diff options
Diffstat (limited to 'Utilities/cmlibarchive/libarchive/libarchive.3')
-rw-r--r-- | Utilities/cmlibarchive/libarchive/libarchive.3 | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/Utilities/cmlibarchive/libarchive/libarchive.3 b/Utilities/cmlibarchive/libarchive/libarchive.3 new file mode 100644 index 0000000..8c19d00 --- /dev/null +++ b/Utilities/cmlibarchive/libarchive/libarchive.3 @@ -0,0 +1,331 @@ +.\" Copyright (c) 2003-2007 Tim Kientzle +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD: src/lib/libarchive/libarchive.3,v 1.11 2007/01/09 08:05:56 kientzle Exp $ +.\" +.Dd August 19, 2006 +.Dt LIBARCHIVE 3 +.Os +.Sh NAME +.Nm libarchive +.Nd functions for reading and writing streaming archives +.Sh LIBRARY +.Lb libarchive +.Sh OVERVIEW +The +.Nm +library provides a flexible interface for reading and writing +streaming archive files such as tar and cpio. +The library is inherently stream-oriented; readers serially iterate through +the archive, writers serially add things to the archive. +In particular, note that there is no built-in support for +random access nor for in-place modification. +.Pp +When reading an archive, the library automatically detects the +format and the compression. +The library currently has read support for: +.Bl -bullet -compact +.It +old-style tar archives, +.It +most variants of the POSIX +.Dq ustar +format, +.It +the POSIX +.Dq pax interchange +format, +.It +GNU-format tar archives, +.It +most common cpio archive formats, +.It +ISO9660 CD images (with or without RockRidge extensions), +.It +Zip archives. +.El +The library automatically detects archives compressed with +.Xr gzip 1 , +.Xr bzip2 1 , +or +.Xr compress 1 +and decompresses them transparently. +.Pp +When writing an archive, you can specify the compression +to be used and the format to use. +The library can write +.Bl -bullet -compact +.It +POSIX-standard +.Dq ustar +archives, +.It +POSIX +.Dq pax interchange format +archives, +.It +POSIX octet-oriented cpio archives, +.It +two different variants of shar archives. +.El +Pax interchange format is an extension of the tar archive format that +eliminates essentially all of the limitations of historic tar formats +in a standard fashion that is supported +by POSIX-compliant +.Xr pax 1 +implementations on many systems as well as several newer implementations of +.Xr tar 1 . +Note that the default write format will suppress the pax extended +attributes for most entries; explicitly requesting pax format will +enable those attributes for all entries. +.Pp +The read and write APIs are accessed through the +.Fn archive_read_XXX +functions and the +.Fn archive_write_XXX +functions, respectively, and either can be used independently +of the other. +.Pp +The rest of this manual page provides an overview of the library +operation. +More detailed information can be found in the individual manual +pages for each API or utility function. +.Sh READING AN ARCHIVE +To read an archive, you must first obtain an initialized +.Tn struct archive +object from +.Fn archive_read_new . +You can then modify this object for the desired operations with the +various +.Fn archive_read_set_XXX +and +.Fn archive_read_support_XXX +functions. +In particular, you will need to invoke appropriate +.Fn archive_read_support_XXX +functions to enable the corresponding compression and format +support. +Note that these latter functions perform two distinct operations: +they cause the corresponding support code to be linked into your +program, and they enable the corresponding auto-detect code. +Unless you have specific constraints, you will generally want +to invoke +.Fn archive_read_support_compression_all +and +.Fn archive_read_support_format_all +to enable auto-detect for all formats and compression types +currently supported by the library. +.Pp +Once you have prepared the +.Tn struct archive +object, you call +.Fn archive_read_open +to actually open the archive and prepare it for reading. +There are several variants of this function; +the most basic expects you to provide pointers to several +functions that can provide blocks of bytes from the archive. +There are convenience forms that allow you to +specify a filename, file descriptor, +.Ft "FILE *" +object, or a block of memory from which to read the archive data. +Note that the core library makes no assumptions about the +size of the blocks read; +callback functions are free to read whatever block size is +most appropriate for the medium. +.Pp +Each archive entry consists of a header followed by a certain +amount of data. +You can obtain the next header with +.Fn archive_read_next_header , +which returns a pointer to an +.Tn struct archive_entry +structure with information about the current archive element. +If the entry is a regular file, then the header will be followed +by the file data. +You can use +.Fn archive_read_data +(which works much like the +.Xr read 2 +system call) +to read this data from the archive. +You may prefer to use the higher-level +.Fn archive_read_data_skip , +which reads and discards the data for this entry, +.Fn archive_read_data_to_buffer , +which reads the data into an in-memory buffer, +.Fn archive_read_data_to_file , +which copies the data to the provided file descriptor, or +.Fn archive_read_extract , +which recreates the specified entry on disk and copies data +from the archive. +In particular, note that +.Fn archive_read_extract +uses the +.Tn struct archive_entry +structure that you provide it, which may differ from the +entry just read from the archive. +In particular, many applications will want to override the +pathname, file permissions, or ownership. +.Pp +Once you have finished reading data from the archive, you +should call +.Fn archive_read_close +to close the archive, then call +.Fn archive_read_finish +to release all resources, including all memory allocated by the library. +.Pp +The +.Xr archive_read 3 +manual page provides more detailed calling information for this API. +.Sh WRITING AN ARCHIVE +You use a similar process to write an archive. +The +.Fn archive_write_new +function creates an archive object useful for writing, +the various +.Fn archive_write_set_XXX +functions are used to set parameters for writing the archive, and +.Fn archive_write_open +completes the setup and opens the archive for writing. +.Pp +Individual archive entries are written in a three-step +process: +You first initialize a +.Tn struct archive_entry +structure with information about the new entry. +At a minimum, you should set the pathname of the +entry and provide a +.Va struct stat +with a valid +.Va st_mode +field, which specifies the type of object and +.Va st_size +field, which specifies the size of the data portion of the object. +The +.Fn archive_write_header +function actually writes the header data to the archive. +You can then use +.Fn archive_write_data +to write the actual data. +.Pp +After all entries have been written, use the +.Fn archive_write_finish +function to release all resources. +.Pp +The +.Xr archive_write 3 +manual page provides more detailed calling information for this API. +.Sh DESCRIPTION +Detailed descriptions of each function are provided by the +corresponding manual pages. +.Pp +All of the functions utilize an opaque +.Tn struct archive +datatype that provides access to the archive contents. +.Pp +The +.Tn struct archive_entry +structure contains a complete description of a single archive +entry. +It uses an opaque interface that is fully documented in +.Xr archive_entry 3 . +.Pp +Users familiar with historic formats should be aware that the newer +variants have eliminated most restrictions on the length of textual fields. +Clients should not assume that filenames, link names, user names, or +group names are limited in length. +In particular, pax interchange format can easily accommodate pathnames +in arbitrary character sets that exceed +.Va PATH_MAX . +.Sh RETURN VALUES +Most functions return zero on success, non-zero on error. +The return value indicates the general severity of the error, ranging +from +.Cm ARCHIVE_WARN , +which indicates a minor problem that should probably be reported +to the user, to +.Cm ARCHIVE_FATAL , +which indicates a serious problem that will prevent any further +operations on this archive. +On error, the +.Fn archive_errno +function can be used to retrieve a numeric error code (see +.Xr errno 2 ) . +The +.Fn archive_error_string +returns a textual error message suitable for display. +.Pp +.Fn archive_read_new +and +.Fn archive_write_new +return pointers to an allocated and initialized +.Tn struct archive +object. +.Pp +.Fn archive_read_data +and +.Fn archive_write_data +return a count of the number of bytes actually read or written. +A value of zero indicates the end of the data for this entry. +A negative value indicates an error, in which case the +.Fn archive_errno +and +.Fn archive_error_string +functions can be used to obtain more information. +.Sh ENVIRONMENT +There are character set conversions within the +.Xr archive_entry 3 +functions that are impacted by the currently-selected locale. +.Sh SEE ALSO +.Xr tar 1 , +.Xr archive_entry 3 , +.Xr archive_read 3 , +.Xr archive_util 3 , +.Xr archive_write 3 , +.Xr tar 5 +.Sh HISTORY +The +.Nm libarchive +library first appeared in +.Fx 5.3 . +.Sh AUTHORS +.An -nosplit +The +.Nm libarchive +library was written by +.An Tim Kientzle Aq kientzle@acm.org . +.Sh BUGS +Some archive formats support information that is not supported by +.Tn struct archive_entry . +Such information cannot be fully archived or restored using this library. +This includes, for example, comments, character sets, +or the arbitrary key/value pairs that can appear in +pax interchange format archives. +.Pp +Conversely, of course, not all of the information that can be +stored in an +.Tn struct archive_entry +is supported by all formats. +For example, cpio formats do not support nanosecond timestamps; +old tar formats do not support large device numbers. |