Merge branch 'maint'
[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 static void logerror(const char *err, ...)
81 {
82         va_list params;
83         va_start(params, err);
84         logreport(LOG_ERR, err, params);
85         va_end(params);
86 }
87
88 static void loginfo(const char *err, ...)
89 {
90         va_list params;
91         if (!verbose)
92                 return;
93         va_start(params, err);
94         logreport(LOG_INFO, err, params);
95         va_end(params);
96 }
97
98 static void NORETURN daemon_die(const char *err, va_list params)
99 {
100         logreport(LOG_ERR, err, params);
101         exit(1);
102 }
103
104 static int avoid_alias(char *p)
105 {
106         int sl, ndot;
107
108         /*
109          * This resurrects the belts and suspenders paranoia check by HPA
110          * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
111          * does not do getcwd() based path canonicalizations.
112          *
113          * sl becomes true immediately after seeing '/' and continues to
114          * be true as long as dots continue after that without intervening
115          * non-dot character.
116          */
117         if (!p || (*p != '/' && *p != '~'))
118                 return -1;
119         sl = 1; ndot = 0;
120         p++;
121
122         while (1) {
123                 char ch = *p++;
124                 if (sl) {
125                         if (ch == '.')
126                                 ndot++;
127                         else if (ch == '/') {
128                                 if (ndot < 3)
129                                         /* reject //, /./ and /../ */
130                                         return -1;
131                                 ndot = 0;
132                         }
133                         else if (ch == 0) {
134                                 if (0 < ndot && ndot < 3)
135                                         /* reject /.$ and /..$ */
136                                         return -1;
137                                 return 0;
138                         }
139                         else
140                                 sl = ndot = 0;
141                 }
142                 else if (ch == 0)
143                         return 0;
144                 else if (ch == '/') {
145                         sl = 1;
146                         ndot = 0;
147                 }
148         }
149 }
150
151 static char *path_ok(char *directory)
152 {
153         static char rpath[PATH_MAX];
154         static char interp_path[PATH_MAX];
155         char *path;
156         char *dir;
157
158         dir = directory;
159
160         if (avoid_alias(dir)) {
161                 logerror("'%s': aliased", dir);
162                 return NULL;
163         }
164
165         if (*dir == '~') {
166                 if (!user_path) {
167                         logerror("'%s': User-path not allowed", dir);
168                         return NULL;
169                 }
170                 if (*user_path) {
171                         /* Got either "~alice" or "~alice/foo";
172                          * rewrite them to "~alice/%s" or
173                          * "~alice/%s/foo".
174                          */
175                         int namlen, restlen = strlen(dir);
176                         char *slash = strchr(dir, '/');
177                         if (!slash)
178                                 slash = dir + restlen;
179                         namlen = slash - dir;
180                         restlen -= namlen;
181                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
182                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
183                                  namlen, dir, user_path, restlen, slash);
184                         dir = rpath;
185                 }
186         }
187         else if (interpolated_path && saw_extended_args) {
188                 struct strbuf expanded_path = STRBUF_INIT;
189                 struct strbuf_expand_dict_entry dict[] = {
190                         { "H", hostname },
191                         { "CH", canon_hostname },
192                         { "IP", ip_address },
193                         { "P", tcp_port },
194                         { "D", directory },
195                         { "%", "%" },
196                         { NULL }
197                 };
198
199                 if (*dir != '/') {
200                         /* Allow only absolute */
201                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
202                         return NULL;
203                 }
204
205                 strbuf_expand(&expanded_path, interpolated_path,
206                                 strbuf_expand_dict_cb, &dict);
207                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
208                 strbuf_release(&expanded_path);
209                 loginfo("Interpolated dir '%s'", interp_path);
210
211                 dir = interp_path;
212         }
213         else if (base_path) {
214                 if (*dir != '/') {
215                         /* Allow only absolute */
216                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
217                         return NULL;
218                 }
219                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
220                 dir = rpath;
221         }
222
223         path = enter_repo(dir, strict_paths);
224         if (!path && base_path && base_path_relaxed) {
225                 /*
226                  * if we fail and base_path_relaxed is enabled, try without
227                  * prefixing the base path
228                  */
229                 dir = directory;
230                 path = enter_repo(dir, strict_paths);
231         }
232
233         if (!path) {
234                 logerror("'%s' does not appear to be a git repository", dir);
235                 return NULL;
236         }
237
238         if ( ok_paths && *ok_paths ) {
239                 char **pp;
240                 int pathlen = strlen(path);
241
242                 /* The validation is done on the paths after enter_repo
243                  * appends optional {.git,.git/.git} and friends, but
244                  * it does not use getcwd().  So if your /pub is
245                  * a symlink to /mnt/pub, you can whitelist /pub and
246                  * do not have to say /mnt/pub.
247                  * Do not say /pub/.
248                  */
249                 for ( pp = ok_paths ; *pp ; pp++ ) {
250                         int len = strlen(*pp);
251                         if (len <= pathlen &&
252                             !memcmp(*pp, path, len) &&
253                             (path[len] == '\0' ||
254                              (!strict_paths && path[len] == '/')))
255                                 return path;
256                 }
257         }
258         else {
259                 /* be backwards compatible */
260                 if (!strict_paths)
261                         return path;
262         }
263
264         logerror("'%s': not in whitelist", path);
265         return NULL;            /* Fallthrough. Deny by default */
266 }
267
268 typedef int (*daemon_service_fn)(void);
269 struct daemon_service {
270         const char *name;
271         const char *config_name;
272         daemon_service_fn fn;
273         int enabled;
274         int overridable;
275 };
276
277 static struct daemon_service *service_looking_at;
278 static int service_enabled;
279
280 static int git_daemon_config(const char *var, const char *value, void *cb)
281 {
282         if (!prefixcmp(var, "daemon.") &&
283             !strcmp(var + 7, service_looking_at->config_name)) {
284                 service_enabled = git_config_bool(var, value);
285                 return 0;
286         }
287
288         /* we are not interested in parsing any other configuration here */
289         return 0;
290 }
291
292 static int run_service(char *dir, struct daemon_service *service)
293 {
294         const char *path;
295         int enabled = service->enabled;
296
297         loginfo("Request %s for '%s'", service->name, dir);
298
299         if (!enabled && !service->overridable) {
300                 logerror("'%s': service not enabled.", service->name);
301                 errno = EACCES;
302                 return -1;
303         }
304
305         if (!(path = path_ok(dir)))
306                 return -1;
307
308         /*
309          * Security on the cheap.
310          *
311          * We want a readable HEAD, usable "objects" directory, and
312          * a "git-daemon-export-ok" flag that says that the other side
313          * is ok with us doing this.
314          *
315          * path_ok() uses enter_repo() and does whitelist checking.
316          * We only need to make sure the repository is exported.
317          */
318
319         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
320                 logerror("'%s': repository not exported.", path);
321                 errno = EACCES;
322                 return -1;
323         }
324
325         if (service->overridable) {
326                 service_looking_at = service;
327                 service_enabled = -1;
328                 git_config(git_daemon_config, NULL);
329                 if (0 <= service_enabled)
330                         enabled = service_enabled;
331         }
332         if (!enabled) {
333                 logerror("'%s': service not enabled for '%s'",
334                          service->name, path);
335                 errno = EACCES;
336                 return -1;
337         }
338
339         /*
340          * We'll ignore SIGTERM from now on, we have a
341          * good client.
342          */
343         signal(SIGTERM, SIG_IGN);
344
345         return service->fn();
346 }
347
348 static void copy_to_log(int fd)
349 {
350         struct strbuf line = STRBUF_INIT;
351         FILE *fp;
352
353         fp = fdopen(fd, "r");
354         if (fp == NULL) {
355                 logerror("fdopen of error channel failed");
356                 close(fd);
357                 return;
358         }
359
360         while (strbuf_getline(&line, fp, '\n') != EOF) {
361                 logerror("%s", line.buf);
362                 strbuf_setlen(&line, 0);
363         }
364
365         strbuf_release(&line);
366         fclose(fp);
367 }
368
369 static int run_service_command(const char **argv)
370 {
371         struct child_process cld;
372
373         memset(&cld, 0, sizeof(cld));
374         cld.argv = argv;
375         cld.git_cmd = 1;
376         cld.err = -1;
377         if (start_command(&cld))
378                 return -1;
379
380         close(0);
381         close(1);
382
383         copy_to_log(cld.err);
384
385         return finish_command(&cld);
386 }
387
388 static int upload_pack(void)
389 {
390         /* Timeout as string */
391         char timeout_buf[64];
392         const char *argv[] = { "upload-pack", "--strict", timeout_buf, ".", NULL };
393
394         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
395         return run_service_command(argv);
396 }
397
398 static int upload_archive(void)
399 {
400         static const char *argv[] = { "upload-archive", ".", NULL };
401         return run_service_command(argv);
402 }
403
404 static int receive_pack(void)
405 {
406         static const char *argv[] = { "receive-pack", ".", NULL };
407         return run_service_command(argv);
408 }
409
410 static struct daemon_service daemon_service[] = {
411         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
412         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
413         { "receive-pack", "receivepack", receive_pack, 0, 1 },
414 };
415
416 static void enable_service(const char *name, int ena)
417 {
418         int i;
419         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
420                 if (!strcmp(daemon_service[i].name, name)) {
421                         daemon_service[i].enabled = ena;
422                         return;
423                 }
424         }
425         die("No such service %s", name);
426 }
427
428 static void make_service_overridable(const char *name, int ena)
429 {
430         int i;
431         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
432                 if (!strcmp(daemon_service[i].name, name)) {
433                         daemon_service[i].overridable = ena;
434                         return;
435                 }
436         }
437         die("No such service %s", name);
438 }
439
440 static char *xstrdup_tolower(const char *str)
441 {
442         char *p, *dup = xstrdup(str);
443         for (p = dup; *p; p++)
444                 *p = tolower(*p);
445         return dup;
446 }
447
448 /*
449  * Read the host as supplied by the client connection.
450  */
451 static void parse_host_arg(char *extra_args, int buflen)
452 {
453         char *val;
454         int vallen;
455         char *end = extra_args + buflen;
456
457         if (extra_args < end && *extra_args) {
458                 saw_extended_args = 1;
459                 if (strncasecmp("host=", extra_args, 5) == 0) {
460                         val = extra_args + 5;
461                         vallen = strlen(val) + 1;
462                         if (*val) {
463                                 /* Split <host>:<port> at colon. */
464                                 char *host = val;
465                                 char *port = strrchr(host, ':');
466                                 if (port) {
467                                         *port = 0;
468                                         port++;
469                                         free(tcp_port);
470                                         tcp_port = xstrdup(port);
471                                 }
472                                 free(hostname);
473                                 hostname = xstrdup_tolower(host);
474                         }
475
476                         /* On to the next one */
477                         extra_args = val + vallen;
478                 }
479                 if (extra_args < end && *extra_args)
480                         die("Invalid request");
481         }
482
483         /*
484          * Locate canonical hostname and its IP address.
485          */
486         if (hostname) {
487 #ifndef NO_IPV6
488                 struct addrinfo hints;
489                 struct addrinfo *ai;
490                 int gai;
491                 static char addrbuf[HOST_NAME_MAX + 1];
492
493                 memset(&hints, 0, sizeof(hints));
494                 hints.ai_flags = AI_CANONNAME;
495
496                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
497                 if (!gai) {
498                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
499
500                         inet_ntop(AF_INET, &sin_addr->sin_addr,
501                                   addrbuf, sizeof(addrbuf));
502                         free(ip_address);
503                         ip_address = xstrdup(addrbuf);
504
505                         free(canon_hostname);
506                         canon_hostname = xstrdup(ai->ai_canonname ?
507                                                  ai->ai_canonname : ip_address);
508
509                         freeaddrinfo(ai);
510                 }
511 #else
512                 struct hostent *hent;
513                 struct sockaddr_in sa;
514                 char **ap;
515                 static char addrbuf[HOST_NAME_MAX + 1];
516
517                 hent = gethostbyname(hostname);
518
519                 ap = hent->h_addr_list;
520                 memset(&sa, 0, sizeof sa);
521                 sa.sin_family = hent->h_addrtype;
522                 sa.sin_port = htons(0);
523                 memcpy(&sa.sin_addr, *ap, hent->h_length);
524
525                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
526                           addrbuf, sizeof(addrbuf));
527
528                 free(canon_hostname);
529                 canon_hostname = xstrdup(hent->h_name);
530                 free(ip_address);
531                 ip_address = xstrdup(addrbuf);
532 #endif
533         }
534 }
535
536
537 static int execute(struct sockaddr *addr)
538 {
539         static char line[1000];
540         int pktlen, len, i;
541
542         if (addr) {
543                 char addrbuf[256] = "";
544                 int port = -1;
545
546                 if (addr->sa_family == AF_INET) {
547                         struct sockaddr_in *sin_addr = (void *) addr;
548                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
549                         port = ntohs(sin_addr->sin_port);
550 #ifndef NO_IPV6
551                 } else if (addr && addr->sa_family == AF_INET6) {
552                         struct sockaddr_in6 *sin6_addr = (void *) addr;
553
554                         char *buf = addrbuf;
555                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
556                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
557                         strcat(buf, "]");
558
559                         port = ntohs(sin6_addr->sin6_port);
560 #endif
561                 }
562                 loginfo("Connection from %s:%d", addrbuf, port);
563                 setenv("REMOTE_ADDR", addrbuf, 1);
564         }
565         else {
566                 unsetenv("REMOTE_ADDR");
567         }
568
569         alarm(init_timeout ? init_timeout : timeout);
570         pktlen = packet_read_line(0, line, sizeof(line));
571         alarm(0);
572
573         len = strlen(line);
574         if (pktlen != len)
575                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
576                         (int) pktlen - len,
577                         (int) pktlen - len, line + len + 1);
578         if (len && line[len-1] == '\n') {
579                 line[--len] = 0;
580                 pktlen--;
581         }
582
583         free(hostname);
584         free(canon_hostname);
585         free(ip_address);
586         free(tcp_port);
587         hostname = canon_hostname = ip_address = tcp_port = NULL;
588
589         if (len != pktlen)
590                 parse_host_arg(line + len + 1, pktlen - len - 1);
591
592         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
593                 struct daemon_service *s = &(daemon_service[i]);
594                 int namelen = strlen(s->name);
595                 if (!prefixcmp(line, "git-") &&
596                     !strncmp(s->name, line + 4, namelen) &&
597                     line[namelen + 4] == ' ') {
598                         /*
599                          * Note: The directory here is probably context sensitive,
600                          * and might depend on the actual service being performed.
601                          */
602                         return run_service(line + namelen + 5, s);
603                 }
604         }
605
606         logerror("Protocol error: '%s'", line);
607         return -1;
608 }
609
610 static int max_connections = 32;
611
612 static unsigned int live_children;
613
614 static struct child {
615         struct child *next;
616         pid_t pid;
617         struct sockaddr_storage address;
618 } *firstborn;
619
620 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
621 {
622         struct child *newborn, **cradle;
623
624         /*
625          * This must be xcalloc() -- we'll compare the whole sockaddr_storage
626          * but individual address may be shorter.
627          */
628         newborn = xcalloc(1, sizeof(*newborn));
629         live_children++;
630         newborn->pid = pid;
631         memcpy(&newborn->address, addr, addrlen);
632         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
633                 if (!memcmp(&(*cradle)->address, &newborn->address,
634                             sizeof(newborn->address)))
635                         break;
636         newborn->next = *cradle;
637         *cradle = newborn;
638 }
639
640 static void remove_child(pid_t pid)
641 {
642         struct child **cradle, *blanket;
643
644         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
645                 if (blanket->pid == pid) {
646                         *cradle = blanket->next;
647                         live_children--;
648                         free(blanket);
649                         break;
650                 }
651 }
652
653 /*
654  * This gets called if the number of connections grows
655  * past "max_connections".
656  *
657  * We kill the newest connection from a duplicate IP.
658  */
659 static void kill_some_child(void)
660 {
661         const struct child *blanket, *next;
662
663         if (!(blanket = firstborn))
664                 return;
665
666         for (; (next = blanket->next); blanket = next)
667                 if (!memcmp(&blanket->address, &next->address,
668                             sizeof(next->address))) {
669                         kill(blanket->pid, SIGTERM);
670                         break;
671                 }
672 }
673
674 static void check_dead_children(void)
675 {
676         int status;
677         pid_t pid;
678
679         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
680                 const char *dead = "";
681                 remove_child(pid);
682                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
683                         dead = " (with error)";
684                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
685         }
686 }
687
688 static void handle(int incoming, struct sockaddr *addr, int addrlen)
689 {
690         pid_t pid;
691
692         if (max_connections && live_children >= max_connections) {
693                 kill_some_child();
694                 sleep(1);  /* give it some time to die */
695                 check_dead_children();
696                 if (live_children >= max_connections) {
697                         close(incoming);
698                         logerror("Too many children, dropping connection");
699                         return;
700                 }
701         }
702
703         if ((pid = fork())) {
704                 close(incoming);
705                 if (pid < 0) {
706                         logerror("Couldn't fork %s", strerror(errno));
707                         return;
708                 }
709
710                 add_child(pid, addr, addrlen);
711                 return;
712         }
713
714         dup2(incoming, 0);
715         dup2(incoming, 1);
716         close(incoming);
717
718         exit(execute(addr));
719 }
720
721 static void child_handler(int signo)
722 {
723         /*
724          * Otherwise empty handler because systemcalls will get interrupted
725          * upon signal receipt
726          * SysV needs the handler to be rearmed
727          */
728         signal(SIGCHLD, child_handler);
729 }
730
731 static int set_reuse_addr(int sockfd)
732 {
733         int on = 1;
734
735         if (!reuseaddr)
736                 return 0;
737         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
738                           &on, sizeof(on));
739 }
740
741 #ifndef NO_IPV6
742
743 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
744 {
745         int socknum = 0, *socklist = NULL;
746         int maxfd = -1;
747         char pbuf[NI_MAXSERV];
748         struct addrinfo hints, *ai0, *ai;
749         int gai;
750         long flags;
751
752         sprintf(pbuf, "%d", listen_port);
753         memset(&hints, 0, sizeof(hints));
754         hints.ai_family = AF_UNSPEC;
755         hints.ai_socktype = SOCK_STREAM;
756         hints.ai_protocol = IPPROTO_TCP;
757         hints.ai_flags = AI_PASSIVE;
758
759         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
760         if (gai)
761                 die("getaddrinfo() failed: %s", gai_strerror(gai));
762
763         for (ai = ai0; ai; ai = ai->ai_next) {
764                 int sockfd;
765
766                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
767                 if (sockfd < 0)
768                         continue;
769                 if (sockfd >= FD_SETSIZE) {
770                         logerror("Socket descriptor too large");
771                         close(sockfd);
772                         continue;
773                 }
774
775 #ifdef IPV6_V6ONLY
776                 if (ai->ai_family == AF_INET6) {
777                         int on = 1;
778                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
779                                    &on, sizeof(on));
780                         /* Note: error is not fatal */
781                 }
782 #endif
783
784                 if (set_reuse_addr(sockfd)) {
785                         close(sockfd);
786                         continue;
787                 }
788
789                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
790                         close(sockfd);
791                         continue;       /* not fatal */
792                 }
793                 if (listen(sockfd, 5) < 0) {
794                         close(sockfd);
795                         continue;       /* not fatal */
796                 }
797
798                 flags = fcntl(sockfd, F_GETFD, 0);
799                 if (flags >= 0)
800                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
801
802                 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
803                 socklist[socknum++] = sockfd;
804
805                 if (maxfd < sockfd)
806                         maxfd = sockfd;
807         }
808
809         freeaddrinfo(ai0);
810
811         *socklist_p = socklist;
812         return socknum;
813 }
814
815 #else /* NO_IPV6 */
816
817 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
818 {
819         struct sockaddr_in sin;
820         int sockfd;
821         long flags;
822
823         memset(&sin, 0, sizeof sin);
824         sin.sin_family = AF_INET;
825         sin.sin_port = htons(listen_port);
826
827         if (listen_addr) {
828                 /* Well, host better be an IP address here. */
829                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
830                         return 0;
831         } else {
832                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
833         }
834
835         sockfd = socket(AF_INET, SOCK_STREAM, 0);
836         if (sockfd < 0)
837                 return 0;
838
839         if (set_reuse_addr(sockfd)) {
840                 close(sockfd);
841                 return 0;
842         }
843
844         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
845                 close(sockfd);
846                 return 0;
847         }
848
849         if (listen(sockfd, 5) < 0) {
850                 close(sockfd);
851                 return 0;
852         }
853
854         flags = fcntl(sockfd, F_GETFD, 0);
855         if (flags >= 0)
856                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
857
858         *socklist_p = xmalloc(sizeof(int));
859         **socklist_p = sockfd;
860         return 1;
861 }
862
863 #endif
864
865 static int service_loop(int socknum, int *socklist)
866 {
867         struct pollfd *pfd;
868         int i;
869
870         pfd = xcalloc(socknum, sizeof(struct pollfd));
871
872         for (i = 0; i < socknum; i++) {
873                 pfd[i].fd = socklist[i];
874                 pfd[i].events = POLLIN;
875         }
876
877         signal(SIGCHLD, child_handler);
878
879         for (;;) {
880                 int i;
881
882                 check_dead_children();
883
884                 if (poll(pfd, socknum, -1) < 0) {
885                         if (errno != EINTR) {
886                                 logerror("Poll failed, resuming: %s",
887                                       strerror(errno));
888                                 sleep(1);
889                         }
890                         continue;
891                 }
892
893                 for (i = 0; i < socknum; i++) {
894                         if (pfd[i].revents & POLLIN) {
895                                 struct sockaddr_storage ss;
896                                 unsigned int sslen = sizeof(ss);
897                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
898                                 if (incoming < 0) {
899                                         switch (errno) {
900                                         case EAGAIN:
901                                         case EINTR:
902                                         case ECONNABORTED:
903                                                 continue;
904                                         default:
905                                                 die_errno("accept returned");
906                                         }
907                                 }
908                                 handle(incoming, (struct sockaddr *)&ss, sslen);
909                         }
910                 }
911         }
912 }
913
914 /* if any standard file descriptor is missing open it to /dev/null */
915 static void sanitize_stdfds(void)
916 {
917         int fd = open("/dev/null", O_RDWR, 0);
918         while (fd != -1 && fd < 2)
919                 fd = dup(fd);
920         if (fd == -1)
921                 die_errno("open /dev/null or dup failed");
922         if (fd > 2)
923                 close(fd);
924 }
925
926 static void daemonize(void)
927 {
928         switch (fork()) {
929                 case 0:
930                         break;
931                 case -1:
932                         die_errno("fork failed");
933                 default:
934                         exit(0);
935         }
936         if (setsid() == -1)
937                 die_errno("setsid failed");
938         close(0);
939         close(1);
940         close(2);
941         sanitize_stdfds();
942 }
943
944 static void store_pid(const char *path)
945 {
946         FILE *f = fopen(path, "w");
947         if (!f)
948                 die_errno("cannot open pid file '%s'", path);
949         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
950                 die_errno("failed to write pid file '%s'", path);
951 }
952
953 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
954 {
955         int socknum, *socklist;
956
957         socknum = socksetup(listen_addr, listen_port, &socklist);
958         if (socknum == 0)
959                 die("unable to allocate any listen sockets on host %s port %u",
960                     listen_addr, listen_port);
961
962         if (pass && gid &&
963             (initgroups(pass->pw_name, gid) || setgid (gid) ||
964              setuid(pass->pw_uid)))
965                 die("cannot drop privileges");
966
967         return service_loop(socknum, socklist);
968 }
969
970 int main(int argc, char **argv)
971 {
972         int listen_port = 0;
973         char *listen_addr = NULL;
974         int inetd_mode = 0;
975         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
976         int detach = 0;
977         struct passwd *pass = NULL;
978         struct group *group;
979         gid_t gid = 0;
980         int i;
981
982         git_extract_argv0_path(argv[0]);
983
984         for (i = 1; i < argc; i++) {
985                 char *arg = argv[i];
986
987                 if (!prefixcmp(arg, "--listen=")) {
988                         listen_addr = xstrdup_tolower(arg + 9);
989                         continue;
990                 }
991                 if (!prefixcmp(arg, "--port=")) {
992                         char *end;
993                         unsigned long n;
994                         n = strtoul(arg+7, &end, 0);
995                         if (arg[7] && !*end) {
996                                 listen_port = n;
997                                 continue;
998                         }
999                 }
1000                 if (!strcmp(arg, "--inetd")) {
1001                         inetd_mode = 1;
1002                         log_syslog = 1;
1003                         continue;
1004                 }
1005                 if (!strcmp(arg, "--verbose")) {
1006                         verbose = 1;
1007                         continue;
1008                 }
1009                 if (!strcmp(arg, "--syslog")) {
1010                         log_syslog = 1;
1011                         continue;
1012                 }
1013                 if (!strcmp(arg, "--export-all")) {
1014                         export_all_trees = 1;
1015                         continue;
1016                 }
1017                 if (!prefixcmp(arg, "--timeout=")) {
1018                         timeout = atoi(arg+10);
1019                         continue;
1020                 }
1021                 if (!prefixcmp(arg, "--init-timeout=")) {
1022                         init_timeout = atoi(arg+15);
1023                         continue;
1024                 }
1025                 if (!prefixcmp(arg, "--max-connections=")) {
1026                         max_connections = atoi(arg+18);
1027                         if (max_connections < 0)
1028                                 max_connections = 0;            /* unlimited */
1029                         continue;
1030                 }
1031                 if (!strcmp(arg, "--strict-paths")) {
1032                         strict_paths = 1;
1033                         continue;
1034                 }
1035                 if (!prefixcmp(arg, "--base-path=")) {
1036                         base_path = arg+12;
1037                         continue;
1038                 }
1039                 if (!strcmp(arg, "--base-path-relaxed")) {
1040                         base_path_relaxed = 1;
1041                         continue;
1042                 }
1043                 if (!prefixcmp(arg, "--interpolated-path=")) {
1044                         interpolated_path = arg+20;
1045                         continue;
1046                 }
1047                 if (!strcmp(arg, "--reuseaddr")) {
1048                         reuseaddr = 1;
1049                         continue;
1050                 }
1051                 if (!strcmp(arg, "--user-path")) {
1052                         user_path = "";
1053                         continue;
1054                 }
1055                 if (!prefixcmp(arg, "--user-path=")) {
1056                         user_path = arg + 12;
1057                         continue;
1058                 }
1059                 if (!prefixcmp(arg, "--pid-file=")) {
1060                         pid_file = arg + 11;
1061                         continue;
1062                 }
1063                 if (!strcmp(arg, "--detach")) {
1064                         detach = 1;
1065                         log_syslog = 1;
1066                         continue;
1067                 }
1068                 if (!prefixcmp(arg, "--user=")) {
1069                         user_name = arg + 7;
1070                         continue;
1071                 }
1072                 if (!prefixcmp(arg, "--group=")) {
1073                         group_name = arg + 8;
1074                         continue;
1075                 }
1076                 if (!prefixcmp(arg, "--enable=")) {
1077                         enable_service(arg + 9, 1);
1078                         continue;
1079                 }
1080                 if (!prefixcmp(arg, "--disable=")) {
1081                         enable_service(arg + 10, 0);
1082                         continue;
1083                 }
1084                 if (!prefixcmp(arg, "--allow-override=")) {
1085                         make_service_overridable(arg + 17, 1);
1086                         continue;
1087                 }
1088                 if (!prefixcmp(arg, "--forbid-override=")) {
1089                         make_service_overridable(arg + 18, 0);
1090                         continue;
1091                 }
1092                 if (!strcmp(arg, "--")) {
1093                         ok_paths = &argv[i+1];
1094                         break;
1095                 } else if (arg[0] != '-') {
1096                         ok_paths = &argv[i];
1097                         break;
1098                 }
1099
1100                 usage(daemon_usage);
1101         }
1102
1103         if (log_syslog) {
1104                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1105                 set_die_routine(daemon_die);
1106         } else
1107                 /* avoid splitting a message in the middle */
1108                 setvbuf(stderr, NULL, _IOLBF, 0);
1109
1110         if (inetd_mode && (group_name || user_name))
1111                 die("--user and --group are incompatible with --inetd");
1112
1113         if (inetd_mode && (listen_port || listen_addr))
1114                 die("--listen= and --port= are incompatible with --inetd");
1115         else if (listen_port == 0)
1116                 listen_port = DEFAULT_GIT_PORT;
1117
1118         if (group_name && !user_name)
1119                 die("--group supplied without --user");
1120
1121         if (user_name) {
1122                 pass = getpwnam(user_name);
1123                 if (!pass)
1124                         die("user not found - %s", user_name);
1125
1126                 if (!group_name)
1127                         gid = pass->pw_gid;
1128                 else {
1129                         group = getgrnam(group_name);
1130                         if (!group)
1131                                 die("group not found - %s", group_name);
1132
1133                         gid = group->gr_gid;
1134                 }
1135         }
1136
1137         if (strict_paths && (!ok_paths || !*ok_paths))
1138                 die("option --strict-paths requires a whitelist");
1139
1140         if (base_path && !is_directory(base_path))
1141                 die("base-path '%s' does not exist or is not a directory",
1142                     base_path);
1143
1144         if (inetd_mode) {
1145                 struct sockaddr_storage ss;
1146                 struct sockaddr *peer = (struct sockaddr *)&ss;
1147                 socklen_t slen = sizeof(ss);
1148
1149                 if (!freopen("/dev/null", "w", stderr))
1150                         die_errno("failed to redirect stderr to /dev/null");
1151
1152                 if (getpeername(0, peer, &slen))
1153                         peer = NULL;
1154
1155                 return execute(peer);
1156         }
1157
1158         if (detach) {
1159                 daemonize();
1160                 loginfo("Ready to rumble");
1161         }
1162         else
1163                 sanitize_stdfds();
1164
1165         if (pid_file)
1166                 store_pid(pid_file);
1167
1168         return serve(listen_addr, listen_port, pass, gid);
1169 }