Dogcows Code - chaz/tar/blob - src/common.h

   1 /* Common declarations for the tar program.
   2
   3    Copyright (C) 1988, 1992, 1993, 1994, 1996, 1997, 1999, 2000, 2001,
   4    2003 Free Software Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by the
   8    Free Software Foundation; either version 2, or (at your option) any later
   9    version.
  10
  11    This program is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
  14    Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License along
  17    with this program; if not, write to the Free Software Foundation, Inc.,
  18    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 /* Declare the GNU tar archive format.  */
  21 #include "tar.h"
  22
  23 /* The checksum field is filled with this while the checksum is computed.  */
  24 #define CHKBLANKS       "        "      /* 8 blanks, no null */
  25
  26 /* Some constants from POSIX are given names.  */
  27 #define NAME_FIELD_SIZE   100
  28 #define PREFIX_FIELD_SIZE 155
  29 #define UNAME_FIELD_SIZE   32
  30 #define GNAME_FIELD_SIZE   32
  31
  32 /* FIXME */
  33 #define MAXOCTAL11      017777777777L
  34 #define MAXOCTAL7       07777777
  35
  36
  37 \f
  38 /* Some various global definitions.  */
  39
  40 /* Name of file to use for interacting with user.  */
  41 #if MSDOS
  42 # define TTY_NAME "con"
  43 #else
  44 # define TTY_NAME "/dev/tty"
  45 #endif
  46
  47 /* GLOBAL is defined to empty in tar.c only, and left alone in other *.c
  48    modules.  Here, we merely set it to "extern" if it is not already set.
  49    GNU tar does depend on the system loader to preset all GLOBAL variables to
  50    neutral (or zero) values, explicit initialization is usually not done.  */
  51 #ifndef GLOBAL
  52 # define GLOBAL extern
  53 #endif
  54
  55 /* Exit status for GNU tar.  Let's try to keep this list as simple as
  56    possible.  -d option strongly invites a status different for unequal
  57    comparison and other errors.  */
  58 GLOBAL int exit_status;
  59
  60 #define TAREXIT_SUCCESS 0
  61 #define TAREXIT_DIFFERS 1
  62 #define TAREXIT_FAILURE 2
  63
  64 /* Both WARN and ERROR write a message on stderr and continue processing,
  65    however ERROR manages so tar will exit unsuccessfully.  FATAL_ERROR
  66    writes a message on stderr and aborts immediately, with another message
  67    line telling so.  USAGE_ERROR works like FATAL_ERROR except that the
  68    other message line suggests trying --help.  All four macros accept a
  69    single argument of the form ((0, errno, _("FORMAT"), Args...)).  errno
  70    is zero when the error is not being detected by the system.  */
  71
  72 #define WARN(Args) \
  73   error Args
  74 #define ERROR(Args) \
  75   (error Args, exit_status = TAREXIT_FAILURE)
  76 #define FATAL_ERROR(Args) \
  77   (error Args, fatal_exit ())
  78 #define USAGE_ERROR(Args) \
  79   (error Args, usage (TAREXIT_FAILURE))
  80 \f
  81 #include "arith.h"
  82 #include <backupfile.h>
  83 #include <exclude.h>
  84 #include <full-write.h>
  85 #include <modechange.h>
  86 #include <quote.h>
  87 #include <safe-read.h>
  88
  89 /* Log base 2 of common values.  */
  90 #define LG_8 3
  91 #define LG_64 6
  92 #define LG_256 8
  93 \f
  94 /* Information gleaned from the command line.  */
  95
  96 /* Name of this program.  */
  97 GLOBAL const char *program_name;
  98
  99 /* Main command option.  */
 100
 101 enum subcommand
 102 {
 103   UNKNOWN_SUBCOMMAND,           /* none of the following */
 104   APPEND_SUBCOMMAND,            /* -r */
 105   CAT_SUBCOMMAND,               /* -A */
 106   CREATE_SUBCOMMAND,            /* -c */
 107   DELETE_SUBCOMMAND,            /* -D */
 108   DIFF_SUBCOMMAND,              /* -d */
 109   EXTRACT_SUBCOMMAND,           /* -x */
 110   LIST_SUBCOMMAND,              /* -t */
 111   UPDATE_SUBCOMMAND             /* -u */
 112 };
 113
 114 GLOBAL enum subcommand subcommand_option;
 115
 116 /* Selected format for output archive.  */
 117 GLOBAL enum archive_format archive_format;
 118
 119 /* Either NL or NUL, as decided by the --null option.  */
 120 GLOBAL char filename_terminator;
 121
 122 /* Size of each record, once in blocks, once in bytes.  Those two variables
 123    are always related, the second being BLOCKSIZE times the first.  They do
 124    not have _option in their name, even if their values is derived from
 125    option decoding, as these are especially important in tar.  */
 126 GLOBAL int blocking_factor;
 127 GLOBAL size_t record_size;
 128
 129 GLOBAL bool absolute_names_option;
 130
 131 /* This variable tells how to interpret newer_mtime_option, below.  If zero,
 132    files get archived if their mtime is not less than newer_mtime_option.
 133    If nonzero, files get archived if *either* their ctime or mtime is not less
 134    than newer_mtime_option.  */
 135 GLOBAL int after_date_option;
 136
 137 GLOBAL bool atime_preserve_option;
 138
 139 GLOBAL bool backup_option;
 140
 141 /* Type of backups being made.  */
 142 GLOBAL enum backup_type backup_type;
 143
 144 GLOBAL bool block_number_option;
 145
 146 GLOBAL bool checkpoint_option;
 147
 148 /* Specified name of compression program, or "gzip" as implied by -z.  */
 149 GLOBAL const char *use_compress_program_option;
 150
 151 GLOBAL bool dereference_option;
 152
 153 /* Print a message if not all links are dumped */
 154 GLOBAL int check_links_option;
 155
 156 /* Patterns that match file names to be excluded.  */
 157 GLOBAL struct exclude *excluded;
 158
 159 /* Specified file containing names to work on.  */
 160 GLOBAL const char *files_from_option;
 161
 162 GLOBAL bool force_local_option;
 163
 164 /* Specified value to be put into tar file in place of stat () results, or
 165    just -1 if such an override should not take place.  */
 166 GLOBAL gid_t group_option;
 167
 168 GLOBAL bool ignore_failed_read_option;
 169
 170 GLOBAL bool ignore_zeros_option;
 171
 172 GLOBAL bool incremental_option;
 173
 174 /* Specified name of script to run at end of each tape change.  */
 175 GLOBAL const char *info_script_option;
 176
 177 GLOBAL bool interactive_option;
 178
 179 /* If nonzero, extract only Nth occurrence of each named file */
 180 GLOBAL uintmax_t occurrence_option;
 181
 182 enum old_files
 183 {
 184   DEFAULT_OLD_FILES, /* default */
 185   NO_OVERWRITE_DIR_OLD_FILES, /* --no-overwrite-dir */
 186   OVERWRITE_OLD_FILES, /* --overwrite */
 187   UNLINK_FIRST_OLD_FILES, /* --unlink-first */
 188   KEEP_OLD_FILES /* --keep-old-files */
 189 };
 190 GLOBAL enum old_files old_files_option;
 191
 192 /* Specified file name for incremental list.  */
 193 GLOBAL const char *listed_incremental_option;
 194
 195 /* Specified mode change string.  */
 196 GLOBAL struct mode_change *mode_option;
 197
 198 GLOBAL bool multi_volume_option;
 199
 200 /* The same variable hold the time, whether mtime or ctime.  Just fake a
 201    non-existing option, for making the code clearer, elsewhere.  */
 202 #define newer_ctime_option newer_mtime_option
 203
 204 /* Specified threshold date and time.  Files having an older time stamp
 205    do not get archived (also see after_date_option above).  */
 206 GLOBAL time_t newer_mtime_option;
 207
 208 /* Zero if there is no recursion, otherwise FNM_LEADING_DIR.  */
 209 GLOBAL int recursion_option;
 210
 211 GLOBAL bool numeric_owner_option;
 212
 213 GLOBAL bool one_file_system_option;
 214
 215 /* Specified value to be put into tar file in place of stat () results, or
 216    just -1 if such an override should not take place.  */
 217 GLOBAL uid_t owner_option;
 218
 219 GLOBAL bool recursive_unlink_option;
 220
 221 GLOBAL bool read_full_records_option;
 222
 223 GLOBAL bool remove_files_option;
 224
 225 /* Specified remote shell command.  */
 226 GLOBAL const char *rsh_command_option;
 227
 228 GLOBAL bool same_order_option;
 229
 230 /* If positive, preserve ownership when extracting.  */
 231 GLOBAL int same_owner_option;
 232
 233 /* If positive, preserve permissions when extracting.  */
 234 GLOBAL int same_permissions_option;
 235
 236 /* When set, strip the given number of path elements from the file name
 237    before extracting */
 238 GLOBAL size_t strip_path_elements;
 239
 240 GLOBAL bool show_omitted_dirs_option;
 241
 242 GLOBAL bool sparse_option;
 243
 244 GLOBAL bool starting_file_option;
 245
 246 /* Specified maximum byte length of each tape volume (multiple of 1024).  */
 247 GLOBAL tarlong tape_length_option;
 248
 249 GLOBAL bool to_stdout_option;
 250
 251 GLOBAL bool totals_option;
 252
 253 GLOBAL bool touch_option;
 254
 255 /* Count how many times the option has been set, multiple setting yields
 256    more verbose behavior.  Value 0 means no verbosity, 1 means file name
 257    only, 2 means file name and all attributes.  More than 2 is just like 2.  */
 258 GLOBAL int verbose_option;
 259
 260 GLOBAL bool verify_option;
 261
 262 /* Specified name of file containing the volume number.  */
 263 GLOBAL const char *volno_file_option;
 264
 265 /* Specified value or pattern.  */
 266 GLOBAL const char *volume_label_option;
 267 \f
 268 /* Other global variables.  */
 269
 270 /* File descriptor for archive file.  */
 271 GLOBAL int archive;
 272
 273 /* Nonzero when outputting to /dev/null.  */
 274 GLOBAL bool dev_null_output;
 275
 276 /* Timestamp for when we started execution.  */
 277 #if HAVE_CLOCK_GETTIME
 278   GLOBAL struct timespec start_timespec;
 279 # define start_time (start_timespec.tv_sec)
 280 #else
 281   GLOBAL time_t start_time;
 282 #endif
 283
 284 GLOBAL struct tar_stat_info current_stat_info;
 285
 286 /* List of tape drive names, number of such tape drives, allocated number,
 287    and current cursor in list.  */
 288 GLOBAL const char **archive_name_array;
 289 GLOBAL int archive_names;
 290 GLOBAL int allocated_archive_names;
 291 GLOBAL const char **archive_name_cursor;
 292
 293 /* Output index file name.  */
 294 GLOBAL char const *index_file_name;
 295
 296 /* Structure for keeping track of filenames and lists thereof.  */
 297 struct name
 298   {
 299     struct name *next;
 300     size_t length;              /* cached strlen(name) */
 301     uintmax_t found_count;      /* number of times a matching file has
 302                                    been found */
 303     int isdir;
 304     char firstch;               /* first char is literally matched */
 305     char regexp;                /* this name is a regexp, not literal */
 306     int change_dir;             /* set with the -C option */
 307     char const *dir_contents;   /* for incremental_option */
 308     char fake;                  /* dummy entry */
 309     char name[1];
 310   };
 311
 312 /* Obnoxious test to see if dimwit is trying to dump the archive.  */
 313 GLOBAL dev_t ar_dev;
 314 GLOBAL ino_t ar_ino;
 315
 316 \f
 317 /* Declarations for each module.  */
 318
 319 /* FIXME: compare.c should not directly handle the following variable,
 320    instead, this should be done in buffer.c only.  */
 321
 322 enum access_mode
 323 {
 324   ACCESS_READ,
 325   ACCESS_WRITE,
 326   ACCESS_UPDATE
 327 };
 328 extern enum access_mode access_mode;
 329
 330 /* Module buffer.c.  */
 331
 332 extern FILE *stdlis;
 333 extern char *save_name;
 334 extern off_t save_sizeleft;
 335 extern off_t save_totsize;
 336 extern bool write_archive_to_stdout;
 337
 338 size_t available_space_after (union block *);
 339 off_t current_block_ordinal (void);
 340 void close_archive (void);
 341 void closeout_volume_number (void);
 342 union block *find_next_block (void);
 343 void flush_read (void);
 344 void flush_write (void);
 345 void flush_archive (void);
 346 void init_volume_number (void);
 347 void open_archive (enum access_mode);
 348 void print_total_written (void);
 349 void reset_eof (void);
 350 void set_next_block_after (union block *);
 351 void clear_read_error_count (void);
 352 void xclose (int fd);
 353 void archive_write_error (ssize_t) __attribute__ ((noreturn));
 354 void archive_read_error (void);
 355
 356 /* Module create.c.  */
 357
 358 enum dump_status
 359   {
 360     dump_status_ok,
 361     dump_status_short,
 362     dump_status_fail,
 363     dump_status_not_implemented
 364   };
 365
 366 bool file_dumpable_p (struct tar_stat_info *stat);
 367 void create_archive (void);
 368 void pad_archive (off_t size_left);
 369 void dump_file (char *, int, dev_t);
 370 union block *start_header (struct tar_stat_info *st);
 371 void finish_header (struct tar_stat_info *, union block *, off_t);
 372 void write_eot (void);
 373 void check_links (void);
 374
 375 #define GID_TO_CHARS(val, where) gid_to_chars (val, where, sizeof (where))
 376 #define MAJOR_TO_CHARS(val, where) major_to_chars (val, where, sizeof (where))
 377 #define MINOR_TO_CHARS(val, where) minor_to_chars (val, where, sizeof (where))
 378 #define MODE_TO_CHARS(val, where) mode_to_chars (val, where, sizeof (where))
 379 #define OFF_TO_CHARS(val, where) off_to_chars (val, where, sizeof (where))
 380 #define SIZE_TO_CHARS(val, where) size_to_chars (val, where, sizeof (where))
 381 #define TIME_TO_CHARS(val, where) time_to_chars (val, where, sizeof (where))
 382 #define UID_TO_CHARS(val, where) uid_to_chars (val, where, sizeof (where))
 383 #define UINTMAX_TO_CHARS(val, where) uintmax_to_chars (val, where, sizeof (where))
 384 #define UNAME_TO_CHARS(name,buf) string_to_chars (name, buf, sizeof(buf))
 385 #define GNAME_TO_CHARS(name,buf) string_to_chars (name, buf, sizeof(buf))
 386
 387 void gid_to_chars (gid_t, char *, size_t);
 388 void major_to_chars (major_t, char *, size_t);
 389 void minor_to_chars (minor_t, char *, size_t);
 390 void mode_to_chars (mode_t, char *, size_t);
 391 void off_to_chars (off_t, char *, size_t);
 392 void size_to_chars (size_t, char *, size_t);
 393 void time_to_chars (time_t, char *, size_t);
 394 void uid_to_chars (uid_t, char *, size_t);
 395 void uintmax_to_chars (uintmax_t, char *, size_t);
 396 void string_to_chars (char *, char *, size_t);
 397
 398 /* Module diffarch.c.  */
 399
 400 extern bool now_verifying;
 401
 402 void diff_archive (void);
 403 void diff_init (void);
 404 void verify_volume (void);
 405
 406 /* Module extract.c.  */
 407
 408 extern bool we_are_root;
 409 void extr_init (void);
 410 void extract_archive (void);
 411 void extract_finish (void);
 412 void fatal_exit (void) __attribute__ ((noreturn));
 413
 414 /* Module delete.c.  */
 415
 416 void delete_archive_members (void);
 417
 418 /* Module incremen.c.  */
 419
 420 char *get_directory_contents (char *, dev_t);
 421 void read_directory_file (void);
 422 void write_directory_file (void);
 423 void gnu_restore (char const *);
 424
 425 /* Module list.c.  */
 426
 427 enum read_header
 428 {
 429   HEADER_STILL_UNREAD,          /* for when read_header has not been called */
 430   HEADER_SUCCESS,               /* header successfully read and checksummed */
 431   HEADER_SUCCESS_EXTENDED,      /* likewise, but we got an extended header */
 432   HEADER_ZERO_BLOCK,            /* zero block where header expected */
 433   HEADER_END_OF_FILE,           /* true end of file while header expected */
 434   HEADER_FAILURE                /* ill-formed header, or bad checksum */
 435 };
 436
 437 struct xheader
 438 {
 439   struct obstack *stk;
 440   size_t size;
 441   char *buffer;
 442 };
 443
 444 GLOBAL struct xheader extended_header;
 445 extern union block *current_header;
 446 extern enum archive_format current_format;
 447 extern size_t recent_long_name_blocks;
 448 extern size_t recent_long_link_blocks;
 449
 450 void decode_header (union block *, struct tar_stat_info *,
 451                     enum archive_format *, int);
 452 #define STRINGIFY_BIGINT(i, b) \
 453   stringify_uintmax_t_backwards ((uintmax_t) (i), (b) + UINTMAX_STRSIZE_BOUND)
 454 char *stringify_uintmax_t_backwards (uintmax_t, char *);
 455 char const *tartime (time_t);
 456
 457 #define GID_FROM_HEADER(where) gid_from_header (where, sizeof (where))
 458 #define MAJOR_FROM_HEADER(where) major_from_header (where, sizeof (where))
 459 #define MINOR_FROM_HEADER(where) minor_from_header (where, sizeof (where))
 460 #define MODE_FROM_HEADER(where) mode_from_header (where, sizeof (where))
 461 #define OFF_FROM_HEADER(where) off_from_header (where, sizeof (where))
 462 #define SIZE_FROM_HEADER(where) size_from_header (where, sizeof (where))
 463 #define TIME_FROM_HEADER(where) time_from_header (where, sizeof (where))
 464 #define UID_FROM_HEADER(where) uid_from_header (where, sizeof (where))
 465 #define UINTMAX_FROM_HEADER(where) uintmax_from_header (where, sizeof (where))
 466
 467 gid_t gid_from_header (const char *, size_t);
 468 major_t major_from_header (const char *, size_t);
 469 minor_t minor_from_header (const char *, size_t);
 470 mode_t mode_from_header (const char *, size_t);
 471 off_t off_from_header (const char *, size_t);
 472 size_t size_from_header (const char *, size_t);
 473 time_t time_from_header (const char *, size_t);
 474 uid_t uid_from_header (const char *, size_t);
 475 uintmax_t uintmax_from_header (const char *, size_t);
 476
 477 void list_archive (void);
 478 void print_for_mkdir (char *, int, mode_t);
 479 void print_header (struct tar_stat_info *, off_t);
 480 void read_and (void (*) (void));
 481 enum read_header read_header (bool);
 482 void skip_file (off_t);
 483 void skip_member (void);
 484
 485 /* Module mangle.c.  */
 486
 487 void extract_mangle (void);
 488
 489 /* Module misc.c.  */
 490
 491 void assign_string (char **, const char *);
 492 char *quote_copy_string (const char *);
 493 int unquote_string (char *);
 494
 495 size_t dot_dot_prefix_len (char const *);
 496
 497 enum remove_option
 498 {
 499   ORDINARY_REMOVE_OPTION,
 500   RECURSIVE_REMOVE_OPTION,
 501   WANT_DIRECTORY_REMOVE_OPTION
 502 };
 503 int remove_any_file (const char *, enum remove_option);
 504 int maybe_backup_file (const char *, int);
 505 void undo_last_backup (void);
 506
 507 int deref_stat (bool, char const *, struct stat *);
 508
 509 int chdir_arg (char const *);
 510 void chdir_do (int);
 511
 512 void decode_mode (mode_t, char *);
 513
 514 void chdir_fatal (char const *) __attribute__ ((noreturn));
 515 void chmod_error_details (char const *, mode_t);
 516 void chown_error_details (char const *, uid_t, gid_t);
 517 void close_error (char const *);
 518 void close_warn (char const *);
 519 void close_diag (char const *name);
 520 void exec_fatal (char const *) __attribute__ ((noreturn));
 521 void link_error (char const *, char const *);
 522 void mkdir_error (char const *);
 523 void mkfifo_error (char const *);
 524 void mknod_error (char const *);
 525 void open_error (char const *);
 526 void open_fatal (char const *) __attribute__ ((noreturn));
 527 void open_warn (char const *);
 528 void open_diag (char const *name);
 529 void read_error (char const *);
 530 void read_error_details (char const *, off_t, size_t);
 531 void read_fatal (char const *) __attribute__ ((noreturn));
 532 void read_fatal_details (char const *, off_t, size_t);
 533 void read_warn_details (char const *, off_t, size_t);
 534 void read_diag_details (char const *name, off_t offset, size_t size);
 535 void readlink_error (char const *);
 536 void readlink_warn (char const *);
 537 void readlink_diag (char const *name);
 538 void savedir_error (char const *);
 539 void savedir_warn (char const *);
 540 void savedir_diag (char const *name);
 541 void seek_error (char const *);
 542 void seek_error_details (char const *, off_t);
 543 void seek_warn (char const *);
 544 void seek_warn_details (char const *, off_t);
 545 void seek_diag_details (char const *, off_t);
 546 void stat_error (char const *);
 547 void stat_warn (char const *);
 548 void stat_diag (char const *name);
 549 void symlink_error (char const *, char const *);
 550 void truncate_error (char const *);
 551 void truncate_warn (char const *);
 552 void unlink_error (char const *);
 553 void utime_error (char const *);
 554 void waitpid_error (char const *);
 555 void write_error (char const *);
 556 void write_error_details (char const *, ssize_t, size_t);
 557 void write_fatal (char const *) __attribute__ ((noreturn));
 558 void write_fatal_details (char const *, ssize_t, size_t)
 559      __attribute__ ((noreturn));
 560
 561 pid_t xfork (void);
 562 void xpipe (int[2]);
 563
 564 /* Module names.c.  */
 565
 566 extern struct name *gnu_list_name;
 567
 568 void gid_to_gname (gid_t, char **gname);
 569 int gname_to_gid (char *gname, gid_t *);
 570 void uid_to_uname (uid_t, char **uname);
 571 int uname_to_uid (char *uname, uid_t *);
 572
 573 void init_names (void);
 574 void name_add (const char *);
 575 void name_init (int, char *const *);
 576 void name_term (void);
 577 char *name_next (int);
 578 void name_close (void);
 579 void name_gather (void);
 580 struct name *addname (char const *, int);
 581 int name_match (const char *);
 582 void names_notfound (void);
 583 void collect_and_sort_names (void);
 584 struct name *name_scan (const char *);
 585 char *name_from_list (void);
 586 void blank_name_list (void);
 587 char *new_name (const char *, const char *);
 588 char *safer_name_suffix (char const *, bool);
 589 size_t stripped_prefix_len (char const *file_name, size_t num);
 590 bool all_names_found (struct tar_stat_info *);
 591
 592 bool excluded_name (char const *);
 593
 594 void add_avoided_name (char const *);
 595 bool is_avoided_name (char const *);
 596
 597 bool contains_dot_dot (char const *);
 598
 599 #define ISFOUND(c) ((occurrence_option == 0) ? (c)->found_count : \
 600                     (c)->found_count == occurrence_option)
 601 #define WASFOUND(c) ((occurrence_option == 0) ? (c)->found_count : \
 602                      (c)->found_count >= occurrence_option)
 603
 604 /* Module tar.c.  */
 605
 606 int confirm (const char *, const char *);
 607 void request_stdin (const char *);
 608
 609 void tar_stat_init (struct tar_stat_info *st);
 610 void tar_stat_destroy (struct tar_stat_info *st);
 611
 612 /* Module update.c.  */
 613
 614 extern char *output_start;
 615
 616 void update_archive (void);
 617
 618 /* Module xheader.c.  */
 619
 620 void xheader_decode (struct tar_stat_info *);
 621 void xheader_store (char const *, struct tar_stat_info const *);
 622 void xheader_read (union block *, size_t);
 623 void xheader_finish (struct xheader *);
 624 void xheader_destroy (struct xheader *);
 625
 626 /* Module system.c */
 627
 628 void sys_detect_dev_null_output (void);
 629 void sys_save_archive_dev_ino (void);
 630 void sys_drain_input_pipe (void);
 631 void sys_wait_for_child (pid_t);
 632 void sys_spawn_shell (void);
 633 bool sys_compare_uid (struct stat *a, struct stat *b);
 634 bool sys_compare_gid (struct stat *a, struct stat *b);
 635 bool sys_file_is_archive (struct tar_stat_info *p);
 636 bool sys_compare_links (struct stat *link_data, struct stat *stat_data);
 637 int sys_truncate (int fd);
 638 void sys_reset_uid_gid (void);
 639 pid_t sys_child_open_for_compress (void);
 640 pid_t sys_child_open_for_uncompress (void);
 641 ssize_t sys_write_archive_buffer (void);
 642 bool sys_get_archive_stat (void);
 643
 644 /* Module compare.c */
 645 void report_difference (struct tar_stat_info *st, const char *message, ...);
 646
 647 /* Module sparse.c */
 648 bool sparse_file_p (struct tar_stat_info *stat);
 649 enum dump_status sparse_dump_file (int fd, struct tar_stat_info *stat);
 650 enum dump_status sparse_extract_file (int fd, struct tar_stat_info *stat, off_t *size);
 651 bool sparse_diff_file (int fd, struct tar_stat_info *stat);