gzip.c File Reference

gzip compressed images More...

#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/deflate.h>
#include <ipxe/image.h>
#include <ipxe/zlib.h>
#include <ipxe/gzip.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
static int	gzip_extract (struct image *image, struct image *extracted)
	Extract gzip image. More...
static int	gzip_probe (struct image *image)
	Probe gzip image. More...
struct image_type gzip_image_type	__image_type (PROBE_NORMAL)
	gzip image type More...

Detailed Description

gzip compressed images

Definition in file gzip.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

gzip_extract()

static int gzip_extract ( struct image *  image, struct image *  extracted  )

static

Extract gzip image.

Parameters

image	Image
extracted	Extracted image

Return values

rc	Return status code

Definition at line 48 of file gzip.c.

                                                                         {
        const struct gzip_header *header;
        const struct gzip_extra_header *extra;
        const struct gzip_crc_header *crc;
        const struct gzip_footer *footer;
        const void *data;
        size_t extra_len;
        size_t string_len;
        size_t len;
        unsigned int strings;
        int rc;

        /* Sanity check */
        assert ( image->len >= ( sizeof ( *header ) + sizeof ( *footer ) ) );
        data = image->data;
        len = image->len;

        /* Extract footer */
        assert ( len >= sizeof ( *footer ) );
        len -= sizeof ( *footer );
        footer = ( data + len );

        /* Extract fixed header */
        assert ( len >= sizeof ( *header ) );
        header = data;
        data += sizeof ( *header );
        len -= sizeof ( *header );

        /* Skip extra header, if present */
        if ( header->flags & GZIP_FL_EXTRA ) {
                if ( len < sizeof ( *extra ) ) {
                        DBGC ( image, "GZIP %s overlength extra header\n",
                               image->name );
                        return -EINVAL;
                }
                extra = data;
                data += sizeof ( *extra );
                len -= sizeof ( *extra );
                extra_len = le16_to_cpu ( extra->len );
                if ( len < extra_len ) {
                        DBGC ( image, "GZIP %s overlength extra header\n",
                               image->name );
                        return -EINVAL;
                }
                data += extra_len;
                len -= extra_len;
        }

        /* Skip name and/or comment, if present */
        strings = 0;
        if ( header->flags & GZIP_FL_NAME )
                strings++;
        if ( header->flags & GZIP_FL_COMMENT )
                strings++;
        while ( strings-- ) {
                string_len = strnlen ( data, len );
                if ( string_len == len ) {
                        DBGC ( image, "GZIP %s overlength name/comment\n",
                               image->name );
                        return -EINVAL;
                }
                data += ( string_len + 1 /* NUL */ );
                len -= ( string_len + 1 /* NUL */ );
        }

        /* Skip CRC, if present */
        if ( header->flags & GZIP_FL_HCRC ) {
                if ( len < sizeof ( *crc ) ) {
                        DBGC ( image, "GZIP %s overlength CRC header\n",
                               image->name );
                        return -EINVAL;
                }
                data += sizeof ( *crc );
                len -= sizeof ( *crc );
        }

        /* Presize extracted image */
        if ( ( rc = image_set_len ( extracted,
                                    le32_to_cpu ( footer->len ) ) ) != 0 ) {
                DBGC ( image, "GZIP %s could not presize: %s\n",
                       image->name, strerror ( rc ) );
                return rc;
        }

        /* Decompress image (expanding if necessary) */
        if ( ( rc = zlib_deflate ( DEFLATE_RAW, data, len,
                                   extracted ) ) != 0 ) {
                DBGC ( image, "GZIP %s could not decompress: %s\n",
                       image->name, strerror ( rc ) );
                return rc;
        }

        return 0;
}

References assert(), gzip_crc_header::crc, gzip_footer::crc, data, image::data, DBGC, DEFLATE_RAW, EINVAL, extra, GZIP_FL_COMMENT, GZIP_FL_EXTRA, GZIP_FL_HCRC, GZIP_FL_NAME, header, image_set_len(), le16_to_cpu, le32_to_cpu, image::len, gzip_footer::len, len, image::name, rc, strerror(), strnlen(), and zlib_deflate().

gzip_probe()

static int gzip_probe ( struct image *  image )

static

Probe gzip image.

Parameters

image

gzip image

Return values

rc	Return status code

Definition at line 149 of file gzip.c.

                                              {
        const struct gzip_header *header;
        const struct gzip_footer *footer;

        /* Sanity check */
        if ( image->len < ( sizeof ( *header ) + sizeof ( *footer ) ) ) {
                DBGC ( image, "GZIP %s image too short\n", image->name );
                return -ENOEXEC;
        }
        header = image->data;

        /* Check magic header */
        if ( header->magic != cpu_to_be16 ( GZIP_MAGIC ) ) {
                DBGC ( image, "GZIP %s invalid magic\n", image->name );
                return -ENOEXEC;
        }

        return 0;
}

References cpu_to_be16, image::data, DBGC, ENOEXEC, GZIP_MAGIC, header, image::len, and image::name.

__image_type()

struct image_type gzip_image_type __image_type

(

PROBE_NORMAL

)

gzip image type