Merge branch 'sb/prepare-revision-walk-error-check'
[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 int http_config(const char *var, const char *value, void *cb)
223 {
224         const char *p;
225
226         if (!strcmp(var, "http.getanyfile")) {
227                 getanyfile = git_config_bool(var, value);
228                 return 0;
229         }
230
231         if (skip_prefix(var, "http.", &p)) {
232                 int i;
233
234                 for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
235                         struct rpc_service *svc = &rpc_service[i];
236                         if (!strcmp(p, svc->config_name)) {
237                                 svc->enabled = git_config_bool(var, value);
238                                 return 0;
239                         }
240                 }
241         }
242
243         /* we are not interested in parsing any other configuration here */
244         return 0;
245 }
246
247 static struct rpc_service *select_service(const char *name)
248 {
249         const char *svc_name;
250         struct rpc_service *svc = NULL;
251         int i;
252
253         if (!skip_prefix(name, "git-", &svc_name))
254                 forbidden("Unsupported service: '%s'", name);
255
256         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
257                 struct rpc_service *s = &rpc_service[i];
258                 if (!strcmp(s->name, svc_name)) {
259                         svc = s;
260                         break;
261                 }
262         }
263
264         if (!svc)
265                 forbidden("Unsupported service: '%s'", name);
266
267         if (svc->enabled < 0) {
268                 const char *user = getenv("REMOTE_USER");
269                 svc->enabled = (user && *user) ? 1 : 0;
270         }
271         if (!svc->enabled)
272                 forbidden("Service not enabled: '%s'", svc->name);
273         return svc;
274 }
275
276 static void inflate_request(const char *prog_name, int out)
277 {
278         git_zstream stream;
279         unsigned char in_buf[8192];
280         unsigned char out_buf[8192];
281         unsigned long cnt = 0;
282
283         memset(&stream, 0, sizeof(stream));
284         git_inflate_init_gzip_only(&stream);
285
286         while (1) {
287                 ssize_t n = xread(0, in_buf, sizeof(in_buf));
288                 if (n <= 0)
289                         die("request ended in the middle of the gzip stream");
290
291                 stream.next_in = in_buf;
292                 stream.avail_in = n;
293
294                 while (0 < stream.avail_in) {
295                         int ret;
296
297                         stream.next_out = out_buf;
298                         stream.avail_out = sizeof(out_buf);
299
300                         ret = git_inflate(&stream, Z_NO_FLUSH);
301                         if (ret != Z_OK && ret != Z_STREAM_END)
302                                 die("zlib error inflating request, result %d", ret);
303
304                         n = stream.total_out - cnt;
305                         if (write_in_full(out, out_buf, n) != n)
306                                 die("%s aborted reading request", prog_name);
307                         cnt += n;
308
309                         if (ret == Z_STREAM_END)
310                                 goto done;
311                 }
312         }
313
314 done:
315         git_inflate_end(&stream);
316         close(out);
317 }
318
319 static void run_service(const char **argv)
320 {
321         const char *encoding = getenv("HTTP_CONTENT_ENCODING");
322         const char *user = getenv("REMOTE_USER");
323         const char *host = getenv("REMOTE_ADDR");
324         struct argv_array env = ARGV_ARRAY_INIT;
325         int gzipped_request = 0;
326         struct child_process cld;
327
328         if (encoding && !strcmp(encoding, "gzip"))
329                 gzipped_request = 1;
330         else if (encoding && !strcmp(encoding, "x-gzip"))
331                 gzipped_request = 1;
332
333         if (!user || !*user)
334                 user = "anonymous";
335         if (!host || !*host)
336                 host = "(none)";
337
338         if (!getenv("GIT_COMMITTER_NAME"))
339                 argv_array_pushf(&env, "GIT_COMMITTER_NAME=%s", user);
340         if (!getenv("GIT_COMMITTER_EMAIL"))
341                 argv_array_pushf(&env, "GIT_COMMITTER_EMAIL=%s@http.%s",
342                                  user, host);
343
344         memset(&cld, 0, sizeof(cld));
345         cld.argv = argv;
346         cld.env = env.argv;
347         if (gzipped_request)
348                 cld.in = -1;
349         cld.git_cmd = 1;
350         if (start_command(&cld))
351                 exit(1);
352
353         close(1);
354         if (gzipped_request)
355                 inflate_request(argv[0], cld.in);
356         else
357                 close(0);
358
359         if (finish_command(&cld))
360                 exit(1);
361         argv_array_clear(&env);
362 }
363
364 static int show_text_ref(const char *name, const unsigned char *sha1,
365         int flag, void *cb_data)
366 {
367         const char *name_nons = strip_namespace(name);
368         struct strbuf *buf = cb_data;
369         struct object *o = parse_object(sha1);
370         if (!o)
371                 return 0;
372
373         strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name_nons);
374         if (o->type == OBJ_TAG) {
375                 o = deref_tag(o, name, 0);
376                 if (!o)
377                         return 0;
378                 strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1),
379                             name_nons);
380         }
381         return 0;
382 }
383
384 static void get_info_refs(char *arg)
385 {
386         const char *service_name = get_parameter("service");
387         struct strbuf buf = STRBUF_INIT;
388
389         hdr_nocache();
390
391         if (service_name) {
392                 const char *argv[] = {NULL /* service name */,
393                         "--stateless-rpc", "--advertise-refs",
394                         ".", NULL};
395                 struct rpc_service *svc = select_service(service_name);
396
397                 strbuf_addf(&buf, "application/x-git-%s-advertisement",
398                         svc->name);
399                 hdr_str(content_type, buf.buf);
400                 end_headers();
401
402                 packet_write(1, "# service=git-%s\n", svc->name);
403                 packet_flush(1);
404
405                 argv[0] = svc->name;
406                 run_service(argv);
407
408         } else {
409                 select_getanyfile();
410                 for_each_namespaced_ref(show_text_ref, &buf);
411                 send_strbuf("text/plain", &buf);
412         }
413         strbuf_release(&buf);
414 }
415
416 static int show_head_ref(const char *refname, const unsigned char *sha1,
417         int flag, void *cb_data)
418 {
419         struct strbuf *buf = cb_data;
420
421         if (flag & REF_ISSYMREF) {
422                 unsigned char unused[20];
423                 const char *target = resolve_ref_unsafe(refname, unused, 1, NULL);
424                 const char *target_nons = strip_namespace(target);
425
426                 strbuf_addf(buf, "ref: %s\n", target_nons);
427         } else {
428                 strbuf_addf(buf, "%s\n", sha1_to_hex(sha1));
429         }
430
431         return 0;
432 }
433
434 static void get_head(char *arg)
435 {
436         struct strbuf buf = STRBUF_INIT;
437
438         select_getanyfile();
439         head_ref_namespaced(show_head_ref, &buf);
440         send_strbuf("text/plain", &buf);
441         strbuf_release(&buf);
442 }
443
444 static void get_info_packs(char *arg)
445 {
446         size_t objdirlen = strlen(get_object_directory());
447         struct strbuf buf = STRBUF_INIT;
448         struct packed_git *p;
449         size_t cnt = 0;
450
451         select_getanyfile();
452         prepare_packed_git();
453         for (p = packed_git; p; p = p->next) {
454                 if (p->pack_local)
455                         cnt++;
456         }
457
458         strbuf_grow(&buf, cnt * 53 + 2);
459         for (p = packed_git; p; p = p->next) {
460                 if (p->pack_local)
461                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
462         }
463         strbuf_addch(&buf, '\n');
464
465         hdr_nocache();
466         send_strbuf("text/plain; charset=utf-8", &buf);
467         strbuf_release(&buf);
468 }
469
470 static void check_content_type(const char *accepted_type)
471 {
472         const char *actual_type = getenv("CONTENT_TYPE");
473
474         if (!actual_type)
475                 actual_type = "";
476
477         if (strcmp(actual_type, accepted_type)) {
478                 http_status(415, "Unsupported Media Type");
479                 hdr_nocache();
480                 end_headers();
481                 format_write(1,
482                         "Expected POST with Content-Type '%s',"
483                         " but received '%s' instead.\n",
484                         accepted_type, actual_type);
485                 exit(0);
486         }
487 }
488
489 static void service_rpc(char *service_name)
490 {
491         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
492         struct rpc_service *svc = select_service(service_name);
493         struct strbuf buf = STRBUF_INIT;
494
495         strbuf_reset(&buf);
496         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
497         check_content_type(buf.buf);
498
499         hdr_nocache();
500
501         strbuf_reset(&buf);
502         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
503         hdr_str(content_type, buf.buf);
504
505         end_headers();
506
507         argv[0] = svc->name;
508         run_service(argv);
509         strbuf_release(&buf);
510 }
511
512 static NORETURN void die_webcgi(const char *err, va_list params)
513 {
514         static int dead;
515
516         if (!dead) {
517                 dead = 1;
518                 http_status(500, "Internal Server Error");
519                 hdr_nocache();
520                 end_headers();
521
522                 vreportf("fatal: ", err, params);
523         }
524         exit(0); /* we successfully reported a failure ;-) */
525 }
526
527 static char* getdir(void)
528 {
529         struct strbuf buf = STRBUF_INIT;
530         char *pathinfo = getenv("PATH_INFO");
531         char *root = getenv("GIT_PROJECT_ROOT");
532         char *path = getenv("PATH_TRANSLATED");
533
534         if (root && *root) {
535                 if (!pathinfo || !*pathinfo)
536                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
537                 if (daemon_avoid_alias(pathinfo))
538                         die("'%s': aliased", pathinfo);
539                 end_url_with_slash(&buf, root);
540                 if (pathinfo[0] == '/')
541                         pathinfo++;
542                 strbuf_addstr(&buf, pathinfo);
543                 return strbuf_detach(&buf, NULL);
544         } else if (path && *path) {
545                 return xstrdup(path);
546         } else
547                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
548         return NULL;
549 }
550
551 static struct service_cmd {
552         const char *method;
553         const char *pattern;
554         void (*imp)(char *);
555 } services[] = {
556         {"GET", "/HEAD$", get_head},
557         {"GET", "/info/refs$", get_info_refs},
558         {"GET", "/objects/info/alternates$", get_text_file},
559         {"GET", "/objects/info/http-alternates$", get_text_file},
560         {"GET", "/objects/info/packs$", get_info_packs},
561         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
562         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
563         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
564
565         {"POST", "/git-upload-pack$", service_rpc},
566         {"POST", "/git-receive-pack$", service_rpc}
567 };
568
569 int main(int argc, char **argv)
570 {
571         char *method = getenv("REQUEST_METHOD");
572         char *dir;
573         struct service_cmd *cmd = NULL;
574         char *cmd_arg = NULL;
575         int i;
576
577         git_setup_gettext();
578
579         git_extract_argv0_path(argv[0]);
580         set_die_routine(die_webcgi);
581
582         if (!method)
583                 die("No REQUEST_METHOD from server");
584         if (!strcmp(method, "HEAD"))
585                 method = "GET";
586         dir = getdir();
587
588         for (i = 0; i < ARRAY_SIZE(services); i++) {
589                 struct service_cmd *c = &services[i];
590                 regex_t re;
591                 regmatch_t out[1];
592
593                 if (regcomp(&re, c->pattern, REG_EXTENDED))
594                         die("Bogus regex in service table: %s", c->pattern);
595                 if (!regexec(&re, dir, 1, out, 0)) {
596                         size_t n;
597
598                         if (strcmp(method, c->method)) {
599                                 const char *proto = getenv("SERVER_PROTOCOL");
600                                 if (proto && !strcmp(proto, "HTTP/1.1")) {
601                                         http_status(405, "Method Not Allowed");
602                                         hdr_str("Allow", !strcmp(c->method, "GET") ?
603                                                 "GET, HEAD" : c->method);
604                                 } else
605                                         http_status(400, "Bad Request");
606                                 hdr_nocache();
607                                 end_headers();
608                                 return 0;
609                         }
610
611                         cmd = c;
612                         n = out[0].rm_eo - out[0].rm_so;
613                         cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
614                         dir[out[0].rm_so] = 0;
615                         break;
616                 }
617                 regfree(&re);
618         }
619
620         if (!cmd)
621                 not_found("Request not supported: '%s'", dir);
622
623         setup_path();
624         if (!enter_repo(dir, 0))
625                 not_found("Not a git repository: '%s'", dir);
626         if (!getenv("GIT_HTTP_EXPORT_ALL") &&
627             access("git-daemon-export-ok", F_OK) )
628                 not_found("Repository not exported: '%s'", dir);
629
630         git_config(http_config, NULL);
631         cmd->imp(cmd_arg);
632         return 0;
633 }