cpio.h

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#ifndef _IPXE_CPIO_H
#define _IPXE_CPIO_H

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

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#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

/** Alignment for CPIO archives within an initrd */
#define INITRD_ALIGN 4096

/**
 * 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 */