Sync with 2.1.2
[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
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 #endif
571         }
572 }
573
574
575 static int execute(void)
576 {
577         char *line = packet_buffer;
578         int pktlen, len, i;
579         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
580
581         if (addr)
582                 loginfo("Connection from %s:%s", addr, port);
583
584         alarm(init_timeout ? init_timeout : timeout);
585         pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
586         alarm(0);
587
588         len = strlen(line);
589         if (pktlen != len)
590                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
591                         (int) pktlen - len,
592                         (int) pktlen - len, line + len + 1);
593         if (len && line[len-1] == '\n') {
594                 line[--len] = 0;
595                 pktlen--;
596         }
597
598         free(hostname);
599         free(canon_hostname);
600         free(ip_address);
601         free(tcp_port);
602         hostname = canon_hostname = ip_address = tcp_port = NULL;
603
604         if (len != pktlen)
605                 parse_host_arg(line + len + 1, pktlen - len - 1);
606
607         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
608                 struct daemon_service *s = &(daemon_service[i]);
609                 const char *arg;
610
611                 if (skip_prefix(line, "git-", &arg) &&
612                     skip_prefix(arg, s->name, &arg) &&
613                     *arg++ == ' ') {
614                         /*
615                          * Note: The directory here is probably context sensitive,
616                          * and might depend on the actual service being performed.
617                          */
618                         return run_service(arg, s);
619                 }
620         }
621
622         logerror("Protocol error: '%s'", line);
623         return -1;
624 }
625
626 static int addrcmp(const struct sockaddr_storage *s1,
627     const struct sockaddr_storage *s2)
628 {
629         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
630         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
631
632         if (sa1->sa_family != sa2->sa_family)
633                 return sa1->sa_family - sa2->sa_family;
634         if (sa1->sa_family == AF_INET)
635                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
636                     &((struct sockaddr_in *)s2)->sin_addr,
637                     sizeof(struct in_addr));
638 #ifndef NO_IPV6
639         if (sa1->sa_family == AF_INET6)
640                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
641                     &((struct sockaddr_in6 *)s2)->sin6_addr,
642                     sizeof(struct in6_addr));
643 #endif
644         return 0;
645 }
646
647 static int max_connections = 32;
648
649 static unsigned int live_children;
650
651 static struct child {
652         struct child *next;
653         struct child_process cld;
654         struct sockaddr_storage address;
655 } *firstborn;
656
657 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
658 {
659         struct child *newborn, **cradle;
660
661         newborn = xcalloc(1, sizeof(*newborn));
662         live_children++;
663         memcpy(&newborn->cld, cld, sizeof(*cld));
664         memcpy(&newborn->address, addr, addrlen);
665         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
666                 if (!addrcmp(&(*cradle)->address, &newborn->address))
667                         break;
668         newborn->next = *cradle;
669         *cradle = newborn;
670 }
671
672 /*
673  * This gets called if the number of connections grows
674  * past "max_connections".
675  *
676  * We kill the newest connection from a duplicate IP.
677  */
678 static void kill_some_child(void)
679 {
680         const struct child *blanket, *next;
681
682         if (!(blanket = firstborn))
683                 return;
684
685         for (; (next = blanket->next); blanket = next)
686                 if (!addrcmp(&blanket->address, &next->address)) {
687                         kill(blanket->cld.pid, SIGTERM);
688                         break;
689                 }
690 }
691
692 static void check_dead_children(void)
693 {
694         int status;
695         pid_t pid;
696
697         struct child **cradle, *blanket;
698         for (cradle = &firstborn; (blanket = *cradle);)
699                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
700                         const char *dead = "";
701                         if (status)
702                                 dead = " (with error)";
703                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
704
705                         /* remove the child */
706                         *cradle = blanket->next;
707                         live_children--;
708                         free(blanket);
709                 } else
710                         cradle = &blanket->next;
711 }
712
713 static char **cld_argv;
714 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
715 {
716         struct child_process cld = CHILD_PROCESS_INIT;
717         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
718         char *env[] = { addrbuf, portbuf, NULL };
719
720         if (max_connections && live_children >= max_connections) {
721                 kill_some_child();
722                 sleep(1);  /* give it some time to die */
723                 check_dead_children();
724                 if (live_children >= max_connections) {
725                         close(incoming);
726                         logerror("Too many children, dropping connection");
727                         return;
728                 }
729         }
730
731         if (addr->sa_family == AF_INET) {
732                 struct sockaddr_in *sin_addr = (void *) addr;
733                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
734                     sizeof(addrbuf) - 12);
735                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
736                     ntohs(sin_addr->sin_port));
737 #ifndef NO_IPV6
738         } else if (addr->sa_family == AF_INET6) {
739                 struct sockaddr_in6 *sin6_addr = (void *) addr;
740
741                 char *buf = addrbuf + 12;
742                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
743                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
744                     sizeof(addrbuf) - 13);
745                 strcat(buf, "]");
746
747                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
748                     ntohs(sin6_addr->sin6_port));
749 #endif
750         }
751
752         cld.env = (const char **)env;
753         cld.argv = (const char **)cld_argv;
754         cld.in = incoming;
755         cld.out = dup(incoming);
756
757         if (start_command(&cld))
758                 logerror("unable to fork");
759         else
760                 add_child(&cld, addr, addrlen);
761 }
762
763 static void child_handler(int signo)
764 {
765         /*
766          * Otherwise empty handler because systemcalls will get interrupted
767          * upon signal receipt
768          * SysV needs the handler to be rearmed
769          */
770         signal(SIGCHLD, child_handler);
771 }
772
773 static int set_reuse_addr(int sockfd)
774 {
775         int on = 1;
776
777         if (!reuseaddr)
778                 return 0;
779         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
780                           &on, sizeof(on));
781 }
782
783 struct socketlist {
784         int *list;
785         size_t nr;
786         size_t alloc;
787 };
788
789 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
790 {
791 #ifdef NO_IPV6
792         static char ip[INET_ADDRSTRLEN];
793 #else
794         static char ip[INET6_ADDRSTRLEN];
795 #endif
796
797         switch (family) {
798 #ifndef NO_IPV6
799         case AF_INET6:
800                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
801                 break;
802 #endif
803         case AF_INET:
804                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
805                 break;
806         default:
807                 strcpy(ip, "<unknown>");
808         }
809         return ip;
810 }
811
812 #ifndef NO_IPV6
813
814 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
815 {
816         int socknum = 0;
817         int maxfd = -1;
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                 if (maxfd < sockfd)
887                         maxfd = sockfd;
888         }
889
890         freeaddrinfo(ai0);
891
892         return socknum;
893 }
894
895 #else /* NO_IPV6 */
896
897 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
898 {
899         struct sockaddr_in sin;
900         int sockfd;
901         long flags;
902
903         memset(&sin, 0, sizeof sin);
904         sin.sin_family = AF_INET;
905         sin.sin_port = htons(listen_port);
906
907         if (listen_addr) {
908                 /* Well, host better be an IP address here. */
909                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
910                         return 0;
911         } else {
912                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
913         }
914
915         sockfd = socket(AF_INET, SOCK_STREAM, 0);
916         if (sockfd < 0)
917                 return 0;
918
919         if (set_reuse_addr(sockfd)) {
920                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
921                 close(sockfd);
922                 return 0;
923         }
924
925         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
926                 logerror("Could not listen to %s: %s",
927                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
928                          strerror(errno));
929                 close(sockfd);
930                 return 0;
931         }
932
933         if (listen(sockfd, 5) < 0) {
934                 logerror("Could not listen to %s: %s",
935                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
936                          strerror(errno));
937                 close(sockfd);
938                 return 0;
939         }
940
941         flags = fcntl(sockfd, F_GETFD, 0);
942         if (flags >= 0)
943                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
944
945         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
946         socklist->list[socklist->nr++] = sockfd;
947         return 1;
948 }
949
950 #endif
951
952 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
953 {
954         if (!listen_addr->nr)
955                 setup_named_sock(NULL, listen_port, socklist);
956         else {
957                 int i, socknum;
958                 for (i = 0; i < listen_addr->nr; i++) {
959                         socknum = setup_named_sock(listen_addr->items[i].string,
960                                                    listen_port, socklist);
961
962                         if (socknum == 0)
963                                 logerror("unable to allocate any listen sockets for host %s on port %u",
964                                          listen_addr->items[i].string, listen_port);
965                 }
966         }
967 }
968
969 static int service_loop(struct socketlist *socklist)
970 {
971         struct pollfd *pfd;
972         int i;
973
974         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
975
976         for (i = 0; i < socklist->nr; i++) {
977                 pfd[i].fd = socklist->list[i];
978                 pfd[i].events = POLLIN;
979         }
980
981         signal(SIGCHLD, child_handler);
982
983         for (;;) {
984                 int i;
985
986                 check_dead_children();
987
988                 if (poll(pfd, socklist->nr, -1) < 0) {
989                         if (errno != EINTR) {
990                                 logerror("Poll failed, resuming: %s",
991                                       strerror(errno));
992                                 sleep(1);
993                         }
994                         continue;
995                 }
996
997                 for (i = 0; i < socklist->nr; i++) {
998                         if (pfd[i].revents & POLLIN) {
999                                 union {
1000                                         struct sockaddr sa;
1001                                         struct sockaddr_in sai;
1002 #ifndef NO_IPV6
1003                                         struct sockaddr_in6 sai6;
1004 #endif
1005                                 } ss;
1006                                 socklen_t sslen = sizeof(ss);
1007                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1008                                 if (incoming < 0) {
1009                                         switch (errno) {
1010                                         case EAGAIN:
1011                                         case EINTR:
1012                                         case ECONNABORTED:
1013                                                 continue;
1014                                         default:
1015                                                 die_errno("accept returned");
1016                                         }
1017                                 }
1018                                 handle(incoming, &ss.sa, sslen);
1019                         }
1020                 }
1021         }
1022 }
1023
1024 #ifdef NO_POSIX_GOODIES
1025
1026 struct credentials;
1027
1028 static void drop_privileges(struct credentials *cred)
1029 {
1030         /* nothing */
1031 }
1032
1033 static struct credentials *prepare_credentials(const char *user_name,
1034     const char *group_name)
1035 {
1036         die("--user not supported on this platform");
1037 }
1038
1039 #else
1040
1041 struct credentials {
1042         struct passwd *pass;
1043         gid_t gid;
1044 };
1045
1046 static void drop_privileges(struct credentials *cred)
1047 {
1048         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1049             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1050                 die("cannot drop privileges");
1051 }
1052
1053 static struct credentials *prepare_credentials(const char *user_name,
1054     const char *group_name)
1055 {
1056         static struct credentials c;
1057
1058         c.pass = getpwnam(user_name);
1059         if (!c.pass)
1060                 die("user not found - %s", user_name);
1061
1062         if (!group_name)
1063                 c.gid = c.pass->pw_gid;
1064         else {
1065                 struct group *group = getgrnam(group_name);
1066                 if (!group)
1067                         die("group not found - %s", group_name);
1068
1069                 c.gid = group->gr_gid;
1070         }
1071
1072         return &c;
1073 }
1074 #endif
1075
1076 static void store_pid(const char *path)
1077 {
1078         FILE *f = fopen(path, "w");
1079         if (!f)
1080                 die_errno("cannot open pid file '%s'", path);
1081         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1082                 die_errno("failed to write pid file '%s'", path);
1083 }
1084
1085 static int serve(struct string_list *listen_addr, int listen_port,
1086     struct credentials *cred)
1087 {
1088         struct socketlist socklist = { NULL, 0, 0 };
1089
1090         socksetup(listen_addr, listen_port, &socklist);
1091         if (socklist.nr == 0)
1092                 die("unable to allocate any listen sockets on port %u",
1093                     listen_port);
1094
1095         drop_privileges(cred);
1096
1097         loginfo("Ready to rumble");
1098
1099         return service_loop(&socklist);
1100 }
1101
1102 int main(int argc, char **argv)
1103 {
1104         int listen_port = 0;
1105         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1106         int serve_mode = 0, inetd_mode = 0;
1107         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1108         int detach = 0;
1109         struct credentials *cred = NULL;
1110         int i;
1111
1112         git_setup_gettext();
1113
1114         git_extract_argv0_path(argv[0]);
1115
1116         for (i = 1; i < argc; i++) {
1117                 char *arg = argv[i];
1118                 const char *v;
1119
1120                 if (skip_prefix(arg, "--listen=", &v)) {
1121                         string_list_append(&listen_addr, xstrdup_tolower(v));
1122                         continue;
1123                 }
1124                 if (skip_prefix(arg, "--port=", &v)) {
1125                         char *end;
1126                         unsigned long n;
1127                         n = strtoul(v, &end, 0);
1128                         if (*v && !*end) {
1129                                 listen_port = n;
1130                                 continue;
1131                         }
1132                 }
1133                 if (!strcmp(arg, "--serve")) {
1134                         serve_mode = 1;
1135                         continue;
1136                 }
1137                 if (!strcmp(arg, "--inetd")) {
1138                         inetd_mode = 1;
1139                         log_syslog = 1;
1140                         continue;
1141                 }
1142                 if (!strcmp(arg, "--verbose")) {
1143                         verbose = 1;
1144                         continue;
1145                 }
1146                 if (!strcmp(arg, "--syslog")) {
1147                         log_syslog = 1;
1148                         continue;
1149                 }
1150                 if (!strcmp(arg, "--export-all")) {
1151                         export_all_trees = 1;
1152                         continue;
1153                 }
1154                 if (skip_prefix(arg, "--access-hook=", &v)) {
1155                         access_hook = v;
1156                         continue;
1157                 }
1158                 if (skip_prefix(arg, "--timeout=", &v)) {
1159                         timeout = atoi(v);
1160                         continue;
1161                 }
1162                 if (skip_prefix(arg, "--init-timeout=", &v)) {
1163                         init_timeout = atoi(v);
1164                         continue;
1165                 }
1166                 if (skip_prefix(arg, "--max-connections=", &v)) {
1167                         max_connections = atoi(v);
1168                         if (max_connections < 0)
1169                                 max_connections = 0;            /* unlimited */
1170                         continue;
1171                 }
1172                 if (!strcmp(arg, "--strict-paths")) {
1173                         strict_paths = 1;
1174                         continue;
1175                 }
1176                 if (skip_prefix(arg, "--base-path=", &v)) {
1177                         base_path = v;
1178                         continue;
1179                 }
1180                 if (!strcmp(arg, "--base-path-relaxed")) {
1181                         base_path_relaxed = 1;
1182                         continue;
1183                 }
1184                 if (skip_prefix(arg, "--interpolated-path=", &v)) {
1185                         interpolated_path = v;
1186                         continue;
1187                 }
1188                 if (!strcmp(arg, "--reuseaddr")) {
1189                         reuseaddr = 1;
1190                         continue;
1191                 }
1192                 if (!strcmp(arg, "--user-path")) {
1193                         user_path = "";
1194                         continue;
1195                 }
1196                 if (skip_prefix(arg, "--user-path=", &v)) {
1197                         user_path = v;
1198                         continue;
1199                 }
1200                 if (skip_prefix(arg, "--pid-file=", &v)) {
1201                         pid_file = v;
1202                         continue;
1203                 }
1204                 if (!strcmp(arg, "--detach")) {
1205                         detach = 1;
1206                         log_syslog = 1;
1207                         continue;
1208                 }
1209                 if (skip_prefix(arg, "--user=", &v)) {
1210                         user_name = v;
1211                         continue;
1212                 }
1213                 if (skip_prefix(arg, "--group=", &v)) {
1214                         group_name = v;
1215                         continue;
1216                 }
1217                 if (skip_prefix(arg, "--enable=", &v)) {
1218                         enable_service(v, 1);
1219                         continue;
1220                 }
1221                 if (skip_prefix(arg, "--disable=", &v)) {
1222                         enable_service(v, 0);
1223                         continue;
1224                 }
1225                 if (skip_prefix(arg, "--allow-override=", &v)) {
1226                         make_service_overridable(v, 1);
1227                         continue;
1228                 }
1229                 if (skip_prefix(arg, "--forbid-override=", &v)) {
1230                         make_service_overridable(v, 0);
1231                         continue;
1232                 }
1233                 if (!strcmp(arg, "--informative-errors")) {
1234                         informative_errors = 1;
1235                         continue;
1236                 }
1237                 if (!strcmp(arg, "--no-informative-errors")) {
1238                         informative_errors = 0;
1239                         continue;
1240                 }
1241                 if (!strcmp(arg, "--")) {
1242                         ok_paths = &argv[i+1];
1243                         break;
1244                 } else if (arg[0] != '-') {
1245                         ok_paths = &argv[i];
1246                         break;
1247                 }
1248
1249                 usage(daemon_usage);
1250         }
1251
1252         if (log_syslog) {
1253                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1254                 set_die_routine(daemon_die);
1255         } else
1256                 /* avoid splitting a message in the middle */
1257                 setvbuf(stderr, NULL, _IOFBF, 4096);
1258
1259         if (inetd_mode && (detach || group_name || user_name))
1260                 die("--detach, --user and --group are incompatible with --inetd");
1261
1262         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1263                 die("--listen= and --port= are incompatible with --inetd");
1264         else if (listen_port == 0)
1265                 listen_port = DEFAULT_GIT_PORT;
1266
1267         if (group_name && !user_name)
1268                 die("--group supplied without --user");
1269
1270         if (user_name)
1271                 cred = prepare_credentials(user_name, group_name);
1272
1273         if (strict_paths && (!ok_paths || !*ok_paths))
1274                 die("option --strict-paths requires a whitelist");
1275
1276         if (base_path && !is_directory(base_path))
1277                 die("base-path '%s' does not exist or is not a directory",
1278                     base_path);
1279
1280         if (inetd_mode) {
1281                 if (!freopen("/dev/null", "w", stderr))
1282                         die_errno("failed to redirect stderr to /dev/null");
1283         }
1284
1285         if (inetd_mode || serve_mode)
1286                 return execute();
1287
1288         if (detach) {
1289                 if (daemonize())
1290                         die("--detach not supported on this platform");
1291         } else
1292                 sanitize_stdfds();
1293
1294         if (pid_file)
1295                 store_pid(pid_file);
1296
1297         /* prepare argv for serving-processes */
1298         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1299         cld_argv[0] = argv[0];  /* git-daemon */
1300         cld_argv[1] = "--serve";
1301         for (i = 1; i < argc; ++i)
1302                 cld_argv[i+1] = argv[i];
1303         cld_argv[argc+1] = NULL;
1304
1305         return serve(&listen_addr, listen_port, cred);
1306 }