Andrew's git / gitweb.git / http-backend.c
?
http-backend.con commit Merge branch 'jk/pager-in-use' (6a5ff7a)
   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(struct strbuf *hdr, unsigned code, const char *msg)
  79{
  80        strbuf_addf(hdr, "Status: %u %s\r\n", code, msg);
  81}
  82
  83static void hdr_str(struct strbuf *hdr, const char *name, const char *value)
  84{
  85        strbuf_addf(hdr, "%s: %s\r\n", name, value);
  86}
  87
  88static void hdr_int(struct strbuf *hdr, const char *name, uintmax_t value)
  89{
  90        strbuf_addf(hdr, "%s: %" PRIuMAX "\r\n", name, value);
  91}
  92
  93static void hdr_date(struct strbuf *hdr, const char *name, unsigned long when)
  94{
  95        const char *value = show_date(when, 0, DATE_MODE(RFC2822));
  96        hdr_str(hdr, name, value);
  97}
  98
  99static void hdr_nocache(struct strbuf *hdr)
 100{
 101        hdr_str(hdr, "Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
 102        hdr_str(hdr, "Pragma", "no-cache");
 103        hdr_str(hdr, "Cache-Control", "no-cache, max-age=0, must-revalidate");
 104}
 105
 106static void hdr_cache_forever(struct strbuf *hdr)
 107{
 108        unsigned long now = time(NULL);
 109        hdr_date(hdr, "Date", now);
 110        hdr_date(hdr, "Expires", now + 31536000);
 111        hdr_str(hdr, "Cache-Control", "public, max-age=31536000");
 112}
 113
 114static void end_headers(struct strbuf *hdr)
 115{
 116        strbuf_add(hdr, "\r\n", 2);
 117        write_or_die(1, hdr->buf, hdr->len);
 118        strbuf_release(hdr);
 119}
 120
 121__attribute__((format (printf, 2, 3)))
 122static NORETURN void not_found(struct strbuf *hdr, const char *err, ...)
 123{
 124        va_list params;
 125
 126        http_status(hdr, 404, "Not Found");
 127        hdr_nocache(hdr);
 128        end_headers(hdr);
 129
 130        va_start(params, err);
 131        if (err && *err)
 132                vfprintf(stderr, err, params);
 133        va_end(params);
 134        exit(0);
 135}
 136
 137__attribute__((format (printf, 2, 3)))
 138static NORETURN void forbidden(struct strbuf *hdr, const char *err, ...)
 139{
 140        va_list params;
 141
 142        http_status(hdr, 403, "Forbidden");
 143        hdr_nocache(hdr);
 144        end_headers(hdr);
 145
 146        va_start(params, err);
 147        if (err && *err)
 148                vfprintf(stderr, err, params);
 149        va_end(params);
 150        exit(0);
 151}
 152
 153static void select_getanyfile(struct strbuf *hdr)
 154{
 155        if (!getanyfile)
 156                forbidden(hdr, "Unsupported service: getanyfile");
 157}
 158
 159static void send_strbuf(struct strbuf *hdr,
 160                        const char *type, struct strbuf *buf)
 161{
 162        hdr_int(hdr, content_length, buf->len);
 163        hdr_str(hdr, content_type, type);
 164        end_headers(hdr);
 165        write_or_die(1, buf->buf, buf->len);
 166}
 167
 168static void send_local_file(struct strbuf *hdr, const char *the_type,
 169                                const char *name)
 170{
 171        char *p = git_pathdup("%s", name);
 172        size_t buf_alloc = 8192;
 173        char *buf = xmalloc(buf_alloc);
 174        int fd;
 175        struct stat sb;
 176
 177        fd = open(p, O_RDONLY);
 178        if (fd < 0)
 179                not_found(hdr, "Cannot open '%s': %s", p, strerror(errno));
 180        if (fstat(fd, &sb) < 0)
 181                die_errno("Cannot stat '%s'", p);
 182
 183        hdr_int(hdr, content_length, sb.st_size);
 184        hdr_str(hdr, content_type, the_type);
 185        hdr_date(hdr, last_modified, sb.st_mtime);
 186        end_headers(hdr);
 187
 188        for (;;) {
 189                ssize_t n = xread(fd, buf, buf_alloc);
 190                if (n < 0)
 191                        die_errno("Cannot read '%s'", p);
 192                if (!n)
 193                        break;
 194                write_or_die(1, buf, n);
 195        }
 196        close(fd);
 197        free(buf);
 198        free(p);
 199}
 200
 201static void get_text_file(struct strbuf *hdr, char *name)
 202{
 203        select_getanyfile(hdr);
 204        hdr_nocache(hdr);
 205        send_local_file(hdr, "text/plain", name);
 206}
 207
 208static void get_loose_object(struct strbuf *hdr, char *name)
 209{
 210        select_getanyfile(hdr);
 211        hdr_cache_forever(hdr);
 212        send_local_file(hdr, "application/x-git-loose-object", name);
 213}
 214
 215static void get_pack_file(struct strbuf *hdr, char *name)
 216{
 217        select_getanyfile(hdr);
 218        hdr_cache_forever(hdr);
 219        send_local_file(hdr, "application/x-git-packed-objects", name);
 220}
 221
 222static void get_idx_file(struct strbuf *hdr, char *name)
 223{
 224        select_getanyfile(hdr);
 225        hdr_cache_forever(hdr);
 226        send_local_file(hdr, "application/x-git-packed-objects-toc", name);
 227}
 228
 229static void http_config(void)
 230{
 231        int i, value = 0;
 232        struct strbuf var = STRBUF_INIT;
 233
 234        git_config_get_bool("http.getanyfile", &getanyfile);
 235        git_config_get_ulong("http.maxrequestbuffer", &max_request_buffer);
 236
 237        for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 238                struct rpc_service *svc = &rpc_service[i];
 239                strbuf_addf(&var, "http.%s", svc->config_name);
 240                if (!git_config_get_bool(var.buf, &value))
 241                        svc->enabled = value;
 242                strbuf_reset(&var);
 243        }
 244
 245        strbuf_release(&var);
 246}
 247
 248static struct rpc_service *select_service(struct strbuf *hdr, const char *name)
 249{
 250        const char *svc_name;
 251        struct rpc_service *svc = NULL;
 252        int i;
 253
 254        if (!skip_prefix(name, "git-", &svc_name))
 255                forbidden(hdr, "Unsupported service: '%s'", name);
 256
 257        for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
 258                struct rpc_service *s = &rpc_service[i];
 259                if (!strcmp(s->name, svc_name)) {
 260                        svc = s;
 261                        break;
 262                }
 263        }
 264
 265        if (!svc)
 266                forbidden(hdr, "Unsupported service: '%s'", name);
 267
 268        if (svc->enabled < 0) {
 269                const char *user = getenv("REMOTE_USER");
 270                svc->enabled = (user && *user) ? 1 : 0;
 271        }
 272        if (!svc->enabled)
 273                forbidden(hdr, "Service not enabled: '%s'", svc->name);
 274        return svc;
 275}
 276
 277/*
 278 * This is basically strbuf_read(), except that if we
 279 * hit max_request_buffer we die (we'd rather reject a
 280 * maliciously large request than chew up infinite memory).
 281 */
 282static ssize_t read_request(int fd, unsigned char **out)
 283{
 284        size_t len = 0, alloc = 8192;
 285        unsigned char *buf = xmalloc(alloc);
 286
 287        if (max_request_buffer < alloc)
 288                max_request_buffer = alloc;
 289
 290        while (1) {
 291                ssize_t cnt;
 292
 293                cnt = read_in_full(fd, buf + len, alloc - len);
 294                if (cnt < 0) {
 295                        free(buf);
 296                        return -1;
 297                }
 298
 299                /* partial read from read_in_full means we hit EOF */
 300                len += cnt;
 301                if (len < alloc) {
 302                        *out = buf;
 303                        return len;
 304                }
 305
 306                /* otherwise, grow and try again (if we can) */
 307                if (alloc == max_request_buffer)
 308                        die("request was larger than our maximum size (%lu);"
 309                            " try setting GIT_HTTP_MAX_REQUEST_BUFFER",
 310                            max_request_buffer);
 311
 312                alloc = alloc_nr(alloc);
 313                if (alloc > max_request_buffer)
 314                        alloc = max_request_buffer;
 315                REALLOC_ARRAY(buf, alloc);
 316        }
 317}
 318
 319static void inflate_request(const char *prog_name, int out, int buffer_input)
 320{
 321        git_zstream stream;
 322        unsigned char *full_request = NULL;
 323        unsigned char in_buf[8192];
 324        unsigned char out_buf[8192];
 325        unsigned long cnt = 0;
 326
 327        memset(&stream, 0, sizeof(stream));
 328        git_inflate_init_gzip_only(&stream);
 329
 330        while (1) {
 331                ssize_t n;
 332
 333                if (buffer_input) {
 334                        if (full_request)
 335                                n = 0; /* nothing left to read */
 336                        else
 337                                n = read_request(0, &full_request);
 338                        stream.next_in = full_request;
 339                } else {
 340                        n = xread(0, in_buf, sizeof(in_buf));
 341                        stream.next_in = in_buf;
 342                }
 343
 344                if (n <= 0)
 345                        die("request ended in the middle of the gzip stream");
 346                stream.avail_in = n;
 347
 348                while (0 < stream.avail_in) {
 349                        int ret;
 350
 351                        stream.next_out = out_buf;
 352                        stream.avail_out = sizeof(out_buf);
 353
 354                        ret = git_inflate(&stream, Z_NO_FLUSH);
 355                        if (ret != Z_OK && ret != Z_STREAM_END)
 356                                die("zlib error inflating request, result %d", ret);
 357
 358                        n = stream.total_out - cnt;
 359                        if (write_in_full(out, out_buf, n) != n)
 360                                die("%s aborted reading request", prog_name);
 361                        cnt += n;
 362
 363                        if (ret == Z_STREAM_END)
 364                                goto done;
 365                }
 366        }
 367
 368done:
 369        git_inflate_end(&stream);
 370        close(out);
 371        free(full_request);
 372}
 373
 374static void copy_request(const char *prog_name, int out)
 375{
 376        unsigned char *buf;
 377        ssize_t n = read_request(0, &buf);
 378        if (n < 0)
 379                die_errno("error reading request body");
 380        if (write_in_full(out, buf, n) != n)
 381                die("%s aborted reading request", prog_name);
 382        close(out);
 383        free(buf);
 384}
 385
 386static void run_service(const char **argv, int buffer_input)
 387{
 388        const char *encoding = getenv("HTTP_CONTENT_ENCODING");
 389        const char *user = getenv("REMOTE_USER");
 390        const char *host = getenv("REMOTE_ADDR");
 391        int gzipped_request = 0;
 392        struct child_process cld = CHILD_PROCESS_INIT;
 393
 394        if (encoding && !strcmp(encoding, "gzip"))
 395                gzipped_request = 1;
 396        else if (encoding && !strcmp(encoding, "x-gzip"))
 397                gzipped_request = 1;
 398
 399        if (!user || !*user)
 400                user = "anonymous";
 401        if (!host || !*host)
 402                host = "(none)";
 403
 404        if (!getenv("GIT_COMMITTER_NAME"))
 405                argv_array_pushf(&cld.env_array, "GIT_COMMITTER_NAME=%s", user);
 406        if (!getenv("GIT_COMMITTER_EMAIL"))
 407                argv_array_pushf(&cld.env_array,
 408                                 "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
 409
 410        cld.argv = argv;
 411        if (buffer_input || gzipped_request)
 412                cld.in = -1;
 413        cld.git_cmd = 1;
 414        if (start_command(&cld))
 415                exit(1);
 416
 417        close(1);
 418        if (gzipped_request)
 419                inflate_request(argv[0], cld.in, buffer_input);
 420        else if (buffer_input)
 421                copy_request(argv[0], cld.in);
 422        else
 423                close(0);
 424
 425        if (finish_command(&cld))
 426                exit(1);
 427}
 428
 429static int show_text_ref(const char *name, const struct object_id *oid,
 430                         int flag, void *cb_data)
 431{
 432        const char *name_nons = strip_namespace(name);
 433        struct strbuf *buf = cb_data;
 434        struct object *o = parse_object(oid->hash);
 435        if (!o)
 436                return 0;
 437
 438        strbuf_addf(buf, "%s\t%s\n", oid_to_hex(oid), name_nons);
 439        if (o->type == OBJ_TAG) {
 440                o = deref_tag(o, name, 0);
 441                if (!o)
 442                        return 0;
 443                strbuf_addf(buf, "%s\t%s^{}\n", oid_to_hex(&o->oid),
 444                            name_nons);
 445        }
 446        return 0;
 447}
 448
 449static void get_info_refs(struct strbuf *hdr, char *arg)
 450{
 451        const char *service_name = get_parameter("service");
 452        struct strbuf buf = STRBUF_INIT;
 453
 454        hdr_nocache(hdr);
 455
 456        if (service_name) {
 457                const char *argv[] = {NULL /* service name */,
 458                        "--stateless-rpc", "--advertise-refs",
 459                        ".", NULL};
 460                struct rpc_service *svc = select_service(hdr, service_name);
 461
 462                strbuf_addf(&buf, "application/x-git-%s-advertisement",
 463                        svc->name);
 464                hdr_str(hdr, content_type, buf.buf);
 465                end_headers(hdr);
 466
 467                packet_write_fmt(1, "# service=git-%s\n", svc->name);
 468                packet_flush(1);
 469
 470                argv[0] = svc->name;
 471                run_service(argv, 0);
 472
 473        } else {
 474                select_getanyfile(hdr);
 475                for_each_namespaced_ref(show_text_ref, &buf);
 476                send_strbuf(hdr, "text/plain", &buf);
 477        }
 478        strbuf_release(&buf);
 479}
 480
 481static int show_head_ref(const char *refname, const struct object_id *oid,
 482                         int flag, void *cb_data)
 483{
 484        struct strbuf *buf = cb_data;
 485
 486        if (flag & REF_ISSYMREF) {
 487                struct object_id unused;
 488                const char *target = resolve_ref_unsafe(refname,
 489                                                        RESOLVE_REF_READING,
 490                                                        unused.hash, NULL);
 491
 492                if (target)
 493                        strbuf_addf(buf, "ref: %s\n", strip_namespace(target));
 494        } else {
 495                strbuf_addf(buf, "%s\n", oid_to_hex(oid));
 496        }
 497
 498        return 0;
 499}
 500
 501static void get_head(struct strbuf *hdr, char *arg)
 502{
 503        struct strbuf buf = STRBUF_INIT;
 504
 505        select_getanyfile(hdr);
 506        head_ref_namespaced(show_head_ref, &buf);
 507        send_strbuf(hdr, "text/plain", &buf);
 508        strbuf_release(&buf);
 509}
 510
 511static void get_info_packs(struct strbuf *hdr, char *arg)
 512{
 513        size_t objdirlen = strlen(get_object_directory());
 514        struct strbuf buf = STRBUF_INIT;
 515        struct packed_git *p;
 516        size_t cnt = 0;
 517
 518        select_getanyfile(hdr);
 519        prepare_packed_git();
 520        for (p = packed_git; p; p = p->next) {
 521                if (p->pack_local)
 522                        cnt++;
 523        }
 524
 525        strbuf_grow(&buf, cnt * 53 + 2);
 526        for (p = packed_git; p; p = p->next) {
 527                if (p->pack_local)
 528                        strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
 529        }
 530        strbuf_addch(&buf, '\n');
 531
 532        hdr_nocache(hdr);
 533        send_strbuf(hdr, "text/plain; charset=utf-8", &buf);
 534        strbuf_release(&buf);
 535}
 536
 537static void check_content_type(struct strbuf *hdr, const char *accepted_type)
 538{
 539        const char *actual_type = getenv("CONTENT_TYPE");
 540
 541        if (!actual_type)
 542                actual_type = "";
 543
 544        if (strcmp(actual_type, accepted_type)) {
 545                http_status(hdr, 415, "Unsupported Media Type");
 546                hdr_nocache(hdr);
 547                end_headers(hdr);
 548                format_write(1,
 549                        "Expected POST with Content-Type '%s',"
 550                        " but received '%s' instead.\n",
 551                        accepted_type, actual_type);
 552                exit(0);
 553        }
 554}
 555
 556static void service_rpc(struct strbuf *hdr, char *service_name)
 557{
 558        const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
 559        struct rpc_service *svc = select_service(hdr, service_name);
 560        struct strbuf buf = STRBUF_INIT;
 561
 562        strbuf_reset(&buf);
 563        strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
 564        check_content_type(hdr, buf.buf);
 565
 566        hdr_nocache(hdr);
 567
 568        strbuf_reset(&buf);
 569        strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
 570        hdr_str(hdr, content_type, buf.buf);
 571
 572        end_headers(hdr);
 573
 574        argv[0] = svc->name;
 575        run_service(argv, svc->buffer_input);
 576        strbuf_release(&buf);
 577}
 578
 579static int dead;
 580static NORETURN void die_webcgi(const char *err, va_list params)
 581{
 582        if (dead <= 1) {
 583                struct strbuf hdr = STRBUF_INIT;
 584
 585                vreportf("fatal: ", err, params);
 586
 587                http_status(&hdr, 500, "Internal Server Error");
 588                hdr_nocache(&hdr);
 589                end_headers(&hdr);
 590        }
 591        exit(0); /* we successfully reported a failure ;-) */
 592}
 593
 594static int die_webcgi_recursing(void)
 595{
 596        return dead++ > 1;
 597}
 598
 599static char* getdir(void)
 600{
 601        struct strbuf buf = STRBUF_INIT;
 602        char *pathinfo = getenv("PATH_INFO");
 603        char *root = getenv("GIT_PROJECT_ROOT");
 604        char *path = getenv("PATH_TRANSLATED");
 605
 606        if (root && *root) {
 607                if (!pathinfo || !*pathinfo)
 608                        die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
 609                if (daemon_avoid_alias(pathinfo))
 610                        die("'%s': aliased", pathinfo);
 611                end_url_with_slash(&buf, root);
 612                if (pathinfo[0] == '/')
 613                        pathinfo++;
 614                strbuf_addstr(&buf, pathinfo);
 615                return strbuf_detach(&buf, NULL);
 616        } else if (path && *path) {
 617                return xstrdup(path);
 618        } else
 619                die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
 620        return NULL;
 621}
 622
 623static struct service_cmd {
 624        const char *method;
 625        const char *pattern;
 626        void (*imp)(struct strbuf *, char *);
 627} services[] = {
 628        {"GET", "/HEAD$", get_head},
 629        {"GET", "/info/refs$", get_info_refs},
 630        {"GET", "/objects/info/alternates$", get_text_file},
 631        {"GET", "/objects/info/http-alternates$", get_text_file},
 632        {"GET", "/objects/info/packs$", get_info_packs},
 633        {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
 634        {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
 635        {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
 636
 637        {"POST", "/git-upload-pack$", service_rpc},
 638        {"POST", "/git-receive-pack$", service_rpc}
 639};
 640
 641static int bad_request(struct strbuf *hdr, const struct service_cmd *c)
 642{
 643        const char *proto = getenv("SERVER_PROTOCOL");
 644
 645        if (proto && !strcmp(proto, "HTTP/1.1")) {
 646                http_status(hdr, 405, "Method Not Allowed");
 647                hdr_str(hdr, "Allow",
 648                        !strcmp(c->method, "GET") ? "GET, HEAD" : c->method);
 649        } else
 650                http_status(hdr, 400, "Bad Request");
 651        hdr_nocache(hdr);
 652        end_headers(hdr);
 653        return 0;
 654}
 655
 656int cmd_main(int argc, const char **argv)
 657{
 658        char *method = getenv("REQUEST_METHOD");
 659        char *dir;
 660        struct service_cmd *cmd = NULL;
 661        char *cmd_arg = NULL;
 662        int i;
 663        struct strbuf hdr = STRBUF_INIT;
 664
 665        set_die_routine(die_webcgi);
 666        set_die_is_recursing_routine(die_webcgi_recursing);
 667
 668        if (!method)
 669                die("No REQUEST_METHOD from server");
 670        if (!strcmp(method, "HEAD"))
 671                method = "GET";
 672        dir = getdir();
 673
 674        for (i = 0; i < ARRAY_SIZE(services); i++) {
 675                struct service_cmd *c = &services[i];
 676                regex_t re;
 677                regmatch_t out[1];
 678
 679                if (regcomp(&re, c->pattern, REG_EXTENDED))
 680                        die("Bogus regex in service table: %s", c->pattern);
 681                if (!regexec(&re, dir, 1, out, 0)) {
 682                        size_t n;
 683
 684                        if (strcmp(method, c->method))
 685                                return bad_request(&hdr, c);
 686
 687                        cmd = c;
 688                        n = out[0].rm_eo - out[0].rm_so;
 689                        cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
 690                        dir[out[0].rm_so] = 0;
 691                        break;
 692                }
 693                regfree(&re);
 694        }
 695
 696        if (!cmd)
 697                not_found(&hdr, "Request not supported: '%s'", dir);
 698
 699        setup_path();
 700        if (!enter_repo(dir, 0))
 701                not_found(&hdr, "Not a git repository: '%s'", dir);
 702        if (!getenv("GIT_HTTP_EXPORT_ALL") &&
 703            access("git-daemon-export-ok", F_OK) )
 704                not_found(&hdr, "Repository not exported: '%s'", dir);
 705
 706        http_config();
 707        max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER",
 708                                           max_request_buffer);
 709
 710        cmd->imp(&hdr, cmd_arg);
 711        return 0;
 712}