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
  11 static const char content_type[] = "Content-Type";
  12 static const char content_length[] = "Content-Length";
  13 static const char last_modified[] = "Last-Modified";
  14 static int getanyfile = 1;
  15
  16 static struct string_list *query_params;
  17
  18 struct rpc_service {
  19         const char *name;
  20         const char *config_name;
  21         signed enabled : 2;
  22 };
  23
  24 static struct rpc_service rpc_service[] = {
  25         { "upload-pack", "uploadpack", 1 },
  26         { "receive-pack", "receivepack", -1 },
  27 };
  28
  29 static struct string_list *get_parameters(void)
  30 {
  31         if (!query_params) {
  32                 const char *query = getenv("QUERY_STRING");
  33
  34                 query_params = xcalloc(1, sizeof(*query_params));
  35                 while (query && *query) {
  36                         char *name = url_decode_parameter_name(&query);
  37                         char *value = url_decode_parameter_value(&query);
  38                         struct string_list_item *i;
  39
  40                         i = string_list_lookup(query_params, name);
  41                         if (!i)
  42                                 i = string_list_insert(query_params, name);
  43                         else
  44                                 free(i->util);
  45                         i->util = value;
  46                 }
  47         }
  48         return query_params;
  49 }
  50
  51 static const char *get_parameter(const char *name)
  52 {
  53         struct string_list_item *i;
  54         i = string_list_lookup(get_parameters(), name);
  55         return i ? i->util : NULL;
  56 }
  57
  58 __attribute__((format (printf, 2, 3)))
  59 static void format_write(int fd, const char *fmt, ...)
  60 {
  61         static char buffer[1024];
  62
  63         va_list args;
  64         unsigned n;
  65
  66         va_start(args, fmt);
  67         n = vsnprintf(buffer, sizeof(buffer), fmt, args);
  68         va_end(args);
  69         if (n >= sizeof(buffer))
  70                 die("protocol error: impossibly long line");
  71
  72         safe_write(fd, buffer, n);
  73 }
  74
  75 static void http_status(unsigned code, const char *msg)
  76 {
  77         format_write(1, "Status: %u %s\r\n", code, msg);
  78 }
  79
  80 static void hdr_str(const char *name, const char *value)
  81 {
  82         format_write(1, "%s: %s\r\n", name, value);
  83 }
  84
  85 static void hdr_int(const char *name, uintmax_t value)
  86 {
  87         format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
  88 }
  89
  90 static void hdr_date(const char *name, unsigned long when)
  91 {
  92         const char *value = show_date(when, 0, DATE_RFC2822);
  93         hdr_str(name, value);
  94 }
  95
  96 static void hdr_nocache(void)
  97 {
  98         hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
  99         hdr_str("Pragma", "no-cache");
 100         hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate");
 101 }
 102
 103 static void hdr_cache_forever(void)
 104 {
 105         unsigned long now = time(NULL);
 106         hdr_date("Date", now);
 107         hdr_date("Expires", now + 31536000);
 108         hdr_str("Cache-Control", "public, max-age=31536000");
 109 }
 110
 111 static void end_headers(void)
 112 {
 113         safe_write(1, "\r\n", 2);
 114 }
 115
 116 __attribute__((format (printf, 1, 2)))
 117 static NORETURN void not_found(const char *err, ...)
 118 {
 119         va_list params;
 120
 121         http_status(404, "Not Found");
 122         hdr_nocache();
 123         end_headers();
 124
 125         va_start(params, err);
 126         if (err && *err)
 127                 vfprintf(stderr, err, params);
 128         va_end(params);
 129         exit(0);
 130 }
 131
 132 __attribute__((format (printf, 1, 2)))
 133 static NORETURN void forbidden(const char *err, ...)
 134 {
 135         va_list params;
 136
 137         http_status(403, "Forbidden");
 138         hdr_nocache();
 139         end_headers();
 140
 141         va_start(params, err);
 142         if (err && *err)
 143                 vfprintf(stderr, err, params);
 144         va_end(params);
 145         exit(0);
 146 }
 147
 148 static void select_getanyfile(void)
 149 {
 150         if (!getanyfile)
 151                 forbidden("Unsupported service: getanyfile");
 152 }
 153
 154 static void send_strbuf(const char *type, struct strbuf *buf)
 155 {
 156         hdr_int(content_length, buf->len);
 157         hdr_str(content_type, type);
 158         end_headers();
 159         safe_write(1, buf->buf, buf->len);
 160 }
 161
 162 static void send_local_file(const char *the_type, const char *name)
 163 {
 164         const char *p = git_path("%s", name);
 165         size_t buf_alloc = 8192;
 166         char *buf = xmalloc(buf_alloc);
 167         int fd;
 168         struct stat sb;
 169
 170         fd = open(p, O_RDONLY);
 171         if (fd < 0)
 172                 not_found("Cannot open '%s': %s", p, strerror(errno));
 173         if (fstat(fd, &sb) < 0)
 174                 die_errno("Cannot stat '%s'", p);
 175
 176         hdr_int(content_length, sb.st_size);
 177         hdr_str(content_type, the_type);
 178         hdr_date(last_modified, sb.st_mtime);
 179         end_headers();
 180
 181         for (;;) {
 182                 ssize_t n = xread(fd, buf, buf_alloc);
 183                 if (n < 0)
 184                         die_errno("Cannot read '%s'", p);
 185                 if (!n)
 186                         break;
 187                 safe_write(1, buf, n);
 188         }
 189         close(fd);
 190         free(buf);
 191 }
 192
 193 static void get_text_file(char *name)
 194 {
 195         select_getanyfile();
 196         hdr_nocache();
 197         send_local_file("text/plain", name);
 198 }
 199
 200 static void get_loose_object(char *name)
 201 {
 202         select_getanyfile();
 203         hdr_cache_forever();
 204         send_local_file("application/x-git-loose-object", name);
 205 }
 206
 207 static void get_pack_file(char *name)
 208 {
 209         select_getanyfile();
 210         hdr_cache_forever();
 211         send_local_file("application/x-git-packed-objects", name);
 212 }
 213
 214 static void get_idx_file(char *name)
 215 {
 216         select_getanyfile();
 217         hdr_cache_forever();
 218         send_local_file("application/x-git-packed-objects-toc", name);
 219 }
 220
 221 static int http_config(const char *var, const char *value, void *cb)
 222 {
 223         if (!strcmp(var, "http.getanyfile")) {
 224                 getanyfile = git_config_bool(var, value);
 225                 return 0;
 226         }
 227
 228         if (!prefixcmp(var, "http.")) {
 229                 int i;
 230
 231                 for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 232                         struct rpc_service *svc = &rpc_service[i];
 233                         if (!strcmp(var + 5, svc->config_name)) {
 234                                 svc->enabled = git_config_bool(var, value);
 235                                 return 0;
 236                         }
 237                 }
 238         }
 239
 240         /* we are not interested in parsing any other configuration here */
 241         return 0;
 242 }
 243
 244 static struct rpc_service *select_service(const char *name)
 245 {
 246         struct rpc_service *svc = NULL;
 247         int i;
 248
 249         if (prefixcmp(name, "git-"))
 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, name + 4)) {
 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 static void inflate_request(const char *prog_name, int out)
 273 {
 274         git_zstream stream;
 275         unsigned char in_buf[8192];
 276         unsigned char out_buf[8192];
 277         unsigned long cnt = 0;
 278
 279         memset(&stream, 0, sizeof(stream));
 280         git_inflate_init_gzip_only(&stream);
 281
 282         while (1) {
 283                 ssize_t n = xread(0, in_buf, sizeof(in_buf));
 284                 if (n <= 0)
 285                         die("request ended in the middle of the gzip stream");
 286
 287                 stream.next_in = in_buf;
 288                 stream.avail_in = n;
 289
 290                 while (0 < stream.avail_in) {
 291                         int ret;
 292
 293                         stream.next_out = out_buf;
 294                         stream.avail_out = sizeof(out_buf);
 295
 296                         ret = git_inflate(&stream, Z_NO_FLUSH);
 297                         if (ret != Z_OK && ret != Z_STREAM_END)
 298                                 die("zlib error inflating request, result %d", ret);
 299
 300                         n = stream.total_out - cnt;
 301                         if (write_in_full(out, out_buf, n) != n)
 302                                 die("%s aborted reading request", prog_name);
 303                         cnt += n;
 304
 305                         if (ret == Z_STREAM_END)
 306                                 goto done;
 307                 }
 308         }
 309
 310 done:
 311         git_inflate_end(&stream);
 312         close(out);
 313 }
 314
 315 static void run_service(const char **argv)
 316 {
 317         const char *encoding = getenv("HTTP_CONTENT_ENCODING");
 318         const char *user = getenv("REMOTE_USER");
 319         const char *host = getenv("REMOTE_ADDR");
 320         char *env[3];
 321         struct strbuf buf = STRBUF_INIT;
 322         int gzipped_request = 0;
 323         struct child_process cld;
 324
 325         if (encoding && !strcmp(encoding, "gzip"))
 326                 gzipped_request = 1;
 327         else if (encoding && !strcmp(encoding, "x-gzip"))
 328                 gzipped_request = 1;
 329
 330         if (!user || !*user)
 331                 user = "anonymous";
 332         if (!host || !*host)
 333                 host = "(none)";
 334
 335         memset(&env, 0, sizeof(env));
 336         strbuf_addf(&buf, "GIT_COMMITTER_NAME=%s", user);
 337         env[0] = strbuf_detach(&buf, NULL);
 338
 339         strbuf_addf(&buf, "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
 340         env[1] = strbuf_detach(&buf, NULL);
 341         env[2] = NULL;
 342
 343         memset(&cld, 0, sizeof(cld));
 344         cld.argv = argv;
 345         cld.env = (const char *const *)env;
 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         free(env[0]);
 361         free(env[1]);
 362         strbuf_release(&buf);
 363 }
 364
 365 static int show_text_ref(const char *name, const unsigned char *sha1,
 366         int flag, void *cb_data)
 367 {
 368         struct strbuf *buf = cb_data;
 369         struct object *o = parse_object(sha1);
 370         if (!o)
 371                 return 0;
 372
 373         strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name);
 374         if (o->type == OBJ_TAG) {
 375                 o = deref_tag(o, name, 0);
 376                 if (!o)
 377                         return 0;
 378                 strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1), name);
 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_ref(show_text_ref, &buf);
 410                 send_strbuf("text/plain", &buf);
 411         }
 412         strbuf_release(&buf);
 413 }
 414
 415 static void get_info_packs(char *arg)
 416 {
 417         size_t objdirlen = strlen(get_object_directory());
 418         struct strbuf buf = STRBUF_INIT;
 419         struct packed_git *p;
 420         size_t cnt = 0;
 421
 422         select_getanyfile();
 423         prepare_packed_git();
 424         for (p = packed_git; p; p = p->next) {
 425                 if (p->pack_local)
 426                         cnt++;
 427         }
 428
 429         strbuf_grow(&buf, cnt * 53 + 2);
 430         for (p = packed_git; p; p = p->next) {
 431                 if (p->pack_local)
 432                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
 433         }
 434         strbuf_addch(&buf, '\n');
 435
 436         hdr_nocache();
 437         send_strbuf("text/plain; charset=utf-8", &buf);
 438         strbuf_release(&buf);
 439 }
 440
 441 static void check_content_type(const char *accepted_type)
 442 {
 443         const char *actual_type = getenv("CONTENT_TYPE");
 444
 445         if (!actual_type)
 446                 actual_type = "";
 447
 448         if (strcmp(actual_type, accepted_type)) {
 449                 http_status(415, "Unsupported Media Type");
 450                 hdr_nocache();
 451                 end_headers();
 452                 format_write(1,
 453                         "Expected POST with Content-Type '%s',"
 454                         " but received '%s' instead.\n",
 455                         accepted_type, actual_type);
 456                 exit(0);
 457         }
 458 }
 459
 460 static void service_rpc(char *service_name)
 461 {
 462         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
 463         struct rpc_service *svc = select_service(service_name);
 464         struct strbuf buf = STRBUF_INIT;
 465
 466         strbuf_reset(&buf);
 467         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
 468         check_content_type(buf.buf);
 469
 470         hdr_nocache();
 471
 472         strbuf_reset(&buf);
 473         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
 474         hdr_str(content_type, buf.buf);
 475
 476         end_headers();
 477
 478         argv[0] = svc->name;
 479         run_service(argv);
 480         strbuf_release(&buf);
 481 }
 482
 483 static NORETURN void die_webcgi(const char *err, va_list params)
 484 {
 485         static int dead;
 486
 487         if (!dead) {
 488                 dead = 1;
 489                 http_status(500, "Internal Server Error");
 490                 hdr_nocache();
 491                 end_headers();
 492
 493                 vreportf("fatal: ", err, params);
 494         }
 495         exit(0); /* we successfully reported a failure ;-) */
 496 }
 497
 498 static char* getdir(void)
 499 {
 500         struct strbuf buf = STRBUF_INIT;
 501         char *pathinfo = getenv("PATH_INFO");
 502         char *root = getenv("GIT_PROJECT_ROOT");
 503         char *path = getenv("PATH_TRANSLATED");
 504
 505         if (root && *root) {
 506                 if (!pathinfo || !*pathinfo)
 507                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
 508                 if (daemon_avoid_alias(pathinfo))
 509                         die("'%s': aliased", pathinfo);
 510                 end_url_with_slash(&buf, root);
 511                 if (pathinfo[0] == '/')
 512                         pathinfo++;
 513                 strbuf_addstr(&buf, pathinfo);
 514                 return strbuf_detach(&buf, NULL);
 515         } else if (path && *path) {
 516                 return xstrdup(path);
 517         } else
 518                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
 519         return NULL;
 520 }
 521
 522 static struct service_cmd {
 523         const char *method;
 524         const char *pattern;
 525         void (*imp)(char *);
 526 } services[] = {
 527         {"GET", "/HEAD$", get_text_file},
 528         {"GET", "/info/refs$", get_info_refs},
 529         {"GET", "/objects/info/alternates$", get_text_file},
 530         {"GET", "/objects/info/http-alternates$", get_text_file},
 531         {"GET", "/objects/info/packs$", get_info_packs},
 532         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
 533         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
 534         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
 535
 536         {"POST", "/git-upload-pack$", service_rpc},
 537         {"POST", "/git-receive-pack$", service_rpc}
 538 };
 539
 540 int main(int argc, char **argv)
 541 {
 542         char *method = getenv("REQUEST_METHOD");
 543         char *dir;
 544         struct service_cmd *cmd = NULL;
 545         char *cmd_arg = NULL;
 546         int i;
 547
 548         git_extract_argv0_path(argv[0]);
 549         set_die_routine(die_webcgi);
 550
 551         if (!method)
 552                 die("No REQUEST_METHOD from server");
 553         if (!strcmp(method, "HEAD"))
 554                 method = "GET";
 555         dir = getdir();
 556
 557         for (i = 0; i < ARRAY_SIZE(services); i++) {
 558                 struct service_cmd *c = &services[i];
 559                 regex_t re;
 560                 regmatch_t out[1];
 561
 562                 if (regcomp(&re, c->pattern, REG_EXTENDED))
 563                         die("Bogus regex in service table: %s", c->pattern);
 564                 if (!regexec(&re, dir, 1, out, 0)) {
 565                         size_t n;
 566
 567                         if (strcmp(method, c->method)) {
 568                                 const char *proto = getenv("SERVER_PROTOCOL");
 569                                 if (proto && !strcmp(proto, "HTTP/1.1"))
 570                                         http_status(405, "Method Not Allowed");
 571                                 else
 572                                         http_status(400, "Bad Request");
 573                                 hdr_nocache();
 574                                 end_headers();
 575                                 return 0;
 576                         }
 577
 578                         cmd = c;
 579                         n = out[0].rm_eo - out[0].rm_so;
 580                         cmd_arg = xmalloc(n);
 581                         memcpy(cmd_arg, dir + out[0].rm_so + 1, n-1);
 582                         cmd_arg[n-1] = '\0';
 583                         dir[out[0].rm_so] = 0;
 584                         break;
 585                 }
 586                 regfree(&re);
 587         }
 588
 589         if (!cmd)
 590                 not_found("Request not supported: '%s'", dir);
 591
 592         setup_path();
 593         if (!enter_repo(dir, 0))
 594                 not_found("Not a git repository: '%s'", dir);
 595         if (!getenv("GIT_HTTP_EXPORT_ALL") &&
 596             access("git-daemon-export-ok", F_OK) )
 597                 not_found("Repository not exported: '%s'", dir);
 598
 599         git_config(http_config, NULL);
 600         cmd->imp(cmd_arg);
 601         return 0;
 602 }