Provide git_config with a callback-data parameter
[git/git.git] / daemon.c
CommitLineData
979e32fa 1#include "cache.h"
85023577 2#include "pkt-line.h"
77cb17e9 3#include "exec_cmd.h"
49ba83fb 4#include "interpolate.h"
f8ff0c06 5
85023577
JH
6#include <syslog.h>
7
695dffe2
JS
8#ifndef HOST_NAME_MAX
9#define HOST_NAME_MAX 256
10#endif
11
415e7b87
PW
12#ifndef NI_MAXSERV
13#define NI_MAXSERV 32
14#endif
15
9048fe1c 16static int log_syslog;
f8ff0c06 17static int verbose;
1955fabf 18static int reuseaddr;
f8ff0c06 19
960deccb 20static const char daemon_usage[] =
dd467629 21"git-daemon [--verbose] [--syslog] [--export-all]\n"
b21c31c9 22" [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
73a7a656
JA
23" [--base-path=path] [--base-path-relaxed]\n"
24" [--user-path | --user-path=path]\n"
49ba83fb 25" [--interpolated-path=path]\n"
678dac6b 26" [--reuseaddr] [--detach] [--pid-file=file]\n"
d9edcbd6 27" [--[enable|disable|allow-override|forbid-override]=service]\n"
dd467629
JL
28" [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
29" [--user=user [--group=group]]\n"
30" [directory...]";
4ae95682
PA
31
32/* List of acceptable pathname prefixes */
96f1e58f
DR
33static char **ok_paths;
34static int strict_paths;
4ae95682
PA
35
36/* If this is set, git-daemon-export-ok is not required */
96f1e58f 37static int export_all_trees;
f8ff0c06 38
b21c31c9 39/* Take all paths relative to this one if non-NULL */
96f1e58f 40static char *base_path;
49ba83fb 41static char *interpolated_path;
73a7a656 42static int base_path_relaxed;
49ba83fb
JL
43
44/* Flag indicating client sent extra args. */
45static int saw_extended_args;
b21c31c9 46
603968d2
JH
47/* If defined, ~user notation is allowed and the string is inserted
48 * after ~user/. E.g. a request to git://host/~alice/frotz would
49 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
50 */
96f1e58f 51static const char *user_path;
603968d2 52
960deccb 53/* Timeout, and initial timeout */
96f1e58f
DR
54static unsigned int timeout;
55static unsigned int init_timeout;
f8ff0c06 56
49ba83fb
JL
57/*
58 * Static table for now. Ugh.
59 * Feel free to make dynamic as needed.
60 */
61#define INTERP_SLOT_HOST (0)
dd467629
JL
62#define INTERP_SLOT_CANON_HOST (1)
63#define INTERP_SLOT_IP (2)
64#define INTERP_SLOT_PORT (3)
65#define INTERP_SLOT_DIR (4)
66#define INTERP_SLOT_PERCENT (5)
49ba83fb
JL
67
68static struct interp interp_table[] = {
69 { "%H", 0},
dd467629
JL
70 { "%CH", 0},
71 { "%IP", 0},
72 { "%P", 0},
49ba83fb 73 { "%D", 0},
eb30aed7 74 { "%%", 0},
49ba83fb
JL
75};
76
77
9048fe1c 78static void logreport(int priority, const char *err, va_list params)
f8ff0c06
PB
79{
80 /* We should do a single write so that it is atomic and output
81 * of several processes do not get intermingled. */
82 char buf[1024];
83 int buflen;
84 int maxlen, msglen;
85
86 /* sizeof(buf) should be big enough for "[pid] \n" */
1bedd4ca 87 buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
f8ff0c06
PB
88
89 maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
90 msglen = vsnprintf(buf + buflen, maxlen, err, params);
91
9048fe1c
PB
92 if (log_syslog) {
93 syslog(priority, "%s", buf);
94 return;
95 }
96
f8ff0c06
PB
97 /* maxlen counted our own LF but also counts space given to
98 * vsnprintf for the terminating NUL. We want to make sure that
99 * we have space for our own LF and NUL after the "meat" of the
100 * message, so truncate it at maxlen - 1.
101 */
102 if (msglen > maxlen - 1)
103 msglen = maxlen - 1;
104 else if (msglen < 0)
105 msglen = 0; /* Protect against weird return values. */
106 buflen += msglen;
107
108 buf[buflen++] = '\n';
109 buf[buflen] = '\0';
110
93822c22 111 write_in_full(2, buf, buflen);
f8ff0c06
PB
112}
113
cdda4745 114static void logerror(const char *err, ...)
f8ff0c06
PB
115{
116 va_list params;
117 va_start(params, err);
9048fe1c 118 logreport(LOG_ERR, err, params);
f8ff0c06
PB
119 va_end(params);
120}
121
cdda4745 122static void loginfo(const char *err, ...)
f8ff0c06
PB
123{
124 va_list params;
125 if (!verbose)
126 return;
127 va_start(params, err);
9048fe1c 128 logreport(LOG_INFO, err, params);
f8ff0c06
PB
129 va_end(params);
130}
a87e8be2 131
ad8b4f56
ML
132static void NORETURN daemon_die(const char *err, va_list params)
133{
134 logreport(LOG_ERR, err, params);
135 exit(1);
136}
137
d79374c7
JH
138static int avoid_alias(char *p)
139{
140 int sl, ndot;
141
a6080a0a 142 /*
d79374c7
JH
143 * This resurrects the belts and suspenders paranoia check by HPA
144 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
145 * does not do getcwd() based path canonicalizations.
146 *
147 * sl becomes true immediately after seeing '/' and continues to
148 * be true as long as dots continue after that without intervening
149 * non-dot character.
150 */
151 if (!p || (*p != '/' && *p != '~'))
152 return -1;
153 sl = 1; ndot = 0;
154 p++;
155
156 while (1) {
157 char ch = *p++;
158 if (sl) {
159 if (ch == '.')
160 ndot++;
161 else if (ch == '/') {
162 if (ndot < 3)
163 /* reject //, /./ and /../ */
164 return -1;
165 ndot = 0;
166 }
167 else if (ch == 0) {
168 if (0 < ndot && ndot < 3)
169 /* reject /.$ and /..$ */
170 return -1;
171 return 0;
172 }
173 else
174 sl = ndot = 0;
175 }
176 else if (ch == 0)
177 return 0;
178 else if (ch == '/') {
179 sl = 1;
180 ndot = 0;
181 }
182 }
183}
184
49ba83fb 185static char *path_ok(struct interp *itable)
4ae95682 186{
603968d2 187 static char rpath[PATH_MAX];
49ba83fb 188 static char interp_path[PATH_MAX];
73a7a656 189 int retried_path = 0;
d79374c7 190 char *path;
49ba83fb
JL
191 char *dir;
192
193 dir = itable[INTERP_SLOT_DIR].value;
d79374c7
JH
194
195 if (avoid_alias(dir)) {
196 logerror("'%s': aliased", dir);
197 return NULL;
198 }
199
603968d2
JH
200 if (*dir == '~') {
201 if (!user_path) {
202 logerror("'%s': User-path not allowed", dir);
203 return NULL;
204 }
205 if (*user_path) {
206 /* Got either "~alice" or "~alice/foo";
207 * rewrite them to "~alice/%s" or
208 * "~alice/%s/foo".
209 */
210 int namlen, restlen = strlen(dir);
211 char *slash = strchr(dir, '/');
212 if (!slash)
213 slash = dir + restlen;
214 namlen = slash - dir;
215 restlen -= namlen;
216 loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
217 snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
218 namlen, dir, user_path, restlen, slash);
219 dir = rpath;
220 }
221 }
49ba83fb
JL
222 else if (interpolated_path && saw_extended_args) {
223 if (*dir != '/') {
224 /* Allow only absolute */
225 logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
226 return NULL;
227 }
228
229 interpolate(interp_path, PATH_MAX, interpolated_path,
230 interp_table, ARRAY_SIZE(interp_table));
231 loginfo("Interpolated dir '%s'", interp_path);
232
233 dir = interp_path;
234 }
603968d2
JH
235 else if (base_path) {
236 if (*dir != '/') {
237 /* Allow only absolute */
1fda3d55 238 logerror("'%s': Non-absolute path denied (base-path active)", dir);
b21c31c9
PB
239 return NULL;
240 }
49ba83fb
JL
241 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
242 dir = rpath;
b21c31c9
PB
243 }
244
73a7a656
JA
245 do {
246 path = enter_repo(dir, strict_paths);
247 if (path)
248 break;
249
250 /*
251 * if we fail and base_path_relaxed is enabled, try without
252 * prefixing the base path
253 */
254 if (base_path && base_path_relaxed && !retried_path) {
255 dir = itable[INTERP_SLOT_DIR].value;
256 retried_path = 1;
257 continue;
258 }
259 break;
260 } while (1);
3e04c62d 261
4dbd1352
AE
262 if (!path) {
263 logerror("'%s': unable to chdir or not a git archive", dir);
264 return NULL;
4ae95682
PA
265 }
266
267 if ( ok_paths && *ok_paths ) {
ce335fe0 268 char **pp;
4dbd1352 269 int pathlen = strlen(path);
4ae95682 270
ce335fe0 271 /* The validation is done on the paths after enter_repo
a6080a0a 272 * appends optional {.git,.git/.git} and friends, but
d79374c7
JH
273 * it does not use getcwd(). So if your /pub is
274 * a symlink to /mnt/pub, you can whitelist /pub and
275 * do not have to say /mnt/pub.
276 * Do not say /pub/.
ce335fe0 277 */
4ae95682
PA
278 for ( pp = ok_paths ; *pp ; pp++ ) {
279 int len = strlen(*pp);
ce335fe0
JH
280 if (len <= pathlen &&
281 !memcmp(*pp, path, len) &&
282 (path[len] == '\0' ||
283 (!strict_paths && path[len] == '/')))
284 return path;
4ae95682 285 }
4dbd1352
AE
286 }
287 else {
288 /* be backwards compatible */
289 if (!strict_paths)
290 return path;
4ae95682
PA
291 }
292
4dbd1352
AE
293 logerror("'%s': not in whitelist", path);
294 return NULL; /* Fallthrough. Deny by default */
4ae95682 295}
a87e8be2 296
d819e4e6
JH
297typedef int (*daemon_service_fn)(void);
298struct daemon_service {
299 const char *name;
300 const char *config_name;
301 daemon_service_fn fn;
302 int enabled;
303 int overridable;
304};
305
306static struct daemon_service *service_looking_at;
307static int service_enabled;
308
ef90d6d4 309static int git_daemon_config(const char *var, const char *value, void *cb)
d819e4e6 310{
cc44c765 311 if (!prefixcmp(var, "daemon.") &&
d819e4e6
JH
312 !strcmp(var + 7, service_looking_at->config_name)) {
313 service_enabled = git_config_bool(var, value);
314 return 0;
315 }
316
317 /* we are not interested in parsing any other configuration here */
318 return 0;
319}
320
49ba83fb 321static int run_service(struct interp *itable, struct daemon_service *service)
a87e8be2 322{
4dbd1352 323 const char *path;
d819e4e6
JH
324 int enabled = service->enabled;
325
49ba83fb
JL
326 loginfo("Request %s for '%s'",
327 service->name,
328 itable[INTERP_SLOT_DIR].value);
4dbd1352 329
d819e4e6
JH
330 if (!enabled && !service->overridable) {
331 logerror("'%s': service not enabled.", service->name);
332 errno = EACCES;
333 return -1;
334 }
4ae95682 335
49ba83fb 336 if (!(path = path_ok(itable)))
a87e8be2 337 return -1;
47888f0f 338
a87e8be2
LT
339 /*
340 * Security on the cheap.
341 *
a935c397 342 * We want a readable HEAD, usable "objects" directory, and
a87e8be2
LT
343 * a "git-daemon-export-ok" flag that says that the other side
344 * is ok with us doing this.
4dbd1352
AE
345 *
346 * path_ok() uses enter_repo() and does whitelist checking.
347 * We only need to make sure the repository is exported.
a87e8be2 348 */
4dbd1352 349
3e04c62d 350 if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
4dbd1352 351 logerror("'%s': repository not exported.", path);
3e04c62d
PA
352 errno = EACCES;
353 return -1;
354 }
355
d819e4e6
JH
356 if (service->overridable) {
357 service_looking_at = service;
358 service_enabled = -1;
ef90d6d4 359 git_config(git_daemon_config, NULL);
d819e4e6
JH
360 if (0 <= service_enabled)
361 enabled = service_enabled;
362 }
363 if (!enabled) {
364 logerror("'%s': service not enabled for '%s'",
365 service->name, path);
366 errno = EACCES;
367 return -1;
368 }
369
02d57da4
LT
370 /*
371 * We'll ignore SIGTERM from now on, we have a
372 * good client.
373 */
374 signal(SIGTERM, SIG_IGN);
375
d819e4e6
JH
376 return service->fn();
377}
378
379static int upload_pack(void)
380{
381 /* Timeout as string */
382 char timeout_buf[64];
383
960deccb
PA
384 snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
385
a87e8be2 386 /* git-upload-pack only ever reads stuff, so this is safe */
77cb17e9 387 execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
a87e8be2
LT
388 return -1;
389}
390
39345a21
FBH
391static int upload_archive(void)
392{
393 execl_git_cmd("upload-archive", ".", NULL);
394 return -1;
395}
396
4b3b1e1e
LT
397static int receive_pack(void)
398{
399 execl_git_cmd("receive-pack", ".", NULL);
400 return -1;
401}
402
d819e4e6 403static struct daemon_service daemon_service[] = {
39345a21 404 { "upload-archive", "uploadarch", upload_archive, 0, 1 },
d819e4e6 405 { "upload-pack", "uploadpack", upload_pack, 1, 1 },
4b3b1e1e 406 { "receive-pack", "receivepack", receive_pack, 0, 1 },
d819e4e6
JH
407};
408
f3fa1838
JH
409static void enable_service(const char *name, int ena)
410{
d819e4e6
JH
411 int i;
412 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
413 if (!strcmp(daemon_service[i].name, name)) {
414 daemon_service[i].enabled = ena;
415 return;
416 }
417 }
418 die("No such service %s", name);
419}
420
f3fa1838
JH
421static void make_service_overridable(const char *name, int ena)
422{
d819e4e6
JH
423 int i;
424 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
425 if (!strcmp(daemon_service[i].name, name)) {
426 daemon_service[i].overridable = ena;
427 return;
428 }
429 }
430 die("No such service %s", name);
431}
432
eb30aed7
JL
433/*
434 * Separate the "extra args" information as supplied by the client connection.
3dff5379 435 * Any resulting data is squirreled away in the given interpolation table.
eb30aed7
JL
436 */
437static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
49ba83fb
JL
438{
439 char *val;
440 int vallen;
441 char *end = extra_args + buflen;
442
443 while (extra_args < end && *extra_args) {
444 saw_extended_args = 1;
445 if (strncasecmp("host=", extra_args, 5) == 0) {
446 val = extra_args + 5;
447 vallen = strlen(val) + 1;
448 if (*val) {
eb30aed7
JL
449 /* Split <host>:<port> at colon. */
450 char *host = val;
451 char *port = strrchr(host, ':');
dd467629
JL
452 if (port) {
453 *port = 0;
454 port++;
eb30aed7 455 interp_set_entry(table, INTERP_SLOT_PORT, port);
dd467629 456 }
eb30aed7 457 interp_set_entry(table, INTERP_SLOT_HOST, host);
49ba83fb 458 }
eb30aed7 459
49ba83fb
JL
460 /* On to the next one */
461 extra_args = val + vallen;
462 }
463 }
464}
465
52fae7de 466static void fill_in_extra_table_entries(struct interp *itable)
dd467629
JL
467{
468 char *hp;
dd467629
JL
469
470 /*
471 * Replace literal host with lowercase-ized hostname.
472 */
473 hp = interp_table[INTERP_SLOT_HOST].value;
83543a24
JH
474 if (!hp)
475 return;
dd467629
JL
476 for ( ; *hp; hp++)
477 *hp = tolower(*hp);
478
479 /*
480 * Locate canonical hostname and its IP address.
481 */
482#ifndef NO_IPV6
483 {
484 struct addrinfo hints;
485 struct addrinfo *ai, *ai0;
486 int gai;
487 static char addrbuf[HOST_NAME_MAX + 1];
488
489 memset(&hints, 0, sizeof(hints));
490 hints.ai_flags = AI_CANONNAME;
491
492 gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
493 if (!gai) {
494 for (ai = ai0; ai; ai = ai->ai_next) {
495 struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
496
dd467629
JL
497 inet_ntop(AF_INET, &sin_addr->sin_addr,
498 addrbuf, sizeof(addrbuf));
eb30aed7
JL
499 interp_set_entry(interp_table,
500 INTERP_SLOT_CANON_HOST, ai->ai_canonname);
501 interp_set_entry(interp_table,
502 INTERP_SLOT_IP, addrbuf);
dd467629
JL
503 break;
504 }
505 freeaddrinfo(ai0);
506 }
507 }
508#else
509 {
510 struct hostent *hent;
511 struct sockaddr_in sa;
512 char **ap;
513 static char addrbuf[HOST_NAME_MAX + 1];
514
515 hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
dd467629
JL
516
517 ap = hent->h_addr_list;
518 memset(&sa, 0, sizeof sa);
519 sa.sin_family = hent->h_addrtype;
520 sa.sin_port = htons(0);
521 memcpy(&sa.sin_addr, *ap, hent->h_length);
522
523 inet_ntop(hent->h_addrtype, &sa.sin_addr,
524 addrbuf, sizeof(addrbuf));
eb30aed7
JL
525
526 interp_set_entry(interp_table, INTERP_SLOT_CANON_HOST, hent->h_name);
527 interp_set_entry(interp_table, INTERP_SLOT_IP, addrbuf);
dd467629
JL
528 }
529#endif
dd467629
JL
530}
531
532
5b276ee4 533static int execute(struct sockaddr *addr)
a87e8be2 534{
7d80694a 535 static char line[1000];
d819e4e6 536 int pktlen, len, i;
7d80694a 537
5b276ee4
DW
538 if (addr) {
539 char addrbuf[256] = "";
540 int port = -1;
541
542 if (addr->sa_family == AF_INET) {
543 struct sockaddr_in *sin_addr = (void *) addr;
544 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
c67359be 545 port = ntohs(sin_addr->sin_port);
5b276ee4
DW
546#ifndef NO_IPV6
547 } else if (addr && addr->sa_family == AF_INET6) {
548 struct sockaddr_in6 *sin6_addr = (void *) addr;
549
550 char *buf = addrbuf;
551 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
552 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
553 strcat(buf, "]");
554
c67359be 555 port = ntohs(sin6_addr->sin6_port);
5b276ee4
DW
556#endif
557 }
558 loginfo("Connection from %s:%d", addrbuf, port);
559 }
560
960deccb 561 alarm(init_timeout ? init_timeout : timeout);
5ad312be 562 pktlen = packet_read_line(0, line, sizeof(line));
960deccb 563 alarm(0);
7d80694a 564
5ad312be
JL
565 len = strlen(line);
566 if (pktlen != len)
567 loginfo("Extended attributes (%d bytes) exist <%.*s>",
568 (int) pktlen - len,
569 (int) pktlen - len, line + len + 1);
83543a24 570 if (len && line[len-1] == '\n') {
7d80694a 571 line[--len] = 0;
83543a24
JH
572 pktlen--;
573 }
7d80694a 574
eb30aed7
JL
575 /*
576 * Initialize the path interpolation table for this connection.
577 */
578 interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
579 interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
580
dd467629 581 if (len != pktlen) {
eb30aed7 582 parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
dd467629
JL
583 fill_in_extra_table_entries(interp_table);
584 }
49ba83fb 585
d819e4e6
JH
586 for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
587 struct daemon_service *s = &(daemon_service[i]);
588 int namelen = strlen(s->name);
599065a3 589 if (!prefixcmp(line, "git-") &&
d819e4e6 590 !strncmp(s->name, line + 4, namelen) &&
49ba83fb 591 line[namelen + 4] == ' ') {
eb30aed7
JL
592 /*
593 * Note: The directory here is probably context sensitive,
594 * and might depend on the actual service being performed.
595 */
596 interp_set_entry(interp_table,
597 INTERP_SLOT_DIR, line + namelen + 5);
49ba83fb
JL
598 return run_service(interp_table, s);
599 }
d819e4e6 600 }
a87e8be2 601
f8ff0c06 602 logerror("Protocol error: '%s'", line);
a87e8be2
LT
603 return -1;
604}
605
66e631de
LT
606
607/*
608 * We count spawned/reaped separately, just to avoid any
609 * races when updating them from signals. The SIGCHLD handler
610 * will only update children_reaped, and the fork logic will
611 * only update children_spawned.
612 *
613 * MAX_CHILDREN should be a power-of-two to make the modulus
614 * operation cheap. It should also be at least twice
615 * the maximum number of connections we will ever allow.
616 */
617#define MAX_CHILDREN 128
618
619static int max_connections = 25;
620
621/* These are updated by the signal handler */
96f1e58f 622static volatile unsigned int children_reaped;
4d8fa916 623static pid_t dead_child[MAX_CHILDREN];
66e631de
LT
624
625/* These are updated by the main loop */
96f1e58f
DR
626static unsigned int children_spawned;
627static unsigned int children_deleted;
66e631de 628
4d8fa916 629static struct child {
66e631de 630 pid_t pid;
7fa09084 631 int addrlen;
df076bdb 632 struct sockaddr_storage address;
66e631de
LT
633} live_child[MAX_CHILDREN];
634
7fa09084 635static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
66e631de
LT
636{
637 live_child[idx].pid = pid;
638 live_child[idx].addrlen = addrlen;
df076bdb 639 memcpy(&live_child[idx].address, addr, addrlen);
66e631de
LT
640}
641
642/*
643 * Walk from "deleted" to "spawned", and remove child "pid".
644 *
645 * We move everything up by one, since the new "deleted" will
646 * be one higher.
647 */
648static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
649{
650 struct child n;
651
652 deleted %= MAX_CHILDREN;
653 spawned %= MAX_CHILDREN;
654 if (live_child[deleted].pid == pid) {
655 live_child[deleted].pid = -1;
656 return;
657 }
658 n = live_child[deleted];
659 for (;;) {
660 struct child m;
661 deleted = (deleted + 1) % MAX_CHILDREN;
662 if (deleted == spawned)
663 die("could not find dead child %d\n", pid);
664 m = live_child[deleted];
665 live_child[deleted] = n;
666 if (m.pid == pid)
667 return;
668 n = m;
669 }
670}
671
672/*
673 * This gets called if the number of connections grows
674 * past "max_connections".
675 *
676 * We _should_ start off by searching for connections
677 * from the same IP, and if there is some address wth
678 * multiple connections, we should kill that first.
679 *
680 * As it is, we just "randomly" kill 25% of the connections,
681 * and our pseudo-random generator sucks too. I have no
682 * shame.
683 *
684 * Really, this is just a place-holder for a _real_ algorithm.
685 */
02d57da4 686static void kill_some_children(int signo, unsigned start, unsigned stop)
66e631de
LT
687{
688 start %= MAX_CHILDREN;
689 stop %= MAX_CHILDREN;
690 while (start != stop) {
691 if (!(start & 3))
02d57da4 692 kill(live_child[start].pid, signo);
66e631de
LT
693 start = (start + 1) % MAX_CHILDREN;
694 }
695}
696
02d57da4 697static void check_max_connections(void)
a87e8be2 698{
02d57da4 699 for (;;) {
eaa94919 700 int active;
66e631de 701 unsigned spawned, reaped, deleted;
eaa94919 702
66e631de 703 spawned = children_spawned;
66e631de
LT
704 reaped = children_reaped;
705 deleted = children_deleted;
706
707 while (deleted < reaped) {
708 pid_t pid = dead_child[deleted % MAX_CHILDREN];
709 remove_child(pid, deleted, spawned);
710 deleted++;
711 }
712 children_deleted = deleted;
713
714 active = spawned - deleted;
02d57da4
LT
715 if (active <= max_connections)
716 break;
66e631de 717
02d57da4
LT
718 /* Kill some unstarted connections with SIGTERM */
719 kill_some_children(SIGTERM, deleted, spawned);
720 if (active <= max_connections << 1)
721 break;
722
723 /* If the SIGTERM thing isn't helping use SIGKILL */
724 kill_some_children(SIGKILL, deleted, spawned);
725 sleep(1);
726 }
727}
728
7fa09084 729static void handle(int incoming, struct sockaddr *addr, int addrlen)
02d57da4
LT
730{
731 pid_t pid = fork();
732
733 if (pid) {
734 unsigned idx;
735
736 close(incoming);
737 if (pid < 0)
738 return;
739
740 idx = children_spawned % MAX_CHILDREN;
741 children_spawned++;
742 add_child(idx, pid, addr, addrlen);
66e631de 743
02d57da4 744 check_max_connections();
a87e8be2
LT
745 return;
746 }
747
748 dup2(incoming, 0);
749 dup2(incoming, 1);
750 close(incoming);
f8ff0c06 751
5b276ee4 752 exit(execute(addr));
a87e8be2
LT
753}
754
eaa94919
LT
755static void child_handler(int signo)
756{
757 for (;;) {
9048fe1c
PB
758 int status;
759 pid_t pid = waitpid(-1, &status, WNOHANG);
66e631de
LT
760
761 if (pid > 0) {
762 unsigned reaped = children_reaped;
763 dead_child[reaped % MAX_CHILDREN] = pid;
764 children_reaped = reaped + 1;
f8ff0c06 765 /* XXX: Custom logging, since we don't wanna getpid() */
9048fe1c 766 if (verbose) {
554fe20d 767 const char *dead = "";
9048fe1c
PB
768 if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
769 dead = " (with error)";
770 if (log_syslog)
771 syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
772 else
773 fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
774 }
eaa94919
LT
775 continue;
776 }
777 break;
778 }
779}
780
1955fabf
MW
781static int set_reuse_addr(int sockfd)
782{
783 int on = 1;
784
785 if (!reuseaddr)
786 return 0;
787 return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
788 &on, sizeof(on));
789}
790
6573faff
PA
791#ifndef NO_IPV6
792
dd467629 793static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
a87e8be2 794{
df076bdb
YH
795 int socknum = 0, *socklist = NULL;
796 int maxfd = -1;
df076bdb 797 char pbuf[NI_MAXSERV];
6573faff
PA
798 struct addrinfo hints, *ai0, *ai;
799 int gai;
20276889 800 long flags;
df076bdb 801
dd467629 802 sprintf(pbuf, "%d", listen_port);
df076bdb
YH
803 memset(&hints, 0, sizeof(hints));
804 hints.ai_family = AF_UNSPEC;
805 hints.ai_socktype = SOCK_STREAM;
806 hints.ai_protocol = IPPROTO_TCP;
807 hints.ai_flags = AI_PASSIVE;
808
dd467629 809 gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
df076bdb
YH
810 if (gai)
811 die("getaddrinfo() failed: %s\n", gai_strerror(gai));
812
df076bdb
YH
813 for (ai = ai0; ai; ai = ai->ai_next) {
814 int sockfd;
df076bdb
YH
815
816 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
817 if (sockfd < 0)
818 continue;
819 if (sockfd >= FD_SETSIZE) {
820 error("too large socket descriptor.");
821 close(sockfd);
822 continue;
823 }
824
825#ifdef IPV6_V6ONLY
826 if (ai->ai_family == AF_INET6) {
827 int on = 1;
828 setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
829 &on, sizeof(on));
830 /* Note: error is not fatal */
831 }
832#endif
833
1955fabf
MW
834 if (set_reuse_addr(sockfd)) {
835 close(sockfd);
0032d548 836 continue;
1955fabf
MW
837 }
838
df076bdb
YH
839 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
840 close(sockfd);
841 continue; /* not fatal */
842 }
843 if (listen(sockfd, 5) < 0) {
844 close(sockfd);
845 continue; /* not fatal */
846 }
847
20276889
AJ
848 flags = fcntl(sockfd, F_GETFD, 0);
849 if (flags >= 0)
850 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
851
83572c1a 852 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
df076bdb
YH
853 socklist[socknum++] = sockfd;
854
df076bdb
YH
855 if (maxfd < sockfd)
856 maxfd = sockfd;
857 }
858
859 freeaddrinfo(ai0);
860
6573faff
PA
861 *socklist_p = socklist;
862 return socknum;
863}
864
865#else /* NO_IPV6 */
866
100690b6 867static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
6573faff
PA
868{
869 struct sockaddr_in sin;
870 int sockfd;
20276889 871 long flags;
6573faff 872
dd467629
JL
873 memset(&sin, 0, sizeof sin);
874 sin.sin_family = AF_INET;
875 sin.sin_port = htons(listen_port);
876
877 if (listen_addr) {
878 /* Well, host better be an IP address here. */
879 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
880 return 0;
881 } else {
882 sin.sin_addr.s_addr = htonl(INADDR_ANY);
883 }
884
6573faff
PA
885 sockfd = socket(AF_INET, SOCK_STREAM, 0);
886 if (sockfd < 0)
887 return 0;
888
1955fabf
MW
889 if (set_reuse_addr(sockfd)) {
890 close(sockfd);
891 return 0;
892 }
893
6573faff
PA
894 if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
895 close(sockfd);
896 return 0;
897 }
a87e8be2 898
f35230fb
PS
899 if (listen(sockfd, 5) < 0) {
900 close(sockfd);
901 return 0;
902 }
903
20276889
AJ
904 flags = fcntl(sockfd, F_GETFD, 0);
905 if (flags >= 0)
906 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
907
1b4713fb 908 *socklist_p = xmalloc(sizeof(int));
6573faff 909 **socklist_p = sockfd;
f35230fb 910 return 1;
6573faff
PA
911}
912
913#endif
914
915static int service_loop(int socknum, int *socklist)
916{
917 struct pollfd *pfd;
918 int i;
919
1b4713fb 920 pfd = xcalloc(socknum, sizeof(struct pollfd));
6573faff
PA
921
922 for (i = 0; i < socknum; i++) {
923 pfd[i].fd = socklist[i];
924 pfd[i].events = POLLIN;
925 }
9220282a
PA
926
927 signal(SIGCHLD, child_handler);
a87e8be2
LT
928
929 for (;;) {
df076bdb 930 int i;
6573faff 931
7872e055 932 if (poll(pfd, socknum, -1) < 0) {
1eef0b33 933 if (errno != EINTR) {
6573faff 934 error("poll failed, resuming: %s",
1eef0b33
JH
935 strerror(errno));
936 sleep(1);
937 }
df076bdb
YH
938 continue;
939 }
940
941 for (i = 0; i < socknum; i++) {
6573faff 942 if (pfd[i].revents & POLLIN) {
df076bdb 943 struct sockaddr_storage ss;
7626e49e 944 unsigned int sslen = sizeof(ss);
6573faff 945 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
df076bdb
YH
946 if (incoming < 0) {
947 switch (errno) {
948 case EAGAIN:
949 case EINTR:
950 case ECONNABORTED:
951 continue;
952 default:
953 die("accept returned %s", strerror(errno));
954 }
955 }
956 handle(incoming, (struct sockaddr *)&ss, sslen);
a87e8be2
LT
957 }
958 }
a87e8be2
LT
959 }
960}
961
258e93a1
ML
962/* if any standard file descriptor is missing open it to /dev/null */
963static void sanitize_stdfds(void)
964{
965 int fd = open("/dev/null", O_RDWR, 0);
966 while (fd != -1 && fd < 2)
967 fd = dup(fd);
968 if (fd == -1)
969 die("open /dev/null or dup failed: %s", strerror(errno));
970 if (fd > 2)
971 close(fd);
972}
973
a5262768
ML
974static void daemonize(void)
975{
976 switch (fork()) {
977 case 0:
978 break;
979 case -1:
980 die("fork failed: %s", strerror(errno));
981 default:
982 exit(0);
983 }
984 if (setsid() == -1)
985 die("setsid failed: %s", strerror(errno));
986 close(0);
987 close(1);
988 close(2);
989 sanitize_stdfds();
990}
991
45ed5d7f
ML
992static void store_pid(const char *path)
993{
994 FILE *f = fopen(path, "w");
995 if (!f)
996 die("cannot open pid file %s: %s", path, strerror(errno));
bc4e7d03
JM
997 if (fprintf(f, "%d\n", getpid()) < 0 || fclose(f) != 0)
998 die("failed to write pid file %s: %s", path, strerror(errno));
45ed5d7f
ML
999}
1000
dd467629 1001static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
6573faff
PA
1002{
1003 int socknum, *socklist;
4ae22d96 1004
dd467629 1005 socknum = socksetup(listen_addr, listen_port, &socklist);
6573faff 1006 if (socknum == 0)
dd467629
JL
1007 die("unable to allocate any listen sockets on host %s port %u",
1008 listen_addr, listen_port);
4ae22d96 1009
678dac6b
TS
1010 if (pass && gid &&
1011 (initgroups(pass->pw_name, gid) || setgid (gid) ||
1012 setuid(pass->pw_uid)))
1013 die("cannot drop privileges");
1014
6573faff 1015 return service_loop(socknum, socklist);
4ae22d96 1016}
6573faff 1017
a87e8be2
LT
1018int main(int argc, char **argv)
1019{
dd467629
JL
1020 int listen_port = 0;
1021 char *listen_addr = NULL;
e64e1b79 1022 int inetd_mode = 0;
678dac6b 1023 const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
a5262768 1024 int detach = 0;
678dac6b
TS
1025 struct passwd *pass = NULL;
1026 struct group *group;
1027 gid_t gid = 0;
a87e8be2
LT
1028 int i;
1029
f0b7367c
JH
1030 /* Without this we cannot rely on waitpid() to tell
1031 * what happened to our children.
1032 */
1033 signal(SIGCHLD, SIG_DFL);
1034
a87e8be2
LT
1035 for (i = 1; i < argc; i++) {
1036 char *arg = argv[i];
1037
cc44c765 1038 if (!prefixcmp(arg, "--listen=")) {
dd467629
JL
1039 char *p = arg + 9;
1040 char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
1041 while (*p)
1042 *ph++ = tolower(*p++);
1043 *ph = 0;
1044 continue;
1045 }
cc44c765 1046 if (!prefixcmp(arg, "--port=")) {
a87e8be2
LT
1047 char *end;
1048 unsigned long n;
1049 n = strtoul(arg+7, &end, 0);
1050 if (arg[7] && !*end) {
dd467629 1051 listen_port = n;
a87e8be2
LT
1052 continue;
1053 }
1054 }
e64e1b79
LT
1055 if (!strcmp(arg, "--inetd")) {
1056 inetd_mode = 1;
a8883288 1057 log_syslog = 1;
e64e1b79
LT
1058 continue;
1059 }
f8ff0c06
PB
1060 if (!strcmp(arg, "--verbose")) {
1061 verbose = 1;
1062 continue;
1063 }
9048fe1c
PB
1064 if (!strcmp(arg, "--syslog")) {
1065 log_syslog = 1;
9048fe1c
PB
1066 continue;
1067 }
4ae95682
PA
1068 if (!strcmp(arg, "--export-all")) {
1069 export_all_trees = 1;
1070 continue;
1071 }
cc44c765 1072 if (!prefixcmp(arg, "--timeout=")) {
960deccb 1073 timeout = atoi(arg+10);
a8883288 1074 continue;
960deccb 1075 }
cc44c765 1076 if (!prefixcmp(arg, "--init-timeout=")) {
960deccb 1077 init_timeout = atoi(arg+15);
a8883288 1078 continue;
960deccb 1079 }
4dbd1352
AE
1080 if (!strcmp(arg, "--strict-paths")) {
1081 strict_paths = 1;
1082 continue;
1083 }
cc44c765 1084 if (!prefixcmp(arg, "--base-path=")) {
b21c31c9
PB
1085 base_path = arg+12;
1086 continue;
1087 }
73a7a656
JA
1088 if (!strcmp(arg, "--base-path-relaxed")) {
1089 base_path_relaxed = 1;
1090 continue;
1091 }
cc44c765 1092 if (!prefixcmp(arg, "--interpolated-path=")) {
49ba83fb
JL
1093 interpolated_path = arg+20;
1094 continue;
1095 }
1955fabf
MW
1096 if (!strcmp(arg, "--reuseaddr")) {
1097 reuseaddr = 1;
1098 continue;
1099 }
603968d2
JH
1100 if (!strcmp(arg, "--user-path")) {
1101 user_path = "";
1102 continue;
1103 }
cc44c765 1104 if (!prefixcmp(arg, "--user-path=")) {
603968d2
JH
1105 user_path = arg + 12;
1106 continue;
1107 }
cc44c765 1108 if (!prefixcmp(arg, "--pid-file=")) {
45ed5d7f
ML
1109 pid_file = arg + 11;
1110 continue;
1111 }
a5262768
ML
1112 if (!strcmp(arg, "--detach")) {
1113 detach = 1;
1114 log_syslog = 1;
1115 continue;
1116 }
cc44c765 1117 if (!prefixcmp(arg, "--user=")) {
678dac6b
TS
1118 user_name = arg + 7;
1119 continue;
1120 }
cc44c765 1121 if (!prefixcmp(arg, "--group=")) {
678dac6b
TS
1122 group_name = arg + 8;
1123 continue;
1124 }
cc44c765 1125 if (!prefixcmp(arg, "--enable=")) {
d819e4e6
JH
1126 enable_service(arg + 9, 1);
1127 continue;
1128 }
cc44c765 1129 if (!prefixcmp(arg, "--disable=")) {
d819e4e6
JH
1130 enable_service(arg + 10, 0);
1131 continue;
1132 }
cc44c765 1133 if (!prefixcmp(arg, "--allow-override=")) {
74c0cc21 1134 make_service_overridable(arg + 17, 1);
d819e4e6
JH
1135 continue;
1136 }
cc44c765 1137 if (!prefixcmp(arg, "--forbid-override=")) {
74c0cc21 1138 make_service_overridable(arg + 18, 0);
d819e4e6
JH
1139 continue;
1140 }
4ae95682
PA
1141 if (!strcmp(arg, "--")) {
1142 ok_paths = &argv[i+1];
1143 break;
1144 } else if (arg[0] != '-') {
1145 ok_paths = &argv[i];
1146 break;
1147 }
e64e1b79 1148
a87e8be2
LT
1149 usage(daemon_usage);
1150 }
1151
22665bba
JS
1152 if (log_syslog) {
1153 openlog("git-daemon", 0, LOG_DAEMON);
1154 set_die_routine(daemon_die);
1155 }
1156
678dac6b
TS
1157 if (inetd_mode && (group_name || user_name))
1158 die("--user and --group are incompatible with --inetd");
1159
dd467629
JL
1160 if (inetd_mode && (listen_port || listen_addr))
1161 die("--listen= and --port= are incompatible with --inetd");
1162 else if (listen_port == 0)
1163 listen_port = DEFAULT_GIT_PORT;
1164
678dac6b
TS
1165 if (group_name && !user_name)
1166 die("--group supplied without --user");
1167
1168 if (user_name) {
1169 pass = getpwnam(user_name);
1170 if (!pass)
1171 die("user not found - %s", user_name);
1172
1173 if (!group_name)
1174 gid = pass->pw_gid;
1175 else {
1176 group = getgrnam(group_name);
1177 if (!group)
1178 die("group not found - %s", group_name);
1179
1180 gid = group->gr_gid;
1181 }
1182 }
1183
ad8b4f56
ML
1184 if (strict_paths && (!ok_paths || !*ok_paths))
1185 die("option --strict-paths requires a whitelist");
1186
20632071
JS
1187 if (base_path) {
1188 struct stat st;
1189
1190 if (stat(base_path, &st) || !S_ISDIR(st.st_mode))
1191 die("base-path '%s' does not exist or "
1192 "is not a directory", base_path);
1193 }
1194
7c3693f1 1195 if (inetd_mode) {
5b276ee4
DW
1196 struct sockaddr_storage ss;
1197 struct sockaddr *peer = (struct sockaddr *)&ss;
1198 socklen_t slen = sizeof(ss);
1199
ba0012c3 1200 freopen("/dev/null", "w", stderr);
5b276ee4
DW
1201
1202 if (getpeername(0, peer, &slen))
1203 peer = NULL;
1204
1205 return execute(peer);
7c3693f1 1206 }
bce8230d 1207
a5262768
ML
1208 if (detach)
1209 daemonize();
1210 else
1211 sanitize_stdfds();
258e93a1 1212
45ed5d7f
ML
1213 if (pid_file)
1214 store_pid(pid_file);
1215
dd467629 1216 return serve(listen_addr, listen_port, pass, gid);
a87e8be2 1217}