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 __attribute__((format (printf, 2, 3)))
 112 static void format_write(int fd, const char *fmt, ...)
 113 {
 114         static char buffer[1024];
 115
 116         va_list args;
 117         unsigned n;
 118
 119         va_start(args, fmt);
 120         n = vsnprintf(buffer, sizeof(buffer), fmt, args);
 121         va_end(args);
 122         if (n >= sizeof(buffer))
 123                 die("protocol error: impossibly long line");
 124
 125         safe_write(fd, buffer, n);
 126 }
 127
 128 static void http_status(unsigned code, const char *msg)
 129 {
 130         format_write(1, "Status: %u %s\r\n", code, msg);
 131 }
 132
 133 static void hdr_str(const char *name, const char *value)
 134 {
 135         format_write(1, "%s: %s\r\n", name, value);
 136 }
 137
 138 static void hdr_int(const char *name, uintmax_t value)
 139 {
 140         format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
 141 }
 142
 143 static void hdr_date(const char *name, unsigned long when)
 144 {
 145         const char *value = show_date(when, 0, DATE_RFC2822);
 146         hdr_str(name, value);
 147 }
 148
 149 static void hdr_nocache(void)
 150 {
 151         hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
 152         hdr_str("Pragma", "no-cache");
 153         hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate");
 154 }
 155
 156 static void hdr_cache_forever(void)
 157 {
 158         unsigned long now = time(NULL);
 159         hdr_date("Date", now);
 160         hdr_date("Expires", now + 31536000);
 161         hdr_str("Cache-Control", "public, max-age=31536000");
 162 }
 163
 164 static void end_headers(void)
 165 {
 166         safe_write(1, "\r\n", 2);
 167 }
 168
 169 __attribute__((format (printf, 1, 2)))
 170 static NORETURN void not_found(const char *err, ...)
 171 {
 172         va_list params;
 173
 174         http_status(404, "Not Found");
 175         hdr_nocache();
 176         end_headers();
 177
 178         va_start(params, err);
 179         if (err && *err)
 180                 vfprintf(stderr, err, params);
 181         va_end(params);
 182         exit(0);
 183 }
 184
 185 __attribute__((format (printf, 1, 2)))
 186 static NORETURN void forbidden(const char *err, ...)
 187 {
 188         va_list params;
 189
 190         http_status(403, "Forbidden");
 191         hdr_nocache();
 192         end_headers();
 193
 194         va_start(params, err);
 195         if (err && *err)
 196                 vfprintf(stderr, err, params);
 197         va_end(params);
 198         exit(0);
 199 }
 200
 201 static void select_getanyfile(void)
 202 {
 203         if (!getanyfile)
 204                 forbidden("Unsupported service: getanyfile");
 205 }
 206
 207 static void send_strbuf(const char *type, struct strbuf *buf)
 208 {
 209         hdr_int(content_length, buf->len);
 210         hdr_str(content_type, type);
 211         end_headers();
 212         safe_write(1, buf->buf, buf->len);
 213 }
 214
 215 static void send_local_file(const char *the_type, const char *name)
 216 {
 217         const char *p = git_path("%s", name);
 218         size_t buf_alloc = 8192;
 219         char *buf = xmalloc(buf_alloc);
 220         int fd;
 221         struct stat sb;
 222
 223         fd = open(p, O_RDONLY);
 224         if (fd < 0)
 225                 not_found("Cannot open '%s': %s", p, strerror(errno));
 226         if (fstat(fd, &sb) < 0)
 227                 die_errno("Cannot stat '%s'", p);
 228
 229         hdr_int(content_length, sb.st_size);
 230         hdr_str(content_type, the_type);
 231         hdr_date(last_modified, sb.st_mtime);
 232         end_headers();
 233
 234         for (;;) {
 235                 ssize_t n = xread(fd, buf, buf_alloc);
 236                 if (n < 0)
 237                         die_errno("Cannot read '%s'", p);
 238                 if (!n)
 239                         break;
 240                 safe_write(1, buf, n);
 241         }
 242         close(fd);
 243         free(buf);
 244 }
 245
 246 static void get_text_file(char *name)
 247 {
 248         select_getanyfile();
 249         hdr_nocache();
 250         send_local_file("text/plain", name);
 251 }
 252
 253 static void get_loose_object(char *name)
 254 {
 255         select_getanyfile();
 256         hdr_cache_forever();
 257         send_local_file("application/x-git-loose-object", name);
 258 }
 259
 260 static void get_pack_file(char *name)
 261 {
 262         select_getanyfile();
 263         hdr_cache_forever();
 264         send_local_file("application/x-git-packed-objects", name);
 265 }
 266
 267 static void get_idx_file(char *name)
 268 {
 269         select_getanyfile();
 270         hdr_cache_forever();
 271         send_local_file("application/x-git-packed-objects-toc", name);
 272 }
 273
 274 static int http_config(const char *var, const char *value, void *cb)
 275 {
 276         if (!strcmp(var, "http.getanyfile")) {
 277                 getanyfile = git_config_bool(var, value);
 278                 return 0;
 279         }
 280
 281         if (!prefixcmp(var, "http.")) {
 282                 int i;
 283
 284                 for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 285                         struct rpc_service *svc = &rpc_service[i];
 286                         if (!strcmp(var + 5, svc->config_name)) {
 287                                 svc->enabled = git_config_bool(var, value);
 288                                 return 0;
 289                         }
 290                 }
 291         }
 292
 293         /* we are not interested in parsing any other configuration here */
 294         return 0;
 295 }
 296
 297 static struct rpc_service *select_service(const char *name)
 298 {
 299         struct rpc_service *svc = NULL;
 300         int i;
 301
 302         if (prefixcmp(name, "git-"))
 303                 forbidden("Unsupported service: '%s'", name);
 304
 305         for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 306                 struct rpc_service *s = &rpc_service[i];
 307                 if (!strcmp(s->name, name + 4)) {
 308                         svc = s;
 309                         break;
 310                 }
 311         }
 312
 313         if (!svc)
 314                 forbidden("Unsupported service: '%s'", name);
 315
 316         if (svc->enabled < 0) {
 317                 const char *user = getenv("REMOTE_USER");
 318                 svc->enabled = (user && *user) ? 1 : 0;
 319         }
 320         if (!svc->enabled)
 321                 forbidden("Service not enabled: '%s'", svc->name);
 322         return svc;
 323 }
 324
 325 static void inflate_request(const char *prog_name, int out)
 326 {
 327         z_stream stream;
 328         unsigned char in_buf[8192];
 329         unsigned char out_buf[8192];
 330         unsigned long cnt = 0;
 331         int ret;
 332
 333         memset(&stream, 0, sizeof(stream));
 334         ret = inflateInit2(&stream, (15 + 16));
 335         if (ret != Z_OK)
 336                 die("cannot start zlib inflater, zlib err %d", ret);
 337
 338         while (1) {
 339                 ssize_t n = xread(0, in_buf, sizeof(in_buf));
 340                 if (n <= 0)
 341                         die("request ended in the middle of the gzip stream");
 342
 343                 stream.next_in = in_buf;
 344                 stream.avail_in = n;
 345
 346                 while (0 < stream.avail_in) {
 347                         int ret;
 348
 349                         stream.next_out = out_buf;
 350                         stream.avail_out = sizeof(out_buf);
 351
 352                         ret = inflate(&stream, Z_NO_FLUSH);
 353                         if (ret != Z_OK && ret != Z_STREAM_END)
 354                                 die("zlib error inflating request, result %d", ret);
 355
 356                         n = stream.total_out - cnt;
 357                         if (write_in_full(out, out_buf, n) != n)
 358                                 die("%s aborted reading request", prog_name);
 359                         cnt += n;
 360
 361                         if (ret == Z_STREAM_END)
 362                                 goto done;
 363                 }
 364         }
 365
 366 done:
 367         inflateEnd(&stream);
 368         close(out);
 369 }
 370
 371 static void run_service(const char **argv)
 372 {
 373         const char *encoding = getenv("HTTP_CONTENT_ENCODING");
 374         const char *user = getenv("REMOTE_USER");
 375         const char *host = getenv("REMOTE_ADDR");
 376         char *env[3];
 377         struct strbuf buf = STRBUF_INIT;
 378         int gzipped_request = 0;
 379         struct child_process cld;
 380
 381         if (encoding && !strcmp(encoding, "gzip"))
 382                 gzipped_request = 1;
 383         else if (encoding && !strcmp(encoding, "x-gzip"))
 384                 gzipped_request = 1;
 385
 386         if (!user || !*user)
 387                 user = "anonymous";
 388         if (!host || !*host)
 389                 host = "(none)";
 390
 391         memset(&env, 0, sizeof(env));
 392         strbuf_addf(&buf, "GIT_COMMITTER_NAME=%s", user);
 393         env[0] = strbuf_detach(&buf, NULL);
 394
 395         strbuf_addf(&buf, "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
 396         env[1] = strbuf_detach(&buf, NULL);
 397         env[2] = NULL;
 398
 399         memset(&cld, 0, sizeof(cld));
 400         cld.argv = argv;
 401         cld.env = (const char *const *)env;
 402         if (gzipped_request)
 403                 cld.in = -1;
 404         cld.git_cmd = 1;
 405         if (start_command(&cld))
 406                 exit(1);
 407
 408         close(1);
 409         if (gzipped_request)
 410                 inflate_request(argv[0], cld.in);
 411         else
 412                 close(0);
 413
 414         if (finish_command(&cld))
 415                 exit(1);
 416         free(env[0]);
 417         free(env[1]);
 418         strbuf_release(&buf);
 419 }
 420
 421 static int show_text_ref(const char *name, const unsigned char *sha1,
 422         int flag, void *cb_data)
 423 {
 424         struct strbuf *buf = cb_data;
 425         struct object *o = parse_object(sha1);
 426         if (!o)
 427                 return 0;
 428
 429         strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name);
 430         if (o->type == OBJ_TAG) {
 431                 o = deref_tag(o, name, 0);
 432                 if (!o)
 433                         return 0;
 434                 strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1), name);
 435         }
 436         return 0;
 437 }
 438
 439 static void get_info_refs(char *arg)
 440 {
 441         const char *service_name = get_parameter("service");
 442         struct strbuf buf = STRBUF_INIT;
 443
 444         hdr_nocache();
 445
 446         if (service_name) {
 447                 const char *argv[] = {NULL /* service name */,
 448                         "--stateless-rpc", "--advertise-refs",
 449                         ".", NULL};
 450                 struct rpc_service *svc = select_service(service_name);
 451
 452                 strbuf_addf(&buf, "application/x-git-%s-advertisement",
 453                         svc->name);
 454                 hdr_str(content_type, buf.buf);
 455                 end_headers();
 456
 457                 packet_write(1, "# service=git-%s\n", svc->name);
 458                 packet_flush(1);
 459
 460                 argv[0] = svc->name;
 461                 run_service(argv);
 462
 463         } else {
 464                 select_getanyfile();
 465                 for_each_ref(show_text_ref, &buf);
 466                 send_strbuf("text/plain", &buf);
 467         }
 468         strbuf_release(&buf);
 469 }
 470
 471 static void get_info_packs(char *arg)
 472 {
 473         size_t objdirlen = strlen(get_object_directory());
 474         struct strbuf buf = STRBUF_INIT;
 475         struct packed_git *p;
 476         size_t cnt = 0;
 477
 478         select_getanyfile();
 479         prepare_packed_git();
 480         for (p = packed_git; p; p = p->next) {
 481                 if (p->pack_local)
 482                         cnt++;
 483         }
 484
 485         strbuf_grow(&buf, cnt * 53 + 2);
 486         for (p = packed_git; p; p = p->next) {
 487                 if (p->pack_local)
 488                         strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
 489         }
 490         strbuf_addch(&buf, '\n');
 491
 492         hdr_nocache();
 493         send_strbuf("text/plain; charset=utf-8", &buf);
 494         strbuf_release(&buf);
 495 }
 496
 497 static void check_content_type(const char *accepted_type)
 498 {
 499         const char *actual_type = getenv("CONTENT_TYPE");
 500
 501         if (!actual_type)
 502                 actual_type = "";
 503
 504         if (strcmp(actual_type, accepted_type)) {
 505                 http_status(415, "Unsupported Media Type");
 506                 hdr_nocache();
 507                 end_headers();
 508                 format_write(1,
 509                         "Expected POST with Content-Type '%s',"
 510                         " but received '%s' instead.\n",
 511                         accepted_type, actual_type);
 512                 exit(0);
 513         }
 514 }
 515
 516 static void service_rpc(char *service_name)
 517 {
 518         const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
 519         struct rpc_service *svc = select_service(service_name);
 520         struct strbuf buf = STRBUF_INIT;
 521
 522         strbuf_reset(&buf);
 523         strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
 524         check_content_type(buf.buf);
 525
 526         hdr_nocache();
 527
 528         strbuf_reset(&buf);
 529         strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
 530         hdr_str(content_type, buf.buf);
 531
 532         end_headers();
 533
 534         argv[0] = svc->name;
 535         run_service(argv);
 536         strbuf_release(&buf);
 537 }
 538
 539 static NORETURN void die_webcgi(const char *err, va_list params)
 540 {
 541         char buffer[1000];
 542
 543         http_status(500, "Internal Server Error");
 544         hdr_nocache();
 545         end_headers();
 546
 547         vsnprintf(buffer, sizeof(buffer), err, params);
 548         fprintf(stderr, "fatal: %s\n", buffer);
 549         exit(0);
 550 }
 551
 552 static char* getdir(void)
 553 {
 554         struct strbuf buf = STRBUF_INIT;
 555         char *pathinfo = getenv("PATH_INFO");
 556         char *root = getenv("GIT_PROJECT_ROOT");
 557         char *path = getenv("PATH_TRANSLATED");
 558
 559         if (root && *root) {
 560                 if (!pathinfo || !*pathinfo)
 561                         die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
 562                 if (daemon_avoid_alias(pathinfo))
 563                         die("'%s': aliased", pathinfo);
 564                 strbuf_addstr(&buf, root);
 565                 if (buf.buf[buf.len - 1] != '/')
 566                         strbuf_addch(&buf, '/');
 567                 if (pathinfo[0] == '/')
 568                         pathinfo++;
 569                 strbuf_addstr(&buf, pathinfo);
 570                 return strbuf_detach(&buf, NULL);
 571         } else if (path && *path) {
 572                 return xstrdup(path);
 573         } else
 574                 die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
 575         return NULL;
 576 }
 577
 578 static struct service_cmd {
 579         const char *method;
 580         const char *pattern;
 581         void (*imp)(char *);
 582 } services[] = {
 583         {"GET", "/HEAD$", get_text_file},
 584         {"GET", "/info/refs$", get_info_refs},
 585         {"GET", "/objects/info/alternates$", get_text_file},
 586         {"GET", "/objects/info/http-alternates$", get_text_file},
 587         {"GET", "/objects/info/packs$", get_info_packs},
 588         {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
 589         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
 590         {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
 591
 592         {"POST", "/git-upload-pack$", service_rpc},
 593         {"POST", "/git-receive-pack$", service_rpc}
 594 };
 595
 596 int main(int argc, char **argv)
 597 {
 598         char *method = getenv("REQUEST_METHOD");
 599         char *dir;
 600         struct service_cmd *cmd = NULL;
 601         char *cmd_arg = NULL;
 602         int i;
 603
 604         git_extract_argv0_path(argv[0]);
 605         set_die_routine(die_webcgi);
 606
 607         if (!method)
 608                 die("No REQUEST_METHOD from server");
 609         if (!strcmp(method, "HEAD"))
 610                 method = "GET";
 611         dir = getdir();
 612
 613         for (i = 0; i < ARRAY_SIZE(services); i++) {
 614                 struct service_cmd *c = &services[i];
 615                 regex_t re;
 616                 regmatch_t out[1];
 617
 618                 if (regcomp(&re, c->pattern, REG_EXTENDED))
 619                         die("Bogus regex in service table: %s", c->pattern);
 620                 if (!regexec(&re, dir, 1, out, 0)) {
 621                         size_t n;
 622
 623                         if (strcmp(method, c->method)) {
 624                                 const char *proto = getenv("SERVER_PROTOCOL");
 625                                 if (proto && !strcmp(proto, "HTTP/1.1"))
 626                                         http_status(405, "Method Not Allowed");
 627                                 else
 628                                         http_status(400, "Bad Request");
 629                                 hdr_nocache();
 630                                 end_headers();
 631                                 return 0;
 632                         }
 633
 634                         cmd = c;
 635                         n = out[0].rm_eo - out[0].rm_so;
 636                         cmd_arg = xmalloc(n);
 637                         memcpy(cmd_arg, dir + out[0].rm_so + 1, n-1);
 638                         cmd_arg[n-1] = '\0';
 639                         dir[out[0].rm_so] = 0;
 640                         break;
 641                 }
 642                 regfree(&re);
 643         }
 644
 645         if (!cmd)
 646                 not_found("Request not supported: '%s'", dir);
 647
 648         setup_path();
 649         if (!enter_repo(dir, 0))
 650                 not_found("Not a git repository: '%s'", dir);
 651
 652         git_config(http_config, NULL);
 653         cmd->imp(cmd_arg);
 654         return 0;
 655 }