diff options
Diffstat (limited to 'lib/libarchive/cpio.5')
| -rw-r--r-- | lib/libarchive/cpio.5 | 325 |
1 files changed, 0 insertions, 325 deletions
diff --git a/lib/libarchive/cpio.5 b/lib/libarchive/cpio.5 deleted file mode 100644 index 5bc60fe..0000000 --- a/lib/libarchive/cpio.5 +++ /dev/null @@ -1,325 +0,0 @@ -.\" Copyright (c) 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. -.\" -.\" $FreeBSD$ -.\" -.Dd October 5, 2007 -.Dt CPIO 5 -.Os -.Sh NAME -.Nm cpio -.Nd format of cpio archive files -.Sh DESCRIPTION -The -.Nm -archive format collects any number of files, directories, and other -file system objects (symbolic links, device nodes, etc.) into a single -stream of bytes. -.Ss General Format -Each file system object in a -.Nm -archive comprises a header record with basic numeric metadata -followed by the full pathname of the entry and the file data. -The header record stores a series of integer values that generally -follow the fields in -.Va struct stat . -(See -.Xr stat 2 -for details.) -The variants differ primarily in how they store those integers -(binary, octal, or hexadecimal). -The header is followed by the pathname of the -entry (the length of the pathname is stored in the header) -and any file data. -The end of the archive is indicated by a special record with -the pathname -.Dq TRAILER!!! . -.Ss PWB format -XXX Any documentation of the original PWB/UNIX 1.0 format? XXX -.Ss Old Binary Format -The old binary -.Nm -format stores numbers as 2-byte and 4-byte binary values. -Each entry begins with a header in the following format: -.Bd -literal -offset indent -struct header_old_cpio { - unsigned short c_magic; - unsigned short c_dev; - unsigned short c_ino; - unsigned short c_mode; - unsigned short c_uid; - unsigned short c_gid; - unsigned short c_nlink; - unsigned short c_rdev; - unsigned short c_mtime[2]; - unsigned short c_namesize; - unsigned short c_filesize[2]; -}; -.Ed -.Pp -The -.Va unsigned short -fields here are 16-bit integer values; the -.Va unsigned int -fields are 32-bit integer values. -The fields are as follows -.Bl -tag -width indent -.It Va magic -The integer value octal 070707. -This value can be used to determine whether this archive is -written with little-endian or big-endian integers. -.It Va dev , Va ino -The device and inode numbers from the disk. -These are used by programs that read -.Nm -archives to determine when two entries refer to the same file. -Programs that synthesize -.Nm -archives should be careful to set these to distinct values for each entry. -.It Va mode -The mode specifies both the regular permissions and the file type. -It consists of several bit fields as follows: -.Bl -tag -width "MMMMMMM" -compact -.It 0170000 -This masks the file type bits. -.It 0140000 -File type value for sockets. -.It 0120000 -File type value for symbolic links. -For symbolic links, the link body is stored as file data. -.It 0100000 -File type value for regular files. -.It 0060000 -File type value for block special devices. -.It 0040000 -File type value for directories. -.It 0020000 -File type value for character special devices. -.It 0010000 -File type value for named pipes or FIFOs. -.It 0004000 -SUID bit. -.It 0002000 -SGID bit. -.It 0001000 -Sticky bit. -On some systems, this modifies the behavior of executables and/or directories. -.It 0000777 -The lower 9 bits specify read/write/execute permissions -for world, group, and user following standard POSIX conventions. -.El -.It Va uid , Va gid -The numeric user id and group id of the owner. -.It Va nlink -The number of links to this file. -Directories always have a value of at least two here. -Note that hardlinked files include file data with every copy in the archive. -.It Va rdev -For block special and character special entries, -this field contains the associated device number. -For all other entry types, it should be set to zero by writers -and ignored by readers. -.It Va mtime -Modification time of the file, indicated as the number -of seconds since the start of the epoch, -00:00:00 UTC January 1, 1970. -The four-byte integer is stored with the most-significant 16 bits first -followed by the least-significant 16 bits. -Each of the two 16 bit values are stored in machine-native byte order. -.It Va namesize -The number of bytes in the pathname that follows the header. -This count includes the trailing NUL byte. -.It Va filesize -The size of the file. -Note that this archive format is limited to -four gigabyte file sizes. -See -.Va mtime -above for a description of the storage of four-byte integers. -.El -.Pp -The pathname immediately follows the fixed header. -If the -.Cm namesize -is odd, an additional NUL byte is added after the pathname. -The file data is then appended, padded with NUL -bytes to an even length. -.Pp -Hardlinked files are not given special treatment; -the full file contents are included with each copy of the -file. -.Ss Portable ASCII Format -.St -susv2 -standardized an ASCII variant that is portable across all -platforms. -It is commonly known as the -.Dq old character -format or as the -.Dq odc -format. -It stores the same numeric fields as the old binary format, but -represents them as 6-character or 11-character octal values. -.Bd -literal -offset indent -struct cpio_odc_header { - char c_magic[6]; - char c_dev[6]; - char c_ino[6]; - char c_mode[6]; - char c_uid[6]; - char c_gid[6]; - char c_nlink[6]; - char c_rdev[6]; - char c_mtime[11]; - char c_namesize[6]; - char c_filesize[11]; -}; -.Ed -.Pp -The fields are identical to those in the old binary format. -The name and file body follow the fixed header. -Unlike the old binary format, there is no additional padding -after the pathname or file contents. -If the files being archived are themselves entirely ASCII, then -the resulting archive will be entirely ASCII, except for the -NUL byte that terminates the name field. -.Ss New ASCII Format -The "new" ASCII format uses 8-byte hexadecimal fields for -all numbers and separates device numbers into separate fields -for major and minor numbers. -.Bd -literal -offset indent -struct cpio_newc_header { - char c_magic[6]; - char c_ino[8]; - char c_mode[8]; - char c_uid[8]; - char c_gid[8]; - char c_nlink[8]; - char c_mtime[8]; - char c_filesize[8]; - char c_devmajor[8]; - char c_devminor[8]; - char c_rdevmajor[8]; - char c_rdevminor[8]; - char c_namesize[8]; - char c_check[8]; -}; -.Ed -.Pp -Except as specified below, the fields here match those specified -for the old binary format above. -.Bl -tag -width indent -.It Va magic -The string -.Dq 070701 . -.It Va check -This field is always set to zero by writers and ignored by readers. -See the next section for more details. -.El -.Pp -The pathname is followed by NUL bytes so that the total size -of the fixed header plus pathname is a multiple of four. -Likewise, the file data is padded to a multiple of four bytes. -Note that this format supports only 4 gigabyte files (unlike the -older ASCII format, which supports 8 gigabyte files). -.Pp -In this format, hardlinked files are handled by setting the -filesize to zero for each entry except the last one that -appears in the archive. -.Ss New CRC Format -The CRC format is identical to the new ASCII format described -in the previous section except that the magic field is set -to -.Dq 070702 -and the -.Va check -field is set to the sum of all bytes in the file data. -This sum is computed treating all bytes as unsigned values -and using unsigned arithmetic. -Only the least-significant 32 bits of the sum are stored. -.Ss HP variants -The -.Nm cpio -implementation distributed with HPUX used XXXX but stored -device numbers differently XXX. -.Ss Other Extensions and Variants -Sun Solaris uses additional file types to store extended file -data, including ACLs and extended attributes, as special -entries in cpio archives. -.Pp -XXX Others? XXX -.Sh SEE ALSO -.Xr cpio 1 , -.Xr tar 5 -.Sh STANDARDS -The -.Nm cpio -utility is no longer a part of POSIX or the Single Unix Standard. -It last appeared in -.St -susv2 . -It has been supplanted in subsequent standards by -.Xr pax 1 . -The portable ASCII format is currently part of the specification for the -.Xr pax 1 -utility. -.Sh HISTORY -The original cpio utility was written by Dick Haight -while working in AT&T's Unix Support Group. -It appeared in 1977 as part of PWB/UNIX 1.0, the -.Dq Programmer's Work Bench -derived from -.At v6 -that was used internally at AT&T. -Both the old binary and old character formats were in use -by 1980, according to the System III source released -by SCO under their -.Dq Ancient Unix -license. -The character format was adopted as part of -.St -p1003.1-88 . -XXX when did "newc" appear? Who invented it? When did HP come out with their variant? When did Sun introduce ACLs and extended attributes? XXX -.Sh BUGS -The -.Dq CRC -format is mis-named, as it uses a simple checksum and -not a cyclic redundancy check. -.Pp -The old binary format is limited to 16 bits for user id, -group id, device, and inode numbers. -It is limited to 4 gigabyte file sizes. -.Pp -The old ASCII format is limited to 18 bits for -the user id, group id, device, and inode numbers. -It is limited to 8 gigabyte file sizes. -.Pp -The new ASCII format is limited to 4 gigabyte file sizes. -.Pp -None of the cpio formats store user or group names, -which are essential when moving files between systems with -dissimilar user or group numbering. -.Pp -Especially when writing older cpio variants, it may be necessary -to map actual device/inode values to synthesized values that -fit the available fields. -With very large filesystems, this may be necessary even for -the newer formats. |
