Headers archives.h(3HEAD) NAME archives.h, archives - device header DESCRIPTION /* Magic numbers */ #define CMN_ASC 0x070701 /* Cpio Magic Number for -c header */ #define CMN_BIN 070707 /* Cpio Magic Number for Binary header */ #define CMN_BBS 0143561 /* Cpio Magic Number for Byte-Swap header */ #define CMN_CRC 0x070702 /* Cpio Magic Number for CRC header */ #define CMS_ASC "070701" /* Cpio Magic String for -c header */ #define CMS_CHR "070707" /* Cpio Magic String for odc header */ #define CMS_CRC "070702" /* Cpio Magic String for CRC header */ #define CMS_LEN 6 /* Cpio Magic String length */ /* Various header and field lengths */ #define CHRSZ 76 /* -H odc size minus filename field */ #define ASCSZ 110 /* -c and CRC hdr size minus filename field */ #define TARSZ 512 /* TAR hdr size */ #define HNAMLEN 256 /* maximum filename length for binary and odc headers */ #define EXPNLEN 1024 /* maximum filename length for -c and CRC headers */ #define HTIMLEN 2 /* length of modification time field */ #define HSIZLEN 2 /* length of file size field */ /* cpio binary header definition */ struct hdr_cpio { short h_magic, /* magic number field */ h_dev; /* file system of file */ ushort_t h_ino, /* inode of file */ h_mode, /* modes of file */ h_uid, /* uid of file */ h_gid; /* gid of file */ short h_nlink, /* number of links to file */ h_rdev, /* maj/min numbers for special files */ h_mtime[HTIMLEN], /* modification time of file */ h_namesize, /* length of filename */ h_filesize[HSIZLEN]; /* size of file */ char h_name[HNAMLEN]; /* filename */ } ; /* cpio -H odc header format */ struct c_hdr { char c_magic[CMS_LEN], c_dev[6], c_ino[6], c_mode[6], c_uid[6], c_gid[6], c_nlink[6], c_rdev[6], c_mtime[11], c_namesz[6], c_filesz[11], c_name[HNAMLEN]; } ; /* -c and CRC header format */ struct Exp_cpio_hdr { char E_magic[CMS_LEN], E_ino[8], E_mode[8], E_uid[8], E_gid[8], E_nlink[8], E_mtime[8], E_filesize[8], E_maj[8], E_min[8], E_rmaj[8], E_rmin[8], E_namesize[8], E_chksum[8], E_name[EXPNLEN]; } ; /* Tar header structure and format */ #define TBLOCK 512 /* length of tar header and data blocks */ #define TNAMLEN 100 /* maximum length for tar file names */ #define TMODLEN 8 /* length of mode field */ #define TUIDLEN 8 /* length of uid field */ #define TGIDLEN 8 /* length of gid field */ #define TSIZLEN 12 /* length of size field */ #define TTIMLEN 12 /* length of modification time field */ #define TCRCLEN 8 /* length of header checksum field */ /* tar header definition */ union tblock { char dummy[TBLOCK]; struct header { char t_name[TNAMLEN]; /* name of file */ char t_mode[TMODLEN]; /* mode of file */ char t_uid[TUIDLEN]; /* uid of file */ char t_gid[TGIDLEN]; /* gid of file */ char t_size[TSIZLEN]; /* size of file in bytes */ char t_mtime[TTIMLEN]; /* modification time of file */ char t_chksum[TCRCLEN]; /* checksum of header */ char t_typeflag; /* flag to indicate type of file */ char t_linkname[TNAMLEN]; /* file this file is linked with */ char t_magic[6]; /* magic string always "ustar" */ char t_version[2]; /* version strings always "00" */ char t_uname[32]; /* owner of file in ASCII */ char t_gname[32]; /* group of file in ASCII */ char t_devmajor[8]; /* major number for special files */ char t_devminor[8]; /* minor number for special files */ char t_prefix[155]; /* pathname prefix */ } tbuf; } /* volcopy tape label format and structure */ #define VMAGLEN 8 #define VVOLLEN 6 #define VFILLEN 464 struct volcopy_label { char v_magic[VMAGLEN], v_volume[VVOLLEN], v_reels, v_reel; long v_time, v_length, v_dens, v_reelblks, /* u370 added field */ v_blksize, /* u370 added field */ v_nblocks; /* u370 added field */ char v_fill[VFILLEN]; long v_offset; /* used with -e and -reel options */ int v_type; /* does tape have nblocks field? */ } ; + + /* + * Define archive formats for extended attributes. + * + * Extended attributes are stored in two pieces. + * 1. An attribute header which has information about + * what file the attribute is for and what the attribute + * is named. + * 2. The attribute record itself. Stored as a normal file type + * of entry. + * Both the header and attribute record have special modes/typeflags + * associated with them. + * + * The names of the header in the archive look like: + * /dev/null/attr.hdr + * + * The name of the attribute looks like: + * /dev/null/attr. + * + * This is done so that an archiver that doesn't understand these formats + * can just dispose of the attribute records unless the user chooses to + * rename them via cpio -r or pax -i + * + * The format is composed of a fixed size header followed + * by a variable sized xattr_buf. If the attribute is a hard link + * to another attribute, then another xattr_buf section is included + * for the link. + * + * The xattr_buf is used to define the necessary "pathing" steps + * to get to the extended attribute. This is necessary to support + * a fully recursive attribute model where an attribute may itself + * have an attribute. + * + * The basic layout looks like this. + * + * -------------------------------- + * | | + * | xattr_hdr | + * | | + * -------------------------------- + * -------------------------------- + * | | + * | xattr_buf | + * | | + * -------------------------------- + * -------------------------------- + * | | + * | (optional link info) | + * | | + * -------------------------------- + * -------------------------------- + * | | + * | attribute itself | + * | stored as normal tar | + * | or cpio data with | + * | special mode or | + * | typeflag | + * | | + * -------------------------------- + * + */ + #define XATTR_ARCH_VERS "1.0" + + /* + * extended attribute fixed header + * + * h_version format version. + * h_size size of header + variable sized data sections. + * h_component_len Length of entire pathing section. + * h_link_component_len Length of link component section. Again same definition * as h_component_len. + */ + struct xattr_hdr { + char h_version[7]; + char h_size[10]; + char h_component_len[10]; /* total length of path component */ + char h_link_component_len[10]; + }; + + /* + * The name is encoded like this: + * filepathNULattrpathNUL[attrpathNULL]... + */ + struct xattr_buf { + char h_namesz[7]; /* length of h_names */ + char h_typeflag; /* actual typeflag of file being archived */ + char h_names[1]; /* filepathNULattrpathNUL... */ + }; + + /* + * Special values for tar archives + */ + + /* + * typeflag for tar archives. + */ + + /* + * Attribute hdr and attribute files have the following typeflag + */ + #define _XATTR_HDRTYPE 'E' + + /* + * For cpio archives the header and attribute have + * _XATTR_CPIO_MODE ORED into the mode field in both + * character and binary versions of the archive format + */ + #define _XATTR_CPIO_MODE 0xB000 + + #ifdef __cplusplus + } + #endif + + #endif /* _ARCHIVES_H */