                 ap = hent->h_addr_list;
502                 memset(&sa, 0, sizeof sa);
503                 sa.sin_family = hent->h_addrtype;
504                 sa.sin_port = htons(0);
505                 memcpy(&sa.sin_addr, *ap, hent->h_length);
506
507                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
508                           addrbuf, sizeof(addrbuf));
509
510                 free(canon_hostname);
511                 canon_hostname = xstrdup(hent->h_name);
512                 free(ip_address);
513                 ip_address = xstrdup(addrbuf);
514 #endif
515         }
516 }
517
518
519 static int execute(struct sockaddr *addr)
520 {
521         static char line[1000];
522         int pktlen, len, i;
523
524         if (addr) {
525                 char addrbuf[256] = "";
526                 int port = -1;
527
528                 if (addr->sa_family == AF_INET) {
529                         struct sockaddr_in *sin_addr = (void *) addr;
530                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
531                         port = ntohs(sin_addr->sin_port);
532 #ifndef NO_IPV6
533                 } else if (addr && addr->sa_family == AF_INET6) {
534                         struct sockaddr_in6 *sin6_addr = (void *) addr;
535
536                         char *buf = addrbuf;
537                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
538                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
539                         strcat(buf, "]");
540
541                         port = ntohs(sin6_addr->sin6_port);
542 #endif
543                 }
544                 loginfo("Connection from %s:%d", addrbuf, port);
545                 setenv("REMOTE_ADDR", addrbuf, 1);
546         }
547         else {
548                 unsetenv("REMOTE_ADDR");
549         }
550
551         alarm(init_timeout ? init_timeout : timeout);
552         pktlen = packet_read_line(0, line, sizeof(line));
553         alarm(0);
554
555         len = strlen(line);
556         if (pktlen != len)
557                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
558                         (int) pktlen - len,
559                         (int) pktlen - len, line + len + 1);
560         if (len && line[len-1] == '\n') {
561                 line[--len] = 0;
562                 pktlen--;
563         }
564
565         free(hostname);
566         free(canon_hostname);
567         free(ip_address);
568         free(tcp_port);
569         hostname = canon_hostname = ip_address = tcp_port = NULL;
570
571         if (len != pktlen)
572                 parse_host_arg(line + len + 1, pktlen - len - 1);
573
574         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
575                 struct daemon_service *s = &(daemon_service[i]);
576                 int namelen = strlen(s->name);
577                 if (!prefixcmp(line, "git-") &&
578                     !strncmp(s->name, line + 4, namelen) &&
579                     line[namelen + 4] == ' ') {
580                         /*
581                          * Note: The directory here is probably context sensitive,
582                          * and might depend on the actual service being performed.
583                          */
584                         return run_service(line + namelen + 5, s);
585                 }
586         }
587
588         logerror("Protocol error: '%s'", line);
589         return -1;
590 }
591
592 static int addrcmp(const struct sockaddr_storage *s1,
593     const struct sockaddr_storage *s2)
594 {
595         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
596         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
597
598         if (sa1->sa_family != sa2->sa_family)
599                 return sa1->sa_family - sa2->sa_family;
600         if (sa1->sa_family == AF_INET)
601                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
602                     &((struct sockaddr_in *)s2)->sin_addr,
603                     sizeof(struct in_addr));
604 #ifndef NO_IPV6
605         if (sa1->sa_family == AF_INET6)
606                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
607                     &((struct sockaddr_in6 *)s2)->sin6_addr,
608                     sizeof(struct in6_addr));
609 #endif
610         return 0;
611 }
612
613 static int max_connections = 32;
614
615 static unsigned int live_children;
616
617 static struct child {
618         struct child *next;
619         pid_t pid;
620         struct sockaddr_storage address;
621 } *firstborn;
622
623 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
624 {
625         struct child *newborn, **cradle;
626
627         newborn = xcalloc(1, sizeof(*newborn));
628         live_children++;
629         newborn->pid = pid;
630         memcpy(&newborn->address, addr, addrlen);
631         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
632                 if (!addrcmp(&(*cradle)->address, &newborn->address))
633                         break;
634         newborn->next = *cradle;
635         *cradle = newborn;
636 }
637
638 static void remove_child(pid_t pid)
639 {
640         struct child **cradle, *blanket;
641
642         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
643                 if (blanket->pid == pid) {
644                         *cradle = blanket->next;
645                         live_children--;
646                         free(blanket);
647                         break;
648                 }
649 }
650
651 /*
652  * This gets called if the number of connections grows
653  * past "max_connections".
654  *
655  * We kill the newest connection from a duplicate IP.
656  */
657 static void kill_some_child(void)
658 {
659         const struct child *blanket, *next;
660
661         if (!(blanket = firstborn))
662                 return;
663
664         for (; (next = blanket->next); blanket = next)
665                 if (!addrcmp(&blanket->address, &next->address)) {
666                         kill(blanket->pid, SIGTERM);
667                         break;
668                 }
669 }
670
671 static void check_dead_children(void)
672 {
673         int status;
674         pid_t pid;
675
676         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
677                 const char *dead = "";
678                 remove_child(pid);
679                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
680                         dead = " (with error)";
681                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
682         }
683 }
684
685 static void handle(int incoming, struct sockaddr *addr, int addrlen)
686 {
687         pid_t pid;
688
689         if (max_connections && live_children >= max_connections) {
690                 kill_some_child();
691                 sleep(1);  /* give it some time to die */
692                 check_dead_children();
693                 if (live_children >= max_connections) {
694                         close(incoming);
695                         logerror("Too many children, dropping connection");
696                         return;
697                 }
698         }
699
700         if ((pid = fork())) {
701                 close(incoming);
702                 if (pid < 0) {
703                         logerror("Couldn't fork %s", strerror(errno));
704                         return;
705                 }
706
707                 add_child(pid, addr, addrlen);
708                 return;
709         }
710
711         dup2(incoming, 0);
712         dup2(incoming, 1);
713         close(incoming);
714
715         exit(execute(addr));
716 }
717
718 static void child_handler(int signo)
719 {
720         /*
721          * Otherwise empty handler because systemcalls will get interrupted
722          * upon signal receipt
723          * SysV needs the handler to be rearmed
724          */
725         signal(SIGCHLD, child_handler);
726 }
727
728 static int set_reuse_addr(int sockfd)
729 {
730         int on = 1;
731
732         if (!reuseaddr)
733                 return 0;
734         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
735                           &on, sizeof(on));
736 }
737
738 struct socketlist {
739         int *list;
740         size_t nr;
741         size_t alloc;
742 };
743
744 #ifndef NO_IPV6
745
746 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
747 {
748         int socknum = 0;
749         int maxfd = -1;
750         char pbuf[NI_MAXSERV];
751         struct addrinfo hints, *ai0, *ai;
752         int gai;
753         long flags;
754
755         sprintf(pbuf, "%d", listen_port);
756         memset(&hints, 0, sizeof(hints));
757         hints.ai_family = AF_UNSPEC;
758         hints.ai_socktype = SOCK_STREAM;
759         hints.ai_protocol = IPPROTO_TCP;
760         hints.ai_flags = AI_PASSIVE;
761
762         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
763         if (gai) {
764                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
765                 return 0;
766         }
767
768         for (ai = ai0; ai; ai = ai->ai_next) {
769                 int sockfd;
770
771                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
772                 if (sockfd < 0)
773                         continue;
774                 if (sockfd >= FD_SETSIZE) {
775                         logerror("Socket descriptor too large");
776                         close(sockfd);
777                         continue;
778                 }
779
780 #ifdef IPV6_V6ONLY
781                 if (ai->ai_family == AF_INET6) {
782                         int on = 1;
783                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
784                                    &on, sizeof(on));
785                         /* Note: error is not fatal */
786                 }
787 #endif
788
789                 if (set_reuse_addr(sockfd)) {
790                         close(sockfd);
791                         continue;
792                 }
793
794                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
795                         close(sockfd);
796                         continue;       /* not fatal */
797                 }
798                 if (listen(sockfd, 5) < 0) {
799                         close(sockfd);
800                         continue;       /* not fatal */
801                 }
802
803                 flags = fcntl(sockfd, F_GETFD, 0);
804                 if (flags >= 0)
805                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
806
807                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
808                 socklist->list[socklist->nr++] = sockfd;
809                 socknum++;
810
811                 if (maxfd < sockfd)
812                         maxfd = sockfd;
813         }
814
815         freeaddrinfo(ai0);
816
817         return socknum;
818 }
819
820 #else /* NO_IPV6 */
821
822 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
823 {
824         struct sockaddr_in sin;
825         int sockfd;
826         long flags;
827
828         memset(&sin, 0, sizeof sin);
829         sin.sin_family = AF_INET;
830         sin.sin_port = htons(listen_port);
831
832         if (listen_addr) {
833                 /* Well, host better be an IP address here. */
834                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
835                         return 0;
836         } else {
837                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
838         }
839
840         sockfd = socket(AF_INET, SOCK_STREAM, 0);
841         if (sockfd < 0)
842                 return 0;
843
844         if (set_reuse_addr(sockfd)) {
845                 close(sockfd);
846                 return 0;
847         }
848
849         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
850                 close(sockfd);
851                 return 0;
852         }
853
854         if (listen(sockfd, 5) < 0) {
855                 close(sockfd);
856                 return 0;
857         }
858
859         flags = fcntl(sockfd, F_GETFD, 0);
860         if (flags >= 0)
861                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
862
863         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
864         socklist->list[socklist->nr++] = sockfd;
865         return 1;
866 }
867
868 #endif
869
870 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
871 {
872         if (!listen_addr->nr)
873                 setup_named_sock(NULL, listen_port, socklist);
874         else {
875                 int i, socknum;
876                 for (i = 0; i < listen_addr->nr; i++) {
877                         socknum = setup_named_sock(listen_addr->items[i].string,
878                                                    listen_port, socklist);
879
880                         if (socknum == 0)
881                                 logerror("unable to allocate any listen sockets for host %s on port %u",
882                                          listen_addr->items[i].string, listen_port);
883                 }
884         }
885 }
886
887 static int service_loop(struct socketlist *socklist)
888 {
889         struct pollfd *pfd;
890         int i;
891
892         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
893
894         for (i = 0; i < socklist->nr; i++) {
895                 pfd[i].fd = socklist->list[i];
896                 pfd[i].events = POLLIN;
897         }
898
899         signal(SIGCHLD, child_handler);
900
901         for (;;) {
902                 int i;
903
904                 check_dead_children();
905
906                 if (poll(pfd, socklist->nr, -1) < 0) {
907                         if (errno != EINTR) {
908                                 logerror("Poll failed, resuming: %s",
909                                       strerror(errno));
910                                 sleep(1);
911                         }
912                         continue;
913                 }
914
915                 for (i = 0; i < socklist->nr; i++) {
916                         if (pfd[i].revents & POLLIN) {
917                                 struct sockaddr_storage ss;
918                                 unsigned int sslen = sizeof(ss);
919                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
920                                 if (incoming < 0) {
921                                         switch (errno) {
922                                         case EAGAIN:
923                                         case EINTR:
924                                         case ECONNABORTED:
925                                                 continue;
926                                         default:
927                                                 die_errno("accept returned");
928                                         }
929                                 }
930                                 handle(incoming, (struct sockaddr *)&ss, sslen);
931                         }
932                 }
933         }
934 }
935
936 /* if any standard file descriptor is missing open it to /dev/null */
937 static void sanitize_stdfds(void)
938 {
939         int fd = open("/dev/null", O_RDWR, 0);
940         while (fd != -1 && fd < 2)
941                 fd = dup(fd);
942         if (fd == -1)
943                 die_errno("open /dev/null or dup failed");
944         if (fd > 2)
945                 close(fd);
946 }
947
948 static void daemonize(void)
949 {
950         switch (fork()) {
951                 case 0:
952                         break;
953                 case -1:
954                         die_errno("fork failed");
955                 default:
956                         exit(0);
957         }
958         if (setsid() == -1)
959                 die_errno("setsid failed");
960         close(0);
961         close(1);
962         close(2);
963         sanitize_stdfds();
964 }
965
966 static void store_pid(const char *path)
967 {
968         FILE *f = fopen(path, "w");
969         if (!f)
970                 die_errno("cannot open pid file '%s'", path);
971         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
972                 die_errno("failed to write pid file '%s'", path);
973 }
974
975 static int serve(struct string_list *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
976 {
977         struct socketlist socklist = { NULL, 0, 0 };
978
979         socksetup(listen_addr, listen_port, &socklist);
980         if (socklist.nr == 0)
981                 die("unable to allocate any listen sockets on port %u",
982                     listen_port);
983
984         if (pass && gid &&
985             (initgroups(pass->pw_name, gid) || setgid (gid) ||
986              setuid(pass->pw_uid)))
987                 die("cannot drop privileges");
988
989         return service_loop(&socklist);
990 }
991
992 int main(int argc, char **argv)
993 {
994         int listen_port = 0;
995         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
996         int inetd_mode = 0;
997         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
998         int detach = 0;
999         struct passwd *pass = NULL;
1000         struct group *group;
1001         gid_t gid = 0;
1002         int i;
1003
1004         git_extract_argv0_path(argv[0]);
1005
1006         for (i = 1; i < argc; i++) {
1007                 char *arg = argv[i];
1008
1009                 if (!prefixcmp(arg, "--listen=")) {
1010                         string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1011                         continue;
1012                 }
1013                 if (!prefixcmp(arg, "--port=")) {
1014                         char *end;
1015                         unsigned long n;
1016                         n = strtoul(arg+7, &end, 0);
1017                         if (arg[7] && !*end) {
1018                                 listen_port = n;
1019                                 continue;
1020                         }
1021                 }
1022                 if (!strcmp(arg, "--inetd")) {
1023                         inetd_mode = 1;
1024                         log_syslog = 1;
1025                         continue;
1026                 }
1027                 if (!strcmp(arg, "--verbose")) {
1028                         verbose = 1;
1029                         continue;
1030                 }
1031                 if (!strcmp(arg, "--syslog")) {
1032                         log_syslog = 1;
1033                         continue;
1034                 }
1035                 if (!strcmp(arg, "--export-all")) {
1036                         export_all_trees = 1;
1037                         continue;
1038                 }
1039                 if (!prefixcmp(arg, "--timeout=")) {
1040                         timeout = atoi(arg+10);
1041                         continue;
1042                 }
1043                 if (!prefixcmp(arg, "--init-timeout=")) {
1044                         init_timeout = atoi(arg+15);
1045                         continue;
1046                 }
1047                 if (!prefixcmp(arg, "--max-connections=")) {
1048                         max_connections = atoi(arg+18);
1049                         if (max_connections < 0)
1050                                 max_connections = 0;            /* unlimited */
1051                         continue;
1052                 }
1053                 if (!strcmp(arg, "--strict-paths")) {
1054                         strict_paths = 1;
1055                         continue;
1056                 }
1057                 if (!prefixcmp(arg, "--base-path=")) {
1058                         base_path = arg+12;
1059                         continue;
1060                 }
1061                 if (!strcmp(arg, "--base-path-relaxed")) {
1062                         base_path_relaxed = 1;
1063                         continue;
1064                 }
1065                 if (!prefixcmp(arg, "--interpolated-path=")) {
1066                         interpolated_path = arg+20;
1067                         continue;
1068                 }
1069                 if (!strcmp(arg, "--reuseaddr")) {
1070                         reuseaddr = 1;
1071                         continue;
1072                 }
1073                 if (!strcmp(arg, "--user-path")) {
1074                         user_path = "";
1075                         continue;
1076                 }
1077                 if (!prefixcmp(arg, "--user-path=")) {
1078                         user_path = arg + 12;
1079                         continue;
1080                 }
1081                 if (!prefixcmp(arg, "--pid-file=")) {
1082                         pid_file = arg + 11;
1083                         continue;
1084                 }
1085                 if (!strcmp(arg, "--detach")) {
1086                         detach = 1;
1087                         log_syslog = 1;
1088                         continue;
1089                 }
1090                 if (!prefixcmp(arg, "--user=")) {
1091                         user_name = arg + 7;
1092                         continue;
1093                 }
1094                 if (!prefixcmp(arg, "--group=")) {
1095                         group_name = arg + 8;
1096                         continue;
1097                 }
1098                 if (!prefixcmp(arg, "--enable=")) {
1099                         enable_service(arg + 9, 1);
1100                         continue;
1101                 }
1102                 if (!prefixcmp(arg, "--disable=")) {
1103                         enable_service(arg + 10, 0);
1104                         continue;
1105                 }
1106                 if (!prefixcmp(arg, "--allow-override=")) {
1107                         make_service_overridable(arg + 17, 1);
1108                         continue;
1109                 }
1110                 if (!prefixcmp(arg, "--forbid-override=")) {
1111                         make_service_overridable(arg + 18, 0);
1112                         continue;
1113                 }
1114                 if (!strcmp(arg, "--")) {
1115                         ok_paths = &argv[i+1];
1116                         break;
1117                 } else if (arg[0] != '-') {
1118                         ok_paths = &argv[i];
1119                         break;
1120                 }
1121
1122                 usage(daemon_usage);
1123         }
1124
1125         if (log_syslog) {
1126                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1127                 set_die_routine(daemon_die);
1128         } else
1129                 /* avoid splitting a message in the middle */
1130                 setvbuf(stderr, NULL, _IOLBF, 0);
1131
1132         if (inetd_mode && (group_name || user_name))
1133                 die("--user and --group are incompatible with --inetd");
1134
1135         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1136                 die("--listen= and --port= are incompatible with --inetd");
1137         else if (listen_port == 0)
1138                 listen_port = DEFAULT_GIT_PORT;
1139
1140         if (group_name && !user_name)
1141                 die("--group supplied without --user");
1142
1143         if (user_name) {
1144                 pass = getpwnam(user_name);
1145                 if (!pass)
1146                         die("user not found - %s", user_name);
1147
1148                 if (!group_name)
1149                         gid = pass->pw_gid;
1150                 else {
1151                         group = getgrnam(group_name);
1152                         if (!group)
1153                                 die("group not found - %s", group_name);
1154
1155                         gid = group->gr_gid;
1156                 }
1157         }
1158
1159         if (strict_paths && (!ok_paths || !*ok_paths))
1160                 die("option --strict-paths requires a whitelist");
1161
1162         if (base_path && !is_directory(base_path))
1163                 die("base-path '%s' does not exist or is not a directory",
1164                     base_path);
1165
1166         if (inetd_mode) {
1167                 struct sockaddr_storage ss;
1168                 struct sockaddr *peer = (struct sockaddr *)&ss;
1169                 socklen_t slen = sizeof(ss);
1170
1171                 if (!freopen("/dev/null", "w", stderr))
1172                         die_errno("failed to redirect stderr to /dev/null");
1173
1174                 if (getpeername(0, peer, &slen))
1175                         peer = NULL;
1176
1177                 return execute(peer);
1178         }
1179
1180         if (detach) {
1181                 daemonize();
1182                 loginfo("Ready to rumble");
1183         }
1184         else
1185                 sanitize_stdfds();
1186
1187         if (pid_file)
1188                 store_pid(pid_file);
1189
1190         return serve(&listen_addr, listen_port, pass, gid);
1191 }