@(#)cpioformat.5 5.2 (Berkeley) 03/29/88

C 7 cpio - format of cpio archive 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 lenght structures, archive, together with other items describing the file. Every instance of h_magic contains the constant 070707 (octal). The itimes h_dev through h_mtime have meanings explained in stat(2). The length of the null- terminated path name H_name, icluding 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. cpio(1), find(1), stat(2)