Merge branch 'nd/root-git'
[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
10 static const char content_type[] = "Content-Type";
11 static const char content_length[] = "Content-Length";
12 static const char last_modified[] = "Last-Modified";
13 static int getanyfile = 1;
14
15 static struct string_list *query_params;
16
17 struct rpc_service {
18         const char *name;
19         const char *config_name;
20         signed enabled : 2;
21 };
22
23 static struct rpc_service rpc_service[] = {
24         { "upload-pack", "uploadpack", 1 },
25         { "receive-pack", "receivepack", -1 },
26 };
27
28 static int decode_char(const char *q)
29 {
30         int i;
31         unsigned char val = 0;
32         for (i = 0; i < 2; i++) {
33                 unsigned char c = *q++;
34                 val <<= 4;
35                 if (c >= '0' && c <= '9')
36                         val += c - '0';
37                 else if (c >= 'a' && c <= 'f')
38                         val += c - 'a' + 10;
39                 else if (c >= 'A' && c <= 'F')
40                         val += c - 'A' + 10;
41                 else
42                         return -1;
43         }
44         return val;
45 }
46
47 static char *decode_parameter(const char **query, int is_name)
48 {
49         const char *q = *query;
50         struct strbuf out;
51
52         strbuf_init(&out, 16);
53         do {
54                 unsigned char c = *q;
55
56                 if (!c)
57                         break;
58                 if (c == '&' || (is_name && c == '=')) {
59                         q++;
60                         break;
61                 }
62
63                 if (c == '%') {
64                         int val = decode_char(q + 1);
65                         if (0 <= val) {
66                                 strbuf_addch(&out, val);
67                                 q += 3;
68                                 continue;
69                         }
70                 }
71
72                 if (c == '+')
73                         strbuf_addch(&out, ' ');
74                 else
75                         strbuf_addch(&out, c);
76                 q++;
77         } while (1);
78         *query = q;
79         return strbuf_detach(&out, NULL);
80 }
81
82 static struct string_list *get_parameters(void)
83 {
84         if (!query_params) {
85                 const char *query = getenv("QUERY_STRING");
86
87                 query_params = xcalloc(1, sizeof(*query_params));
88                 while (query && *query) {
89                         char *name = decode_parameter(&query, 1);
90                         char *value = decode_parameter(&query, 0);
91                         struct string_list_item *i;
92
93                         i = string_list_lookup(name, query_params);
94                         if (!i)
95                                 i = string_list_insert(name, query_params);
96                         else
97                                 free(i->util);
98                         i->util = value;
99                 }
100         }
101         return query_params;
102 }
103
104 static const char *get_parameter(const char *name)
105 {
106         struct string_list_item *i;
107         i = string_list_lookup(name, get_parameters());
108         return i ? i->util : NULL;
109 }
110
111 __attribute__((format (printf, 2, 3)))
112 static void format_write(int fd, const char *fmt, ...)
113 {
114         static char buffer[1024];
115
116         va_list args;
117         unsigned n;
118
119         va_start(args, fmt);
120         n = vsnprintf(buffer, sizeof(buffer), fmt, args);
121         va_end(args);
122         if (n >= sizeof(buffer))
123                 die("protocol error: impossibly long line");
124
125         safe_write(fd, buffer, n);
126 }
127
128 static void http_status(unsigned code, const char *msg)
129 {
130         format_write(1, "Status: %u %s\r\n", code, msg);
131 }
132
133 static void hdr_str(const char *name, const char *value)
134 {
135         format_write(1, "%s: %s\r\n", name, value);
136 }
137
138 static void hdr_int(const char *name, uintmax_t value)
139 {
140         format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
141 }
142
143 static void hdr_date(const char *name, unsigned long when)
144 {
145         const char *value = show_date(when, 0, DATE_RFC2822);
146         hdr_str(name, value);
147 }
148
149 static void hdr_nocache(void)
150 {
151         hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
152         hdr_str("Pragma", "no-cache");
153         hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate");
154 }
155
156 static void hdr_cache_forever(void)
157 {
158         unsigned long now = time(NULL);
159         hdr_date("Date", now);
160         hdr_date("Expires", now + 31536000);
161         hdr_str("Cache-Control", "public, max-age=31536000");
162 }
163
164 static void end_headers(void)
165 {
166         safe_write(1, "\r\n", 2);
167 }
168
169 __attribute__((format (printf, 1, 2)))
170 static NORETURN void not_found(const char *err, ...)
171 {
172         va_list params;
173
174         http_status(404, "Not Found");
175         hdr_nocache();
176         end_headers();
177
178         va_start(params, err);
179         if (err && *err)
180                 vfprintf(stderr, err, params);
181         va_end(params);
182         exit(0);
183 }
184
185 __attribute__((format (printf, 1, 2)))
186 static NORETURN void forbidden(const char *err, ...)
187 {
188         va_list params;
189
190         http_status(403, "Forbidden");
191         hdr_nocache();
192         end_headers();
193
194         va_start(params, err);
195         if (err && *err)
196                 vfprintf(stderr, err, params);
197         va_end(params);
198         exit(0);
199 }
200
201 static void select_getanyfile(void)
202 {
203         if (!getanyfile)
204                 forbidden("Unsupported service: getanyfile");
205 }
206
207 static void send_strbuf(const char *type, struct strbuf *buf)
208 {
209         hdr_int(content_length, buf->len);
210         hdr_str(content_type, type);
211         end_headers();
212         safe_write(1, buf->buf, buf->len);
213 }
214
215 static void send_local_file(const char *the_type, const char *name)
216 {
217         const char *p = git_path("%s", name);
218         size_t buf_alloc = 8192;
219         char *buf = xmalloc(buf_alloc);
220         int fd;
221         struct stat sb;
222
223         fd = open(p, O_RDONLY);
224         if (fd < 0)
225                 not_found("Cannot open '%s': %s", p, strerror(errno));
226         if (fstat(fd, &sb) < 0)
227                 die_errno("Cannot stat '%s'", p);
228
229         hdr_int(content_length, sb.st_size);
230         hdr_str(content_type, the_type);
231         hdr_date(last_modified, sb.st_mtime);
232         end_headers();
233
234         for (;;) {
235                 ssize_t n = xread(fd, buf, buf_alloc);
236                 if (n < 0)
237                         die_errno("Cannot read '%s'", p);
238                 if (!n)
239                         break;
240                 safe_write(1, buf, n);
241         }
242         close(fd);
243         free(buf);
244 }
245
246 static void get_text_file(char *name)
247 {
248         select_getanyfile();
249         hdr_nocache();
250         send_local_file("text/plain", name);
251 }
252
253 static void get_loose_object(char *name)
254 {
255         select_getanyfile();
256         hdr_cache_forever();
257         send_local_file("application/x-git-loose-object", name);
258 }
259
260 static void get_pack_file(char *name)
261 {
262         select_getanyfile();
263         hdr_cache_forever();
264         send_local_file("application/x-git-packed-objects", name);
265 }
266
267 static void get_idx_file(char *name)
268 {
269         select_getanyfile();
270         hdr_cache_forever();
271         send_local_file("application/x-git-packed-objects-toc", name);
272 }
273
274 static int http_config(const char *var, const char *value, void *cb)
275 {
276         if (!strcmp(var, "http.getanyfile")) {
277                 getanyfile = git_config_bool(var, value);
278                 return 0;
279         }
280
281         if (!prefixcmp(var, "http.")) {
282                 int i;
283
284                 for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
285                         struct rpc_service *svc = &rpc_service[i];
286                         if (!strcmp(var + 5, svc->config_name)) {
287                                 svc->enabled = git_config_bool(var, value);
288                                 return 0;
289                         }
290                 }
291         }
292
293         /* we are not interested in parsing any other configuration here */
294         return 0;
295 }
296
297 static struct rpc_service *select_service(const char *name)
298 {
299         struct rpc_service *svc = NULL;
300         int i;
301
302         if (prefixcmp(name, "git-"))
303                 forbidden("Unsupported service: '%s'", name);
304
305         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
306                 struct rpc_service *s = &rpc_service[i];
307                 if (!strcmp(s->name, name + 4)) {
308                         svc = s;
309                         break;
310                 }
311         }
312
313         if (!svc)
314                 forbidden("Unsupported service: '%s'", name);
315
316         if (svc->enabled < 0) {
317                 const char *user = getenv("REMOTE_USER");
318                 svc->enabled = (user && *user) ? 1 : 0;
319         }
320         if (!svc->enabled)
321                 forbidden("Service not enabled: '%s'", svc->name);
322         return svc;
323 }
324
325 static void inflate_request(const char *prog_name, int out)
326 {
327         z_stream stream;
328         unsigned char in_buf[8192];
329         unsigned char out_buf[8192];
330         unsigned long cnt = 0;
331         int ret;
332
333         memset(&stream, 0, sizeof(stream));
334         ret = inflateInit2(&stream, (15 + 16));
335         if (ret != Z_OK)
336                 die("cannot start zlib inflater, zlib err %d", ret);
337
338         while (1) {
339                 ssize_t n = xread(0, in_buf, sizeof(in_buf));
340                 if (n <= 0)
341                         die("request ended in the middle of the gzip stream");
342
343                 stream.next_in = in_buf;
344                 stream.avail_in = n;
345
346                 while (0 < stream.avail_in) {
347                         int ret;
348
349                         stream.next_out = out_buf;
350                         stream.avail_out = sizeof(out_buf);
351
352                         ret = inflate(&stream, Z_NO_FLUSH);
353                         if (ret != Z_OK && ret != Z_STREAM_END)
354                                 die("zlib error inflating request, result %d", ret);
355
356                         n = stream.total_out - cnt;
357                         if (write_in_full(out, out_buf, n) != n)
358                                 die("%s aborted reading request", prog_name);
359                         cnt += n;
360
361                         if (ret == Z_STREAM_END)
362                                 goto done;
363                 }
364         }
365
366 done:
367         inflateEnd(&stream);
368         close(out);
369 }
370
371 static void run_service(const char **argv)
372 {
373         const char *encoding = getenv("HTTP_CONTENT_ENCODING");
374         const char *user = getenv("REMOTE_USER");
375         const char *host = getenv("REMOTE_ADDR");
376         char *env[3];
377         struct strbuf buf = STRBUF_INIT;
378         int gzipped_request = 0;
379         struct child_process cld;
380
381         if (encoding && !strcmp(encoding, "gzip"))
382                 gzipped_request = 1;
383         else if (encoding && !strcmp(encoding, "x-gzip"))
384                 gzipped_request = 1;
385
386         if (!user || !*user)
387                 user = "anonymous";
388         if (!host || !*host)
389                 host = "(none)";
390
391         memset(&env, 0, sizeof(env));
392         strbuf_addf(&buf, "GIT_COMMITTER_NAME=%s", user);
393         env[0] = strbuf_detach(&buf, NULL);
394
395         strbuf_addf(&buf, "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
396         env[1] = strbuf_detach(&buf, NULL);
397         env[2] = NULL;
398
399         memset(&cld, 0, sizeof(cld));
400         cld.argv = argv;
401         cld.env = (const char *const *)env;
402         if (gzipped_request)
403                 cld.in = -1;
404         cld.git_cmd = 1;
405         if (start_command(&cld))
406                 exit(1);
407
408         close(1);
409         if (gzipped_request)
410                 inflate_request(argv[0], cld.in);
411         else
412                 close(0);
413
414         if (finish_command(&cld))
415                 exit(1);
416         free(env[0]);
417         free(env[1]);
418         strbuf_release(&buf);
419 }
420
421 static int show_text_ref(const char *name, const unsigned char *sha1,
422         int flag, void *cb_data)
423 {
424         struct strbuf *buf = cb_data;
425         struct object *o = parse_object(sha1);
426         if (!o)
427                 return 0;
428
429         strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name);
430         if (o->type == OBJ_TAG) {
431                 o = deref_tag(o, name, 0);
432                 if (!o)
433                         return 0;
434                 strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1), name);
435         }
436         return 0;
437 }
438
439 static void get_info_refs(char *arg)
440 {
441         const char *service_name = get_parameter("service");
442         struct strbuf buf = STRBUF_INIT;
443
444         hdr_nocache();
445
446         if (service_name) {
447                 const char *argv[] = {NULL /* service name */,
448                         "--stateless-rpc", "--advertise-refs",
449                         ".", NULL};
450                 struct rpc_service *svc = select_service(service_name);
451
452                 strbuf_addf(&buf, "application/x-git-%s-advertisement",
453                         svc->name);
454                 hdr_str(content_type, buf.buf);
455                 end_headers();
456
457                 packet_write(1, "# service=git-%s\n", svc->name);
458                 packet_flush(1);
459
460                 argv[0] = svc->name;
461                 run_service(argv);
462
463         } else {
464                 select_getanyfile();
465                 for_each_ref(show_text_ref, &buf);
466                 send_strbuf("text/plain", &buf);
467         }
468         strbuf_release(&buf);
469 }
470
471 static void get_info_packs(char *arg)
472 {
473         size_t objdirlen = strlen(get_object_directory());
474         struct strbuf buf = STRBUF_INIT;
475         struct packed_git *p;
476         size_t cnt = 0;
477
478         select_getanyfile();
479         prepare_packed_git();
480         for (p = packed_git; p; p = p->next) {
481                 if (p->pack_local)
482                         cnt++;
483         }
484
485         strbuf_grow(&buf, cnt * 53 + 2);
486         for (p = packed_git; p; p = p->next) {
487                 if (p->pack_local)
488                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
489         }
490         strbuf_addch(&buf, '\n');
491
492         hdr_nocache();
493         send_strbuf("text/plain; charset=utf-8", &buf);
494         strbuf_release(&buf);
495 }
496
497 static void check_content_type(const char *accepted_type)
498 {
499         const char *actual_type = getenv("CONTENT_TYPE");
500
501         if (!actual_type)
502                 actual_type = "";
503
504         if (strcmp(actual_type, accepted_type)) {
505                 http_status(415, "Unsupported Media Type");
506                 hdr_nocache();
507                 end_headers();
508                 format_write(1,
509                         "Expected POST with Content-Type '%s',"
510                         " but received '%s' instead.\n",
511                         accepted_type, actual_type);
512                 exit(0);
513         }
514 }
515
516 static void service_rpc(char *service_name)
517 {
518         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
519         struct rpc_service *svc = select_service(service_name);
520         struct strbuf buf = STRBUF_INIT;
521
522         strbuf_reset(&buf);
523         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
524         check_content_type(buf.buf);
525
526         hdr_nocache();
527
528         strbuf_reset(&buf);
529         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
530         hdr_str(content_type, buf.buf);
531
532         end_headers();
533
534         argv[0] = svc->name;
535         run_service(argv);
536         strbuf_release(&buf);
537 }
538
539 static NORETURN void die_webcgi(const char *err, va_list params)
540 {
541         char buffer[1000];
542
543         http_status(500, "Internal Server Error");
544         hdr_nocache();
545         end_headers();
546
547         vsnprintf(buffer, sizeof(buffer), err, params);
548         fprintf(stderr, "fatal: %s\n", buffer);
549         exit(0);
550 }
551
552 static char* getdir(void)
553 {
554         struct strbuf buf = STRBUF_INIT;
555         char *pathinfo = getenv("PATH_INFO");
556         char *root = getenv("GIT_PROJECT_ROOT");
557         char *path = getenv("PATH_TRANSLATED");
558
559         if (root && *root) {
560                 if (!pathinfo || !*pathinfo)
561                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
562                 if (daemon_avoid_alias(pathinfo))
563                         die("'%s': aliased", pathinfo);
564                 strbuf_addstr(&buf, root);
565                 if (buf.buf[buf.len - 1] != '/')
566                         strbuf_addch(&buf, '/');
567                 if (pathinfo[0] == '/')
568                         pathinfo++;
569                 strbuf_addstr(&buf, pathinfo);
570                 return strbuf_detach(&buf, NULL);
571         } else if (path && *path) {
572                 return xstrdup(path);
573         } else
574                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
575         return NULL;
576 }
577
578 static struct service_cmd {
579         const char *method;
580         const char *pattern;
581         void (*imp)(char *);
582 } services[] = {
583         {"GET", "/HEAD$", get_text_file},
584         {"GET", "/info/refs$", get_info_refs},
585         {"GET", "/objects/info/alternates$", get_text_file},
586         {"GET", "/objects/info/http-alternates$", get_text_file},
587         {"GET", "/objects/info/packs$", get_info_packs},
588         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
589         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
590         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
591
592         {"POST", "/git-upload-pack$", service_rpc},
593         {"POST", "/git-receive-pack$", service_rpc}
594 };
595
596 int main(int argc, char **argv)
597 {
598         char *method = getenv("REQUEST_METHOD");
599         char *dir;
600         struct service_cmd *cmd = NULL;
601         char *cmd_arg = NULL;
602         int i;
603
604         git_extract_argv0_path(argv[0]);
605         set_die_routine(die_webcgi);
606
607         if (!method)
608                 die("No REQUEST_METHOD from server");
609         if (!strcmp(method, "HEAD"))
610                 method = "GET";
611         dir = getdir();
612
613         for (i = 0; i < ARRAY_SIZE(services); i++) {
614                 struct service_cmd *c = &services[i];
615                 regex_t re;
616                 regmatch_t out[1];
617
618                 if (regcomp(&re, c->pattern, REG_EXTENDED))
619                         die("Bogus regex in service table: %s", c->pattern);
620                 if (!regexec(&re, dir, 1, out, 0)) {
621                         size_t n;
622
623                         if (strcmp(method, c->method)) {
624                                 const char *proto = getenv("SERVER_PROTOCOL");
625                                 if (proto && !strcmp(proto, "HTTP/1.1"))
626                                         http_status(405, "Method Not Allowed");
627                                 else
628                                         http_status(400, "Bad Request");
629                                 hdr_nocache();
630                                 end_headers();
631                                 return 0;
632                         }
633
634                         cmd = c;
635                         n = out[0].rm_eo - out[0].rm_so;
636                         cmd_arg = xmalloc(n);
637                         memcpy(cmd_arg, dir + out[0].rm_so + 1, n-1);
638                         cmd_arg[n-1] = '\0';
639                         dir[out[0].rm_so] = 0;
640                         break;
641                 }
642                 regfree(&re);
643         }
644
645         if (!cmd)
646                 not_found("Request not supported: '%s'", dir);
647
648         setup_path();
649         if (!enter_repo(dir, 0))
650                 not_found("Not a git repository: '%s'", dir);
651         if (!getenv("GIT_HTTP_EXPORT_ALL") &&
652             access("git-daemon-export-ok", F_OK) )
653                 not_found("Repository not exported: '%s'", dir);
654
655         git_config(http_config, NULL);
656         cmd->imp(cmd_arg);
657         return 0;
658 }