Andrew's git / gitweb.git / http-backend.c
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http-backend.con commit blame: improve diagnosis for "--reverse NEW" (d993ce1)
   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_MODE(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        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
 197static void get_text_file(char *name)
 198{
 199        select_getanyfile();
 200        hdr_nocache();
 201        send_local_file("text/plain", name);
 202}
 203
 204static 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
 211static 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
 218static 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
 225static 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
 244static 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 */
 278static 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
 315static 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
 364done:
 365        git_inflate_end(&stream);
 366        close(out);
 367        free(full_request);
 368}
 369
 370static 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
 382static 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
 425static 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
 445static 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
 477static 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                const char *target_nons = strip_namespace(target);
 488
 489                strbuf_addf(buf, "ref: %s\n", target_nons);
 490        } else {
 491                strbuf_addf(buf, "%s\n", oid_to_hex(oid));
 492        }
 493
 494        return 0;
 495}
 496
 497static 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
 507static 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
 533static 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
 552static 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
 575static int dead;
 576static 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
 588static int die_webcgi_recursing(void)
 589{
 590        return dead++ > 1;
 591}
 592
 593static 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
 617static 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
 635int main(int argc, 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        git_setup_gettext();
 644
 645        git_extract_argv0_path(argv[0]);
 646        set_die_routine(die_webcgi);
 647        set_die_is_recursing_routine(die_webcgi_recursing);
 648
 649        if (!method)
 650                die("No REQUEST_METHOD from server");
 651        if (!strcmp(method, "HEAD"))
 652                method = "GET";
 653        dir = getdir();
 654
 655        for (i = 0; i < ARRAY_SIZE(services); i++) {
 656                struct service_cmd *c = &services[i];
 657                regex_t re;
 658                regmatch_t out[1];
 659
 660                if (regcomp(&re, c->pattern, REG_EXTENDED))
 661                        die("Bogus regex in service table: %s", c->pattern);
 662                if (!regexec(&re, dir, 1, out, 0)) {
 663                        size_t n;
 664
 665                        if (strcmp(method, c->method)) {
 666                                const char *proto = getenv("SERVER_PROTOCOL");
 667                                if (proto && !strcmp(proto, "HTTP/1.1")) {
 668                                        http_status(405, "Method Not Allowed");
 669                                        hdr_str("Allow", !strcmp(c->method, "GET") ?
 670                                                "GET, HEAD" : c->method);
 671                                } else
 672                                        http_status(400, "Bad Request");
 673                                hdr_nocache();
 674                                end_headers();
 675                                return 0;
 676                        }
 677
 678                        cmd = c;
 679                        n = out[0].rm_eo - out[0].rm_so;
 680                        cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
 681                        dir[out[0].rm_so] = 0;
 682                        break;
 683                }
 684                regfree(&re);
 685        }
 686
 687        if (!cmd)
 688                not_found("Request not supported: '%s'", dir);
 689
 690        setup_path();
 691        if (!enter_repo(dir, 0))
 692                not_found("Not a git repository: '%s'", dir);
 693        if (!getenv("GIT_HTTP_EXPORT_ALL") &&
 694            access("git-daemon-export-ok", F_OK) )
 695                not_found("Repository not exported: '%s'", dir);
 696
 697        http_config();
 698        max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER",
 699                                           max_request_buffer);
 700
 701        cmd->imp(cmd_arg);
 702        return 0;
 703}