138 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Squashfs - a compressed read only filesystem for Linux4 *5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 20096 * Phillip Lougher <phillip@squashfs.org.uk>7 *8 * zlib_wrapper.c9 */10 11 12#include <linux/mutex.h>13#include <linux/bio.h>14#include <linux/slab.h>15#include <linux/zlib.h>16#include <linux/vmalloc.h>17 18#include "squashfs_fs.h"19#include "squashfs_fs_sb.h"20#include "squashfs.h"21#include "decompressor.h"22#include "page_actor.h"23 24static void *zlib_init(struct squashfs_sb_info *dummy, void *buff)25{26 z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);27 if (stream == NULL)28 goto failed;29 stream->workspace = vmalloc(zlib_inflate_workspacesize());30 if (stream->workspace == NULL)31 goto failed;32 33 return stream;34 35failed:36 ERROR("Failed to allocate zlib workspace\n");37 kfree(stream);38 return ERR_PTR(-ENOMEM);39}40 41 42static void zlib_free(void *strm)43{44 z_stream *stream = strm;45 46 if (stream)47 vfree(stream->workspace);48 kfree(stream);49}50 51 52static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,53 struct bio *bio, int offset, int length,54 struct squashfs_page_actor *output)55{56 struct bvec_iter_all iter_all = {};57 struct bio_vec *bvec = bvec_init_iter_all(&iter_all);58 int zlib_init = 0, error = 0;59 z_stream *stream = strm;60 61 stream->avail_out = PAGE_SIZE;62 stream->next_out = squashfs_first_page(output);63 stream->avail_in = 0;64 65 if (IS_ERR(stream->next_out)) {66 error = PTR_ERR(stream->next_out);67 goto finish;68 }69 70 for (;;) {71 int zlib_err;72 73 if (stream->avail_in == 0) {74 const void *data;75 int avail;76 77 if (!bio_next_segment(bio, &iter_all)) {78 /* Z_STREAM_END must be reached. */79 error = -EIO;80 break;81 }82 83 avail = min(length, ((int)bvec->bv_len) - offset);84 data = bvec_virt(bvec);85 length -= avail;86 stream->next_in = data + offset;87 stream->avail_in = avail;88 offset = 0;89 }90 91 if (stream->avail_out == 0) {92 stream->next_out = squashfs_next_page(output);93 if (IS_ERR(stream->next_out)) {94 error = PTR_ERR(stream->next_out);95 break;96 } else if (stream->next_out != NULL)97 stream->avail_out = PAGE_SIZE;98 }99 100 if (!zlib_init) {101 zlib_err = zlib_inflateInit(stream);102 if (zlib_err != Z_OK) {103 error = -EIO;104 break;105 }106 zlib_init = 1;107 }108 109 zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);110 if (zlib_err == Z_STREAM_END)111 break;112 if (zlib_err != Z_OK) {113 error = -EIO;114 break;115 }116 }117 118finish:119 squashfs_finish_page(output);120 121 if (!error)122 if (zlib_inflateEnd(stream) != Z_OK)123 error = -EIO;124 125 return error ? error : stream->total_out;126}127 128const struct squashfs_decompressor squashfs_zlib_comp_ops = {129 .init = zlib_init,130 .free = zlib_free,131 .decompress = zlib_uncompress,132 .id = ZLIB_COMPRESSION,133 .name = "zlib",134 .alloc_buffer = 1,135 .supported = 1136};137 138