Merge branch 'jl/add-p-reverse-message'
[git] / daemon.c
1 #include "cache.h"
2 #include "pkt-line.h"
3 #include "exec_cmd.h"
4 #include "run-command.h"
5 #include "strbuf.h"
6 #include "string-list.h"
7
8 #ifndef HOST_NAME_MAX
9 #define HOST_NAME_MAX 256
10 #endif
11
12 #ifndef NI_MAXSERV
13 #define NI_MAXSERV 32
14 #endif
15
16 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] [--pid-file=<file>]\n"
27 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
28 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
29 "                      [--detach] [--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 static char *hostname;
58 static char *canon_hostname;
59 static char *ip_address;
60 static char *tcp_port;
61
62 static void logreport(int priority, const char *err, va_list params)
63 {
64         if (log_syslog) {
65                 char buf[1024];
66                 vsnprintf(buf, sizeof(buf), err, params);
67                 syslog(priority, "%s", buf);
68         } else {
69                 /*
70                  * Since stderr is set to buffered mode, the
71                  * logging of different processes will not overlap
72                  * unless they overflow the (rather big) buffers.
73                  */
74                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
75                 vfprintf(stderr, err, params);
76                 fputc('\n', stderr);
77                 fflush(stderr);
78         }
79 }
80
81 __attribute__((format (printf, 1, 2)))
82 static void logerror(const char *err, ...)
83 {
84         va_list params;
85         va_start(params, err);
86         logreport(LOG_ERR, err, params);
87         va_end(params);
88 }
89
90 __attribute__((format (printf, 1, 2)))
91 static void loginfo(const char *err, ...)
92 {
93         va_list params;
94         if (!verbose)
95                 return;
96         va_start(params, err);
97         logreport(LOG_INFO, err, params);
98         va_end(params);
99 }
100
101 static void NORETURN daemon_die(const char *err, va_list params)
102 {
103         logreport(LOG_ERR, err, params);
104         exit(1);
105 }
106
107 static char *path_ok(char *directory)
108 {
109         static char rpath[PATH_MAX];
110         static char interp_path[PATH_MAX];
111         char *path;
112         char *dir;
113
114         dir = directory;
115
116         if (daemon_avoid_alias(dir)) {
117                 logerror("'%s': aliased", dir);
118                 return NULL;
119         }
120
121         if (*dir == '~') {
122                 if (!user_path) {
123                         logerror("'%s': User-path not allowed", dir);
124                         return NULL;
125                 }
126                 if (*user_path) {
127                         /* Got either "~alice" or "~alice/foo";
128                          * rewrite them to "~alice/%s" or
129                          * "~alice/%s/foo".
130                          */
131                         int namlen, restlen = strlen(dir);
132                         char *slash = strchr(dir, '/');
133                         if (!slash)
134                                 slash = dir + restlen;
135                         namlen = slash - dir;
136                         restlen -= namlen;
137                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
138                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
139                                  namlen, dir, user_path, restlen, slash);
140                         dir = rpath;
141                 }
142         }
143         else if (interpolated_path && saw_extended_args) {
144                 struct strbuf expanded_path = STRBUF_INIT;
145                 struct strbuf_expand_dict_entry dict[6];
146
147                 dict[0].placeholder = "H"; dict[0].value = hostname;
148                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
149                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
150                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
151                 dict[4].placeholder = "D"; dict[4].value = directory;
152                 dict[5].placeholder = NULL; dict[5].value = NULL;
153                 if (*dir != '/') {
154                         /* Allow only absolute */
155                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
156                         return NULL;
157                 }
158
159                 strbuf_expand(&expanded_path, interpolated_path,
160                                 strbuf_expand_dict_cb, &dict);
161                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
162                 strbuf_release(&expanded_path);
163                 loginfo("Interpolated dir '%s'", interp_path);
164
165                 dir = interp_path;
166         }
167         else if (base_path) {
168                 if (*dir != '/') {
169                         /* Allow only absolute */
170                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
171                         return NULL;
172                 }
173                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
174                 dir = rpath;
175         }
176
177         path = enter_repo(dir, strict_paths);
178         if (!path && base_path && base_path_relaxed) {
179                 /*
180                  * if we fail and base_path_relaxed is enabled, try without
181                  * prefixing the base path
182                  */
183                 dir = directory;
184                 path = enter_repo(dir, strict_paths);
185         }
186
187         if (!path) {
188                 logerror("'%s' does not appear to be a git repository", dir);
189                 return NULL;
190         }
191
192         if ( ok_paths && *ok_paths ) {
193                 char **pp;
194                 int pathlen = strlen(path);
195
196                 /* The validation is done on the paths after enter_repo
197                  * appends optional {.git,.git/.git} and friends, but
198                  * it does not use getcwd().  So if your /pub is
199                  * a symlink to /mnt/pub, you can whitelist /pub and
200                  * do not have to say /mnt/pub.
201                  * Do not say /pub/.
202                  */
203                 for ( pp = ok_paths ; *pp ; pp++ ) {
204                         int len = strlen(*pp);
205                         if (len <= pathlen &&
206                             !memcmp(*pp, path, len) &&
207                             (path[len] == '\0' ||
208                              (!strict_paths && path[len] == '/')))
209                                 return path;
210                 }
211         }
212         else {
213                 /* be backwards compatible */
214                 if (!strict_paths)
215                         return path;
216         }
217
218         logerror("'%s': not in whitelist", path);
219         return NULL;            /* Fallthrough. Deny by default */
220 }
221
222 typedef int (*daemon_service_fn)(void);
223 struct daemon_service {
224         const char *name;
225         const char *config_name;
226         daemon_service_fn fn;
227         int enabled;
228         int overridable;
229 };
230
231 static struct daemon_service *service_looking_at;
232 static int service_enabled;
233
234 static int git_daemon_config(const char *var, const char *value, void *cb)
235 {
236         if (!prefixcmp(var, "daemon.") &&
237             !strcmp(var + 7, service_looking_at->config_name)) {
238                 service_enabled = git_config_bool(var, value);
239                 return 0;
240         }
241
242         /* we are not interested in parsing any other configuration here */
243         return 0;
244 }
245
246 static int run_service(char *dir, struct daemon_service *service)
247 {
248         const char *path;
249         int enabled = service->enabled;
250
251         loginfo("Request %s for '%s'", service->name, dir);
252
253         if (!enabled && !service->overridable) {
254                 logerror("'%s': service not enabled.", service->name);
255                 errno = EACCES;
256                 return -1;
257         }
258
259         if (!(path = path_ok(dir)))
260                 return -1;
261
262         /*
263          * Security on the cheap.
264          *
265          * We want a readable HEAD, usable "objects" directory, and
266          * a "git-daemon-export-ok" flag that says that the other side
267          * is ok with us doing this.
268          *
269          * path_ok() uses enter_repo() and does whitelist checking.
270          * We only need to make sure the repository is exported.
271          */
272
273         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
274                 logerror("'%s': repository not exported.", path);
275                 errno = EACCES;
276                 return -1;
277         }
278
279         if (service->overridable) {
280                 service_looking_at = service;
281                 service_enabled = -1;
282                 git_config(git_daemon_config, NULL);
283                 if (0 <= service_enabled)
284                         enabled = service_enabled;
285         }
286         if (!enabled) {
287                 logerror("'%s': service not enabled for '%s'",
288                          service->name, path);
289                 errno = EACCES;
290                 return -1;
291         }
292
293         /*
294          * We'll ignore SIGTERM from now on, we have a
295          * good client.
296          */
297         signal(SIGTERM, SIG_IGN);
298
299         return service->fn();
300 }
301
302 static void copy_to_log(int fd)
303 {
304         struct strbuf line = STRBUF_INIT;
305         FILE *fp;
306
307         fp = fdopen(fd, "r");
308         if (fp == NULL) {
309                 logerror("fdopen of error channel failed");
310                 close(fd);
311                 return;
312         }
313
314         while (strbuf_getline(&line, fp, '\n') != EOF) {
315                 logerror("%s", line.buf);
316                 strbuf_setlen(&line, 0);
317         }
318
319         strbuf_release(&line);
320         fclose(fp);
321 }
322
323 static int run_service_command(const char **argv)
324 {
325         struct child_process cld;
326
327         memset(&cld, 0, sizeof(cld));
328         cld.argv = argv;
329         cld.git_cmd = 1;
330         cld.err = -1;
331         if (start_command(&cld))
332                 return -1;
333
334         close(0);
335         close(1);
336
337         copy_to_log(cld.err);
338
339         return finish_command(&cld);
340 }
341
342 static int upload_pack(void)
343 {
344         /* Timeout as string */
345         char timeout_buf[64];
346         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
347
348         argv[2] = timeout_buf;
349
350         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
351         return run_service_command(argv);
352 }
353
354 static int upload_archive(void)
355 {
356         static const char *argv[] = { "upload-archive", ".", NULL };
357         return run_service_command(argv);
358 }
359
360 static int receive_pack(void)
361 {
362         static const char *argv[] = { "receive-pack", ".", NULL };
363         return run_service_command(argv);
364 }
365
366 static struct daemon_service daemon_service[] = {
367         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
368         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
369         { "receive-pack", "receivepack", receive_pack, 0, 1 },
370 };
371
372 static void enable_service(const char *name, int ena)
373 {
374         int i;
375         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
376                 if (!strcmp(daemon_service[i].name, name)) {
377                         daemon_service[i].enabled = ena;
378                         return;
379                 }
380         }
381         die("No such service %s", name);
382 }
383
384 static void make_service_overridable(const char *name, int ena)
385 {
386         int i;
387         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
388                 if (!strcmp(daemon_service[i].name, name)) {
389                         daemon_service[i].overridable = ena;
390                         return;
391                 }
392         }
393         die("No such service %s", name);
394 }
395
396 static char *xstrdup_tolower(const char *str)
397 {
398         char *p, *dup = xstrdup(str);
399         for (p = dup; *p; p++)
400                 *p = tolower(*p);
401         return dup;
402 }
403
404 static void parse_host_and_port(char *hostport, char **host,
405         char **port)
406 {
407         if (*hostport == '[') {
408                 char *end;
409
410                 end = strchr(hostport, ']');
411                 if (!end)
412                         die("Invalid request ('[' without ']')");
413                 *end = '\0';
414                 *host = hostport + 1;
415                 if (!end[1])
416                         *port = NULL;
417                 else if (end[1] == ':')
418                         *port = end + 2;
419                 else
420                         die("Garbage after end of host part");
421         } else {
422                 *host = hostport;
423                 *port = strrchr(hostport, ':');
424                 if (*port) {
425                         **port = '\0';
426                         ++*port;
427                 }
428         }
429 }
430
431 /*
432  * Read the host as supplied by the client connection.
433  */
434 static void parse_host_arg(char *extra_args, int buflen)
435 {
436         char *val;
437         int vallen;
438         char *end = extra_args + buflen;
439
440         if (extra_args < end && *extra_args) {
441                 saw_extended_args = 1;
442                 if (strncasecmp("host=", extra_args, 5) == 0) {
443                         val = extra_args + 5;
444                         vallen = strlen(val) + 1;
445                         if (*val) {
446                                 /* Split <host>:<port> at colon. */
447                                 char *host;
448                                 char *port;
449                                 parse_host_and_port(val, &host, &port);
450                                 if (port) {
451                                         free(tcp_port);
452                                         tcp_port = xstrdup(port);
453                                 }
454                                 free(hostname);
455                                 hostname = xstrdup_tolower(host);
456                         }
457
458                         /* On to the next one */
459                         extra_args = val + vallen;
460                 }
461                 if (extra_args < end && *extra_args)
462                         die("Invalid request");
463         }
464
465         /*
466          * Locate canonical hostname and its IP address.
467          */
468         if (hostname) {
469 #ifndef NO_IPV6
470                 struct addrinfo hints;
471                 struct addrinfo *ai;
472                 int gai;
473                 static char addrbuf[HOST_NAME_MAX + 1];
474
475                 memset(&hints, 0, sizeof(hints));
476                 hints.ai_flags = AI_CANONNAME;
477
478                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
479                 if (!gai) {
480                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
481
482                         inet_ntop(AF_INET, &sin_addr->sin_addr,
483                                   addrbuf, sizeof(addrbuf));
484                         free(ip_address);
485                         ip_address = xstrdup(addrbuf);
486
487                         free(canon_hostname);
488                         canon_hostname = xstrdup(ai->ai_canonname ?
489                                                  ai->ai_canonname : ip_address);
490
491                         freeaddrinfo(ai);
492                 }
493 #else
494                 struct hostent *hent;
495                 struct sockaddr_in sa;
496                 char **ap;
497                 static char addrbuf[HOST_NAME_MAX + 1];
498
499                 hent = gethostbyname(hostname);
500
501                 ap = hent->h_addr_list;
502                 memset(&sa, 0, sizeof sa);
503                 sa.sin_family = hent->h_addrtype;
504                 sa.sin_port = htons(0);
505                 memcpy(&sa.sin_addr, *ap, hent->h_length);
506
507                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
508                           addrbuf, sizeof(addrbuf));
509
510                 free(canon_hostname);
511                 canon_hostname = xstrdup(hent->h_name);
512                 free(ip_address);
513                 ip_address = xstrdup(addrbuf);
514 #endif
515         }
516 }
517
518
519 static int execute(void)
520 {
521         static char line[1000];
522         int pktlen, len, i;
523         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
524
525         if (addr)
526                 loginfo("Connection from %s:%s", addr, port);
527
528         alarm(init_timeout ? init_timeout : timeout);
529         pktlen = packet_read_line(0, line, sizeof(line));
530         alarm(0);
531
532         len = strlen(line);
533         if (pktlen != len)
534                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
535                         (int) pktlen - len,
536                         (int) pktlen - len, line + len + 1);
537         if (len && line[len-1] == '\n') {
538                 line[--len] = 0;
539                 pktlen--;
540         }
541
542         free(hostname);
543         free(canon_hostname);
544         free(ip_address);
545         free(tcp_port);
546         hostname = canon_hostname = ip_address = tcp_port = NULL;
547
548         if (len != pktlen)
549                 parse_host_arg(line + len + 1, pktlen - len - 1);
550
551         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
552                 struct daemon_service *s = &(daemon_service[i]);
553                 int namelen = strlen(s->name);
554                 if (!prefixcmp(line, "git-") &&
555                     !strncmp(s->name, line + 4, namelen) &&
556                     line[namelen + 4] == ' ') {
557                         /*
558                          * Note: The directory here is probably context sensitive,
559                          * and might depend on the actual service being performed.
560                          */
561                         return run_service(line + namelen + 5, s);
562                 }
563         }
564
565         logerror("Protocol error: '%s'", line);
566         return -1;
567 }
568
569 static int addrcmp(const struct sockaddr_storage *s1,
570     const struct sockaddr_storage *s2)
571 {
572         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
573         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
574
575         if (sa1->sa_family != sa2->sa_family)
576                 return sa1->sa_family - sa2->sa_family;
577         if (sa1->sa_family == AF_INET)
578                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
579                     &((struct sockaddr_in *)s2)->sin_addr,
580                     sizeof(struct in_addr));
581 #ifndef NO_IPV6
582         if (sa1->sa_family == AF_INET6)
583                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
584                     &((struct sockaddr_in6 *)s2)->sin6_addr,
585                     sizeof(struct in6_addr));
586 #endif
587         return 0;
588 }
589
590 static int max_connections = 32;
591
592 static unsigned int live_children;
593
594 static struct child {
595         struct child *next;
596         struct child_process cld;
597         struct sockaddr_storage address;
598 } *firstborn;
599
600 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
601 {
602         struct child *newborn, **cradle;
603
604         newborn = xcalloc(1, sizeof(*newborn));
605         live_children++;
606         memcpy(&newborn->cld, cld, sizeof(*cld));
607         memcpy(&newborn->address, addr, addrlen);
608         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
609                 if (!addrcmp(&(*cradle)->address, &newborn->address))
610                         break;
611         newborn->next = *cradle;
612         *cradle = newborn;
613 }
614
615 /*
616  * This gets called if the number of connections grows
617  * past "max_connections".
618  *
619  * We kill the newest connection from a duplicate IP.
620  */
621 static void kill_some_child(void)
622 {
623         const struct child *blanket, *next;
624
625         if (!(blanket = firstborn))
626                 return;
627
628         for (; (next = blanket->next); blanket = next)
629                 if (!addrcmp(&blanket->address, &next->address)) {
630                         kill(blanket->cld.pid, SIGTERM);
631                         break;
632                 }
633 }
634
635 static void check_dead_children(void)
636 {
637         int status;
638         pid_t pid;
639
640         struct child **cradle, *blanket;
641         for (cradle = &firstborn; (blanket = *cradle);)
642                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
643                         const char *dead = "";
644                         if (status)
645                                 dead = " (with error)";
646                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
647
648                         /* remove the child */
649                         *cradle = blanket->next;
650                         live_children--;
651                         free(blanket);
652                 } else
653                         cradle = &blanket->next;
654 }
655
656 static char **cld_argv;
657 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
658 {
659         struct child_process cld = { 0 };
660         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
661         char *env[] = { addrbuf, portbuf, NULL };
662
663         if (max_connections && live_children >= max_connections) {
664                 kill_some_child();
665                 sleep(1);  /* give it some time to die */
666                 check_dead_children();
667                 if (live_children >= max_connections) {
668                         close(incoming);
669                         logerror("Too many children, dropping connection");
670                         return;
671                 }
672         }
673
674         if (addr->sa_family == AF_INET) {
675                 struct sockaddr_in *sin_addr = (void *) addr;
676                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
677                     sizeof(addrbuf) - 12);
678                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
679                     ntohs(sin_addr->sin_port));
680 #ifndef NO_IPV6
681         } else if (addr && addr->sa_family == AF_INET6) {
682                 struct sockaddr_in6 *sin6_addr = (void *) addr;
683
684                 char *buf = addrbuf + 12;
685                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
686                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
687                     sizeof(addrbuf) - 13);
688                 strcat(buf, "]");
689
690                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
691                     ntohs(sin6_addr->sin6_port));
692 #endif
693         }
694
695         cld.env = (const char **)env;
696         cld.argv = (const char **)cld_argv;
697         cld.in = incoming;
698         cld.out = dup(incoming);
699
700         if (start_command(&cld))
701                 logerror("unable to fork");
702         else
703                 add_child(&cld, addr, addrlen);
704         close(incoming);
705 }
706
707 static void child_handler(int signo)
708 {
709         /*
710          * Otherwise empty handler because systemcalls will get interrupted
711          * upon signal receipt
712          * SysV needs the handler to be rearmed
713          */
714         signal(SIGCHLD, child_handler);
715 }
716
717 static int set_reuse_addr(int sockfd)
718 {
719         int on = 1;
720
721         if (!reuseaddr)
722                 return 0;
723         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
724                           &on, sizeof(on));
725 }
726
727 struct socketlist {
728         int *list;
729         size_t nr;
730         size_t alloc;
731 };
732
733 #ifndef NO_IPV6
734
735 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
736 {
737         int socknum = 0;
738         int maxfd = -1;
739         char pbuf[NI_MAXSERV];
740         struct addrinfo hints, *ai0, *ai;
741         int gai;
742         long flags;
743
744         sprintf(pbuf, "%d", listen_port);
745         memset(&hints, 0, sizeof(hints));
746         hints.ai_family = AF_UNSPEC;
747         hints.ai_socktype = SOCK_STREAM;
748         hints.ai_protocol = IPPROTO_TCP;
749         hints.ai_flags = AI_PASSIVE;
750
751         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
752         if (gai) {
753                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
754                 return 0;
755         }
756
757         for (ai = ai0; ai; ai = ai->ai_next) {
758                 int sockfd;
759
760                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
761                 if (sockfd < 0)
762                         continue;
763                 if (sockfd >= FD_SETSIZE) {
764                         logerror("Socket descriptor too large");
765                         close(sockfd);
766                         continue;
767                 }
768
769 #ifdef IPV6_V6ONLY
770                 if (ai->ai_family == AF_INET6) {
771                         int on = 1;
772                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
773                                    &on, sizeof(on));
774                         /* Note: error is not fatal */
775                 }
776 #endif
777
778                 if (set_reuse_addr(sockfd)) {
779                         close(sockfd);
780                         continue;
781                 }
782
783                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
784                         close(sockfd);
785                         continue;       /* not fatal */
786                 }
787                 if (listen(sockfd, 5) < 0) {
788                         close(sockfd);
789                         continue;       /* not fatal */
790                 }
791
792                 flags = fcntl(sockfd, F_GETFD, 0);
793                 if (flags >= 0)
794                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
795
796                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
797                 socklist->list[socklist->nr++] = sockfd;
798                 socknum++;
799
800                 if (maxfd < sockfd)
801                         maxfd = sockfd;
802         }
803
804         freeaddrinfo(ai0);
805
806         return socknum;
807 }
808
809 #else /* NO_IPV6 */
810
811 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
812 {
813         struct sockaddr_in sin;
814         int sockfd;
815         long flags;
816
817         memset(&sin, 0, sizeof sin);
818         sin.sin_family = AF_INET;
819         sin.sin_port = htons(listen_port);
820
821         if (listen_addr) {
822                 /* Well, host better be an IP address here. */
823                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
824                         return 0;
825         } else {
826                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
827         }
828
829         sockfd = socket(AF_INET, SOCK_STREAM, 0);
830         if (sockfd < 0)
831                 return 0;
832
833         if (set_reuse_addr(sockfd)) {
834                 close(sockfd);
835                 return 0;
836         }
837
838         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
839                 close(sockfd);
840                 return 0;
841         }
842
843         if (listen(sockfd, 5) < 0) {
844                 close(sockfd);
845                 return 0;
846         }
847
848         flags = fcntl(sockfd, F_GETFD, 0);
849         if (flags >= 0)
850                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
851
852         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
853         socklist->list[socklist->nr++] = sockfd;
854         return 1;
855 }
856
857 #endif
858
859 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
860 {
861         if (!listen_addr->nr)
862                 setup_named_sock(NULL, listen_port, socklist);
863         else {
864                 int i, socknum;
865                 for (i = 0; i < listen_addr->nr; i++) {
866                         socknum = setup_named_sock(listen_addr->items[i].string,
867                                                    listen_port, socklist);
868
869                         if (socknum == 0)
870                                 logerror("unable to allocate any listen sockets for host %s on port %u",
871                                          listen_addr->items[i].string, listen_port);
872                 }
873         }
874 }
875
876 static int service_loop(struct socketlist *socklist)
877 {
878         struct pollfd *pfd;
879         int i;
880
881         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
882
883         for (i = 0; i < socklist->nr; i++) {
884                 pfd[i].fd = socklist->list[i];
885                 pfd[i].events = POLLIN;
886         }
887
888         signal(SIGCHLD, child_handler);
889
890         for (;;) {
891                 int i;
892
893                 check_dead_children();
894
895                 if (poll(pfd, socklist->nr, -1) < 0) {
896                         if (errno != EINTR) {
897                                 logerror("Poll failed, resuming: %s",
898                                       strerror(errno));
899                                 sleep(1);
900                         }
901                         continue;
902                 }
903
904                 for (i = 0; i < socklist->nr; i++) {
905                         if (pfd[i].revents & POLLIN) {
906                                 union {
907                                         struct sockaddr sa;
908                                         struct sockaddr_in sai;
909 #ifndef NO_IPV6
910                                         struct sockaddr_in6 sai6;
911 #endif
912                                 } ss;
913                                 socklen_t sslen = sizeof(ss);
914                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
915                                 if (incoming < 0) {
916                                         switch (errno) {
917                                         case EAGAIN:
918                                         case EINTR:
919                                         case ECONNABORTED:
920                                                 continue;
921                                         default:
922                                                 die_errno("accept returned");
923                                         }
924                                 }
925                                 handle(incoming, &ss.sa, sslen);
926                         }
927                 }
928         }
929 }
930
931 /* if any standard file descriptor is missing open it to /dev/null */
932 static void sanitize_stdfds(void)
933 {
934         int fd = open("/dev/null", O_RDWR, 0);
935         while (fd != -1 && fd < 2)
936                 fd = dup(fd);
937         if (fd == -1)
938                 die_errno("open /dev/null or dup failed");
939         if (fd > 2)
940                 close(fd);
941 }
942
943 #ifdef NO_POSIX_GOODIES
944
945 struct credentials;
946
947 static void drop_privileges(struct credentials *cred)
948 {
949         /* nothing */
950 }
951
952 static void daemonize(void)
953 {
954         die("--detach not supported on this platform");
955 }
956
957 static struct credentials *prepare_credentials(const char *user_name,
958     const char *group_name)
959 {
960         die("--user not supported on this platform");
961 }
962
963 #else
964
965 struct credentials {
966         struct passwd *pass;
967         gid_t gid;
968 };
969
970 static void drop_privileges(struct credentials *cred)
971 {
972         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
973             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
974                 die("cannot drop privileges");
975 }
976
977 static struct credentials *prepare_credentials(const char *user_name,
978     const char *group_name)
979 {
980         static struct credentials c;
981
982         c.pass = getpwnam(user_name);
983         if (!c.pass)
984                 die("user not found - %s", user_name);
985
986         if (!group_name)
987                 c.gid = c.pass->pw_gid;
988         else {
989                 struct group *group = getgrnam(group_name);
990                 if (!group)
991                         die("group not found - %s", group_name);
992
993                 c.gid = group->gr_gid;
994         }
995
996         return &c;
997 }
998
999 static void daemonize(void)
1000 {
1001         switch (fork()) {
1002                 case 0:
1003                         break;
1004                 case -1:
1005                         die_errno("fork failed");
1006                 default:
1007                         exit(0);
1008         }
1009         if (setsid() == -1)
1010                 die_errno("setsid failed");
1011         close(0);
1012         close(1);
1013         close(2);
1014         sanitize_stdfds();
1015 }
1016 #endif
1017
1018 static void store_pid(const char *path)
1019 {
1020         FILE *f = fopen(path, "w");
1021         if (!f)
1022                 die_errno("cannot open pid file '%s'", path);
1023         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1024                 die_errno("failed to write pid file '%s'", path);
1025 }
1026
1027 static int serve(struct string_list *listen_addr, int listen_port,
1028     struct credentials *cred)
1029 {
1030         struct socketlist socklist = { NULL, 0, 0 };
1031
1032         socksetup(listen_addr, listen_port, &socklist);
1033         if (socklist.nr == 0)
1034                 die("unable to allocate any listen sockets on port %u",
1035                     listen_port);
1036
1037         drop_privileges(cred);
1038
1039         return service_loop(&socklist);
1040 }
1041
1042 int main(int argc, char **argv)
1043 {
1044         int listen_port = 0;
1045         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1046         int serve_mode = 0, inetd_mode = 0;
1047         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1048         int detach = 0;
1049         struct credentials *cred = NULL;
1050         int i;
1051
1052         git_extract_argv0_path(argv[0]);
1053
1054         for (i = 1; i < argc; i++) {
1055                 char *arg = argv[i];
1056
1057                 if (!prefixcmp(arg, "--listen=")) {
1058                         string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1059                         continue;
1060                 }
1061                 if (!prefixcmp(arg, "--port=")) {
1062                         char *end;
1063                         unsigned long n;
1064                         n = strtoul(arg+7, &end, 0);
1065                         if (arg[7] && !*end) {
1066                                 listen_port = n;
1067                                 continue;
1068                         }
1069                 }
1070                 if (!strcmp(arg, "--serve")) {
1071                         serve_mode = 1;
1072                         continue;
1073                 }
1074                 if (!strcmp(arg, "--inetd")) {
1075                         inetd_mode = 1;
1076                         log_syslog = 1;
1077                         continue;
1078                 }
1079                 if (!strcmp(arg, "--verbose")) {
1080                         verbose = 1;
1081                         continue;
1082                 }
1083                 if (!strcmp(arg, "--syslog")) {
1084                         log_syslog = 1;
1085                         continue;
1086                 }
1087                 if (!strcmp(arg, "--export-all")) {
1088                         export_all_trees = 1;
1089                         continue;
1090                 }
1091                 if (!prefixcmp(arg, "--timeout=")) {
1092                         timeout = atoi(arg+10);
1093                         continue;
1094                 }
1095                 if (!prefixcmp(arg, "--init-timeout=")) {
1096                         init_timeout = atoi(arg+15);
1097                         continue;
1098                 }
1099                 if (!prefixcmp(arg, "--max-connections=")) {
1100                         max_connections = atoi(arg+18);
1101                         if (max_connections < 0)
1102                                 max_connections = 0;            /* unlimited */
1103                         continue;
1104                 }
1105                 if (!strcmp(arg, "--strict-paths")) {
1106                         strict_paths = 1;
1107                         continue;
1108                 }
1109                 if (!prefixcmp(arg, "--base-path=")) {
1110                         base_path = arg+12;
1111                         continue;
1112                 }
1113                 if (!strcmp(arg, "--base-path-relaxed")) {
1114                         base_path_relaxed = 1;
1115                         continue;
1116                 }
1117                 if (!prefixcmp(arg, "--interpolated-path=")) {
1118                         interpolated_path = arg+20;
1119                         continue;
1120                 }
1121                 if (!strcmp(arg, "--reuseaddr")) {
1122                         reuseaddr = 1;
1123                         continue;
1124                 }
1125                 if (!strcmp(arg, "--user-path")) {
1126                         user_path = "";
1127                         continue;
1128                 }
1129                 if (!prefixcmp(arg, "--user-path=")) {
1130                         user_path = arg + 12;
1131                         continue;
1132                 }
1133                 if (!prefixcmp(arg, "--pid-file=")) {
1134                         pid_file = arg + 11;
1135                         continue;
1136                 }
1137                 if (!strcmp(arg, "--detach")) {
1138                         detach = 1;
1139                         log_syslog = 1;
1140                         continue;
1141                 }
1142                 if (!prefixcmp(arg, "--user=")) {
1143                         user_name = arg + 7;
1144                         continue;
1145                 }
1146                 if (!prefixcmp(arg, "--group=")) {
1147                         group_name = arg + 8;
1148                         continue;
1149                 }
1150                 if (!prefixcmp(arg, "--enable=")) {
1151                         enable_service(arg + 9, 1);
1152                         continue;
1153                 }
1154                 if (!prefixcmp(arg, "--disable=")) {
1155                         enable_service(arg + 10, 0);
1156                         continue;
1157                 }
1158                 if (!prefixcmp(arg, "--allow-override=")) {
1159                         make_service_overridable(arg + 17, 1);
1160                         continue;
1161                 }
1162                 if (!prefixcmp(arg, "--forbid-override=")) {
1163                         make_service_overridable(arg + 18, 0);
1164                         continue;
1165                 }
1166                 if (!strcmp(arg, "--")) {
1167                         ok_paths = &argv[i+1];
1168                         break;
1169                 } else if (arg[0] != '-') {
1170                         ok_paths = &argv[i];
1171                         break;
1172                 }
1173
1174                 usage(daemon_usage);
1175         }
1176
1177         if (log_syslog) {
1178                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1179                 set_die_routine(daemon_die);
1180         } else
1181                 /* avoid splitting a message in the middle */
1182                 setvbuf(stderr, NULL, _IOFBF, 4096);
1183
1184         if (inetd_mode && (detach || group_name || user_name))
1185                 die("--detach, --user and --group are incompatible with --inetd");
1186
1187         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1188                 die("--listen= and --port= are incompatible with --inetd");
1189         else if (listen_port == 0)
1190                 listen_port = DEFAULT_GIT_PORT;
1191
1192         if (group_name && !user_name)
1193                 die("--group supplied without --user");
1194
1195         if (user_name)
1196                 cred = prepare_credentials(user_name, group_name);
1197
1198         if (strict_paths && (!ok_paths || !*ok_paths))
1199                 die("option --strict-paths requires a whitelist");
1200
1201         if (base_path && !is_directory(base_path))
1202                 die("base-path '%s' does not exist or is not a directory",
1203                     base_path);
1204
1205         if (inetd_mode) {
1206                 if (!freopen("/dev/null", "w", stderr))
1207                         die_errno("failed to redirect stderr to /dev/null");
1208         }
1209
1210         if (inetd_mode || serve_mode)
1211                 return execute();
1212
1213         if (detach) {
1214                 daemonize();
1215                 loginfo("Ready to rumble");
1216         }
1217         else
1218                 sanitize_stdfds();
1219
1220         if (pid_file)
1221                 store_pid(pid_file);
1222
1223         /* prepare argv for serving-processes */
1224         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1225         for (i = 0; i < argc; ++i)
1226                 cld_argv[i] = argv[i];
1227         cld_argv[argc] = "--serve";
1228         cld_argv[argc+1] = NULL;
1229
1230         return serve(&listen_addr, listen_port, cred);
1231 }