Andrew's git - gitweb.git/blob

   1/*
   2 * Copyright (c) 2005, 2006 Rene Scharfe
   3 */
   4#include "cache.h"
   5#include "config.h"
   6#include "tar.h"
   7#include "archive.h"
   8#include "object-store.h"
   9#include "streaming.h"
  10#include "run-command.h"
  11
  12#define RECORDSIZE      (512)
  13#define BLOCKSIZE       (RECORDSIZE * 20)
  14
  15static char block[BLOCKSIZE];
  16static unsigned long offset;
  17
  18static int tar_umask = 002;
  19
  20static int write_tar_filter_archive(const struct archiver *ar,
  21                                    struct archiver_args *args);
  22
  23/*
  24 * This is the max value that a ustar size header can specify, as it is fixed
  25 * at 11 octal digits. POSIX specifies that we switch to extended headers at
  26 * this size.
  27 *
  28 * Likewise for the mtime (which happens to use a buffer of the same size).
  29 */
  30#if ULONG_MAX == 0xFFFFFFFF
  31#define USTAR_MAX_SIZE ULONG_MAX
  32#else
  33#define USTAR_MAX_SIZE 077777777777UL
  34#endif
  35#if TIME_MAX == 0xFFFFFFFF
  36#define USTAR_MAX_MTIME TIME_MAX
  37#else
  38#define USTAR_MAX_MTIME 077777777777ULL
  39#endif
  40
  41/* writes out the whole block, but only if it is full */
  42static void write_if_needed(void)
  43{
  44        if (offset == BLOCKSIZE) {
  45                write_or_die(1, block, BLOCKSIZE);
  46                offset = 0;
  47        }
  48}
  49
  50/*
  51 * queues up writes, so that all our write(2) calls write exactly one
  52 * full block; pads writes to RECORDSIZE
  53 */
  54static void do_write_blocked(const void *data, unsigned long size)
  55{
  56        const char *buf = data;
  57
  58        if (offset) {
  59                unsigned long chunk = BLOCKSIZE - offset;
  60                if (size < chunk)
  61                        chunk = size;
  62                memcpy(block + offset, buf, chunk);
  63                size -= chunk;
  64                offset += chunk;
  65                buf += chunk;
  66                write_if_needed();
  67        }
  68        while (size >= BLOCKSIZE) {
  69                write_or_die(1, buf, BLOCKSIZE);
  70                size -= BLOCKSIZE;
  71                buf += BLOCKSIZE;
  72        }
  73        if (size) {
  74                memcpy(block + offset, buf, size);
  75                offset += size;
  76        }
  77}
  78
  79static void finish_record(void)
  80{
  81        unsigned long tail;
  82        tail = offset % RECORDSIZE;
  83        if (tail)  {
  84                memset(block + offset, 0, RECORDSIZE - tail);
  85                offset += RECORDSIZE - tail;
  86        }
  87        write_if_needed();
  88}
  89
  90static void write_blocked(const void *data, unsigned long size)
  91{
  92        do_write_blocked(data, size);
  93        finish_record();
  94}
  95
  96/*
  97 * The end of tar archives is marked by 2*512 nul bytes and after that
  98 * follows the rest of the block (if any).
  99 */
 100static void write_trailer(void)
 101{
 102        int tail = BLOCKSIZE - offset;
 103        memset(block + offset, 0, tail);
 104        write_or_die(1, block, BLOCKSIZE);
 105        if (tail < 2 * RECORDSIZE) {
 106                memset(block, 0, offset);
 107                write_or_die(1, block, BLOCKSIZE);
 108        }
 109}
 110
 111/*
 112 * queues up writes, so that all our write(2) calls write exactly one
 113 * full block; pads writes to RECORDSIZE
 114 */
 115static int stream_blocked(const struct object_id *oid)
 116{
 117        struct git_istream *st;
 118        enum object_type type;
 119        unsigned long sz;
 120        char buf[BLOCKSIZE];
 121        ssize_t readlen;
 122
 123        st = open_istream(oid, &type, &sz, NULL);
 124        if (!st)
 125                return error(_("cannot stream blob %s"), oid_to_hex(oid));
 126        for (;;) {
 127                readlen = read_istream(st, buf, sizeof(buf));
 128                if (readlen <= 0)
 129                        break;
 130                do_write_blocked(buf, readlen);
 131        }
 132        close_istream(st);
 133        if (!readlen)
 134                finish_record();
 135        return readlen;
 136}
 137
 138/*
 139 * pax extended header records have the format "%u %s=%s\n".  %u contains
 140 * the size of the whole string (including the %u), the first %s is the
 141 * keyword, the second one is the value.  This function constructs such a
 142 * string and appends it to a struct strbuf.
 143 */
 144static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
 145                                     const char *value, unsigned int valuelen)
 146{
 147        int len, tmp;
 148
 149        /* "%u %s=%s\n" */
 150        len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
 151        for (tmp = len; tmp > 9; tmp /= 10)
 152                len++;
 153
 154        strbuf_grow(sb, len);
 155        strbuf_addf(sb, "%u %s=", len, keyword);
 156        strbuf_add(sb, value, valuelen);
 157        strbuf_addch(sb, '\n');
 158}
 159
 160/*
 161 * Like strbuf_append_ext_header, but for numeric values.
 162 */
 163static void strbuf_append_ext_header_uint(struct strbuf *sb,
 164                                          const char *keyword,
 165                                          uintmax_t value)
 166{
 167        char buf[40]; /* big enough for 2^128 in decimal, plus NUL */
 168        int len;
 169
 170        len = xsnprintf(buf, sizeof(buf), "%"PRIuMAX, value);
 171        strbuf_append_ext_header(sb, keyword, buf, len);
 172}
 173
 174static unsigned int ustar_header_chksum(const struct ustar_header *header)
 175{
 176        const unsigned char *p = (const unsigned char *)header;
 177        unsigned int chksum = 0;
 178        while (p < (const unsigned char *)header->chksum)
 179                chksum += *p++;
 180        chksum += sizeof(header->chksum) * ' ';
 181        p += sizeof(header->chksum);
 182        while (p < (const unsigned char *)header + sizeof(struct ustar_header))
 183                chksum += *p++;
 184        return chksum;
 185}
 186
 187static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen)
 188{
 189        size_t i = pathlen;
 190        if (i > 1 && path[i - 1] == '/')
 191                i--;
 192        if (i > maxlen)
 193                i = maxlen;
 194        do {
 195                i--;
 196        } while (i > 0 && path[i] != '/');
 197        return i;
 198}
 199
 200static void prepare_header(struct archiver_args *args,
 201                           struct ustar_header *header,
 202                           unsigned int mode, unsigned long size)
 203{
 204        xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777);
 205        xsnprintf(header->size, sizeof(header->size), "%011"PRIoMAX , S_ISREG(mode) ? (uintmax_t)size : (uintmax_t)0);
 206        xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time);
 207
 208        xsnprintf(header->uid, sizeof(header->uid), "%07o", 0);
 209        xsnprintf(header->gid, sizeof(header->gid), "%07o", 0);
 210        strlcpy(header->uname, "root", sizeof(header->uname));
 211        strlcpy(header->gname, "root", sizeof(header->gname));
 212        xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0);
 213        xsnprintf(header->devminor, sizeof(header->devminor), "%07o", 0);
 214
 215        memcpy(header->magic, "ustar", 6);
 216        memcpy(header->version, "00", 2);
 217
 218        xsnprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header));
 219}
 220
 221static void write_extended_header(struct archiver_args *args,
 222                                  const struct object_id *oid,
 223                                  const void *buffer, unsigned long size)
 224{
 225        struct ustar_header header;
 226        unsigned int mode;
 227        memset(&header, 0, sizeof(header));
 228        *header.typeflag = TYPEFLAG_EXT_HEADER;
 229        mode = 0100666;
 230        xsnprintf(header.name, sizeof(header.name), "%s.paxheader", oid_to_hex(oid));
 231        prepare_header(args, &header, mode, size);
 232        write_blocked(&header, sizeof(header));
 233        write_blocked(buffer, size);
 234}
 235
 236static int write_tar_entry(struct archiver_args *args,
 237                           const struct object_id *oid,
 238                           const char *path, size_t pathlen,
 239                           unsigned int mode)
 240{
 241        struct ustar_header header;
 242        struct strbuf ext_header = STRBUF_INIT;
 243        unsigned int old_mode = mode;
 244        unsigned long size, size_in_header;
 245        void *buffer;
 246        int err = 0;
 247
 248        memset(&header, 0, sizeof(header));
 249
 250        if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 251                *header.typeflag = TYPEFLAG_DIR;
 252                mode = (mode | 0777) & ~tar_umask;
 253        } else if (S_ISLNK(mode)) {
 254                *header.typeflag = TYPEFLAG_LNK;
 255                mode |= 0777;
 256        } else if (S_ISREG(mode)) {
 257                *header.typeflag = TYPEFLAG_REG;
 258                mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 259        } else {
 260                return error(_("unsupported file mode: 0%o (SHA1: %s)"),
 261                             mode, oid_to_hex(oid));
 262        }
 263        if (pathlen > sizeof(header.name)) {
 264                size_t plen = get_path_prefix(path, pathlen,
 265                                              sizeof(header.prefix));
 266                size_t rest = pathlen - plen - 1;
 267                if (plen > 0 && rest <= sizeof(header.name)) {
 268                        memcpy(header.prefix, path, plen);
 269                        memcpy(header.name, path + plen + 1, rest);
 270                } else {
 271                        xsnprintf(header.name, sizeof(header.name), "%s.data",
 272                                  oid_to_hex(oid));
 273                        strbuf_append_ext_header(&ext_header, "path",
 274                                                 path, pathlen);
 275                }
 276        } else
 277                memcpy(header.name, path, pathlen);
 278
 279        if (S_ISREG(mode) && !args->convert &&
 280            oid_object_info(args->repo, oid, &size) == OBJ_BLOB &&
 281            size > big_file_threshold)
 282                buffer = NULL;
 283        else if (S_ISLNK(mode) || S_ISREG(mode)) {
 284                enum object_type type;
 285                buffer = object_file_to_archive(args, path, oid, old_mode, &type, &size);
 286                if (!buffer)
 287                        return error(_("cannot read %s"), oid_to_hex(oid));
 288        } else {
 289                buffer = NULL;
 290                size = 0;
 291        }
 292
 293        if (S_ISLNK(mode)) {
 294                if (size > sizeof(header.linkname)) {
 295                        xsnprintf(header.linkname, sizeof(header.linkname),
 296                                  "see %s.paxheader", oid_to_hex(oid));
 297                        strbuf_append_ext_header(&ext_header, "linkpath",
 298                                                 buffer, size);
 299                } else
 300                        memcpy(header.linkname, buffer, size);
 301        }
 302
 303        size_in_header = size;
 304        if (S_ISREG(mode) && size > USTAR_MAX_SIZE) {
 305                size_in_header = 0;
 306                strbuf_append_ext_header_uint(&ext_header, "size", size);
 307        }
 308
 309        prepare_header(args, &header, mode, size_in_header);
 310
 311        if (ext_header.len > 0) {
 312                write_extended_header(args, oid, ext_header.buf,
 313                                      ext_header.len);
 314        }
 315        strbuf_release(&ext_header);
 316        write_blocked(&header, sizeof(header));
 317        if (S_ISREG(mode) && size > 0) {
 318                if (buffer)
 319                        write_blocked(buffer, size);
 320                else
 321                        err = stream_blocked(oid);
 322        }
 323        free(buffer);
 324        return err;
 325}
 326
 327static void write_global_extended_header(struct archiver_args *args)
 328{
 329        const unsigned char *sha1 = args->commit_sha1;
 330        struct strbuf ext_header = STRBUF_INIT;
 331        struct ustar_header header;
 332        unsigned int mode;
 333
 334        if (sha1)
 335                strbuf_append_ext_header(&ext_header, "comment",
 336                                         sha1_to_hex(sha1), 40);
 337        if (args->time > USTAR_MAX_MTIME) {
 338                strbuf_append_ext_header_uint(&ext_header, "mtime",
 339                                              args->time);
 340                args->time = USTAR_MAX_MTIME;
 341        }
 342
 343        if (!ext_header.len)
 344                return;
 345
 346        memset(&header, 0, sizeof(header));
 347        *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 348        mode = 0100666;
 349        xsnprintf(header.name, sizeof(header.name), "pax_global_header");
 350        prepare_header(args, &header, mode, ext_header.len);
 351        write_blocked(&header, sizeof(header));
 352        write_blocked(ext_header.buf, ext_header.len);
 353        strbuf_release(&ext_header);
 354}
 355
 356static struct archiver **tar_filters;
 357static int nr_tar_filters;
 358static int alloc_tar_filters;
 359
 360static struct archiver *find_tar_filter(const char *name, int len)
 361{
 362        int i;
 363        for (i = 0; i < nr_tar_filters; i++) {
 364                struct archiver *ar = tar_filters[i];
 365                if (!strncmp(ar->name, name, len) && !ar->name[len])
 366                        return ar;
 367        }
 368        return NULL;
 369}
 370
 371static int tar_filter_config(const char *var, const char *value, void *data)
 372{
 373        struct archiver *ar;
 374        const char *name;
 375        const char *type;
 376        int namelen;
 377
 378        if (parse_config_key(var, "tar", &name, &namelen, &type) < 0 || !name)
 379                return 0;
 380
 381        ar = find_tar_filter(name, namelen);
 382        if (!ar) {
 383                ar = xcalloc(1, sizeof(*ar));
 384                ar->name = xmemdupz(name, namelen);
 385                ar->write_archive = write_tar_filter_archive;
 386                ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS;
 387                ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
 388                tar_filters[nr_tar_filters++] = ar;
 389        }
 390
 391        if (!strcmp(type, "command")) {
 392                if (!value)
 393                        return config_error_nonbool(var);
 394                free(ar->data);
 395                ar->data = xstrdup(value);
 396                return 0;
 397        }
 398        if (!strcmp(type, "remote")) {
 399                if (git_config_bool(var, value))
 400                        ar->flags |= ARCHIVER_REMOTE;
 401                else
 402                        ar->flags &= ~ARCHIVER_REMOTE;
 403                return 0;
 404        }
 405
 406        return 0;
 407}
 408
 409static int git_tar_config(const char *var, const char *value, void *cb)
 410{
 411        if (!strcmp(var, "tar.umask")) {
 412                if (value && !strcmp(value, "user")) {
 413                        tar_umask = umask(0);
 414                        umask(tar_umask);
 415                } else {
 416                        tar_umask = git_config_int(var, value);
 417                }
 418                return 0;
 419        }
 420
 421        return tar_filter_config(var, value, cb);
 422}
 423
 424static int write_tar_archive(const struct archiver *ar,
 425                             struct archiver_args *args)
 426{
 427        int err = 0;
 428
 429        write_global_extended_header(args);
 430        err = write_archive_entries(args, write_tar_entry);
 431        if (!err)
 432                write_trailer();
 433        return err;
 434}
 435
 436static int write_tar_filter_archive(const struct archiver *ar,
 437                                    struct archiver_args *args)
 438{
 439        struct strbuf cmd = STRBUF_INIT;
 440        struct child_process filter = CHILD_PROCESS_INIT;
 441        const char *argv[2];
 442        int r;
 443
 444        if (!ar->data)
 445                BUG("tar-filter archiver called with no filter defined");
 446
 447        strbuf_addstr(&cmd, ar->data);
 448        if (args->compression_level >= 0)
 449                strbuf_addf(&cmd, " -%d", args->compression_level);
 450
 451        argv[0] = cmd.buf;
 452        argv[1] = NULL;
 453        filter.argv = argv;
 454        filter.use_shell = 1;
 455        filter.in = -1;
 456
 457        if (start_command(&filter) < 0)
 458                die_errno(_("unable to start '%s' filter"), argv[0]);
 459        close(1);
 460        if (dup2(filter.in, 1) < 0)
 461                die_errno(_("unable to redirect descriptor"));
 462        close(filter.in);
 463
 464        r = write_tar_archive(ar, args);
 465
 466        close(1);
 467        if (finish_command(&filter) != 0)
 468                die(_("'%s' filter reported error"), argv[0]);
 469
 470        strbuf_release(&cmd);
 471        return r;
 472}
 473
 474static struct archiver tar_archiver = {
 475        "tar",
 476        write_tar_archive,
 477        ARCHIVER_REMOTE
 478};
 479
 480void init_tar_archiver(void)
 481{
 482        int i;
 483        register_archiver(&tar_archiver);
 484
 485        tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
 486        tar_filter_config("tar.tgz.remote", "true", NULL);
 487        tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
 488        tar_filter_config("tar.tar.gz.remote", "true", NULL);
 489        git_config(git_tar_config, NULL);
 490        for (i = 0; i < nr_tar_filters; i++) {
 491                /* omit any filters that never had a command configured */
 492                if (tar_filters[i]->data)
 493                        register_archiver(tar_filters[i]);
 494        }
 495}