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@@ -0,0 +1,151 @@
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+/*
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+ * Squashfs - a compressed read only filesystem for Linux
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+ *
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+ * Copyright (c) 2016-present, Facebook, Inc.
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+ * All rights reserved.
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+ *
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+ * This program is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU General Public License
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+ * as published by the Free Software Foundation; either version 2,
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+ * or (at your option) any later version.
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+ *
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+ * This program is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ *
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+ * zstd_wrapper.c
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+ */
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+
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+#include <linux/mutex.h>
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+#include <linux/buffer_head.h>
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+#include <linux/slab.h>
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+#include <linux/zstd.h>
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+#include <linux/vmalloc.h>
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+
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+#include "squashfs_fs.h"
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+#include "squashfs_fs_sb.h"
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+#include "squashfs.h"
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+#include "decompressor.h"
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+#include "page_actor.h"
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+
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+struct workspace {
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+ void *mem;
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+ size_t mem_size;
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+ size_t window_size;
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+};
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+
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+static void *zstd_init(struct squashfs_sb_info *msblk, void *buff)
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+{
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+ struct workspace *wksp = kmalloc(sizeof(*wksp), GFP_KERNEL);
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+
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+ if (wksp == NULL)
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+ goto failed;
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+ wksp->window_size = max_t(size_t,
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+ msblk->block_size, SQUASHFS_METADATA_SIZE);
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+ wksp->mem_size = ZSTD_DStreamWorkspaceBound(wksp->window_size);
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+ wksp->mem = vmalloc(wksp->mem_size);
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+ if (wksp->mem == NULL)
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+ goto failed;
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+
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+ return wksp;
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+
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+failed:
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+ ERROR("Failed to allocate zstd workspace\n");
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+ kfree(wksp);
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+ return ERR_PTR(-ENOMEM);
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+}
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+
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+
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+static void zstd_free(void *strm)
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+{
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+ struct workspace *wksp = strm;
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+
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+ if (wksp)
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+ vfree(wksp->mem);
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+ kfree(wksp);
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+}
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+
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+
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+static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm,
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+ struct buffer_head **bh, int b, int offset, int length,
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+ struct squashfs_page_actor *output)
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+{
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+ struct workspace *wksp = strm;
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+ ZSTD_DStream *stream;
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+ size_t total_out = 0;
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+ size_t zstd_err;
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+ int k = 0;
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+ ZSTD_inBuffer in_buf = { NULL, 0, 0 };
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+ ZSTD_outBuffer out_buf = { NULL, 0, 0 };
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+
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+ stream = ZSTD_initDStream(wksp->window_size, wksp->mem, wksp->mem_size);
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+
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+ if (!stream) {
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+ ERROR("Failed to initialize zstd decompressor\n");
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+ goto out;
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+ }
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+
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+ out_buf.size = PAGE_SIZE;
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+ out_buf.dst = squashfs_first_page(output);
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+
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+ do {
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+ if (in_buf.pos == in_buf.size && k < b) {
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+ int avail = min(length, msblk->devblksize - offset);
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+
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+ length -= avail;
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+ in_buf.src = bh[k]->b_data + offset;
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+ in_buf.size = avail;
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+ in_buf.pos = 0;
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+ offset = 0;
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+ }
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+
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+ if (out_buf.pos == out_buf.size) {
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+ out_buf.dst = squashfs_next_page(output);
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+ if (out_buf.dst == NULL) {
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+ /* Shouldn't run out of pages
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+ * before stream is done.
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+ */
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+ squashfs_finish_page(output);
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+ goto out;
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+ }
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+ out_buf.pos = 0;
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+ out_buf.size = PAGE_SIZE;
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+ }
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+
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+ total_out -= out_buf.pos;
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+ zstd_err = ZSTD_decompressStream(stream, &out_buf, &in_buf);
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+ total_out += out_buf.pos; /* add the additional data produced */
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+
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+ if (in_buf.pos == in_buf.size && k < b)
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+ put_bh(bh[k++]);
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+ } while (zstd_err != 0 && !ZSTD_isError(zstd_err));
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+
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+ squashfs_finish_page(output);
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+
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+ if (ZSTD_isError(zstd_err)) {
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+ ERROR("zstd decompression error: %d\n",
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+ (int)ZSTD_getErrorCode(zstd_err));
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+ goto out;
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+ }
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+
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+ if (k < b)
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+ goto out;
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+
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+ return (int)total_out;
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+
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+out:
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+ for (; k < b; k++)
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+ put_bh(bh[k]);
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+
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+ return -EIO;
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+}
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+
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+const struct squashfs_decompressor squashfs_zstd_comp_ops = {
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+ .init = zstd_init,
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+ .free = zstd_free,
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+ .decompress = zstd_uncompress,
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+ .id = ZSTD_COMPRESSION,
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+ .name = "zstd",
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+ .supported = 1
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+};
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Sean Purcell