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] [--detach] [--pid-file=file] [directory...]";
24 /* List of acceptable pathname prefixes */
25 static char **ok_paths
;
26 static int strict_paths
;
28 /* If this is set, git-daemon-export-ok is not required */
29 static int export_all_trees
;
31 /* Take all paths relative to this one if non-NULL */
32 static char *base_path
;
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
;
40 /* Timeout, and initial timeout */
41 static unsigned int timeout
;
42 static unsigned int init_timeout
;
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
;
337 static pid_t dead_child
[MAX_CHILDREN
];
339 /* These are updated by the main loop */
340 static unsigned int children_spawned
;
341 static unsigned int children_deleted
;
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
);