Merge branch 'eb/cred-helper-ignore-sigpipe'
[git] / http-backend.c
1 #include "cache.h"
2 #include "config.h"
3 #include "repository.h"
4 #include "refs.h"
5 #include "pkt-line.h"
6 #include "object.h"
7 #include "tag.h"
8 #include "exec_cmd.h"
9 #include "run-command.h"
10 #include "string-list.h"
11 #include "url.h"
12 #include "argv-array.h"
13 #include "packfile.h"
14 #include "object-store.h"
15
16 static const char content_type[] = "Content-Type";
17 static const char content_length[] = "Content-Length";
18 static const char last_modified[] = "Last-Modified";
19 static int getanyfile = 1;
20 static unsigned long max_request_buffer = 10 * 1024 * 1024;
21
22 static struct string_list *query_params;
23
24 struct rpc_service {
25         const char *name;
26         const char *config_name;
27         unsigned buffer_input : 1;
28         signed enabled : 2;
29 };
30
31 static struct rpc_service rpc_service[] = {
32         { "upload-pack", "uploadpack", 1, 1 },
33         { "receive-pack", "receivepack", 0, -1 },
34 };
35
36 static struct string_list *get_parameters(void)
37 {
38         if (!query_params) {
39                 const char *query = getenv("QUERY_STRING");
40
41                 query_params = xcalloc(1, sizeof(*query_params));
42                 while (query && *query) {
43                         char *name = url_decode_parameter_name(&query);
44                         char *value = url_decode_parameter_value(&query);
45                         struct string_list_item *i;
46
47                         i = string_list_lookup(query_params, name);
48                         if (!i)
49                                 i = string_list_insert(query_params, name);
50                         else
51                                 free(i->util);
52                         i->util = value;
53                 }
54         }
55         return query_params;
56 }
57
58 static const char *get_parameter(const char *name)
59 {
60         struct string_list_item *i;
61         i = string_list_lookup(get_parameters(), name);
62         return i ? i->util : NULL;
63 }
64
65 __attribute__((format (printf, 2, 3)))
66 static void format_write(int fd, const char *fmt, ...)
67 {
68         static char buffer[1024];
69
70         va_list args;
71         unsigned n;
72
73         va_start(args, fmt);
74         n = vsnprintf(buffer, sizeof(buffer), fmt, args);
75         va_end(args);
76         if (n >= sizeof(buffer))
77                 die("protocol error: impossibly long line");
78
79         write_or_die(fd, buffer, n);
80 }
81
82 static void http_status(struct strbuf *hdr, unsigned code, const char *msg)
83 {
84         strbuf_addf(hdr, "Status: %u %s\r\n", code, msg);
85 }
86
87 static void hdr_str(struct strbuf *hdr, const char *name, const char *value)
88 {
89         strbuf_addf(hdr, "%s: %s\r\n", name, value);
90 }
91
92 static void hdr_int(struct strbuf *hdr, const char *name, uintmax_t value)
93 {
94         strbuf_addf(hdr, "%s: %" PRIuMAX "\r\n", name, value);
95 }
96
97 static void hdr_date(struct strbuf *hdr, const char *name, timestamp_t when)
98 {
99         const char *value = show_date(when, 0, DATE_MODE(RFC2822));
100         hdr_str(hdr, name, value);
101 }
102
103 static void hdr_nocache(struct strbuf *hdr)
104 {
105         hdr_str(hdr, "Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
106         hdr_str(hdr, "Pragma", "no-cache");
107         hdr_str(hdr, "Cache-Control", "no-cache, max-age=0, must-revalidate");
108 }
109
110 static void hdr_cache_forever(struct strbuf *hdr)
111 {
112         timestamp_t now = time(NULL);
113         hdr_date(hdr, "Date", now);
114         hdr_date(hdr, "Expires", now + 31536000);
115         hdr_str(hdr, "Cache-Control", "public, max-age=31536000");
116 }
117
118 static void end_headers(struct strbuf *hdr)
119 {
120         strbuf_add(hdr, "\r\n", 2);
121         write_or_die(1, hdr->buf, hdr->len);
122         strbuf_release(hdr);
123 }
124
125 __attribute__((format (printf, 2, 3)))
126 static NORETURN void not_found(struct strbuf *hdr, const char *err, ...)
127 {
128         va_list params;
129
130         http_status(hdr, 404, "Not Found");
131         hdr_nocache(hdr);
132         end_headers(hdr);
133
134         va_start(params, err);
135         if (err && *err)
136                 vfprintf(stderr, err, params);
137         va_end(params);
138         exit(0);
139 }
140
141 __attribute__((format (printf, 2, 3)))
142 static NORETURN void forbidden(struct strbuf *hdr, const char *err, ...)
143 {
144         va_list params;
145
146         http_status(hdr, 403, "Forbidden");
147         hdr_nocache(hdr);
148         end_headers(hdr);
149
150         va_start(params, err);
151         if (err && *err)
152                 vfprintf(stderr, err, params);
153         va_end(params);
154         exit(0);
155 }
156
157 static void select_getanyfile(struct strbuf *hdr)
158 {
159         if (!getanyfile)
160                 forbidden(hdr, "Unsupported service: getanyfile");
161 }
162
163 static void send_strbuf(struct strbuf *hdr,
164                         const char *type, struct strbuf *buf)
165 {
166         hdr_int(hdr, content_length, buf->len);
167         hdr_str(hdr, content_type, type);
168         end_headers(hdr);
169         write_or_die(1, buf->buf, buf->len);
170 }
171
172 static void send_local_file(struct strbuf *hdr, const char *the_type,
173                                 const char *name)
174 {
175         char *p = git_pathdup("%s", name);
176         size_t buf_alloc = 8192;
177         char *buf = xmalloc(buf_alloc);
178         int fd;
179         struct stat sb;
180
181         fd = open(p, O_RDONLY);
182         if (fd < 0)
183                 not_found(hdr, "Cannot open '%s': %s", p, strerror(errno));
184         if (fstat(fd, &sb) < 0)
185                 die_errno("Cannot stat '%s'", p);
186
187         hdr_int(hdr, content_length, sb.st_size);
188         hdr_str(hdr, content_type, the_type);
189         hdr_date(hdr, last_modified, sb.st_mtime);
190         end_headers(hdr);
191
192         for (;;) {
193                 ssize_t n = xread(fd, buf, buf_alloc);
194                 if (n < 0)
195                         die_errno("Cannot read '%s'", p);
196                 if (!n)
197                         break;
198                 write_or_die(1, buf, n);
199         }
200         close(fd);
201         free(buf);
202         free(p);
203 }
204
205 static void get_text_file(struct strbuf *hdr, char *name)
206 {
207         select_getanyfile(hdr);
208         hdr_nocache(hdr);
209         send_local_file(hdr, "text/plain", name);
210 }
211
212 static void get_loose_object(struct strbuf *hdr, char *name)
213 {
214         select_getanyfile(hdr);
215         hdr_cache_forever(hdr);
216         send_local_file(hdr, "application/x-git-loose-object", name);
217 }
218
219 static void get_pack_file(struct strbuf *hdr, char *name)
220 {
221         select_getanyfile(hdr);
222         hdr_cache_forever(hdr);
223         send_local_file(hdr, "application/x-git-packed-objects", name);
224 }
225
226 static void get_idx_file(struct strbuf *hdr, char *name)
227 {
228         select_getanyfile(hdr);
229         hdr_cache_forever(hdr);
230         send_local_file(hdr, "application/x-git-packed-objects-toc", name);
231 }
232
233 static void http_config(void)
234 {
235         int i, value = 0;
236         struct strbuf var = STRBUF_INIT;
237
238         git_config_get_bool("http.getanyfile", &getanyfile);
239         git_config_get_ulong("http.maxrequestbuffer", &max_request_buffer);
240
241         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
242                 struct rpc_service *svc = &rpc_service[i];
243                 strbuf_addf(&var, "http.%s", svc->config_name);
244                 if (!git_config_get_bool(var.buf, &value))
245                         svc->enabled = value;
246                 strbuf_reset(&var);
247         }
248
249         strbuf_release(&var);
250 }
251
252 static struct rpc_service *select_service(struct strbuf *hdr, const char *name)
253 {
254         const char *svc_name;
255         struct rpc_service *svc = NULL;
256         int i;
257
258         if (!skip_prefix(name, "git-", &svc_name))
259                 forbidden(hdr, "Unsupported service: '%s'", name);
260
261         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
262                 struct rpc_service *s = &rpc_service[i];
263                 if (!strcmp(s->name, svc_name)) {
264                         svc = s;
265                         break;
266                 }
267         }
268
269         if (!svc)
270                 forbidden(hdr, "Unsupported service: '%s'", name);
271
272         if (svc->enabled < 0) {
273                 const char *user = getenv("REMOTE_USER");
274                 svc->enabled = (user && *user) ? 1 : 0;
275         }
276         if (!svc->enabled)
277                 forbidden(hdr, "Service not enabled: '%s'", svc->name);
278         return svc;
279 }
280
281 /*
282  * This is basically strbuf_read(), except that if we
283  * hit max_request_buffer we die (we'd rather reject a
284  * maliciously large request than chew up infinite memory).
285  */
286 static ssize_t read_request(int fd, unsigned char **out)
287 {
288         size_t len = 0, alloc = 8192;
289         unsigned char *buf = xmalloc(alloc);
290
291         if (max_request_buffer < alloc)
292                 max_request_buffer = alloc;
293
294         while (1) {
295                 ssize_t cnt;
296
297                 cnt = read_in_full(fd, buf + len, alloc - len);
298                 if (cnt < 0) {
299                         free(buf);
300                         return -1;
301                 }
302
303                 /* partial read from read_in_full means we hit EOF */
304                 len += cnt;
305                 if (len < alloc) {
306                         *out = buf;
307                         return len;
308                 }
309
310                 /* otherwise, grow and try again (if we can) */
311                 if (alloc == max_request_buffer)
312                         die("request was larger than our maximum size (%lu);"
313                             " try setting GIT_HTTP_MAX_REQUEST_BUFFER",
314                             max_request_buffer);
315
316                 alloc = alloc_nr(alloc);
317                 if (alloc > max_request_buffer)
318                         alloc = max_request_buffer;
319                 REALLOC_ARRAY(buf, alloc);
320         }
321 }
322
323 static void inflate_request(const char *prog_name, int out, int buffer_input)
324 {
325         git_zstream stream;
326         unsigned char *full_request = NULL;
327         unsigned char in_buf[8192];
328         unsigned char out_buf[8192];
329         unsigned long cnt = 0;
330
331         memset(&stream, 0, sizeof(stream));
332         git_inflate_init_gzip_only(&stream);
333
334         while (1) {
335                 ssize_t n;
336
337                 if (buffer_input) {
338                         if (full_request)
339                                 n = 0; /* nothing left to read */
340                         else
341                                 n = read_request(0, &full_request);
342                         stream.next_in = full_request;
343                 } else {
344                         n = xread(0, in_buf, sizeof(in_buf));
345                         stream.next_in = in_buf;
346                 }
347
348                 if (n <= 0)
349                         die("request ended in the middle of the gzip stream");
350                 stream.avail_in = n;
351
352                 while (0 < stream.avail_in) {
353                         int ret;
354
355                         stream.next_out = out_buf;
356                         stream.avail_out = sizeof(out_buf);
357
358                         ret = git_inflate(&stream, Z_NO_FLUSH);
359                         if (ret != Z_OK && ret != Z_STREAM_END)
360                                 die("zlib error inflating request, result %d", ret);
361
362                         n = stream.total_out - cnt;
363                         if (write_in_full(out, out_buf, n) < 0)
364                                 die("%s aborted reading request", prog_name);
365                         cnt += n;
366
367                         if (ret == Z_STREAM_END)
368                                 goto done;
369                 }
370         }
371
372 done:
373         git_inflate_end(&stream);
374         close(out);
375         free(full_request);
376 }
377
378 static void copy_request(const char *prog_name, int out)
379 {
380         unsigned char *buf;
381         ssize_t n = read_request(0, &buf);
382         if (n < 0)
383                 die_errno("error reading request body");
384         if (write_in_full(out, buf, n) < 0)
385                 die("%s aborted reading request", prog_name);
386         close(out);
387         free(buf);
388 }
389
390 static void run_service(const char **argv, int buffer_input)
391 {
392         const char *encoding = getenv("HTTP_CONTENT_ENCODING");
393         const char *user = getenv("REMOTE_USER");
394         const char *host = getenv("REMOTE_ADDR");
395         int gzipped_request = 0;
396         struct child_process cld = CHILD_PROCESS_INIT;
397
398         if (encoding && !strcmp(encoding, "gzip"))
399                 gzipped_request = 1;
400         else if (encoding && !strcmp(encoding, "x-gzip"))
401                 gzipped_request = 1;
402
403         if (!user || !*user)
404                 user = "anonymous";
405         if (!host || !*host)
406                 host = "(none)";
407
408         if (!getenv("GIT_COMMITTER_NAME"))
409                 argv_array_pushf(&cld.env_array, "GIT_COMMITTER_NAME=%s", user);
410         if (!getenv("GIT_COMMITTER_EMAIL"))
411                 argv_array_pushf(&cld.env_array,
412                                  "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
413
414         cld.argv = argv;
415         if (buffer_input || gzipped_request)
416                 cld.in = -1;
417         cld.git_cmd = 1;
418         if (start_command(&cld))
419                 exit(1);
420
421         close(1);
422         if (gzipped_request)
423                 inflate_request(argv[0], cld.in, buffer_input);
424         else if (buffer_input)
425                 copy_request(argv[0], cld.in);
426         else
427                 close(0);
428
429         if (finish_command(&cld))
430                 exit(1);
431 }
432
433 static int show_text_ref(const char *name, const struct object_id *oid,
434                          int flag, void *cb_data)
435 {
436         const char *name_nons = strip_namespace(name);
437         struct strbuf *buf = cb_data;
438         struct object *o = parse_object(oid);
439         if (!o)
440                 return 0;
441
442         strbuf_addf(buf, "%s\t%s\n", oid_to_hex(oid), name_nons);
443         if (o->type == OBJ_TAG) {
444                 o = deref_tag(o, name, 0);
445                 if (!o)
446                         return 0;
447                 strbuf_addf(buf, "%s\t%s^{}\n", oid_to_hex(&o->oid),
448                             name_nons);
449         }
450         return 0;
451 }
452
453 static void get_info_refs(struct strbuf *hdr, char *arg)
454 {
455         const char *service_name = get_parameter("service");
456         struct strbuf buf = STRBUF_INIT;
457
458         hdr_nocache(hdr);
459
460         if (service_name) {
461                 const char *argv[] = {NULL /* service name */,
462                         "--stateless-rpc", "--advertise-refs",
463                         ".", NULL};
464                 struct rpc_service *svc = select_service(hdr, service_name);
465
466                 strbuf_addf(&buf, "application/x-git-%s-advertisement",
467                         svc->name);
468                 hdr_str(hdr, content_type, buf.buf);
469                 end_headers(hdr);
470
471                 packet_write_fmt(1, "# service=git-%s\n", svc->name);
472                 packet_flush(1);
473
474                 argv[0] = svc->name;
475                 run_service(argv, 0);
476
477         } else {
478                 select_getanyfile(hdr);
479                 for_each_namespaced_ref(show_text_ref, &buf);
480                 send_strbuf(hdr, "text/plain", &buf);
481         }
482         strbuf_release(&buf);
483 }
484
485 static int show_head_ref(const char *refname, const struct object_id *oid,
486                          int flag, void *cb_data)
487 {
488         struct strbuf *buf = cb_data;
489
490         if (flag & REF_ISSYMREF) {
491                 const char *target = resolve_ref_unsafe(refname,
492                                                         RESOLVE_REF_READING,
493                                                         NULL, NULL);
494
495                 if (target)
496                         strbuf_addf(buf, "ref: %s\n", strip_namespace(target));
497         } else {
498                 strbuf_addf(buf, "%s\n", oid_to_hex(oid));
499         }
500
501         return 0;
502 }
503
504 static void get_head(struct strbuf *hdr, char *arg)
505 {
506         struct strbuf buf = STRBUF_INIT;
507
508         select_getanyfile(hdr);
509         head_ref_namespaced(show_head_ref, &buf);
510         send_strbuf(hdr, "text/plain", &buf);
511         strbuf_release(&buf);
512 }
513
514 static void get_info_packs(struct strbuf *hdr, char *arg)
515 {
516         size_t objdirlen = strlen(get_object_directory());
517         struct strbuf buf = STRBUF_INIT;
518         struct packed_git *p;
519         size_t cnt = 0;
520
521         select_getanyfile(hdr);
522         for (p = get_packed_git(the_repository); p; p = p->next) {
523                 if (p->pack_local)
524                         cnt++;
525         }
526
527         strbuf_grow(&buf, cnt * 53 + 2);
528         for (p = get_packed_git(the_repository); p; p = p->next) {
529                 if (p->pack_local)
530                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
531         }
532         strbuf_addch(&buf, '\n');
533
534         hdr_nocache(hdr);
535         send_strbuf(hdr, "text/plain; charset=utf-8", &buf);
536         strbuf_release(&buf);
537 }
538
539 static void check_content_type(struct strbuf *hdr, const char *accepted_type)
540 {
541         const char *actual_type = getenv("CONTENT_TYPE");
542
543         if (!actual_type)
544                 actual_type = "";
545
546         if (strcmp(actual_type, accepted_type)) {
547                 http_status(hdr, 415, "Unsupported Media Type");
548                 hdr_nocache(hdr);
549                 end_headers(hdr);
550                 format_write(1,
551                         "Expected POST with Content-Type '%s',"
552                         " but received '%s' instead.\n",
553                         accepted_type, actual_type);
554                 exit(0);
555         }
556 }
557
558 static void service_rpc(struct strbuf *hdr, char *service_name)
559 {
560         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
561         struct rpc_service *svc = select_service(hdr, service_name);
562         struct strbuf buf = STRBUF_INIT;
563
564         strbuf_reset(&buf);
565         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
566         check_content_type(hdr, buf.buf);
567
568         hdr_nocache(hdr);
569
570         strbuf_reset(&buf);
571         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
572         hdr_str(hdr, content_type, buf.buf);
573
574         end_headers(hdr);
575
576         argv[0] = svc->name;
577         run_service(argv, svc->buffer_input);
578         strbuf_release(&buf);
579 }
580
581 static int dead;
582 static NORETURN void die_webcgi(const char *err, va_list params)
583 {
584         if (dead <= 1) {
585                 struct strbuf hdr = STRBUF_INIT;
586
587                 vreportf("fatal: ", err, params);
588
589                 http_status(&hdr, 500, "Internal Server Error");
590                 hdr_nocache(&hdr);
591                 end_headers(&hdr);
592         }
593         exit(0); /* we successfully reported a failure ;-) */
594 }
595
596 static int die_webcgi_recursing(void)
597 {
598         return dead++ > 1;
599 }
600
601 static char* getdir(void)
602 {
603         struct strbuf buf = STRBUF_INIT;
604         char *pathinfo = getenv("PATH_INFO");
605         char *root = getenv("GIT_PROJECT_ROOT");
606         char *path = getenv("PATH_TRANSLATED");
607
608         if (root && *root) {
609                 if (!pathinfo || !*pathinfo)
610                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
611                 if (daemon_avoid_alias(pathinfo))
612                         die("'%s': aliased", pathinfo);
613                 end_url_with_slash(&buf, root);
614                 if (pathinfo[0] == '/')
615                         pathinfo++;
616                 strbuf_addstr(&buf, pathinfo);
617                 return strbuf_detach(&buf, NULL);
618         } else if (path && *path) {
619                 return xstrdup(path);
620         } else
621                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
622         return NULL;
623 }
624
625 static struct service_cmd {
626         const char *method;
627         const char *pattern;
628         void (*imp)(struct strbuf *, char *);
629 } services[] = {
630         {"GET", "/HEAD$", get_head},
631         {"GET", "/info/refs$", get_info_refs},
632         {"GET", "/objects/info/alternates$", get_text_file},
633         {"GET", "/objects/info/http-alternates$", get_text_file},
634         {"GET", "/objects/info/packs$", get_info_packs},
635         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
636         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
637         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
638
639         {"POST", "/git-upload-pack$", service_rpc},
640         {"POST", "/git-receive-pack$", service_rpc}
641 };
642
643 static int bad_request(struct strbuf *hdr, const struct service_cmd *c)
644 {
645         const char *proto = getenv("SERVER_PROTOCOL");
646
647         if (proto && !strcmp(proto, "HTTP/1.1")) {
648                 http_status(hdr, 405, "Method Not Allowed");
649                 hdr_str(hdr, "Allow",
650                         !strcmp(c->method, "GET") ? "GET, HEAD" : c->method);
651         } else
652                 http_status(hdr, 400, "Bad Request");
653         hdr_nocache(hdr);
654         end_headers(hdr);
655         return 0;
656 }
657
658 int cmd_main(int argc, const char **argv)
659 {
660         char *method = getenv("REQUEST_METHOD");
661         char *dir;
662         struct service_cmd *cmd = NULL;
663         char *cmd_arg = NULL;
664         int i;
665         struct strbuf hdr = STRBUF_INIT;
666
667         set_die_routine(die_webcgi);
668         set_die_is_recursing_routine(die_webcgi_recursing);
669
670         if (!method)
671                 die("No REQUEST_METHOD from server");
672         if (!strcmp(method, "HEAD"))
673                 method = "GET";
674         dir = getdir();
675
676         for (i = 0; i < ARRAY_SIZE(services); i++) {
677                 struct service_cmd *c = &services[i];
678                 regex_t re;
679                 regmatch_t out[1];
680
681                 if (regcomp(&re, c->pattern, REG_EXTENDED))
682                         die("Bogus regex in service table: %s", c->pattern);
683                 if (!regexec(&re, dir, 1, out, 0)) {
684                         size_t n;
685
686                         if (strcmp(method, c->method))
687                                 return bad_request(&hdr, c);
688
689                         cmd = c;
690                         n = out[0].rm_eo - out[0].rm_so;
691                         cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
692                         dir[out[0].rm_so] = 0;
693                         break;
694                 }
695                 regfree(&re);
696         }
697
698         if (!cmd)
699                 not_found(&hdr, "Request not supported: '%s'", dir);
700
701         setup_path();
702         if (!enter_repo(dir, 0))
703                 not_found(&hdr, "Not a git repository: '%s'", dir);
704         if (!getenv("GIT_HTTP_EXPORT_ALL") &&
705             access("git-daemon-export-ok", F_OK) )
706                 not_found(&hdr, "Repository not exported: '%s'", dir);
707
708         http_config();
709         max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER",
710                                            max_request_buffer);
711
712         cmd->imp(&hdr, cmd_arg);
713         return 0;
714 }