CPIO

Section: Devices and Network Interfaces (4)
Updated: May 10, 1991
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NAME

cpio - format of cpio archive  

DESCRIPTION

The header structure, when the -c option of cpio(1) is not used, is:
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;

When the -c option is used, the header information is described by:

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);

Longtime and Longfile are equivalent to Hdr.h_mtime and Hdr.h_filesize, respectively. The contents of each file are recorded in an element of the array archive, of varying length structures, together with other items describing the file. Every instance of h_magic contains the constant 070707 (octal). The items h_dev through h_mtime have meanings explained in stat(2). The length of the null-terminated path name H_name, including the null byte, is given by h_namesize.

The last record of the archive always contains the name TRAILER!!!. Special files, directories, and the trailer are recorded with H_filesize equal to zero.  

SEE ALSO

cpio(1), find(1), stat(2)  

HISTORY

A cpio(1) command appeared in AT&T System V UNIX. This file format is derived from the AT&T System V UNIX sources contributed to the public domain by AT&T.


 

Index

NAME
DESCRIPTION
SEE ALSO
HISTORY

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