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checkout -f: do not leave untracked working tree files.
[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 "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.
37  */
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)
45 {
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;
61         }
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.
67          */
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);
78 }
80 static void logerror(const char *err, ...)
81 {
82         va_list params;
83         va_start(params, err);
84         logreport(LOG_ERR, err, params);
85         va_end(params);
86 }
88 static void loginfo(const char *err, ...)
89 {
90         va_list params;
91         if (!verbose)
92                 return;
93         va_start(params, err);
94         logreport(LOG_INFO, err, params);
95         va_end(params);
96 }
98 static int avoid_alias(char *p)
99 {
100         int sl, ndot;
102         /* 
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.
106          *
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.
110          */
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;
126                         }
127                         else if (ch == 0) {
128                                 if (0 < ndot && ndot < 3)
129                                         /* reject /.$ and /..$ */
130                                         return -1;
131                                 return 0;
132                         }
133                         else
134                                 sl = ndot = 0;
135                 }
136                 else if (ch == 0)
137                         return 0;
138                 else if (ch == '/') {
139                         sl = 1;
140                         ndot = 0;
141                 }
142         }
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;
153         }
155         if (*dir == '~') {
156                 if (!user_path) {
157                         logerror("'%s': User-path not allowed", dir);
158                         return NULL;
159                 }
160                 if (*user_path) {
161                         /* Got either "~alice" or "~alice/foo";
162                          * rewrite them to "~alice/%s" or
163                          * "~alice/%s/foo".
164                          */
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;
175                 }
176         }
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;
182                 }
183                 else {
184                         snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
185                         dir = rpath;
186                 }
187         }
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;
194         }
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/.
206                  */
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;
214                 }
215         }
216         else {
217                 /* be backwards compatible */
218                 if (!strict_paths)
219                         return path;
220         }
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;
237         /*
238          * Security on the cheap.
239          *
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.
243          *
244          * path_ok() uses enter_repo() and does whitelist checking.
245          * We only need to make sure the repository is exported.
246          */
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;
252         }
254         /*
255          * We'll ignore SIGTERM from now on, we have a
256          * good client.
257          */
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(struct sockaddr *addr)
269         static char line[1000];
270         int pktlen, len;
272         if (addr) {
273                 char addrbuf[256] = "";
274                 int port = -1;
276                 if (addr->sa_family == AF_INET) {
277                         struct sockaddr_in *sin_addr = (void *) addr;
278                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
279                         port = sin_addr->sin_port;
280 #ifndef NO_IPV6
281                 } else if (addr && addr->sa_family == AF_INET6) {
282                         struct sockaddr_in6 *sin6_addr = (void *) addr;
284                         char *buf = addrbuf;
285                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
286                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
287                         strcat(buf, "]");
289                         port = sin6_addr->sin6_port;
290 #endif
291                 }
292                 loginfo("Connection from %s:%d", addrbuf, port);
293         }
295         alarm(init_timeout ? init_timeout : timeout);
296         pktlen = packet_read_line(0, line, sizeof(line));
297         alarm(0);
299         len = strlen(line);
300         if (pktlen != len)
301                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
302                         (int) pktlen - len,
303                         (int) pktlen - len, line + len + 1);
304         if (len && line[len-1] == '\n')
305                 line[--len] = 0;
307         if (!strncmp("git-upload-pack ", line, 16))
308                 return upload(line+16);
310         logerror("Protocol error: '%s'", line);
311         return -1;
315 /*
316  * We count spawned/reaped separately, just to avoid any
317  * races when updating them from signals. The SIGCHLD handler
318  * will only update children_reaped, and the fork logic will
319  * only update children_spawned.
320  *
321  * MAX_CHILDREN should be a power-of-two to make the modulus
322  * operation cheap. It should also be at least twice
323  * the maximum number of connections we will ever allow.
324  */
325 #define MAX_CHILDREN 128
327 static int max_connections = 25;
329 /* These are updated by the signal handler */
330 static volatile unsigned int children_reaped = 0;
331 static pid_t dead_child[MAX_CHILDREN];
333 /* These are updated by the main loop */
334 static unsigned int children_spawned = 0;
335 static unsigned int children_deleted = 0;
337 static struct child {
338         pid_t pid;
339         int addrlen;
340         struct sockaddr_storage address;
341 } live_child[MAX_CHILDREN];
343 static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
345         live_child[idx].pid = pid;
346         live_child[idx].addrlen = addrlen;
347         memcpy(&live_child[idx].address, addr, addrlen);
350 /*
351  * Walk from "deleted" to "spawned", and remove child "pid".
352  *
353  * We move everything up by one, since the new "deleted" will
354  * be one higher.
355  */
356 static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
358         struct child n;
360         deleted %= MAX_CHILDREN;
361         spawned %= MAX_CHILDREN;
362         if (live_child[deleted].pid == pid) {
363                 live_child[deleted].pid = -1;
364                 return;
365         }
366         n = live_child[deleted];
367         for (;;) {
368                 struct child m;
369                 deleted = (deleted + 1) % MAX_CHILDREN;
370                 if (deleted == spawned)
371                         die("could not find dead child %d\n", pid);
372                 m = live_child[deleted];
373                 live_child[deleted] = n;
374                 if (m.pid == pid)
375                         return;
376                 n = m;
377         }
380 /*
381  * This gets called if the number of connections grows
382  * past "max_connections".
383  *
384  * We _should_ start off by searching for connections
385  * from the same IP, and if there is some address wth
386  * multiple connections, we should kill that first.
387  *
388  * As it is, we just "randomly" kill 25% of the connections,
389  * and our pseudo-random generator sucks too. I have no
390  * shame.
391  *
392  * Really, this is just a place-holder for a _real_ algorithm.
393  */
394 static void kill_some_children(int signo, unsigned start, unsigned stop)
396         start %= MAX_CHILDREN;
397         stop %= MAX_CHILDREN;
398         while (start != stop) {
399                 if (!(start & 3))
400                         kill(live_child[start].pid, signo);
401                 start = (start + 1) % MAX_CHILDREN;
402         }
405 static void check_max_connections(void)
407         for (;;) {
408                 int active;
409                 unsigned spawned, reaped, deleted;
411                 spawned = children_spawned;
412                 reaped = children_reaped;
413                 deleted = children_deleted;
415                 while (deleted < reaped) {
416                         pid_t pid = dead_child[deleted % MAX_CHILDREN];
417                         remove_child(pid, deleted, spawned);
418                         deleted++;
419                 }
420                 children_deleted = deleted;
422                 active = spawned - deleted;
423                 if (active <= max_connections)
424                         break;
426                 /* Kill some unstarted connections with SIGTERM */
427                 kill_some_children(SIGTERM, deleted, spawned);
428                 if (active <= max_connections << 1)
429                         break;
431                 /* If the SIGTERM thing isn't helping use SIGKILL */
432                 kill_some_children(SIGKILL, deleted, spawned);
433                 sleep(1);
434         }
437 static void handle(int incoming, struct sockaddr *addr, int addrlen)
439         pid_t pid = fork();
441         if (pid) {
442                 unsigned idx;
444                 close(incoming);
445                 if (pid < 0)
446                         return;
448                 idx = children_spawned % MAX_CHILDREN;
449                 children_spawned++;
450                 add_child(idx, pid, addr, addrlen);
452                 check_max_connections();
453                 return;
454         }
456         dup2(incoming, 0);
457         dup2(incoming, 1);
458         close(incoming);
460         exit(execute(addr));
463 static void child_handler(int signo)
465         for (;;) {
466                 int status;
467                 pid_t pid = waitpid(-1, &status, WNOHANG);
469                 if (pid > 0) {
470                         unsigned reaped = children_reaped;
471                         dead_child[reaped % MAX_CHILDREN] = pid;
472                         children_reaped = reaped + 1;
473                         /* XXX: Custom logging, since we don't wanna getpid() */
474                         if (verbose) {
475                                 char *dead = "";
476                                 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
477                                         dead = " (with error)";
478                                 if (log_syslog)
479                                         syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
480                                 else
481                                         fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
482                         }
483                         continue;
484                 }
485                 break;
486         }
489 static int set_reuse_addr(int sockfd)
491         int on = 1;
493         if (!reuseaddr)
494                 return 0;
495         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
496                           &on, sizeof(on));
499 #ifndef NO_IPV6
501 static int socksetup(int port, int **socklist_p)
503         int socknum = 0, *socklist = NULL;
504         int maxfd = -1;
505         char pbuf[NI_MAXSERV];
507         struct addrinfo hints, *ai0, *ai;
508         int gai;
510         sprintf(pbuf, "%d", port);
511         memset(&hints, 0, sizeof(hints));
512         hints.ai_family = AF_UNSPEC;
513         hints.ai_socktype = SOCK_STREAM;
514         hints.ai_protocol = IPPROTO_TCP;
515         hints.ai_flags = AI_PASSIVE;
517         gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
518         if (gai)
519                 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
521         for (ai = ai0; ai; ai = ai->ai_next) {
522                 int sockfd;
523                 int *newlist;
525                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
526                 if (sockfd < 0)
527                         continue;
528                 if (sockfd >= FD_SETSIZE) {
529                         error("too large socket descriptor.");
530                         close(sockfd);
531                         continue;
532                 }
534 #ifdef IPV6_V6ONLY
535                 if (ai->ai_family == AF_INET6) {
536                         int on = 1;
537                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
538                                    &on, sizeof(on));
539                         /* Note: error is not fatal */
540                 }
541 #endif
543                 if (set_reuse_addr(sockfd)) {
544                         close(sockfd);
545                         continue;
546                 }
548                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
549                         close(sockfd);
550                         continue;       /* not fatal */
551                 }
552                 if (listen(sockfd, 5) < 0) {
553                         close(sockfd);
554                         continue;       /* not fatal */
555                 }
557                 newlist = realloc(socklist, sizeof(int) * (socknum + 1));
558                 if (!newlist)
559                         die("memory allocation failed: %s", strerror(errno));
561                 socklist = newlist;
562                 socklist[socknum++] = sockfd;
564                 if (maxfd < sockfd)
565                         maxfd = sockfd;
566         }
568         freeaddrinfo(ai0);
570         *socklist_p = socklist;
571         return socknum;
574 #else /* NO_IPV6 */
576 static int socksetup(int port, int **socklist_p)
578         struct sockaddr_in sin;
579         int sockfd;
581         sockfd = socket(AF_INET, SOCK_STREAM, 0);
582         if (sockfd < 0)
583                 return 0;
585         memset(&sin, 0, sizeof sin);
586         sin.sin_family = AF_INET;
587         sin.sin_addr.s_addr = htonl(INADDR_ANY);
588         sin.sin_port = htons(port);
590         if (set_reuse_addr(sockfd)) {
591                 close(sockfd);
592                 return 0;
593         }
595         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
596                 close(sockfd);
597                 return 0;
598         }
600         if (listen(sockfd, 5) < 0) {
601                 close(sockfd);
602                 return 0;
603         }
605         *socklist_p = xmalloc(sizeof(int));
606         **socklist_p = sockfd;
607         return 1;
610 #endif
612 static int service_loop(int socknum, int *socklist)
614         struct pollfd *pfd;
615         int i;
617         pfd = xcalloc(socknum, sizeof(struct pollfd));
619         for (i = 0; i < socknum; i++) {
620                 pfd[i].fd = socklist[i];
621                 pfd[i].events = POLLIN;
622         }
624         signal(SIGCHLD, child_handler);
626         for (;;) {
627                 int i;
629                 if (poll(pfd, socknum, -1) < 0) {
630                         if (errno != EINTR) {
631                                 error("poll failed, resuming: %s",
632                                       strerror(errno));
633                                 sleep(1);
634                         }
635                         continue;
636                 }
638                 for (i = 0; i < socknum; i++) {
639                         if (pfd[i].revents & POLLIN) {
640                                 struct sockaddr_storage ss;
641                                 unsigned int sslen = sizeof(ss);
642                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
643                                 if (incoming < 0) {
644                                         switch (errno) {
645                                         case EAGAIN:
646                                         case EINTR:
647                                         case ECONNABORTED:
648                                                 continue;
649                                         default:
650                                                 die("accept returned %s", strerror(errno));
651                                         }
652                                 }
653                                 handle(incoming, (struct sockaddr *)&ss, sslen);
654                         }
655                 }
656         }
659 static int serve(int port)
661         int socknum, *socklist;
663         socknum = socksetup(port, &socklist);
664         if (socknum == 0)
665                 die("unable to allocate any listen sockets on port %u", port);
667         return service_loop(socknum, socklist);
670 int main(int argc, char **argv)
672         int port = DEFAULT_GIT_PORT;
673         int inetd_mode = 0;
674         int i;
676         for (i = 1; i < argc; i++) {
677                 char *arg = argv[i];
679                 if (!strncmp(arg, "--port=", 7)) {
680                         char *end;
681                         unsigned long n;
682                         n = strtoul(arg+7, &end, 0);
683                         if (arg[7] && !*end) {
684                                 port = n;
685                                 continue;
686                         }
687                 }
688                 if (!strcmp(arg, "--inetd")) {
689                         inetd_mode = 1;
690                         log_syslog = 1;
691                         continue;
692                 }
693                 if (!strcmp(arg, "--verbose")) {
694                         verbose = 1;
695                         continue;
696                 }
697                 if (!strcmp(arg, "--syslog")) {
698                         log_syslog = 1;
699                         continue;
700                 }
701                 if (!strcmp(arg, "--export-all")) {
702                         export_all_trees = 1;
703                         continue;
704                 }
705                 if (!strncmp(arg, "--timeout=", 10)) {
706                         timeout = atoi(arg+10);
707                         continue;
708                 }
709                 if (!strncmp(arg, "--init-timeout=", 15)) {
710                         init_timeout = atoi(arg+15);
711                         continue;
712                 }
713                 if (!strcmp(arg, "--strict-paths")) {
714                         strict_paths = 1;
715                         continue;
716                 }
717                 if (!strncmp(arg, "--base-path=", 12)) {
718                         base_path = arg+12;
719                         continue;
720                 }
721                 if (!strcmp(arg, "--reuseaddr")) {
722                         reuseaddr = 1;
723                         continue;
724                 }
725                 if (!strcmp(arg, "--user-path")) {
726                         user_path = "";
727                         continue;
728                 }
729                 if (!strncmp(arg, "--user-path=", 12)) {
730                         user_path = arg + 12;
731                         continue;
732                 }
733                 if (!strcmp(arg, "--")) {
734                         ok_paths = &argv[i+1];
735                         break;
736                 } else if (arg[0] != '-') {
737                         ok_paths = &argv[i];
738                         break;
739                 }
741                 usage(daemon_usage);
742         }
744         if (log_syslog)
745                 openlog("git-daemon", 0, LOG_DAEMON);
747         if (strict_paths && (!ok_paths || !*ok_paths)) {
748                 if (!inetd_mode)
749                         die("git-daemon: option --strict-paths requires a whitelist");
751                 logerror("option --strict-paths requires a whitelist");
752                 exit (1);
753         }
755         if (inetd_mode) {
756                 struct sockaddr_storage ss;
757                 struct sockaddr *peer = (struct sockaddr *)&ss;
758                 socklen_t slen = sizeof(ss);
760                 fclose(stderr); //FIXME: workaround
762                 if (getpeername(0, peer, &slen))
763                         peer = NULL;
765                 return execute(peer);
766         }
768         return serve(port);