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-rw-r--r--squashfs-tools/xz_wrapper.c551
1 files changed, 551 insertions, 0 deletions
diff --git a/squashfs-tools/xz_wrapper.c b/squashfs-tools/xz_wrapper.c
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+++ b/squashfs-tools/xz_wrapper.c
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+/*
+ * Copyright (c) 2010, 2011, 2012, 2013, 2021, 2022
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * xz_wrapper.c
+ *
+ * Support for XZ (LZMA2) compression using XZ Utils liblzma
+ * http://tukaani.org/xz/
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <lzma.h>
+
+#include "squashfs_fs.h"
+#include "xz_wrapper.h"
+#include "compressor.h"
+
+static struct bcj bcj[] = {
+ { "x86", LZMA_FILTER_X86, 0 },
+ { "powerpc", LZMA_FILTER_POWERPC, 0 },
+ { "ia64", LZMA_FILTER_IA64, 0 },
+ { "arm", LZMA_FILTER_ARM, 0 },
+ { "armthumb", LZMA_FILTER_ARMTHUMB, 0 },
+ { "sparc", LZMA_FILTER_SPARC, 0 },
+ { NULL, LZMA_VLI_UNKNOWN, 0 }
+};
+
+static int filter_count = 1;
+static int dictionary_size = 0;
+static float dictionary_percent = 0;
+
+
+/*
+ * This function is called by the options parsing code in mksquashfs.c
+ * to parse any -X compressor option.
+ *
+ * Two specific options are supported:
+ * -Xbcj
+ * -Xdict-size
+ *
+ * This function returns:
+ * >=0 (number of additional args parsed) on success
+ * -1 if the option was unrecognised, or
+ * -2 if the option was recognised, but otherwise bad in
+ * some way (e.g. invalid parameter)
+ *
+ * Note: this function sets internal compressor state, but does not
+ * pass back the results of the parsing other than success/failure.
+ * The xz_dump_options() function is called later to get the options in
+ * a format suitable for writing to the filesystem.
+ */
+static int xz_options(char *argv[], int argc)
+{
+ int i;
+ char *name;
+
+ if(strcmp(argv[0], "-Xbcj") == 0) {
+ if(argc < 2) {
+ fprintf(stderr, "xz: -Xbcj missing filter\n");
+ goto failed;
+ }
+
+ name = argv[1];
+ while(name[0] != '\0') {
+ for(i = 0; bcj[i].name; i++) {
+ int n = strlen(bcj[i].name);
+ if((strncmp(name, bcj[i].name, n) == 0) &&
+ (name[n] == '\0' ||
+ name[n] == ',')) {
+ if(bcj[i].selected == 0) {
+ bcj[i].selected = 1;
+ filter_count++;
+ }
+ name += name[n] == ',' ? n + 1 : n;
+ break;
+ }
+ }
+ if(bcj[i].name == NULL) {
+ fprintf(stderr, "xz: -Xbcj unrecognised "
+ "filter\n");
+ goto failed;
+ }
+ }
+
+ return 1;
+ } else if(strcmp(argv[0], "-Xdict-size") == 0) {
+ char *b;
+ float size;
+
+ if(argc < 2) {
+ fprintf(stderr, "xz: -Xdict-size missing dict-size\n");
+ goto failed;
+ }
+
+ size = strtof(argv[1], &b);
+ if(*b == '%') {
+ if(size <= 0 || size > 100) {
+ fprintf(stderr, "xz: -Xdict-size percentage "
+ "should be 0 < dict-size <= 100\n");
+ goto failed;
+ }
+
+ dictionary_percent = size;
+ dictionary_size = 0;
+ } else {
+ if((float) ((int) size) != size) {
+ fprintf(stderr, "xz: -Xdict-size can't be "
+ "fractional unless a percentage of the"
+ " block size\n");
+ goto failed;
+ }
+
+ dictionary_percent = 0;
+ dictionary_size = (int) size;
+
+ if(*b == 'k' || *b == 'K')
+ dictionary_size *= 1024;
+ else if(*b == 'm' || *b == 'M')
+ dictionary_size *= 1024 * 1024;
+ else if(*b != '\0') {
+ fprintf(stderr, "xz: -Xdict-size invalid "
+ "dict-size\n");
+ goto failed;
+ }
+ }
+
+ return 1;
+ }
+
+ return -1;
+
+failed:
+ return -2;
+}
+
+
+/*
+ * This function is called after all options have been parsed.
+ * It is used to do post-processing on the compressor options using
+ * values that were not expected to be known at option parse time.
+ *
+ * In this case block_size may not be known until after -Xdict-size has
+ * been processed (in the case where -b is specified after -Xdict-size)
+ *
+ * This function returns 0 on successful post processing, or
+ * -1 on error
+ */
+static int xz_options_post(int block_size)
+{
+ /*
+ * if -Xdict-size has been specified use this to compute the datablock
+ * dictionary size
+ */
+ if(dictionary_size || dictionary_percent) {
+ int n;
+
+ if(dictionary_size) {
+ if(dictionary_size > block_size) {
+ fprintf(stderr, "xz: -Xdict-size is larger than"
+ " block_size\n");
+ goto failed;
+ }
+ } else
+ dictionary_size = block_size * dictionary_percent / 100;
+
+ if(dictionary_size < 8192) {
+ fprintf(stderr, "xz: -Xdict-size should be 8192 bytes "
+ "or larger\n");
+ goto failed;
+ }
+
+ /*
+ * dictionary_size must be storable in xz header as either
+ * 2^n or as 2^n+2^(n+1)
+ */
+ n = ffs(dictionary_size) - 1;
+ if(dictionary_size != (1 << n) &&
+ dictionary_size != ((1 << n) + (1 << (n + 1)))) {
+ fprintf(stderr, "xz: -Xdict-size is an unsupported "
+ "value, dict-size must be storable in xz "
+ "header\n");
+ fprintf(stderr, "as either 2^n or as 2^n+2^(n+1). "
+ "Example dict-sizes are 75%%, 50%%, 37.5%%, "
+ "25%%,\n");
+ fprintf(stderr, "or 32K, 16K, 8K etc.\n");
+ goto failed;
+ }
+
+ } else
+ /* No -Xdict-size specified, use defaults */
+ dictionary_size = block_size;
+
+ return 0;
+
+failed:
+ 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
+ */
+static void *xz_dump_options(int block_size, int *size)
+{
+ static struct comp_opts comp_opts;
+ int flags = 0, i;
+
+ /*
+ * don't store compressor specific options in file system if the
+ * default options are being used - no compressor options in the
+ * file system means the default options are always assumed
+ *
+ * Defaults are:
+ * metadata dictionary size: SQUASHFS_METADATA_SIZE
+ * datablock dictionary size: block_size
+ * 1 filter
+ */
+ if(dictionary_size == block_size && filter_count == 1)
+ return NULL;
+
+ for(i = 0; bcj[i].name; i++)
+ flags |= bcj[i].selected << i;
+
+ comp_opts.dictionary_size = dictionary_size;
+ comp_opts.flags = flags;
+
+ 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 xz_extract_options(int block_size, void *buffer, int size)
+{
+ struct comp_opts *comp_opts = buffer;
+ int flags, i, n;
+
+ if(size == 0) {
+ /* set defaults */
+ dictionary_size = block_size;
+ flags = 0;
+ } else {
+ /* check passed comp opts struct is of the correct length */
+ if(size != sizeof(struct comp_opts))
+ goto failed;
+
+ SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
+
+ dictionary_size = comp_opts->dictionary_size;
+ flags = comp_opts->flags;
+
+ /*
+ * check that the dictionary size seems correct - the dictionary
+ * size should 2^n or 2^n+2^(n+1)
+ */
+ n = ffs(dictionary_size) - 1;
+ if(dictionary_size != (1 << n) &&
+ dictionary_size != ((1 << n) + (1 << (n + 1))))
+ goto failed;
+ }
+
+ filter_count = 1;
+ for(i = 0; bcj[i].name; i++) {
+ if((flags >> i) & 1) {
+ bcj[i].selected = 1;
+ filter_count ++;
+ } else
+ bcj[i].selected = 0;
+ }
+
+ return 0;
+
+failed:
+ fprintf(stderr, "xz: error reading stored compressor options from "
+ "filesystem!\n");
+
+ return -1;
+}
+
+
+static void xz_display_options(void *buffer, int size)
+{
+ struct comp_opts *comp_opts = buffer;
+ int dictionary_size, flags, printed;
+ int i, n;
+
+ /* check passed comp opts struct is of the correct length */
+ if(size != sizeof(struct comp_opts))
+ goto failed;
+
+ SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
+
+ dictionary_size = comp_opts->dictionary_size;
+ flags = comp_opts->flags;
+
+ /*
+ * check that the dictionary size seems correct - the dictionary
+ * size should 2^n or 2^n+2^(n+1)
+ */
+ n = ffs(dictionary_size) - 1;
+ if(dictionary_size != (1 << n) &&
+ dictionary_size != ((1 << n) + (1 << (n + 1))))
+ goto failed;
+
+ printf("\tDictionary size %d\n", dictionary_size);
+
+ printed = 0;
+ for(i = 0; bcj[i].name; i++) {
+ if((flags >> i) & 1) {
+ if(printed)
+ printf(", ");
+ else
+ printf("\tFilters selected: ");
+ printf("%s", bcj[i].name);
+ printed = 1;
+ }
+ }
+
+ if(!printed)
+ printf("\tNo filters specified\n");
+ else
+ printf("\n");
+
+ return;
+
+failed:
+ fprintf(stderr, "xz: error reading stored compressor options from "
+ "filesystem!\n");
+}
+
+
+/*
+ * This function is called by mksquashfs to initialise the
+ * compressor, before compress() is called.
+ *
+ * This function returns 0 on success, and
+ * -1 on error
+ */
+static int xz_init(void **strm, int block_size, int datablock)
+{
+ int i, j, filters = datablock ? filter_count : 1;
+ struct filter *filter = malloc(filters * sizeof(struct filter));
+ struct xz_stream *stream;
+
+ if(filter == NULL)
+ goto failed;
+
+ stream = *strm = malloc(sizeof(struct xz_stream));
+ if(stream == NULL)
+ goto failed2;
+
+ stream->filter = filter;
+ stream->filters = filters;
+
+ memset(filter, 0, filters * sizeof(struct filter));
+
+ stream->dictionary_size = datablock ? dictionary_size :
+ SQUASHFS_METADATA_SIZE;
+
+ filter[0].filter[0].id = LZMA_FILTER_LZMA2;
+ filter[0].filter[0].options = &stream->opt;
+ filter[0].filter[1].id = LZMA_VLI_UNKNOWN;
+
+ for(i = 0, j = 1; datablock && bcj[i].name; i++) {
+ if(bcj[i].selected) {
+ filter[j].buffer = malloc(block_size);
+ if(filter[j].buffer == NULL)
+ goto failed3;
+ filter[j].filter[0].id = bcj[i].id;
+ filter[j].filter[1].id = LZMA_FILTER_LZMA2;
+ filter[j].filter[1].options = &stream->opt;
+ filter[j].filter[2].id = LZMA_VLI_UNKNOWN;
+ j++;
+ }
+ }
+
+ return 0;
+
+failed3:
+ for(i = 1; i < filters; i++)
+ free(filter[i].buffer);
+ free(stream);
+
+failed2:
+ free(filter);
+
+failed:
+ return -1;
+}
+
+
+static int xz_compress(void *strm, void *dest, void *src, int size,
+ int block_size, int *error)
+{
+ int i;
+ lzma_ret res = 0;
+ struct xz_stream *stream = strm;
+ struct filter *selected = NULL;
+
+ stream->filter[0].buffer = dest;
+
+ for(i = 0; i < stream->filters; i++) {
+ struct filter *filter = &stream->filter[i];
+
+ if(lzma_lzma_preset(&stream->opt, LZMA_PRESET_DEFAULT))
+ goto failed;
+
+ stream->opt.dict_size = stream->dictionary_size;
+
+ filter->length = 0;
+ res = lzma_stream_buffer_encode(filter->filter,
+ LZMA_CHECK_CRC32, NULL, src, size, filter->buffer,
+ &filter->length, block_size);
+
+ if(res == LZMA_OK) {
+ if(!selected || selected->length > filter->length)
+ selected = filter;
+ } else if(res != LZMA_BUF_ERROR)
+ goto failed;
+ }
+
+ if(!selected)
+ /*
+ * Output buffer overflow. Return out of buffer space
+ */
+ return 0;
+
+ if(selected->buffer != dest)
+ memcpy(dest, selected->buffer, selected->length);
+
+ return (int) selected->length;
+
+failed:
+ /*
+ * All other errors return failure, with the compressor
+ * specific error code in *error
+ */
+ *error = res;
+ return -1;
+}
+
+
+static int xz_uncompress(void *dest, void *src, int size, int outsize,
+ int *error)
+{
+ size_t src_pos = 0;
+ size_t dest_pos = 0;
+ uint64_t memlimit = MEMLIMIT;
+
+ lzma_ret res = lzma_stream_buffer_decode(&memlimit, 0, NULL,
+ src, &src_pos, size, dest, &dest_pos, outsize);
+
+ if(res == LZMA_OK && size == (int) src_pos)
+ return (int) dest_pos;
+ else {
+ *error = res;
+ return -1;
+ }
+}
+
+
+static void xz_usage(FILE *stream)
+{
+ fprintf(stream, "\t -Xbcj filter1,filter2,...,filterN\n");
+ fprintf(stream, "\t\tCompress using filter1,filter2,...,filterN in");
+ fprintf(stream, " turn\n\t\t(in addition to no filter), and choose");
+ fprintf(stream, " the best compression.\n");
+ fprintf(stream, "\t\tAvailable filters: x86, arm, armthumb,");
+ fprintf(stream, " powerpc, sparc, ia64\n");
+ fprintf(stream, "\t -Xdict-size <dict-size>\n");
+ fprintf(stream, "\t\tUse <dict-size> as the XZ dictionary size. The");
+ fprintf(stream, " dictionary size\n\t\tcan be specified as a");
+ fprintf(stream, " percentage of the block size, or as an\n\t\t");
+ fprintf(stream, "absolute value. The dictionary size must be less");
+ fprintf(stream, " than or equal\n\t\tto the block size and 8192 bytes");
+ fprintf(stream, " or larger. It must also be\n\t\tstorable in the xz");
+ fprintf(stream, " header as either 2^n or as 2^n+2^(n+1).\n\t\t");
+ fprintf(stream, "Example dict-sizes are 75%%, 50%%, 37.5%%, 25%%, or");
+ fprintf(stream, " 32K, 16K, 8K\n\t\tetc.\n");
+}
+
+
+static int option_args(char *option)
+{
+ if(strcmp(option, "-Xbcj") == 0 ||
+ strcmp(option, "-Xdict-size") == 0)
+ return 1;
+
+ return 0;
+}
+
+
+struct compressor xz_comp_ops = {
+ .init = xz_init,
+ .compress = xz_compress,
+ .uncompress = xz_uncompress,
+ .options = xz_options,
+ .options_post = xz_options_post,
+ .dump_options = xz_dump_options,
+ .extract_options = xz_extract_options,
+ .display_options = xz_display_options,
+ .usage = xz_usage,
+ .option_args = option_args,
+ .id = XZ_COMPRESSION,
+ .name = "xz",
+ .supported = 1
+};
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