// 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

   * Phillip Lougher <phillip@squashfs.org.uk>

   *

   * zlib_wrapper.c
   */
  
  
  #include <linux/mutex.h>
  #include <linux/buffer_head.h>

  #include <linux/slab.h>

  #include <linux/zlib.h>

  #include <linux/vmalloc.h>

  
  #include "squashfs_fs.h"
  #include "squashfs_fs_sb.h"

  #include "squashfs.h"

  #include "decompressor.h"

  #include "page_actor.h"

  static void *zlib_init(struct squashfs_sb_info *dummy, void *buff)

  {
  	z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
  	if (stream == NULL)
  		goto failed;

  	stream->workspace = vmalloc(zlib_inflate_workspacesize());

  	if (stream->workspace == NULL)
  		goto failed;
  
  	return stream;
  
  failed:
  	ERROR("Failed to allocate zlib workspace
  ");
  	kfree(stream);

  	return ERR_PTR(-ENOMEM);

  }

  static void zlib_free(void *strm)

  {
  	z_stream *stream = strm;
  
  	if (stream)

  		vfree(stream->workspace);

  	kfree(stream);
  }

  static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,

  	struct buffer_head **bh, int b, int offset, int length,
  	struct squashfs_page_actor *output)

  {

  	int zlib_err, zlib_init = 0, k = 0;

  	z_stream *stream = strm;

  	stream->avail_out = PAGE_SIZE;

  	stream->next_out = squashfs_first_page(output);

  	stream->avail_in = 0;

  	do {

  		if (stream->avail_in == 0 && k < b) {

  			int avail = min(length, msblk->devblksize - offset);
  			length -= avail;

  			stream->next_in = bh[k]->b_data + offset;
  			stream->avail_in = avail;

  			offset = 0;
  		}

  		if (stream->avail_out == 0) {
  			stream->next_out = squashfs_next_page(output);
  			if (stream->next_out != NULL)

  				stream->avail_out = PAGE_SIZE;

  		}
  
  		if (!zlib_init) {

  			zlib_err = zlib_inflateInit(stream);

  			if (zlib_err != Z_OK) {
  				squashfs_finish_page(output);

  				goto out;

  			}

  			zlib_init = 1;
  		}

  		zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);

  		if (stream->avail_in == 0 && k < b)

  			put_bh(bh[k++]);
  	} while (zlib_err == Z_OK);

  	squashfs_finish_page(output);

  	if (zlib_err != Z_STREAM_END)
  		goto out;

  	zlib_err = zlib_inflateEnd(stream);

  	if (zlib_err != Z_OK)
  		goto out;

  	if (k < b)
  		goto out;

  	return stream->total_out;

  out:

  	for (; k < b; k++)
  		put_bh(bh[k]);
  
  	return -EIO;
  }

  
  const struct squashfs_decompressor squashfs_zlib_comp_ops = {
  	.init = zlib_init,
  	.free = zlib_free,
  	.decompress = zlib_uncompress,
  	.id = ZLIB_COMPRESSION,
  	.name = "zlib",
  	.supported = 1
  };