// SPDX-License-Identifier: GPL-2.0
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/*
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* uncompress.c
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*
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* (C) Copyright 1999 Linus Torvalds
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*
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* cramfs interfaces to the uncompression library. There's really just
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* three entrypoints:
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*
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* - cramfs_uncompress_init() - called to initialize the thing.
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* - cramfs_uncompress_exit() - tell me when you're done
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* - cramfs_uncompress_block() - uncompress a block.
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*
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* NOTE NOTE NOTE! The uncompression is entirely single-threaded. We
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* only have one stream, and we'll initialize it only once even if it
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* then is used by multiple filesystems.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/vmalloc.h>
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#include <linux/zlib.h>
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#include "internal.h"
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static z_stream stream;
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static int initialized;
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/* Returns length of decompressed data. */
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int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen)
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{
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int err;
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stream.next_in = src;
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stream.avail_in = srclen;
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stream.next_out = dst;
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stream.avail_out = dstlen;
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err = zlib_inflateReset(&stream);
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if (err != Z_OK) {
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pr_err("zlib_inflateReset error %d\n", err);
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zlib_inflateEnd(&stream);
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zlib_inflateInit(&stream);
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}
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err = zlib_inflate(&stream, Z_FINISH);
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if (err != Z_STREAM_END)
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goto err;
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return stream.total_out;
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err:
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pr_err("Error %d while decompressing!\n", err);
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pr_err("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen);
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return -EIO;
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}
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int cramfs_uncompress_init(void)
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{
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if (!initialized++) {
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stream.workspace = vmalloc(zlib_inflate_workspacesize());
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if (!stream.workspace) {
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initialized = 0;
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return -ENOMEM;
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}
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stream.next_in = NULL;
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stream.avail_in = 0;
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zlib_inflateInit(&stream);
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}
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return 0;
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}
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void cramfs_uncompress_exit(void)
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{
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if (!--initialized) {
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zlib_inflateEnd(&stream);
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vfree(stream.workspace);
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}
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}
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