Merge branch 'sh/rebase-i-p'
[git] / daemon.c
1 #include "cache.h"
2 #include "pkt-line.h"
3 #include "exec_cmd.h"
4 #include "interpolate.h"
5
6 #include <syslog.h>
7
8 #ifndef HOST_NAME_MAX
9 #define HOST_NAME_MAX 256
10 #endif
11
12 #ifndef NI_MAXSERV
13 #define NI_MAXSERV 32
14 #endif
15
16 static int log_syslog;
17 static int verbose;
18 static int reuseaddr;
19
20 static const char daemon_usage[] =
21 "git daemon [--verbose] [--syslog] [--export-all]\n"
22 "           [--timeout=n] [--init-timeout=n] [--max-connections=n]\n"
23 "           [--strict-paths] [--base-path=path] [--base-path-relaxed]\n"
24 "           [--user-path | --user-path=path]\n"
25 "           [--interpolated-path=path]\n"
26 "           [--reuseaddr] [--detach] [--pid-file=file]\n"
27 "           [--[enable|disable|allow-override|forbid-override]=service]\n"
28 "           [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
29 "                      [--user=user [--group=group]]\n"
30 "           [directory...]";
31
32 /* List of acceptable pathname prefixes */
33 static char **ok_paths;
34 static int strict_paths;
35
36 /* If this is set, git-daemon-export-ok is not required */
37 static int export_all_trees;
38
39 /* Take all paths relative to this one if non-NULL */
40 static char *base_path;
41 static char *interpolated_path;
42 static int base_path_relaxed;
43
44 /* Flag indicating client sent extra args. */
45 static int saw_extended_args;
46
47 /* If defined, ~user notation is allowed and the string is inserted
48  * after ~user/.  E.g. a request to git://host/~alice/frotz would
49  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
50  */
51 static const char *user_path;
52
53 /* Timeout, and initial timeout */
54 static unsigned int timeout;
55 static unsigned int init_timeout;
56
57 /*
58  * Static table for now.  Ugh.
59  * Feel free to make dynamic as needed.
60  */
61 #define INTERP_SLOT_HOST        (0)
62 #define INTERP_SLOT_CANON_HOST  (1)
63 #define INTERP_SLOT_IP          (2)
64 #define INTERP_SLOT_PORT        (3)
65 #define INTERP_SLOT_DIR         (4)
66 #define INTERP_SLOT_PERCENT     (5)
67
68 static struct interp interp_table[] = {
69         { "%H", 0},
70         { "%CH", 0},
71         { "%IP", 0},
72         { "%P", 0},
73         { "%D", 0},
74         { "%%", 0},
75 };
76
77
78 static void logreport(int priority, const char *err, va_list params)
79 {
80         if (log_syslog) {
81                 char buf[1024];
82                 vsnprintf(buf, sizeof(buf), err, params);
83                 syslog(priority, "%s", buf);
84         } else {
85                 /*
86                  * Since stderr is set to linebuffered mode, the
87                  * logging of different processes will not overlap
88                  */
89                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
90                 vfprintf(stderr, err, params);
91                 fputc('\n', stderr);
92         }
93 }
94
95 static void logerror(const char *err, ...)
96 {
97         va_list params;
98         va_start(params, err);
99         logreport(LOG_ERR, err, params);
100         va_end(params);
101 }
102
103 static void loginfo(const char *err, ...)
104 {
105         va_list params;
106         if (!verbose)
107                 return;
108         va_start(params, err);
109         logreport(LOG_INFO, err, params);
110         va_end(params);
111 }
112
113 static void NORETURN daemon_die(const char *err, va_list params)
114 {
115         logreport(LOG_ERR, err, params);
116         exit(1);
117 }
118
119 static int avoid_alias(char *p)
120 {
121         int sl, ndot;
122
123         /*
124          * This resurrects the belts and suspenders paranoia check by HPA
125          * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
126          * does not do getcwd() based path canonicalizations.
127          *
128          * sl becomes true immediately after seeing '/' and continues to
129          * be true as long as dots continue after that without intervening
130          * non-dot character.
131          */
132         if (!p || (*p != '/' && *p != '~'))
133                 return -1;
134         sl = 1; ndot = 0;
135         p++;
136
137         while (1) {
138                 char ch = *p++;
139                 if (sl) {
140                         if (ch == '.')
141                                 ndot++;
142                         else if (ch == '/') {
143                                 if (ndot < 3)
144                                         /* reject //, /./ and /../ */
145                                         return -1;
146                                 ndot = 0;
147                         }
148                         else if (ch == 0) {
149                                 if (0 < ndot && ndot < 3)
150                                         /* reject /.$ and /..$ */
151                                         return -1;
152                                 return 0;
153                         }
154                         else
155                                 sl = ndot = 0;
156                 }
157                 else if (ch == 0)
158                         return 0;
159                 else if (ch == '/') {
160                         sl = 1;
161                         ndot = 0;
162                 }
163         }
164 }
165
166 static char *path_ok(struct interp *itable)
167 {
168         static char rpath[PATH_MAX];
169         static char interp_path[PATH_MAX];
170         int retried_path = 0;
171         char *path;
172         char *dir;
173
174         dir = itable[INTERP_SLOT_DIR].value;
175
176         if (avoid_alias(dir)) {
177                 logerror("'%s': aliased", dir);
178                 return NULL;
179         }
180
181         if (*dir == '~') {
182                 if (!user_path) {
183                         logerror("'%s': User-path not allowed", dir);
184                         return NULL;
185                 }
186                 if (*user_path) {
187                         /* Got either "~alice" or "~alice/foo";
188                          * rewrite them to "~alice/%s" or
189                          * "~alice/%s/foo".
190                          */
191                         int namlen, restlen = strlen(dir);
192                         char *slash = strchr(dir, '/');
193                         if (!slash)
194                                 slash = dir + restlen;
195                         namlen = slash - dir;
196                         restlen -= namlen;
197                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
198                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
199                                  namlen, dir, user_path, restlen, slash);
200                         dir = rpath;
201                 }
202         }
203         else if (interpolated_path && saw_extended_args) {
204                 if (*dir != '/') {
205                         /* Allow only absolute */
206                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
207                         return NULL;
208                 }
209
210                 interpolate(interp_path, PATH_MAX, interpolated_path,
211                             interp_table, ARRAY_SIZE(interp_table));
212                 loginfo("Interpolated dir '%s'", interp_path);
213
214                 dir = interp_path;
215         }
216         else if (base_path) {
217                 if (*dir != '/') {
218                         /* Allow only absolute */
219                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
220                         return NULL;
221                 }
222                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
223                 dir = rpath;
224         }
225
226         do {
227                 path = enter_repo(dir, strict_paths);
228                 if (path)
229                         break;
230
231                 /*
232                  * if we fail and base_path_relaxed is enabled, try without
233                  * prefixing the base path
234                  */
235                 if (base_path && base_path_relaxed && !retried_path) {
236                         dir = itable[INTERP_SLOT_DIR].value;
237                         retried_path = 1;
238                         continue;
239                 }
240                 break;
241         } while (1);
242
243         if (!path) {
244                 logerror("'%s': unable to chdir or not a git archive", dir);
245                 return NULL;
246         }
247
248         if ( ok_paths && *ok_paths ) {
249                 char **pp;
250                 int pathlen = strlen(path);
251
252                 /* The validation is done on the paths after enter_repo
253                  * appends optional {.git,.git/.git} and friends, but
254                  * it does not use getcwd().  So if your /pub is
255                  * a symlink to /mnt/pub, you can whitelist /pub and
256                  * do not have to say /mnt/pub.
257                  * Do not say /pub/.
258                  */
259                 for ( pp = ok_paths ; *pp ; pp++ ) {
260                         int len = strlen(*pp);
261                         if (len <= pathlen &&
262                             !memcmp(*pp, path, len) &&
263                             (path[len] == '\0' ||
264                              (!strict_paths && path[len] == '/')))
265                                 return path;
266                 }
267         }
268         else {
269                 /* be backwards compatible */
270                 if (!strict_paths)
271                         return path;
272         }
273
274         logerror("'%s': not in whitelist", path);
275         return NULL;            /* Fallthrough. Deny by default */
276 }
277
278 typedef int (*daemon_service_fn)(void);
279 struct daemon_service {
280         const char *name;
281         const char *config_name;
282         daemon_service_fn fn;
283         int enabled;
284         int overridable;
285 };
286
287 static struct daemon_service *service_looking_at;
288 static int service_enabled;
289
290 static int git_daemon_config(const char *var, const char *value, void *cb)
291 {
292         if (!prefixcmp(var, "daemon.") &&
293             !strcmp(var + 7, service_looking_at->config_name)) {
294                 service_enabled = git_config_bool(var, value);
295                 return 0;
296         }
297
298         /* we are not interested in parsing any other configuration here */
299         return 0;
300 }
301
302 static int run_service(struct interp *itable, struct daemon_service *service)
303 {
304         const char *path;
305         int enabled = service->enabled;
306
307         loginfo("Request %s for '%s'",
308                 service->name,
309                 itable[INTERP_SLOT_DIR].value);
310
311         if (!enabled && !service->overridable) {
312                 logerror("'%s': service not enabled.", service->name);
313                 errno = EACCES;
314                 return -1;
315         }
316
317         if (!(path = path_ok(itable)))
318                 return -1;
319
320         /*
321          * Security on the cheap.
322          *
323          * We want a readable HEAD, usable "objects" directory, and
324          * a "git-daemon-export-ok" flag that says that the other side
325          * is ok with us doing this.
326          *
327          * path_ok() uses enter_repo() and does whitelist checking.
328          * We only need to make sure the repository is exported.
329          */
330
331         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
332                 logerror("'%s': repository not exported.", path);
333                 errno = EACCES;
334                 return -1;
335         }
336
337         if (service->overridable) {
338                 service_looking_at = service;
339                 service_enabled = -1;
340                 git_config(git_daemon_config, NULL);
341                 if (0 <= service_enabled)
342                         enabled = service_enabled;
343         }
344         if (!enabled) {
345                 logerror("'%s': service not enabled for '%s'",
346                          service->name, path);
347                 errno = EACCES;
348                 return -1;
349         }
350
351         /*
352          * We'll ignore SIGTERM from now on, we have a
353          * good client.
354          */
355         signal(SIGTERM, SIG_IGN);
356
357         return service->fn();
358 }
359
360 static int upload_pack(void)
361 {
362         /* Timeout as string */
363         char timeout_buf[64];
364
365         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
366
367         /* git-upload-pack only ever reads stuff, so this is safe */
368         execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
369         return -1;
370 }
371
372 static int upload_archive(void)
373 {
374         execl_git_cmd("upload-archive", ".", NULL);
375         return -1;
376 }
377
378 static int receive_pack(void)
379 {
380         execl_git_cmd("receive-pack", ".", NULL);
381         return -1;
382 }
383
384 static struct daemon_service daemon_service[] = {
385         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
386         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
387         { "receive-pack", "receivepack", receive_pack, 0, 1 },
388 };
389
390 static void enable_service(const char *name, int ena)
391 {
392         int i;
393         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
394                 if (!strcmp(daemon_service[i].name, name)) {
395                         daemon_service[i].enabled = ena;
396                         return;
397                 }
398         }
399         die("No such service %s", name);
400 }
401
402 static void make_service_overridable(const char *name, int ena)
403 {
404         int i;
405         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
406                 if (!strcmp(daemon_service[i].name, name)) {
407                         daemon_service[i].overridable = ena;
408                         return;
409                 }
410         }
411         die("No such service %s", name);
412 }
413
414 /*
415  * Separate the "extra args" information as supplied by the client connection.
416  * Any resulting data is squirreled away in the given interpolation table.
417  */
418 static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
419 {
420         char *val;
421         int vallen;
422         char *end = extra_args + buflen;
423
424         while (extra_args < end && *extra_args) {
425                 saw_extended_args = 1;
426                 if (strncasecmp("host=", extra_args, 5) == 0) {
427                         val = extra_args + 5;
428                         vallen = strlen(val) + 1;
429                         if (*val) {
430                                 /* Split <host>:<port> at colon. */
431                                 char *host = val;
432                                 char *port = strrchr(host, ':');
433                                 if (port) {
434                                         *port = 0;
435                                         port++;
436                                         interp_set_entry(table, INTERP_SLOT_PORT, port);
437                                 }
438                                 interp_set_entry(table, INTERP_SLOT_HOST, host);
439                         }
440
441                         /* On to the next one */
442                         extra_args = val + vallen;
443                 }
444         }
445 }
446
447 static void fill_in_extra_table_entries(struct interp *itable)
448 {
449         char *hp;
450
451         /*
452          * Replace literal host with lowercase-ized hostname.
453          */
454         hp = interp_table[INTERP_SLOT_HOST].value;
455         if (!hp)
456                 return;
457         for ( ; *hp; hp++)
458                 *hp = tolower(*hp);
459
460         /*
461          * Locate canonical hostname and its IP address.
462          */
463 #ifndef NO_IPV6
464         {
465                 struct addrinfo hints;
466                 struct addrinfo *ai, *ai0;
467                 int gai;
468                 static char addrbuf[HOST_NAME_MAX + 1];
469
470                 memset(&hints, 0, sizeof(hints));
471                 hints.ai_flags = AI_CANONNAME;
472
473                 gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
474                 if (!gai) {
475                         for (ai = ai0; ai; ai = ai->ai_next) {
476                                 struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
477
478                                 inet_ntop(AF_INET, &sin_addr->sin_addr,
479                                           addrbuf, sizeof(addrbuf));
480                                 interp_set_entry(interp_table,
481                                                  INTERP_SLOT_CANON_HOST, ai->ai_canonname);
482                                 interp_set_entry(interp_table,
483                                                  INTERP_SLOT_IP, addrbuf);
484                                 break;
485                         }
486                         freeaddrinfo(ai0);
487                 }
488         }
489 #else
490         {
491                 struct hostent *hent;
492                 struct sockaddr_in sa;
493                 char **ap;
494                 static char addrbuf[HOST_NAME_MAX + 1];
495
496                 hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
497
498                 ap = hent->h_addr_list;
499                 memset(&sa, 0, sizeof sa);
500                 sa.sin_family = hent->h_addrtype;
501                 sa.sin_port = htons(0);
502                 memcpy(&sa.sin_addr, *ap, hent->h_length);
503
504                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
505                           addrbuf, sizeof(addrbuf));
506
507                 interp_set_entry(interp_table, INTERP_SLOT_CANON_HOST, hent->h_name);
508                 interp_set_entry(interp_table, INTERP_SLOT_IP, addrbuf);
509         }
510 #endif
511 }
512
513
514 static int execute(struct sockaddr *addr)
515 {
516         static char line[1000];
517         int pktlen, len, i;
518
519         if (addr) {
520                 char addrbuf[256] = "";
521                 int port = -1;
522
523                 if (addr->sa_family == AF_INET) {
524                         struct sockaddr_in *sin_addr = (void *) addr;
525                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
526                         port = ntohs(sin_addr->sin_port);
527 #ifndef NO_IPV6
528                 } else if (addr && addr->sa_family == AF_INET6) {
529                         struct sockaddr_in6 *sin6_addr = (void *) addr;
530
531                         char *buf = addrbuf;
532                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
533                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
534                         strcat(buf, "]");
535
536                         port = ntohs(sin6_addr->sin6_port);
537 #endif
538                 }
539                 loginfo("Connection from %s:%d", addrbuf, port);
540                 setenv("REMOTE_ADDR", addrbuf, 1);
541         }
542         else {
543                 unsetenv("REMOTE_ADDR");
544         }
545
546         alarm(init_timeout ? init_timeout : timeout);
547         pktlen = packet_read_line(0, line, sizeof(line));
548         alarm(0);
549
550         len = strlen(line);
551         if (pktlen != len)
552                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
553                         (int) pktlen - len,
554                         (int) pktlen - len, line + len + 1);
555         if (len && line[len-1] == '\n') {
556                 line[--len] = 0;
557                 pktlen--;
558         }
559
560         /*
561          * Initialize the path interpolation table for this connection.
562          */
563         interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
564         interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
565
566         if (len != pktlen) {
567             parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
568             fill_in_extra_table_entries(interp_table);
569         }
570
571         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
572                 struct daemon_service *s = &(daemon_service[i]);
573                 int namelen = strlen(s->name);
574                 if (!prefixcmp(line, "git-") &&
575                     !strncmp(s->name, line + 4, namelen) &&
576                     line[namelen + 4] == ' ') {
577                         /*
578                          * Note: The directory here is probably context sensitive,
579                          * and might depend on the actual service being performed.
580                          */
581                         interp_set_entry(interp_table,
582                                          INTERP_SLOT_DIR, line + namelen + 5);
583                         return run_service(interp_table, s);
584                 }
585         }
586
587         logerror("Protocol error: '%s'", line);
588         return -1;
589 }
590
591 static int max_connections = 32;
592
593 static unsigned int live_children;
594
595 static struct child {
596         struct child *next;
597         pid_t pid;
598         struct sockaddr_storage address;
599 } *firstborn;
600
601 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
602 {
603         struct child *newborn, **cradle;
604
605         /*
606          * This must be xcalloc() -- we'll compare the whole sockaddr_storage
607          * but individual address may be shorter.
608          */
609         newborn = xcalloc(1, sizeof(*newborn));
610         live_children++;
611         newborn->pid = pid;
612         memcpy(&newborn->address, addr, addrlen);
613         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
614                 if (!memcmp(&(*cradle)->address, &newborn->address,
615                             sizeof(newborn->address)))
616                         break;
617         newborn->next = *cradle;
618         *cradle = newborn;
619 }
620
621 static void remove_child(pid_t pid)
622 {
623         struct child **cradle, *blanket;
624
625         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
626                 if (blanket->pid == pid) {
627                         *cradle = blanket->next;
628                         live_children--;
629                         free(blanket);
630                         break;
631                 }
632 }
633
634 /*
635  * This gets called if the number of connections grows
636  * past "max_connections".
637  *
638  * We kill the newest connection from a duplicate IP.
639  */
640 static void kill_some_child(void)
641 {
642         const struct child *blanket, *next;
643
644         if (!(blanket = firstborn))
645                 return;
646
647         for (; (next = blanket->next); blanket = next)
648                 if (!memcmp(&blanket->address, &next->address,
649                             sizeof(next->address))) {
650                         kill(blanket->pid, SIGTERM);
651                         break;
652                 }
653 }
654
655 static void check_dead_children(void)
656 {
657         int status;
658         pid_t pid;
659
660         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
661                 const char *dead = "";
662                 remove_child(pid);
663                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
664                         dead = " (with error)";
665                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
666         }
667 }
668
669 static void handle(int incoming, struct sockaddr *addr, int addrlen)
670 {
671         pid_t pid;
672
673         if (max_connections && live_children >= max_connections) {
674                 kill_some_child();
675                 sleep(1);  /* give it some time to die */
676                 check_dead_children();
677                 if (live_children >= max_connections) {
678                         close(incoming);
679                         logerror("Too many children, dropping connection");
680                         return;
681                 }
682         }
683
684         if ((pid = fork())) {
685                 close(incoming);
686                 if (pid < 0) {
687                         logerror("Couldn't fork %s", strerror(errno));
688                         return;
689                 }
690
691                 add_child(pid, addr, addrlen);
692                 return;
693         }
694
695         dup2(incoming, 0);
696         dup2(incoming, 1);
697         close(incoming);
698
699         exit(execute(addr));
700 }
701
702 static void child_handler(int signo)
703 {
704         /*
705          * Otherwise empty handler because systemcalls will get interrupted
706          * upon signal receipt
707          * SysV needs the handler to be rearmed
708          */
709         signal(SIGCHLD, child_handler);
710 }
711
712 static int set_reuse_addr(int sockfd)
713 {
714         int on = 1;
715
716         if (!reuseaddr)
717                 return 0;
718         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
719                           &on, sizeof(on));
720 }
721
722 #ifndef NO_IPV6
723
724 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
725 {
726         int socknum = 0, *socklist = NULL;
727         int maxfd = -1;
728         char pbuf[NI_MAXSERV];
729         struct addrinfo hints, *ai0, *ai;
730         int gai;
731         long flags;
732
733         sprintf(pbuf, "%d", listen_port);
734         memset(&hints, 0, sizeof(hints));
735         hints.ai_family = AF_UNSPEC;
736         hints.ai_socktype = SOCK_STREAM;
737         hints.ai_protocol = IPPROTO_TCP;
738         hints.ai_flags = AI_PASSIVE;
739
740         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
741         if (gai)
742                 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
743
744         for (ai = ai0; ai; ai = ai->ai_next) {
745                 int sockfd;
746
747                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
748                 if (sockfd < 0)
749                         continue;
750                 if (sockfd >= FD_SETSIZE) {
751                         logerror("Socket descriptor too large");
752                         close(sockfd);
753                         continue;
754                 }
755
756 #ifdef IPV6_V6ONLY
757                 if (ai->ai_family == AF_INET6) {
758                         int on = 1;
759                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
760                                    &on, sizeof(on));
761                         /* Note: error is not fatal */
762                 }
763 #endif
764
765                 if (set_reuse_addr(sockfd)) {
766                         close(sockfd);
767                         continue;
768                 }
769
770                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
771                         close(sockfd);
772                         continue;       /* not fatal */
773                 }
774                 if (listen(sockfd, 5) < 0) {
775                         close(sockfd);
776                         continue;       /* not fatal */
777                 }
778
779                 flags = fcntl(sockfd, F_GETFD, 0);
780                 if (flags >= 0)
781                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
782
783                 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
784                 socklist[socknum++] = sockfd;
785
786                 if (maxfd < sockfd)
787                         maxfd = sockfd;
788         }
789
790         freeaddrinfo(ai0);
791
792         *socklist_p = socklist;
793         return socknum;
794 }
795
796 #else /* NO_IPV6 */
797
798 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
799 {
800         struct sockaddr_in sin;
801         int sockfd;
802         long flags;
803
804         memset(&sin, 0, sizeof sin);
805         sin.sin_family = AF_INET;
806         sin.sin_port = htons(listen_port);
807
808         if (listen_addr) {
809                 /* Well, host better be an IP address here. */
810                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
811                         return 0;
812         } else {
813                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
814         }
815
816         sockfd = socket(AF_INET, SOCK_STREAM, 0);
817         if (sockfd < 0)
818                 return 0;
819
820         if (set_reuse_addr(sockfd)) {
821                 close(sockfd);
822                 return 0;
823         }
824
825         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
826                 close(sockfd);
827                 return 0;
828         }
829
830         if (listen(sockfd, 5) < 0) {
831                 close(sockfd);
832                 return 0;
833         }
834
835         flags = fcntl(sockfd, F_GETFD, 0);
836         if (flags >= 0)
837                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
838
839         *socklist_p = xmalloc(sizeof(int));
840         **socklist_p = sockfd;
841         return 1;
842 }
843
844 #endif
845
846 static int service_loop(int socknum, int *socklist)
847 {
848         struct pollfd *pfd;
849         int i;
850
851         pfd = xcalloc(socknum, sizeof(struct pollfd));
852
853         for (i = 0; i < socknum; i++) {
854                 pfd[i].fd = socklist[i];
855                 pfd[i].events = POLLIN;
856         }
857
858         signal(SIGCHLD, child_handler);
859
860         for (;;) {
861                 int i;
862
863                 check_dead_children();
864
865                 if (poll(pfd, socknum, -1) < 0) {
866                         if (errno != EINTR) {
867                                 logerror("Poll failed, resuming: %s",
868                                       strerror(errno));
869                                 sleep(1);
870                         }
871                         continue;
872                 }
873
874                 for (i = 0; i < socknum; i++) {
875                         if (pfd[i].revents & POLLIN) {
876                                 struct sockaddr_storage ss;
877                                 unsigned int sslen = sizeof(ss);
878                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
879                                 if (incoming < 0) {
880                                         switch (errno) {
881                                         case EAGAIN:
882                                         case EINTR:
883                                         case ECONNABORTED:
884                                                 continue;
885                                         default:
886                                                 die("accept returned %s", strerror(errno));
887                                         }
888                                 }
889                                 handle(incoming, (struct sockaddr *)&ss, sslen);
890                         }
891                 }
892         }
893 }
894
895 /* if any standard file descriptor is missing open it to /dev/null */
896 static void sanitize_stdfds(void)
897 {
898         int fd = open("/dev/null", O_RDWR, 0);
899         while (fd != -1 && fd < 2)
900                 fd = dup(fd);
901         if (fd == -1)
902                 die("open /dev/null or dup failed: %s", strerror(errno));
903         if (fd > 2)
904                 close(fd);
905 }
906
907 static void daemonize(void)
908 {
909         switch (fork()) {
910                 case 0:
911                         break;
912                 case -1:
913                         die("fork failed: %s", strerror(errno));
914                 default:
915                         exit(0);
916         }
917         if (setsid() == -1)
918                 die("setsid failed: %s", strerror(errno));
919         close(0);
920         close(1);
921         close(2);
922         sanitize_stdfds();
923 }
924
925 static void store_pid(const char *path)
926 {
927         FILE *f = fopen(path, "w");
928         if (!f)
929                 die("cannot open pid file %s: %s", path, strerror(errno));
930         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
931                 die("failed to write pid file %s: %s", path, strerror(errno));
932 }
933
934 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
935 {
936         int socknum, *socklist;
937
938         socknum = socksetup(listen_addr, listen_port, &socklist);
939         if (socknum == 0)
940                 die("unable to allocate any listen sockets on host %s port %u",
941                     listen_addr, listen_port);
942
943         if (pass && gid &&
944             (initgroups(pass->pw_name, gid) || setgid (gid) ||
945              setuid(pass->pw_uid)))
946                 die("cannot drop privileges");
947
948         return service_loop(socknum, socklist);
949 }
950
951 int main(int argc, char **argv)
952 {
953         int listen_port = 0;
954         char *listen_addr = NULL;
955         int inetd_mode = 0;
956         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
957         int detach = 0;
958         struct passwd *pass = NULL;
959         struct group *group;
960         gid_t gid = 0;
961         int i;
962
963         for (i = 1; i < argc; i++) {
964                 char *arg = argv[i];
965
966                 if (!prefixcmp(arg, "--listen=")) {
967                     char *p = arg + 9;
968                     char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
969                     while (*p)
970                         *ph++ = tolower(*p++);
971                     *ph = 0;
972                     continue;
973                 }
974                 if (!prefixcmp(arg, "--port=")) {
975                         char *end;
976                         unsigned long n;
977                         n = strtoul(arg+7, &end, 0);
978                         if (arg[7] && !*end) {
979                                 listen_port = n;
980                                 continue;
981                         }
982                 }
983                 if (!strcmp(arg, "--inetd")) {
984                         inetd_mode = 1;
985                         log_syslog = 1;
986                         continue;
987                 }
988                 if (!strcmp(arg, "--verbose")) {
989                         verbose = 1;
990                         continue;
991                 }
992                 if (!strcmp(arg, "--syslog")) {
993                         log_syslog = 1;
994                         continue;
995                 }
996                 if (!strcmp(arg, "--export-all")) {
997                         export_all_trees = 1;
998                         continue;
999                 }
1000                 if (!prefixcmp(arg, "--timeout=")) {
1001                         timeout = atoi(arg+10);
1002                         continue;
1003                 }
1004                 if (!prefixcmp(arg, "--init-timeout=")) {
1005                         init_timeout = atoi(arg+15);
1006                         continue;
1007                 }
1008                 if (!prefixcmp(arg, "--max-connections=")) {
1009                         max_connections = atoi(arg+18);
1010                         if (max_connections < 0)
1011                                 max_connections = 0;            /* unlimited */
1012                         continue;
1013                 }
1014                 if (!strcmp(arg, "--strict-paths")) {
1015                         strict_paths = 1;
1016                         continue;
1017                 }
1018                 if (!prefixcmp(arg, "--base-path=")) {
1019                         base_path = arg+12;
1020                         continue;
1021                 }
1022                 if (!strcmp(arg, "--base-path-relaxed")) {
1023                         base_path_relaxed = 1;
1024                         continue;
1025                 }
1026                 if (!prefixcmp(arg, "--interpolated-path=")) {
1027                         interpolated_path = arg+20;
1028                         continue;
1029                 }
1030                 if (!strcmp(arg, "--reuseaddr")) {
1031                         reuseaddr = 1;
1032                         continue;
1033                 }
1034                 if (!strcmp(arg, "--user-path")) {
1035                         user_path = "";
1036                         continue;
1037                 }
1038                 if (!prefixcmp(arg, "--user-path=")) {
1039                         user_path = arg + 12;
1040                         continue;
1041                 }
1042                 if (!prefixcmp(arg, "--pid-file=")) {
1043                         pid_file = arg + 11;
1044                         continue;
1045                 }
1046                 if (!strcmp(arg, "--detach")) {
1047                         detach = 1;
1048                         log_syslog = 1;
1049                         continue;
1050                 }
1051                 if (!prefixcmp(arg, "--user=")) {
1052                         user_name = arg + 7;
1053                         continue;
1054                 }
1055                 if (!prefixcmp(arg, "--group=")) {
1056                         group_name = arg + 8;
1057                         continue;
1058                 }
1059                 if (!prefixcmp(arg, "--enable=")) {
1060                         enable_service(arg + 9, 1);
1061                         continue;
1062                 }
1063                 if (!prefixcmp(arg, "--disable=")) {
1064                         enable_service(arg + 10, 0);
1065                         continue;
1066                 }
1067                 if (!prefixcmp(arg, "--allow-override=")) {
1068                         make_service_overridable(arg + 17, 1);
1069                         continue;
1070                 }
1071                 if (!prefixcmp(arg, "--forbid-override=")) {
1072                         make_service_overridable(arg + 18, 0);
1073                         continue;
1074                 }
1075                 if (!strcmp(arg, "--")) {
1076                         ok_paths = &argv[i+1];
1077                         break;
1078                 } else if (arg[0] != '-') {
1079                         ok_paths = &argv[i];
1080                         break;
1081                 }
1082
1083                 usage(daemon_usage);
1084         }
1085
1086         if (log_syslog) {
1087                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1088                 set_die_routine(daemon_die);
1089         } else
1090                 /* avoid splitting a message in the middle */
1091                 setvbuf(stderr, NULL, _IOLBF, 0);
1092
1093         if (inetd_mode && (group_name || user_name))
1094                 die("--user and --group are incompatible with --inetd");
1095
1096         if (inetd_mode && (listen_port || listen_addr))
1097                 die("--listen= and --port= are incompatible with --inetd");
1098         else if (listen_port == 0)
1099                 listen_port = DEFAULT_GIT_PORT;
1100
1101         if (group_name && !user_name)
1102                 die("--group supplied without --user");
1103
1104         if (user_name) {
1105                 pass = getpwnam(user_name);
1106                 if (!pass)
1107                         die("user not found - %s", user_name);
1108
1109                 if (!group_name)
1110                         gid = pass->pw_gid;
1111                 else {
1112                         group = getgrnam(group_name);
1113                         if (!group)
1114                                 die("group not found - %s", group_name);
1115
1116                         gid = group->gr_gid;
1117                 }
1118         }
1119
1120         if (strict_paths && (!ok_paths || !*ok_paths))
1121                 die("option --strict-paths requires a whitelist");
1122
1123         if (base_path && !is_directory(base_path))
1124                 die("base-path '%s' does not exist or is not a directory",
1125                     base_path);
1126
1127         if (inetd_mode) {
1128                 struct sockaddr_storage ss;
1129                 struct sockaddr *peer = (struct sockaddr *)&ss;
1130                 socklen_t slen = sizeof(ss);
1131
1132                 freopen("/dev/null", "w", stderr);
1133
1134                 if (getpeername(0, peer, &slen))
1135                         peer = NULL;
1136
1137                 return execute(peer);
1138         }
1139
1140         if (detach) {
1141                 daemonize();
1142                 loginfo("Ready to rumble");
1143         }
1144         else
1145                 sanitize_stdfds();
1146
1147         if (pid_file)
1148                 store_pid(pid_file);
1149
1150         return serve(listen_addr, listen_port, pass, gid);
1151 }