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_MODE(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         char *p = git_pathdup("%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         free(p);
 195 }
 196
 197 static void get_text_file(char *name)
 198 {
 199         select_getanyfile();
 200         hdr_nocache();
 201         send_local_file("text/plain", name);
 202 }
 203
 204 static void get_loose_object(char *name)
 205 {
 206         select_getanyfile();
 207         hdr_cache_forever();
 208         send_local_file("application/x-git-loose-object", name);
 209 }
 210
 211 static void get_pack_file(char *name)
 212 {
 213         select_getanyfile();
 214         hdr_cache_forever();
 215         send_local_file("application/x-git-packed-objects", name);
 216 }
 217
 218 static void get_idx_file(char *name)
 219 {
 220         select_getanyfile();
 221         hdr_cache_forever();
 222         send_local_file("application/x-git-packed-objects-toc", name);
 223 }
 224
 225 static void http_config(void)
 226 {
 227         int i, value = 0;
 228         struct strbuf var = STRBUF_INIT;
 229
 230         git_config_get_bool("http.getanyfile", &getanyfile);
 231         git_config_get_ulong("http.maxrequestbuffer", &max_request_buffer);
 232
 233         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 234                 struct rpc_service *svc = &rpc_service[i];
 235                 strbuf_addf(&var, "http.%s", svc->config_name);
 236                 if (!git_config_get_bool(var.buf, &value))
 237                         svc->enabled = value;
 238                 strbuf_reset(&var);
 239         }
 240
 241         strbuf_release(&var);
 242 }
 243
 244 static struct rpc_service *select_service(const char *name)
 245 {
 246         const char *svc_name;
 247         struct rpc_service *svc = NULL;
 248         int i;
 249
 250         if (!skip_prefix(name, "git-", &svc_name))
 251                 forbidden("Unsupported service: '%s'", name);
 252
 253         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 254                 struct rpc_service *s = &rpc_service[i];
 255                 if (!strcmp(s->name, svc_name)) {
 256                         svc = s;
 257                         break;
 258                 }
 259         }
 260
 261         if (!svc)
 262                 forbidden("Unsupported service: '%s'", name);
 263
 264         if (svc->enabled < 0) {
 265                 const char *user = getenv("REMOTE_USER");
 266                 svc->enabled = (user && *user) ? 1 : 0;
 267         }
 268         if (!svc->enabled)
 269                 forbidden("Service not enabled: '%s'", svc->name);
 270         return svc;
 271 }
 272
 273 /*
 274  * This is basically strbuf_read(), except that if we
 275  * hit max_request_buffer we die (we'd rather reject a
 276  * maliciously large request than chew up infinite memory).
 277  */
 278 static ssize_t read_request(int fd, unsigned char **out)
 279 {
 280         size_t len = 0, alloc = 8192;
 281         unsigned char *buf = xmalloc(alloc);
 282
 283         if (max_request_buffer < alloc)
 284                 max_request_buffer = alloc;
 285
 286         while (1) {
 287                 ssize_t cnt;
 288
 289                 cnt = read_in_full(fd, buf + len, alloc - len);
 290                 if (cnt < 0) {
 291                         free(buf);
 292                         return -1;
 293                 }
 294
 295                 /* partial read from read_in_full means we hit EOF */
 296                 len += cnt;
 297                 if (len < alloc) {
 298                         *out = buf;
 299                         return len;
 300                 }
 301
 302                 /* otherwise, grow and try again (if we can) */
 303                 if (alloc == max_request_buffer)
 304                         die("request was larger than our maximum size (%lu);"
 305                             " try setting GIT_HTTP_MAX_REQUEST_BUFFER",
 306                             max_request_buffer);
 307
 308                 alloc = alloc_nr(alloc);
 309                 if (alloc > max_request_buffer)
 310                         alloc = max_request_buffer;
 311                 REALLOC_ARRAY(buf, alloc);
 312         }
 313 }
 314
 315 static void inflate_request(const char *prog_name, int out, int buffer_input)
 316 {
 317         git_zstream stream;
 318         unsigned char *full_request = NULL;
 319         unsigned char in_buf[8192];
 320         unsigned char out_buf[8192];
 321         unsigned long cnt = 0;
 322
 323         memset(&stream, 0, sizeof(stream));
 324         git_inflate_init_gzip_only(&stream);
 325
 326         while (1) {
 327                 ssize_t n;
 328
 329                 if (buffer_input) {
 330                         if (full_request)
 331                                 n = 0; /* nothing left to read */
 332                         else
 333                                 n = read_request(0, &full_request);
 334                         stream.next_in = full_request;
 335                 } else {
 336                         n = xread(0, in_buf, sizeof(in_buf));
 337                         stream.next_in = in_buf;
 338                 }
 339
 340                 if (n <= 0)
 341                         die("request ended in the middle of the gzip stream");
 342                 stream.avail_in = n;
 343
 344                 while (0 < stream.avail_in) {
 345                         int ret;
 346
 347                         stream.next_out = out_buf;
 348                         stream.avail_out = sizeof(out_buf);
 349
 350                         ret = git_inflate(&stream, Z_NO_FLUSH);
 351                         if (ret != Z_OK && ret != Z_STREAM_END)
 352                                 die("zlib error inflating request, result %d", ret);
 353
 354                         n = stream.total_out - cnt;
 355                         if (write_in_full(out, out_buf, n) != n)
 356                                 die("%s aborted reading request", prog_name);
 357                         cnt += n;
 358
 359                         if (ret == Z_STREAM_END)
 360                                 goto done;
 361                 }
 362         }
 363
 364 done:
 365         git_inflate_end(&stream);
 366         close(out);
 367         free(full_request);
 368 }
 369
 370 static void copy_request(const char *prog_name, int out)
 371 {
 372         unsigned char *buf;
 373         ssize_t n = read_request(0, &buf);
 374         if (n < 0)
 375                 die_errno("error reading request body");
 376         if (write_in_full(out, buf, n) != n)
 377                 die("%s aborted reading request", prog_name);
 378         close(out);
 379         free(buf);
 380 }
 381
 382 static void run_service(const char **argv, int buffer_input)
 383 {
 384         const char *encoding = getenv("HTTP_CONTENT_ENCODING");
 385         const char *user = getenv("REMOTE_USER");
 386         const char *host = getenv("REMOTE_ADDR");
 387         int gzipped_request = 0;
 388         struct child_process cld = CHILD_PROCESS_INIT;
 389
 390         if (encoding && !strcmp(encoding, "gzip"))
 391                 gzipped_request = 1;
 392         else if (encoding && !strcmp(encoding, "x-gzip"))
 393                 gzipped_request = 1;
 394
 395         if (!user || !*user)
 396                 user = "anonymous";
 397         if (!host || !*host)
 398                 host = "(none)";
 399
 400         if (!getenv("GIT_COMMITTER_NAME"))
 401                 argv_array_pushf(&cld.env_array, "GIT_COMMITTER_NAME=%s", user);
 402         if (!getenv("GIT_COMMITTER_EMAIL"))
 403                 argv_array_pushf(&cld.env_array,
 404                                  "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
 405
 406         cld.argv = argv;
 407         if (buffer_input || gzipped_request)
 408                 cld.in = -1;
 409         cld.git_cmd = 1;
 410         if (start_command(&cld))
 411                 exit(1);
 412
 413         close(1);
 414         if (gzipped_request)
 415                 inflate_request(argv[0], cld.in, buffer_input);
 416         else if (buffer_input)
 417                 copy_request(argv[0], cld.in);
 418         else
 419                 close(0);
 420
 421         if (finish_command(&cld))
 422                 exit(1);
 423 }
 424
 425 static int show_text_ref(const char *name, const struct object_id *oid,
 426                          int flag, void *cb_data)
 427 {
 428         const char *name_nons = strip_namespace(name);
 429         struct strbuf *buf = cb_data;
 430         struct object *o = parse_object(oid->hash);
 431         if (!o)
 432                 return 0;
 433
 434         strbuf_addf(buf, "%s\t%s\n", oid_to_hex(oid), name_nons);
 435         if (o->type == OBJ_TAG) {
 436                 o = deref_tag(o, name, 0);
 437                 if (!o)
 438                         return 0;
 439                 strbuf_addf(buf, "%s\t%s^{}\n", oid_to_hex(&o->oid),
 440                             name_nons);
 441         }
 442         return 0;
 443 }
 444
 445 static void get_info_refs(char *arg)
 446 {
 447         const char *service_name = get_parameter("service");
 448         struct strbuf buf = STRBUF_INIT;
 449
 450         hdr_nocache();
 451
 452         if (service_name) {
 453                 const char *argv[] = {NULL /* service name */,
 454                         "--stateless-rpc", "--advertise-refs",
 455                         ".", NULL};
 456                 struct rpc_service *svc = select_service(service_name);
 457
 458                 strbuf_addf(&buf, "application/x-git-%s-advertisement",
 459                         svc->name);
 460                 hdr_str(content_type, buf.buf);
 461                 end_headers();
 462
 463                 packet_write(1, "# service=git-%s\n", svc->name);
 464                 packet_flush(1);
 465
 466                 argv[0] = svc->name;
 467                 run_service(argv, 0);
 468
 469         } else {
 470                 select_getanyfile();
 471                 for_each_namespaced_ref(show_text_ref, &buf);
 472                 send_strbuf("text/plain", &buf);
 473         }
 474         strbuf_release(&buf);
 475 }
 476
 477 static int show_head_ref(const char *refname, const struct object_id *oid,
 478                          int flag, void *cb_data)
 479 {
 480         struct strbuf *buf = cb_data;
 481
 482         if (flag & REF_ISSYMREF) {
 483                 struct object_id unused;
 484                 const char *target = resolve_ref_unsafe(refname,
 485                                                         RESOLVE_REF_READING,
 486                                                         unused.hash, NULL);
 487
 488                 if (target)
 489                         strbuf_addf(buf, "ref: %s\n", strip_namespace(target));
 490         } else {
 491                 strbuf_addf(buf, "%s\n", oid_to_hex(oid));
 492         }
 493
 494         return 0;
 495 }
 496
 497 static void get_head(char *arg)
 498 {
 499         struct strbuf buf = STRBUF_INIT;
 500
 501         select_getanyfile();
 502         head_ref_namespaced(show_head_ref, &buf);
 503         send_strbuf("text/plain", &buf);
 504         strbuf_release(&buf);
 505 }
 506
 507 static void get_info_packs(char *arg)
 508 {
 509         size_t objdirlen = strlen(get_object_directory());
 510         struct strbuf buf = STRBUF_INIT;
 511         struct packed_git *p;
 512         size_t cnt = 0;
 513
 514         select_getanyfile();
 515         prepare_packed_git();
 516         for (p = packed_git; p; p = p->next) {
 517                 if (p->pack_local)
 518                         cnt++;
 519         }
 520
 521         strbuf_grow(&buf, cnt * 53 + 2);
 522         for (p = packed_git; p; p = p->next) {
 523                 if (p->pack_local)
 524                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
 525         }
 526         strbuf_addch(&buf, '\n');
 527
 528         hdr_nocache();
 529         send_strbuf("text/plain; charset=utf-8", &buf);
 530         strbuf_release(&buf);
 531 }
 532
 533 static void check_content_type(const char *accepted_type)
 534 {
 535         const char *actual_type = getenv("CONTENT_TYPE");
 536
 537         if (!actual_type)
 538                 actual_type = "";
 539
 540         if (strcmp(actual_type, accepted_type)) {
 541                 http_status(415, "Unsupported Media Type");
 542                 hdr_nocache();
 543                 end_headers();
 544                 format_write(1,
 545                         "Expected POST with Content-Type '%s',"
 546                         " but received '%s' instead.\n",
 547                         accepted_type, actual_type);
 548                 exit(0);
 549         }
 550 }
 551
 552 static void service_rpc(char *service_name)
 553 {
 554         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
 555         struct rpc_service *svc = select_service(service_name);
 556         struct strbuf buf = STRBUF_INIT;
 557
 558         strbuf_reset(&buf);
 559         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
 560         check_content_type(buf.buf);
 561
 562         hdr_nocache();
 563
 564         strbuf_reset(&buf);
 565         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
 566         hdr_str(content_type, buf.buf);
 567
 568         end_headers();
 569
 570         argv[0] = svc->name;
 571         run_service(argv, svc->buffer_input);
 572         strbuf_release(&buf);
 573 }
 574
 575 static int dead;
 576 static NORETURN void die_webcgi(const char *err, va_list params)
 577 {
 578         if (dead <= 1) {
 579                 vreportf("fatal: ", err, params);
 580
 581                 http_status(500, "Internal Server Error");
 582                 hdr_nocache();
 583                 end_headers();
 584         }
 585         exit(0); /* we successfully reported a failure ;-) */
 586 }
 587
 588 static int die_webcgi_recursing(void)
 589 {
 590         return dead++ > 1;
 591 }
 592
 593 static char* getdir(void)
 594 {
 595         struct strbuf buf = STRBUF_INIT;
 596         char *pathinfo = getenv("PATH_INFO");
 597         char *root = getenv("GIT_PROJECT_ROOT");
 598         char *path = getenv("PATH_TRANSLATED");
 599
 600         if (root && *root) {
 601                 if (!pathinfo || !*pathinfo)
 602                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
 603                 if (daemon_avoid_alias(pathinfo))
 604                         die("'%s': aliased", pathinfo);
 605                 end_url_with_slash(&buf, root);
 606                 if (pathinfo[0] == '/')
 607                         pathinfo++;
 608                 strbuf_addstr(&buf, pathinfo);
 609                 return strbuf_detach(&buf, NULL);
 610         } else if (path && *path) {
 611                 return xstrdup(path);
 612         } else
 613                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
 614         return NULL;
 615 }
 616
 617 static struct service_cmd {
 618         const char *method;
 619         const char *pattern;
 620         void (*imp)(char *);
 621 } services[] = {
 622         {"GET", "/HEAD$", get_head},
 623         {"GET", "/info/refs$", get_info_refs},
 624         {"GET", "/objects/info/alternates$", get_text_file},
 625         {"GET", "/objects/info/http-alternates$", get_text_file},
 626         {"GET", "/objects/info/packs$", get_info_packs},
 627         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
 628         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
 629         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
 630
 631         {"POST", "/git-upload-pack$", service_rpc},
 632         {"POST", "/git-receive-pack$", service_rpc}
 633 };
 634
 635 int cmd_main(int argc, const char **argv)
 636 {
 637         char *method = getenv("REQUEST_METHOD");
 638         char *dir;
 639         struct service_cmd *cmd = NULL;
 640         char *cmd_arg = NULL;
 641         int i;
 642
 643         set_die_routine(die_webcgi);
 644         set_die_is_recursing_routine(die_webcgi_recursing);
 645
 646         if (!method)
 647                 die("No REQUEST_METHOD from server");
 648         if (!strcmp(method, "HEAD"))
 649                 method = "GET";
 650         dir = getdir();
 651
 652         for (i = 0; i < ARRAY_SIZE(services); i++) {
 653                 struct service_cmd *c = &services[i];
 654                 regex_t re;
 655                 regmatch_t out[1];
 656
 657                 if (regcomp(&re, c->pattern, REG_EXTENDED))
 658                         die("Bogus regex in service table: %s", c->pattern);
 659                 if (!regexec(&re, dir, 1, out, 0)) {
 660                         size_t n;
 661
 662                         if (strcmp(method, c->method)) {
 663                                 const char *proto = getenv("SERVER_PROTOCOL");
 664                                 if (proto && !strcmp(proto, "HTTP/1.1")) {
 665                                         http_status(405, "Method Not Allowed");
 666                                         hdr_str("Allow", !strcmp(c->method, "GET") ?
 667                                                 "GET, HEAD" : c->method);
 668                                 } else
 669                                         http_status(400, "Bad Request");
 670                                 hdr_nocache();
 671                                 end_headers();
 672                                 return 0;
 673                         }
 674
 675                         cmd = c;
 676                         n = out[0].rm_eo - out[0].rm_so;
 677                         cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
 678                         dir[out[0].rm_so] = 0;
 679                         break;
 680                 }
 681                 regfree(&re);
 682         }
 683
 684         if (!cmd)
 685                 not_found("Request not supported: '%s'", dir);
 686
 687         setup_path();
 688         if (!enter_repo(dir, 0))
 689                 not_found("Not a git repository: '%s'", dir);
 690         if (!getenv("GIT_HTTP_EXPORT_ALL") &&
 691             access("git-daemon-export-ok", F_OK) )
 692                 not_found("Repository not exported: '%s'", dir);
 693
 694         http_config();
 695         max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER",
 696                                            max_request_buffer);
 697
 698         cmd->imp(cmd_arg);
 699         return 0;
 700 }