/*
* This function is called by mksquashfs to dump the parsed
* compressor options in a format suitable for writing to the
* compressor options field in the filesystem (stored immediately
* after the superblock).
*
* This function returns a pointer to the compression options structure
* to be stored (and the size), or NULL if there are no compression
* options
*
*/
static void *gzip_dump_options(int block_size, int *size)
{
static struct gzip_comp_opts comp_opts;
int i, strategies = 0;
/*
* If default compression options of:
* compression-level: 8 and
* window-size: 15 and
* strategy_count == 0 then
* don't store a compression options structure (this is compatible
* with the legacy implementation of GZIP for Squashfs)
*/
if(compression_level == GZIP_DEFAULT_COMPRESSION_LEVEL &&
window_size == GZIP_DEFAULT_WINDOW_SIZE &&
strategy_count == 0)
return NULL;
for(i = 0; strategy[i].name; i++)
strategies |= strategy[i].selected << i;
comp_opts.compression_level = compression_level;
comp_opts.window_size = window_size;
comp_opts.strategy = strategies;
SQUASHFS_INSWAP_COMP_OPTS(&comp_opts);
*size = sizeof(comp_opts);
return &comp_opts;
}
static void zstd_display_options(void *buffer, int size)
{
struct zstd_comp_opts *comp_opts = buffer;
/* we expect a comp_opts structure of sufficient size to be present */
if (size < sizeof(*comp_opts))
goto failed;
SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
if (comp_opts->compression_level < 1 ||
comp_opts->compression_level > ZSTD_maxCLevel()) {
fprintf(stderr, "zstd: bad compression level in compression "
"options structure\n");
goto failed;
}
printf("\tcompression-level %d\n", comp_opts->compression_level);
return;
failed:
fprintf(stderr, "zstd: error reading stored compressor options from "
"filesystem!\n");
}
/*
* This function is a helper specifically for the append mode of
* mksquashfs. Its purpose is to set the internal compressor state
* to the stored compressor options in the passed compressor options
* structure.
*
* In effect this function sets up the compressor options
* to the same state they were when the filesystem was originally
* generated, this is to ensure on appending, the compressor uses
* the same compression options that were used to generate the
* original filesystem.
*
* Note, even if there are no compressor options, this function is still
* called with an empty compressor structure (size == 0), to explicitly
* set the default options, this is to ensure any user supplied
* -X options on the appending mksquashfs command line are over-ridden.
*
* This function returns 0 on sucessful extraction of options, and -1 on error.
*/
static int zstd_extract_options(int block_size, void *buffer, int size)
{
struct zstd_comp_opts *comp_opts = buffer;
if (size == 0) {
/* Set default values */
compression_level = ZSTD_DEFAULT_COMPRESSION_LEVEL;
return 0;
}
/* we expect a comp_opts structure of sufficient size to be present */
if (size < sizeof(*comp_opts))
goto failed;
SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
if (comp_opts->compression_level < 1 ||
comp_opts->compression_level > ZSTD_maxCLevel()) {
fprintf(stderr, "zstd: bad compression level in compression "
"options structure\n");
goto failed;
}
compression_level = comp_opts->compression_level;
return 0;
failed:
fprintf(stderr, "zstd: error reading stored compressor options from "
"filesystem!\n");
return -1;
}
void lz4_display_options(void *buffer, int size)
{
struct lz4_comp_opts *comp_opts = buffer;
/* check passed comp opts struct is of the correct length */
if(size < sizeof(*comp_opts))
goto failed;
SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
/* we expect the stream format to be LZ4_LEGACY */
if(comp_opts->version != LZ4_LEGACY) {
fprintf(stderr, "lz4: unknown LZ4 version\n");
goto failed;
}
/*
* Check compression flags, currently only LZ4_HC ("high compression")
* can be set.
*/
if(comp_opts->flags & ~LZ4_FLAGS_MASK) {
fprintf(stderr, "lz4: unknown LZ4 flags\n");
goto failed;
}
if(comp_opts->flags & LZ4_HC)
printf("\tHigh Compression option specified (-Xhc)\n");
return;
failed:
fprintf(stderr, "lz4: error reading stored compressor options from "
"filesystem!\n");
}
/*
* This function is a helper specifically for the append mode of
* mksquashfs. Its purpose is to set the internal compressor state
* to the stored compressor options in the passed compressor options
* structure.
*
* In effect this function sets up the compressor options
* to the same state they were when the filesystem was originally
* generated, this is to ensure on appending, the compressor uses
* the same compression options that were used to generate the
* original filesystem.
*
* Note, even if there are no compressor options, this function is still
* called with an empty compressor structure (size == 0), to explicitly
* set the default options, this is to ensure any user supplied
* -X options on the appending mksquashfs command line are over-ridden
*
* This function returns 0 on sucessful extraction of options, and
* -1 on error
*/
static int lz4_extract_options(int block_size, void *buffer, int size)
{
struct lz4_comp_opts *comp_opts = buffer;
/* we expect a comp_opts structure to be present */
if(size < sizeof(*comp_opts))
goto failed;
SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
/* we expect the stream format to be LZ4_LEGACY */
if(comp_opts->version != LZ4_LEGACY) {
fprintf(stderr, "lz4: unknown LZ4 version\n");
goto failed;
}
/*
* Check compression flags, currently only LZ4_HC ("high compression")
* can be set.
*/
if(comp_opts->flags == LZ4_HC)
hc = 1;
else if(comp_opts->flags != 0) {
fprintf(stderr, "lz4: unknown LZ4 flags\n");
goto failed;
}
return 0;
failed:
fprintf(stderr, "lz4: error reading stored compressor options from "
"filesystem!\n");
return -1;
}
/*
* This function is called by mksquashfs to dump the parsed
* compressor options in a format suitable for writing to the
* compressor options field in the filesystem (stored immediately
* after the superblock).
*
* This function returns a pointer to the compression options structure
* to be stored (and the size), or NULL if there are no compression
* options
*
* Currently LZ4 always returns a comp_opts structure, with
* the version indicating LZ4_LEGACY stream fomat. This is to
* easily accomodate changes in the kernel code to different
* stream formats
*/
static void *lz4_dump_options(int block_size, int *size)
{
static struct lz4_comp_opts comp_opts;
comp_opts.version = LZ4_LEGACY;
comp_opts.flags = hc ? LZ4_HC : 0;
SQUASHFS_INSWAP_COMP_OPTS(&comp_opts);
*size = sizeof(comp_opts);
return &comp_opts;
}
/*
* This function is called by mksquashfs to dump the parsed
* compressor options in a format suitable for writing to the
* compressor options field in the filesystem (stored immediately
* after the superblock).
*
* This function returns a pointer to the compression options structure
* to be stored (and the size), or NULL if there are no compression
* options.
*/
static void *zstd_dump_options(int block_size, int *size)
{
static struct zstd_comp_opts comp_opts;
/* don't return anything if the options are all default */
if (compression_level == ZSTD_DEFAULT_COMPRESSION_LEVEL)
return NULL;
comp_opts.compression_level = compression_level;
SQUASHFS_INSWAP_COMP_OPTS(&comp_opts);
*size = sizeof(comp_opts);
return &comp_opts;
}
/*
* This function is a helper specifically for the append mode of
* mksquashfs. Its purpose is to set the internal compressor state
* to the stored compressor options in the passed compressor options
* structure.
*
* In effect this function sets up the compressor options
* to the same state they were when the filesystem was originally
* generated, this is to ensure on appending, the compressor uses
* the same compression options that were used to generate the
* original filesystem.
*
* Note, even if there are no compressor options, this function is still
* called with an empty compressor structure (size == 0), to explicitly
* set the default options, this is to ensure any user supplied
* -X options on the appending mksquashfs command line are over-ridden
*
* This function returns 0 on sucessful extraction of options, and
* -1 on error
*/
static int gzip_extract_options(int block_size, void *buffer, int size)
{
struct gzip_comp_opts *comp_opts = buffer;
int i;
if(size == 0) {
/* Set default values */
compression_level = GZIP_DEFAULT_COMPRESSION_LEVEL;
window_size = GZIP_DEFAULT_WINDOW_SIZE;
strategy_count = 0;
return 0;
}
/* we expect a comp_opts structure of sufficient size to be present */
if(size < sizeof(*comp_opts))
goto failed;
SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
/* Check comp_opts structure for correctness */
if(comp_opts->compression_level < 1 ||
comp_opts->compression_level > 9) {
fprintf(stderr, "gzip: bad compression level in "
"compression options structure\n");
goto failed;
}
compression_level = comp_opts->compression_level;
if(comp_opts->window_size < 8 ||
comp_opts->window_size > 15) {
fprintf(stderr, "gzip: bad window size in "
"compression options structure\n");
goto failed;
}
window_size = comp_opts->window_size;
strategy_count = 0;
for(i = 0; strategy[i].name; i++) {
if((comp_opts->strategy >> i) & 1) {
strategy[i].selected = 1;
strategy_count ++;
} else
strategy[i].selected = 0;
}
/*
* This function is a helper specifically for unsquashfs.
* Its purpose is to check that the compression options are
* understood by this version of LZ4.
*
* This is important for LZ4 because the format understood by the
* Linux kernel may change from the already obsolete legacy format
* currently supported.
*
* If this does happen, then this version of LZ4 will not be able to decode
* the newer format. So we need to check for this.
*
* This function returns 0 on sucessful checking of options, and
* -1 on error
*/
static int lz4_check_options(int block_size, void *buffer, int size)
{
struct lz4_comp_opts *comp_opts = buffer;
/* we expect a comp_opts structure to be present */
if(size < sizeof(*comp_opts))
goto failed;
SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
/* we expect the stream format to be LZ4_LEGACY */
if(comp_opts->version != LZ4_LEGACY) {
fprintf(stderr, "lz4: unknown LZ4 version\n");
goto failed;
}
return 0;
failed:
fprintf(stderr, "lz4: error reading stored compressor options from "
"filesystem!\n");
return -1;
}