LIBARCHIVE_CHANGES(3)

NAME
changes in libarchive interface

CHANGES IN LIBARCHIVE 3
This page describes user-visible changes in libarchive3, and lists public functions and other symbols changed, deprecated or removed in libarchive3, along with their replacements if any.

  Multiple Filters
Libarchive2 permitted a single (input or output) filter active on an archive. Libarchive3 extends this into a variable-length stack. Where archive_write_set_compression_XXX() would replace any existing filter, archive_write_add_filter_XXX() extends the write pipeline with another filter.

  Character Set Handling
Libarchive2 assumed that the local platform uses Tn Unicode as the native Tn wchar_t encoding, which is true on Tn Windows, modern Tn Linux, and a few other systems, but is certainly not universal. As a result, pax format archives were written incorrectly on some systems, since pax format requires Tn UTF-8 and libarchive 2 incorrectly assumed that Tn wchar_t strings can be easily converted to Tn UTF-8.

Libarchive3 uses the standard iconv library to convert between character sets and is introducing the notion of a ``default character set for the archive''. To support this, Tn archive_entry objects can now be bound to a particular archive when they are created. The automatic character set conversions performed by Tn archive_entry objects when reading and writing filenames, usernames, and other strings will now use an appropriate default character set:

If the Tn archive_entry object is bound to an archive, it will use the default character set for that archive.

The platform default character encoding (as returned by nl_langinfo(CHARSET, )) will be used if nothing else is specified.

Libarchive3 also introduces charset options to many of the archive readers and writers to control the character set that will be used for filenames written in those archives. When possible, this will be set automatically based on information in the archive itself. Combining this with the notion of a default character set for the archive should allow you to configure libarchive to read archives from other platforms and have the filenames and other information transparently converted to the character encoding suitable for your application.

  Prototype Changes
These changes break binary compatibility; libarchive3 has a new shared library version to reflect these changes. The library now uses portable wide types such as Tn int64_t instead of less-portable types such as Tn off_t, Tn gid_t, Tn uid_t, and Tn ino_t.

There are a few cases where these changes will affect your source code:

    •   In some cases, libarchive's wider types will introduce the possibility of truncation: for example, on a system with a 16-bit Tn uid_t, you risk having uid
        65536
    be truncated to uid
        0,
    which can cause serious security problems.

    •   Typedef function pointer types will be incompatible. For example, if you define custom skip callbacks, you may have to use code similar to the following if you want to support building against libarchive2 and libarchive3:
        #if ARCHIVE_VERSION_NUMBER < 3000000
        typedef off_t myoff_t;
        #else
        typedef int64_t myoff_t;
        #endif
        myoff_t
        my_skip_function(struct archive *a, void *v, myoff_t o)
        {
            ... implementation ...
        }

Affected functions:

    •   archive_entry_gid(),
        archive_entry_set_gid()

    •   archive_entry_uid(),
        archive_entry_set_uid()

    •   archive_entry_ino(),
        archive_entry_set_ino()

    •   archive_read_data_block(),
        archive_write_data_block()

    •   archive_read_disk_gname(),
        archive_read_disk_uname()

    •   archive_read_disk_set_gname_lookup(),
        archive_read_disk_set_group_lookup(),
        archive_read_disk_set_uname_lookup(),
        archive_read_disk_set_user_lookup()

    •   archive_skip_callback()

    •   archive_read_extract_set_skip_file(),
        archive_write_disk_set_skip_file(),
        archive_write_set_skip_file()

    •   archive_write_disk_set_group_lookup(),
        archive_write_disk_set_user_lookup()

Where these functions or their arguments took or returned
Tn gid_t,
Tn ino_t,
Tn off_t,
or
Tn uid_t
they now take or return
Tn int64_t
or equivalent.

  Deprecated Symbols
Symbols deprecated in libarchive3 will be removed in libarchive4. These symbols, along with their replacements if any, are listed below:

    archive_position_compressed(), archive_position_uncompressed()
        archive_filter_bytes()

    archive_compression()
        archive_filter_code()

    archive_compression_name()
        archive_filter_name()

    archive_read_finish(), archive_write_finish()
        archive_read_free(), archive_write_free()

    archive_read_open_file(), archive_write_open_file()
        archive_read_open_filename(), archive_write_open_filename()

    archive_read_support_compression_all()
        archive_read_support_filter_all()

    archive_read_support_compression_bzip2()
        archive_read_support_filter_bzip2()

    archive_read_support_compression_compress()
        archive_read_support_filter_compress()

    archive_read_support_compression_gzip()
        archive_read_support_filter_gzip()

    archive_read_support_compression_lzip()
        archive_read_support_filter_lzip()

    archive_read_support_compression_lzma()
        archive_read_support_filter_lzma()

    archive_read_support_compression_none()
        archive_read_support_filter_none()

    archive_read_support_compression_program()
        archive_read_support_filter_program()

    archive_read_support_compression_program_signature()
        archive_read_support_filter_program_signature()

    archive_read_support_compression_rpm()
        archive_read_support_filter_rpm()

    archive_read_support_compression_uu()
        archive_read_support_filter_uu()

    archive_read_support_compression_xz()
        archive_read_support_filter_xz()

    archive_write_set_compression_bzip2()
        archive_write_add_filter_bzip2()

    archive_write_set_compression_compress()
        archive_write_add_filter_compress()

    archive_write_set_compression_gzip()
        archive_write_add_filter_gzip()

    archive_write_set_compression_lzip()
        archive_write_add_filter_lzip()

    archive_write_set_compression_lzma()
        archive_write_add_filter_lzma()

    archive_write_set_compression_none()
        archive_write_add_filter_none()

    archive_write_set_compression_program()
        archive_write_add_filter_program()

    archive_write_set_compression_filter()
        archive_write_add_filter_filter()

  Removed Symbols
These symbols, listed below along with their replacements if any, were deprecated in libarchive2, and are not part of libarchive3.

    archive_api_feature()
        archive_version_number()

    archive_api_version()
        archive_version_number()

    archive_version()
        archive_version_string()

    archive_version_stamp()
        archive_version_number()

    archive_read_set_filter_options()
        archive_read_set_options() or archive_read_set_filter_option()

    archive_read_set_format_options()
        archive_read_set_options() or archive_read_set_format_option()

    archive_write_set_filter_options()
        archive_write_set_options() or archive_write_set_filter_option()

    archive_write_set_format_options()
        archive_write_set_options() or archive_write_set_format_option()

    ARCHIVE_API_FEATURE
        ARCHIVE_VERSION_NUMBER

    ARCHIVE_API_VERSION
        ARCHIVE_VERSION_NUMBER

    ARCHIVE_VERSION_STAMP
        ARCHIVE_VERSION_NUMBER

    ARCHIVE_LIBRARY_VERSION
        ARCHIVE_VERSION_STRING

    ARCHIVE_COMPRESSION_NONE
        ARCHIVE_FILTER_NONE

    ARCHIVE_COMPRESSION_GZIP
        ARCHIVE_FILTER_GZIP

    ARCHIVE_COMPRESSION_BZIP2
        ARCHIVE_FILTER_BZIP2

    ARCHIVE_COMPRESSION_COMPRESS
        ARCHIVE_FILTER_COMPRESS

    ARCHIVE_COMPRESSION_PROGRAM
        ARCHIVE_FILTER_PROGRAM

    ARCHIVE_COMPRESSION_LZMA
        ARCHIVE_FILTER_LZMA

    ARCHIVE_COMPRESSION_XZ
        ARCHIVE_FILTER_XZ

    ARCHIVE_COMPRESSION_UU
        ARCHIVE_FILTER_UU

    ARCHIVE_COMPRESSION_RPM
        ARCHIVE_FILTER_RPM

    ARCHIVE_COMPRESSION_LZIP
        ARCHIVE_FILTER_LZIP

    ARCHIVE_BYTES_PER_RECORD
        512

    ARCHIVE_DEFAULT_BYTES_PER_BLOCK
        10240

SEE ALSO
libarchive(3), archive_read(3), archive_read_filter(3), archive_read_format(3), archive_read_set_options(3), archive_write(3), archive_write_filter(3), archive_write_format(3), archive_write_set_options(3), archive_util(3)