Merge branch 'fixes'
[git/jnareb-git.git] / daemon.c
blob65e62d7bb16943ce47d426d817bc313889d68dfa
1 #include "cache.h"
2 #include "pkt-line.h"
3 #include <signal.h>
4 #include <sys/wait.h>
5 #include <sys/socket.h>
6 #include <sys/time.h>
7 #include <netdb.h>
8 #include <netinet/in.h>
9 #include <arpa/inet.h>
10 #include <syslog.h>
12 static int log_syslog;
13 static int verbose;
15 static const char daemon_usage[] = "git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all] [directory...]";
17 /* List of acceptable pathname prefixes */
18 static char **ok_paths = NULL;
20 /* If this is set, git-daemon-export-ok is not required */
21 static int export_all_trees = 0;
24 static void logreport(int priority, const char *err, va_list params)
26 /* We should do a single write so that it is atomic and output
27 * of several processes do not get intermingled. */
28 char buf[1024];
29 int buflen;
30 int maxlen, msglen;
32 /* sizeof(buf) should be big enough for "[pid] \n" */
33 buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
35 maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
36 msglen = vsnprintf(buf + buflen, maxlen, err, params);
38 if (log_syslog) {
39 syslog(priority, "%s", buf);
40 return;
43 /* maxlen counted our own LF but also counts space given to
44 * vsnprintf for the terminating NUL. We want to make sure that
45 * we have space for our own LF and NUL after the "meat" of the
46 * message, so truncate it at maxlen - 1.
48 if (msglen > maxlen - 1)
49 msglen = maxlen - 1;
50 else if (msglen < 0)
51 msglen = 0; /* Protect against weird return values. */
52 buflen += msglen;
54 buf[buflen++] = '\n';
55 buf[buflen] = '\0';
57 write(2, buf, buflen);
60 static void logerror(const char *err, ...)
62 va_list params;
63 va_start(params, err);
64 logreport(LOG_ERR, err, params);
65 va_end(params);
68 static void loginfo(const char *err, ...)
70 va_list params;
71 if (!verbose)
72 return;
73 va_start(params, err);
74 logreport(LOG_INFO, err, params);
75 va_end(params);
78 static int path_ok(const char *dir)
80 const char *p = dir;
81 char **pp;
82 int sl = 1, ndot = 0;
84 for (;;) {
85 if ( *p == '.' ) {
86 ndot++;
87 } else if ( *p == '/' || *p == '\0' ) {
88 if ( sl && ndot > 0 && ndot < 3 )
89 return 0; /* . or .. in path */
90 sl = 1;
91 if ( *p == '\0' )
92 break; /* End of string and all is good */
93 } else {
94 sl = ndot = 0;
96 p++;
99 if ( ok_paths && *ok_paths ) {
100 int ok = 0;
101 int dirlen = strlen(dir); /* read_packet_line can return embedded \0 */
103 for ( pp = ok_paths ; *pp ; pp++ ) {
104 int len = strlen(*pp);
105 if ( len <= dirlen &&
106 !strncmp(*pp, dir, len) &&
107 (dir[len] == '/' || dir[len] == '\0') ) {
108 ok = 1;
109 break;
113 if ( !ok )
114 return 0; /* Path not in whitelist */
117 return 1; /* Path acceptable */
120 static int upload(char *dir, int dirlen)
122 loginfo("Request for '%s'", dir);
124 if (!path_ok(dir)) {
125 logerror("Forbidden directory: %s\n", dir);
126 return -1;
129 if (chdir(dir) < 0) {
130 logerror("Cannot chdir('%s'): %s", dir, strerror(errno));
131 return -1;
134 chdir(".git");
137 * Security on the cheap.
139 * We want a readable HEAD, usable "objects" directory, and
140 * a "git-daemon-export-ok" flag that says that the other side
141 * is ok with us doing this.
143 if ((!export_all_trees && access("git-daemon-export-ok", F_OK)) ||
144 access("objects/00", X_OK) ||
145 access("HEAD", R_OK)) {
146 logerror("Not a valid git-daemon-enabled repository: '%s'", dir);
147 return -1;
151 * We'll ignore SIGTERM from now on, we have a
152 * good client.
154 signal(SIGTERM, SIG_IGN);
156 /* git-upload-pack only ever reads stuff, so this is safe */
157 execlp("git-upload-pack", "git-upload-pack", ".", NULL);
158 return -1;
161 static int execute(void)
163 static char line[1000];
164 int len;
166 len = packet_read_line(0, line, sizeof(line));
168 if (len && line[len-1] == '\n')
169 line[--len] = 0;
171 if (!strncmp("git-upload-pack /", line, 17))
172 return upload(line + 16, len - 16);
174 logerror("Protocol error: '%s'", line);
175 return -1;
180 * We count spawned/reaped separately, just to avoid any
181 * races when updating them from signals. The SIGCHLD handler
182 * will only update children_reaped, and the fork logic will
183 * only update children_spawned.
185 * MAX_CHILDREN should be a power-of-two to make the modulus
186 * operation cheap. It should also be at least twice
187 * the maximum number of connections we will ever allow.
189 #define MAX_CHILDREN 128
191 static int max_connections = 25;
193 /* These are updated by the signal handler */
194 static volatile unsigned int children_reaped = 0;
195 static pid_t dead_child[MAX_CHILDREN];
197 /* These are updated by the main loop */
198 static unsigned int children_spawned = 0;
199 static unsigned int children_deleted = 0;
201 static struct child {
202 pid_t pid;
203 int addrlen;
204 struct sockaddr_storage address;
205 } live_child[MAX_CHILDREN];
207 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
209 live_child[idx].pid = pid;
210 live_child[idx].addrlen = addrlen;
211 memcpy(&live_child[idx].address, addr, addrlen);
215 * Walk from "deleted" to "spawned", and remove child "pid".
217 * We move everything up by one, since the new "deleted" will
218 * be one higher.
220 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
222 struct child n;
224 deleted %= MAX_CHILDREN;
225 spawned %= MAX_CHILDREN;
226 if (live_child[deleted].pid == pid) {
227 live_child[deleted].pid = -1;
228 return;
230 n = live_child[deleted];
231 for (;;) {
232 struct child m;
233 deleted = (deleted + 1) % MAX_CHILDREN;
234 if (deleted == spawned)
235 die("could not find dead child %d\n", pid);
236 m = live_child[deleted];
237 live_child[deleted] = n;
238 if (m.pid == pid)
239 return;
240 n = m;
245 * This gets called if the number of connections grows
246 * past "max_connections".
248 * We _should_ start off by searching for connections
249 * from the same IP, and if there is some address wth
250 * multiple connections, we should kill that first.
252 * As it is, we just "randomly" kill 25% of the connections,
253 * and our pseudo-random generator sucks too. I have no
254 * shame.
256 * Really, this is just a place-holder for a _real_ algorithm.
258 static void kill_some_children(int signo, unsigned start, unsigned stop)
260 start %= MAX_CHILDREN;
261 stop %= MAX_CHILDREN;
262 while (start != stop) {
263 if (!(start & 3))
264 kill(live_child[start].pid, signo);
265 start = (start + 1) % MAX_CHILDREN;
269 static void check_max_connections(void)
271 for (;;) {
272 int active;
273 unsigned spawned, reaped, deleted;
275 spawned = children_spawned;
276 reaped = children_reaped;
277 deleted = children_deleted;
279 while (deleted < reaped) {
280 pid_t pid = dead_child[deleted % MAX_CHILDREN];
281 remove_child(pid, deleted, spawned);
282 deleted++;
284 children_deleted = deleted;
286 active = spawned - deleted;
287 if (active <= max_connections)
288 break;
290 /* Kill some unstarted connections with SIGTERM */
291 kill_some_children(SIGTERM, deleted, spawned);
292 if (active <= max_connections << 1)
293 break;
295 /* If the SIGTERM thing isn't helping use SIGKILL */
296 kill_some_children(SIGKILL, deleted, spawned);
297 sleep(1);
301 static void handle(int incoming, struct sockaddr *addr, int addrlen)
303 pid_t pid = fork();
304 char addrbuf[256] = "";
305 int port = -1;
307 if (pid) {
308 unsigned idx;
310 close(incoming);
311 if (pid < 0)
312 return;
314 idx = children_spawned % MAX_CHILDREN;
315 children_spawned++;
316 add_child(idx, pid, addr, addrlen);
318 check_max_connections();
319 return;
322 dup2(incoming, 0);
323 dup2(incoming, 1);
324 close(incoming);
326 if (addr->sa_family == AF_INET) {
327 struct sockaddr_in *sin_addr = (void *) addr;
328 inet_ntop(AF_INET, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
329 port = sin_addr->sin_port;
331 } else if (addr->sa_family == AF_INET6) {
332 struct sockaddr_in6 *sin6_addr = (void *) addr;
334 char *buf = addrbuf;
335 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
336 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
337 strcat(buf, "]");
339 port = sin6_addr->sin6_port;
341 loginfo("Connection from %s:%d", addrbuf, port);
343 exit(execute());
346 static void child_handler(int signo)
348 for (;;) {
349 int status;
350 pid_t pid = waitpid(-1, &status, WNOHANG);
352 if (pid > 0) {
353 unsigned reaped = children_reaped;
354 dead_child[reaped % MAX_CHILDREN] = pid;
355 children_reaped = reaped + 1;
356 /* XXX: Custom logging, since we don't wanna getpid() */
357 if (verbose) {
358 char *dead = "";
359 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
360 dead = " (with error)";
361 if (log_syslog)
362 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
363 else
364 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
366 continue;
368 break;
372 static int serve(int port)
374 struct addrinfo hints, *ai0, *ai;
375 int gai;
376 int socknum = 0, *socklist = NULL;
377 int maxfd = -1;
378 fd_set fds_init, fds;
379 char pbuf[NI_MAXSERV];
381 signal(SIGCHLD, child_handler);
383 sprintf(pbuf, "%d", port);
384 memset(&hints, 0, sizeof(hints));
385 hints.ai_family = AF_UNSPEC;
386 hints.ai_socktype = SOCK_STREAM;
387 hints.ai_protocol = IPPROTO_TCP;
388 hints.ai_flags = AI_PASSIVE;
390 gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
391 if (gai)
392 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
394 FD_ZERO(&fds_init);
396 for (ai = ai0; ai; ai = ai->ai_next) {
397 int sockfd;
398 int *newlist;
400 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
401 if (sockfd < 0)
402 continue;
403 if (sockfd >= FD_SETSIZE) {
404 error("too large socket descriptor.");
405 close(sockfd);
406 continue;
409 #ifdef IPV6_V6ONLY
410 if (ai->ai_family == AF_INET6) {
411 int on = 1;
412 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
413 &on, sizeof(on));
414 /* Note: error is not fatal */
416 #endif
418 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
419 close(sockfd);
420 continue; /* not fatal */
422 if (listen(sockfd, 5) < 0) {
423 close(sockfd);
424 continue; /* not fatal */
427 newlist = realloc(socklist, sizeof(int) * (socknum + 1));
428 if (!newlist)
429 die("memory allocation failed: %s", strerror(errno));
431 socklist = newlist;
432 socklist[socknum++] = sockfd;
434 FD_SET(sockfd, &fds_init);
435 if (maxfd < sockfd)
436 maxfd = sockfd;
439 freeaddrinfo(ai0);
441 if (socknum == 0)
442 die("unable to allocate any listen sockets on port %u", port);
444 for (;;) {
445 int i;
446 fds = fds_init;
448 if (select(maxfd + 1, &fds, NULL, NULL, NULL) < 0) {
449 if (errno != EINTR) {
450 error("select failed, resuming: %s",
451 strerror(errno));
452 sleep(1);
454 continue;
457 for (i = 0; i < socknum; i++) {
458 int sockfd = socklist[i];
460 if (FD_ISSET(sockfd, &fds)) {
461 struct sockaddr_storage ss;
462 int sslen = sizeof(ss);
463 int incoming = accept(sockfd, (struct sockaddr *)&ss, &sslen);
464 if (incoming < 0) {
465 switch (errno) {
466 case EAGAIN:
467 case EINTR:
468 case ECONNABORTED:
469 continue;
470 default:
471 die("accept returned %s", strerror(errno));
474 handle(incoming, (struct sockaddr *)&ss, sslen);
480 int main(int argc, char **argv)
482 int port = DEFAULT_GIT_PORT;
483 int inetd_mode = 0;
484 int i;
486 for (i = 1; i < argc; i++) {
487 char *arg = argv[i];
489 if (!strncmp(arg, "--port=", 7)) {
490 char *end;
491 unsigned long n;
492 n = strtoul(arg+7, &end, 0);
493 if (arg[7] && !*end) {
494 port = n;
495 continue;
498 if (!strcmp(arg, "--inetd")) {
499 inetd_mode = 1;
500 continue;
502 if (!strcmp(arg, "--verbose")) {
503 verbose = 1;
504 continue;
506 if (!strcmp(arg, "--syslog")) {
507 log_syslog = 1;
508 openlog("git-daemon", 0, LOG_DAEMON);
509 continue;
511 if (!strcmp(arg, "--export-all")) {
512 export_all_trees = 1;
513 continue;
515 if (!strcmp(arg, "--")) {
516 ok_paths = &argv[i+1];
517 break;
518 } else if (arg[0] != '-') {
519 ok_paths = &argv[i];
520 break;
523 usage(daemon_usage);
526 if (inetd_mode) {
527 fclose(stderr); //FIXME: workaround
528 return execute();
531 return serve(port);