Sync with 1.6.5.5
[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
7 #include <syslog.h>
8
9 #ifndef HOST_NAME_MAX
10 #define HOST_NAME_MAX 256
11 #endif
12
13 #ifndef NI_MAXSERV
14 #define NI_MAXSERV 32
15 #endif
16
17 static int log_syslog;
18 static int verbose;
19 static int reuseaddr;
20
21 static const char daemon_usage[] =
22 "git daemon [--verbose] [--syslog] [--export-all]\n"
23 "           [--timeout=n] [--init-timeout=n] [--max-connections=n]\n"
24 "           [--strict-paths] [--base-path=path] [--base-path-relaxed]\n"
25 "           [--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 static int base_path_relaxed;
44
45 /* Flag indicating client sent extra args. */
46 static int saw_extended_args;
47
48 /* If defined, ~user notation is allowed and the string is inserted
49  * after ~user/.  E.g. a request to git://host/~alice/frotz would
50  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
51  */
52 static const char *user_path;
53
54 /* Timeout, and initial timeout */
55 static unsigned int timeout;
56 static unsigned int init_timeout;
57
58 static char *hostname;
59 static char *canon_hostname;
60 static char *ip_address;
61 static char *tcp_port;
62
63 static void logreport(int priority, const char *err, va_list params)
64 {
65         if (log_syslog) {
66                 char buf[1024];
67                 vsnprintf(buf, sizeof(buf), err, params);
68                 syslog(priority, "%s", buf);
69         } else {
70                 /*
71                  * Since stderr is set to linebuffered mode, the
72                  * logging of different processes will not overlap
73                  */
74                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
75                 vfprintf(stderr, err, params);
76                 fputc('\n', stderr);
77         }
78 }
79
80 __attribute__((format (printf, 1, 2)))
81 static void logerror(const char *err, ...)
82 {
83         va_list params;
84         va_start(params, err);
85         logreport(LOG_ERR, err, params);
86         va_end(params);
87 }
88
89 __attribute__((format (printf, 1, 2)))
90 static void loginfo(const char *err, ...)
91 {
92         va_list params;
93         if (!verbose)
94                 return;
95         va_start(params, err);
96         logreport(LOG_INFO, err, params);
97         va_end(params);
98 }
99
100 static void NORETURN daemon_die(const char *err, va_list params)
101 {
102         logreport(LOG_ERR, err, params);
103         exit(1);
104 }
105
106 static char *path_ok(char *directory)
107 {
108         static char rpath[PATH_MAX];
109         static char interp_path[PATH_MAX];
110         char *path;
111         char *dir;
112
113         dir = directory;
114
115         if (daemon_avoid_alias(dir)) {
116                 logerror("'%s': aliased", dir);
117                 return NULL;
118         }
119
120         if (*dir == '~') {
121                 if (!user_path) {
122                         logerror("'%s': User-path not allowed", dir);
123                         return NULL;
124                 }
125                 if (*user_path) {
126                         /* Got either "~alice" or "~alice/foo";
127                          * rewrite them to "~alice/%s" or
128                          * "~alice/%s/foo".
129                          */
130                         int namlen, restlen = strlen(dir);
131                         char *slash = strchr(dir, '/');
132                         if (!slash)
133                                 slash = dir + restlen;
134                         namlen = slash - dir;
135                         restlen -= namlen;
136                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
137                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
138                                  namlen, dir, user_path, restlen, slash);
139                         dir = rpath;
140                 }
141         }
142         else if (interpolated_path && saw_extended_args) {
143                 struct strbuf expanded_path = STRBUF_INIT;
144                 struct strbuf_expand_dict_entry dict[] = {
145                         { "H", hostname },
146                         { "CH", canon_hostname },
147                         { "IP", ip_address },
148                         { "P", tcp_port },
149                         { "D", directory },
150                         { "%", "%" },
151                         { NULL }
152                 };
153
154                 if (*dir != '/') {
155                         /* Allow only absolute */
156                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
157                         return NULL;
158                 }
159
160                 strbuf_expand(&expanded_path, interpolated_path,
161                                 strbuf_expand_dict_cb, &dict);
162                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
163                 strbuf_release(&expanded_path);
164                 loginfo("Interpolated dir '%s'", interp_path);
165
166                 dir = interp_path;
167         }
168         else if (base_path) {
169                 if (*dir != '/') {
170                         /* Allow only absolute */
171                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
172                         return NULL;
173                 }
174                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
175                 dir = rpath;
176         }
177
178         path = enter_repo(dir, strict_paths);
179         if (!path && base_path && base_path_relaxed) {
180                 /*
181                  * if we fail and base_path_relaxed is enabled, try without
182                  * prefixing the base path
183                  */
184                 dir = directory;
185                 path = enter_repo(dir, strict_paths);
186         }
187
188         if (!path) {
189                 logerror("'%s' does not appear to be a git repository", dir);
190                 return NULL;
191         }
192
193         if ( ok_paths && *ok_paths ) {
194                 char **pp;
195                 int pathlen = strlen(path);
196
197                 /* The validation is done on the paths after enter_repo
198                  * appends optional {.git,.git/.git} and friends, but
199                  * it does not use getcwd().  So if your /pub is
200                  * a symlink to /mnt/pub, you can whitelist /pub and
201                  * do not have to say /mnt/pub.
202                  * Do not say /pub/.
203                  */
204                 for ( pp = ok_paths ; *pp ; pp++ ) {
205                         int len = strlen(*pp);
206                         if (len <= pathlen &&
207                             !memcmp(*pp, path, len) &&
208                             (path[len] == '\0' ||
209                              (!strict_paths && path[len] == '/')))
210                                 return path;
211                 }
212         }
213         else {
214                 /* be backwards compatible */
215                 if (!strict_paths)
216                         return path;
217         }
218
219         logerror("'%s': not in whitelist", path);
220         return NULL;            /* Fallthrough. Deny by default */
221 }
222
223 typedef int (*daemon_service_fn)(void);
224 struct daemon_service {
225         const char *name;
226         const char *config_name;
227         daemon_service_fn fn;
228         int enabled;
229         int overridable;
230 };
231
232 static struct daemon_service *service_looking_at;
233 static int service_enabled;
234
235 static int git_daemon_config(const char *var, const char *value, void *cb)
236 {
237         if (!prefixcmp(var, "daemon.") &&
238             !strcmp(var + 7, service_looking_at->config_name)) {
239                 service_enabled = git_config_bool(var, value);
240                 return 0;
241         }
242
243         /* we are not interested in parsing any other configuration here */
244         return 0;
245 }
246
247 static int run_service(char *dir, struct daemon_service *service)
248 {
249         const char *path;
250         int enabled = service->enabled;
251
252         loginfo("Request %s for '%s'", service->name, dir);
253
254         if (!enabled && !service->overridable) {
255                 logerror("'%s': service not enabled.", service->name);
256                 errno = EACCES;
257                 return -1;
258         }
259
260         if (!(path = path_ok(dir)))
261                 return -1;
262
263         /*
264          * Security on the cheap.
265          *
266          * We want a readable HEAD, usable "objects" directory, and
267          * a "git-daemon-export-ok" flag that says that the other side
268          * is ok with us doing this.
269          *
270          * path_ok() uses enter_repo() and does whitelist checking.
271          * We only need to make sure the repository is exported.
272          */
273
274         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
275                 logerror("'%s': repository not exported.", path);
276                 errno = EACCES;
277                 return -1;
278         }
279
280         if (service->overridable) {
281                 service_looking_at = service;
282                 service_enabled = -1;
283                 git_config(git_daemon_config, NULL);
284                 if (0 <= service_enabled)
285                         enabled = service_enabled;
286         }
287         if (!enabled) {
288                 logerror("'%s': service not enabled for '%s'",
289                          service->name, path);
290                 errno = EACCES;
291                 return -1;
292         }
293
294         /*
295          * We'll ignore SIGTERM from now on, we have a
296          * good client.
297          */
298         signal(SIGTERM, SIG_IGN);
299
300         return service->fn();
301 }
302
303 static void copy_to_log(int fd)
304 {
305         struct strbuf line = STRBUF_INIT;
306         FILE *fp;
307
308         fp = fdopen(fd, "r");
309         if (fp == NULL) {
310                 logerror("fdopen of error channel failed");
311                 close(fd);
312                 return;
313         }
314
315         while (strbuf_getline(&line, fp, '\n') != EOF) {
316                 logerror("%s", line.buf);
317                 strbuf_setlen(&line, 0);
318         }
319
320         strbuf_release(&line);
321         fclose(fp);
322 }
323
324 static int run_service_command(const char **argv)
325 {
326         struct child_process cld;
327
328         memset(&cld, 0, sizeof(cld));
329         cld.argv = argv;
330         cld.git_cmd = 1;
331         cld.err = -1;
332         if (start_command(&cld))
333                 return -1;
334
335         close(0);
336         close(1);
337
338         copy_to_log(cld.err);
339
340         return finish_command(&cld);
341 }
342
343 static int upload_pack(void)
344 {
345         /* Timeout as string */
346         char timeout_buf[64];
347         const char *argv[] = { "upload-pack", "--strict", timeout_buf, ".", NULL };
348
349         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
350         return run_service_command(argv);
351 }
352
353 static int upload_archive(void)
354 {
355         static const char *argv[] = { "upload-archive", ".", NULL };
356         return run_service_command(argv);
357 }
358
359 static int receive_pack(void)
360 {
361         static const char *argv[] = { "receive-pack", ".", NULL };
362         return run_service_command(argv);
363 }
364
365 static struct daemon_service daemon_service[] = {
366         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
367         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
368         { "receive-pack", "receivepack", receive_pack, 0, 1 },
369 };
370
371 static void enable_service(const char *name, int ena)
372 {
373         int i;
374         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
375                 if (!strcmp(daemon_service[i].name, name)) {
376                         daemon_service[i].enabled = ena;
377                         return;
378                 }
379         }
380         die("No such service %s", name);
381 }
382
383 static void make_service_overridable(const char *name, int ena)
384 {
385         int i;
386         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
387                 if (!strcmp(daemon_service[i].name, name)) {
388                         daemon_service[i].overridable = ena;
389                         return;
390                 }
391         }
392         die("No such service %s", name);
393 }
394
395 static char *xstrdup_tolower(const char *str)
396 {
397         char *p, *dup = xstrdup(str);
398         for (p = dup; *p; p++)
399                 *p = tolower(*p);
400         return dup;
401 }
402
403 /*
404  * Read the host as supplied by the client connection.
405  */
406 static void parse_host_arg(char *extra_args, int buflen)
407 {
408         char *val;
409         int vallen;
410         char *end = extra_args + buflen;
411
412         if (extra_args < end && *extra_args) {
413                 saw_extended_args = 1;
414                 if (strncasecmp("host=", extra_args, 5) == 0) {
415                         val = extra_args + 5;
416                         vallen = strlen(val) + 1;
417                         if (*val) {
418                                 /* Split <host>:<port> at colon. */
419                                 char *host = val;
420                                 char *port = strrchr(host, ':');
421                                 if (port) {
422                                         *port = 0;
423                                         port++;
424                                         free(tcp_port);
425                                         tcp_port = xstrdup(port);
426                                 }
427                                 free(hostname);
428                                 hostname = xstrdup_tolower(host);
429                         }
430
431                         /* On to the next one */
432                         extra_args = val + vallen;
433                 }
434                 if (extra_args < end && *extra_args)
435                         die("Invalid request");
436         }
437
438         /*
439          * Locate canonical hostname and its IP address.
440          */
441         if (hostname) {
442 #ifndef NO_IPV6
443                 struct addrinfo hints;
444                 struct addrinfo *ai;
445                 int gai;
446                 static char addrbuf[HOST_NAME_MAX + 1];
447
448                 memset(&hints, 0, sizeof(hints));
449                 hints.ai_flags = AI_CANONNAME;
450
451                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
452                 if (!gai) {
453                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
454
455                         inet_ntop(AF_INET, &sin_addr->sin_addr,
456                                   addrbuf, sizeof(addrbuf));
457                         free(ip_address);
458                         ip_address = xstrdup(addrbuf);
459
460                         free(canon_hostname);
461                         canon_hostname = xstrdup(ai->ai_canonname ?
462                                                  ai->ai_canonname : ip_address);
463
464                         freeaddrinfo(ai);
465                 }
466 #else
467                 struct hostent *hent;
468                 struct sockaddr_in sa;
469                 char **ap;
470                 static char addrbuf[HOST_NAME_MAX + 1];
471
472                 hent = gethostbyname(hostname);
473
474                 ap = hent->h_addr_list;
475                 memset(&sa, 0, sizeof sa);
476                 sa.sin_family = hent->h_addrtype;
477                 sa.sin_port = htons(0);
478                 memcpy(&sa.sin_addr, *ap, hent->h_length);
479
480                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
481                           addrbuf, sizeof(addrbuf));
482
483                 free(canon_hostname);
484                 canon_hostname = xstrdup(hent->h_name);
485                 free(ip_address);
486                 ip_address = xstrdup(addrbuf);
487 #endif
488         }
489 }
490
491
492 static int execute(struct sockaddr *addr)
493 {
494         static char line[1000];
495         int pktlen, len, i;
496
497         if (addr) {
498                 char addrbuf[256] = "";
499                 int port = -1;
500
501                 if (addr->sa_family == AF_INET) {
502                         struct sockaddr_in *sin_addr = (void *) addr;
503                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
504                         port = ntohs(sin_addr->sin_port);
505 #ifndef NO_IPV6
506                 } else if (addr && addr->sa_family == AF_INET6) {
507                         struct sockaddr_in6 *sin6_addr = (void *) addr;
508
509                         char *buf = addrbuf;
510                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
511                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
512                         strcat(buf, "]");
513
514                         port = ntohs(sin6_addr->sin6_port);
515 #endif
516                 }
517                 loginfo("Connection from %s:%d", addrbuf, port);
518                 setenv("REMOTE_ADDR", addrbuf, 1);
519         }
520         else {
521                 unsetenv("REMOTE_ADDR");
522         }
523
524         alarm(init_timeout ? init_timeout : timeout);
525         pktlen = packet_read_line(0, line, sizeof(line));
526         alarm(0);
527
528         len = strlen(line);
529         if (pktlen != len)
530                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
531                         (int) pktlen - len,
532                         (int) pktlen - len, line + len + 1);
533         if (len && line[len-1] == '\n') {
534                 line[--len] = 0;
535                 pktlen--;
536         }
537
538         free(hostname);
539         free(canon_hostname);
540         free(ip_address);
541         free(tcp_port);
542         hostname = canon_hostname = ip_address = tcp_port = NULL;
543
544         if (len != pktlen)
545                 parse_host_arg(line + len + 1, pktlen - len - 1);
546
547         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
548                 struct daemon_service *s = &(daemon_service[i]);
549                 int namelen = strlen(s->name);
550                 if (!prefixcmp(line, "git-") &&
551                     !strncmp(s->name, line + 4, namelen) &&
552                     line[namelen + 4] == ' ') {
553                         /*
554                          * Note: The directory here is probably context sensitive,
555                          * and might depend on the actual service being performed.
556                          */
557                         return run_service(line + namelen + 5, s);
558                 }
559         }
560
561         logerror("Protocol error: '%s'", line);
562         return -1;
563 }
564
565 static int max_connections = 32;
566
567 static unsigned int live_children;
568
569 static struct child {
570         struct child *next;
571         pid_t pid;
572         struct sockaddr_storage address;
573 } *firstborn;
574
575 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
576 {
577         struct child *newborn, **cradle;
578
579         /*
580          * This must be xcalloc() -- we'll compare the whole sockaddr_storage
581          * but individual address may be shorter.
582          */
583         newborn = xcalloc(1, sizeof(*newborn));
584         live_children++;
585         newborn->pid = pid;
586         memcpy(&newborn->address, addr, addrlen);
587         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
588                 if (!memcmp(&(*cradle)->address, &newborn->address,
589                             sizeof(newborn->address)))
590                         break;
591         newborn->next = *cradle;
592         *cradle = newborn;
593 }
594
595 static void remove_child(pid_t pid)
596 {
597         struct child **cradle, *blanket;
598
599         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
600                 if (blanket->pid == pid) {
601                         *cradle = blanket->next;
602                         live_children--;
603                         free(blanket);
604                         break;
605                 }
606 }
607
608 /*
609  * This gets called if the number of connections grows
610  * past "max_connections".
611  *
612  * We kill the newest connection from a duplicate IP.
613  */
614 static void kill_some_child(void)
615 {
616         const struct child *blanket, *next;
617
618         if (!(blanket = firstborn))
619                 return;
620
621         for (; (next = blanket->next); blanket = next)
622                 if (!memcmp(&blanket->address, &next->address,
623                             sizeof(next->address))) {
624                         kill(blanket->pid, SIGTERM);
625                         break;
626                 }
627 }
628
629 static void check_dead_children(void)
630 {
631         int status;
632         pid_t pid;
633
634         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
635                 const char *dead = "";
636                 remove_child(pid);
637                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
638                         dead = " (with error)";
639                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
640         }
641 }
642
643 static void handle(int incoming, struct sockaddr *addr, int addrlen)
644 {
645         pid_t pid;
646
647         if (max_connections && live_children >= max_connections) {
648                 kill_some_child();
649                 sleep(1);  /* give it some time to die */
650                 check_dead_children();
651                 if (live_children >= max_connections) {
652                         close(incoming);
653                         logerror("Too many children, dropping connection");
654                         return;
655                 }
656         }
657
658         if ((pid = fork())) {
659                 close(incoming);
660                 if (pid < 0) {
661                         logerror("Couldn't fork %s", strerror(errno));
662                         return;
663                 }
664
665                 add_child(pid, addr, addrlen);
666                 return;
667         }
668
669         dup2(incoming, 0);
670         dup2(incoming, 1);
671         close(incoming);
672
673         exit(execute(addr));
674 }
675
676 static void child_handler(int signo)
677 {
678         /*
679          * Otherwise empty handler because systemcalls will get interrupted
680          * upon signal receipt
681          * SysV needs the handler to be rearmed
682          */
683         signal(SIGCHLD, child_handler);
684 }
685
686 static int set_reuse_addr(int sockfd)
687 {
688         int on = 1;
689
690         if (!reuseaddr)
691                 return 0;
692         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
693                           &on, sizeof(on));
694 }
695
696 #ifndef NO_IPV6
697
698 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
699 {
700         int socknum = 0, *socklist = NULL;
701         int maxfd = -1;
702         char pbuf[NI_MAXSERV];
703         struct addrinfo hints, *ai0, *ai;
704         int gai;
705         long flags;
706
707         sprintf(pbuf, "%d", listen_port);
708         memset(&hints, 0, sizeof(hints));
709         hints.ai_family = AF_UNSPEC;
710         hints.ai_socktype = SOCK_STREAM;
711         hints.ai_protocol = IPPROTO_TCP;
712         hints.ai_flags = AI_PASSIVE;
713
714         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
715         if (gai)
716                 die("getaddrinfo() failed: %s", gai_strerror(gai));
717
718         for (ai = ai0; ai; ai = ai->ai_next) {
719                 int sockfd;
720
721                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
722                 if (sockfd < 0)
723                         continue;
724                 if (sockfd >= FD_SETSIZE) {
725                         logerror("Socket descriptor too large");
726                         close(sockfd);
727                         continue;
728                 }
729
730 #ifdef IPV6_V6ONLY
731                 if (ai->ai_family == AF_INET6) {
732                         int on = 1;
733                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
734                                    &on, sizeof(on));
735                         /* Note: error is not fatal */
736                 }
737 #endif
738
739                 if (set_reuse_addr(sockfd)) {
740                         close(sockfd);
741                         continue;
742                 }
743
744                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
745                         close(sockfd);
746                         continue;       /* not fatal */
747                 }
748                 if (listen(sockfd, 5) < 0) {
749                         close(sockfd);
750                         continue;       /* not fatal */
751                 }
752
753                 flags = fcntl(sockfd, F_GETFD, 0);
754                 if (flags >= 0)
755                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
756
757                 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
758                 socklist[socknum++] = sockfd;
759
760                 if (maxfd < sockfd)
761                         maxfd = sockfd;
762         }
763
764         freeaddrinfo(ai0);
765
766         *socklist_p = socklist;
767         return socknum;
768 }
769
770 #else /* NO_IPV6 */
771
772 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
773 {
774         struct sockaddr_in sin;
775         int sockfd;
776         long flags;
777
778         memset(&sin, 0, sizeof sin);
779         sin.sin_family = AF_INET;
780         sin.sin_port = htons(listen_port);
781
782         if (listen_addr) {
783                 /* Well, host better be an IP address here. */
784                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
785                         return 0;
786         } else {
787                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
788         }
789
790         sockfd = socket(AF_INET, SOCK_STREAM, 0);
791         if (sockfd < 0)
792                 return 0;
793
794         if (set_reuse_addr(sockfd)) {
795                 close(sockfd);
796                 return 0;
797         }
798
799         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
800                 close(sockfd);
801                 return 0;
802         }
803
804         if (listen(sockfd, 5) < 0) {
805                 close(sockfd);
806                 return 0;
807         }
808
809         flags = fcntl(sockfd, F_GETFD, 0);
810         if (flags >= 0)
811                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
812
813         *socklist_p = xmalloc(sizeof(int));
814         **socklist_p = sockfd;
815         return 1;
816 }
817
818 #endif
819
820 static int service_loop(int socknum, int *socklist)
821 {
822         struct pollfd *pfd;
823         int i;
824
825         pfd = xcalloc(socknum, sizeof(struct pollfd));
826
827         for (i = 0; i < socknum; i++) {
828                 pfd[i].fd = socklist[i];
829                 pfd[i].events = POLLIN;
830         }
831
832         signal(SIGCHLD, child_handler);
833
834         for (;;) {
835                 int i;
836
837                 check_dead_children();
838
839                 if (poll(pfd, socknum, -1) < 0) {
840                         if (errno != EINTR) {
841                                 logerror("Poll failed, resuming: %s",
842                                       strerror(errno));
843                                 sleep(1);
844                         }
845                         continue;
846                 }
847
848                 for (i = 0; i < socknum; i++) {
849                         if (pfd[i].revents & POLLIN) {
850                                 struct sockaddr_storage ss;
851                                 unsigned int sslen = sizeof(ss);
852                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
853                                 if (incoming < 0) {
854                                         switch (errno) {
855                                         case EAGAIN:
856                                         case EINTR:
857                                         case ECONNABORTED:
858                                                 continue;
859                                         default:
860                                                 die_errno("accept returned");
861                                         }
862                                 }
863                                 handle(incoming, (struct sockaddr *)&ss, sslen);
864                         }
865                 }
866         }
867 }
868
869 /* if any standard file descriptor is missing open it to /dev/null */
870 static void sanitize_stdfds(void)
871 {
872         int fd = open("/dev/null", O_RDWR, 0);
873         while (fd != -1 && fd < 2)
874                 fd = dup(fd);
875         if (fd == -1)
876                 die_errno("open /dev/null or dup failed");
877         if (fd > 2)
878                 close(fd);
879 }
880
881 static void daemonize(void)
882 {
883         switch (fork()) {
884                 case 0:
885                         break;
886                 case -1:
887                         die_errno("fork failed");
888                 default:
889                         exit(0);
890         }
891         if (setsid() == -1)
892                 die_errno("setsid failed");
893         close(0);
894         close(1);
895         close(2);
896         sanitize_stdfds();
897 }
898
899 static void store_pid(const char *path)
900 {
901         FILE *f = fopen(path, "w");
902         if (!f)
903                 die_errno("cannot open pid file '%s'", path);
904         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
905                 die_errno("failed to write pid file '%s'", path);
906 }
907
908 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
909 {
910         int socknum, *socklist;
911
912         socknum = socksetup(listen_addr, listen_port, &socklist);
913         if (socknum == 0)
914                 die("unable to allocate any listen sockets on host %s port %u",
915                     listen_addr, listen_port);
916
917         if (pass && gid &&
918             (initgroups(pass->pw_name, gid) || setgid (gid) ||
919              setuid(pass->pw_uid)))
920                 die("cannot drop privileges");
921
922         return service_loop(socknum, socklist);
923 }
924
925 int main(int argc, char **argv)
926 {
927         int listen_port = 0;
928         char *listen_addr = NULL;
929         int inetd_mode = 0;
930         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
931         int detach = 0;
932         struct passwd *pass = NULL;
933         struct group *group;
934         gid_t gid = 0;
935         int i;
936
937         git_extract_argv0_path(argv[0]);
938
939         for (i = 1; i < argc; i++) {
940                 char *arg = argv[i];
941
942                 if (!prefixcmp(arg, "--listen=")) {
943                         listen_addr = xstrdup_tolower(arg + 9);
944                         continue;
945                 }
946                 if (!prefixcmp(arg, "--port=")) {
947                         char *end;
948                         unsigned long n;
949                         n = strtoul(arg+7, &end, 0);
950                         if (arg[7] && !*end) {
951                                 listen_port = n;
952                                 continue;
953                         }
954                 }
955                 if (!strcmp(arg, "--inetd")) {
956                         inetd_mode = 1;
957                         log_syslog = 1;
958                         continue;
959                 }
960                 if (!strcmp(arg, "--verbose")) {
961                         verbose = 1;
962                         continue;
963                 }
964                 if (!strcmp(arg, "--syslog")) {
965                         log_syslog = 1;
966                         continue;
967                 }
968                 if (!strcmp(arg, "--export-all")) {
969                         export_all_trees = 1;
970                         continue;
971                 }
972                 if (!prefixcmp(arg, "--timeout=")) {
973                         timeout = atoi(arg+10);
974                         continue;
975                 }
976                 if (!prefixcmp(arg, "--init-timeout=")) {
977                         init_timeout = atoi(arg+15);
978                         continue;
979                 }
980                 if (!prefixcmp(arg, "--max-connections=")) {
981                         max_connections = atoi(arg+18);
982                         if (max_connections < 0)
983                                 max_connections = 0;            /* unlimited */
984                         continue;
985                 }
986                 if (!strcmp(arg, "--strict-paths")) {
987                         strict_paths = 1;
988                         continue;
989                 }
990                 if (!prefixcmp(arg, "--base-path=")) {
991                         base_path = arg+12;
992                         continue;
993                 }
994                 if (!strcmp(arg, "--base-path-relaxed")) {
995                         base_path_relaxed = 1;
996                         continue;
997                 }
998                 if (!prefixcmp(arg, "--interpolated-path=")) {
999                         interpolated_path = arg+20;
1000                         continue;
1001                 }
1002                 if (!strcmp(arg, "--reuseaddr")) {
1003                         reuseaddr = 1;
1004                         continue;
1005                 }
1006                 if (!strcmp(arg, "--user-path")) {
1007                         user_path = "";
1008                         continue;
1009                 }
1010                 if (!prefixcmp(arg, "--user-path=")) {
1011                         user_path = arg + 12;
1012                         continue;
1013                 }
1014                 if (!prefixcmp(arg, "--pid-file=")) {
1015                         pid_file = arg + 11;
1016                         continue;
1017                 }
1018                 if (!strcmp(arg, "--detach")) {
1019                         detach = 1;
1020                         log_syslog = 1;
1021                         continue;
1022                 }
1023                 if (!prefixcmp(arg, "--user=")) {
1024                         user_name = arg + 7;
1025                         continue;
1026                 }
1027                 if (!prefixcmp(arg, "--group=")) {
1028                         group_name = arg + 8;
1029                         continue;
1030                 }
1031                 if (!prefixcmp(arg, "--enable=")) {
1032                         enable_service(arg + 9, 1);
1033                         continue;
1034                 }
1035                 if (!prefixcmp(arg, "--disable=")) {
1036                         enable_service(arg + 10, 0);
1037                         continue;
1038                 }
1039                 if (!prefixcmp(arg, "--allow-override=")) {
1040                         make_service_overridable(arg + 17, 1);
1041                         continue;
1042                 }
1043                 if (!prefixcmp(arg, "--forbid-override=")) {
1044                         make_service_overridable(arg + 18, 0);
1045                         continue;
1046                 }
1047                 if (!strcmp(arg, "--")) {
1048                         ok_paths = &argv[i+1];
1049                         break;
1050                 } else if (arg[0] != '-') {
1051                         ok_paths = &argv[i];
1052                         break;
1053                 }
1054
1055                 usage(daemon_usage);
1056         }
1057
1058         if (log_syslog) {
1059                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1060                 set_die_routine(daemon_die);
1061         } else
1062                 /* avoid splitting a message in the middle */
1063                 setvbuf(stderr, NULL, _IOLBF, 0);
1064
1065         if (inetd_mode && (group_name || user_name))
1066                 die("--user and --group are incompatible with --inetd");
1067
1068         if (inetd_mode && (listen_port || listen_addr))
1069                 die("--listen= and --port= are incompatible with --inetd");
1070         else if (listen_port == 0)
1071                 listen_port = DEFAULT_GIT_PORT;
1072
1073         if (group_name && !user_name)
1074                 die("--group supplied without --user");
1075
1076         if (user_name) {
1077                 pass = getpwnam(user_name);
1078                 if (!pass)
1079                         die("user not found - %s", user_name);
1080
1081                 if (!group_name)
1082                         gid = pass->pw_gid;
1083                 else {
1084                         group = getgrnam(group_name);
1085                         if (!group)
1086                                 die("group not found - %s", group_name);
1087
1088                         gid = group->gr_gid;
1089                 }
1090         }
1091
1092         if (strict_paths && (!ok_paths || !*ok_paths))
1093                 die("option --strict-paths requires a whitelist");
1094
1095         if (base_path && !is_directory(base_path))
1096                 die("base-path '%s' does not exist or is not a directory",
1097                     base_path);
1098
1099         if (inetd_mode) {
1100                 struct sockaddr_storage ss;
1101                 struct sockaddr *peer = (struct sockaddr *)&ss;
1102                 socklen_t slen = sizeof(ss);
1103
1104                 if (!freopen("/dev/null", "w", stderr))
1105                         die_errno("failed to redirect stderr to /dev/null");
1106
1107                 if (getpeername(0, peer, &slen))
1108                         peer = NULL;
1109
1110                 return execute(peer);
1111         }
1112
1113         if (detach) {
1114                 daemonize();
1115                 loginfo("Ready to rumble");
1116         }
1117         else
1118                 sanitize_stdfds();
1119
1120         if (pid_file)
1121                 store_pid(pid_file);
1122
1123         return serve(listen_addr, listen_port, pass, gid);
1124 }