contrib/libarchive-2/libarchive/archive_entry.h

   1 /*-
   2  * Copyright (c) 2003-2007 Tim Kientzle
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  *
  25  * $FreeBSD: src/lib/libarchive/archive_entry.h,v 1.26 2008/03/14 23:00:53 kientzle Exp $
  26  */
  27
  28 #ifndef ARCHIVE_ENTRY_H_INCLUDED
  29 #define ARCHIVE_ENTRY_H_INCLUDED
  30
  31 /*
  32  * Note: archive_entry.h is for use outside of libarchive; the
  33  * configuration headers (config.h, archive_platform.h, etc.) are
  34  * purely internal.  Do NOT use HAVE_XXX configuration macros to
  35  * control the behavior of this header!  If you must conditionalize,
  36  * use predefined compiler and/or platform macros.
  37  */
  38
  39 #include <sys/types.h>
  40 #include <stddef.h>  /* for wchar_t */
  41 #include <time.h>
  42
  43 /* Get appropriate definitions of standard POSIX-style types. */
  44 /* These should match the types used in 'struct stat' */
  45 #ifdef _WIN32
  46 #define __LA_UID_T      unsigned int
  47 #define __LA_GID_T      unsigned int
  48 #define __LA_DEV_T      unsigned int
  49 #define __LA_MODE_T     unsigned short
  50 #else
  51 #include <unistd.h>
  52 #define __LA_UID_T      uid_t
  53 #define __LA_GID_T      gid_t
  54 #define __LA_DEV_T      dev_t
  55 #define __LA_MODE_T     mode_t
  56 #endif
  57
  58 /*
  59  * XXX Is this defined for all Windows compilers?  If so, in what
  60  * header?  It would be nice to remove the __LA_INO_T indirection and
  61  * just use plain ino_t everywhere.  Likewise for the other types just
  62  * above.
  63  */
  64 #define __LA_INO_T      ino_t
  65
  66
  67 /*
  68  * On Windows, define LIBARCHIVE_STATIC if you're building or using a
  69  * .lib.  The default here assumes you're building a DLL.  Only
  70  * libarchive source should ever define __LIBARCHIVE_BUILD.
  71  */
  72 #if ((defined __WIN32__) || (defined _WIN32)) && (!defined LIBARCHIVE_STATIC)
  73 # ifdef __LIBARCHIVE_BUILD
  74 #  ifdef __GNUC__
  75 #   define __LA_DECL    __attribute__((dllexport)) extern
  76 #  else
  77 #   define __LA_DECL    __declspec(dllexport)
  78 #  endif
  79 # else
  80 #  ifdef __GNUC__
  81 #   define __LA_DECL    __attribute__((dllimport)) extern
  82 #  else
  83 #   define __LA_DECL    __declspec(dllimport)
  84 #  endif
  85 # endif
  86 #else
  87 /* Static libraries on all platforms and shared libraries on non-Windows. */
  88 # define __LA_DECL
  89 #endif
  90
  91 #ifdef __cplusplus
  92 extern "C" {
  93 #endif
  94
  95 /*
  96  * Description of an archive entry.
  97  *
  98  * You can think of this as "struct stat" with some text fields added in.
  99  *
 100  * TODO: Add "comment", "charset", and possibly other entries that are
 101  * supported by "pax interchange" format.  However, GNU, ustar, cpio,
 102  * and other variants don't support these features, so they're not an
 103  * excruciatingly high priority right now.
 104  *
 105  * TODO: "pax interchange" format allows essentially arbitrary
 106  * key/value attributes to be attached to any entry.  Supporting
 107  * such extensions may make this library useful for special
 108  * applications (e.g., a package manager could attach special
 109  * package-management attributes to each entry).
 110  */
 111 struct archive_entry;
 112
 113 /*
 114  * File-type constants.  These are returned from archive_entry_filetype()
 115  * and passed to archive_entry_set_filetype().
 116  *
 117  * These values match S_XXX defines on every platform I've checked,
 118  * including Windows, AIX, Linux, Solaris, and BSD.  They're
 119  * (re)defined here because platforms generally don't define the ones
 120  * they don't support.  For example, Windows doesn't define S_IFLNK or
 121  * S_IFBLK.  Instead of having a mass of conditional logic and system
 122  * checks to define any S_XXX values that aren't supported locally,
 123  * I've just defined a new set of such constants so that
 124  * libarchive-based applications can manipulate and identify archive
 125  * entries properly even if the hosting platform can't store them on
 126  * disk.
 127  *
 128  * These values are also used directly within some portable formats,
 129  * such as cpio.  If you find a platform that varies from these, the
 130  * correct solution is to leave these alone and translate from these
 131  * portable values to platform-native values when entries are read from
 132  * or written to disk.
 133  */
 134 #define AE_IFMT         0170000
 135 #define AE_IFREG        0100000
 136 #define AE_IFLNK        0120000
 137 #define AE_IFSOCK       0140000
 138 #define AE_IFCHR        0020000
 139 #define AE_IFBLK        0060000
 140 #define AE_IFDIR        0040000
 141 #define AE_IFIFO        0010000
 142
 143 /*
 144  * Basic object manipulation
 145  */
 146
 147 __LA_DECL struct archive_entry  *archive_entry_clear(struct archive_entry *);
 148 /* The 'clone' function does a deep copy; all of the strings are copied too. */
 149 __LA_DECL struct archive_entry  *archive_entry_clone(struct archive_entry *);
 150 __LA_DECL void                   archive_entry_free(struct archive_entry *);
 151 __LA_DECL struct archive_entry  *archive_entry_new(void);
 152
 153 /*
 154  * Retrieve fields from an archive_entry.
 155  */
 156
 157 __LA_DECL time_t         archive_entry_atime(struct archive_entry *);
 158 __LA_DECL long           archive_entry_atime_nsec(struct archive_entry *);
 159 __LA_DECL time_t         archive_entry_ctime(struct archive_entry *);
 160 __LA_DECL long           archive_entry_ctime_nsec(struct archive_entry *);
 161 __LA_DECL dev_t          archive_entry_dev(struct archive_entry *);
 162 __LA_DECL dev_t          archive_entry_devmajor(struct archive_entry *);
 163 __LA_DECL dev_t          archive_entry_devminor(struct archive_entry *);
 164 __LA_DECL __LA_MODE_T    archive_entry_filetype(struct archive_entry *);
 165 __LA_DECL void           archive_entry_fflags(struct archive_entry *,
 166                             unsigned long * /* set */,
 167                             unsigned long * /* clear */);
 168 __LA_DECL const char    *archive_entry_fflags_text(struct archive_entry *);
 169 __LA_DECL __LA_GID_T     archive_entry_gid(struct archive_entry *);
 170 __LA_DECL const char    *archive_entry_gname(struct archive_entry *);
 171 __LA_DECL const wchar_t *archive_entry_gname_w(struct archive_entry *);
 172 __LA_DECL const char    *archive_entry_hardlink(struct archive_entry *);
 173 __LA_DECL const wchar_t *archive_entry_hardlink_w(struct archive_entry *);
 174 __LA_DECL __LA_INO_T     archive_entry_ino(struct archive_entry *);
 175 __LA_DECL __LA_MODE_T    archive_entry_mode(struct archive_entry *);
 176 __LA_DECL time_t         archive_entry_mtime(struct archive_entry *);
 177 __LA_DECL long           archive_entry_mtime_nsec(struct archive_entry *);
 178 __LA_DECL unsigned int   archive_entry_nlink(struct archive_entry *);
 179 __LA_DECL const char    *archive_entry_pathname(struct archive_entry *);
 180 __LA_DECL const wchar_t *archive_entry_pathname_w(struct archive_entry *);
 181 __LA_DECL dev_t          archive_entry_rdev(struct archive_entry *);
 182 __LA_DECL dev_t          archive_entry_rdevmajor(struct archive_entry *);
 183 __LA_DECL dev_t          archive_entry_rdevminor(struct archive_entry *);
 184 __LA_DECL const char    *archive_entry_sourcepath(struct archive_entry *);
 185 __LA_DECL int64_t        archive_entry_size(struct archive_entry *);
 186 __LA_DECL const char    *archive_entry_strmode(struct archive_entry *);
 187 __LA_DECL const char    *archive_entry_symlink(struct archive_entry *);
 188 __LA_DECL const wchar_t *archive_entry_symlink_w(struct archive_entry *);
 189 __LA_DECL __LA_UID_T     archive_entry_uid(struct archive_entry *);
 190 __LA_DECL const char    *archive_entry_uname(struct archive_entry *);
 191 __LA_DECL const wchar_t *archive_entry_uname_w(struct archive_entry *);
 192
 193 /*
 194  * Set fields in an archive_entry.
 195  *
 196  * Note that string 'set' functions do not copy the string, only the pointer.
 197  * In contrast, 'copy' functions do copy the object pointed to.
 198  */
 199
 200 __LA_DECL void  archive_entry_set_atime(struct archive_entry *, time_t, long);
 201 __LA_DECL void  archive_entry_set_ctime(struct archive_entry *, time_t, long);
 202 __LA_DECL void  archive_entry_set_dev(struct archive_entry *, dev_t);
 203 __LA_DECL void  archive_entry_set_devmajor(struct archive_entry *, dev_t);
 204 __LA_DECL void  archive_entry_set_devminor(struct archive_entry *, dev_t);
 205 __LA_DECL void  archive_entry_set_filetype(struct archive_entry *, unsigned int);
 206 __LA_DECL void  archive_entry_set_fflags(struct archive_entry *,
 207             unsigned long /* set */, unsigned long /* clear */);
 208 /* Returns pointer to start of first invalid token, or NULL if none. */
 209 /* Note that all recognized tokens are processed, regardless. */
 210 __LA_DECL const char *archive_entry_copy_fflags_text(struct archive_entry *,
 211             const char *);
 212 __LA_DECL const wchar_t *archive_entry_copy_fflags_text_w(struct archive_entry *,
 213             const wchar_t *);
 214 __LA_DECL void  archive_entry_set_gid(struct archive_entry *, __LA_GID_T);
 215 __LA_DECL void  archive_entry_set_gname(struct archive_entry *, const char *);
 216 __LA_DECL void  archive_entry_copy_gname(struct archive_entry *, const char *);
 217 __LA_DECL void  archive_entry_copy_gname_w(struct archive_entry *, const wchar_t *);
 218 __LA_DECL int   archive_entry_update_gname_utf8(struct archive_entry *, const char *);
 219 __LA_DECL void  archive_entry_set_hardlink(struct archive_entry *, const char *);
 220 __LA_DECL void  archive_entry_copy_hardlink(struct archive_entry *, const char *);
 221 __LA_DECL void  archive_entry_copy_hardlink_w(struct archive_entry *, const wchar_t *);
 222 __LA_DECL void  archive_entry_set_ino(struct archive_entry *, unsigned long);
 223 __LA_DECL void  archive_entry_set_link(struct archive_entry *, const char *);
 224 __LA_DECL void  archive_entry_copy_link(struct archive_entry *, const char *);
 225 __LA_DECL void  archive_entry_copy_link_w(struct archive_entry *, const wchar_t *);
 226 __LA_DECL int   archive_entry_update_link_utf8(struct archive_entry *, const char *);
 227 __LA_DECL void  archive_entry_set_mode(struct archive_entry *, __LA_MODE_T);
 228 __LA_DECL void  archive_entry_set_mtime(struct archive_entry *, time_t, long);
 229 __LA_DECL void  archive_entry_set_nlink(struct archive_entry *, unsigned int);
 230 __LA_DECL void  archive_entry_set_pathname(struct archive_entry *, const char *);
 231 __LA_DECL void  archive_entry_copy_pathname(struct archive_entry *, const char *);
 232 __LA_DECL void  archive_entry_copy_pathname_w(struct archive_entry *, const wchar_t *);
 233 __LA_DECL int   archive_entry_update_pathname_utf8(struct archive_entry *, const char *);
 234 __LA_DECL void  archive_entry_set_perm(struct archive_entry *, __LA_MODE_T);
 235 __LA_DECL void  archive_entry_set_rdev(struct archive_entry *, dev_t);
 236 __LA_DECL void  archive_entry_set_rdevmajor(struct archive_entry *, dev_t);
 237 __LA_DECL void  archive_entry_set_rdevminor(struct archive_entry *, dev_t);
 238 __LA_DECL void  archive_entry_set_size(struct archive_entry *, int64_t);
 239 __LA_DECL void  archive_entry_copy_sourcepath(struct archive_entry *, const char *);
 240 __LA_DECL void  archive_entry_set_symlink(struct archive_entry *, const char *);
 241 __LA_DECL void  archive_entry_copy_symlink(struct archive_entry *, const char *);
 242 __LA_DECL void  archive_entry_copy_symlink_w(struct archive_entry *, const wchar_t *);
 243 __LA_DECL void  archive_entry_set_uid(struct archive_entry *, __LA_UID_T);
 244 __LA_DECL void  archive_entry_set_uname(struct archive_entry *, const char *);
 245 __LA_DECL void  archive_entry_copy_uname(struct archive_entry *, const char *);
 246 __LA_DECL void  archive_entry_copy_uname_w(struct archive_entry *, const wchar_t *);
 247 __LA_DECL int   archive_entry_update_uname_utf8(struct archive_entry *, const char *);
 248 /*
 249  * Routines to bulk copy fields to/from a platform-native "struct
 250  * stat."  Libarchive used to just store a struct stat inside of each
 251  * archive_entry object, but this created issues when trying to
 252  * manipulate archives on systems different than the ones they were
 253  * created on.
 254  *
 255  * TODO: On Linux, provide both stat32 and stat64 versions of these functions.
 256  */
 257 __LA_DECL const struct stat     *archive_entry_stat(struct archive_entry *);
 258 __LA_DECL void  archive_entry_copy_stat(struct archive_entry *, const struct stat *);
 259
 260 /*
 261  * ACL routines.  This used to simply store and return text-format ACL
 262  * strings, but that proved insufficient for a number of reasons:
 263  *   = clients need control over uname/uid and gname/gid mappings
 264  *   = there are many different ACL text formats
 265  *   = would like to be able to read/convert archives containing ACLs
 266  *     on platforms that lack ACL libraries
 267  *
 268  *  This last point, in particular, forces me to implement a reasonably
 269  *  complete set of ACL support routines.
 270  *
 271  *  TODO: Extend this to support NFSv4/NTFS permissions.  That should
 272  *  allow full ACL support on Mac OS, in particular, which uses
 273  *  POSIX.1e-style interfaces to manipulate NFSv4/NTFS permissions.
 274  */
 275
 276 /*
 277  * Permission bits mimic POSIX.1e.  Note that I've not followed POSIX.1e's
 278  * "permset"/"perm" abstract type nonsense.  A permset is just a simple
 279  * bitmap, following long-standing Unix tradition.
 280  */
 281 #define ARCHIVE_ENTRY_ACL_EXECUTE       1
 282 #define ARCHIVE_ENTRY_ACL_WRITE         2
 283 #define ARCHIVE_ENTRY_ACL_READ          4
 284
 285 /* We need to be able to specify either or both of these. */
 286 #define ARCHIVE_ENTRY_ACL_TYPE_ACCESS   256
 287 #define ARCHIVE_ENTRY_ACL_TYPE_DEFAULT  512
 288
 289 /* Tag values mimic POSIX.1e */
 290 #define ARCHIVE_ENTRY_ACL_USER          10001   /* Specified user. */
 291 #define ARCHIVE_ENTRY_ACL_USER_OBJ      10002   /* User who owns the file. */
 292 #define ARCHIVE_ENTRY_ACL_GROUP         10003   /* Specified group. */
 293 #define ARCHIVE_ENTRY_ACL_GROUP_OBJ     10004   /* Group who owns the file. */
 294 #define ARCHIVE_ENTRY_ACL_MASK          10005   /* Modify group access. */
 295 #define ARCHIVE_ENTRY_ACL_OTHER         10006   /* Public. */
 296
 297 /*
 298  * Set the ACL by clearing it and adding entries one at a time.
 299  * Unlike the POSIX.1e ACL routines, you must specify the type
 300  * (access/default) for each entry.  Internally, the ACL data is just
 301  * a soup of entries.  API calls here allow you to retrieve just the
 302  * entries of interest.  This design (which goes against the spirit of
 303  * POSIX.1e) is useful for handling archive formats that combine
 304  * default and access information in a single ACL list.
 305  */
 306 __LA_DECL void   archive_entry_acl_clear(struct archive_entry *);
 307 __LA_DECL void   archive_entry_acl_add_entry(struct archive_entry *,
 308             int /* type */, int /* permset */, int /* tag */,
 309             int /* qual */, const char * /* name */);
 310 __LA_DECL void   archive_entry_acl_add_entry_w(struct archive_entry *,
 311             int /* type */, int /* permset */, int /* tag */,
 312             int /* qual */, const wchar_t * /* name */);
 313
 314 /*
 315  * To retrieve the ACL, first "reset", then repeatedly ask for the
 316  * "next" entry.  The want_type parameter allows you to request only
 317  * access entries or only default entries.
 318  */
 319 __LA_DECL int    archive_entry_acl_reset(struct archive_entry *, int /* want_type */);
 320 __LA_DECL int    archive_entry_acl_next(struct archive_entry *, int /* want_type */,
 321             int * /* type */, int * /* permset */, int * /* tag */,
 322             int * /* qual */, const char ** /* name */);
 323 __LA_DECL int    archive_entry_acl_next_w(struct archive_entry *, int /* want_type */,
 324             int * /* type */, int * /* permset */, int * /* tag */,
 325             int * /* qual */, const wchar_t ** /* name */);
 326
 327 /*
 328  * Construct a text-format ACL.  The flags argument is a bitmask that
 329  * can include any of the following:
 330  *
 331  * ARCHIVE_ENTRY_ACL_TYPE_ACCESS - Include access entries.
 332  * ARCHIVE_ENTRY_ACL_TYPE_DEFAULT - Include default entries.
 333  * ARCHIVE_ENTRY_ACL_STYLE_EXTRA_ID - Include extra numeric ID field in
 334  *    each ACL entry.  (As used by 'star'.)
 335  * ARCHIVE_ENTRY_ACL_STYLE_MARK_DEFAULT - Include "default:" before each
 336  *    default ACL entry.
 337  */
 338 #define ARCHIVE_ENTRY_ACL_STYLE_EXTRA_ID        1024
 339 #define ARCHIVE_ENTRY_ACL_STYLE_MARK_DEFAULT    2048
 340 __LA_DECL const wchar_t *archive_entry_acl_text_w(struct archive_entry *,
 341                     int /* flags */);
 342
 343 /* Return a count of entries matching 'want_type' */
 344 __LA_DECL int    archive_entry_acl_count(struct archive_entry *, int /* want_type */);
 345
 346 /*
 347  * Private ACL parser.  This is private because it handles some
 348  * very weird formats that clients should not be messing with.
 349  * Clients should only deal with their platform-native formats.
 350  * Because of the need to support many formats cleanly, new arguments
 351  * are likely to get added on a regular basis.  Clients who try to use
 352  * this interface are likely to be surprised when it changes.
 353  *
 354  * You were warned!
 355  *
 356  * TODO: Move this declaration out of the public header and into
 357  * a private header.  Warnings above are silly.
 358  */
 359 __LA_DECL int            __archive_entry_acl_parse_w(struct archive_entry *,
 360                     const wchar_t *, int /* type */);
 361
 362 /*
 363  * extended attributes
 364  */
 365
 366 __LA_DECL void   archive_entry_xattr_clear(struct archive_entry *);
 367 __LA_DECL void   archive_entry_xattr_add_entry(struct archive_entry *,
 368             const char * /* name */, const void * /* value */,
 369             size_t /* size */);
 370
 371 /*
 372  * To retrieve the xattr list, first "reset", then repeatedly ask for the
 373  * "next" entry.
 374  */
 375
 376 __LA_DECL int   archive_entry_xattr_count(struct archive_entry *);
 377 __LA_DECL int   archive_entry_xattr_reset(struct archive_entry *);
 378 __LA_DECL int   archive_entry_xattr_next(struct archive_entry *,
 379             const char ** /* name */, const void ** /* value */, size_t *);
 380
 381 /*
 382  * Utility to match up hardlinks.
 383  *
 384  * The 'struct archive_entry_linkresolver' is a cache of archive entries
 385  * for files with multiple links.  Here's how to use it:
 386  *   1. Create a lookup object with archive_entry_linkresolver_new()
 387  *   2. Tell it the archive format you're using.
 388  *   3. Hand each archive_entry to archive_entry_linkify().
 389  *      That function will return 0, 1, or 2 entries that should
 390  *      be written.
 391  *   4. Call archive_entry_linkify(resolver, NULL) until
 392  *      no more entries are returned.
 393  *   5. Call archive_entry_link_resolver_free(resolver) to free resources.
 394  *
 395  * The entries returned have their hardlink and size fields updated
 396  * appropriately.  If an entry is passed in that does not refer to
 397  * a file with multiple links, it is returned unchanged.  The intention
 398  * is that you should be able to simply filter all entries through
 399  * this machine.
 400  *
 401  * To make things more efficient, be sure that each entry has a valid
 402  * nlinks value.  The hardlink cache uses this to track when all links
 403  * have been found.  If the nlinks value is zero, it will keep every
 404  * name in the cache indefinitely, which can use a lot of memory.
 405  *
 406  * Note that archive_entry_size() is reset to zero if the file
 407  * body should not be written to the archive.  Pay attention!
 408  */
 409 __LA_DECL struct archive_entry_linkresolver;
 410
 411 /*
 412  * There are three different strategies for marking hardlinks.
 413  * The descriptions below name them after the best-known
 414  * formats that rely on each strategy:
 415  *
 416  * "Old cpio" is the simplest, it always returns any entry unmodified.
 417  *    As far as I know, only cpio formats use this.  Old cpio archives
 418  *    store every link with the full body; the onus is on the dearchiver
 419  *    to detect and properly link the files as they are restored.
 420  * "tar" is also pretty simple; it caches a copy the first time it sees
 421  *    any link.  Subsequent appearances are modified to be hardlink
 422  *    references to the first one without any body.  Used by all tar
 423  *    formats, although the newest tar formats permit the "old cpio" strategy
 424  *    as well.  This strategy is very simple for the dearchiver,
 425  *    and reasonably straightforward for the archiver.
 426  * "new cpio" is trickier.  It stores the body only with the last
 427  *    occurrence.  The complication is that we might not
 428  *    see every link to a particular file in a single session, so
 429  *    there's no easy way to know when we've seen the last occurrence.
 430  *    The solution here is to queue one link until we see the next.
 431  *    At the end of the session, you can enumerate any remaining
 432  *    entries by calling archive_entry_linkify(NULL) and store those
 433  *    bodies.  If you have a file with three links l1, l2, and l3,
 434  *    you'll get the following behavior if you see all three links:
 435  *           linkify(l1) => NULL   (the resolver stores l1 internally)
 436  *           linkify(l2) => l1     (resolver stores l2, you write l1)
 437  *           linkify(l3) => l2, l3 (all links seen, you can write both).
 438  *    If you only see l1 and l2, you'll get this behavior:
 439  *           linkify(l1) => NULL
 440  *           linkify(l2) => l1
 441  *           linkify(NULL) => l2   (at end, you retrieve remaining links)
 442  *    As the name suggests, this strategy is used by newer cpio variants.
 443  *    It's noticably more complex for the archiver, slightly more complex
 444  *    for the dearchiver than the tar strategy, but makes it straightforward
 445  *    to restore a file using any link by simply continuing to scan until
 446  *    you see a link that is stored with a body.  In contrast, the tar
 447  *    strategy requires you to rescan the archive from the beginning to
 448  *    correctly extract an arbitrary link.
 449  */
 450
 451 __LA_DECL struct archive_entry_linkresolver *archive_entry_linkresolver_new(void);
 452 __LA_DECL void archive_entry_linkresolver_set_strategy(
 453         struct archive_entry_linkresolver *, int /* format_code */);
 454 __LA_DECL void archive_entry_linkresolver_free(struct archive_entry_linkresolver *);
 455 __LA_DECL void archive_entry_linkify(struct archive_entry_linkresolver *,
 456     struct archive_entry **, struct archive_entry **);
 457
 458 #ifdef __cplusplus
 459 }
 460 #endif
 461
 462 /* This is meaningless outside of this header. */
 463 #undef __LA_DECL
 464
 465 #endif /* !ARCHIVE_ENTRY_H_INCLUDED */