Sync with 2.15.3
[git] / http-backend.c
1 #include "cache.h"
2 #include "config.h"
3 #include "refs.h"
4 #include "pkt-line.h"
5 #include "object.h"
6 #include "tag.h"
7 #include "exec_cmd.h"
8 #include "run-command.h"
9 #include "string-list.h"
10 #include "url.h"
11 #include "argv-array.h"
12 #include "packfile.h"
13
14 static const char content_type[] = "Content-Type";
15 static const char content_length[] = "Content-Length";
16 static const char last_modified[] = "Last-Modified";
17 static int getanyfile = 1;
18 static unsigned long max_request_buffer = 10 * 1024 * 1024;
19
20 static struct string_list *query_params;
21
22 struct rpc_service {
23         const char *name;
24         const char *config_name;
25         unsigned buffer_input : 1;
26         signed enabled : 2;
27 };
28
29 static struct rpc_service rpc_service[] = {
30         { "upload-pack", "uploadpack", 1, 1 },
31         { "receive-pack", "receivepack", 0, -1 },
32 };
33
34 static struct string_list *get_parameters(void)
35 {
36         if (!query_params) {
37                 const char *query = getenv("QUERY_STRING");
38
39                 query_params = xcalloc(1, sizeof(*query_params));
40                 while (query && *query) {
41                         char *name = url_decode_parameter_name(&query);
42                         char *value = url_decode_parameter_value(&query);
43                         struct string_list_item *i;
44
45                         i = string_list_lookup(query_params, name);
46                         if (!i)
47                                 i = string_list_insert(query_params, name);
48                         else
49                                 free(i->util);
50                         i->util = value;
51                 }
52         }
53         return query_params;
54 }
55
56 static const char *get_parameter(const char *name)
57 {
58         struct string_list_item *i;
59         i = string_list_lookup(get_parameters(), name);
60         return i ? i->util : NULL;
61 }
62
63 __attribute__((format (printf, 2, 3)))
64 static void format_write(int fd, const char *fmt, ...)
65 {
66         static char buffer[1024];
67
68         va_list args;
69         unsigned n;
70
71         va_start(args, fmt);
72         n = vsnprintf(buffer, sizeof(buffer), fmt, args);
73         va_end(args);
74         if (n >= sizeof(buffer))
75                 die("protocol error: impossibly long line");
76
77         write_or_die(fd, buffer, n);
78 }
79
80 static void http_status(struct strbuf *hdr, unsigned code, const char *msg)
81 {
82         strbuf_addf(hdr, "Status: %u %s\r\n", code, msg);
83 }
84
85 static void hdr_str(struct strbuf *hdr, const char *name, const char *value)
86 {
87         strbuf_addf(hdr, "%s: %s\r\n", name, value);
88 }
89
90 static void hdr_int(struct strbuf *hdr, const char *name, uintmax_t value)
91 {
92         strbuf_addf(hdr, "%s: %" PRIuMAX "\r\n", name, value);
93 }
94
95 static void hdr_date(struct strbuf *hdr, const char *name, timestamp_t when)
96 {
97         const char *value = show_date(when, 0, DATE_MODE(RFC2822));
98         hdr_str(hdr, name, value);
99 }
100
101 static void hdr_nocache(struct strbuf *hdr)
102 {
103         hdr_str(hdr, "Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
104         hdr_str(hdr, "Pragma", "no-cache");
105         hdr_str(hdr, "Cache-Control", "no-cache, max-age=0, must-revalidate");
106 }
107
108 static void hdr_cache_forever(struct strbuf *hdr)
109 {
110         timestamp_t now = time(NULL);
111         hdr_date(hdr, "Date", now);
112         hdr_date(hdr, "Expires", now + 31536000);
113         hdr_str(hdr, "Cache-Control", "public, max-age=31536000");
114 }
115
116 static void end_headers(struct strbuf *hdr)
117 {
118         strbuf_add(hdr, "\r\n", 2);
119         write_or_die(1, hdr->buf, hdr->len);
120         strbuf_release(hdr);
121 }
122
123 __attribute__((format (printf, 2, 3)))
124 static NORETURN void not_found(struct strbuf *hdr, const char *err, ...)
125 {
126         va_list params;
127
128         http_status(hdr, 404, "Not Found");
129         hdr_nocache(hdr);
130         end_headers(hdr);
131
132         va_start(params, err);
133         if (err && *err)
134                 vfprintf(stderr, err, params);
135         va_end(params);
136         exit(0);
137 }
138
139 __attribute__((format (printf, 2, 3)))
140 static NORETURN void forbidden(struct strbuf *hdr, const char *err, ...)
141 {
142         va_list params;
143
144         http_status(hdr, 403, "Forbidden");
145         hdr_nocache(hdr);
146         end_headers(hdr);
147
148         va_start(params, err);
149         if (err && *err)
150                 vfprintf(stderr, err, params);
151         va_end(params);
152         exit(0);
153 }
154
155 static void select_getanyfile(struct strbuf *hdr)
156 {
157         if (!getanyfile)
158                 forbidden(hdr, "Unsupported service: getanyfile");
159 }
160
161 static void send_strbuf(struct strbuf *hdr,
162                         const char *type, struct strbuf *buf)
163 {
164         hdr_int(hdr, content_length, buf->len);
165         hdr_str(hdr, content_type, type);
166         end_headers(hdr);
167         write_or_die(1, buf->buf, buf->len);
168 }
169
170 static void send_local_file(struct strbuf *hdr, const char *the_type,
171                                 const char *name)
172 {
173         char *p = git_pathdup("%s", name);
174         size_t buf_alloc = 8192;
175         char *buf = xmalloc(buf_alloc);
176         int fd;
177         struct stat sb;
178
179         fd = open(p, O_RDONLY);
180         if (fd < 0)
181                 not_found(hdr, "Cannot open '%s': %s", p, strerror(errno));
182         if (fstat(fd, &sb) < 0)
183                 die_errno("Cannot stat '%s'", p);
184
185         hdr_int(hdr, content_length, sb.st_size);
186         hdr_str(hdr, content_type, the_type);
187         hdr_date(hdr, last_modified, sb.st_mtime);
188         end_headers(hdr);
189
190         for (;;) {
191                 ssize_t n = xread(fd, buf, buf_alloc);
192                 if (n < 0)
193                         die_errno("Cannot read '%s'", p);
194                 if (!n)
195                         break;
196                 write_or_die(1, buf, n);
197         }
198         close(fd);
199         free(buf);
200         free(p);
201 }
202
203 static void get_text_file(struct strbuf *hdr, char *name)
204 {
205         select_getanyfile(hdr);
206         hdr_nocache(hdr);
207         send_local_file(hdr, "text/plain", name);
208 }
209
210 static void get_loose_object(struct strbuf *hdr, char *name)
211 {
212         select_getanyfile(hdr);
213         hdr_cache_forever(hdr);
214         send_local_file(hdr, "application/x-git-loose-object", name);
215 }
216
217 static void get_pack_file(struct strbuf *hdr, char *name)
218 {
219         select_getanyfile(hdr);
220         hdr_cache_forever(hdr);
221         send_local_file(hdr, "application/x-git-packed-objects", name);
222 }
223
224 static void get_idx_file(struct strbuf *hdr, char *name)
225 {
226         select_getanyfile(hdr);
227         hdr_cache_forever(hdr);
228         send_local_file(hdr, "application/x-git-packed-objects-toc", name);
229 }
230
231 static void http_config(void)
232 {
233         int i, value = 0;
234         struct strbuf var = STRBUF_INIT;
235
236         git_config_get_bool("http.getanyfile", &getanyfile);
237         git_config_get_ulong("http.maxrequestbuffer", &max_request_buffer);
238
239         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
240                 struct rpc_service *svc = &rpc_service[i];
241                 strbuf_addf(&var, "http.%s", svc->config_name);
242                 if (!git_config_get_bool(var.buf, &value))
243                         svc->enabled = value;
244                 strbuf_reset(&var);
245         }
246
247         strbuf_release(&var);
248 }
249
250 static struct rpc_service *select_service(struct strbuf *hdr, const char *name)
251 {
252         const char *svc_name;
253         struct rpc_service *svc = NULL;
254         int i;
255
256         if (!skip_prefix(name, "git-", &svc_name))
257                 forbidden(hdr, "Unsupported service: '%s'", name);
258
259         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
260                 struct rpc_service *s = &rpc_service[i];
261                 if (!strcmp(s->name, svc_name)) {
262                         svc = s;
263                         break;
264                 }
265         }
266
267         if (!svc)
268                 forbidden(hdr, "Unsupported service: '%s'", name);
269
270         if (svc->enabled < 0) {
271                 const char *user = getenv("REMOTE_USER");
272                 svc->enabled = (user && *user) ? 1 : 0;
273         }
274         if (!svc->enabled)
275                 forbidden(hdr, "Service not enabled: '%s'", svc->name);
276         return svc;
277 }
278
279 /*
280  * This is basically strbuf_read(), except that if we
281  * hit max_request_buffer we die (we'd rather reject a
282  * maliciously large request than chew up infinite memory).
283  */
284 static ssize_t read_request(int fd, unsigned char **out)
285 {
286         size_t len = 0, alloc = 8192;
287         unsigned char *buf = xmalloc(alloc);
288
289         if (max_request_buffer < alloc)
290                 max_request_buffer = alloc;
291
292         while (1) {
293                 ssize_t cnt;
294
295                 cnt = read_in_full(fd, buf + len, alloc - len);
296                 if (cnt < 0) {
297                         free(buf);
298                         return -1;
299                 }
300
301                 /* partial read from read_in_full means we hit EOF */
302                 len += cnt;
303                 if (len < alloc) {
304                         *out = buf;
305                         return len;
306                 }
307
308                 /* otherwise, grow and try again (if we can) */
309                 if (alloc == max_request_buffer)
310                         die("request was larger than our maximum size (%lu);"
311                             " try setting GIT_HTTP_MAX_REQUEST_BUFFER",
312                             max_request_buffer);
313
314                 alloc = alloc_nr(alloc);
315                 if (alloc > max_request_buffer)
316                         alloc = max_request_buffer;
317                 REALLOC_ARRAY(buf, alloc);
318         }
319 }
320
321 static void inflate_request(const char *prog_name, int out, int buffer_input)
322 {
323         git_zstream stream;
324         unsigned char *full_request = NULL;
325         unsigned char in_buf[8192];
326         unsigned char out_buf[8192];
327         unsigned long cnt = 0;
328
329         memset(&stream, 0, sizeof(stream));
330         git_inflate_init_gzip_only(&stream);
331
332         while (1) {
333                 ssize_t n;
334
335                 if (buffer_input) {
336                         if (full_request)
337                                 n = 0; /* nothing left to read */
338                         else
339                                 n = read_request(0, &full_request);
340                         stream.next_in = full_request;
341                 } else {
342                         n = xread(0, in_buf, sizeof(in_buf));
343                         stream.next_in = in_buf;
344                 }
345
346                 if (n <= 0)
347                         die("request ended in the middle of the gzip stream");
348                 stream.avail_in = n;
349
350                 while (0 < stream.avail_in) {
351                         int ret;
352
353                         stream.next_out = out_buf;
354                         stream.avail_out = sizeof(out_buf);
355
356                         ret = git_inflate(&stream, Z_NO_FLUSH);
357                         if (ret != Z_OK && ret != Z_STREAM_END)
358                                 die("zlib error inflating request, result %d", ret);
359
360                         n = stream.total_out - cnt;
361                         if (write_in_full(out, out_buf, n) < 0)
362                                 die("%s aborted reading request", prog_name);
363                         cnt += n;
364
365                         if (ret == Z_STREAM_END)
366                                 goto done;
367                 }
368         }
369
370 done:
371         git_inflate_end(&stream);
372         close(out);
373         free(full_request);
374 }
375
376 static void copy_request(const char *prog_name, int out)
377 {
378         unsigned char *buf;
379         ssize_t n = read_request(0, &buf);
380         if (n < 0)
381                 die_errno("error reading request body");
382         if (write_in_full(out, buf, n) < 0)
383                 die("%s aborted reading request", prog_name);
384         close(out);
385         free(buf);
386 }
387
388 static void run_service(const char **argv, int buffer_input)
389 {
390         const char *encoding = getenv("HTTP_CONTENT_ENCODING");
391         const char *user = getenv("REMOTE_USER");
392         const char *host = getenv("REMOTE_ADDR");
393         int gzipped_request = 0;
394         struct child_process cld = CHILD_PROCESS_INIT;
395
396         if (encoding && !strcmp(encoding, "gzip"))
397                 gzipped_request = 1;
398         else if (encoding && !strcmp(encoding, "x-gzip"))
399                 gzipped_request = 1;
400
401         if (!user || !*user)
402                 user = "anonymous";
403         if (!host || !*host)
404                 host = "(none)";
405
406         if (!getenv("GIT_COMMITTER_NAME"))
407                 argv_array_pushf(&cld.env_array, "GIT_COMMITTER_NAME=%s", user);
408         if (!getenv("GIT_COMMITTER_EMAIL"))
409                 argv_array_pushf(&cld.env_array,
410                                  "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
411
412         cld.argv = argv;
413         if (buffer_input || gzipped_request)
414                 cld.in = -1;
415         cld.git_cmd = 1;
416         if (start_command(&cld))
417                 exit(1);
418
419         close(1);
420         if (gzipped_request)
421                 inflate_request(argv[0], cld.in, buffer_input);
422         else if (buffer_input)
423                 copy_request(argv[0], cld.in);
424         else
425                 close(0);
426
427         if (finish_command(&cld))
428                 exit(1);
429 }
430
431 static int show_text_ref(const char *name, const struct object_id *oid,
432                          int flag, void *cb_data)
433 {
434         const char *name_nons = strip_namespace(name);
435         struct strbuf *buf = cb_data;
436         struct object *o = parse_object(oid);
437         if (!o)
438                 return 0;
439
440         strbuf_addf(buf, "%s\t%s\n", oid_to_hex(oid), name_nons);
441         if (o->type == OBJ_TAG) {
442                 o = deref_tag(o, name, 0);
443                 if (!o)
444                         return 0;
445                 strbuf_addf(buf, "%s\t%s^{}\n", oid_to_hex(&o->oid),
446                             name_nons);
447         }
448         return 0;
449 }
450
451 static void get_info_refs(struct strbuf *hdr, char *arg)
452 {
453         const char *service_name = get_parameter("service");
454         struct strbuf buf = STRBUF_INIT;
455
456         hdr_nocache(hdr);
457
458         if (service_name) {
459                 const char *argv[] = {NULL /* service name */,
460                         "--stateless-rpc", "--advertise-refs",
461                         ".", NULL};
462                 struct rpc_service *svc = select_service(hdr, service_name);
463
464                 strbuf_addf(&buf, "application/x-git-%s-advertisement",
465                         svc->name);
466                 hdr_str(hdr, content_type, buf.buf);
467                 end_headers(hdr);
468
469                 packet_write_fmt(1, "# service=git-%s\n", svc->name);
470                 packet_flush(1);
471
472                 argv[0] = svc->name;
473                 run_service(argv, 0);
474
475         } else {
476                 select_getanyfile(hdr);
477                 for_each_namespaced_ref(show_text_ref, &buf);
478                 send_strbuf(hdr, "text/plain", &buf);
479         }
480         strbuf_release(&buf);
481 }
482
483 static int show_head_ref(const char *refname, const struct object_id *oid,
484                          int flag, void *cb_data)
485 {
486         struct strbuf *buf = cb_data;
487
488         if (flag & REF_ISSYMREF) {
489                 const char *target = resolve_ref_unsafe(refname,
490                                                         RESOLVE_REF_READING,
491                                                         NULL, NULL);
492
493                 if (target)
494                         strbuf_addf(buf, "ref: %s\n", strip_namespace(target));
495         } else {
496                 strbuf_addf(buf, "%s\n", oid_to_hex(oid));
497         }
498
499         return 0;
500 }
501
502 static void get_head(struct strbuf *hdr, char *arg)
503 {
504         struct strbuf buf = STRBUF_INIT;
505
506         select_getanyfile(hdr);
507         head_ref_namespaced(show_head_ref, &buf);
508         send_strbuf(hdr, "text/plain", &buf);
509         strbuf_release(&buf);
510 }
511
512 static void get_info_packs(struct strbuf *hdr, char *arg)
513 {
514         size_t objdirlen = strlen(get_object_directory());
515         struct strbuf buf = STRBUF_INIT;
516         struct packed_git *p;
517         size_t cnt = 0;
518
519         select_getanyfile(hdr);
520         prepare_packed_git();
521         for (p = packed_git; p; p = p->next) {
522                 if (p->pack_local)
523                         cnt++;
524         }
525
526         strbuf_grow(&buf, cnt * 53 + 2);
527         for (p = packed_git; p; p = p->next) {
528                 if (p->pack_local)
529                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
530         }
531         strbuf_addch(&buf, '\n');
532
533         hdr_nocache(hdr);
534         send_strbuf(hdr, "text/plain; charset=utf-8", &buf);
535         strbuf_release(&buf);
536 }
537
538 static void check_content_type(struct strbuf *hdr, const char *accepted_type)
539 {
540         const char *actual_type = getenv("CONTENT_TYPE");
541
542         if (!actual_type)
543                 actual_type = "";
544
545         if (strcmp(actual_type, accepted_type)) {
546                 http_status(hdr, 415, "Unsupported Media Type");
547                 hdr_nocache(hdr);
548                 end_headers(hdr);
549                 format_write(1,
550                         "Expected POST with Content-Type '%s',"
551                         " but received '%s' instead.\n",
552                         accepted_type, actual_type);
553                 exit(0);
554         }
555 }
556
557 static void service_rpc(struct strbuf *hdr, char *service_name)
558 {
559         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
560         struct rpc_service *svc = select_service(hdr, service_name);
561         struct strbuf buf = STRBUF_INIT;
562
563         strbuf_reset(&buf);
564         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
565         check_content_type(hdr, buf.buf);
566
567         hdr_nocache(hdr);
568
569         strbuf_reset(&buf);
570         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
571         hdr_str(hdr, content_type, buf.buf);
572
573         end_headers(hdr);
574
575         argv[0] = svc->name;
576         run_service(argv, svc->buffer_input);
577         strbuf_release(&buf);
578 }
579
580 static int dead;
581 static NORETURN void die_webcgi(const char *err, va_list params)
582 {
583         if (dead <= 1) {
584                 struct strbuf hdr = STRBUF_INIT;
585
586                 vreportf("fatal: ", err, params);
587
588                 http_status(&hdr, 500, "Internal Server Error");
589                 hdr_nocache(&hdr);
590                 end_headers(&hdr);
591         }
592         exit(0); /* we successfully reported a failure ;-) */
593 }
594
595 static int die_webcgi_recursing(void)
596 {
597         return dead++ > 1;
598 }
599
600 static char* getdir(void)
601 {
602         struct strbuf buf = STRBUF_INIT;
603         char *pathinfo = getenv("PATH_INFO");
604         char *root = getenv("GIT_PROJECT_ROOT");
605         char *path = getenv("PATH_TRANSLATED");
606
607         if (root && *root) {
608                 if (!pathinfo || !*pathinfo)
609                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
610                 if (daemon_avoid_alias(pathinfo))
611                         die("'%s': aliased", pathinfo);
612                 end_url_with_slash(&buf, root);
613                 if (pathinfo[0] == '/')
614                         pathinfo++;
615                 strbuf_addstr(&buf, pathinfo);
616                 return strbuf_detach(&buf, NULL);
617         } else if (path && *path) {
618                 return xstrdup(path);
619         } else
620                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
621         return NULL;
622 }
623
624 static struct service_cmd {
625         const char *method;
626         const char *pattern;
627         void (*imp)(struct strbuf *, char *);
628 } services[] = {
629         {"GET", "/HEAD$", get_head},
630         {"GET", "/info/refs$", get_info_refs},
631         {"GET", "/objects/info/alternates$", get_text_file},
632         {"GET", "/objects/info/http-alternates$", get_text_file},
633         {"GET", "/objects/info/packs$", get_info_packs},
634         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
635         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
636         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
637
638         {"POST", "/git-upload-pack$", service_rpc},
639         {"POST", "/git-receive-pack$", service_rpc}
640 };
641
642 static int bad_request(struct strbuf *hdr, const struct service_cmd *c)
643 {
644         const char *proto = getenv("SERVER_PROTOCOL");
645
646         if (proto && !strcmp(proto, "HTTP/1.1")) {
647                 http_status(hdr, 405, "Method Not Allowed");
648                 hdr_str(hdr, "Allow",
649                         !strcmp(c->method, "GET") ? "GET, HEAD" : c->method);
650         } else
651                 http_status(hdr, 400, "Bad Request");
652         hdr_nocache(hdr);
653         end_headers(hdr);
654         return 0;
655 }
656
657 int cmd_main(int argc, const char **argv)
658 {
659         char *method = getenv("REQUEST_METHOD");
660         char *dir;
661         struct service_cmd *cmd = NULL;
662         char *cmd_arg = NULL;
663         int i;
664         struct strbuf hdr = STRBUF_INIT;
665
666         set_die_routine(die_webcgi);
667         set_die_is_recursing_routine(die_webcgi_recursing);
668
669         if (!method)
670                 die("No REQUEST_METHOD from server");
671         if (!strcmp(method, "HEAD"))
672                 method = "GET";
673         dir = getdir();
674
675         for (i = 0; i < ARRAY_SIZE(services); i++) {
676                 struct service_cmd *c = &services[i];
677                 regex_t re;
678                 regmatch_t out[1];
679
680                 if (regcomp(&re, c->pattern, REG_EXTENDED))
681                         die("Bogus regex in service table: %s", c->pattern);
682                 if (!regexec(&re, dir, 1, out, 0)) {
683                         size_t n;
684
685                         if (strcmp(method, c->method))
686                                 return bad_request(&hdr, c);
687
688                         cmd = c;
689                         n = out[0].rm_eo - out[0].rm_so;
690                         cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
691                         dir[out[0].rm_so] = 0;
692                         break;
693                 }
694                 regfree(&re);
695         }
696
697         if (!cmd)
698                 not_found(&hdr, "Request not supported: '%s'", dir);
699
700         setup_path();
701         if (!enter_repo(dir, 0))
702                 not_found(&hdr, "Not a git repository: '%s'", dir);
703         if (!getenv("GIT_HTTP_EXPORT_ALL") &&
704             access("git-daemon-export-ok", F_OK) )
705                 not_found(&hdr, "Repository not exported: '%s'", dir);
706
707         http_config();
708         max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER",
709                                            max_request_buffer);
710
711         cmd->imp(&hdr, cmd_arg);
712         return 0;
713 }