Code

dd3915a07ab63621a55f7c9404659c1039d336cd
[git.git] / daemon.c
1 #include <signal.h>
2 #include <sys/wait.h>
3 #include <sys/socket.h>
4 #include <sys/time.h>
5 #include <sys/poll.h>
6 #include <netdb.h>
7 #include <netinet/in.h>
8 #include <arpa/inet.h>
9 #include <syslog.h>
10 #include <pwd.h>
11 #include <grp.h>
12 #include "pkt-line.h"
13 #include "cache.h"
14 #include "exec_cmd.h"
16 static int log_syslog;
17 static int verbose;
18 static int reuseaddr;
20 static const char daemon_usage[] =
21 "git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all]\n"
22 "           [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
23 "           [--base-path=path] [--user-path | --user-path=path]\n"
24 "           [--reuseaddr] [--detach] [--pid-file=file]\n"
25 "           [--user=user [[--group=group]] [directory...]";
27 /* List of acceptable pathname prefixes */
28 static char **ok_paths;
29 static int strict_paths;
31 /* If this is set, git-daemon-export-ok is not required */
32 static int export_all_trees;
34 /* Take all paths relative to this one if non-NULL */
35 static char *base_path;
37 /* If defined, ~user notation is allowed and the string is inserted
38  * after ~user/.  E.g. a request to git://host/~alice/frotz would
39  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
40  */
41 static const char *user_path;
43 /* Timeout, and initial timeout */
44 static unsigned int timeout;
45 static unsigned int init_timeout;
47 static void logreport(int priority, const char *err, va_list params)
48 {
49         /* We should do a single write so that it is atomic and output
50          * of several processes do not get intermingled. */
51         char buf[1024];
52         int buflen;
53         int maxlen, msglen;
55         /* sizeof(buf) should be big enough for "[pid] \n" */
56         buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
58         maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
59         msglen = vsnprintf(buf + buflen, maxlen, err, params);
61         if (log_syslog) {
62                 syslog(priority, "%s", buf);
63                 return;
64         }
66         /* maxlen counted our own LF but also counts space given to
67          * vsnprintf for the terminating NUL.  We want to make sure that
68          * we have space for our own LF and NUL after the "meat" of the
69          * message, so truncate it at maxlen - 1.
70          */
71         if (msglen > maxlen - 1)
72                 msglen = maxlen - 1;
73         else if (msglen < 0)
74                 msglen = 0; /* Protect against weird return values. */
75         buflen += msglen;
77         buf[buflen++] = '\n';
78         buf[buflen] = '\0';
80         write(2, buf, buflen);
81 }
83 static void logerror(const char *err, ...)
84 {
85         va_list params;
86         va_start(params, err);
87         logreport(LOG_ERR, err, params);
88         va_end(params);
89 }
91 static void loginfo(const char *err, ...)
92 {
93         va_list params;
94         if (!verbose)
95                 return;
96         va_start(params, err);
97         logreport(LOG_INFO, err, params);
98         va_end(params);
99 }
101 static void NORETURN daemon_die(const char *err, va_list params)
103         logreport(LOG_ERR, err, params);
104         exit(1);
107 static int avoid_alias(char *p)
109         int sl, ndot;
111         /* 
112          * This resurrects the belts and suspenders paranoia check by HPA
113          * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
114          * does not do getcwd() based path canonicalizations.
115          *
116          * sl becomes true immediately after seeing '/' and continues to
117          * be true as long as dots continue after that without intervening
118          * non-dot character.
119          */
120         if (!p || (*p != '/' && *p != '~'))
121                 return -1;
122         sl = 1; ndot = 0;
123         p++;
125         while (1) {
126                 char ch = *p++;
127                 if (sl) {
128                         if (ch == '.')
129                                 ndot++;
130                         else if (ch == '/') {
131                                 if (ndot < 3)
132                                         /* reject //, /./ and /../ */
133                                         return -1;
134                                 ndot = 0;
135                         }
136                         else if (ch == 0) {
137                                 if (0 < ndot && ndot < 3)
138                                         /* reject /.$ and /..$ */
139                                         return -1;
140                                 return 0;
141                         }
142                         else
143                                 sl = ndot = 0;
144                 }
145                 else if (ch == 0)
146                         return 0;
147                 else if (ch == '/') {
148                         sl = 1;
149                         ndot = 0;
150                 }
151         }
154 static char *path_ok(char *dir)
156         static char rpath[PATH_MAX];
157         char *path;
159         if (avoid_alias(dir)) {
160                 logerror("'%s': aliased", dir);
161                 return NULL;
162         }
164         if (*dir == '~') {
165                 if (!user_path) {
166                         logerror("'%s': User-path not allowed", dir);
167                         return NULL;
168                 }
169                 if (*user_path) {
170                         /* Got either "~alice" or "~alice/foo";
171                          * rewrite them to "~alice/%s" or
172                          * "~alice/%s/foo".
173                          */
174                         int namlen, restlen = strlen(dir);
175                         char *slash = strchr(dir, '/');
176                         if (!slash)
177                                 slash = dir + restlen;
178                         namlen = slash - dir;
179                         restlen -= namlen;
180                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
181                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
182                                  namlen, dir, user_path, restlen, slash);
183                         dir = rpath;
184                 }
185         }
186         else if (base_path) {
187                 if (*dir != '/') {
188                         /* Allow only absolute */
189                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
190                         return NULL;
191                 }
192                 else {
193                         snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
194                         dir = rpath;
195                 }
196         }
198         path = enter_repo(dir, strict_paths);
200         if (!path) {
201                 logerror("'%s': unable to chdir or not a git archive", dir);
202                 return NULL;
203         }
205         if ( ok_paths && *ok_paths ) {
206                 char **pp;
207                 int pathlen = strlen(path);
209                 /* The validation is done on the paths after enter_repo
210                  * appends optional {.git,.git/.git} and friends, but 
211                  * it does not use getcwd().  So if your /pub is
212                  * a symlink to /mnt/pub, you can whitelist /pub and
213                  * do not have to say /mnt/pub.
214                  * Do not say /pub/.
215                  */
216                 for ( pp = ok_paths ; *pp ; pp++ ) {
217                         int len = strlen(*pp);
218                         if (len <= pathlen &&
219                             !memcmp(*pp, path, len) &&
220                             (path[len] == '\0' ||
221                              (!strict_paths && path[len] == '/')))
222                                 return path;
223                 }
224         }
225         else {
226                 /* be backwards compatible */
227                 if (!strict_paths)
228                         return path;
229         }
231         logerror("'%s': not in whitelist", path);
232         return NULL;            /* Fallthrough. Deny by default */
235 static int upload(char *dir)
237         /* Timeout as string */
238         char timeout_buf[64];
239         const char *path;
241         loginfo("Request for '%s'", dir);
243         if (!(path = path_ok(dir)))
244                 return -1;
246         /*
247          * Security on the cheap.
248          *
249          * We want a readable HEAD, usable "objects" directory, and
250          * a "git-daemon-export-ok" flag that says that the other side
251          * is ok with us doing this.
252          *
253          * path_ok() uses enter_repo() and does whitelist checking.
254          * We only need to make sure the repository is exported.
255          */
257         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
258                 logerror("'%s': repository not exported.", path);
259                 errno = EACCES;
260                 return -1;
261         }
263         /*
264          * We'll ignore SIGTERM from now on, we have a
265          * good client.
266          */
267         signal(SIGTERM, SIG_IGN);
269         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
271         /* git-upload-pack only ever reads stuff, so this is safe */
272         execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
273         return -1;
276 static int execute(struct sockaddr *addr)
278         static char line[1000];
279         int pktlen, len;
281         if (addr) {
282                 char addrbuf[256] = "";
283                 int port = -1;
285                 if (addr->sa_family == AF_INET) {
286                         struct sockaddr_in *sin_addr = (void *) addr;
287                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
288                         port = sin_addr->sin_port;
289 #ifndef NO_IPV6
290                 } else if (addr && addr->sa_family == AF_INET6) {
291                         struct sockaddr_in6 *sin6_addr = (void *) addr;
293                         char *buf = addrbuf;
294                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
295                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
296                         strcat(buf, "]");
298                         port = sin6_addr->sin6_port;
299 #endif
300                 }
301                 loginfo("Connection from %s:%d", addrbuf, port);
302         }
304         alarm(init_timeout ? init_timeout : timeout);
305         pktlen = packet_read_line(0, line, sizeof(line));
306         alarm(0);
308         len = strlen(line);
309         if (pktlen != len)
310                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
311                         (int) pktlen - len,
312                         (int) pktlen - len, line + len + 1);
313         if (len && line[len-1] == '\n')
314                 line[--len] = 0;
316         if (!strncmp("git-upload-pack ", line, 16))
317                 return upload(line+16);
319         logerror("Protocol error: '%s'", line);
320         return -1;
324 /*
325  * We count spawned/reaped separately, just to avoid any
326  * races when updating them from signals. The SIGCHLD handler
327  * will only update children_reaped, and the fork logic will
328  * only update children_spawned.
329  *
330  * MAX_CHILDREN should be a power-of-two to make the modulus
331  * operation cheap. It should also be at least twice
332  * the maximum number of connections we will ever allow.
333  */
334 #define MAX_CHILDREN 128
336 static int max_connections = 25;
338 /* These are updated by the signal handler */
339 static volatile unsigned int children_reaped;
340 static pid_t dead_child[MAX_CHILDREN];
342 /* These are updated by the main loop */
343 static unsigned int children_spawned;
344 static unsigned int children_deleted;
346 static struct child {
347         pid_t pid;
348         int addrlen;
349         struct sockaddr_storage address;
350 } live_child[MAX_CHILDREN];
352 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
354         live_child[idx].pid = pid;
355         live_child[idx].addrlen = addrlen;
356         memcpy(&live_child[idx].address, addr, addrlen);
359 /*
360  * Walk from "deleted" to "spawned", and remove child "pid".
361  *
362  * We move everything up by one, since the new "deleted" will
363  * be one higher.
364  */
365 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
367         struct child n;
369         deleted %= MAX_CHILDREN;
370         spawned %= MAX_CHILDREN;
371         if (live_child[deleted].pid == pid) {
372                 live_child[deleted].pid = -1;
373                 return;
374         }
375         n = live_child[deleted];
376         for (;;) {
377                 struct child m;
378                 deleted = (deleted + 1) % MAX_CHILDREN;
379                 if (deleted == spawned)
380                         die("could not find dead child %d\n", pid);
381                 m = live_child[deleted];
382                 live_child[deleted] = n;
383                 if (m.pid == pid)
384                         return;
385                 n = m;
386         }
389 /*
390  * This gets called if the number of connections grows
391  * past "max_connections".
392  *
393  * We _should_ start off by searching for connections
394  * from the same IP, and if there is some address wth
395  * multiple connections, we should kill that first.
396  *
397  * As it is, we just "randomly" kill 25% of the connections,
398  * and our pseudo-random generator sucks too. I have no
399  * shame.
400  *
401  * Really, this is just a place-holder for a _real_ algorithm.
402  */
403 static void kill_some_children(int signo, unsigned start, unsigned stop)
405         start %= MAX_CHILDREN;
406         stop %= MAX_CHILDREN;
407         while (start != stop) {
408                 if (!(start & 3))
409                         kill(live_child[start].pid, signo);
410                 start = (start + 1) % MAX_CHILDREN;
411         }
414 static void check_max_connections(void)
416         for (;;) {
417                 int active;
418                 unsigned spawned, reaped, deleted;
420                 spawned = children_spawned;
421                 reaped = children_reaped;
422                 deleted = children_deleted;
424                 while (deleted < reaped) {
425                         pid_t pid = dead_child[deleted % MAX_CHILDREN];
426                         remove_child(pid, deleted, spawned);
427                         deleted++;
428                 }
429                 children_deleted = deleted;
431                 active = spawned - deleted;
432                 if (active <= max_connections)
433                         break;
435                 /* Kill some unstarted connections with SIGTERM */
436                 kill_some_children(SIGTERM, deleted, spawned);
437                 if (active <= max_connections << 1)
438                         break;
440                 /* If the SIGTERM thing isn't helping use SIGKILL */
441                 kill_some_children(SIGKILL, deleted, spawned);
442                 sleep(1);
443         }
446 static void handle(int incoming, struct sockaddr *addr, int addrlen)
448         pid_t pid = fork();
450         if (pid) {
451                 unsigned idx;
453                 close(incoming);
454                 if (pid < 0)
455                         return;
457                 idx = children_spawned % MAX_CHILDREN;
458                 children_spawned++;
459                 add_child(idx, pid, addr, addrlen);
461                 check_max_connections();
462                 return;
463         }
465         dup2(incoming, 0);
466         dup2(incoming, 1);
467         close(incoming);
469         exit(execute(addr));
472 static void child_handler(int signo)
474         for (;;) {
475                 int status;
476                 pid_t pid = waitpid(-1, &status, WNOHANG);
478                 if (pid > 0) {
479                         unsigned reaped = children_reaped;
480                         dead_child[reaped % MAX_CHILDREN] = pid;
481                         children_reaped = reaped + 1;
482                         /* XXX: Custom logging, since we don't wanna getpid() */
483                         if (verbose) {
484                                 const char *dead = "";
485                                 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
486                                         dead = " (with error)";
487                                 if (log_syslog)
488                                         syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
489                                 else
490                                         fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
491                         }
492                         continue;
493                 }
494                 break;
495         }
498 static int set_reuse_addr(int sockfd)
500         int on = 1;
502         if (!reuseaddr)
503                 return 0;
504         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
505                           &on, sizeof(on));
508 #ifndef NO_IPV6
510 static int socksetup(int port, int **socklist_p)
512         int socknum = 0, *socklist = NULL;
513         int maxfd = -1;
514         char pbuf[NI_MAXSERV];
516         struct addrinfo hints, *ai0, *ai;
517         int gai;
519         sprintf(pbuf, "%d", port);
520         memset(&hints, 0, sizeof(hints));
521         hints.ai_family = AF_UNSPEC;
522         hints.ai_socktype = SOCK_STREAM;
523         hints.ai_protocol = IPPROTO_TCP;
524         hints.ai_flags = AI_PASSIVE;
526         gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
527         if (gai)
528                 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
530         for (ai = ai0; ai; ai = ai->ai_next) {
531                 int sockfd;
532                 int *newlist;
534                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
535                 if (sockfd < 0)
536                         continue;
537                 if (sockfd >= FD_SETSIZE) {
538                         error("too large socket descriptor.");
539                         close(sockfd);
540                         continue;
541                 }
543 #ifdef IPV6_V6ONLY
544                 if (ai->ai_family == AF_INET6) {
545                         int on = 1;
546                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
547                                    &on, sizeof(on));
548                         /* Note: error is not fatal */
549                 }
550 #endif
552                 if (set_reuse_addr(sockfd)) {
553                         close(sockfd);
554                         continue;
555                 }
557                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
558                         close(sockfd);
559                         continue;       /* not fatal */
560                 }
561                 if (listen(sockfd, 5) < 0) {
562                         close(sockfd);
563                         continue;       /* not fatal */
564                 }
566                 newlist = realloc(socklist, sizeof(int) * (socknum + 1));
567                 if (!newlist)
568                         die("memory allocation failed: %s", strerror(errno));
570                 socklist = newlist;
571                 socklist[socknum++] = sockfd;
573                 if (maxfd < sockfd)
574                         maxfd = sockfd;
575         }
577         freeaddrinfo(ai0);
579         *socklist_p = socklist;
580         return socknum;
583 #else /* NO_IPV6 */
585 static int socksetup(int port, int **socklist_p)
587         struct sockaddr_in sin;
588         int sockfd;
590         sockfd = socket(AF_INET, SOCK_STREAM, 0);
591         if (sockfd < 0)
592                 return 0;
594         memset(&sin, 0, sizeof sin);
595         sin.sin_family = AF_INET;
596         sin.sin_addr.s_addr = htonl(INADDR_ANY);
597         sin.sin_port = htons(port);
599         if (set_reuse_addr(sockfd)) {
600                 close(sockfd);
601                 return 0;
602         }
604         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
605                 close(sockfd);
606                 return 0;
607         }
609         if (listen(sockfd, 5) < 0) {
610                 close(sockfd);
611                 return 0;
612         }
614         *socklist_p = xmalloc(sizeof(int));
615         **socklist_p = sockfd;
616         return 1;
619 #endif
621 static int service_loop(int socknum, int *socklist)
623         struct pollfd *pfd;
624         int i;
626         pfd = xcalloc(socknum, sizeof(struct pollfd));
628         for (i = 0; i < socknum; i++) {
629                 pfd[i].fd = socklist[i];
630                 pfd[i].events = POLLIN;
631         }
633         signal(SIGCHLD, child_handler);
635         for (;;) {
636                 int i;
638                 if (poll(pfd, socknum, -1) < 0) {
639                         if (errno != EINTR) {
640                                 error("poll failed, resuming: %s",
641                                       strerror(errno));
642                                 sleep(1);
643                         }
644                         continue;
645                 }
647                 for (i = 0; i < socknum; i++) {
648                         if (pfd[i].revents & POLLIN) {
649                                 struct sockaddr_storage ss;
650                                 unsigned int sslen = sizeof(ss);
651                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
652                                 if (incoming < 0) {
653                                         switch (errno) {
654                                         case EAGAIN:
655                                         case EINTR:
656                                         case ECONNABORTED:
657                                                 continue;
658                                         default:
659                                                 die("accept returned %s", strerror(errno));
660                                         }
661                                 }
662                                 handle(incoming, (struct sockaddr *)&ss, sslen);
663                         }
664                 }
665         }
668 /* if any standard file descriptor is missing open it to /dev/null */
669 static void sanitize_stdfds(void)
671         int fd = open("/dev/null", O_RDWR, 0);
672         while (fd != -1 && fd < 2)
673                 fd = dup(fd);
674         if (fd == -1)
675                 die("open /dev/null or dup failed: %s", strerror(errno));
676         if (fd > 2)
677                 close(fd);
680 static void daemonize(void)
682         switch (fork()) {
683                 case 0:
684                         break;
685                 case -1:
686                         die("fork failed: %s", strerror(errno));
687                 default:
688                         exit(0);
689         }
690         if (setsid() == -1)
691                 die("setsid failed: %s", strerror(errno));
692         close(0);
693         close(1);
694         close(2);
695         sanitize_stdfds();
698 static void store_pid(const char *path)
700         FILE *f = fopen(path, "w");
701         if (!f)
702                 die("cannot open pid file %s: %s", path, strerror(errno));
703         fprintf(f, "%d\n", getpid());
704         fclose(f);
707 static int serve(int port, struct passwd *pass, gid_t gid)
709         int socknum, *socklist;
711         socknum = socksetup(port, &socklist);
712         if (socknum == 0)
713                 die("unable to allocate any listen sockets on port %u", port);
715         if (pass && gid &&
716             (initgroups(pass->pw_name, gid) || setgid (gid) ||
717              setuid(pass->pw_uid)))
718                 die("cannot drop privileges");
720         return service_loop(socknum, socklist);
723 int main(int argc, char **argv)
725         int port = DEFAULT_GIT_PORT;
726         int inetd_mode = 0;
727         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
728         int detach = 0;
729         struct passwd *pass = NULL;
730         struct group *group;
731         gid_t gid = 0;
732         int i;
734         /* Without this we cannot rely on waitpid() to tell
735          * what happened to our children.
736          */
737         signal(SIGCHLD, SIG_DFL);
739         for (i = 1; i < argc; i++) {
740                 char *arg = argv[i];
742                 if (!strncmp(arg, "--port=", 7)) {
743                         char *end;
744                         unsigned long n;
745                         n = strtoul(arg+7, &end, 0);
746                         if (arg[7] && !*end) {
747                                 port = n;
748                                 continue;
749                         }
750                 }
751                 if (!strcmp(arg, "--inetd")) {
752                         inetd_mode = 1;
753                         log_syslog = 1;
754                         continue;
755                 }
756                 if (!strcmp(arg, "--verbose")) {
757                         verbose = 1;
758                         continue;
759                 }
760                 if (!strcmp(arg, "--syslog")) {
761                         log_syslog = 1;
762                         continue;
763                 }
764                 if (!strcmp(arg, "--export-all")) {
765                         export_all_trees = 1;
766                         continue;
767                 }
768                 if (!strncmp(arg, "--timeout=", 10)) {
769                         timeout = atoi(arg+10);
770                         continue;
771                 }
772                 if (!strncmp(arg, "--init-timeout=", 15)) {
773                         init_timeout = atoi(arg+15);
774                         continue;
775                 }
776                 if (!strcmp(arg, "--strict-paths")) {
777                         strict_paths = 1;
778                         continue;
779                 }
780                 if (!strncmp(arg, "--base-path=", 12)) {
781                         base_path = arg+12;
782                         continue;
783                 }
784                 if (!strcmp(arg, "--reuseaddr")) {
785                         reuseaddr = 1;
786                         continue;
787                 }
788                 if (!strcmp(arg, "--user-path")) {
789                         user_path = "";
790                         continue;
791                 }
792                 if (!strncmp(arg, "--user-path=", 12)) {
793                         user_path = arg + 12;
794                         continue;
795                 }
796                 if (!strncmp(arg, "--pid-file=", 11)) {
797                         pid_file = arg + 11;
798                         continue;
799                 }
800                 if (!strcmp(arg, "--detach")) {
801                         detach = 1;
802                         log_syslog = 1;
803                         continue;
804                 }
805                 if (!strncmp(arg, "--user=", 7)) {
806                         user_name = arg + 7;
807                         continue;
808                 }
809                 if (!strncmp(arg, "--group=", 8)) {
810                         group_name = arg + 8;
811                         continue;
812                 }
813                 if (!strcmp(arg, "--")) {
814                         ok_paths = &argv[i+1];
815                         break;
816                 } else if (arg[0] != '-') {
817                         ok_paths = &argv[i];
818                         break;
819                 }
821                 usage(daemon_usage);
822         }
824         if (inetd_mode && (group_name || user_name))
825                 die("--user and --group are incompatible with --inetd");
827         if (group_name && !user_name)
828                 die("--group supplied without --user");
830         if (user_name) {
831                 pass = getpwnam(user_name);
832                 if (!pass)
833                         die("user not found - %s", user_name);
835                 if (!group_name)
836                         gid = pass->pw_gid;
837                 else {
838                         group = getgrnam(group_name);
839                         if (!group)
840                                 die("group not found - %s", group_name);
842                         gid = group->gr_gid;
843                 }
844         }
846         if (log_syslog) {
847                 openlog("git-daemon", 0, LOG_DAEMON);
848                 set_die_routine(daemon_die);
849         }
851         if (strict_paths && (!ok_paths || !*ok_paths))
852                 die("option --strict-paths requires a whitelist");
854         if (inetd_mode) {
855                 struct sockaddr_storage ss;
856                 struct sockaddr *peer = (struct sockaddr *)&ss;
857                 socklen_t slen = sizeof(ss);
859                 freopen("/dev/null", "w", stderr);
861                 if (getpeername(0, peer, &slen))
862                         peer = NULL;
864                 return execute(peer);
865         }
867         if (detach)
868                 daemonize();
869         else
870                 sanitize_stdfds();
872         if (pid_file)
873                 store_pid(pid_file);
875         return serve(port, pass, gid);