diff options
Diffstat (limited to 'kernel/fs/squashfs/decompressor.c')
| -rw-r--r-- | kernel/fs/squashfs/decompressor.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/kernel/fs/squashfs/decompressor.c b/kernel/fs/squashfs/decompressor.c new file mode 100644 index 000000000..e9034bf6e --- /dev/null +++ b/kernel/fs/squashfs/decompressor.c @@ -0,0 +1,148 @@ +/* + * 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/buffer_head.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 + +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_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 *buffer = NULL, *comp_opts; + struct squashfs_page_actor *actor = NULL; + int length = 0; + + /* + * Read decompressor specific options from file system if present + */ + if (SQUASHFS_COMP_OPTS(flags)) { + buffer = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL); + if (buffer == NULL) { + comp_opts = ERR_PTR(-ENOMEM); + goto out; + } + + actor = squashfs_page_actor_init(&buffer, 1, 0); + if (actor == NULL) { + comp_opts = ERR_PTR(-ENOMEM); + goto out; + } + + length = squashfs_read_data(sb, + sizeof(struct squashfs_super_block), 0, NULL, actor); + + if (length < 0) { + comp_opts = ERR_PTR(length); + goto out; + } + } + + comp_opts = squashfs_comp_opts(msblk, buffer, length); + +out: + kfree(actor); + kfree(buffer); + 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; +} |