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fs/squashfs/decompressor.c
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81f7e3824 Initial Release, ... |
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/* * Squashfs - a compressed read only filesystem for Linux * * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 * 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. * * decompressor.c */ #include <linux/types.h> #include <linux/mutex.h> #include <linux/slab.h> #include <linux/highmem.h> #include <linux/fs.h> #include "squashfs_fs.h" #include "squashfs_fs_sb.h" #include "decompressor.h" #include "squashfs.h" #include "page_actor.h" /* * This file (and decompressor.h) implements a decompressor framework for * Squashfs, allowing multiple decompressors to be easily supported */ static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = { NULL, NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0 }; #ifndef CONFIG_SQUASHFS_LZ4 static const struct squashfs_decompressor squashfs_lz4_comp_ops = { NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 0 }; #endif #ifndef CONFIG_SQUASHFS_LZO static const struct squashfs_decompressor squashfs_lzo_comp_ops = { NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0 }; #endif #ifndef CONFIG_SQUASHFS_XZ static const struct squashfs_decompressor squashfs_xz_comp_ops = { NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0 }; #endif #ifndef CONFIG_SQUASHFS_ZLIB static const struct squashfs_decompressor squashfs_zlib_comp_ops = { NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0 }; #endif #ifndef CONFIG_SQUASHFS_ZSTD static const struct squashfs_decompressor squashfs_zstd_comp_ops = { NULL, NULL, NULL, NULL, ZSTD_COMPRESSION, "zstd", 0 }; #endif static const struct squashfs_decompressor squashfs_unknown_comp_ops = { NULL, NULL, NULL, NULL, 0, "unknown", 0 }; static const struct squashfs_decompressor *decompressor[] = { &squashfs_zlib_comp_ops, &squashfs_lz4_comp_ops, &squashfs_lzo_comp_ops, &squashfs_xz_comp_ops, &squashfs_lzma_unsupported_comp_ops, &squashfs_zstd_comp_ops, &squashfs_unknown_comp_ops }; const struct squashfs_decompressor *squashfs_lookup_decompressor(int id) { int i; for (i = 0; decompressor[i]->id; i++) if (id == decompressor[i]->id) break; return decompressor[i]; } static void *get_comp_opts(struct super_block *sb, unsigned short flags) { struct squashfs_sb_info *msblk = sb->s_fs_info; void *comp_opts, *buffer = NULL; struct page *page; struct squashfs_page_actor *actor = NULL; int length = 0; if (!SQUASHFS_COMP_OPTS(flags)) return squashfs_comp_opts(msblk, buffer, length); /* * Read decompressor specific options from file system if present */ page = alloc_page(GFP_KERNEL); if (!page) return ERR_PTR(-ENOMEM); actor = squashfs_page_actor_init(&page, 1, 0, NULL); if (actor == NULL) { comp_opts = ERR_PTR(-ENOMEM); goto actor_error; } length = squashfs_read_data(sb, sizeof(struct squashfs_super_block), 0, NULL, actor); if (length < 0) { comp_opts = ERR_PTR(length); goto read_error; } buffer = kmap_atomic(page); comp_opts = squashfs_comp_opts(msblk, buffer, length); kunmap_atomic(buffer); read_error: squashfs_page_actor_free(actor, 0); actor_error: __free_page(page); return comp_opts; } void *squashfs_decompressor_setup(struct super_block *sb, unsigned short flags) { struct squashfs_sb_info *msblk = sb->s_fs_info; void *stream, *comp_opts = get_comp_opts(sb, flags); if (IS_ERR(comp_opts)) return comp_opts; stream = squashfs_decompressor_create(msblk, comp_opts); if (IS_ERR(stream)) kfree(comp_opts); return stream; } |