GIT 1.4.0
[alt-git.git] / daemon.c
blob2f03f99d2d9f2ed9a23932e5104456f69b721116
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 "pkt-line.h"
11 #include "cache.h"
12 #include "exec_cmd.h"
14 static int log_syslog;
15 static int verbose;
16 static int reuseaddr;
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 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. */
48 char buf[1024];
49 int buflen;
50 int maxlen, msglen;
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);
58 if (log_syslog) {
59 syslog(priority, "%s", buf);
60 return;
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)
69 msglen = maxlen - 1;
70 else if (msglen < 0)
71 msglen = 0; /* Protect against weird return values. */
72 buflen += msglen;
74 buf[buflen++] = '\n';
75 buf[buflen] = '\0';
77 write(2, buf, buflen);
80 static void logerror(const char *err, ...)
82 va_list params;
83 va_start(params, err);
84 logreport(LOG_ERR, err, params);
85 va_end(params);
88 static void loginfo(const char *err, ...)
90 va_list params;
91 if (!verbose)
92 return;
93 va_start(params, err);
94 logreport(LOG_INFO, err, params);
95 va_end(params);
98 static int avoid_alias(char *p)
100 int sl, ndot;
103 * This resurrects the belts and suspenders paranoia check by HPA
104 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
105 * does not do getcwd() based path canonicalizations.
107 * sl becomes true immediately after seeing '/' and continues to
108 * be true as long as dots continue after that without intervening
109 * non-dot character.
111 if (!p || (*p != '/' && *p != '~'))
112 return -1;
113 sl = 1; ndot = 0;
114 p++;
116 while (1) {
117 char ch = *p++;
118 if (sl) {
119 if (ch == '.')
120 ndot++;
121 else if (ch == '/') {
122 if (ndot < 3)
123 /* reject //, /./ and /../ */
124 return -1;
125 ndot = 0;
127 else if (ch == 0) {
128 if (0 < ndot && ndot < 3)
129 /* reject /.$ and /..$ */
130 return -1;
131 return 0;
133 else
134 sl = ndot = 0;
136 else if (ch == 0)
137 return 0;
138 else if (ch == '/') {
139 sl = 1;
140 ndot = 0;
145 static char *path_ok(char *dir)
147 static char rpath[PATH_MAX];
148 char *path;
150 if (avoid_alias(dir)) {
151 logerror("'%s': aliased", dir);
152 return NULL;
155 if (*dir == '~') {
156 if (!user_path) {
157 logerror("'%s': User-path not allowed", dir);
158 return NULL;
160 if (*user_path) {
161 /* Got either "~alice" or "~alice/foo";
162 * rewrite them to "~alice/%s" or
163 * "~alice/%s/foo".
165 int namlen, restlen = strlen(dir);
166 char *slash = strchr(dir, '/');
167 if (!slash)
168 slash = dir + restlen;
169 namlen = slash - dir;
170 restlen -= namlen;
171 loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
172 snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
173 namlen, dir, user_path, restlen, slash);
174 dir = rpath;
177 else if (base_path) {
178 if (*dir != '/') {
179 /* Allow only absolute */
180 logerror("'%s': Non-absolute path denied (base-path active)", dir);
181 return NULL;
183 else {
184 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
185 dir = rpath;
189 path = enter_repo(dir, strict_paths);
191 if (!path) {
192 logerror("'%s': unable to chdir or not a git archive", dir);
193 return NULL;
196 if ( ok_paths && *ok_paths ) {
197 char **pp;
198 int pathlen = strlen(path);
200 /* The validation is done on the paths after enter_repo
201 * appends optional {.git,.git/.git} and friends, but
202 * it does not use getcwd(). So if your /pub is
203 * a symlink to /mnt/pub, you can whitelist /pub and
204 * do not have to say /mnt/pub.
205 * Do not say /pub/.
207 for ( pp = ok_paths ; *pp ; pp++ ) {
208 int len = strlen(*pp);
209 if (len <= pathlen &&
210 !memcmp(*pp, path, len) &&
211 (path[len] == '\0' ||
212 (!strict_paths && path[len] == '/')))
213 return path;
216 else {
217 /* be backwards compatible */
218 if (!strict_paths)
219 return path;
222 logerror("'%s': not in whitelist", path);
223 return NULL; /* Fallthrough. Deny by default */
226 static int upload(char *dir)
228 /* Timeout as string */
229 char timeout_buf[64];
230 const char *path;
232 loginfo("Request for '%s'", dir);
234 if (!(path = path_ok(dir)))
235 return -1;
238 * Security on the cheap.
240 * We want a readable HEAD, usable "objects" directory, and
241 * a "git-daemon-export-ok" flag that says that the other side
242 * is ok with us doing this.
244 * path_ok() uses enter_repo() and does whitelist checking.
245 * We only need to make sure the repository is exported.
248 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
249 logerror("'%s': repository not exported.", path);
250 errno = EACCES;
251 return -1;
255 * We'll ignore SIGTERM from now on, we have a
256 * good client.
258 signal(SIGTERM, SIG_IGN);
260 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
262 /* git-upload-pack only ever reads stuff, so this is safe */
263 execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
264 return -1;
267 static int execute(void)
269 static char line[1000];
270 int pktlen, len;
272 alarm(init_timeout ? init_timeout : timeout);
273 pktlen = packet_read_line(0, line, sizeof(line));
274 alarm(0);
276 len = strlen(line);
277 if (pktlen != len)
278 loginfo("Extended attributes (%d bytes) exist <%.*s>",
279 (int) pktlen - len,
280 (int) pktlen - len, line + len + 1);
281 if (len && line[len-1] == '\n')
282 line[--len] = 0;
284 if (!strncmp("git-upload-pack ", line, 16))
285 return upload(line+16);
287 logerror("Protocol error: '%s'", line);
288 return -1;
293 * We count spawned/reaped separately, just to avoid any
294 * races when updating them from signals. The SIGCHLD handler
295 * will only update children_reaped, and the fork logic will
296 * only update children_spawned.
298 * MAX_CHILDREN should be a power-of-two to make the modulus
299 * operation cheap. It should also be at least twice
300 * the maximum number of connections we will ever allow.
302 #define MAX_CHILDREN 128
304 static int max_connections = 25;
306 /* These are updated by the signal handler */
307 static volatile unsigned int children_reaped = 0;
308 static pid_t dead_child[MAX_CHILDREN];
310 /* These are updated by the main loop */
311 static unsigned int children_spawned = 0;
312 static unsigned int children_deleted = 0;
314 static struct child {
315 pid_t pid;
316 int addrlen;
317 struct sockaddr_storage address;
318 } live_child[MAX_CHILDREN];
320 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
322 live_child[idx].pid = pid;
323 live_child[idx].addrlen = addrlen;
324 memcpy(&live_child[idx].address, addr, addrlen);
328 * Walk from "deleted" to "spawned", and remove child "pid".
330 * We move everything up by one, since the new "deleted" will
331 * be one higher.
333 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
335 struct child n;
337 deleted %= MAX_CHILDREN;
338 spawned %= MAX_CHILDREN;
339 if (live_child[deleted].pid == pid) {
340 live_child[deleted].pid = -1;
341 return;
343 n = live_child[deleted];
344 for (;;) {
345 struct child m;
346 deleted = (deleted + 1) % MAX_CHILDREN;
347 if (deleted == spawned)
348 die("could not find dead child %d\n", pid);
349 m = live_child[deleted];
350 live_child[deleted] = n;
351 if (m.pid == pid)
352 return;
353 n = m;
358 * This gets called if the number of connections grows
359 * past "max_connections".
361 * We _should_ start off by searching for connections
362 * from the same IP, and if there is some address wth
363 * multiple connections, we should kill that first.
365 * As it is, we just "randomly" kill 25% of the connections,
366 * and our pseudo-random generator sucks too. I have no
367 * shame.
369 * Really, this is just a place-holder for a _real_ algorithm.
371 static void kill_some_children(int signo, unsigned start, unsigned stop)
373 start %= MAX_CHILDREN;
374 stop %= MAX_CHILDREN;
375 while (start != stop) {
376 if (!(start & 3))
377 kill(live_child[start].pid, signo);
378 start = (start + 1) % MAX_CHILDREN;
382 static void check_max_connections(void)
384 for (;;) {
385 int active;
386 unsigned spawned, reaped, deleted;
388 spawned = children_spawned;
389 reaped = children_reaped;
390 deleted = children_deleted;
392 while (deleted < reaped) {
393 pid_t pid = dead_child[deleted % MAX_CHILDREN];
394 remove_child(pid, deleted, spawned);
395 deleted++;
397 children_deleted = deleted;
399 active = spawned - deleted;
400 if (active <= max_connections)
401 break;
403 /* Kill some unstarted connections with SIGTERM */
404 kill_some_children(SIGTERM, deleted, spawned);
405 if (active <= max_connections << 1)
406 break;
408 /* If the SIGTERM thing isn't helping use SIGKILL */
409 kill_some_children(SIGKILL, deleted, spawned);
410 sleep(1);
414 static void handle(int incoming, struct sockaddr *addr, int addrlen)
416 pid_t pid = fork();
417 char addrbuf[256] = "";
418 int port = -1;
420 if (pid) {
421 unsigned idx;
423 close(incoming);
424 if (pid < 0)
425 return;
427 idx = children_spawned % MAX_CHILDREN;
428 children_spawned++;
429 add_child(idx, pid, addr, addrlen);
431 check_max_connections();
432 return;
435 dup2(incoming, 0);
436 dup2(incoming, 1);
437 close(incoming);
439 if (addr->sa_family == AF_INET) {
440 struct sockaddr_in *sin_addr = (void *) addr;
441 inet_ntop(AF_INET, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
442 port = sin_addr->sin_port;
444 #ifndef NO_IPV6
445 } else if (addr->sa_family == AF_INET6) {
446 struct sockaddr_in6 *sin6_addr = (void *) addr;
448 char *buf = addrbuf;
449 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
450 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
451 strcat(buf, "]");
453 port = sin6_addr->sin6_port;
454 #endif
456 loginfo("Connection from %s:%d", addrbuf, port);
458 exit(execute());
461 static void child_handler(int signo)
463 for (;;) {
464 int status;
465 pid_t pid = waitpid(-1, &status, WNOHANG);
467 if (pid > 0) {
468 unsigned reaped = children_reaped;
469 dead_child[reaped % MAX_CHILDREN] = pid;
470 children_reaped = reaped + 1;
471 /* XXX: Custom logging, since we don't wanna getpid() */
472 if (verbose) {
473 char *dead = "";
474 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
475 dead = " (with error)";
476 if (log_syslog)
477 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
478 else
479 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
481 continue;
483 break;
487 static int set_reuse_addr(int sockfd)
489 int on = 1;
491 if (!reuseaddr)
492 return 0;
493 return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
494 &on, sizeof(on));
497 #ifndef NO_IPV6
499 static int socksetup(int port, int **socklist_p)
501 int socknum = 0, *socklist = NULL;
502 int maxfd = -1;
503 char pbuf[NI_MAXSERV];
505 struct addrinfo hints, *ai0, *ai;
506 int gai;
508 sprintf(pbuf, "%d", port);
509 memset(&hints, 0, sizeof(hints));
510 hints.ai_family = AF_UNSPEC;
511 hints.ai_socktype = SOCK_STREAM;
512 hints.ai_protocol = IPPROTO_TCP;
513 hints.ai_flags = AI_PASSIVE;
515 gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
516 if (gai)
517 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
519 for (ai = ai0; ai; ai = ai->ai_next) {
520 int sockfd;
521 int *newlist;
523 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
524 if (sockfd < 0)
525 continue;
526 if (sockfd >= FD_SETSIZE) {
527 error("too large socket descriptor.");
528 close(sockfd);
529 continue;
532 #ifdef IPV6_V6ONLY
533 if (ai->ai_family == AF_INET6) {
534 int on = 1;
535 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
536 &on, sizeof(on));
537 /* Note: error is not fatal */
539 #endif
541 if (set_reuse_addr(sockfd)) {
542 close(sockfd);
543 continue;
546 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
547 close(sockfd);
548 continue; /* not fatal */
550 if (listen(sockfd, 5) < 0) {
551 close(sockfd);
552 continue; /* not fatal */
555 newlist = realloc(socklist, sizeof(int) * (socknum + 1));
556 if (!newlist)
557 die("memory allocation failed: %s", strerror(errno));
559 socklist = newlist;
560 socklist[socknum++] = sockfd;
562 if (maxfd < sockfd)
563 maxfd = sockfd;
566 freeaddrinfo(ai0);
568 *socklist_p = socklist;
569 return socknum;
572 #else /* NO_IPV6 */
574 static int socksetup(int port, int **socklist_p)
576 struct sockaddr_in sin;
577 int sockfd;
579 sockfd = socket(AF_INET, SOCK_STREAM, 0);
580 if (sockfd < 0)
581 return 0;
583 memset(&sin, 0, sizeof sin);
584 sin.sin_family = AF_INET;
585 sin.sin_addr.s_addr = htonl(INADDR_ANY);
586 sin.sin_port = htons(port);
588 if (set_reuse_addr(sockfd)) {
589 close(sockfd);
590 return 0;
593 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
594 close(sockfd);
595 return 0;
598 if (listen(sockfd, 5) < 0) {
599 close(sockfd);
600 return 0;
603 *socklist_p = xmalloc(sizeof(int));
604 **socklist_p = sockfd;
605 return 1;
608 #endif
610 static int service_loop(int socknum, int *socklist)
612 struct pollfd *pfd;
613 int i;
615 pfd = xcalloc(socknum, sizeof(struct pollfd));
617 for (i = 0; i < socknum; i++) {
618 pfd[i].fd = socklist[i];
619 pfd[i].events = POLLIN;
622 signal(SIGCHLD, child_handler);
624 for (;;) {
625 int i;
627 if (poll(pfd, socknum, -1) < 0) {
628 if (errno != EINTR) {
629 error("poll failed, resuming: %s",
630 strerror(errno));
631 sleep(1);
633 continue;
636 for (i = 0; i < socknum; i++) {
637 if (pfd[i].revents & POLLIN) {
638 struct sockaddr_storage ss;
639 unsigned int sslen = sizeof(ss);
640 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
641 if (incoming < 0) {
642 switch (errno) {
643 case EAGAIN:
644 case EINTR:
645 case ECONNABORTED:
646 continue;
647 default:
648 die("accept returned %s", strerror(errno));
651 handle(incoming, (struct sockaddr *)&ss, sslen);
657 static int serve(int port)
659 int socknum, *socklist;
661 socknum = socksetup(port, &socklist);
662 if (socknum == 0)
663 die("unable to allocate any listen sockets on port %u", port);
665 return service_loop(socknum, socklist);
668 int main(int argc, char **argv)
670 int port = DEFAULT_GIT_PORT;
671 int inetd_mode = 0;
672 int i;
674 for (i = 1; i < argc; i++) {
675 char *arg = argv[i];
677 if (!strncmp(arg, "--port=", 7)) {
678 char *end;
679 unsigned long n;
680 n = strtoul(arg+7, &end, 0);
681 if (arg[7] && !*end) {
682 port = n;
683 continue;
686 if (!strcmp(arg, "--inetd")) {
687 inetd_mode = 1;
688 log_syslog = 1;
689 continue;
691 if (!strcmp(arg, "--verbose")) {
692 verbose = 1;
693 continue;
695 if (!strcmp(arg, "--syslog")) {
696 log_syslog = 1;
697 continue;
699 if (!strcmp(arg, "--export-all")) {
700 export_all_trees = 1;
701 continue;
703 if (!strncmp(arg, "--timeout=", 10)) {
704 timeout = atoi(arg+10);
705 continue;
707 if (!strncmp(arg, "--init-timeout=", 15)) {
708 init_timeout = atoi(arg+15);
709 continue;
711 if (!strcmp(arg, "--strict-paths")) {
712 strict_paths = 1;
713 continue;
715 if (!strncmp(arg, "--base-path=", 12)) {
716 base_path = arg+12;
717 continue;
719 if (!strcmp(arg, "--reuseaddr")) {
720 reuseaddr = 1;
721 continue;
723 if (!strcmp(arg, "--user-path")) {
724 user_path = "";
725 continue;
727 if (!strncmp(arg, "--user-path=", 12)) {
728 user_path = arg + 12;
729 continue;
731 if (!strcmp(arg, "--")) {
732 ok_paths = &argv[i+1];
733 break;
734 } else if (arg[0] != '-') {
735 ok_paths = &argv[i];
736 break;
739 usage(daemon_usage);
742 if (log_syslog)
743 openlog("git-daemon", 0, LOG_DAEMON);
745 if (strict_paths && (!ok_paths || !*ok_paths)) {
746 if (!inetd_mode)
747 die("git-daemon: option --strict-paths requires a whitelist");
749 logerror("option --strict-paths requires a whitelist");
750 exit (1);
753 if (inetd_mode) {
754 fclose(stderr); //FIXME: workaround
755 return execute();
758 return serve(port);