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
  10 static const char content_type[] = "Content-Type";
  11 static const char content_length[] = "Content-Length";
  12 static const char last_modified[] = "Last-Modified";
  13 static int getanyfile = 1;
  14
  15 static struct string_list *query_params;
  16
  17 struct rpc_service {
  18         const char *name;
  19         const char *config_name;
  20         signed enabled : 2;
  21 };
  22
  23 static struct rpc_service rpc_service[] = {
  24         { "upload-pack", "uploadpack", 1 },
  25         { "receive-pack", "receivepack", -1 },
  26 };
  27
  28 static int decode_char(const char *q)
  29 {
  30         int i;
  31         unsigned char val = 0;
  32         for (i = 0; i < 2; i++) {
  33                 unsigned char c = *q++;
  34                 val <<= 4;
  35                 if (c >= '0' && c <= '9')
  36                         val += c - '0';
  37                 else if (c >= 'a' && c <= 'f')
  38                         val += c - 'a' + 10;
  39                 else if (c >= 'A' && c <= 'F')
  40                         val += c - 'A' + 10;
  41                 else
  42                         return -1;
  43         }
  44         return val;
  45 }
  46
  47 static char *decode_parameter(const char **query, int is_name)
  48 {
  49         const char *q = *query;
  50         struct strbuf out;
  51
  52         strbuf_init(&out, 16);
  53         do {
  54                 unsigned char c = *q;
  55
  56                 if (!c)
  57                         break;
  58                 if (c == '&' || (is_name && c == '=')) {
  59                         q++;
  60                         break;
  61                 }
  62
  63                 if (c == '%') {
  64                         int val = decode_char(q + 1);
  65                         if (0 <= val) {
  66                                 strbuf_addch(&out, val);
  67                                 q += 3;
  68                                 continue;
  69                         }
  70                 }
  71
  72                 if (c == '+')
  73                         strbuf_addch(&out, ' ');
  74                 else
  75                         strbuf_addch(&out, c);
  76                 q++;
  77         } while (1);
  78         *query = q;
  79         return strbuf_detach(&out, NULL);
  80 }
  81
  82 static struct string_list *get_parameters(void)
  83 {
  84         if (!query_params) {
  85                 const char *query = getenv("QUERY_STRING");
  86
  87                 query_params = xcalloc(1, sizeof(*query_params));
  88                 while (query && *query) {
  89                         char *name = decode_parameter(&query, 1);
  90                         char *value = decode_parameter(&query, 0);
  91                         struct string_list_item *i;
  92
  93                         i = string_list_lookup(name, query_params);
  94                         if (!i)
  95                                 i = string_list_insert(name, query_params);
  96                         else
  97                                 free(i->util);
  98                         i->util = value;
  99                 }
 100         }
 101         return query_params;
 102 }
 103
 104 static const char *get_parameter(const char *name)
 105 {
 106         struct string_list_item *i;
 107         i = string_list_lookup(name, get_parameters());
 108         return i ? i->util : NULL;
 109 }
 110
 111 static void format_write(int fd, const char *fmt, ...)
 112 {
 113         static char buffer[1024];
 114
 115         va_list args;
 116         unsigned n;
 117
 118         va_start(args, fmt);
 119         n = vsnprintf(buffer, sizeof(buffer), fmt, args);
 120         va_end(args);
 121         if (n >= sizeof(buffer))
 122                 die("protocol error: impossibly long line");
 123
 124         safe_write(fd, buffer, n);
 125 }
 126
 127 static void http_status(unsigned code, const char *msg)
 128 {
 129         format_write(1, "Status: %u %s\r\n", code, msg);
 130 }
 131
 132 static void hdr_str(const char *name, const char *value)
 133 {
 134         format_write(1, "%s: %s\r\n", name, value);
 135 }
 136
 137 static void hdr_int(const char *name, uintmax_t value)
 138 {
 139         format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
 140 }
 141
 142 static void hdr_date(const char *name, unsigned long when)
 143 {
 144         const char *value = show_date(when, 0, DATE_RFC2822);
 145         hdr_str(name, value);
 146 }
 147
 148 static void hdr_nocache(void)
 149 {
 150         hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
 151         hdr_str("Pragma", "no-cache");
 152         hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate");
 153 }
 154
 155 static void hdr_cache_forever(void)
 156 {
 157         unsigned long now = time(NULL);
 158         hdr_date("Date", now);
 159         hdr_date("Expires", now + 31536000);
 160         hdr_str("Cache-Control", "public, max-age=31536000");
 161 }
 162
 163 static void end_headers(void)
 164 {
 165         safe_write(1, "\r\n", 2);
 166 }
 167
 168 static NORETURN void not_found(const char *err, ...)
 169 {
 170         va_list params;
 171
 172         http_status(404, "Not Found");
 173         hdr_nocache();
 174         end_headers();
 175
 176         va_start(params, err);
 177         if (err && *err)
 178                 vfprintf(stderr, err, params);
 179         va_end(params);
 180         exit(0);
 181 }
 182
 183 static NORETURN void forbidden(const char *err, ...)
 184 {
 185         va_list params;
 186
 187         http_status(403, "Forbidden");
 188         hdr_nocache();
 189         end_headers();
 190
 191         va_start(params, err);
 192         if (err && *err)
 193                 vfprintf(stderr, err, params);
 194         va_end(params);
 195         exit(0);
 196 }
 197
 198 static void select_getanyfile(void)
 199 {
 200         if (!getanyfile)
 201                 forbidden("Unsupported service: getanyfile");
 202 }
 203
 204 static void send_strbuf(const char *type, struct strbuf *buf)
 205 {
 206         hdr_int(content_length, buf->len);
 207         hdr_str(content_type, type);
 208         end_headers();
 209         safe_write(1, buf->buf, buf->len);
 210 }
 211
 212 static void send_local_file(const char *the_type, const char *name)
 213 {
 214         const char *p = git_path("%s", name);
 215         size_t buf_alloc = 8192;
 216         char *buf = xmalloc(buf_alloc);
 217         int fd;
 218         struct stat sb;
 219
 220         fd = open(p, O_RDONLY);
 221         if (fd < 0)
 222                 not_found("Cannot open '%s': %s", p, strerror(errno));
 223         if (fstat(fd, &sb) < 0)
 224                 die_errno("Cannot stat '%s'", p);
 225
 226         hdr_int(content_length, sb.st_size);
 227         hdr_str(content_type, the_type);
 228         hdr_date(last_modified, sb.st_mtime);
 229         end_headers();
 230
 231         for (;;) {
 232                 ssize_t n = xread(fd, buf, buf_alloc);
 233                 if (n < 0)
 234                         die_errno("Cannot read '%s'", p);
 235                 if (!n)
 236                         break;
 237                 safe_write(1, buf, n);
 238         }
 239         close(fd);
 240         free(buf);
 241 }
 242
 243 static void get_text_file(char *name)
 244 {
 245         select_getanyfile();
 246         hdr_nocache();
 247         send_local_file("text/plain", name);
 248 }
 249
 250 static void get_loose_object(char *name)
 251 {
 252         select_getanyfile();
 253         hdr_cache_forever();
 254         send_local_file("application/x-git-loose-object", name);
 255 }
 256
 257 static void get_pack_file(char *name)
 258 {
 259         select_getanyfile();
 260         hdr_cache_forever();
 261         send_local_file("application/x-git-packed-objects", name);
 262 }
 263
 264 static void get_idx_file(char *name)
 265 {
 266         select_getanyfile();
 267         hdr_cache_forever();
 268         send_local_file("application/x-git-packed-objects-toc", name);
 269 }
 270
 271 static int http_config(const char *var, const char *value, void *cb)
 272 {
 273         if (!strcmp(var, "http.getanyfile")) {
 274                 getanyfile = git_config_bool(var, value);
 275                 return 0;
 276         }
 277
 278         if (!prefixcmp(var, "http.")) {
 279                 int i;
 280
 281                 for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 282                         struct rpc_service *svc = &rpc_service[i];
 283                         if (!strcmp(var + 5, svc->config_name)) {
 284                                 svc->enabled = git_config_bool(var, value);
 285                                 return 0;
 286                         }
 287                 }
 288         }
 289
 290         /* we are not interested in parsing any other configuration here */
 291         return 0;
 292 }
 293
 294 static struct rpc_service *select_service(const char *name)
 295 {
 296         struct rpc_service *svc = NULL;
 297         int i;
 298
 299         if (prefixcmp(name, "git-"))
 300                 forbidden("Unsupported service: '%s'", name);
 301
 302         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 303                 struct rpc_service *s = &rpc_service[i];
 304                 if (!strcmp(s->name, name + 4)) {
 305                         svc = s;
 306                         break;
 307                 }
 308         }
 309
 310         if (!svc)
 311                 forbidden("Unsupported service: '%s'", name);
 312
 313         if (svc->enabled < 0) {
 314                 const char *user = getenv("REMOTE_USER");
 315                 svc->enabled = (user && *user) ? 1 : 0;
 316         }
 317         if (!svc->enabled)
 318                 forbidden("Service not enabled: '%s'", svc->name);
 319         return svc;
 320 }
 321
 322 static void inflate_request(const char *prog_name, int out)
 323 {
 324         z_stream stream;
 325         unsigned char in_buf[8192];
 326         unsigned char out_buf[8192];
 327         unsigned long cnt = 0;
 328         int ret;
 329
 330         memset(&stream, 0, sizeof(stream));
 331         ret = inflateInit2(&stream, (15 + 16));
 332         if (ret != Z_OK)
 333                 die("cannot start zlib inflater, zlib err %d", ret);
 334
 335         while (1) {
 336                 ssize_t n = xread(0, in_buf, sizeof(in_buf));
 337                 if (n <= 0)
 338                         die("request ended in the middle of the gzip stream");
 339
 340                 stream.next_in = in_buf;
 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 = 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         inflateEnd(&stream);
 365         close(out);
 366 }
 367
 368 static void run_service(const char **argv)
 369 {
 370         const char *encoding = getenv("HTTP_CONTENT_ENCODING");
 371         const char *user = getenv("REMOTE_USER");
 372         const char *host = getenv("REMOTE_ADDR");
 373         char *env[3];
 374         struct strbuf buf = STRBUF_INIT;
 375         int gzipped_request = 0;
 376         struct child_process cld;
 377
 378         if (encoding && !strcmp(encoding, "gzip"))
 379                 gzipped_request = 1;
 380         else if (encoding && !strcmp(encoding, "x-gzip"))
 381                 gzipped_request = 1;
 382
 383         if (!user || !*user)
 384                 user = "anonymous";
 385         if (!host || !*host)
 386                 host = "(none)";
 387
 388         memset(&env, 0, sizeof(env));
 389         strbuf_addf(&buf, "GIT_COMMITTER_NAME=%s", user);
 390         env[0] = strbuf_detach(&buf, NULL);
 391
 392         strbuf_addf(&buf, "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
 393         env[1] = strbuf_detach(&buf, NULL);
 394         env[2] = NULL;
 395
 396         memset(&cld, 0, sizeof(cld));
 397         cld.argv = argv;
 398         cld.env = (const char *const *)env;
 399         if (gzipped_request)
 400                 cld.in = -1;
 401         cld.git_cmd = 1;
 402         if (start_command(&cld))
 403                 exit(1);
 404
 405         close(1);
 406         if (gzipped_request)
 407                 inflate_request(argv[0], cld.in);
 408         else
 409                 close(0);
 410
 411         if (finish_command(&cld))
 412                 exit(1);
 413         free(env[0]);
 414         free(env[1]);
 415         strbuf_release(&buf);
 416 }
 417
 418 static int show_text_ref(const char *name, const unsigned char *sha1,
 419         int flag, void *cb_data)
 420 {
 421         struct strbuf *buf = cb_data;
 422         struct object *o = parse_object(sha1);
 423         if (!o)
 424                 return 0;
 425
 426         strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name);
 427         if (o->type == OBJ_TAG) {
 428                 o = deref_tag(o, name, 0);
 429                 if (!o)
 430                         return 0;
 431                 strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1), name);
 432         }
 433         return 0;
 434 }
 435
 436 static void get_info_refs(char *arg)
 437 {
 438         const char *service_name = get_parameter("service");
 439         struct strbuf buf = STRBUF_INIT;
 440
 441         hdr_nocache();
 442
 443         if (service_name) {
 444                 const char *argv[] = {NULL /* service name */,
 445                         "--stateless-rpc", "--advertise-refs",
 446                         ".", NULL};
 447                 struct rpc_service *svc = select_service(service_name);
 448
 449                 strbuf_addf(&buf, "application/x-git-%s-advertisement",
 450                         svc->name);
 451                 hdr_str(content_type, buf.buf);
 452                 end_headers();
 453
 454                 packet_write(1, "# service=git-%s\n", svc->name);
 455                 packet_flush(1);
 456
 457                 argv[0] = svc->name;
 458                 run_service(argv);
 459
 460         } else {
 461                 select_getanyfile();
 462                 for_each_ref(show_text_ref, &buf);
 463                 send_strbuf("text/plain", &buf);
 464         }
 465         strbuf_release(&buf);
 466 }
 467
 468 static void get_info_packs(char *arg)
 469 {
 470         size_t objdirlen = strlen(get_object_directory());
 471         struct strbuf buf = STRBUF_INIT;
 472         struct packed_git *p;
 473         size_t cnt = 0;
 474
 475         select_getanyfile();
 476         prepare_packed_git();
 477         for (p = packed_git; p; p = p->next) {
 478                 if (p->pack_local)
 479                         cnt++;
 480         }
 481
 482         strbuf_grow(&buf, cnt * 53 + 2);
 483         for (p = packed_git; p; p = p->next) {
 484                 if (p->pack_local)
 485                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
 486         }
 487         strbuf_addch(&buf, '\n');
 488
 489         hdr_nocache();
 490         send_strbuf("text/plain; charset=utf-8", &buf);
 491         strbuf_release(&buf);
 492 }
 493
 494 static void check_content_type(const char *accepted_type)
 495 {
 496         const char *actual_type = getenv("CONTENT_TYPE");
 497
 498         if (!actual_type)
 499                 actual_type = "";
 500
 501         if (strcmp(actual_type, accepted_type)) {
 502                 http_status(415, "Unsupported Media Type");
 503                 hdr_nocache();
 504                 end_headers();
 505                 format_write(1,
 506                         "Expected POST with Content-Type '%s',"
 507                         " but received '%s' instead.\n",
 508                         accepted_type, actual_type);
 509                 exit(0);
 510         }
 511 }
 512
 513 static void service_rpc(char *service_name)
 514 {
 515         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
 516         struct rpc_service *svc = select_service(service_name);
 517         struct strbuf buf = STRBUF_INIT;
 518
 519         strbuf_reset(&buf);
 520         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
 521         check_content_type(buf.buf);
 522
 523         hdr_nocache();
 524
 525         strbuf_reset(&buf);
 526         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
 527         hdr_str(content_type, buf.buf);
 528
 529         end_headers();
 530
 531         argv[0] = svc->name;
 532         run_service(argv);
 533         strbuf_release(&buf);
 534 }
 535
 536 static NORETURN void die_webcgi(const char *err, va_list params)
 537 {
 538         char buffer[1000];
 539
 540         http_status(500, "Internal Server Error");
 541         hdr_nocache();
 542         end_headers();
 543
 544         vsnprintf(buffer, sizeof(buffer), err, params);
 545         fprintf(stderr, "fatal: %s\n", buffer);
 546         exit(0);
 547 }
 548
 549 static char* getdir(void)
 550 {
 551         struct strbuf buf = STRBUF_INIT;
 552         char *pathinfo = getenv("PATH_INFO");
 553         char *root = getenv("GIT_PROJECT_ROOT");
 554         char *path = getenv("PATH_TRANSLATED");
 555
 556         if (root && *root) {
 557                 if (!pathinfo || !*pathinfo)
 558                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
 559                 if (daemon_avoid_alias(pathinfo))
 560                         die("'%s': aliased", pathinfo);
 561                 strbuf_addstr(&buf, root);
 562                 if (buf.buf[buf.len - 1] != '/')
 563                         strbuf_addch(&buf, '/');
 564                 if (pathinfo[0] == '/')
 565                         pathinfo++;
 566                 strbuf_addstr(&buf, pathinfo);
 567                 return strbuf_detach(&buf, NULL);
 568         } else if (path && *path) {
 569                 return xstrdup(path);
 570         } else
 571                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
 572         return NULL;
 573 }
 574
 575 static struct service_cmd {
 576         const char *method;
 577         const char *pattern;
 578         void (*imp)(char *);
 579 } services[] = {
 580         {"GET", "/HEAD$", get_text_file},
 581         {"GET", "/info/refs$", get_info_refs},
 582         {"GET", "/objects/info/alternates$", get_text_file},
 583         {"GET", "/objects/info/http-alternates$", get_text_file},
 584         {"GET", "/objects/info/packs$", get_info_packs},
 585         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
 586         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
 587         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
 588
 589         {"POST", "/git-upload-pack$", service_rpc},
 590         {"POST", "/git-receive-pack$", service_rpc}
 591 };
 592
 593 int main(int argc, char **argv)
 594 {
 595         char *method = getenv("REQUEST_METHOD");
 596         char *dir;
 597         struct service_cmd *cmd = NULL;
 598         char *cmd_arg = NULL;
 599         int i;
 600
 601         git_extract_argv0_path(argv[0]);
 602         set_die_routine(die_webcgi);
 603
 604         if (!method)
 605                 die("No REQUEST_METHOD from server");
 606         if (!strcmp(method, "HEAD"))
 607                 method = "GET";
 608         dir = getdir();
 609
 610         for (i = 0; i < ARRAY_SIZE(services); i++) {
 611                 struct service_cmd *c = &services[i];
 612                 regex_t re;
 613                 regmatch_t out[1];
 614
 615                 if (regcomp(&re, c->pattern, REG_EXTENDED))
 616                         die("Bogus regex in service table: %s", c->pattern);
 617                 if (!regexec(&re, dir, 1, out, 0)) {
 618                         size_t n = out[0].rm_eo - out[0].rm_so;
 619
 620                         if (strcmp(method, c->method)) {
 621                                 const char *proto = getenv("SERVER_PROTOCOL");
 622                                 if (proto && !strcmp(proto, "HTTP/1.1"))
 623                                         http_status(405, "Method Not Allowed");
 624                                 else
 625                                         http_status(400, "Bad Request");
 626                                 hdr_nocache();
 627                                 end_headers();
 628                                 return 0;
 629                         }
 630
 631                         cmd = c;
 632                         cmd_arg = xmalloc(n);
 633                         strncpy(cmd_arg, dir + out[0].rm_so + 1, n);
 634                         cmd_arg[n] = '\0';
 635                         dir[out[0].rm_so] = 0;
 636                         break;
 637                 }
 638                 regfree(&re);
 639         }
 640
 641         if (!cmd)
 642                 not_found("Request not supported: '%s'", dir);
 643
 644         setup_path();
 645         if (!enter_repo(dir, 0))
 646                 not_found("Not a git repository: '%s'", dir);
 647
 648         git_config(http_config, NULL);
 649         cmd->imp(cmd_arg);
 650         return 0;
 651 }