gzip.c File Reference

gzip compressed images More...

#include <stdlib.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/deflate.h>
#include <ipxe/uaccess.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.

                                                                         {
        struct gzip_header header;
        struct gzip_extra_header extra;
        struct gzip_crc_header crc;
        struct gzip_footer footer;
        struct deflate_chunk in;
        unsigned int strings;
        size_t offset;
        size_t len;
        off_t nul;
        int rc;

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

        /* Extract footer */
        len = ( image->len - sizeof ( footer ) );
        copy_from_user ( &footer, image->data, len, sizeof ( footer ) );

        /* Extract fixed header */
        copy_from_user ( &header, image->data, 0, sizeof ( header ) );
        offset = sizeof ( header );
        assert ( offset <= ( image->len - sizeof ( footer ) ) );

        /* Skip extra header, if present */
        if ( header.flags & GZIP_FL_EXTRA ) {
                copy_from_user ( &extra, image->data, offset,
                                 sizeof ( extra ) );
                offset += sizeof ( extra );
                offset += le16_to_cpu ( extra.len );
                if ( offset > len ) {
                        DBGC ( image, "GZIP %p overlength extra header\n",
                               image );
                        return -EINVAL;
                }
        }
        assert ( offset <= ( image->len - sizeof ( footer ) ) );

        /* 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-- ) {
                nul = memchr_user ( image->data, offset, 0, ( len - offset ) );
                if ( nul < 0 ) {
                        DBGC ( image, "GZIP %p overlength name/comment\n",
                               image );
                        return -EINVAL;
                }
                offset = ( nul + 1 /* NUL */ );
        }
        assert ( offset <= ( image->len - sizeof ( footer ) ) );

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

        /* Initialise input chunk */
        deflate_chunk_init ( &in, userptr_add ( image->data, offset ), 0, len );

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

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

        return 0;
}

References assert(), copy_from_user(), gzip_crc_header::crc, image::data, DBGC, DEFLATE_RAW, EINVAL, extra, ena_aq_header::flags, GZIP_FL_COMMENT, GZIP_FL_EXTRA, GZIP_FL_HCRC, GZIP_FL_NAME, header, image_set_len(), in, le16_to_cpu, le32_to_cpu, len, image::len, gzip_footer::len, memchr_user(), offset, rc, strerror(), userptr_add(), 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 140 of file gzip.c.

                                              {
        struct gzip_header header;
        struct gzip_footer footer;

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

        /* Check magic header */
        copy_from_user ( &header.magic, image->data, 0,
                         sizeof ( header.magic ) );
        if ( header.magic != cpu_to_be16 ( GZIP_MAGIC ) ) {
                DBGC ( image, "GZIP %p invalid magic\n", image );
                return -ENOEXEC;
        }

        return 0;
}

References copy_from_user(), cpu_to_be16, image::data, DBGC, ENOEXEC, GZIP_MAGIC, header, and image::len.

__image_type()

struct image_type gzip_image_type __image_type

(

PROBE_NORMAL

)

gzip image type