Merge branch 'jk/checkout-from-tree' into maint
[git] / daemon.c
1 #include "cache.h"
2 #include "pkt-line.h"
3 #include "exec_cmd.h"
4 #include "run-command.h"
5 #include "strbuf.h"
6 #include "string-list.h"
7
8 #ifndef HOST_NAME_MAX
9 #define HOST_NAME_MAX 256
10 #endif
11
12 #ifdef NO_INITGROUPS
13 #define initgroups(x, y) (0) /* nothing */
14 #endif
15
16 static int log_syslog;
17 static int verbose;
18 static int reuseaddr;
19 static int informative_errors;
20
21 static const char daemon_usage[] =
22 "git daemon [--verbose] [--syslog] [--export-all]\n"
23 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
24 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
25 "           [--user-path | --user-path=<path>]\n"
26 "           [--interpolated-path=<path>]\n"
27 "           [--reuseaddr] [--pid-file=<file>]\n"
28 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
29 "           [--access-hook=<path>]\n"
30 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
31 "                      [--detach] [--user=<user> [--group=<group>]]\n"
32 "           [<directory>...]";
33
34 /* List of acceptable pathname prefixes */
35 static char **ok_paths;
36 static int strict_paths;
37
38 /* If this is set, git-daemon-export-ok is not required */
39 static int export_all_trees;
40
41 /* Take all paths relative to this one if non-NULL */
42 static const char *base_path;
43 static const char *interpolated_path;
44 static int base_path_relaxed;
45
46 /* Flag indicating client sent extra args. */
47 static int saw_extended_args;
48
49 /* If defined, ~user notation is allowed and the string is inserted
50  * after ~user/.  E.g. a request to git://host/~alice/frotz would
51  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
52  */
53 static const char *user_path;
54
55 /* Timeout, and initial timeout */
56 static unsigned int timeout;
57 static unsigned int init_timeout;
58
59 static char *hostname;
60 static char *canon_hostname;
61 static char *ip_address;
62 static char *tcp_port;
63
64 static void logreport(int priority, const char *err, va_list params)
65 {
66         if (log_syslog) {
67                 char buf[1024];
68                 vsnprintf(buf, sizeof(buf), err, params);
69                 syslog(priority, "%s", buf);
70         } else {
71                 /*
72                  * Since stderr is set to buffered mode, the
73                  * logging of different processes will not overlap
74                  * unless they overflow the (rather big) buffers.
75                  */
76                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
77                 vfprintf(stderr, err, params);
78                 fputc('\n', stderr);
79                 fflush(stderr);
80         }
81 }
82
83 __attribute__((format (printf, 1, 2)))
84 static void logerror(const char *err, ...)
85 {
86         va_list params;
87         va_start(params, err);
88         logreport(LOG_ERR, err, params);
89         va_end(params);
90 }
91
92 __attribute__((format (printf, 1, 2)))
93 static void loginfo(const char *err, ...)
94 {
95         va_list params;
96         if (!verbose)
97                 return;
98         va_start(params, err);
99         logreport(LOG_INFO, err, params);
100         va_end(params);
101 }
102
103 static void NORETURN daemon_die(const char *err, va_list params)
104 {
105         logreport(LOG_ERR, err, params);
106         exit(1);
107 }
108
109 static const char *path_ok(const char *directory)
110 {
111         static char rpath[PATH_MAX];
112         static char interp_path[PATH_MAX];
113         const char *path;
114         const char *dir;
115
116         dir = directory;
117
118         if (daemon_avoid_alias(dir)) {
119                 logerror("'%s': aliased", dir);
120                 return NULL;
121         }
122
123         if (*dir == '~') {
124                 if (!user_path) {
125                         logerror("'%s': User-path not allowed", dir);
126                         return NULL;
127                 }
128                 if (*user_path) {
129                         /* Got either "~alice" or "~alice/foo";
130                          * rewrite them to "~alice/%s" or
131                          * "~alice/%s/foo".
132                          */
133                         int namlen, restlen = strlen(dir);
134                         const char *slash = strchr(dir, '/');
135                         if (!slash)
136                                 slash = dir + restlen;
137                         namlen = slash - dir;
138                         restlen -= namlen;
139                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
140                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
141                                  namlen, dir, user_path, restlen, slash);
142                         dir = rpath;
143                 }
144         }
145         else if (interpolated_path && saw_extended_args) {
146                 struct strbuf expanded_path = STRBUF_INIT;
147                 struct strbuf_expand_dict_entry dict[6];
148
149                 dict[0].placeholder = "H"; dict[0].value = hostname;
150                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
151                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
152                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
153                 dict[4].placeholder = "D"; dict[4].value = directory;
154                 dict[5].placeholder = NULL; dict[5].value = NULL;
155                 if (*dir != '/') {
156                         /* Allow only absolute */
157                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
158                         return NULL;
159                 }
160
161                 strbuf_expand(&expanded_path, interpolated_path,
162                                 strbuf_expand_dict_cb, &dict);
163                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
164                 strbuf_release(&expanded_path);
165                 loginfo("Interpolated dir '%s'", interp_path);
166
167                 dir = interp_path;
168         }
169         else if (base_path) {
170                 if (*dir != '/') {
171                         /* Allow only absolute */
172                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
173                         return NULL;
174                 }
175                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
176                 dir = rpath;
177         }
178
179         path = enter_repo(dir, strict_paths);
180         if (!path && base_path && base_path_relaxed) {
181                 /*
182                  * if we fail and base_path_relaxed is enabled, try without
183                  * prefixing the base path
184                  */
185                 dir = directory;
186                 path = enter_repo(dir, strict_paths);
187         }
188
189         if (!path) {
190                 logerror("'%s' does not appear to be a git repository", dir);
191                 return NULL;
192         }
193
194         if ( ok_paths && *ok_paths ) {
195                 char **pp;
196                 int pathlen = strlen(path);
197
198                 /* The validation is done on the paths after enter_repo
199                  * appends optional {.git,.git/.git} and friends, but
200                  * it does not use getcwd().  So if your /pub is
201                  * a symlink to /mnt/pub, you can whitelist /pub and
202                  * do not have to say /mnt/pub.
203                  * Do not say /pub/.
204                  */
205                 for ( pp = ok_paths ; *pp ; pp++ ) {
206                         int len = strlen(*pp);
207                         if (len <= pathlen &&
208                             !memcmp(*pp, path, len) &&
209                             (path[len] == '\0' ||
210                              (!strict_paths && path[len] == '/')))
211                                 return path;
212                 }
213         }
214         else {
215                 /* be backwards compatible */
216                 if (!strict_paths)
217                         return path;
218         }
219
220         logerror("'%s': not in whitelist", path);
221         return NULL;            /* Fallthrough. Deny by default */
222 }
223
224 typedef int (*daemon_service_fn)(void);
225 struct daemon_service {
226         const char *name;
227         const char *config_name;
228         daemon_service_fn fn;
229         int enabled;
230         int overridable;
231 };
232
233 static int daemon_error(const char *dir, const char *msg)
234 {
235         if (!informative_errors)
236                 msg = "access denied or repository not exported";
237         packet_write(1, "ERR %s: %s", msg, dir);
238         return -1;
239 }
240
241 static const char *access_hook;
242
243 static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
244 {
245         struct child_process child = CHILD_PROCESS_INIT;
246         struct strbuf buf = STRBUF_INIT;
247         const char *argv[8];
248         const char **arg = argv;
249         char *eol;
250         int seen_errors = 0;
251
252 #define STRARG(x) ((x) ? (x) : "")
253         *arg++ = access_hook;
254         *arg++ = service->name;
255         *arg++ = path;
256         *arg++ = STRARG(hostname);
257         *arg++ = STRARG(canon_hostname);
258         *arg++ = STRARG(ip_address);
259         *arg++ = STRARG(tcp_port);
260         *arg = NULL;
261 #undef STRARG
262
263         child.use_shell = 1;
264         child.argv = argv;
265         child.no_stdin = 1;
266         child.no_stderr = 1;
267         child.out = -1;
268         if (start_command(&child)) {
269                 logerror("daemon access hook '%s' failed to start",
270                          access_hook);
271                 goto error_return;
272         }
273         if (strbuf_read(&buf, child.out, 0) < 0) {
274                 logerror("failed to read from pipe to daemon access hook '%s'",
275                          access_hook);
276                 strbuf_reset(&buf);
277                 seen_errors = 1;
278         }
279         if (close(child.out) < 0) {
280                 logerror("failed to close pipe to daemon access hook '%s'",
281                          access_hook);
282                 seen_errors = 1;
283         }
284         if (finish_command(&child))
285                 seen_errors = 1;
286
287         if (!seen_errors) {
288                 strbuf_release(&buf);
289                 return 0;
290         }
291
292 error_return:
293         strbuf_ltrim(&buf);
294         if (!buf.len)
295                 strbuf_addstr(&buf, "service rejected");
296         eol = strchr(buf.buf, '\n');
297         if (eol)
298                 *eol = '\0';
299         errno = EACCES;
300         daemon_error(dir, buf.buf);
301         strbuf_release(&buf);
302         return -1;
303 }
304
305 static int run_service(const char *dir, struct daemon_service *service)
306 {
307         const char *path;
308         int enabled = service->enabled;
309         struct strbuf var = STRBUF_INIT;
310
311         loginfo("Request %s for '%s'", service->name, dir);
312
313         if (!enabled && !service->overridable) {
314                 logerror("'%s': service not enabled.", service->name);
315                 errno = EACCES;
316                 return daemon_error(dir, "service not enabled");
317         }
318
319         if (!(path = path_ok(dir)))
320                 return daemon_error(dir, "no such repository");
321
322         /*
323          * Security on the cheap.
324          *
325          * We want a readable HEAD, usable "objects" directory, and
326          * a "git-daemon-export-ok" flag that says that the other side
327          * is ok with us doing this.
328          *
329          * path_ok() uses enter_repo() and does whitelist checking.
330          * We only need to make sure the repository is exported.
331          */
332
333         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
334                 logerror("'%s': repository not exported.", path);
335                 errno = EACCES;
336                 return daemon_error(dir, "repository not exported");
337         }
338
339         if (service->overridable) {
340                 strbuf_addf(&var, "daemon.%s", service->config_name);
341                 git_config_get_bool(var.buf, &enabled);
342                 strbuf_release(&var);
343         }
344         if (!enabled) {
345                 logerror("'%s': service not enabled for '%s'",
346                          service->name, path);
347                 errno = EACCES;
348                 return daemon_error(dir, "service not enabled");
349         }
350
351         /*
352          * Optionally, a hook can choose to deny access to the
353          * repository depending on the phase of the moon.
354          */
355         if (access_hook && run_access_hook(service, dir, path))
356                 return -1;
357
358         /*
359          * We'll ignore SIGTERM from now on, we have a
360          * good client.
361          */
362         signal(SIGTERM, SIG_IGN);
363
364         return service->fn();
365 }
366
367 static void copy_to_log(int fd)
368 {
369         struct strbuf line = STRBUF_INIT;
370         FILE *fp;
371
372         fp = fdopen(fd, "r");
373         if (fp == NULL) {
374                 logerror("fdopen of error channel failed");
375                 close(fd);
376                 return;
377         }
378
379         while (strbuf_getline(&line, fp, '\n') != EOF) {
380                 logerror("%s", line.buf);
381                 strbuf_setlen(&line, 0);
382         }
383
384         strbuf_release(&line);
385         fclose(fp);
386 }
387
388 static int run_service_command(const char **argv)
389 {
390         struct child_process cld = CHILD_PROCESS_INIT;
391
392         cld.argv = argv;
393         cld.git_cmd = 1;
394         cld.err = -1;
395         if (start_command(&cld))
396                 return -1;
397
398         close(0);
399         close(1);
400
401         copy_to_log(cld.err);
402
403         return finish_command(&cld);
404 }
405
406 static int upload_pack(void)
407 {
408         /* Timeout as string */
409         char timeout_buf[64];
410         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
411
412         argv[2] = timeout_buf;
413
414         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
415         return run_service_command(argv);
416 }
417
418 static int upload_archive(void)
419 {
420         static const char *argv[] = { "upload-archive", ".", NULL };
421         return run_service_command(argv);
422 }
423
424 static int receive_pack(void)
425 {
426         static const char *argv[] = { "receive-pack", ".", NULL };
427         return run_service_command(argv);
428 }
429
430 static struct daemon_service daemon_service[] = {
431         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
432         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
433         { "receive-pack", "receivepack", receive_pack, 0, 1 },
434 };
435
436 static void enable_service(const char *name, int ena)
437 {
438         int i;
439         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
440                 if (!strcmp(daemon_service[i].name, name)) {
441                         daemon_service[i].enabled = ena;
442                         return;
443                 }
444         }
445         die("No such service %s", name);
446 }
447
448 static void make_service_overridable(const char *name, int ena)
449 {
450         int i;
451         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
452                 if (!strcmp(daemon_service[i].name, name)) {
453                         daemon_service[i].overridable = ena;
454                         return;
455                 }
456         }
457         die("No such service %s", name);
458 }
459
460 static void parse_host_and_port(char *hostport, char **host,
461         char **port)
462 {
463         if (*hostport == '[') {
464                 char *end;
465
466                 end = strchr(hostport, ']');
467                 if (!end)
468                         die("Invalid request ('[' without ']')");
469                 *end = '\0';
470                 *host = hostport + 1;
471                 if (!end[1])
472                         *port = NULL;
473                 else if (end[1] == ':')
474                         *port = end + 2;
475                 else
476                         die("Garbage after end of host part");
477         } else {
478                 *host = hostport;
479                 *port = strrchr(hostport, ':');
480                 if (*port) {
481                         **port = '\0';
482                         ++*port;
483                 }
484         }
485 }
486
487 /*
488  * Read the host as supplied by the client connection.
489  */
490 static void parse_host_arg(char *extra_args, int buflen)
491 {
492         char *val;
493         int vallen;
494         char *end = extra_args + buflen;
495
496         if (extra_args < end && *extra_args) {
497                 saw_extended_args = 1;
498                 if (strncasecmp("host=", extra_args, 5) == 0) {
499                         val = extra_args + 5;
500                         vallen = strlen(val) + 1;
501                         if (*val) {
502                                 /* Split <host>:<port> at colon. */
503                                 char *host;
504                                 char *port;
505                                 parse_host_and_port(val, &host, &port);
506                                 if (port) {
507                                         free(tcp_port);
508                                         tcp_port = xstrdup(port);
509                                 }
510                                 free(hostname);
511                                 hostname = xstrdup_tolower(host);
512                         }
513
514                         /* On to the next one */
515                         extra_args = val + vallen;
516                 }
517                 if (extra_args < end && *extra_args)
518                         die("Invalid request");
519         }
520
521         /*
522          * Locate canonical hostname and its IP address.
523          */
524         if (hostname) {
525 #ifndef NO_IPV6
526                 struct addrinfo hints;
527                 struct addrinfo *ai;
528                 int gai;
529                 static char addrbuf[HOST_NAME_MAX + 1];
530
531                 memset(&hints, 0, sizeof(hints));
532                 hints.ai_flags = AI_CANONNAME;
533
534                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
535                 if (!gai) {
536                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
537
538                         inet_ntop(AF_INET, &sin_addr->sin_addr,
539                                   addrbuf, sizeof(addrbuf));
540                         free(ip_address);
541                         ip_address = xstrdup(addrbuf);
542
543                         free(canon_hostname);
544                         canon_hostname = xstrdup(ai->ai_canonname ?
545                                                  ai->ai_canonname : ip_address);
546
547                         freeaddrinfo(ai);
548                 }
549 #else
550                 struct hostent *hent;
551                 struct sockaddr_in sa;
552                 char **ap;
553                 static char addrbuf[HOST_NAME_MAX + 1];
554
555                 hent = gethostbyname(hostname);
556                 if (hent) {
557                         ap = hent->h_addr_list;
558                         memset(&sa, 0, sizeof sa);
559                         sa.sin_family = hent->h_addrtype;
560                         sa.sin_port = htons(0);
561                         memcpy(&sa.sin_addr, *ap, hent->h_length);
562
563                         inet_ntop(hent->h_addrtype, &sa.sin_addr,
564                                   addrbuf, sizeof(addrbuf));
565
566                         free(canon_hostname);
567                         canon_hostname = xstrdup(hent->h_name);
568                         free(ip_address);
569                         ip_address = xstrdup(addrbuf);
570                 }
571 #endif
572         }
573 }
574
575
576 static int execute(void)
577 {
578         char *line = packet_buffer;
579         int pktlen, len, i;
580         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
581
582         if (addr)
583                 loginfo("Connection from %s:%s", addr, port);
584
585         alarm(init_timeout ? init_timeout : timeout);
586         pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
587         alarm(0);
588
589         len = strlen(line);
590         if (pktlen != len)
591                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
592                         (int) pktlen - len,
593                         (int) pktlen - len, line + len + 1);
594         if (len && line[len-1] == '\n') {
595                 line[--len] = 0;
596                 pktlen--;
597         }
598
599         free(hostname);
600         free(canon_hostname);
601         free(ip_address);
602         free(tcp_port);
603         hostname = canon_hostname = ip_address = tcp_port = NULL;
604
605         if (len != pktlen)
606                 parse_host_arg(line + len + 1, pktlen - len - 1);
607
608         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
609                 struct daemon_service *s = &(daemon_service[i]);
610                 const char *arg;
611
612                 if (skip_prefix(line, "git-", &arg) &&
613                     skip_prefix(arg, s->name, &arg) &&
614                     *arg++ == ' ') {
615                         /*
616                          * Note: The directory here is probably context sensitive,
617                          * and might depend on the actual service being performed.
618                          */
619                         return run_service(arg, s);
620                 }
621         }
622
623         logerror("Protocol error: '%s'", line);
624         return -1;
625 }
626
627 static int addrcmp(const struct sockaddr_storage *s1,
628     const struct sockaddr_storage *s2)
629 {
630         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
631         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
632
633         if (sa1->sa_family != sa2->sa_family)
634                 return sa1->sa_family - sa2->sa_family;
635         if (sa1->sa_family == AF_INET)
636                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
637                     &((struct sockaddr_in *)s2)->sin_addr,
638                     sizeof(struct in_addr));
639 #ifndef NO_IPV6
640         if (sa1->sa_family == AF_INET6)
641                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
642                     &((struct sockaddr_in6 *)s2)->sin6_addr,
643                     sizeof(struct in6_addr));
644 #endif
645         return 0;
646 }
647
648 static int max_connections = 32;
649
650 static unsigned int live_children;
651
652 static struct child {
653         struct child *next;
654         struct child_process cld;
655         struct sockaddr_storage address;
656 } *firstborn;
657
658 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
659 {
660         struct child *newborn, **cradle;
661
662         newborn = xcalloc(1, sizeof(*newborn));
663         live_children++;
664         memcpy(&newborn->cld, cld, sizeof(*cld));
665         memcpy(&newborn->address, addr, addrlen);
666         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
667                 if (!addrcmp(&(*cradle)->address, &newborn->address))
668                         break;
669         newborn->next = *cradle;
670         *cradle = newborn;
671 }
672
673 /*
674  * This gets called if the number of connections grows
675  * past "max_connections".
676  *
677  * We kill the newest connection from a duplicate IP.
678  */
679 static void kill_some_child(void)
680 {
681         const struct child *blanket, *next;
682
683         if (!(blanket = firstborn))
684                 return;
685
686         for (; (next = blanket->next); blanket = next)
687                 if (!addrcmp(&blanket->address, &next->address)) {
688                         kill(blanket->cld.pid, SIGTERM);
689                         break;
690                 }
691 }
692
693 static void check_dead_children(void)
694 {
695         int status;
696         pid_t pid;
697
698         struct child **cradle, *blanket;
699         for (cradle = &firstborn; (blanket = *cradle);)
700                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
701                         const char *dead = "";
702                         if (status)
703                                 dead = " (with error)";
704                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
705
706                         /* remove the child */
707                         *cradle = blanket->next;
708                         live_children--;
709                         free(blanket);
710                 } else
711                         cradle = &blanket->next;
712 }
713
714 static char **cld_argv;
715 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
716 {
717         struct child_process cld = CHILD_PROCESS_INIT;
718         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
719         char *env[] = { addrbuf, portbuf, NULL };
720
721         if (max_connections && live_children >= max_connections) {
722                 kill_some_child();
723                 sleep(1);  /* give it some time to die */
724                 check_dead_children();
725                 if (live_children >= max_connections) {
726                         close(incoming);
727                         logerror("Too many children, dropping connection");
728                         return;
729                 }
730         }
731
732         if (addr->sa_family == AF_INET) {
733                 struct sockaddr_in *sin_addr = (void *) addr;
734                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
735                     sizeof(addrbuf) - 12);
736                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
737                     ntohs(sin_addr->sin_port));
738 #ifndef NO_IPV6
739         } else if (addr->sa_family == AF_INET6) {
740                 struct sockaddr_in6 *sin6_addr = (void *) addr;
741
742                 char *buf = addrbuf + 12;
743                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
744                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
745                     sizeof(addrbuf) - 13);
746                 strcat(buf, "]");
747
748                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
749                     ntohs(sin6_addr->sin6_port));
750 #endif
751         }
752
753         cld.env = (const char **)env;
754         cld.argv = (const char **)cld_argv;
755         cld.in = incoming;
756         cld.out = dup(incoming);
757
758         if (start_command(&cld))
759                 logerror("unable to fork");
760         else
761                 add_child(&cld, addr, addrlen);
762 }
763
764 static void child_handler(int signo)
765 {
766         /*
767          * Otherwise empty handler because systemcalls will get interrupted
768          * upon signal receipt
769          * SysV needs the handler to be rearmed
770          */
771         signal(SIGCHLD, child_handler);
772 }
773
774 static int set_reuse_addr(int sockfd)
775 {
776         int on = 1;
777
778         if (!reuseaddr)
779                 return 0;
780         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
781                           &on, sizeof(on));
782 }
783
784 struct socketlist {
785         int *list;
786         size_t nr;
787         size_t alloc;
788 };
789
790 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
791 {
792 #ifdef NO_IPV6
793         static char ip[INET_ADDRSTRLEN];
794 #else
795         static char ip[INET6_ADDRSTRLEN];
796 #endif
797
798         switch (family) {
799 #ifndef NO_IPV6
800         case AF_INET6:
801                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
802                 break;
803 #endif
804         case AF_INET:
805                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
806                 break;
807         default:
808                 strcpy(ip, "<unknown>");
809         }
810         return ip;
811 }
812
813 #ifndef NO_IPV6
814
815 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
816 {
817         int socknum = 0;
818         char pbuf[NI_MAXSERV];
819         struct addrinfo hints, *ai0, *ai;
820         int gai;
821         long flags;
822
823         sprintf(pbuf, "%d", listen_port);
824         memset(&hints, 0, sizeof(hints));
825         hints.ai_family = AF_UNSPEC;
826         hints.ai_socktype = SOCK_STREAM;
827         hints.ai_protocol = IPPROTO_TCP;
828         hints.ai_flags = AI_PASSIVE;
829
830         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
831         if (gai) {
832                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
833                 return 0;
834         }
835
836         for (ai = ai0; ai; ai = ai->ai_next) {
837                 int sockfd;
838
839                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
840                 if (sockfd < 0)
841                         continue;
842                 if (sockfd >= FD_SETSIZE) {
843                         logerror("Socket descriptor too large");
844                         close(sockfd);
845                         continue;
846                 }
847
848 #ifdef IPV6_V6ONLY
849                 if (ai->ai_family == AF_INET6) {
850                         int on = 1;
851                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
852                                    &on, sizeof(on));
853                         /* Note: error is not fatal */
854                 }
855 #endif
856
857                 if (set_reuse_addr(sockfd)) {
858                         logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
859                         close(sockfd);
860                         continue;
861                 }
862
863                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
864                         logerror("Could not bind to %s: %s",
865                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
866                                  strerror(errno));
867                         close(sockfd);
868                         continue;       /* not fatal */
869                 }
870                 if (listen(sockfd, 5) < 0) {
871                         logerror("Could not listen to %s: %s",
872                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
873                                  strerror(errno));
874                         close(sockfd);
875                         continue;       /* not fatal */
876                 }
877
878                 flags = fcntl(sockfd, F_GETFD, 0);
879                 if (flags >= 0)
880                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
881
882                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
883                 socklist->list[socklist->nr++] = sockfd;
884                 socknum++;
885         }
886
887         freeaddrinfo(ai0);
888
889         return socknum;
890 }
891
892 #else /* NO_IPV6 */
893
894 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
895 {
896         struct sockaddr_in sin;
897         int sockfd;
898         long flags;
899
900         memset(&sin, 0, sizeof sin);
901         sin.sin_family = AF_INET;
902         sin.sin_port = htons(listen_port);
903
904         if (listen_addr) {
905                 /* Well, host better be an IP address here. */
906                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
907                         return 0;
908         } else {
909                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
910         }
911
912         sockfd = socket(AF_INET, SOCK_STREAM, 0);
913         if (sockfd < 0)
914                 return 0;
915
916         if (set_reuse_addr(sockfd)) {
917                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
918                 close(sockfd);
919                 return 0;
920         }
921
922         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
923                 logerror("Could not bind to %s: %s",
924                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
925                          strerror(errno));
926                 close(sockfd);
927                 return 0;
928         }
929
930         if (listen(sockfd, 5) < 0) {
931                 logerror("Could not listen to %s: %s",
932                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
933                          strerror(errno));
934                 close(sockfd);
935                 return 0;
936         }
937
938         flags = fcntl(sockfd, F_GETFD, 0);
939         if (flags >= 0)
940                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
941
942         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
943         socklist->list[socklist->nr++] = sockfd;
944         return 1;
945 }
946
947 #endif
948
949 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
950 {
951         if (!listen_addr->nr)
952                 setup_named_sock(NULL, listen_port, socklist);
953         else {
954                 int i, socknum;
955                 for (i = 0; i < listen_addr->nr; i++) {
956                         socknum = setup_named_sock(listen_addr->items[i].string,
957                                                    listen_port, socklist);
958
959                         if (socknum == 0)
960                                 logerror("unable to allocate any listen sockets for host %s on port %u",
961                                          listen_addr->items[i].string, listen_port);
962                 }
963         }
964 }
965
966 static int service_loop(struct socketlist *socklist)
967 {
968         struct pollfd *pfd;
969         int i;
970
971         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
972
973         for (i = 0; i < socklist->nr; i++) {
974                 pfd[i].fd = socklist->list[i];
975                 pfd[i].events = POLLIN;
976         }
977
978         signal(SIGCHLD, child_handler);
979
980         for (;;) {
981                 int i;
982
983                 check_dead_children();
984
985                 if (poll(pfd, socklist->nr, -1) < 0) {
986                         if (errno != EINTR) {
987                                 logerror("Poll failed, resuming: %s",
988                                       strerror(errno));
989                                 sleep(1);
990                         }
991                         continue;
992                 }
993
994                 for (i = 0; i < socklist->nr; i++) {
995                         if (pfd[i].revents & POLLIN) {
996                                 union {
997                                         struct sockaddr sa;
998                                         struct sockaddr_in sai;
999 #ifndef NO_IPV6
1000                                         struct sockaddr_in6 sai6;
1001 #endif
1002                                 } ss;
1003                                 socklen_t sslen = sizeof(ss);
1004                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1005                                 if (incoming < 0) {
1006                                         switch (errno) {
1007                                         case EAGAIN:
1008                                         case EINTR:
1009                                         case ECONNABORTED:
1010                                                 continue;
1011                                         default:
1012                                                 die_errno("accept returned");
1013                                         }
1014                                 }
1015                                 handle(incoming, &ss.sa, sslen);
1016                         }
1017                 }
1018         }
1019 }
1020
1021 #ifdef NO_POSIX_GOODIES
1022
1023 struct credentials;
1024
1025 static void drop_privileges(struct credentials *cred)
1026 {
1027         /* nothing */
1028 }
1029
1030 static struct credentials *prepare_credentials(const char *user_name,
1031     const char *group_name)
1032 {
1033         die("--user not supported on this platform");
1034 }
1035
1036 #else
1037
1038 struct credentials {
1039         struct passwd *pass;
1040         gid_t gid;
1041 };
1042
1043 static void drop_privileges(struct credentials *cred)
1044 {
1045         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1046             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1047                 die("cannot drop privileges");
1048 }
1049
1050 static struct credentials *prepare_credentials(const char *user_name,
1051     const char *group_name)
1052 {
1053         static struct credentials c;
1054
1055         c.pass = getpwnam(user_name);
1056         if (!c.pass)
1057                 die("user not found - %s", user_name);
1058
1059         if (!group_name)
1060                 c.gid = c.pass->pw_gid;
1061         else {
1062                 struct group *group = getgrnam(group_name);
1063                 if (!group)
1064                         die("group not found - %s", group_name);
1065
1066                 c.gid = group->gr_gid;
1067         }
1068
1069         return &c;
1070 }
1071 #endif
1072
1073 static void store_pid(const char *path)
1074 {
1075         FILE *f = fopen(path, "w");
1076         if (!f)
1077                 die_errno("cannot open pid file '%s'", path);
1078         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1079                 die_errno("failed to write pid file '%s'", path);
1080 }
1081
1082 static int serve(struct string_list *listen_addr, int listen_port,
1083     struct credentials *cred)
1084 {
1085         struct socketlist socklist = { NULL, 0, 0 };
1086
1087         socksetup(listen_addr, listen_port, &socklist);
1088         if (socklist.nr == 0)
1089                 die("unable to allocate any listen sockets on port %u",
1090                     listen_port);
1091
1092         drop_privileges(cred);
1093
1094         loginfo("Ready to rumble");
1095
1096         return service_loop(&socklist);
1097 }
1098
1099 int main(int argc, char **argv)
1100 {
1101         int listen_port = 0;
1102         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1103         int serve_mode = 0, inetd_mode = 0;
1104         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1105         int detach = 0;
1106         struct credentials *cred = NULL;
1107         int i;
1108
1109         git_setup_gettext();
1110
1111         git_extract_argv0_path(argv[0]);
1112
1113         for (i = 1; i < argc; i++) {
1114                 char *arg = argv[i];
1115                 const char *v;
1116
1117                 if (skip_prefix(arg, "--listen=", &v)) {
1118                         string_list_append(&listen_addr, xstrdup_tolower(v));
1119                         continue;
1120                 }
1121                 if (skip_prefix(arg, "--port=", &v)) {
1122                         char *end;
1123                         unsigned long n;
1124                         n = strtoul(v, &end, 0);
1125                         if (*v && !*end) {
1126                                 listen_port = n;
1127                                 continue;
1128                         }
1129                 }
1130                 if (!strcmp(arg, "--serve")) {
1131                         serve_mode = 1;
1132                         continue;
1133                 }
1134                 if (!strcmp(arg, "--inetd")) {
1135                         inetd_mode = 1;
1136                         log_syslog = 1;
1137                         continue;
1138                 }
1139                 if (!strcmp(arg, "--verbose")) {
1140                         verbose = 1;
1141                         continue;
1142                 }
1143                 if (!strcmp(arg, "--syslog")) {
1144                         log_syslog = 1;
1145                         continue;
1146                 }
1147                 if (!strcmp(arg, "--export-all")) {
1148                         export_all_trees = 1;
1149                         continue;
1150                 }
1151                 if (skip_prefix(arg, "--access-hook=", &v)) {
1152                         access_hook = v;
1153                         continue;
1154                 }
1155                 if (skip_prefix(arg, "--timeout=", &v)) {
1156                         timeout = atoi(v);
1157                         continue;
1158                 }
1159                 if (skip_prefix(arg, "--init-timeout=", &v)) {
1160                         init_timeout = atoi(v);
1161                         continue;
1162                 }
1163                 if (skip_prefix(arg, "--max-connections=", &v)) {
1164                         max_connections = atoi(v);
1165                         if (max_connections < 0)
1166                                 max_connections = 0;            /* unlimited */
1167                         continue;
1168                 }
1169                 if (!strcmp(arg, "--strict-paths")) {
1170                         strict_paths = 1;
1171                         continue;
1172                 }
1173                 if (skip_prefix(arg, "--base-path=", &v)) {
1174                         base_path = v;
1175                         continue;
1176                 }
1177                 if (!strcmp(arg, "--base-path-relaxed")) {
1178                         base_path_relaxed = 1;
1179                         continue;
1180                 }
1181                 if (skip_prefix(arg, "--interpolated-path=", &v)) {
1182                         interpolated_path = v;
1183                         continue;
1184                 }
1185                 if (!strcmp(arg, "--reuseaddr")) {
1186                         reuseaddr = 1;
1187                         continue;
1188                 }
1189                 if (!strcmp(arg, "--user-path")) {
1190                         user_path = "";
1191                         continue;
1192                 }
1193                 if (skip_prefix(arg, "--user-path=", &v)) {
1194                         user_path = v;
1195                         continue;
1196                 }
1197                 if (skip_prefix(arg, "--pid-file=", &v)) {
1198                         pid_file = v;
1199                         continue;
1200                 }
1201                 if (!strcmp(arg, "--detach")) {
1202                         detach = 1;
1203                         log_syslog = 1;
1204                         continue;
1205                 }
1206                 if (skip_prefix(arg, "--user=", &v)) {
1207                         user_name = v;
1208                         continue;
1209                 }
1210                 if (skip_prefix(arg, "--group=", &v)) {
1211                         group_name = v;
1212                         continue;
1213                 }
1214                 if (skip_prefix(arg, "--enable=", &v)) {
1215                         enable_service(v, 1);
1216                         continue;
1217                 }
1218                 if (skip_prefix(arg, "--disable=", &v)) {
1219                         enable_service(v, 0);
1220                         continue;
1221                 }
1222                 if (skip_prefix(arg, "--allow-override=", &v)) {
1223                         make_service_overridable(v, 1);
1224                         continue;
1225                 }
1226                 if (skip_prefix(arg, "--forbid-override=", &v)) {
1227                         make_service_overridable(v, 0);
1228                         continue;
1229                 }
1230                 if (!strcmp(arg, "--informative-errors")) {
1231                         informative_errors = 1;
1232                         continue;
1233                 }
1234                 if (!strcmp(arg, "--no-informative-errors")) {
1235                         informative_errors = 0;
1236                         continue;
1237                 }
1238                 if (!strcmp(arg, "--")) {
1239                         ok_paths = &argv[i+1];
1240                         break;
1241                 } else if (arg[0] != '-') {
1242                         ok_paths = &argv[i];
1243                         break;
1244                 }
1245
1246                 usage(daemon_usage);
1247         }
1248
1249         if (log_syslog) {
1250                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1251                 set_die_routine(daemon_die);
1252         } else
1253                 /* avoid splitting a message in the middle */
1254                 setvbuf(stderr, NULL, _IOFBF, 4096);
1255
1256         if (inetd_mode && (detach || group_name || user_name))
1257                 die("--detach, --user and --group are incompatible with --inetd");
1258
1259         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1260                 die("--listen= and --port= are incompatible with --inetd");
1261         else if (listen_port == 0)
1262                 listen_port = DEFAULT_GIT_PORT;
1263
1264         if (group_name && !user_name)
1265                 die("--group supplied without --user");
1266
1267         if (user_name)
1268                 cred = prepare_credentials(user_name, group_name);
1269
1270         if (strict_paths && (!ok_paths || !*ok_paths))
1271                 die("option --strict-paths requires a whitelist");
1272
1273         if (base_path && !is_directory(base_path))
1274                 die("base-path '%s' does not exist or is not a directory",
1275                     base_path);
1276
1277         if (inetd_mode) {
1278                 if (!freopen("/dev/null", "w", stderr))
1279                         die_errno("failed to redirect stderr to /dev/null");
1280         }
1281
1282         if (inetd_mode || serve_mode)
1283                 return execute();
1284
1285         if (detach) {
1286                 if (daemonize())
1287                         die("--detach not supported on this platform");
1288         } else
1289                 sanitize_stdfds();
1290
1291         if (pid_file)
1292                 store_pid(pid_file);
1293
1294         /* prepare argv for serving-processes */
1295         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1296         cld_argv[0] = argv[0];  /* git-daemon */
1297         cld_argv[1] = "--serve";
1298         for (i = 1; i < argc; ++i)
1299                 cld_argv[i+1] = argv[i];
1300         cld_argv[argc+1] = NULL;
1301
1302         return serve(&listen_addr, listen_port, cred);
1303 }