CPIO(5)

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 of varying length structures, archive, 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).