Andrew's git / gitweb.git / http-backend.c
?
http-backend.con commit push: support signing pushes iff the server supports it (3026109)
   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
  12static const char content_type[] = "Content-Type";
  13static const char content_length[] = "Content-Length";
  14static const char last_modified[] = "Last-Modified";
  15static int getanyfile = 1;
  16static unsigned long max_request_buffer = 10 * 1024 * 1024;
  17
  18static struct string_list *query_params;
  19
  20struct rpc_service {
  21        const char *name;
  22        const char *config_name;
  23        unsigned buffer_input : 1;
  24        signed enabled : 2;
  25};
  26
  27static struct rpc_service rpc_service[] = {
  28        { "upload-pack", "uploadpack", 1, 1 },
  29        { "receive-pack", "receivepack", 0, -1 },
  30};
  31
  32static 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
  54static 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)))
  62static 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
  78static void http_status(unsigned code, const char *msg)
  79{
  80        format_write(1, "Status: %u %s\r\n", code, msg);
  81}
  82
  83static void hdr_str(const char *name, const char *value)
  84{
  85        format_write(1, "%s: %s\r\n", name, value);
  86}
  87
  88static void hdr_int(const char *name, uintmax_t value)
  89{
  90        format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
  91}
  92
  93static 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
  99static 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
 106static 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
 114static void end_headers(void)
 115{
 116        write_or_die(1, "\r\n", 2);
 117}
 118
 119__attribute__((format (printf, 1, 2)))
 120static 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)))
 136static 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
 151static void select_getanyfile(void)
 152{
 153        if (!getanyfile)
 154                forbidden("Unsupported service: getanyfile");
 155}
 156
 157static 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
 165static 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
 196static void get_text_file(char *name)
 197{
 198        select_getanyfile();
 199        hdr_nocache();
 200        send_local_file("text/plain", name);
 201}
 202
 203static 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
 210static 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
 217static 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
 224static 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
 243static 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 */
 277static 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
 314static 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
 363done:
 364        git_inflate_end(&stream);
 365        close(out);
 366        free(full_request);
 367}
 368
 369static 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
 381static 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
 424static 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
 444static 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
 476static 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
 496static 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
 506static 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
 532static 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
 551static 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
 574static int dead;
 575static 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
 587static int die_webcgi_recursing(void)
 588{
 589        return dead++ > 1;
 590}
 591
 592static 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
 616static 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
 634int 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}