Merge branch 'jk/index-pack-threading-races'
[git] / http-backend.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "pkt-line.h"
4 #include "object.h"
5 #include "tag.h"
6 #include "exec_cmd.h"
7 #include "run-command.h"
8 #include "string-list.h"
9 #include "url.h"
10 #include "argv-array.h"
11
12 static const char content_type[] = "Content-Type";
13 static const char content_length[] = "Content-Length";
14 static const char last_modified[] = "Last-Modified";
15 static int getanyfile = 1;
16
17 static struct string_list *query_params;
18
19 struct rpc_service {
20         const char *name;
21         const char *config_name;
22         signed enabled : 2;
23 };
24
25 static struct rpc_service rpc_service[] = {
26         { "upload-pack", "uploadpack", 1 },
27         { "receive-pack", "receivepack", -1 },
28 };
29
30 static struct string_list *get_parameters(void)
31 {
32         if (!query_params) {
33                 const char *query = getenv("QUERY_STRING");
34
35                 query_params = xcalloc(1, sizeof(*query_params));
36                 while (query && *query) {
37                         char *name = url_decode_parameter_name(&query);
38                         char *value = url_decode_parameter_value(&query);
39                         struct string_list_item *i;
40
41                         i = string_list_lookup(query_params, name);
42                         if (!i)
43                                 i = string_list_insert(query_params, name);
44                         else
45                                 free(i->util);
46                         i->util = value;
47                 }
48         }
49         return query_params;
50 }
51
52 static const char *get_parameter(const char *name)
53 {
54         struct string_list_item *i;
55         i = string_list_lookup(get_parameters(), name);
56         return i ? i->util : NULL;
57 }
58
59 __attribute__((format (printf, 2, 3)))
60 static void format_write(int fd, const char *fmt, ...)
61 {
62         static char buffer[1024];
63
64         va_list args;
65         unsigned n;
66
67         va_start(args, fmt);
68         n = vsnprintf(buffer, sizeof(buffer), fmt, args);
69         va_end(args);
70         if (n >= sizeof(buffer))
71                 die("protocol error: impossibly long line");
72
73         write_or_die(fd, buffer, n);
74 }
75
76 static void http_status(unsigned code, const char *msg)
77 {
78         format_write(1, "Status: %u %s\r\n", code, msg);
79 }
80
81 static void hdr_str(const char *name, const char *value)
82 {
83         format_write(1, "%s: %s\r\n", name, value);
84 }
85
86 static void hdr_int(const char *name, uintmax_t value)
87 {
88         format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
89 }
90
91 static void hdr_date(const char *name, unsigned long when)
92 {
93         const char *value = show_date(when, 0, DATE_RFC2822);
94         hdr_str(name, value);
95 }
96
97 static void hdr_nocache(void)
98 {
99         hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
100         hdr_str("Pragma", "no-cache");
101         hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate");
102 }
103
104 static void hdr_cache_forever(void)
105 {
106         unsigned long now = time(NULL);
107         hdr_date("Date", now);
108         hdr_date("Expires", now + 31536000);
109         hdr_str("Cache-Control", "public, max-age=31536000");
110 }
111
112 static void end_headers(void)
113 {
114         write_or_die(1, "\r\n", 2);
115 }
116
117 __attribute__((format (printf, 1, 2)))
118 static NORETURN void not_found(const char *err, ...)
119 {
120         va_list params;
121
122         http_status(404, "Not Found");
123         hdr_nocache();
124         end_headers();
125
126         va_start(params, err);
127         if (err && *err)
128                 vfprintf(stderr, err, params);
129         va_end(params);
130         exit(0);
131 }
132
133 __attribute__((format (printf, 1, 2)))
134 static NORETURN void forbidden(const char *err, ...)
135 {
136         va_list params;
137
138         http_status(403, "Forbidden");
139         hdr_nocache();
140         end_headers();
141
142         va_start(params, err);
143         if (err && *err)
144                 vfprintf(stderr, err, params);
145         va_end(params);
146         exit(0);
147 }
148
149 static void select_getanyfile(void)
150 {
151         if (!getanyfile)
152                 forbidden("Unsupported service: getanyfile");
153 }
154
155 static void send_strbuf(const char *type, struct strbuf *buf)
156 {
157         hdr_int(content_length, buf->len);
158         hdr_str(content_type, type);
159         end_headers();
160         write_or_die(1, buf->buf, buf->len);
161 }
162
163 static void send_local_file(const char *the_type, const char *name)
164 {
165         const char *p = git_path("%s", name);
166         size_t buf_alloc = 8192;
167         char *buf = xmalloc(buf_alloc);
168         int fd;
169         struct stat sb;
170
171         fd = open(p, O_RDONLY);
172         if (fd < 0)
173                 not_found("Cannot open '%s': %s", p, strerror(errno));
174         if (fstat(fd, &sb) < 0)
175                 die_errno("Cannot stat '%s'", p);
176
177         hdr_int(content_length, sb.st_size);
178         hdr_str(content_type, the_type);
179         hdr_date(last_modified, sb.st_mtime);
180         end_headers();
181
182         for (;;) {
183                 ssize_t n = xread(fd, buf, buf_alloc);
184                 if (n < 0)
185                         die_errno("Cannot read '%s'", p);
186                 if (!n)
187                         break;
188                 write_or_die(1, buf, n);
189         }
190         close(fd);
191         free(buf);
192 }
193
194 static void get_text_file(char *name)
195 {
196         select_getanyfile();
197         hdr_nocache();
198         send_local_file("text/plain", name);
199 }
200
201 static void get_loose_object(char *name)
202 {
203         select_getanyfile();
204         hdr_cache_forever();
205         send_local_file("application/x-git-loose-object", name);
206 }
207
208 static void get_pack_file(char *name)
209 {
210         select_getanyfile();
211         hdr_cache_forever();
212         send_local_file("application/x-git-packed-objects", name);
213 }
214
215 static void get_idx_file(char *name)
216 {
217         select_getanyfile();
218         hdr_cache_forever();
219         send_local_file("application/x-git-packed-objects-toc", name);
220 }
221
222 static void http_config(void)
223 {
224         int i, value = 0;
225         struct strbuf var = STRBUF_INIT;
226
227         git_config_get_bool("http.getanyfile", &getanyfile);
228
229         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
230                 struct rpc_service *svc = &rpc_service[i];
231                 strbuf_addf(&var, "http.%s", svc->config_name);
232                 if (!git_config_get_bool(var.buf, &value))
233                         svc->enabled = value;
234                 strbuf_reset(&var);
235         }
236
237         strbuf_release(&var);
238 }
239
240 static struct rpc_service *select_service(const char *name)
241 {
242         const char *svc_name;
243         struct rpc_service *svc = NULL;
244         int i;
245
246         if (!skip_prefix(name, "git-", &svc_name))
247                 forbidden("Unsupported service: '%s'", name);
248
249         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
250                 struct rpc_service *s = &rpc_service[i];
251                 if (!strcmp(s->name, svc_name)) {
252                         svc = s;
253                         break;
254                 }
255         }
256
257         if (!svc)
258                 forbidden("Unsupported service: '%s'", name);
259
260         if (svc->enabled < 0) {
261                 const char *user = getenv("REMOTE_USER");
262                 svc->enabled = (user && *user) ? 1 : 0;
263         }
264         if (!svc->enabled)
265                 forbidden("Service not enabled: '%s'", svc->name);
266         return svc;
267 }
268
269 static void inflate_request(const char *prog_name, int out)
270 {
271         git_zstream stream;
272         unsigned char in_buf[8192];
273         unsigned char out_buf[8192];
274         unsigned long cnt = 0;
275
276         memset(&stream, 0, sizeof(stream));
277         git_inflate_init_gzip_only(&stream);
278
279         while (1) {
280                 ssize_t n = xread(0, in_buf, sizeof(in_buf));
281                 if (n <= 0)
282                         die("request ended in the middle of the gzip stream");
283
284                 stream.next_in = in_buf;
285                 stream.avail_in = n;
286
287                 while (0 < stream.avail_in) {
288                         int ret;
289
290                         stream.next_out = out_buf;
291                         stream.avail_out = sizeof(out_buf);
292
293                         ret = git_inflate(&stream, Z_NO_FLUSH);
294                         if (ret != Z_OK && ret != Z_STREAM_END)
295                                 die("zlib error inflating request, result %d", ret);
296
297                         n = stream.total_out - cnt;
298                         if (write_in_full(out, out_buf, n) != n)
299                                 die("%s aborted reading request", prog_name);
300                         cnt += n;
301
302                         if (ret == Z_STREAM_END)
303                                 goto done;
304                 }
305         }
306
307 done:
308         git_inflate_end(&stream);
309         close(out);
310 }
311
312 static void run_service(const char **argv)
313 {
314         const char *encoding = getenv("HTTP_CONTENT_ENCODING");
315         const char *user = getenv("REMOTE_USER");
316         const char *host = getenv("REMOTE_ADDR");
317         struct argv_array env = ARGV_ARRAY_INIT;
318         int gzipped_request = 0;
319         struct child_process cld = CHILD_PROCESS_INIT;
320
321         if (encoding && !strcmp(encoding, "gzip"))
322                 gzipped_request = 1;
323         else if (encoding && !strcmp(encoding, "x-gzip"))
324                 gzipped_request = 1;
325
326         if (!user || !*user)
327                 user = "anonymous";
328         if (!host || !*host)
329                 host = "(none)";
330
331         if (!getenv("GIT_COMMITTER_NAME"))
332                 argv_array_pushf(&env, "GIT_COMMITTER_NAME=%s", user);
333         if (!getenv("GIT_COMMITTER_EMAIL"))
334                 argv_array_pushf(&env, "GIT_COMMITTER_EMAIL=%s@http.%s",
335                                  user, host);
336
337         cld.argv = argv;
338         cld.env = env.argv;
339         if (gzipped_request)
340                 cld.in = -1;
341         cld.git_cmd = 1;
342         if (start_command(&cld))
343                 exit(1);
344
345         close(1);
346         if (gzipped_request)
347                 inflate_request(argv[0], cld.in);
348         else
349                 close(0);
350
351         if (finish_command(&cld))
352                 exit(1);
353         argv_array_clear(&env);
354 }
355
356 static int show_text_ref(const char *name, const unsigned char *sha1,
357         int flag, void *cb_data)
358 {
359         const char *name_nons = strip_namespace(name);
360         struct strbuf *buf = cb_data;
361         struct object *o = parse_object(sha1);
362         if (!o)
363                 return 0;
364
365         strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name_nons);
366         if (o->type == OBJ_TAG) {
367                 o = deref_tag(o, name, 0);
368                 if (!o)
369                         return 0;
370                 strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1),
371                             name_nons);
372         }
373         return 0;
374 }
375
376 static void get_info_refs(char *arg)
377 {
378         const char *service_name = get_parameter("service");
379         struct strbuf buf = STRBUF_INIT;
380
381         hdr_nocache();
382
383         if (service_name) {
384                 const char *argv[] = {NULL /* service name */,
385                         "--stateless-rpc", "--advertise-refs",
386                         ".", NULL};
387                 struct rpc_service *svc = select_service(service_name);
388
389                 strbuf_addf(&buf, "application/x-git-%s-advertisement",
390                         svc->name);
391                 hdr_str(content_type, buf.buf);
392                 end_headers();
393
394                 packet_write(1, "# service=git-%s\n", svc->name);
395                 packet_flush(1);
396
397                 argv[0] = svc->name;
398                 run_service(argv);
399
400         } else {
401                 select_getanyfile();
402                 for_each_namespaced_ref(show_text_ref, &buf);
403                 send_strbuf("text/plain", &buf);
404         }
405         strbuf_release(&buf);
406 }
407
408 static int show_head_ref(const char *refname, const unsigned char *sha1,
409         int flag, void *cb_data)
410 {
411         struct strbuf *buf = cb_data;
412
413         if (flag & REF_ISSYMREF) {
414                 unsigned char unused[20];
415                 const char *target = resolve_ref_unsafe(refname, unused, 1, NULL);
416                 const char *target_nons = strip_namespace(target);
417
418                 strbuf_addf(buf, "ref: %s\n", target_nons);
419         } else {
420                 strbuf_addf(buf, "%s\n", sha1_to_hex(sha1));
421         }
422
423         return 0;
424 }
425
426 static void get_head(char *arg)
427 {
428         struct strbuf buf = STRBUF_INIT;
429
430         select_getanyfile();
431         head_ref_namespaced(show_head_ref, &buf);
432         send_strbuf("text/plain", &buf);
433         strbuf_release(&buf);
434 }
435
436 static void get_info_packs(char *arg)
437 {
438         size_t objdirlen = strlen(get_object_directory());
439         struct strbuf buf = STRBUF_INIT;
440         struct packed_git *p;
441         size_t cnt = 0;
442
443         select_getanyfile();
444         prepare_packed_git();
445         for (p = packed_git; p; p = p->next) {
446                 if (p->pack_local)
447                         cnt++;
448         }
449
450         strbuf_grow(&buf, cnt * 53 + 2);
451         for (p = packed_git; p; p = p->next) {
452                 if (p->pack_local)
453                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
454         }
455         strbuf_addch(&buf, '\n');
456
457         hdr_nocache();
458         send_strbuf("text/plain; charset=utf-8", &buf);
459         strbuf_release(&buf);
460 }
461
462 static void check_content_type(const char *accepted_type)
463 {
464         const char *actual_type = getenv("CONTENT_TYPE");
465
466         if (!actual_type)
467                 actual_type = "";
468
469         if (strcmp(actual_type, accepted_type)) {
470                 http_status(415, "Unsupported Media Type");
471                 hdr_nocache();
472                 end_headers();
473                 format_write(1,
474                         "Expected POST with Content-Type '%s',"
475                         " but received '%s' instead.\n",
476                         accepted_type, actual_type);
477                 exit(0);
478         }
479 }
480
481 static void service_rpc(char *service_name)
482 {
483         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
484         struct rpc_service *svc = select_service(service_name);
485         struct strbuf buf = STRBUF_INIT;
486
487         strbuf_reset(&buf);
488         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
489         check_content_type(buf.buf);
490
491         hdr_nocache();
492
493         strbuf_reset(&buf);
494         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
495         hdr_str(content_type, buf.buf);
496
497         end_headers();
498
499         argv[0] = svc->name;
500         run_service(argv);
501         strbuf_release(&buf);
502 }
503
504 static NORETURN void die_webcgi(const char *err, va_list params)
505 {
506         static int dead;
507
508         if (!dead) {
509                 dead = 1;
510                 http_status(500, "Internal Server Error");
511                 hdr_nocache();
512                 end_headers();
513
514                 vreportf("fatal: ", err, params);
515         }
516         exit(0); /* we successfully reported a failure ;-) */
517 }
518
519 static char* getdir(void)
520 {
521         struct strbuf buf = STRBUF_INIT;
522         char *pathinfo = getenv("PATH_INFO");
523         char *root = getenv("GIT_PROJECT_ROOT");
524         char *path = getenv("PATH_TRANSLATED");
525
526         if (root && *root) {
527                 if (!pathinfo || !*pathinfo)
528                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
529                 if (daemon_avoid_alias(pathinfo))
530                         die("'%s': aliased", pathinfo);
531                 end_url_with_slash(&buf, root);
532                 if (pathinfo[0] == '/')
533                         pathinfo++;
534                 strbuf_addstr(&buf, pathinfo);
535                 return strbuf_detach(&buf, NULL);
536         } else if (path && *path) {
537                 return xstrdup(path);
538         } else
539                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
540         return NULL;
541 }
542
543 static struct service_cmd {
544         const char *method;
545         const char *pattern;
546         void (*imp)(char *);
547 } services[] = {
548         {"GET", "/HEAD$", get_head},
549         {"GET", "/info/refs$", get_info_refs},
550         {"GET", "/objects/info/alternates$", get_text_file},
551         {"GET", "/objects/info/http-alternates$", get_text_file},
552         {"GET", "/objects/info/packs$", get_info_packs},
553         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
554         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
555         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
556
557         {"POST", "/git-upload-pack$", service_rpc},
558         {"POST", "/git-receive-pack$", service_rpc}
559 };
560
561 int main(int argc, char **argv)
562 {
563         char *method = getenv("REQUEST_METHOD");
564         char *dir;
565         struct service_cmd *cmd = NULL;
566         char *cmd_arg = NULL;
567         int i;
568
569         git_setup_gettext();
570
571         git_extract_argv0_path(argv[0]);
572         set_die_routine(die_webcgi);
573
574         if (!method)
575                 die("No REQUEST_METHOD from server");
576         if (!strcmp(method, "HEAD"))
577                 method = "GET";
578         dir = getdir();
579
580         for (i = 0; i < ARRAY_SIZE(services); i++) {
581                 struct service_cmd *c = &services[i];
582                 regex_t re;
583                 regmatch_t out[1];
584
585                 if (regcomp(&re, c->pattern, REG_EXTENDED))
586                         die("Bogus regex in service table: %s", c->pattern);
587                 if (!regexec(&re, dir, 1, out, 0)) {
588                         size_t n;
589
590                         if (strcmp(method, c->method)) {
591                                 const char *proto = getenv("SERVER_PROTOCOL");
592                                 if (proto && !strcmp(proto, "HTTP/1.1")) {
593                                         http_status(405, "Method Not Allowed");
594                                         hdr_str("Allow", !strcmp(c->method, "GET") ?
595                                                 "GET, HEAD" : c->method);
596                                 } else
597                                         http_status(400, "Bad Request");
598                                 hdr_nocache();
599                                 end_headers();
600                                 return 0;
601                         }
602
603                         cmd = c;
604                         n = out[0].rm_eo - out[0].rm_so;
605                         cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
606                         dir[out[0].rm_so] = 0;
607                         break;
608                 }
609                 regfree(&re);
610         }
611
612         if (!cmd)
613                 not_found("Request not supported: '%s'", dir);
614
615         setup_path();
616         if (!enter_repo(dir, 0))
617                 not_found("Not a git repository: '%s'", dir);
618         if (!getenv("GIT_HTTP_EXPORT_ALL") &&
619             access("git-daemon-export-ok", F_OK) )
620                 not_found("Repository not exported: '%s'", dir);
621
622         http_config();
623         cmd->imp(cmd_arg);
624         return 0;
625 }