diff options
Diffstat (limited to 'fs/squashfs/xz_wrapper.c')
| -rw-r--r-- | fs/squashfs/xz_wrapper.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/fs/squashfs/xz_wrapper.c b/fs/squashfs/xz_wrapper.c new file mode 100644 index 000000000..6c49481a2 --- /dev/null +++ b/fs/squashfs/xz_wrapper.c @@ -0,0 +1,196 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Squashfs - a compressed read only filesystem for Linux + * + * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 + * Phillip Lougher <phillip@squashfs.org.uk> + * + * xz_wrapper.c + */ + + +#include <linux/mutex.h> +#include <linux/bio.h> +#include <linux/slab.h> +#include <linux/xz.h> +#include <linux/bitops.h> + +#include "squashfs_fs.h" +#include "squashfs_fs_sb.h" +#include "squashfs.h" +#include "decompressor.h" +#include "page_actor.h" + +struct squashfs_xz { + struct xz_dec *state; + struct xz_buf buf; +}; + +struct disk_comp_opts { + __le32 dictionary_size; + __le32 flags; +}; + +struct comp_opts { + int dict_size; +}; + +static void *squashfs_xz_comp_opts(struct squashfs_sb_info *msblk, + void *buff, int len) +{ + struct disk_comp_opts *comp_opts = buff; + struct comp_opts *opts; + int err = 0, n; + + opts = kmalloc(sizeof(*opts), GFP_KERNEL); + if (opts == NULL) { + err = -ENOMEM; + goto out2; + } + + if (comp_opts) { + /* check compressor options are the expected length */ + if (len < sizeof(*comp_opts)) { + err = -EIO; + goto out; + } + + opts->dict_size = le32_to_cpu(comp_opts->dictionary_size); + + /* the dictionary size should be 2^n or 2^n+2^(n+1) */ + n = ffs(opts->dict_size) - 1; + if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) + + (1 << (n + 1))) { + err = -EIO; + goto out; + } + } else + /* use defaults */ + opts->dict_size = max_t(int, msblk->block_size, + SQUASHFS_METADATA_SIZE); + + return opts; + +out: + kfree(opts); +out2: + return ERR_PTR(err); +} + + +static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff) +{ + struct comp_opts *comp_opts = buff; + struct squashfs_xz *stream; + int err; + + stream = kmalloc(sizeof(*stream), GFP_KERNEL); + if (stream == NULL) { + err = -ENOMEM; + goto failed; + } + + stream->state = xz_dec_init(XZ_PREALLOC, comp_opts->dict_size); + if (stream->state == NULL) { + kfree(stream); + err = -ENOMEM; + goto failed; + } + + return stream; + +failed: + ERROR("Failed to initialise xz decompressor\n"); + return ERR_PTR(err); +} + + +static void squashfs_xz_free(void *strm) +{ + struct squashfs_xz *stream = strm; + + if (stream) { + xz_dec_end(stream->state); + kfree(stream); + } +} + + +static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm, + struct bio *bio, int offset, int length, + struct squashfs_page_actor *output) +{ + struct bvec_iter_all iter_all = {}; + struct bio_vec *bvec = bvec_init_iter_all(&iter_all); + int total = 0, error = 0; + struct squashfs_xz *stream = strm; + + xz_dec_reset(stream->state); + stream->buf.in_pos = 0; + stream->buf.in_size = 0; + stream->buf.out_pos = 0; + stream->buf.out_size = PAGE_SIZE; + stream->buf.out = squashfs_first_page(output); + if (IS_ERR(stream->buf.out)) { + error = PTR_ERR(stream->buf.out); + goto finish; + } + + for (;;) { + enum xz_ret xz_err; + + if (stream->buf.in_pos == stream->buf.in_size) { + const void *data; + int avail; + + if (!bio_next_segment(bio, &iter_all)) { + /* XZ_STREAM_END must be reached. */ + error = -EIO; + break; + } + + avail = min(length, ((int)bvec->bv_len) - offset); + data = bvec_virt(bvec); + length -= avail; + stream->buf.in = data + offset; + stream->buf.in_size = avail; + stream->buf.in_pos = 0; + offset = 0; + } + + if (stream->buf.out_pos == stream->buf.out_size) { + stream->buf.out = squashfs_next_page(output); + if (IS_ERR(stream->buf.out)) { + error = PTR_ERR(stream->buf.out); + break; + } else if (stream->buf.out != NULL) { + stream->buf.out_pos = 0; + total += PAGE_SIZE; + } + } + + xz_err = xz_dec_run(stream->state, &stream->buf); + if (xz_err == XZ_STREAM_END) + break; + if (xz_err != XZ_OK) { + error = -EIO; + break; + } + } + +finish: + squashfs_finish_page(output); + + return error ? error : total + stream->buf.out_pos; +} + +const struct squashfs_decompressor squashfs_xz_comp_ops = { + .init = squashfs_xz_init, + .comp_opts = squashfs_xz_comp_opts, + .free = squashfs_xz_free, + .decompress = squashfs_xz_uncompress, + .id = XZ_COMPRESSION, + .name = "xz", + .alloc_buffer = 1, + .supported = 1 +}; |