Tribblix: manual page: libarchive

LIBARCHIVE_CHANGES(3) Introduction to Library Functions

NAME

libarchive_changes - 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 Unicode as the native
wchar_t encoding, which is true on Windows, modern 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 UTF-8 and libarchive 2 incorrectly assumed that wchar_t
strings can be easily converted to 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, archive_entry objects can now
be bound to a particular archive when they are created. The automatic
character set conversions performed by archive_entry objects when
reading and writing filenames, usernames, and other strings will now
use an appropriate default character set:

If the 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 int64_t instead of less-portable types such
as off_t, gid_t, uid_t, and ino_t.

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

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

+o 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:

+o archive_entry_gid(), archive_entry_set_gid()
+o archive_entry_uid(), archive_entry_set_uid()
+o archive_entry_ino(), archive_entry_set_ino()
+o archive_read_data_block(), archive_write_data_block()
+o archive_read_disk_gname(), archive_read_disk_uname()
+o archive_read_disk_set_gname_lookup(),
archive_read_disk_set_group_lookup(),
archive_read_disk_set_uname_lookup(),
archive_read_disk_set_user_lookup()
+o archive_skip_callback()
+o archive_read_extract_set_skip_file(),
archive_write_disk_set_skip_file(), archive_write_set_skip_file()
+o archive_write_disk_set_group_lookup(),
archive_write_disk_set_user_lookup()

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

NAME

Multiple Filters

Character Set Handling

Prototype Changes

Deprecated Symbols

Removed Symbols

SEE ALSO