3 #include <sys/socket.h>
7 #include <netinet/in.h>
14 static int log_syslog;
17 static const char daemon_usage[] =
18 "git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all]\n"
19 " [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
20 " [--base-path=path] [directory...]";
22 /* List of acceptable pathname prefixes */
23 static char **ok_paths = NULL;
24 static int strict_paths = 0;
26 /* If this is set, git-daemon-export-ok is not required */
27 static int export_all_trees = 0;
29 /* Take all paths relative to this one if non-NULL */
30 static char *base_path = NULL;
32 /* Timeout, and initial timeout */
33 static unsigned int timeout = 0;
34 static unsigned int init_timeout = 0;
36 static void logreport(int priority, const char *err, va_list params)
38 /* We should do a single write so that it is atomic and output
39 * of several processes do not get intermingled. */
44 /* sizeof(buf) should be big enough for "[pid] \n" */
45 buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
47 maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
48 msglen = vsnprintf(buf + buflen, maxlen, err, params);
51 syslog(priority, "%s", buf);
55 /* maxlen counted our own LF but also counts space given to
56 * vsnprintf for the terminating NUL. We want to make sure that
57 * we have space for our own LF and NUL after the "meat" of the
58 * message, so truncate it at maxlen - 1.
60 if (msglen > maxlen - 1)
63 msglen = 0; /* Protect against weird return values. */
69 write(2, buf, buflen);
72 static void logerror(const char *err, ...)
75 va_start(params, err);
76 logreport(LOG_ERR, err, params);
80 static void loginfo(const char *err, ...)
85 va_start(params, err);
86 logreport(LOG_INFO, err, params);
90 static int avoid_alias(char *p)
95 * This resurrects the belts and suspenders paranoia check by HPA
96 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
97 * does not do getcwd() based path canonicalizations.
99 * sl becomes true immediately after seeing '/' and continues to
100 * be true as long as dots continue after that without intervening
103 if (!p || (*p != '/' && *p != '~'))
113 else if (ch == '/') {
115 /* reject //, /./ and /../ */
120 if (0 < ndot && ndot < 3)
121 /* reject /.$ and /..$ */
130 else if (ch == '/') {
137 static char *path_ok(char *dir)
141 if (avoid_alias(dir)) {
142 logerror("'%s': aliased", dir);
147 static char rpath[PATH_MAX];
148 if (!strict_paths && *dir == '~')
149 ; /* allow user relative paths */
150 else if (*dir != '/') {
151 /* otherwise allow only absolute */
152 logerror("'%s': Non-absolute path denied (base-path active)", dir);
156 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
161 path = enter_repo(dir, strict_paths);
164 logerror("'%s': unable to chdir or not a git archive", dir);
168 if ( ok_paths && *ok_paths ) {
170 int pathlen = strlen(path);
172 /* The validation is done on the paths after enter_repo
173 * appends optional {.git,.git/.git} and friends, but
174 * it does not use getcwd(). So if your /pub is
175 * a symlink to /mnt/pub, you can whitelist /pub and
176 * do not have to say /mnt/pub.
179 for ( pp = ok_paths ; *pp ; pp++ ) {
180 int len = strlen(*pp);
181 if (len <= pathlen &&
182 !memcmp(*pp, path, len) &&
183 (path[len] == '\0' ||
184 (!strict_paths && path[len] == '/')))
189 /* be backwards compatible */
194 logerror("'%s': not in whitelist", path);
195 return NULL; /* Fallthrough. Deny by default */
198 static int upload(char *dir)
200 /* Timeout as string */
201 char timeout_buf[64];
204 loginfo("Request for '%s'", dir);
206 if (!(path = path_ok(dir)))
210 * Security on the cheap.
212 * We want a readable HEAD, usable "objects" directory, and
213 * a "git-daemon-export-ok" flag that says that the other side
214 * is ok with us doing this.
216 * path_ok() uses enter_repo() and does whitelist checking.
217 * We only need to make sure the repository is exported.
220 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
221 logerror("'%s': repository not exported.", path);
227 * We'll ignore SIGTERM from now on, we have a
230 signal(SIGTERM, SIG_IGN);
232 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
234 /* git-upload-pack only ever reads stuff, so this is safe */
235 execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
239 static int execute(void)
241 static char line[1000];
244 alarm(init_timeout ? init_timeout : timeout);
245 len = packet_read_line(0, line, sizeof(line));
248 if (len && line[len-1] == '\n')
251 if (!strncmp("git-upload-pack ", line, 16))
252 return upload(line+16);
254 logerror("Protocol error: '%s'", line);
260 * We count spawned/reaped separately, just to avoid any
261 * races when updating them from signals. The SIGCHLD handler
262 * will only update children_reaped, and the fork logic will
263 * only update children_spawned.
265 * MAX_CHILDREN should be a power-of-two to make the modulus
266 * operation cheap. It should also be at least twice
267 * the maximum number of connections we will ever allow.
269 #define MAX_CHILDREN 128
271 static int max_connections = 25;
273 /* These are updated by the signal handler */
274 static volatile unsigned int children_reaped = 0;
275 static pid_t dead_child[MAX_CHILDREN];
277 /* These are updated by the main loop */
278 static unsigned int children_spawned = 0;
279 static unsigned int children_deleted = 0;
281 static struct child {
284 struct sockaddr_storage address;
285 } live_child[MAX_CHILDREN];
287 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
289 live_child[idx].pid = pid;
290 live_child[idx].addrlen = addrlen;
291 memcpy(&live_child[idx].address, addr, addrlen);
295 * Walk from "deleted" to "spawned", and remove child "pid".
297 * We move everything up by one, since the new "deleted" will
300 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
304 deleted %= MAX_CHILDREN;
305 spawned %= MAX_CHILDREN;
306 if (live_child[deleted].pid == pid) {
307 live_child[deleted].pid = -1;
310 n = live_child[deleted];
313 deleted = (deleted + 1) % MAX_CHILDREN;
314 if (deleted == spawned)
315 die("could not find dead child %d\n", pid);
316 m = live_child[deleted];
317 live_child[deleted] = n;
325 * This gets called if the number of connections grows
326 * past "max_connections".
328 * We _should_ start off by searching for connections
329 * from the same IP, and if there is some address wth
330 * multiple connections, we should kill that first.
332 * As it is, we just "randomly" kill 25% of the connections,
333 * and our pseudo-random generator sucks too. I have no
336 * Really, this is just a place-holder for a _real_ algorithm.
338 static void kill_some_children(int signo, unsigned start, unsigned stop)
340 start %= MAX_CHILDREN;
341 stop %= MAX_CHILDREN;
342 while (start != stop) {
344 kill(live_child[start].pid, signo);
345 start = (start + 1) % MAX_CHILDREN;
349 static void check_max_connections(void)
353 unsigned spawned, reaped, deleted;
355 spawned = children_spawned;
356 reaped = children_reaped;
357 deleted = children_deleted;
359 while (deleted < reaped) {
360 pid_t pid = dead_child[deleted % MAX_CHILDREN];
361 remove_child(pid, deleted, spawned);
364 children_deleted = deleted;
366 active = spawned - deleted;
367 if (active <= max_connections)
370 /* Kill some unstarted connections with SIGTERM */
371 kill_some_children(SIGTERM, deleted, spawned);
372 if (active <= max_connections << 1)
375 /* If the SIGTERM thing isn't helping use SIGKILL */
376 kill_some_children(SIGKILL, deleted, spawned);
381 static void handle(int incoming, struct sockaddr *addr, int addrlen)
384 char addrbuf[256] = "";
394 idx = children_spawned % MAX_CHILDREN;
396 add_child(idx, pid, addr, addrlen);
398 check_max_connections();
406 if (addr->sa_family == AF_INET) {
407 struct sockaddr_in *sin_addr = (void *) addr;
408 inet_ntop(AF_INET, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
409 port = sin_addr->sin_port;
412 } else if (addr->sa_family == AF_INET6) {
413 struct sockaddr_in6 *sin6_addr = (void *) addr;
416 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
417 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
420 port = sin6_addr->sin6_port;
423 loginfo("Connection from %s:%d", addrbuf, port);
428 static void child_handler(int signo)
432 pid_t pid = waitpid(-1, &status, WNOHANG);
435 unsigned reaped = children_reaped;
436 dead_child[reaped % MAX_CHILDREN] = pid;
437 children_reaped = reaped + 1;
438 /* XXX: Custom logging, since we don't wanna getpid() */
441 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
442 dead = " (with error)";
444 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
446 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
456 static int socksetup(int port, int **socklist_p)
458 int socknum = 0, *socklist = NULL;
460 char pbuf[NI_MAXSERV];
462 struct addrinfo hints, *ai0, *ai;
465 sprintf(pbuf, "%d", port);
466 memset(&hints, 0, sizeof(hints));
467 hints.ai_family = AF_UNSPEC;
468 hints.ai_socktype = SOCK_STREAM;
469 hints.ai_protocol = IPPROTO_TCP;
470 hints.ai_flags = AI_PASSIVE;
472 gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
474 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
476 for (ai = ai0; ai; ai = ai->ai_next) {
480 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
483 if (sockfd >= FD_SETSIZE) {
484 error("too large socket descriptor.");
490 if (ai->ai_family == AF_INET6) {
492 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
494 /* Note: error is not fatal */
498 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
500 continue; /* not fatal */
502 if (listen(sockfd, 5) < 0) {
504 continue; /* not fatal */
507 newlist = realloc(socklist, sizeof(int) * (socknum + 1));
509 die("memory allocation failed: %s", strerror(errno));
512 socklist[socknum++] = sockfd;
520 *socklist_p = socklist;
526 static int socksetup(int port, int **socklist_p)
528 struct sockaddr_in sin;
531 sockfd = socket(AF_INET, SOCK_STREAM, 0);
535 memset(&sin, 0, sizeof sin);
536 sin.sin_family = AF_INET;
537 sin.sin_addr.s_addr = htonl(INADDR_ANY);
538 sin.sin_port = htons(port);
540 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
545 if (listen(sockfd, 5) < 0) {
550 *socklist_p = xmalloc(sizeof(int));
551 **socklist_p = sockfd;
557 static int service_loop(int socknum, int *socklist)
562 pfd = xcalloc(socknum, sizeof(struct pollfd));
564 for (i = 0; i < socknum; i++) {
565 pfd[i].fd = socklist[i];
566 pfd[i].events = POLLIN;
569 signal(SIGCHLD, child_handler);
574 if (poll(pfd, socknum, -1) < 0) {
575 if (errno != EINTR) {
576 error("poll failed, resuming: %s",
583 for (i = 0; i < socknum; i++) {
584 if (pfd[i].revents & POLLIN) {
585 struct sockaddr_storage ss;
586 unsigned int sslen = sizeof(ss);
587 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
595 die("accept returned %s", strerror(errno));
598 handle(incoming, (struct sockaddr *)&ss, sslen);
604 static int serve(int port)
606 int socknum, *socklist;
608 socknum = socksetup(port, &socklist);
610 die("unable to allocate any listen sockets on port %u", port);
612 return service_loop(socknum, socklist);
615 int main(int argc, char **argv)
617 int port = DEFAULT_GIT_PORT;
621 for (i = 1; i < argc; i++) {
624 if (!strncmp(arg, "--port=", 7)) {
627 n = strtoul(arg+7, &end, 0);
628 if (arg[7] && !*end) {
633 if (!strcmp(arg, "--inetd")) {
638 if (!strcmp(arg, "--verbose")) {
642 if (!strcmp(arg, "--syslog")) {
646 if (!strcmp(arg, "--export-all")) {
647 export_all_trees = 1;
650 if (!strncmp(arg, "--timeout=", 10)) {
651 timeout = atoi(arg+10);
654 if (!strncmp(arg, "--init-timeout=", 15)) {
655 init_timeout = atoi(arg+15);
658 if (!strcmp(arg, "--strict-paths")) {
662 if (!strncmp(arg, "--base-path=", 12)) {
666 if (!strcmp(arg, "--")) {
667 ok_paths = &argv[i+1];
669 } else if (arg[0] != '-') {
678 openlog("git-daemon", 0, LOG_DAEMON);
680 if (strict_paths && (!ok_paths || !*ok_paths)) {
682 die("git-daemon: option --strict-paths requires a whitelist");
684 logerror("option --strict-paths requires a whitelist");
689 fclose(stderr); //FIXME: workaround