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 = CHILD_PROCESS_INIT;
 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         cld.argv = argv;
 345         cld.env = env.argv;
 346         if (gzipped_request)
 347                 cld.in = -1;
 348         cld.git_cmd = 1;
 349         if (start_command(&cld))
 350                 exit(1);
 351
 352         close(1);
 353         if (gzipped_request)
 354                 inflate_request(argv[0], cld.in);
 355         else
 356                 close(0);
 357
 358         if (finish_command(&cld))
 359                 exit(1);
 360         argv_array_clear(&env);
 361 }
 362
 363 static int show_text_ref(const char *name, const unsigned char *sha1,
 364         int flag, void *cb_data)
 365 {
 366         const char *name_nons = strip_namespace(name);
 367         struct strbuf *buf = cb_data;
 368         struct object *o = parse_object(sha1);
 369         if (!o)
 370                 return 0;
 371
 372         strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name_nons);
 373         if (o->type == OBJ_TAG) {
 374                 o = deref_tag(o, name, 0);
 375                 if (!o)
 376                         return 0;
 377                 strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1),
 378                             name_nons);
 379         }
 380         return 0;
 381 }
 382
 383 static void get_info_refs(char *arg)
 384 {
 385         const char *service_name = get_parameter("service");
 386         struct strbuf buf = STRBUF_INIT;
 387
 388         hdr_nocache();
 389
 390         if (service_name) {
 391                 const char *argv[] = {NULL /* service name */,
 392                         "--stateless-rpc", "--advertise-refs",
 393                         ".", NULL};
 394                 struct rpc_service *svc = select_service(service_name);
 395
 396                 strbuf_addf(&buf, "application/x-git-%s-advertisement",
 397                         svc->name);
 398                 hdr_str(content_type, buf.buf);
 399                 end_headers();
 400
 401                 packet_write(1, "# service=git-%s\n", svc->name);
 402                 packet_flush(1);
 403
 404                 argv[0] = svc->name;
 405                 run_service(argv);
 406
 407         } else {
 408                 select_getanyfile();
 409                 for_each_namespaced_ref(show_text_ref, &buf);
 410                 send_strbuf("text/plain", &buf);
 411         }
 412         strbuf_release(&buf);
 413 }
 414
 415 static int show_head_ref(const char *refname, const unsigned char *sha1,
 416         int flag, void *cb_data)
 417 {
 418         struct strbuf *buf = cb_data;
 419
 420         if (flag & REF_ISSYMREF) {
 421                 unsigned char unused[20];
 422                 const char *target = resolve_ref_unsafe(refname, unused, 1, NULL);
 423                 const char *target_nons = strip_namespace(target);
 424
 425                 strbuf_addf(buf, "ref: %s\n", target_nons);
 426         } else {
 427                 strbuf_addf(buf, "%s\n", sha1_to_hex(sha1));
 428         }
 429
 430         return 0;
 431 }
 432
 433 static void get_head(char *arg)
 434 {
 435         struct strbuf buf = STRBUF_INIT;
 436
 437         select_getanyfile();
 438         head_ref_namespaced(show_head_ref, &buf);
 439         send_strbuf("text/plain", &buf);
 440         strbuf_release(&buf);
 441 }
 442
 443 static void get_info_packs(char *arg)
 444 {
 445         size_t objdirlen = strlen(get_object_directory());
 446         struct strbuf buf = STRBUF_INIT;
 447         struct packed_git *p;
 448         size_t cnt = 0;
 449
 450         select_getanyfile();
 451         prepare_packed_git();
 452         for (p = packed_git; p; p = p->next) {
 453                 if (p->pack_local)
 454                         cnt++;
 455         }
 456
 457         strbuf_grow(&buf, cnt * 53 + 2);
 458         for (p = packed_git; p; p = p->next) {
 459                 if (p->pack_local)
 460                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
 461         }
 462         strbuf_addch(&buf, '\n');
 463
 464         hdr_nocache();
 465         send_strbuf("text/plain; charset=utf-8", &buf);
 466         strbuf_release(&buf);
 467 }
 468
 469 static void check_content_type(const char *accepted_type)
 470 {
 471         const char *actual_type = getenv("CONTENT_TYPE");
 472
 473         if (!actual_type)
 474                 actual_type = "";
 475
 476         if (strcmp(actual_type, accepted_type)) {
 477                 http_status(415, "Unsupported Media Type");
 478                 hdr_nocache();
 479                 end_headers();
 480                 format_write(1,
 481                         "Expected POST with Content-Type '%s',"
 482                         " but received '%s' instead.\n",
 483                         accepted_type, actual_type);
 484                 exit(0);
 485         }
 486 }
 487
 488 static void service_rpc(char *service_name)
 489 {
 490         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
 491         struct rpc_service *svc = select_service(service_name);
 492         struct strbuf buf = STRBUF_INIT;
 493
 494         strbuf_reset(&buf);
 495         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
 496         check_content_type(buf.buf);
 497
 498         hdr_nocache();
 499
 500         strbuf_reset(&buf);
 501         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
 502         hdr_str(content_type, buf.buf);
 503
 504         end_headers();
 505
 506         argv[0] = svc->name;
 507         run_service(argv);
 508         strbuf_release(&buf);
 509 }
 510
 511 static NORETURN void die_webcgi(const char *err, va_list params)
 512 {
 513         static int dead;
 514
 515         if (!dead) {
 516                 dead = 1;
 517                 http_status(500, "Internal Server Error");
 518                 hdr_nocache();
 519                 end_headers();
 520
 521                 vreportf("fatal: ", err, params);
 522         }
 523         exit(0); /* we successfully reported a failure ;-) */
 524 }
 525
 526 static char* getdir(void)
 527 {
 528         struct strbuf buf = STRBUF_INIT;
 529         char *pathinfo = getenv("PATH_INFO");
 530         char *root = getenv("GIT_PROJECT_ROOT");
 531         char *path = getenv("PATH_TRANSLATED");
 532
 533         if (root && *root) {
 534                 if (!pathinfo || !*pathinfo)
 535                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
 536                 if (daemon_avoid_alias(pathinfo))
 537                         die("'%s': aliased", pathinfo);
 538                 end_url_with_slash(&buf, root);
 539                 if (pathinfo[0] == '/')
 540                         pathinfo++;
 541                 strbuf_addstr(&buf, pathinfo);
 542                 return strbuf_detach(&buf, NULL);
 543         } else if (path && *path) {
 544                 return xstrdup(path);
 545         } else
 546                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
 547         return NULL;
 548 }
 549
 550 static struct service_cmd {
 551         const char *method;
 552         const char *pattern;
 553         void (*imp)(char *);
 554 } services[] = {
 555         {"GET", "/HEAD$", get_head},
 556         {"GET", "/info/refs$", get_info_refs},
 557         {"GET", "/objects/info/alternates$", get_text_file},
 558         {"GET", "/objects/info/http-alternates$", get_text_file},
 559         {"GET", "/objects/info/packs$", get_info_packs},
 560         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
 561         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
 562         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
 563
 564         {"POST", "/git-upload-pack$", service_rpc},
 565         {"POST", "/git-receive-pack$", service_rpc}
 566 };
 567
 568 int main(int argc, char **argv)
 569 {
 570         char *method = getenv("REQUEST_METHOD");
 571         char *dir;
 572         struct service_cmd *cmd = NULL;
 573         char *cmd_arg = NULL;
 574         int i;
 575
 576         git_setup_gettext();
 577
 578         git_extract_argv0_path(argv[0]);
 579         set_die_routine(die_webcgi);
 580
 581         if (!method)
 582                 die("No REQUEST_METHOD from server");
 583         if (!strcmp(method, "HEAD"))
 584                 method = "GET";
 585         dir = getdir();
 586
 587         for (i = 0; i < ARRAY_SIZE(services); i++) {
 588                 struct service_cmd *c = &services[i];
 589                 regex_t re;
 590                 regmatch_t out[1];
 591
 592                 if (regcomp(&re, c->pattern, REG_EXTENDED))
 593                         die("Bogus regex in service table: %s", c->pattern);
 594                 if (!regexec(&re, dir, 1, out, 0)) {
 595                         size_t n;
 596
 597                         if (strcmp(method, c->method)) {
 598                                 const char *proto = getenv("SERVER_PROTOCOL");
 599                                 if (proto && !strcmp(proto, "HTTP/1.1")) {
 600                                         http_status(405, "Method Not Allowed");
 601                                         hdr_str("Allow", !strcmp(c->method, "GET") ?
 602                                                 "GET, HEAD" : c->method);
 603                                 } else
 604                                         http_status(400, "Bad Request");
 605                                 hdr_nocache();
 606                                 end_headers();
 607                                 return 0;
 608                         }
 609
 610                         cmd = c;
 611                         n = out[0].rm_eo - out[0].rm_so;
 612                         cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
 613                         dir[out[0].rm_so] = 0;
 614                         break;
 615                 }
 616                 regfree(&re);
 617         }
 618
 619         if (!cmd)
 620                 not_found("Request not supported: '%s'", dir);
 621
 622         setup_path();
 623         if (!enter_repo(dir, 0))
 624                 not_found("Not a git repository: '%s'", dir);
 625         if (!getenv("GIT_HTTP_EXPORT_ALL") &&
 626             access("git-daemon-export-ok", F_OK) )
 627                 not_found("Repository not exported: '%s'", dir);
 628
 629         git_config(http_config, NULL);
 630         cmd->imp(cmd_arg);
 631         return 0;
 632 }