Merge branch 'cb/leading-path-removal'
[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 #ifdef NO_INITGROUPS
17 #define initgroups(x, y) (0) /* nothing */
18 #endif
19
20 static int log_syslog;
21 static int verbose;
22 static int reuseaddr;
23
24 static const char daemon_usage[] =
25 "git daemon [--verbose] [--syslog] [--export-all]\n"
26 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
27 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
28 "           [--user-path | --user-path=<path>]\n"
29 "           [--interpolated-path=<path>]\n"
30 "           [--reuseaddr] [--pid-file=<file>]\n"
31 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
32 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
33 "                      [--detach] [--user=<user> [--group=<group>]]\n"
34 "           [<directory>...]";
35
36 /* List of acceptable pathname prefixes */
37 static char **ok_paths;
38 static int strict_paths;
39
40 /* If this is set, git-daemon-export-ok is not required */
41 static int export_all_trees;
42
43 /* Take all paths relative to this one if non-NULL */
44 static char *base_path;
45 static char *interpolated_path;
46 static int base_path_relaxed;
47
48 /* Flag indicating client sent extra args. */
49 static int saw_extended_args;
50
51 /* If defined, ~user notation is allowed and the string is inserted
52  * after ~user/.  E.g. a request to git://host/~alice/frotz would
53  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
54  */
55 static const char *user_path;
56
57 /* Timeout, and initial timeout */
58 static unsigned int timeout;
59 static unsigned int init_timeout;
60
61 static char *hostname;
62 static char *canon_hostname;
63 static char *ip_address;
64 static char *tcp_port;
65
66 static void logreport(int priority, const char *err, va_list params)
67 {
68         if (log_syslog) {
69                 char buf[1024];
70                 vsnprintf(buf, sizeof(buf), err, params);
71                 syslog(priority, "%s", buf);
72         } else {
73                 /*
74                  * Since stderr is set to buffered mode, the
75                  * logging of different processes will not overlap
76                  * unless they overflow the (rather big) buffers.
77                  */
78                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
79                 vfprintf(stderr, err, params);
80                 fputc('\n', stderr);
81                 fflush(stderr);
82         }
83 }
84
85 __attribute__((format (printf, 1, 2)))
86 static void logerror(const char *err, ...)
87 {
88         va_list params;
89         va_start(params, err);
90         logreport(LOG_ERR, err, params);
91         va_end(params);
92 }
93
94 __attribute__((format (printf, 1, 2)))
95 static void loginfo(const char *err, ...)
96 {
97         va_list params;
98         if (!verbose)
99                 return;
100         va_start(params, err);
101         logreport(LOG_INFO, err, params);
102         va_end(params);
103 }
104
105 static void NORETURN daemon_die(const char *err, va_list params)
106 {
107         logreport(LOG_ERR, err, params);
108         exit(1);
109 }
110
111 static char *path_ok(char *directory)
112 {
113         static char rpath[PATH_MAX];
114         static char interp_path[PATH_MAX];
115         char *path;
116         char *dir;
117
118         dir = directory;
119
120         if (daemon_avoid_alias(dir)) {
121                 logerror("'%s': aliased", dir);
122                 return NULL;
123         }
124
125         if (*dir == '~') {
126                 if (!user_path) {
127                         logerror("'%s': User-path not allowed", dir);
128                         return NULL;
129                 }
130                 if (*user_path) {
131                         /* Got either "~alice" or "~alice/foo";
132                          * rewrite them to "~alice/%s" or
133                          * "~alice/%s/foo".
134                          */
135                         int namlen, restlen = strlen(dir);
136                         char *slash = strchr(dir, '/');
137                         if (!slash)
138                                 slash = dir + restlen;
139                         namlen = slash - dir;
140                         restlen -= namlen;
141                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
142                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
143                                  namlen, dir, user_path, restlen, slash);
144                         dir = rpath;
145                 }
146         }
147         else if (interpolated_path && saw_extended_args) {
148                 struct strbuf expanded_path = STRBUF_INIT;
149                 struct strbuf_expand_dict_entry dict[6];
150
151                 dict[0].placeholder = "H"; dict[0].value = hostname;
152                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
153                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
154                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
155                 dict[4].placeholder = "D"; dict[4].value = directory;
156                 dict[5].placeholder = NULL; dict[5].value = NULL;
157                 if (*dir != '/') {
158                         /* Allow only absolute */
159                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
160                         return NULL;
161                 }
162
163                 strbuf_expand(&expanded_path, interpolated_path,
164                                 strbuf_expand_dict_cb, &dict);
165                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
166                 strbuf_release(&expanded_path);
167                 loginfo("Interpolated dir '%s'", interp_path);
168
169                 dir = interp_path;
170         }
171         else if (base_path) {
172                 if (*dir != '/') {
173                         /* Allow only absolute */
174                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
175                         return NULL;
176                 }
177                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
178                 dir = rpath;
179         }
180
181         path = enter_repo(dir, strict_paths);
182         if (!path && base_path && base_path_relaxed) {
183                 /*
184                  * if we fail and base_path_relaxed is enabled, try without
185                  * prefixing the base path
186                  */
187                 dir = directory;
188                 path = enter_repo(dir, strict_paths);
189         }
190
191         if (!path) {
192                 logerror("'%s' does not appear to be a git repository", dir);
193                 return NULL;
194         }
195
196         if ( ok_paths && *ok_paths ) {
197                 char **pp;
198                 int pathlen = strlen(path);
199
200                 /* The validation is done on the paths after enter_repo
201                  * appends optional {.git,.git/.git} and friends, but
202                  * it does not use getcwd().  So if your /pub is
203                  * a symlink to /mnt/pub, you can whitelist /pub and
204                  * do not have to say /mnt/pub.
205                  * Do not say /pub/.
206                  */
207                 for ( pp = ok_paths ; *pp ; pp++ ) {
208                         int len = strlen(*pp);
209                         if (len <= pathlen &&
210                             !memcmp(*pp, path, len) &&
211                             (path[len] == '\0' ||
212                              (!strict_paths && path[len] == '/')))
213                                 return path;
214                 }
215         }
216         else {
217                 /* be backwards compatible */
218                 if (!strict_paths)
219                         return path;
220         }
221
222         logerror("'%s': not in whitelist", path);
223         return NULL;            /* Fallthrough. Deny by default */
224 }
225
226 typedef int (*daemon_service_fn)(void);
227 struct daemon_service {
228         const char *name;
229         const char *config_name;
230         daemon_service_fn fn;
231         int enabled;
232         int overridable;
233 };
234
235 static struct daemon_service *service_looking_at;
236 static int service_enabled;
237
238 static int git_daemon_config(const char *var, const char *value, void *cb)
239 {
240         if (!prefixcmp(var, "daemon.") &&
241             !strcmp(var + 7, service_looking_at->config_name)) {
242                 service_enabled = git_config_bool(var, value);
243                 return 0;
244         }
245
246         /* we are not interested in parsing any other configuration here */
247         return 0;
248 }
249
250 static int run_service(char *dir, struct daemon_service *service)
251 {
252         const char *path;
253         int enabled = service->enabled;
254
255         loginfo("Request %s for '%s'", service->name, dir);
256
257         if (!enabled && !service->overridable) {
258                 logerror("'%s': service not enabled.", service->name);
259                 errno = EACCES;
260                 return -1;
261         }
262
263         if (!(path = path_ok(dir)))
264                 return -1;
265
266         /*
267          * Security on the cheap.
268          *
269          * We want a readable HEAD, usable "objects" directory, and
270          * a "git-daemon-export-ok" flag that says that the other side
271          * is ok with us doing this.
272          *
273          * path_ok() uses enter_repo() and does whitelist checking.
274          * We only need to make sure the repository is exported.
275          */
276
277         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
278                 logerror("'%s': repository not exported.", path);
279                 errno = EACCES;
280                 return -1;
281         }
282
283         if (service->overridable) {
284                 service_looking_at = service;
285                 service_enabled = -1;
286                 git_config(git_daemon_config, NULL);
287                 if (0 <= service_enabled)
288                         enabled = service_enabled;
289         }
290         if (!enabled) {
291                 logerror("'%s': service not enabled for '%s'",
292                          service->name, path);
293                 errno = EACCES;
294                 return -1;
295         }
296
297         /*
298          * We'll ignore SIGTERM from now on, we have a
299          * good client.
300          */
301         signal(SIGTERM, SIG_IGN);
302
303         return service->fn();
304 }
305
306 static void copy_to_log(int fd)
307 {
308         struct strbuf line = STRBUF_INIT;
309         FILE *fp;
310
311         fp = fdopen(fd, "r");
312         if (fp == NULL) {
313                 logerror("fdopen of error channel failed");
314                 close(fd);
315                 return;
316         }
317
318         while (strbuf_getline(&line, fp, '\n') != EOF) {
319                 logerror("%s", line.buf);
320                 strbuf_setlen(&line, 0);
321         }
322
323         strbuf_release(&line);
324         fclose(fp);
325 }
326
327 static int run_service_command(const char **argv)
328 {
329         struct child_process cld;
330
331         memset(&cld, 0, sizeof(cld));
332         cld.argv = argv;
333         cld.git_cmd = 1;
334         cld.err = -1;
335         if (start_command(&cld))
336                 return -1;
337
338         close(0);
339         close(1);
340
341         copy_to_log(cld.err);
342
343         return finish_command(&cld);
344 }
345
346 static int upload_pack(void)
347 {
348         /* Timeout as string */
349         char timeout_buf[64];
350         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
351
352         argv[2] = timeout_buf;
353
354         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
355         return run_service_command(argv);
356 }
357
358 static int upload_archive(void)
359 {
360         static const char *argv[] = { "upload-archive", ".", NULL };
361         return run_service_command(argv);
362 }
363
364 static int receive_pack(void)
365 {
366         static const char *argv[] = { "receive-pack", ".", NULL };
367         return run_service_command(argv);
368 }
369
370 static struct daemon_service daemon_service[] = {
371         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
372         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
373         { "receive-pack", "receivepack", receive_pack, 0, 1 },
374 };
375
376 static void enable_service(const char *name, int ena)
377 {
378         int i;
379         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
380                 if (!strcmp(daemon_service[i].name, name)) {
381                         daemon_service[i].enabled = ena;
382                         return;
383                 }
384         }
385         die("No such service %s", name);
386 }
387
388 static void make_service_overridable(const char *name, int ena)
389 {
390         int i;
391         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
392                 if (!strcmp(daemon_service[i].name, name)) {
393                         daemon_service[i].overridable = ena;
394                         return;
395                 }
396         }
397         die("No such service %s", name);
398 }
399
400 static char *xstrdup_tolower(const char *str)
401 {
402         char *p, *dup = xstrdup(str);
403         for (p = dup; *p; p++)
404                 *p = tolower(*p);
405         return dup;
406 }
407
408 static void parse_host_and_port(char *hostport, char **host,
409         char **port)
410 {
411         if (*hostport == '[') {
412                 char *end;
413
414                 end = strchr(hostport, ']');
415                 if (!end)
416                         die("Invalid request ('[' without ']')");
417                 *end = '\0';
418                 *host = hostport + 1;
419                 if (!end[1])
420                         *port = NULL;
421                 else if (end[1] == ':')
422                         *port = end + 2;
423                 else
424                         die("Garbage after end of host part");
425         } else {
426                 *host = hostport;
427                 *port = strrchr(hostport, ':');
428                 if (*port) {
429                         **port = '\0';
430                         ++*port;
431                 }
432         }
433 }
434
435 /*
436  * Read the host as supplied by the client connection.
437  */
438 static void parse_host_arg(char *extra_args, int buflen)
439 {
440         char *val;
441         int vallen;
442         char *end = extra_args + buflen;
443
444         if (extra_args < end && *extra_args) {
445                 saw_extended_args = 1;
446                 if (strncasecmp("host=", extra_args, 5) == 0) {
447                         val = extra_args + 5;
448                         vallen = strlen(val) + 1;
449                         if (*val) {
450                                 /* Split <host>:<port> at colon. */
451                                 char *host;
452                                 char *port;
453                                 parse_host_and_port(val, &host, &port);
454                                 if (port) {
455                                         free(tcp_port);
456                                         tcp_port = xstrdup(port);
457                                 }
458                                 free(hostname);
459                                 hostname = xstrdup_tolower(host);
460                         }
461
462                         /* On to the next one */
463                         extra_args = val + vallen;
464                 }
465                 if (extra_args < end && *extra_args)
466                         die("Invalid request");
467         }
468
469         /*
470          * Locate canonical hostname and its IP address.
471          */
472         if (hostname) {
473 #ifndef NO_IPV6
474                 struct addrinfo hints;
475                 struct addrinfo *ai;
476                 int gai;
477                 static char addrbuf[HOST_NAME_MAX + 1];
478
479                 memset(&hints, 0, sizeof(hints));
480                 hints.ai_flags = AI_CANONNAME;
481
482                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
483                 if (!gai) {
484                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
485
486                         inet_ntop(AF_INET, &sin_addr->sin_addr,
487                                   addrbuf, sizeof(addrbuf));
488                         free(ip_address);
489                         ip_address = xstrdup(addrbuf);
490
491                         free(canon_hostname);
492                         canon_hostname = xstrdup(ai->ai_canonname ?
493                                                  ai->ai_canonname : ip_address);
494
495                         freeaddrinfo(ai);
496                 }
497 #else
498                 struct hostent *hent;
499                 struct sockaddr_in sa;
500                 char **ap;
501                 static char addrbuf[HOST_NAME_MAX + 1];
502
503                 hent = gethostbyname(hostname);
504
505                 ap = hent->h_addr_list;
506                 memset(&sa, 0, sizeof sa);
507                 sa.sin_family = hent->h_addrtype;
508                 sa.sin_port = htons(0);
509                 memcpy(&sa.sin_addr, *ap, hent->h_length);
510
511                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
512                           addrbuf, sizeof(addrbuf));
513
514                 free(canon_hostname);
515                 canon_hostname = xstrdup(hent->h_name);
516                 free(ip_address);
517                 ip_address = xstrdup(addrbuf);
518 #endif
519         }
520 }
521
522
523 static int execute(void)
524 {
525         static char line[1000];
526         int pktlen, len, i;
527         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
528
529         if (addr)
530                 loginfo("Connection from %s:%s", addr, port);
531
532         alarm(init_timeout ? init_timeout : timeout);
533         pktlen = packet_read_line(0, line, sizeof(line));
534         alarm(0);
535
536         len = strlen(line);
537         if (pktlen != len)
538                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
539                         (int) pktlen - len,
540                         (int) pktlen - len, line + len + 1);
541         if (len && line[len-1] == '\n') {
542                 line[--len] = 0;
543                 pktlen--;
544         }
545
546         free(hostname);
547         free(canon_hostname);
548         free(ip_address);
549         free(tcp_port);
550         hostname = canon_hostname = ip_address = tcp_port = NULL;
551
552         if (len != pktlen)
553                 parse_host_arg(line + len + 1, pktlen - len - 1);
554
555         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
556                 struct daemon_service *s = &(daemon_service[i]);
557                 int namelen = strlen(s->name);
558                 if (!prefixcmp(line, "git-") &&
559                     !strncmp(s->name, line + 4, namelen) &&
560                     line[namelen + 4] == ' ') {
561                         /*
562                          * Note: The directory here is probably context sensitive,
563                          * and might depend on the actual service being performed.
564                          */
565                         return run_service(line + namelen + 5, s);
566                 }
567         }
568
569         logerror("Protocol error: '%s'", line);
570         return -1;
571 }
572
573 static int addrcmp(const struct sockaddr_storage *s1,
574     const struct sockaddr_storage *s2)
575 {
576         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
577         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
578
579         if (sa1->sa_family != sa2->sa_family)
580                 return sa1->sa_family - sa2->sa_family;
581         if (sa1->sa_family == AF_INET)
582                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
583                     &((struct sockaddr_in *)s2)->sin_addr,
584                     sizeof(struct in_addr));
585 #ifndef NO_IPV6
586         if (sa1->sa_family == AF_INET6)
587                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
588                     &((struct sockaddr_in6 *)s2)->sin6_addr,
589                     sizeof(struct in6_addr));
590 #endif
591         return 0;
592 }
593
594 static int max_connections = 32;
595
596 static unsigned int live_children;
597
598 static struct child {
599         struct child *next;
600         struct child_process cld;
601         struct sockaddr_storage address;
602 } *firstborn;
603
604 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
605 {
606         struct child *newborn, **cradle;
607
608         newborn = xcalloc(1, sizeof(*newborn));
609         live_children++;
610         memcpy(&newborn->cld, cld, sizeof(*cld));
611         memcpy(&newborn->address, addr, addrlen);
612         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
613                 if (!addrcmp(&(*cradle)->address, &newborn->address))
614                         break;
615         newborn->next = *cradle;
616         *cradle = newborn;
617 }
618
619 /*
620  * This gets called if the number of connections grows
621  * past "max_connections".
622  *
623  * We kill the newest connection from a duplicate IP.
624  */
625 static void kill_some_child(void)
626 {
627         const struct child *blanket, *next;
628
629         if (!(blanket = firstborn))
630                 return;
631
632         for (; (next = blanket->next); blanket = next)
633                 if (!addrcmp(&blanket->address, &next->address)) {
634                         kill(blanket->cld.pid, SIGTERM);
635                         break;
636                 }
637 }
638
639 static void check_dead_children(void)
640 {
641         int status;
642         pid_t pid;
643
644         struct child **cradle, *blanket;
645         for (cradle = &firstborn; (blanket = *cradle);)
646                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
647                         const char *dead = "";
648                         if (status)
649                                 dead = " (with error)";
650                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
651
652                         /* remove the child */
653                         *cradle = blanket->next;
654                         live_children--;
655                         free(blanket);
656                 } else
657                         cradle = &blanket->next;
658 }
659
660 static char **cld_argv;
661 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
662 {
663         struct child_process cld = { 0 };
664         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
665         char *env[] = { addrbuf, portbuf, NULL };
666
667         if (max_connections && live_children >= max_connections) {
668                 kill_some_child();
669                 sleep(1);  /* give it some time to die */
670                 check_dead_children();
671                 if (live_children >= max_connections) {
672                         close(incoming);
673                         logerror("Too many children, dropping connection");
674                         return;
675                 }
676         }
677
678         if (addr->sa_family == AF_INET) {
679                 struct sockaddr_in *sin_addr = (void *) addr;
680                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
681                     sizeof(addrbuf) - 12);
682                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
683                     ntohs(sin_addr->sin_port));
684 #ifndef NO_IPV6
685         } else if (addr && addr->sa_family == AF_INET6) {
686                 struct sockaddr_in6 *sin6_addr = (void *) addr;
687
688                 char *buf = addrbuf + 12;
689                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
690                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
691                     sizeof(addrbuf) - 13);
692                 strcat(buf, "]");
693
694                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
695                     ntohs(sin6_addr->sin6_port));
696 #endif
697         }
698
699         cld.env = (const char **)env;
700         cld.argv = (const char **)cld_argv;
701         cld.in = incoming;
702         cld.out = dup(incoming);
703
704         if (start_command(&cld))
705                 logerror("unable to fork");
706         else
707                 add_child(&cld, addr, addrlen);
708         close(incoming);
709 }
710
711 static void child_handler(int signo)
712 {
713         /*
714          * Otherwise empty handler because systemcalls will get interrupted
715          * upon signal receipt
716          * SysV needs the handler to be rearmed
717          */
718         signal(SIGCHLD, child_handler);
719 }
720
721 static int set_reuse_addr(int sockfd)
722 {
723         int on = 1;
724
725         if (!reuseaddr)
726                 return 0;
727         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
728                           &on, sizeof(on));
729 }
730
731 struct socketlist {
732         int *list;
733         size_t nr;
734         size_t alloc;
735 };
736
737 #ifndef NO_IPV6
738
739 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
740 {
741         int socknum = 0;
742         int maxfd = -1;
743         char pbuf[NI_MAXSERV];
744         struct addrinfo hints, *ai0, *ai;
745         int gai;
746         long flags;
747
748         sprintf(pbuf, "%d", listen_port);
749         memset(&hints, 0, sizeof(hints));
750         hints.ai_family = AF_UNSPEC;
751         hints.ai_socktype = SOCK_STREAM;
752         hints.ai_protocol = IPPROTO_TCP;
753         hints.ai_flags = AI_PASSIVE;
754
755         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
756         if (gai) {
757                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
758                 return 0;
759         }
760
761         for (ai = ai0; ai; ai = ai->ai_next) {
762                 int sockfd;
763
764                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
765                 if (sockfd < 0)
766                         continue;
767                 if (sockfd >= FD_SETSIZE) {
768                         logerror("Socket descriptor too large");
769                         close(sockfd);
770                         continue;
771                 }
772
773 #ifdef IPV6_V6ONLY
774                 if (ai->ai_family == AF_INET6) {
775                         int on = 1;
776                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
777                                    &on, sizeof(on));
778                         /* Note: error is not fatal */
779                 }
780 #endif
781
782                 if (set_reuse_addr(sockfd)) {
783                         close(sockfd);
784                         continue;
785                 }
786
787                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
788                         close(sockfd);
789                         continue;       /* not fatal */
790                 }
791                 if (listen(sockfd, 5) < 0) {
792                         close(sockfd);
793                         continue;       /* not fatal */
794                 }
795
796                 flags = fcntl(sockfd, F_GETFD, 0);
797                 if (flags >= 0)
798                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
799
800                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
801                 socklist->list[socklist->nr++] = sockfd;
802                 socknum++;
803
804                 if (maxfd < sockfd)
805                         maxfd = sockfd;
806         }
807
808         freeaddrinfo(ai0);
809
810         return socknum;
811 }
812
813 #else /* NO_IPV6 */
814
815 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
816 {
817         struct sockaddr_in sin;
818         int sockfd;
819         long flags;
820
821         memset(&sin, 0, sizeof sin);
822         sin.sin_family = AF_INET;
823         sin.sin_port = htons(listen_port);
824
825         if (listen_addr) {
826                 /* Well, host better be an IP address here. */
827                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
828                         return 0;
829         } else {
830                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
831         }
832
833         sockfd = socket(AF_INET, SOCK_STREAM, 0);
834         if (sockfd < 0)
835                 return 0;
836
837         if (set_reuse_addr(sockfd)) {
838                 close(sockfd);
839                 return 0;
840         }
841
842         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
843                 close(sockfd);
844                 return 0;
845         }
846
847         if (listen(sockfd, 5) < 0) {
848                 close(sockfd);
849                 return 0;
850         }
851
852         flags = fcntl(sockfd, F_GETFD, 0);
853         if (flags >= 0)
854                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
855
856         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
857         socklist->list[socklist->nr++] = sockfd;
858         return 1;
859 }
860
861 #endif
862
863 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
864 {
865         if (!listen_addr->nr)
866                 setup_named_sock(NULL, listen_port, socklist);
867         else {
868                 int i, socknum;
869                 for (i = 0; i < listen_addr->nr; i++) {
870                         socknum = setup_named_sock(listen_addr->items[i].string,
871                                                    listen_port, socklist);
872
873                         if (socknum == 0)
874                                 logerror("unable to allocate any listen sockets for host %s on port %u",
875                                          listen_addr->items[i].string, listen_port);
876                 }
877         }
878 }
879
880 static int service_loop(struct socketlist *socklist)
881 {
882         struct pollfd *pfd;
883         int i;
884
885         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
886
887         for (i = 0; i < socklist->nr; i++) {
888                 pfd[i].fd = socklist->list[i];
889                 pfd[i].events = POLLIN;
890         }
891
892         signal(SIGCHLD, child_handler);
893
894         for (;;) {
895                 int i;
896
897                 check_dead_children();
898
899                 if (poll(pfd, socklist->nr, -1) < 0) {
900                         if (errno != EINTR) {
901                                 logerror("Poll failed, resuming: %s",
902                                       strerror(errno));
903                                 sleep(1);
904                         }
905                         continue;
906                 }
907
908                 for (i = 0; i < socklist->nr; i++) {
909                         if (pfd[i].revents & POLLIN) {
910                                 union {
911                                         struct sockaddr sa;
912                                         struct sockaddr_in sai;
913 #ifndef NO_IPV6
914                                         struct sockaddr_in6 sai6;
915 #endif
916                                 } ss;
917                                 socklen_t sslen = sizeof(ss);
918                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
919                                 if (incoming < 0) {
920                                         switch (errno) {
921                                         case EAGAIN:
922                                         case EINTR:
923                                         case ECONNABORTED:
924                                                 continue;
925                                         default:
926                                                 die_errno("accept returned");
927                                         }
928                                 }
929                                 handle(incoming, &ss.sa, sslen);
930                         }
931                 }
932         }
933 }
934
935 /* if any standard file descriptor is missing open it to /dev/null */
936 static void sanitize_stdfds(void)
937 {
938         int fd = open("/dev/null", O_RDWR, 0);
939         while (fd != -1 && fd < 2)
940                 fd = dup(fd);
941         if (fd == -1)
942                 die_errno("open /dev/null or dup failed");
943         if (fd > 2)
944                 close(fd);
945 }
946
947 #ifdef NO_POSIX_GOODIES
948
949 struct credentials;
950
951 static void drop_privileges(struct credentials *cred)
952 {
953         /* nothing */
954 }
955
956 static void daemonize(void)
957 {
958         die("--detach not supported on this platform");
959 }
960
961 static struct credentials *prepare_credentials(const char *user_name,
962     const char *group_name)
963 {
964         die("--user not supported on this platform");
965 }
966
967 #else
968
969 struct credentials {
970         struct passwd *pass;
971         gid_t gid;
972 };
973
974 static void drop_privileges(struct credentials *cred)
975 {
976         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
977             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
978                 die("cannot drop privileges");
979 }
980
981 static struct credentials *prepare_credentials(const char *user_name,
982     const char *group_name)
983 {
984         static struct credentials c;
985
986         c.pass = getpwnam(user_name);
987         if (!c.pass)
988                 die("user not found - %s", user_name);
989
990         if (!group_name)
991                 c.gid = c.pass->pw_gid;
992         else {
993                 struct group *group = getgrnam(group_name);
994                 if (!group)
995                         die("group not found - %s", group_name);
996
997                 c.gid = group->gr_gid;
998         }
999
1000         return &c;
1001 }
1002
1003 static void daemonize(void)
1004 {
1005         switch (fork()) {
1006                 case 0:
1007                         break;
1008                 case -1:
1009                         die_errno("fork failed");
1010                 default:
1011                         exit(0);
1012         }
1013         if (setsid() == -1)
1014                 die_errno("setsid failed");
1015         close(0);
1016         close(1);
1017         close(2);
1018         sanitize_stdfds();
1019 }
1020 #endif
1021
1022 static void store_pid(const char *path)
1023 {
1024         FILE *f = fopen(path, "w");
1025         if (!f)
1026                 die_errno("cannot open pid file '%s'", path);
1027         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1028                 die_errno("failed to write pid file '%s'", path);
1029 }
1030
1031 static int serve(struct string_list *listen_addr, int listen_port,
1032     struct credentials *cred)
1033 {
1034         struct socketlist socklist = { NULL, 0, 0 };
1035
1036         socksetup(listen_addr, listen_port, &socklist);
1037         if (socklist.nr == 0)
1038                 die("unable to allocate any listen sockets on port %u",
1039                     listen_port);
1040
1041         drop_privileges(cred);
1042
1043         return service_loop(&socklist);
1044 }
1045
1046 int main(int argc, char **argv)
1047 {
1048         int listen_port = 0;
1049         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1050         int serve_mode = 0, inetd_mode = 0;
1051         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1052         int detach = 0;
1053         struct credentials *cred = NULL;
1054         int i;
1055
1056         git_extract_argv0_path(argv[0]);
1057
1058         for (i = 1; i < argc; i++) {
1059                 char *arg = argv[i];
1060
1061                 if (!prefixcmp(arg, "--listen=")) {
1062                         string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1063                         continue;
1064                 }
1065                 if (!prefixcmp(arg, "--port=")) {
1066                         char *end;
1067                         unsigned long n;
1068                         n = strtoul(arg+7, &end, 0);
1069                         if (arg[7] && !*end) {
1070                                 listen_port = n;
1071                                 continue;
1072                         }
1073                 }
1074                 if (!strcmp(arg, "--serve")) {
1075                         serve_mode = 1;
1076                         continue;
1077                 }
1078                 if (!strcmp(arg, "--inetd")) {
1079                         inetd_mode = 1;
1080                         log_syslog = 1;
1081                         continue;
1082                 }
1083                 if (!strcmp(arg, "--verbose")) {
1084                         verbose = 1;
1085                         continue;
1086                 }
1087                 if (!strcmp(arg, "--syslog")) {
1088                         log_syslog = 1;
1089                         continue;
1090                 }
1091                 if (!strcmp(arg, "--export-all")) {
1092                         export_all_trees = 1;
1093                         continue;
1094                 }
1095                 if (!prefixcmp(arg, "--timeout=")) {
1096                         timeout = atoi(arg+10);
1097                         continue;
1098                 }
1099                 if (!prefixcmp(arg, "--init-timeout=")) {
1100                         init_timeout = atoi(arg+15);
1101                         continue;
1102                 }
1103                 if (!prefixcmp(arg, "--max-connections=")) {
1104                         max_connections = atoi(arg+18);
1105                         if (max_connections < 0)
1106                                 max_connections = 0;            /* unlimited */
1107                         continue;
1108                 }
1109                 if (!strcmp(arg, "--strict-paths")) {
1110                         strict_paths = 1;
1111                         continue;
1112                 }
1113                 if (!prefixcmp(arg, "--base-path=")) {
1114                         base_path = arg+12;
1115                         continue;
1116                 }
1117                 if (!strcmp(arg, "--base-path-relaxed")) {
1118                         base_path_relaxed = 1;
1119                         continue;
1120                 }
1121                 if (!prefixcmp(arg, "--interpolated-path=")) {
1122                         interpolated_path = arg+20;
1123                         continue;
1124                 }
1125                 if (!strcmp(arg, "--reuseaddr")) {
1126                         reuseaddr = 1;
1127                         continue;
1128                 }
1129                 if (!strcmp(arg, "--user-path")) {
1130                         user_path = "";
1131                         continue;
1132                 }
1133                 if (!prefixcmp(arg, "--user-path=")) {
1134                         user_path = arg + 12;
1135                         continue;
1136                 }
1137                 if (!prefixcmp(arg, "--pid-file=")) {
1138                         pid_file = arg + 11;
1139                         continue;
1140                 }
1141                 if (!strcmp(arg, "--detach")) {
1142                         detach = 1;
1143                         log_syslog = 1;
1144                         continue;
1145                 }
1146                 if (!prefixcmp(arg, "--user=")) {
1147                         user_name = arg + 7;
1148                         continue;
1149                 }
1150                 if (!prefixcmp(arg, "--group=")) {
1151                         group_name = arg + 8;
1152                         continue;
1153                 }
1154                 if (!prefixcmp(arg, "--enable=")) {
1155                         enable_service(arg + 9, 1);
1156                         continue;
1157                 }
1158                 if (!prefixcmp(arg, "--disable=")) {
1159                         enable_service(arg + 10, 0);
1160                         continue;
1161                 }
1162                 if (!prefixcmp(arg, "--allow-override=")) {
1163                         make_service_overridable(arg + 17, 1);
1164                         continue;
1165                 }
1166                 if (!prefixcmp(arg, "--forbid-override=")) {
1167                         make_service_overridable(arg + 18, 0);
1168                         continue;
1169                 }
1170                 if (!strcmp(arg, "--")) {
1171                         ok_paths = &argv[i+1];
1172                         break;
1173                 } else if (arg[0] != '-') {
1174                         ok_paths = &argv[i];
1175                         break;
1176                 }
1177
1178                 usage(daemon_usage);
1179         }
1180
1181         if (log_syslog) {
1182                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1183                 set_die_routine(daemon_die);
1184         } else
1185                 /* avoid splitting a message in the middle */
1186                 setvbuf(stderr, NULL, _IOFBF, 4096);
1187
1188         if (inetd_mode && (detach || group_name || user_name))
1189                 die("--detach, --user and --group are incompatible with --inetd");
1190
1191         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1192                 die("--listen= and --port= are incompatible with --inetd");
1193         else if (listen_port == 0)
1194                 listen_port = DEFAULT_GIT_PORT;
1195
1196         if (group_name && !user_name)
1197                 die("--group supplied without --user");
1198
1199         if (user_name)
1200                 cred = prepare_credentials(user_name, group_name);
1201
1202         if (strict_paths && (!ok_paths || !*ok_paths))
1203                 die("option --strict-paths requires a whitelist");
1204
1205         if (base_path && !is_directory(base_path))
1206                 die("base-path '%s' does not exist or is not a directory",
1207                     base_path);
1208
1209         if (inetd_mode) {
1210                 if (!freopen("/dev/null", "w", stderr))
1211                         die_errno("failed to redirect stderr to /dev/null");
1212         }
1213
1214         if (inetd_mode || serve_mode)
1215                 return execute();
1216
1217         if (detach) {
1218                 daemonize();
1219                 loginfo("Ready to rumble");
1220         }
1221         else
1222                 sanitize_stdfds();
1223
1224         if (pid_file)
1225                 store_pid(pid_file);
1226
1227         /* prepare argv for serving-processes */
1228         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1229         for (i = 0; i < argc; ++i)
1230                 cld_argv[i] = argv[i];
1231         cld_argv[argc] = "--serve";
1232         cld_argv[argc+1] = NULL;
1233
1234         return serve(&listen_addr, listen_port, cred);
1235 }