usr/src/old/cpio/cpioformat.5

.\" Copyright 1991 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" %sccs.include.redist.roff%
.\"
.\"     @(#)cpioformat.5        5.3 (Berkeley) %G%
.\"
.Dd
.Dt CPIO 5
.Os
.Sh NAME
.Nm cpio
.Nd format of cpio archive
.Sh DESCRIPTION
The header structure, when the
.Fl c
option of
.Xr cpio 1
is not used, is:
.Bd -literal -offset indent
struct {
        short   h_magic,
                h_dev;
        ushort  h_ino,
                h_mode,
                h_uid,
                h_gid;
        short   h_nlink,
                h_rdev,
                h_mtime[2],
                h_namesize,
                h_filesize[2];
        char    h_name[h_namesize rounded to word];
} Hdr;
.Ed
.Pp
When the
.Fl c
option is used, the header information is described by:
.Bd -literal -offset indent
sscanf(Chdr,"%6o%6o%6o%6o%6o%6o%6o%6o%11lo%6o%11lo%s",
&Hdr.h_magic, &Hdr.h_dev, &Hdr.h_ino, &Hdr.h_mode,
&Hdr.h_uid, &Hdr.h_gid, &Hdr.h_nlink, &Hdr.h_rdev,
&Longtime, &Hdr.h_namesize,&Longfile,Hdr.h_name);
.Ed
.Pp
.Fa Longtime
and
.Fa Longfile
are equivalent to
.Fa Hdr.h_mtime
and
.Fa Hdr.h_filesize ,
respectively.
The contents of each file are
recorded in an element of the array of varying lenght
structures, archive, together with other items describing
the file.
Every instance of
.Fa h_magic
contains the constant
070707 (octal).
The itimes
.Fa h_dev
through
.Fa h_mtime
have
meanings explained in
.Xr stat 2 .
The length of the null-terminated path name
.Fa H_name ,
icluding the null byte, is
given by
.Fa h_namesize .
.Pp
The last record of the archive always contains the name
TRAILER!!!.  Special files, directories, and the trailer are
recorded with
.Fa H_filesize
equal to zero.
.Sh SEE ALSO
.Xr cpio 1 ,
.Xr find 1 ,
.Xr stat 2
.Sh HISTORY
A
.Xr cpio 1
command appeared in
.At V .
This file format is derived from the
.At V
sources which were contributed to the public domain by AT&T.