src/include/ipxe/cpio.h

#ifndef _IPXE_CPIO_H
#define _IPXE_CPIO_H

/** @file
 *
 * CPIO archives
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );

#include <stdint.h>
#include <ipxe/image.h>

/** A CPIO archive header
 *
 * All field are hexadecimal ASCII numbers padded with '0' on the
 * left to the full width of the field.
 */
struct cpio_header {
	/** The string "070701" or "070702" */
	char c_magic[6];
	/** File inode number */
	char c_ino[8];
	/** File mode and permissions */
	char c_mode[8];
	/** File uid */
	char c_uid[8];
	/** File gid */
	char c_gid[8];
	/** Number of links */
	char c_nlink[8];
	/** Modification time */
	char c_mtime[8];
	/** Size of data field */
	char c_filesize[8];
	/** Major part of file device number */
	char c_maj[8];
	/** Minor part of file device number */
	char c_min[8];
	/** Major part of device node reference */
	char c_rmaj[8];
	/** Minor part of device node reference */
	char c_rmin[8];
	/** Length of filename, including final NUL */
	char c_namesize[8];
	/** Checksum of data field if c_magic is 070702, othersize zero */
	char c_chksum[8];
} __attribute__ (( packed ));

/** CPIO magic */
#define CPIO_MAGIC "070701"

/** CPIO type for regular files */
#define CPIO_MODE_FILE 0100000

/** CPIO type for directories */
#define CPIO_MODE_DIR 0040000

/** CPIO header length alignment */
#define CPIO_ALIGN 4

/**
 * Get CPIO image name
 *
 * @v image		Image
 * @ret name		Image name (not NUL terminated)
 */
static inline __attribute__ (( always_inline )) const char *
cpio_name ( struct image *image ) {
	return image->cmdline;
}

/**
 * Get CPIO header zero-padding length
 *
 * @v len		Length of CPIO header (including name, excluding NUL)
 * @ret pad_len		Padding length
 */
static inline __attribute__ (( always_inline )) size_t
cpio_pad_len ( size_t len ) {

	/* Pad by at least one byte (for name's terminating NUL) */
	return ( CPIO_ALIGN - ( len % CPIO_ALIGN ) );
}

extern size_t cpio_header ( struct image *image, unsigned int index,
			    struct cpio_header *cpio );

#endif /* _IPXE_CPIO_H */