Merge branch 'tb/connect-ipv6-parse-fix' 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 int hostname_lookup_done;
65
66 static void lookup_hostname(void);
67
68 static const char *get_canon_hostname(void)
69 {
70         lookup_hostname();
71         return canon_hostname;
72 }
73
74 static const char *get_ip_address(void)
75 {
76         lookup_hostname();
77         return ip_address;
78 }
79
80 static void logreport(int priority, const char *err, va_list params)
81 {
82         if (log_syslog) {
83                 char buf[1024];
84                 vsnprintf(buf, sizeof(buf), err, params);
85                 syslog(priority, "%s", buf);
86         } else {
87                 /*
88                  * Since stderr is set to buffered mode, the
89                  * logging of different processes will not overlap
90                  * unless they overflow the (rather big) buffers.
91                  */
92                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
93                 vfprintf(stderr, err, params);
94                 fputc('\n', stderr);
95                 fflush(stderr);
96         }
97 }
98
99 __attribute__((format (printf, 1, 2)))
100 static void logerror(const char *err, ...)
101 {
102         va_list params;
103         va_start(params, err);
104         logreport(LOG_ERR, err, params);
105         va_end(params);
106 }
107
108 __attribute__((format (printf, 1, 2)))
109 static void loginfo(const char *err, ...)
110 {
111         va_list params;
112         if (!verbose)
113                 return;
114         va_start(params, err);
115         logreport(LOG_INFO, err, params);
116         va_end(params);
117 }
118
119 static void NORETURN daemon_die(const char *err, va_list params)
120 {
121         logreport(LOG_ERR, err, params);
122         exit(1);
123 }
124
125 static void strbuf_addstr_or_null(struct strbuf *sb, const char *s)
126 {
127         if (s)
128                 strbuf_addstr(sb, s);
129 }
130
131 struct expand_path_context {
132         const char *directory;
133 };
134
135 static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
136 {
137         struct expand_path_context *context = ctx;
138
139         switch (placeholder[0]) {
140         case 'H':
141                 strbuf_addstr_or_null(sb, hostname);
142                 return 1;
143         case 'C':
144                 if (placeholder[1] == 'H') {
145                         strbuf_addstr_or_null(sb, get_canon_hostname());
146                         return 2;
147                 }
148                 break;
149         case 'I':
150                 if (placeholder[1] == 'P') {
151                         strbuf_addstr_or_null(sb, get_ip_address());
152                         return 2;
153                 }
154                 break;
155         case 'P':
156                 strbuf_addstr_or_null(sb, tcp_port);
157                 return 1;
158         case 'D':
159                 strbuf_addstr(sb, context->directory);
160                 return 1;
161         }
162         return 0;
163 }
164
165 static const char *path_ok(const char *directory)
166 {
167         static char rpath[PATH_MAX];
168         static char interp_path[PATH_MAX];
169         const char *path;
170         const char *dir;
171
172         dir = directory;
173
174         if (daemon_avoid_alias(dir)) {
175                 logerror("'%s': aliased", dir);
176                 return NULL;
177         }
178
179         if (*dir == '~') {
180                 if (!user_path) {
181                         logerror("'%s': User-path not allowed", dir);
182                         return NULL;
183                 }
184                 if (*user_path) {
185                         /* Got either "~alice" or "~alice/foo";
186                          * rewrite them to "~alice/%s" or
187                          * "~alice/%s/foo".
188                          */
189                         int namlen, restlen = strlen(dir);
190                         const char *slash = strchr(dir, '/');
191                         if (!slash)
192                                 slash = dir + restlen;
193                         namlen = slash - dir;
194                         restlen -= namlen;
195                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
196                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
197                                  namlen, dir, user_path, restlen, slash);
198                         dir = rpath;
199                 }
200         }
201         else if (interpolated_path && saw_extended_args) {
202                 struct strbuf expanded_path = STRBUF_INIT;
203                 struct expand_path_context context;
204
205                 context.directory = directory;
206
207                 if (*dir != '/') {
208                         /* Allow only absolute */
209                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
210                         return NULL;
211                 }
212
213                 strbuf_expand(&expanded_path, interpolated_path,
214                               expand_path, &context);
215                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
216                 strbuf_release(&expanded_path);
217                 loginfo("Interpolated dir '%s'", interp_path);
218
219                 dir = interp_path;
220         }
221         else if (base_path) {
222                 if (*dir != '/') {
223                         /* Allow only absolute */
224                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
225                         return NULL;
226                 }
227                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
228                 dir = rpath;
229         }
230
231         path = enter_repo(dir, strict_paths);
232         if (!path && base_path && base_path_relaxed) {
233                 /*
234                  * if we fail and base_path_relaxed is enabled, try without
235                  * prefixing the base path
236                  */
237                 dir = directory;
238                 path = enter_repo(dir, strict_paths);
239         }
240
241         if (!path) {
242                 logerror("'%s' does not appear to be a git repository", dir);
243                 return NULL;
244         }
245
246         if ( ok_paths && *ok_paths ) {
247                 char **pp;
248                 int pathlen = strlen(path);
249
250                 /* The validation is done on the paths after enter_repo
251                  * appends optional {.git,.git/.git} and friends, but
252                  * it does not use getcwd().  So if your /pub is
253                  * a symlink to /mnt/pub, you can whitelist /pub and
254                  * do not have to say /mnt/pub.
255                  * Do not say /pub/.
256                  */
257                 for ( pp = ok_paths ; *pp ; pp++ ) {
258                         int len = strlen(*pp);
259                         if (len <= pathlen &&
260                             !memcmp(*pp, path, len) &&
261                             (path[len] == '\0' ||
262                              (!strict_paths && path[len] == '/')))
263                                 return path;
264                 }
265         }
266         else {
267                 /* be backwards compatible */
268                 if (!strict_paths)
269                         return path;
270         }
271
272         logerror("'%s': not in whitelist", path);
273         return NULL;            /* Fallthrough. Deny by default */
274 }
275
276 typedef int (*daemon_service_fn)(void);
277 struct daemon_service {
278         const char *name;
279         const char *config_name;
280         daemon_service_fn fn;
281         int enabled;
282         int overridable;
283 };
284
285 static int daemon_error(const char *dir, const char *msg)
286 {
287         if (!informative_errors)
288                 msg = "access denied or repository not exported";
289         packet_write(1, "ERR %s: %s", msg, dir);
290         return -1;
291 }
292
293 static const char *access_hook;
294
295 static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
296 {
297         struct child_process child = CHILD_PROCESS_INIT;
298         struct strbuf buf = STRBUF_INIT;
299         const char *argv[8];
300         const char **arg = argv;
301         char *eol;
302         int seen_errors = 0;
303
304 #define STRARG(x) ((x) ? (x) : "")
305         *arg++ = access_hook;
306         *arg++ = service->name;
307         *arg++ = path;
308         *arg++ = STRARG(hostname);
309         *arg++ = STRARG(get_canon_hostname());
310         *arg++ = STRARG(get_ip_address());
311         *arg++ = STRARG(tcp_port);
312         *arg = NULL;
313 #undef STRARG
314
315         child.use_shell = 1;
316         child.argv = argv;
317         child.no_stdin = 1;
318         child.no_stderr = 1;
319         child.out = -1;
320         if (start_command(&child)) {
321                 logerror("daemon access hook '%s' failed to start",
322                          access_hook);
323                 goto error_return;
324         }
325         if (strbuf_read(&buf, child.out, 0) < 0) {
326                 logerror("failed to read from pipe to daemon access hook '%s'",
327                          access_hook);
328                 strbuf_reset(&buf);
329                 seen_errors = 1;
330         }
331         if (close(child.out) < 0) {
332                 logerror("failed to close pipe to daemon access hook '%s'",
333                          access_hook);
334                 seen_errors = 1;
335         }
336         if (finish_command(&child))
337                 seen_errors = 1;
338
339         if (!seen_errors) {
340                 strbuf_release(&buf);
341                 return 0;
342         }
343
344 error_return:
345         strbuf_ltrim(&buf);
346         if (!buf.len)
347                 strbuf_addstr(&buf, "service rejected");
348         eol = strchr(buf.buf, '\n');
349         if (eol)
350                 *eol = '\0';
351         errno = EACCES;
352         daemon_error(dir, buf.buf);
353         strbuf_release(&buf);
354         return -1;
355 }
356
357 static int run_service(const char *dir, struct daemon_service *service)
358 {
359         const char *path;
360         int enabled = service->enabled;
361         struct strbuf var = STRBUF_INIT;
362
363         loginfo("Request %s for '%s'", service->name, dir);
364
365         if (!enabled && !service->overridable) {
366                 logerror("'%s': service not enabled.", service->name);
367                 errno = EACCES;
368                 return daemon_error(dir, "service not enabled");
369         }
370
371         if (!(path = path_ok(dir)))
372                 return daemon_error(dir, "no such repository");
373
374         /*
375          * Security on the cheap.
376          *
377          * We want a readable HEAD, usable "objects" directory, and
378          * a "git-daemon-export-ok" flag that says that the other side
379          * is ok with us doing this.
380          *
381          * path_ok() uses enter_repo() and does whitelist checking.
382          * We only need to make sure the repository is exported.
383          */
384
385         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
386                 logerror("'%s': repository not exported.", path);
387                 errno = EACCES;
388                 return daemon_error(dir, "repository not exported");
389         }
390
391         if (service->overridable) {
392                 strbuf_addf(&var, "daemon.%s", service->config_name);
393                 git_config_get_bool(var.buf, &enabled);
394                 strbuf_release(&var);
395         }
396         if (!enabled) {
397                 logerror("'%s': service not enabled for '%s'",
398                          service->name, path);
399                 errno = EACCES;
400                 return daemon_error(dir, "service not enabled");
401         }
402
403         /*
404          * Optionally, a hook can choose to deny access to the
405          * repository depending on the phase of the moon.
406          */
407         if (access_hook && run_access_hook(service, dir, path))
408                 return -1;
409
410         /*
411          * We'll ignore SIGTERM from now on, we have a
412          * good client.
413          */
414         signal(SIGTERM, SIG_IGN);
415
416         return service->fn();
417 }
418
419 static void copy_to_log(int fd)
420 {
421         struct strbuf line = STRBUF_INIT;
422         FILE *fp;
423
424         fp = fdopen(fd, "r");
425         if (fp == NULL) {
426                 logerror("fdopen of error channel failed");
427                 close(fd);
428                 return;
429         }
430
431         while (strbuf_getline(&line, fp, '\n') != EOF) {
432                 logerror("%s", line.buf);
433                 strbuf_setlen(&line, 0);
434         }
435
436         strbuf_release(&line);
437         fclose(fp);
438 }
439
440 static int run_service_command(const char **argv)
441 {
442         struct child_process cld = CHILD_PROCESS_INIT;
443
444         cld.argv = argv;
445         cld.git_cmd = 1;
446         cld.err = -1;
447         if (start_command(&cld))
448                 return -1;
449
450         close(0);
451         close(1);
452
453         copy_to_log(cld.err);
454
455         return finish_command(&cld);
456 }
457
458 static int upload_pack(void)
459 {
460         /* Timeout as string */
461         char timeout_buf[64];
462         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
463
464         argv[2] = timeout_buf;
465
466         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
467         return run_service_command(argv);
468 }
469
470 static int upload_archive(void)
471 {
472         static const char *argv[] = { "upload-archive", ".", NULL };
473         return run_service_command(argv);
474 }
475
476 static int receive_pack(void)
477 {
478         static const char *argv[] = { "receive-pack", ".", NULL };
479         return run_service_command(argv);
480 }
481
482 static struct daemon_service daemon_service[] = {
483         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
484         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
485         { "receive-pack", "receivepack", receive_pack, 0, 1 },
486 };
487
488 static void enable_service(const char *name, int ena)
489 {
490         int i;
491         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
492                 if (!strcmp(daemon_service[i].name, name)) {
493                         daemon_service[i].enabled = ena;
494                         return;
495                 }
496         }
497         die("No such service %s", name);
498 }
499
500 static void make_service_overridable(const char *name, int ena)
501 {
502         int i;
503         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
504                 if (!strcmp(daemon_service[i].name, name)) {
505                         daemon_service[i].overridable = ena;
506                         return;
507                 }
508         }
509         die("No such service %s", name);
510 }
511
512 static void parse_host_and_port(char *hostport, char **host,
513         char **port)
514 {
515         if (*hostport == '[') {
516                 char *end;
517
518                 end = strchr(hostport, ']');
519                 if (!end)
520                         die("Invalid request ('[' without ']')");
521                 *end = '\0';
522                 *host = hostport + 1;
523                 if (!end[1])
524                         *port = NULL;
525                 else if (end[1] == ':')
526                         *port = end + 2;
527                 else
528                         die("Garbage after end of host part");
529         } else {
530                 *host = hostport;
531                 *port = strrchr(hostport, ':');
532                 if (*port) {
533                         **port = '\0';
534                         ++*port;
535                 }
536         }
537 }
538
539 /*
540  * Sanitize a string from the client so that it's OK to be inserted into a
541  * filesystem path. Specifically, we disallow slashes, runs of "..", and
542  * trailing and leading dots, which means that the client cannot escape
543  * our base path via ".." traversal.
544  */
545 static void sanitize_client_strbuf(struct strbuf *out, const char *in)
546 {
547         for (; *in; in++) {
548                 if (*in == '/')
549                         continue;
550                 if (*in == '.' && (!out->len || out->buf[out->len - 1] == '.'))
551                         continue;
552                 strbuf_addch(out, *in);
553         }
554
555         while (out->len && out->buf[out->len - 1] == '.')
556                 strbuf_setlen(out, out->len - 1);
557 }
558
559 static char *sanitize_client(const char *in)
560 {
561         struct strbuf out = STRBUF_INIT;
562         sanitize_client_strbuf(&out, in);
563         return strbuf_detach(&out, NULL);
564 }
565
566 /*
567  * Like sanitize_client, but we also perform any canonicalization
568  * to make life easier on the admin.
569  */
570 static char *canonicalize_client(const char *in)
571 {
572         struct strbuf out = STRBUF_INIT;
573         sanitize_client_strbuf(&out, in);
574         strbuf_tolower(&out);
575         return strbuf_detach(&out, NULL);
576 }
577
578 /*
579  * Read the host as supplied by the client connection.
580  */
581 static void parse_host_arg(char *extra_args, int buflen)
582 {
583         char *val;
584         int vallen;
585         char *end = extra_args + buflen;
586
587         if (extra_args < end && *extra_args) {
588                 saw_extended_args = 1;
589                 if (strncasecmp("host=", extra_args, 5) == 0) {
590                         val = extra_args + 5;
591                         vallen = strlen(val) + 1;
592                         if (*val) {
593                                 /* Split <host>:<port> at colon. */
594                                 char *host;
595                                 char *port;
596                                 parse_host_and_port(val, &host, &port);
597                                 if (port) {
598                                         free(tcp_port);
599                                         tcp_port = sanitize_client(port);
600                                 }
601                                 free(hostname);
602                                 hostname = canonicalize_client(host);
603                                 hostname_lookup_done = 0;
604                         }
605
606                         /* On to the next one */
607                         extra_args = val + vallen;
608                 }
609                 if (extra_args < end && *extra_args)
610                         die("Invalid request");
611         }
612 }
613
614 /*
615  * Locate canonical hostname and its IP address.
616  */
617 static void lookup_hostname(void)
618 {
619         if (!hostname_lookup_done && hostname) {
620 #ifndef NO_IPV6
621                 struct addrinfo hints;
622                 struct addrinfo *ai;
623                 int gai;
624                 static char addrbuf[HOST_NAME_MAX + 1];
625
626                 memset(&hints, 0, sizeof(hints));
627                 hints.ai_flags = AI_CANONNAME;
628
629                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
630                 if (!gai) {
631                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
632
633                         inet_ntop(AF_INET, &sin_addr->sin_addr,
634                                   addrbuf, sizeof(addrbuf));
635                         free(ip_address);
636                         ip_address = xstrdup(addrbuf);
637
638                         free(canon_hostname);
639                         canon_hostname = ai->ai_canonname ?
640                                 sanitize_client(ai->ai_canonname) :
641                                 xstrdup(ip_address);
642
643                         freeaddrinfo(ai);
644                 }
645 #else
646                 struct hostent *hent;
647                 struct sockaddr_in sa;
648                 char **ap;
649                 static char addrbuf[HOST_NAME_MAX + 1];
650
651                 hent = gethostbyname(hostname);
652                 if (hent) {
653                         ap = hent->h_addr_list;
654                         memset(&sa, 0, sizeof sa);
655                         sa.sin_family = hent->h_addrtype;
656                         sa.sin_port = htons(0);
657                         memcpy(&sa.sin_addr, *ap, hent->h_length);
658
659                         inet_ntop(hent->h_addrtype, &sa.sin_addr,
660                                   addrbuf, sizeof(addrbuf));
661
662                         free(canon_hostname);
663                         canon_hostname = sanitize_client(hent->h_name);
664                         free(ip_address);
665                         ip_address = xstrdup(addrbuf);
666                 }
667 #endif
668                 hostname_lookup_done = 1;
669         }
670 }
671
672
673 static int execute(void)
674 {
675         char *line = packet_buffer;
676         int pktlen, len, i;
677         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
678
679         if (addr)
680                 loginfo("Connection from %s:%s", addr, port);
681
682         alarm(init_timeout ? init_timeout : timeout);
683         pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
684         alarm(0);
685
686         len = strlen(line);
687         if (pktlen != len)
688                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
689                         (int) pktlen - len,
690                         (int) pktlen - len, line + len + 1);
691         if (len && line[len-1] == '\n') {
692                 line[--len] = 0;
693                 pktlen--;
694         }
695
696         free(hostname);
697         free(canon_hostname);
698         free(ip_address);
699         free(tcp_port);
700         hostname = canon_hostname = ip_address = tcp_port = NULL;
701
702         if (len != pktlen)
703                 parse_host_arg(line + len + 1, pktlen - len - 1);
704
705         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
706                 struct daemon_service *s = &(daemon_service[i]);
707                 const char *arg;
708
709                 if (skip_prefix(line, "git-", &arg) &&
710                     skip_prefix(arg, s->name, &arg) &&
711                     *arg++ == ' ') {
712                         /*
713                          * Note: The directory here is probably context sensitive,
714                          * and might depend on the actual service being performed.
715                          */
716                         return run_service(arg, s);
717                 }
718         }
719
720         logerror("Protocol error: '%s'", line);
721         return -1;
722 }
723
724 static int addrcmp(const struct sockaddr_storage *s1,
725     const struct sockaddr_storage *s2)
726 {
727         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
728         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
729
730         if (sa1->sa_family != sa2->sa_family)
731                 return sa1->sa_family - sa2->sa_family;
732         if (sa1->sa_family == AF_INET)
733                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
734                     &((struct sockaddr_in *)s2)->sin_addr,
735                     sizeof(struct in_addr));
736 #ifndef NO_IPV6
737         if (sa1->sa_family == AF_INET6)
738                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
739                     &((struct sockaddr_in6 *)s2)->sin6_addr,
740                     sizeof(struct in6_addr));
741 #endif
742         return 0;
743 }
744
745 static int max_connections = 32;
746
747 static unsigned int live_children;
748
749 static struct child {
750         struct child *next;
751         struct child_process cld;
752         struct sockaddr_storage address;
753 } *firstborn;
754
755 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
756 {
757         struct child *newborn, **cradle;
758
759         newborn = xcalloc(1, sizeof(*newborn));
760         live_children++;
761         memcpy(&newborn->cld, cld, sizeof(*cld));
762         memcpy(&newborn->address, addr, addrlen);
763         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
764                 if (!addrcmp(&(*cradle)->address, &newborn->address))
765                         break;
766         newborn->next = *cradle;
767         *cradle = newborn;
768 }
769
770 /*
771  * This gets called if the number of connections grows
772  * past "max_connections".
773  *
774  * We kill the newest connection from a duplicate IP.
775  */
776 static void kill_some_child(void)
777 {
778         const struct child *blanket, *next;
779
780         if (!(blanket = firstborn))
781                 return;
782
783         for (; (next = blanket->next); blanket = next)
784                 if (!addrcmp(&blanket->address, &next->address)) {
785                         kill(blanket->cld.pid, SIGTERM);
786                         break;
787                 }
788 }
789
790 static void check_dead_children(void)
791 {
792         int status;
793         pid_t pid;
794
795         struct child **cradle, *blanket;
796         for (cradle = &firstborn; (blanket = *cradle);)
797                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
798                         const char *dead = "";
799                         if (status)
800                                 dead = " (with error)";
801                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
802
803                         /* remove the child */
804                         *cradle = blanket->next;
805                         live_children--;
806                         free(blanket);
807                 } else
808                         cradle = &blanket->next;
809 }
810
811 static char **cld_argv;
812 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
813 {
814         struct child_process cld = CHILD_PROCESS_INIT;
815         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
816         char *env[] = { addrbuf, portbuf, NULL };
817
818         if (max_connections && live_children >= max_connections) {
819                 kill_some_child();
820                 sleep(1);  /* give it some time to die */
821                 check_dead_children();
822                 if (live_children >= max_connections) {
823                         close(incoming);
824                         logerror("Too many children, dropping connection");
825                         return;
826                 }
827         }
828
829         if (addr->sa_family == AF_INET) {
830                 struct sockaddr_in *sin_addr = (void *) addr;
831                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
832                     sizeof(addrbuf) - 12);
833                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
834                     ntohs(sin_addr->sin_port));
835 #ifndef NO_IPV6
836         } else if (addr->sa_family == AF_INET6) {
837                 struct sockaddr_in6 *sin6_addr = (void *) addr;
838
839                 char *buf = addrbuf + 12;
840                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
841                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
842                     sizeof(addrbuf) - 13);
843                 strcat(buf, "]");
844
845                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
846                     ntohs(sin6_addr->sin6_port));
847 #endif
848         }
849
850         cld.env = (const char **)env;
851         cld.argv = (const char **)cld_argv;
852         cld.in = incoming;
853         cld.out = dup(incoming);
854
855         if (start_command(&cld))
856                 logerror("unable to fork");
857         else
858                 add_child(&cld, addr, addrlen);
859 }
860
861 static void child_handler(int signo)
862 {
863         /*
864          * Otherwise empty handler because systemcalls will get interrupted
865          * upon signal receipt
866          * SysV needs the handler to be rearmed
867          */
868         signal(SIGCHLD, child_handler);
869 }
870
871 static int set_reuse_addr(int sockfd)
872 {
873         int on = 1;
874
875         if (!reuseaddr)
876                 return 0;
877         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
878                           &on, sizeof(on));
879 }
880
881 struct socketlist {
882         int *list;
883         size_t nr;
884         size_t alloc;
885 };
886
887 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
888 {
889 #ifdef NO_IPV6
890         static char ip[INET_ADDRSTRLEN];
891 #else
892         static char ip[INET6_ADDRSTRLEN];
893 #endif
894
895         switch (family) {
896 #ifndef NO_IPV6
897         case AF_INET6:
898                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
899                 break;
900 #endif
901         case AF_INET:
902                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
903                 break;
904         default:
905                 strcpy(ip, "<unknown>");
906         }
907         return ip;
908 }
909
910 #ifndef NO_IPV6
911
912 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
913 {
914         int socknum = 0;
915         char pbuf[NI_MAXSERV];
916         struct addrinfo hints, *ai0, *ai;
917         int gai;
918         long flags;
919
920         sprintf(pbuf, "%d", listen_port);
921         memset(&hints, 0, sizeof(hints));
922         hints.ai_family = AF_UNSPEC;
923         hints.ai_socktype = SOCK_STREAM;
924         hints.ai_protocol = IPPROTO_TCP;
925         hints.ai_flags = AI_PASSIVE;
926
927         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
928         if (gai) {
929                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
930                 return 0;
931         }
932
933         for (ai = ai0; ai; ai = ai->ai_next) {
934                 int sockfd;
935
936                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
937                 if (sockfd < 0)
938                         continue;
939                 if (sockfd >= FD_SETSIZE) {
940                         logerror("Socket descriptor too large");
941                         close(sockfd);
942                         continue;
943                 }
944
945 #ifdef IPV6_V6ONLY
946                 if (ai->ai_family == AF_INET6) {
947                         int on = 1;
948                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
949                                    &on, sizeof(on));
950                         /* Note: error is not fatal */
951                 }
952 #endif
953
954                 if (set_reuse_addr(sockfd)) {
955                         logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
956                         close(sockfd);
957                         continue;
958                 }
959
960                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
961                         logerror("Could not bind to %s: %s",
962                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
963                                  strerror(errno));
964                         close(sockfd);
965                         continue;       /* not fatal */
966                 }
967                 if (listen(sockfd, 5) < 0) {
968                         logerror("Could not listen to %s: %s",
969                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
970                                  strerror(errno));
971                         close(sockfd);
972                         continue;       /* not fatal */
973                 }
974
975                 flags = fcntl(sockfd, F_GETFD, 0);
976                 if (flags >= 0)
977                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
978
979                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
980                 socklist->list[socklist->nr++] = sockfd;
981                 socknum++;
982         }
983
984         freeaddrinfo(ai0);
985
986         return socknum;
987 }
988
989 #else /* NO_IPV6 */
990
991 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
992 {
993         struct sockaddr_in sin;
994         int sockfd;
995         long flags;
996
997         memset(&sin, 0, sizeof sin);
998         sin.sin_family = AF_INET;
999         sin.sin_port = htons(listen_port);
1000
1001         if (listen_addr) {
1002                 /* Well, host better be an IP address here. */
1003                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
1004                         return 0;
1005         } else {
1006                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
1007         }
1008
1009         sockfd = socket(AF_INET, SOCK_STREAM, 0);
1010         if (sockfd < 0)
1011                 return 0;
1012
1013         if (set_reuse_addr(sockfd)) {
1014                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
1015                 close(sockfd);
1016                 return 0;
1017         }
1018
1019         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
1020                 logerror("Could not bind to %s: %s",
1021                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1022                          strerror(errno));
1023                 close(sockfd);
1024                 return 0;
1025         }
1026
1027         if (listen(sockfd, 5) < 0) {
1028                 logerror("Could not listen to %s: %s",
1029                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1030                          strerror(errno));
1031                 close(sockfd);
1032                 return 0;
1033         }
1034
1035         flags = fcntl(sockfd, F_GETFD, 0);
1036         if (flags >= 0)
1037                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1038
1039         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1040         socklist->list[socklist->nr++] = sockfd;
1041         return 1;
1042 }
1043
1044 #endif
1045
1046 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
1047 {
1048         if (!listen_addr->nr)
1049                 setup_named_sock(NULL, listen_port, socklist);
1050         else {
1051                 int i, socknum;
1052                 for (i = 0; i < listen_addr->nr; i++) {
1053                         socknum = setup_named_sock(listen_addr->items[i].string,
1054                                                    listen_port, socklist);
1055
1056                         if (socknum == 0)
1057                                 logerror("unable to allocate any listen sockets for host %s on port %u",
1058                                          listen_addr->items[i].string, listen_port);
1059                 }
1060         }
1061 }
1062
1063 static int service_loop(struct socketlist *socklist)
1064 {
1065         struct pollfd *pfd;
1066         int i;
1067
1068         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
1069
1070         for (i = 0; i < socklist->nr; i++) {
1071                 pfd[i].fd = socklist->list[i];
1072                 pfd[i].events = POLLIN;
1073         }
1074
1075         signal(SIGCHLD, child_handler);
1076
1077         for (;;) {
1078                 int i;
1079
1080                 check_dead_children();
1081
1082                 if (poll(pfd, socklist->nr, -1) < 0) {
1083                         if (errno != EINTR) {
1084                                 logerror("Poll failed, resuming: %s",
1085                                       strerror(errno));
1086                                 sleep(1);
1087                         }
1088                         continue;
1089                 }
1090
1091                 for (i = 0; i < socklist->nr; i++) {
1092                         if (pfd[i].revents & POLLIN) {
1093                                 union {
1094                                         struct sockaddr sa;
1095                                         struct sockaddr_in sai;
1096 #ifndef NO_IPV6
1097                                         struct sockaddr_in6 sai6;
1098 #endif
1099                                 } ss;
1100                                 socklen_t sslen = sizeof(ss);
1101                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1102                                 if (incoming < 0) {
1103                                         switch (errno) {
1104                                         case EAGAIN:
1105                                         case EINTR:
1106                                         case ECONNABORTED:
1107                                                 continue;
1108                                         default:
1109                                                 die_errno("accept returned");
1110                                         }
1111                                 }
1112                                 handle(incoming, &ss.sa, sslen);
1113                         }
1114                 }
1115         }
1116 }
1117
1118 #ifdef NO_POSIX_GOODIES
1119
1120 struct credentials;
1121
1122 static void drop_privileges(struct credentials *cred)
1123 {
1124         /* nothing */
1125 }
1126
1127 static struct credentials *prepare_credentials(const char *user_name,
1128     const char *group_name)
1129 {
1130         die("--user not supported on this platform");
1131 }
1132
1133 #else
1134
1135 struct credentials {
1136         struct passwd *pass;
1137         gid_t gid;
1138 };
1139
1140 static void drop_privileges(struct credentials *cred)
1141 {
1142         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1143             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1144                 die("cannot drop privileges");
1145 }
1146
1147 static struct credentials *prepare_credentials(const char *user_name,
1148     const char *group_name)
1149 {
1150         static struct credentials c;
1151
1152         c.pass = getpwnam(user_name);
1153         if (!c.pass)
1154                 die("user not found - %s", user_name);
1155
1156         if (!group_name)
1157                 c.gid = c.pass->pw_gid;
1158         else {
1159                 struct group *group = getgrnam(group_name);
1160                 if (!group)
1161                         die("group not found - %s", group_name);
1162
1163                 c.gid = group->gr_gid;
1164         }
1165
1166         return &c;
1167 }
1168 #endif
1169
1170 static void store_pid(const char *path)
1171 {
1172         FILE *f = fopen(path, "w");
1173         if (!f)
1174                 die_errno("cannot open pid file '%s'", path);
1175         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1176                 die_errno("failed to write pid file '%s'", path);
1177 }
1178
1179 static int serve(struct string_list *listen_addr, int listen_port,
1180     struct credentials *cred)
1181 {
1182         struct socketlist socklist = { NULL, 0, 0 };
1183
1184         socksetup(listen_addr, listen_port, &socklist);
1185         if (socklist.nr == 0)
1186                 die("unable to allocate any listen sockets on port %u",
1187                     listen_port);
1188
1189         drop_privileges(cred);
1190
1191         loginfo("Ready to rumble");
1192
1193         return service_loop(&socklist);
1194 }
1195
1196 int main(int argc, char **argv)
1197 {
1198         int listen_port = 0;
1199         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1200         int serve_mode = 0, inetd_mode = 0;
1201         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1202         int detach = 0;
1203         struct credentials *cred = NULL;
1204         int i;
1205
1206         git_setup_gettext();
1207
1208         git_extract_argv0_path(argv[0]);
1209
1210         for (i = 1; i < argc; i++) {
1211                 char *arg = argv[i];
1212                 const char *v;
1213
1214                 if (skip_prefix(arg, "--listen=", &v)) {
1215                         string_list_append(&listen_addr, xstrdup_tolower(v));
1216                         continue;
1217                 }
1218                 if (skip_prefix(arg, "--port=", &v)) {
1219                         char *end;
1220                         unsigned long n;
1221                         n = strtoul(v, &end, 0);
1222                         if (*v && !*end) {
1223                                 listen_port = n;
1224                                 continue;
1225                         }
1226                 }
1227                 if (!strcmp(arg, "--serve")) {
1228                         serve_mode = 1;
1229                         continue;
1230                 }
1231                 if (!strcmp(arg, "--inetd")) {
1232                         inetd_mode = 1;
1233                         log_syslog = 1;
1234                         continue;
1235                 }
1236                 if (!strcmp(arg, "--verbose")) {
1237                         verbose = 1;
1238                         continue;
1239                 }
1240                 if (!strcmp(arg, "--syslog")) {
1241                         log_syslog = 1;
1242                         continue;
1243                 }
1244                 if (!strcmp(arg, "--export-all")) {
1245                         export_all_trees = 1;
1246                         continue;
1247                 }
1248                 if (skip_prefix(arg, "--access-hook=", &v)) {
1249                         access_hook = v;
1250                         continue;
1251                 }
1252                 if (skip_prefix(arg, "--timeout=", &v)) {
1253                         timeout = atoi(v);
1254                         continue;
1255                 }
1256                 if (skip_prefix(arg, "--init-timeout=", &v)) {
1257                         init_timeout = atoi(v);
1258                         continue;
1259                 }
1260                 if (skip_prefix(arg, "--max-connections=", &v)) {
1261                         max_connections = atoi(v);
1262                         if (max_connections < 0)
1263                                 max_connections = 0;            /* unlimited */
1264                         continue;
1265                 }
1266                 if (!strcmp(arg, "--strict-paths")) {
1267                         strict_paths = 1;
1268                         continue;
1269                 }
1270                 if (skip_prefix(arg, "--base-path=", &v)) {
1271                         base_path = v;
1272                         continue;
1273                 }
1274                 if (!strcmp(arg, "--base-path-relaxed")) {
1275                         base_path_relaxed = 1;
1276                         continue;
1277                 }
1278                 if (skip_prefix(arg, "--interpolated-path=", &v)) {
1279                         interpolated_path = v;
1280                         continue;
1281                 }
1282                 if (!strcmp(arg, "--reuseaddr")) {
1283                         reuseaddr = 1;
1284                         continue;
1285                 }
1286                 if (!strcmp(arg, "--user-path")) {
1287                         user_path = "";
1288                         continue;
1289                 }
1290                 if (skip_prefix(arg, "--user-path=", &v)) {
1291                         user_path = v;
1292                         continue;
1293                 }
1294                 if (skip_prefix(arg, "--pid-file=", &v)) {
1295                         pid_file = v;
1296                         continue;
1297                 }
1298                 if (!strcmp(arg, "--detach")) {
1299                         detach = 1;
1300                         log_syslog = 1;
1301                         continue;
1302                 }
1303                 if (skip_prefix(arg, "--user=", &v)) {
1304                         user_name = v;
1305                         continue;
1306                 }
1307                 if (skip_prefix(arg, "--group=", &v)) {
1308                         group_name = v;
1309                         continue;
1310                 }
1311                 if (skip_prefix(arg, "--enable=", &v)) {
1312                         enable_service(v, 1);
1313                         continue;
1314                 }
1315                 if (skip_prefix(arg, "--disable=", &v)) {
1316                         enable_service(v, 0);
1317                         continue;
1318                 }
1319                 if (skip_prefix(arg, "--allow-override=", &v)) {
1320                         make_service_overridable(v, 1);
1321                         continue;
1322                 }
1323                 if (skip_prefix(arg, "--forbid-override=", &v)) {
1324                         make_service_overridable(v, 0);
1325                         continue;
1326                 }
1327                 if (!strcmp(arg, "--informative-errors")) {
1328                         informative_errors = 1;
1329                         continue;
1330                 }
1331                 if (!strcmp(arg, "--no-informative-errors")) {
1332                         informative_errors = 0;
1333                         continue;
1334                 }
1335                 if (!strcmp(arg, "--")) {
1336                         ok_paths = &argv[i+1];
1337                         break;
1338                 } else if (arg[0] != '-') {
1339                         ok_paths = &argv[i];
1340                         break;
1341                 }
1342
1343                 usage(daemon_usage);
1344         }
1345
1346         if (log_syslog) {
1347                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1348                 set_die_routine(daemon_die);
1349         } else
1350                 /* avoid splitting a message in the middle */
1351                 setvbuf(stderr, NULL, _IOFBF, 4096);
1352
1353         if (inetd_mode && (detach || group_name || user_name))
1354                 die("--detach, --user and --group are incompatible with --inetd");
1355
1356         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1357                 die("--listen= and --port= are incompatible with --inetd");
1358         else if (listen_port == 0)
1359                 listen_port = DEFAULT_GIT_PORT;
1360
1361         if (group_name && !user_name)
1362                 die("--group supplied without --user");
1363
1364         if (user_name)
1365                 cred = prepare_credentials(user_name, group_name);
1366
1367         if (strict_paths && (!ok_paths || !*ok_paths))
1368                 die("option --strict-paths requires a whitelist");
1369
1370         if (base_path && !is_directory(base_path))
1371                 die("base-path '%s' does not exist or is not a directory",
1372                     base_path);
1373
1374         if (inetd_mode) {
1375                 if (!freopen("/dev/null", "w", stderr))
1376                         die_errno("failed to redirect stderr to /dev/null");
1377         }
1378
1379         if (inetd_mode || serve_mode)
1380                 return execute();
1381
1382         if (detach) {
1383                 if (daemonize())
1384                         die("--detach not supported on this platform");
1385         } else
1386                 sanitize_stdfds();
1387
1388         if (pid_file)
1389                 store_pid(pid_file);
1390
1391         /* prepare argv for serving-processes */
1392         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1393         cld_argv[0] = argv[0];  /* git-daemon */
1394         cld_argv[1] = "--serve";
1395         for (i = 1; i < argc; ++i)
1396                 cld_argv[i+1] = argv[i];
1397         cld_argv[argc+1] = NULL;
1398
1399         return serve(&listen_addr, listen_port, cred);
1400 }