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 static unsigned long max_request_buffer = 10 * 1024 * 1024;
  17
  18 static struct string_list *query_params;
  19
  20 struct rpc_service {
  21         const char *name;
  22         const char *config_name;
  23         unsigned buffer_input : 1;
  24         signed enabled : 2;
  25 };
  26
  27 static struct rpc_service rpc_service[] = {
  28         { "upload-pack", "uploadpack", 1, 1 },
  29         { "receive-pack", "receivepack", 0, -1 },
  30 };
  31
  32 static struct string_list *get_parameters(void)
  33 {
  34         if (!query_params) {
  35                 const char *query = getenv("QUERY_STRING");
  36
  37                 query_params = xcalloc(1, sizeof(*query_params));
  38                 while (query && *query) {
  39                         char *name = url_decode_parameter_name(&query);
  40                         char *value = url_decode_parameter_value(&query);
  41                         struct string_list_item *i;
  42
  43                         i = string_list_lookup(query_params, name);
  44                         if (!i)
  45                                 i = string_list_insert(query_params, name);
  46                         else
  47                                 free(i->util);
  48                         i->util = value;
  49                 }
  50         }
  51         return query_params;
  52 }
  53
  54 static const char *get_parameter(const char *name)
  55 {
  56         struct string_list_item *i;
  57         i = string_list_lookup(get_parameters(), name);
  58         return i ? i->util : NULL;
  59 }
  60
  61 __attribute__((format (printf, 2, 3)))
  62 static void format_write(int fd, const char *fmt, ...)
  63 {
  64         static char buffer[1024];
  65
  66         va_list args;
  67         unsigned n;
  68
  69         va_start(args, fmt);
  70         n = vsnprintf(buffer, sizeof(buffer), fmt, args);
  71         va_end(args);
  72         if (n >= sizeof(buffer))
  73                 die("protocol error: impossibly long line");
  74
  75         write_or_die(fd, buffer, n);
  76 }
  77
  78 static void http_status(unsigned code, const char *msg)
  79 {
  80         format_write(1, "Status: %u %s\r\n", code, msg);
  81 }
  82
  83 static void hdr_str(const char *name, const char *value)
  84 {
  85         format_write(1, "%s: %s\r\n", name, value);
  86 }
  87
  88 static void hdr_int(const char *name, uintmax_t value)
  89 {
  90         format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
  91 }
  92
  93 static void hdr_date(const char *name, unsigned long when)
  94 {
  95         const char *value = show_date(when, 0, DATE_RFC2822);
  96         hdr_str(name, value);
  97 }
  98
  99 static void hdr_nocache(void)
 100 {
 101         hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
 102         hdr_str("Pragma", "no-cache");
 103         hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate");
 104 }
 105
 106 static void hdr_cache_forever(void)
 107 {
 108         unsigned long now = time(NULL);
 109         hdr_date("Date", now);
 110         hdr_date("Expires", now + 31536000);
 111         hdr_str("Cache-Control", "public, max-age=31536000");
 112 }
 113
 114 static void end_headers(void)
 115 {
 116         write_or_die(1, "\r\n", 2);
 117 }
 118
 119 __attribute__((format (printf, 1, 2)))
 120 static NORETURN void not_found(const char *err, ...)
 121 {
 122         va_list params;
 123
 124         http_status(404, "Not Found");
 125         hdr_nocache();
 126         end_headers();
 127
 128         va_start(params, err);
 129         if (err && *err)
 130                 vfprintf(stderr, err, params);
 131         va_end(params);
 132         exit(0);
 133 }
 134
 135 __attribute__((format (printf, 1, 2)))
 136 static NORETURN void forbidden(const char *err, ...)
 137 {
 138         va_list params;
 139
 140         http_status(403, "Forbidden");
 141         hdr_nocache();
 142         end_headers();
 143
 144         va_start(params, err);
 145         if (err && *err)
 146                 vfprintf(stderr, err, params);
 147         va_end(params);
 148         exit(0);
 149 }
 150
 151 static void select_getanyfile(void)
 152 {
 153         if (!getanyfile)
 154                 forbidden("Unsupported service: getanyfile");
 155 }
 156
 157 static void send_strbuf(const char *type, struct strbuf *buf)
 158 {
 159         hdr_int(content_length, buf->len);
 160         hdr_str(content_type, type);
 161         end_headers();
 162         write_or_die(1, buf->buf, buf->len);
 163 }
 164
 165 static void send_local_file(const char *the_type, const char *name)
 166 {
 167         const char *p = git_path("%s", name);
 168         size_t buf_alloc = 8192;
 169         char *buf = xmalloc(buf_alloc);
 170         int fd;
 171         struct stat sb;
 172
 173         fd = open(p, O_RDONLY);
 174         if (fd < 0)
 175                 not_found("Cannot open '%s': %s", p, strerror(errno));
 176         if (fstat(fd, &sb) < 0)
 177                 die_errno("Cannot stat '%s'", p);
 178
 179         hdr_int(content_length, sb.st_size);
 180         hdr_str(content_type, the_type);
 181         hdr_date(last_modified, sb.st_mtime);
 182         end_headers();
 183
 184         for (;;) {
 185                 ssize_t n = xread(fd, buf, buf_alloc);
 186                 if (n < 0)
 187                         die_errno("Cannot read '%s'", p);
 188                 if (!n)
 189                         break;
 190                 write_or_die(1, buf, n);
 191         }
 192         close(fd);
 193         free(buf);
 194 }
 195
 196 static void get_text_file(char *name)
 197 {
 198         select_getanyfile();
 199         hdr_nocache();
 200         send_local_file("text/plain", name);
 201 }
 202
 203 static void get_loose_object(char *name)
 204 {
 205         select_getanyfile();
 206         hdr_cache_forever();
 207         send_local_file("application/x-git-loose-object", name);
 208 }
 209
 210 static void get_pack_file(char *name)
 211 {
 212         select_getanyfile();
 213         hdr_cache_forever();
 214         send_local_file("application/x-git-packed-objects", name);
 215 }
 216
 217 static void get_idx_file(char *name)
 218 {
 219         select_getanyfile();
 220         hdr_cache_forever();
 221         send_local_file("application/x-git-packed-objects-toc", name);
 222 }
 223
 224 static void http_config(void)
 225 {
 226         int i, value = 0;
 227         struct strbuf var = STRBUF_INIT;
 228
 229         git_config_get_bool("http.getanyfile", &getanyfile);
 230         git_config_get_ulong("http.maxrequestbuffer", &max_request_buffer);
 231
 232         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 233                 struct rpc_service *svc = &rpc_service[i];
 234                 strbuf_addf(&var, "http.%s", svc->config_name);
 235                 if (!git_config_get_bool(var.buf, &value))
 236                         svc->enabled = value;
 237                 strbuf_reset(&var);
 238         }
 239
 240         strbuf_release(&var);
 241 }
 242
 243 static struct rpc_service *select_service(const char *name)
 244 {
 245         const char *svc_name;
 246         struct rpc_service *svc = NULL;
 247         int i;
 248
 249         if (!skip_prefix(name, "git-", &svc_name))
 250                 forbidden("Unsupported service: '%s'", name);
 251
 252         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 253                 struct rpc_service *s = &rpc_service[i];
 254                 if (!strcmp(s->name, svc_name)) {
 255                         svc = s;
 256                         break;
 257                 }
 258         }
 259
 260         if (!svc)
 261                 forbidden("Unsupported service: '%s'", name);
 262
 263         if (svc->enabled < 0) {
 264                 const char *user = getenv("REMOTE_USER");
 265                 svc->enabled = (user && *user) ? 1 : 0;
 266         }
 267         if (!svc->enabled)
 268                 forbidden("Service not enabled: '%s'", svc->name);
 269         return svc;
 270 }
 271
 272 /*
 273  * This is basically strbuf_read(), except that if we
 274  * hit max_request_buffer we die (we'd rather reject a
 275  * maliciously large request than chew up infinite memory).
 276  */
 277 static ssize_t read_request(int fd, unsigned char **out)
 278 {
 279         size_t len = 0, alloc = 8192;
 280         unsigned char *buf = xmalloc(alloc);
 281
 282         if (max_request_buffer < alloc)
 283                 max_request_buffer = alloc;
 284
 285         while (1) {
 286                 ssize_t cnt;
 287
 288                 cnt = read_in_full(fd, buf + len, alloc - len);
 289                 if (cnt < 0) {
 290                         free(buf);
 291                         return -1;
 292                 }
 293
 294                 /* partial read from read_in_full means we hit EOF */
 295                 len += cnt;
 296                 if (len < alloc) {
 297                         *out = buf;
 298                         return len;
 299                 }
 300
 301                 /* otherwise, grow and try again (if we can) */
 302                 if (alloc == max_request_buffer)
 303                         die("request was larger than our maximum size (%lu);"
 304                             " try setting GIT_HTTP_MAX_REQUEST_BUFFER",
 305                             max_request_buffer);
 306
 307                 alloc = alloc_nr(alloc);
 308                 if (alloc > max_request_buffer)
 309                         alloc = max_request_buffer;
 310                 REALLOC_ARRAY(buf, alloc);
 311         }
 312 }
 313
 314 static void inflate_request(const char *prog_name, int out, int buffer_input)
 315 {
 316         git_zstream stream;
 317         unsigned char *full_request = NULL;
 318         unsigned char in_buf[8192];
 319         unsigned char out_buf[8192];
 320         unsigned long cnt = 0;
 321
 322         memset(&stream, 0, sizeof(stream));
 323         git_inflate_init_gzip_only(&stream);
 324
 325         while (1) {
 326                 ssize_t n;
 327
 328                 if (buffer_input) {
 329                         if (full_request)
 330                                 n = 0; /* nothing left to read */
 331                         else
 332                                 n = read_request(0, &full_request);
 333                         stream.next_in = full_request;
 334                 } else {
 335                         n = xread(0, in_buf, sizeof(in_buf));
 336                         stream.next_in = in_buf;
 337                 }
 338
 339                 if (n <= 0)
 340                         die("request ended in the middle of the gzip stream");
 341                 stream.avail_in = n;
 342
 343                 while (0 < stream.avail_in) {
 344                         int ret;
 345
 346                         stream.next_out = out_buf;
 347                         stream.avail_out = sizeof(out_buf);
 348
 349                         ret = git_inflate(&stream, Z_NO_FLUSH);
 350                         if (ret != Z_OK && ret != Z_STREAM_END)
 351                                 die("zlib error inflating request, result %d", ret);
 352
 353                         n = stream.total_out - cnt;
 354                         if (write_in_full(out, out_buf, n) != n)
 355                                 die("%s aborted reading request", prog_name);
 356                         cnt += n;
 357
 358                         if (ret == Z_STREAM_END)
 359                                 goto done;
 360                 }
 361         }
 362
 363 done:
 364         git_inflate_end(&stream);
 365         close(out);
 366         free(full_request);
 367 }
 368
 369 static void copy_request(const char *prog_name, int out)
 370 {
 371         unsigned char *buf;
 372         ssize_t n = read_request(0, &buf);
 373         if (n < 0)
 374                 die_errno("error reading request body");
 375         if (write_in_full(out, buf, n) != n)
 376                 die("%s aborted reading request", prog_name);
 377         close(out);
 378         free(buf);
 379 }
 380
 381 static void run_service(const char **argv, int buffer_input)
 382 {
 383         const char *encoding = getenv("HTTP_CONTENT_ENCODING");
 384         const char *user = getenv("REMOTE_USER");
 385         const char *host = getenv("REMOTE_ADDR");
 386         int gzipped_request = 0;
 387         struct child_process cld = CHILD_PROCESS_INIT;
 388
 389         if (encoding && !strcmp(encoding, "gzip"))
 390                 gzipped_request = 1;
 391         else if (encoding && !strcmp(encoding, "x-gzip"))
 392                 gzipped_request = 1;
 393
 394         if (!user || !*user)
 395                 user = "anonymous";
 396         if (!host || !*host)
 397                 host = "(none)";
 398
 399         if (!getenv("GIT_COMMITTER_NAME"))
 400                 argv_array_pushf(&cld.env_array, "GIT_COMMITTER_NAME=%s", user);
 401         if (!getenv("GIT_COMMITTER_EMAIL"))
 402                 argv_array_pushf(&cld.env_array,
 403                                  "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
 404
 405         cld.argv = argv;
 406         if (buffer_input || gzipped_request)
 407                 cld.in = -1;
 408         cld.git_cmd = 1;
 409         if (start_command(&cld))
 410                 exit(1);
 411
 412         close(1);
 413         if (gzipped_request)
 414                 inflate_request(argv[0], cld.in, buffer_input);
 415         else if (buffer_input)
 416                 copy_request(argv[0], cld.in);
 417         else
 418                 close(0);
 419
 420         if (finish_command(&cld))
 421                 exit(1);
 422 }
 423
 424 static int show_text_ref(const char *name, const unsigned char *sha1,
 425         int flag, void *cb_data)
 426 {
 427         const char *name_nons = strip_namespace(name);
 428         struct strbuf *buf = cb_data;
 429         struct object *o = parse_object(sha1);
 430         if (!o)
 431                 return 0;
 432
 433         strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name_nons);
 434         if (o->type == OBJ_TAG) {
 435                 o = deref_tag(o, name, 0);
 436                 if (!o)
 437                         return 0;
 438                 strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1),
 439                             name_nons);
 440         }
 441         return 0;
 442 }
 443
 444 static void get_info_refs(char *arg)
 445 {
 446         const char *service_name = get_parameter("service");
 447         struct strbuf buf = STRBUF_INIT;
 448
 449         hdr_nocache();
 450
 451         if (service_name) {
 452                 const char *argv[] = {NULL /* service name */,
 453                         "--stateless-rpc", "--advertise-refs",
 454                         ".", NULL};
 455                 struct rpc_service *svc = select_service(service_name);
 456
 457                 strbuf_addf(&buf, "application/x-git-%s-advertisement",
 458                         svc->name);
 459                 hdr_str(content_type, buf.buf);
 460                 end_headers();
 461
 462                 packet_write(1, "# service=git-%s\n", svc->name);
 463                 packet_flush(1);
 464
 465                 argv[0] = svc->name;
 466                 run_service(argv, 0);
 467
 468         } else {
 469                 select_getanyfile();
 470                 for_each_namespaced_ref(show_text_ref, &buf);
 471                 send_strbuf("text/plain", &buf);
 472         }
 473         strbuf_release(&buf);
 474 }
 475
 476 static int show_head_ref(const char *refname, const unsigned char *sha1,
 477         int flag, void *cb_data)
 478 {
 479         struct strbuf *buf = cb_data;
 480
 481         if (flag & REF_ISSYMREF) {
 482                 unsigned char unused[20];
 483                 const char *target = resolve_ref_unsafe(refname,
 484                                                         RESOLVE_REF_READING,
 485                                                         unused, NULL);
 486                 const char *target_nons = strip_namespace(target);
 487
 488                 strbuf_addf(buf, "ref: %s\n", target_nons);
 489         } else {
 490                 strbuf_addf(buf, "%s\n", sha1_to_hex(sha1));
 491         }
 492
 493         return 0;
 494 }
 495
 496 static void get_head(char *arg)
 497 {
 498         struct strbuf buf = STRBUF_INIT;
 499
 500         select_getanyfile();
 501         head_ref_namespaced(show_head_ref, &buf);
 502         send_strbuf("text/plain", &buf);
 503         strbuf_release(&buf);
 504 }
 505
 506 static void get_info_packs(char *arg)
 507 {
 508         size_t objdirlen = strlen(get_object_directory());
 509         struct strbuf buf = STRBUF_INIT;
 510         struct packed_git *p;
 511         size_t cnt = 0;
 512
 513         select_getanyfile();
 514         prepare_packed_git();
 515         for (p = packed_git; p; p = p->next) {
 516                 if (p->pack_local)
 517                         cnt++;
 518         }
 519
 520         strbuf_grow(&buf, cnt * 53 + 2);
 521         for (p = packed_git; p; p = p->next) {
 522                 if (p->pack_local)
 523                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
 524         }
 525         strbuf_addch(&buf, '\n');
 526
 527         hdr_nocache();
 528         send_strbuf("text/plain; charset=utf-8", &buf);
 529         strbuf_release(&buf);
 530 }
 531
 532 static void check_content_type(const char *accepted_type)
 533 {
 534         const char *actual_type = getenv("CONTENT_TYPE");
 535
 536         if (!actual_type)
 537                 actual_type = "";
 538
 539         if (strcmp(actual_type, accepted_type)) {
 540                 http_status(415, "Unsupported Media Type");
 541                 hdr_nocache();
 542                 end_headers();
 543                 format_write(1,
 544                         "Expected POST with Content-Type '%s',"
 545                         " but received '%s' instead.\n",
 546                         accepted_type, actual_type);
 547                 exit(0);
 548         }
 549 }
 550
 551 static void service_rpc(char *service_name)
 552 {
 553         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
 554         struct rpc_service *svc = select_service(service_name);
 555         struct strbuf buf = STRBUF_INIT;
 556
 557         strbuf_reset(&buf);
 558         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
 559         check_content_type(buf.buf);
 560
 561         hdr_nocache();
 562
 563         strbuf_reset(&buf);
 564         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
 565         hdr_str(content_type, buf.buf);
 566
 567         end_headers();
 568
 569         argv[0] = svc->name;
 570         run_service(argv, svc->buffer_input);
 571         strbuf_release(&buf);
 572 }
 573
 574 static int dead;
 575 static NORETURN void die_webcgi(const char *err, va_list params)
 576 {
 577         if (dead <= 1) {
 578                 vreportf("fatal: ", err, params);
 579
 580                 http_status(500, "Internal Server Error");
 581                 hdr_nocache();
 582                 end_headers();
 583         }
 584         exit(0); /* we successfully reported a failure ;-) */
 585 }
 586
 587 static int die_webcgi_recursing(void)
 588 {
 589         return dead++ > 1;
 590 }
 591
 592 static char* getdir(void)
 593 {
 594         struct strbuf buf = STRBUF_INIT;
 595         char *pathinfo = getenv("PATH_INFO");
 596         char *root = getenv("GIT_PROJECT_ROOT");
 597         char *path = getenv("PATH_TRANSLATED");
 598
 599         if (root && *root) {
 600                 if (!pathinfo || !*pathinfo)
 601                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
 602                 if (daemon_avoid_alias(pathinfo))
 603                         die("'%s': aliased", pathinfo);
 604                 end_url_with_slash(&buf, root);
 605                 if (pathinfo[0] == '/')
 606                         pathinfo++;
 607                 strbuf_addstr(&buf, pathinfo);
 608                 return strbuf_detach(&buf, NULL);
 609         } else if (path && *path) {
 610                 return xstrdup(path);
 611         } else
 612                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
 613         return NULL;
 614 }
 615
 616 static struct service_cmd {
 617         const char *method;
 618         const char *pattern;
 619         void (*imp)(char *);
 620 } services[] = {
 621         {"GET", "/HEAD$", get_head},
 622         {"GET", "/info/refs$", get_info_refs},
 623         {"GET", "/objects/info/alternates$", get_text_file},
 624         {"GET", "/objects/info/http-alternates$", get_text_file},
 625         {"GET", "/objects/info/packs$", get_info_packs},
 626         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
 627         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
 628         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
 629
 630         {"POST", "/git-upload-pack$", service_rpc},
 631         {"POST", "/git-receive-pack$", service_rpc}
 632 };
 633
 634 int main(int argc, char **argv)
 635 {
 636         char *method = getenv("REQUEST_METHOD");
 637         char *dir;
 638         struct service_cmd *cmd = NULL;
 639         char *cmd_arg = NULL;
 640         int i;
 641
 642         git_setup_gettext();
 643
 644         git_extract_argv0_path(argv[0]);
 645         set_die_routine(die_webcgi);
 646         set_die_is_recursing_routine(die_webcgi_recursing);
 647
 648         if (!method)
 649                 die("No REQUEST_METHOD from server");
 650         if (!strcmp(method, "HEAD"))
 651                 method = "GET";
 652         dir = getdir();
 653
 654         for (i = 0; i < ARRAY_SIZE(services); i++) {
 655                 struct service_cmd *c = &services[i];
 656                 regex_t re;
 657                 regmatch_t out[1];
 658
 659                 if (regcomp(&re, c->pattern, REG_EXTENDED))
 660                         die("Bogus regex in service table: %s", c->pattern);
 661                 if (!regexec(&re, dir, 1, out, 0)) {
 662                         size_t n;
 663
 664                         if (strcmp(method, c->method)) {
 665                                 const char *proto = getenv("SERVER_PROTOCOL");
 666                                 if (proto && !strcmp(proto, "HTTP/1.1")) {
 667                                         http_status(405, "Method Not Allowed");
 668                                         hdr_str("Allow", !strcmp(c->method, "GET") ?
 669                                                 "GET, HEAD" : c->method);
 670                                 } else
 671                                         http_status(400, "Bad Request");
 672                                 hdr_nocache();
 673                                 end_headers();
 674                                 return 0;
 675                         }
 676
 677                         cmd = c;
 678                         n = out[0].rm_eo - out[0].rm_so;
 679                         cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
 680                         dir[out[0].rm_so] = 0;
 681                         break;
 682                 }
 683                 regfree(&re);
 684         }
 685
 686         if (!cmd)
 687                 not_found("Request not supported: '%s'", dir);
 688
 689         setup_path();
 690         if (!enter_repo(dir, 0))
 691                 not_found("Not a git repository: '%s'", dir);
 692         if (!getenv("GIT_HTTP_EXPORT_ALL") &&
 693             access("git-daemon-export-ok", F_OK) )
 694                 not_found("Repository not exported: '%s'", dir);
 695
 696         http_config();
 697         max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER",
 698                                            max_request_buffer);
 699
 700         cmd->imp(cmd_arg);
 701         return 0;
 702 }