3 #include <sys/socket.h>
7 #include <netinet/in.h>
14 static int log_syslog;
18 static const char daemon_usage[] =
19 "git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all]\n"
20 " [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
21 " [--base-path=path] [--user-path | --user-path=path]\n"
22 " [--reuseaddr] [directory...]";
24 /* List of acceptable pathname prefixes */
25 static char **ok_paths = NULL;
26 static int strict_paths = 0;
28 /* If this is set, git-daemon-export-ok is not required */
29 static int export_all_trees = 0;
31 /* Take all paths relative to this one if non-NULL */
32 static char *base_path = NULL;
34 /* If defined, ~user notation is allowed and the string is inserted
35 * after ~user/. E.g. a request to git://host/~alice/frotz would
36 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
38 static const char *user_path = NULL;
40 /* Timeout, and initial timeout */
41 static unsigned int timeout = 0;
42 static unsigned int init_timeout = 0;
44 static void logreport(int priority, const char *err, va_list params)
46 /* We should do a single write so that it is atomic and output
47 * of several processes do not get intermingled. */
52 /* sizeof(buf) should be big enough for "[pid] \n" */
53 buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
55 maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
56 msglen = vsnprintf(buf + buflen, maxlen, err, params);
59 syslog(priority, "%s", buf);
63 /* maxlen counted our own LF but also counts space given to
64 * vsnprintf for the terminating NUL. We want to make sure that
65 * we have space for our own LF and NUL after the "meat" of the
66 * message, so truncate it at maxlen - 1.
68 if (msglen > maxlen - 1)
71 msglen = 0; /* Protect against weird return values. */
77 write(2, buf, buflen);
80 static void logerror(const char *err, ...)
83 va_start(params, err);
84 logreport(LOG_ERR, err, params);
88 static void loginfo(const char *err, ...)
93 va_start(params, err);
94 logreport(LOG_INFO, err, params);
98 static void NORETURN daemon_die(const char *err, va_list params)
100 logreport(LOG_ERR, err, params);
104 static int avoid_alias(char *p)
109 * This resurrects the belts and suspenders paranoia check by HPA
110 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
111 * does not do getcwd() based path canonicalizations.
113 * sl becomes true immediately after seeing '/' and continues to
114 * be true as long as dots continue after that without intervening
117 if (!p || (*p != '/' && *p != '~'))
127 else if (ch == '/') {
129 /* reject //, /./ and /../ */
134 if (0 < ndot && ndot < 3)
135 /* reject /.$ and /..$ */
144 else if (ch == '/') {
151 static char *path_ok(char *dir)
153 static char rpath[PATH_MAX];
156 if (avoid_alias(dir)) {
157 logerror("'%s': aliased", dir);
163 logerror("'%s': User-path not allowed", dir);
167 /* Got either "~alice" or "~alice/foo";
168 * rewrite them to "~alice/%s" or
171 int namlen, restlen = strlen(dir);
172 char *slash = strchr(dir, '/');
174 slash = dir + restlen;
175 namlen = slash - dir;
177 loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
178 snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
179 namlen, dir, user_path, restlen, slash);
183 else if (base_path) {
185 /* Allow only absolute */
186 logerror("'%s': Non-absolute path denied (base-path active)", dir);
190 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
195 path = enter_repo(dir, strict_paths);
198 logerror("'%s': unable to chdir or not a git archive", dir);
202 if ( ok_paths && *ok_paths ) {
204 int pathlen = strlen(path);
206 /* The validation is done on the paths after enter_repo
207 * appends optional {.git,.git/.git} and friends, but
208 * it does not use getcwd(). So if your /pub is
209 * a symlink to /mnt/pub, you can whitelist /pub and
210 * do not have to say /mnt/pub.
213 for ( pp = ok_paths ; *pp ; pp++ ) {
214 int len = strlen(*pp);
215 if (len <= pathlen &&
216 !memcmp(*pp, path, len) &&
217 (path[len] == '\0' ||
218 (!strict_paths && path[len] == '/')))
223 /* be backwards compatible */
228 logerror("'%s': not in whitelist", path);
229 return NULL; /* Fallthrough. Deny by default */
232 static int upload(char *dir)
234 /* Timeout as string */
235 char timeout_buf[64];
238 loginfo("Request for '%s'", dir);
240 if (!(path = path_ok(dir)))
244 * Security on the cheap.
246 * We want a readable HEAD, usable "objects" directory, and
247 * a "git-daemon-export-ok" flag that says that the other side
248 * is ok with us doing this.
250 * path_ok() uses enter_repo() and does whitelist checking.
251 * We only need to make sure the repository is exported.
254 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
255 logerror("'%s': repository not exported.", path);
261 * We'll ignore SIGTERM from now on, we have a
264 signal(SIGTERM, SIG_IGN);
266 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
268 /* git-upload-pack only ever reads stuff, so this is safe */
269 execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
273 static int execute(struct sockaddr *addr)
275 static char line[1000];
279 char addrbuf[256] = "";
282 if (addr->sa_family == AF_INET) {
283 struct sockaddr_in *sin_addr = (void *) addr;
284 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
285 port = sin_addr->sin_port;
287 } else if (addr && addr->sa_family == AF_INET6) {
288 struct sockaddr_in6 *sin6_addr = (void *) addr;
291 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
292 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
295 port = sin6_addr->sin6_port;
298 loginfo("Connection from %s:%d", addrbuf, port);
301 alarm(init_timeout ? init_timeout : timeout);
302 pktlen = packet_read_line(0, line, sizeof(line));
307 loginfo("Extended attributes (%d bytes) exist <%.*s>",
309 (int) pktlen - len, line + len + 1);
310 if (len && line[len-1] == '\n')
313 if (!strncmp("git-upload-pack ", line, 16))
314 return upload(line+16);
316 logerror("Protocol error: '%s'", line);
322 * We count spawned/reaped separately, just to avoid any
323 * races when updating them from signals. The SIGCHLD handler
324 * will only update children_reaped, and the fork logic will
325 * only update children_spawned.
327 * MAX_CHILDREN should be a power-of-two to make the modulus
328 * operation cheap. It should also be at least twice
329 * the maximum number of connections we will ever allow.
331 #define MAX_CHILDREN 128
333 static int max_connections = 25;
335 /* These are updated by the signal handler */
336 static volatile unsigned int children_reaped = 0;
337 static pid_t dead_child[MAX_CHILDREN];
339 /* These are updated by the main loop */
340 static unsigned int children_spawned = 0;
341 static unsigned int children_deleted = 0;
343 static struct child {
346 struct sockaddr_storage address;
347 } live_child[MAX_CHILDREN];
349 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
351 live_child[idx].pid = pid;
352 live_child[idx].addrlen = addrlen;
353 memcpy(&live_child[idx].address, addr, addrlen);
357 * Walk from "deleted" to "spawned", and remove child "pid".
359 * We move everything up by one, since the new "deleted" will
362 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
366 deleted %= MAX_CHILDREN;
367 spawned %= MAX_CHILDREN;
368 if (live_child[deleted].pid == pid) {
369 live_child[deleted].pid = -1;
372 n = live_child[deleted];
375 deleted = (deleted + 1) % MAX_CHILDREN;
376 if (deleted == spawned)
377 die("could not find dead child %d\n", pid);
378 m = live_child[deleted];
379 live_child[deleted] = n;
387 * This gets called if the number of connections grows
388 * past "max_connections".
390 * We _should_ start off by searching for connections
391 * from the same IP, and if there is some address wth
392 * multiple connections, we should kill that first.
394 * As it is, we just "randomly" kill 25% of the connections,
395 * and our pseudo-random generator sucks too. I have no
398 * Really, this is just a place-holder for a _real_ algorithm.
400 static void kill_some_children(int signo, unsigned start, unsigned stop)
402 start %= MAX_CHILDREN;
403 stop %= MAX_CHILDREN;
404 while (start != stop) {
406 kill(live_child[start].pid, signo);
407 start = (start + 1) % MAX_CHILDREN;
411 static void check_max_connections(void)
415 unsigned spawned, reaped, deleted;
417 spawned = children_spawned;
418 reaped = children_reaped;
419 deleted = children_deleted;
421 while (deleted < reaped) {
422 pid_t pid = dead_child[deleted % MAX_CHILDREN];
423 remove_child(pid, deleted, spawned);
426 children_deleted = deleted;
428 active = spawned - deleted;
429 if (active <= max_connections)
432 /* Kill some unstarted connections with SIGTERM */
433 kill_some_children(SIGTERM, deleted, spawned);
434 if (active <= max_connections << 1)
437 /* If the SIGTERM thing isn't helping use SIGKILL */
438 kill_some_children(SIGKILL, deleted, spawned);
443 static void handle(int incoming, struct sockaddr *addr, int addrlen)
454 idx = children_spawned % MAX_CHILDREN;
456 add_child(idx, pid, addr, addrlen);
458 check_max_connections();
469 static void child_handler(int signo)
473 pid_t pid = waitpid(-1, &status, WNOHANG);
476 unsigned reaped = children_reaped;
477 dead_child[reaped % MAX_CHILDREN] = pid;
478 children_reaped = reaped + 1;
479 /* XXX: Custom logging, since we don't wanna getpid() */
481 const char *dead = "";
482 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
483 dead = " (with error)";
485 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
487 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
495 static int set_reuse_addr(int sockfd)
501 return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
507 static int socksetup(int port, int **socklist_p)
509 int socknum = 0, *socklist = NULL;
511 char pbuf[NI_MAXSERV];
513 struct addrinfo hints, *ai0, *ai;
516 sprintf(pbuf, "%d", port);
517 memset(&hints, 0, sizeof(hints));
518 hints.ai_family = AF_UNSPEC;
519 hints.ai_socktype = SOCK_STREAM;
520 hints.ai_protocol = IPPROTO_TCP;
521 hints.ai_flags = AI_PASSIVE;
523 gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
525 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
527 for (ai = ai0; ai; ai = ai->ai_next) {
531 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
534 if (sockfd >= FD_SETSIZE) {
535 error("too large socket descriptor.");
541 if (ai->ai_family == AF_INET6) {
543 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
545 /* Note: error is not fatal */
549 if (set_reuse_addr(sockfd)) {
554 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
556 continue; /* not fatal */
558 if (listen(sockfd, 5) < 0) {
560 continue; /* not fatal */
563 newlist = realloc(socklist, sizeof(int) * (socknum + 1));
565 die("memory allocation failed: %s", strerror(errno));
568 socklist[socknum++] = sockfd;
576 *socklist_p = socklist;
582 static int socksetup(int port, int **socklist_p)
584 struct sockaddr_in sin;
587 sockfd = socket(AF_INET, SOCK_STREAM, 0);
591 memset(&sin, 0, sizeof sin);
592 sin.sin_family = AF_INET;
593 sin.sin_addr.s_addr = htonl(INADDR_ANY);
594 sin.sin_port = htons(port);
596 if (set_reuse_addr(sockfd)) {
601 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
606 if (listen(sockfd, 5) < 0) {
611 *socklist_p = xmalloc(sizeof(int));
612 **socklist_p = sockfd;
618 static int service_loop(int socknum, int *socklist)
623 pfd = xcalloc(socknum, sizeof(struct pollfd));
625 for (i = 0; i < socknum; i++) {
626 pfd[i].fd = socklist[i];
627 pfd[i].events = POLLIN;
630 signal(SIGCHLD, child_handler);
635 if (poll(pfd, socknum, -1) < 0) {
636 if (errno != EINTR) {
637 error("poll failed, resuming: %s",
644 for (i = 0; i < socknum; i++) {
645 if (pfd[i].revents & POLLIN) {
646 struct sockaddr_storage ss;
647 unsigned int sslen = sizeof(ss);
648 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
656 die("accept returned %s", strerror(errno));
659 handle(incoming, (struct sockaddr *)&ss, sslen);
665 /* if any standard file descriptor is missing open it to /dev/null */
666 static void sanitize_stdfds(void)
668 int fd = open("/dev/null", O_RDWR, 0);
669 while (fd != -1 && fd < 2)
672 die("open /dev/null or dup failed: %s", strerror(errno));
677 static void daemonize(void)
683 die("fork failed: %s", strerror(errno));
688 die("setsid failed: %s", strerror(errno));
695 static void store_pid(const char *path)
697 FILE *f = fopen(path, "w");
699 die("cannot open pid file %s: %s", path, strerror(errno));
700 fprintf(f, "%d\n", getpid());
704 static int serve(int port)
706 int socknum, *socklist;
708 socknum = socksetup(port, &socklist);
710 die("unable to allocate any listen sockets on port %u", port);
712 return service_loop(socknum, socklist);
715 int main(int argc, char **argv)
717 int port = DEFAULT_GIT_PORT;
719 const char *pid_file = NULL;
723 /* Without this we cannot rely on waitpid() to tell
724 * what happened to our children.
726 signal(SIGCHLD, SIG_DFL);
728 for (i = 1; i < argc; i++) {
731 if (!strncmp(arg, "--port=", 7)) {
734 n = strtoul(arg+7, &end, 0);
735 if (arg[7] && !*end) {
740 if (!strcmp(arg, "--inetd")) {
745 if (!strcmp(arg, "--verbose")) {
749 if (!strcmp(arg, "--syslog")) {
753 if (!strcmp(arg, "--export-all")) {
754 export_all_trees = 1;
757 if (!strncmp(arg, "--timeout=", 10)) {
758 timeout = atoi(arg+10);
761 if (!strncmp(arg, "--init-timeout=", 15)) {
762 init_timeout = atoi(arg+15);
765 if (!strcmp(arg, "--strict-paths")) {
769 if (!strncmp(arg, "--base-path=", 12)) {
773 if (!strcmp(arg, "--reuseaddr")) {
777 if (!strcmp(arg, "--user-path")) {
781 if (!strncmp(arg, "--user-path=", 12)) {
782 user_path = arg + 12;
785 if (!strncmp(arg, "--pid-file=", 11)) {
789 if (!strcmp(arg, "--detach")) {
794 if (!strcmp(arg, "--")) {
795 ok_paths = &argv[i+1];
797 } else if (arg[0] != '-') {
806 openlog("git-daemon", 0, LOG_DAEMON);
807 set_die_routine(daemon_die);
810 if (strict_paths && (!ok_paths || !*ok_paths))
811 die("option --strict-paths requires a whitelist");
814 struct sockaddr_storage ss;
815 struct sockaddr *peer = (struct sockaddr *)&ss;
816 socklen_t slen = sizeof(ss);
818 freopen("/dev/null", "w", stderr);
820 if (getpeername(0, peer, &slen))
823 return execute(peer);