// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Squashfs - a compressed read only filesystem for Linux
 *
 * Copyright (c) 2010 LG Electronics
 * Chan Jeong <chan.jeong@lge.com>
 *
 * lzo_wrapper.c
 */

#include <linux/mutex.h>
#include <linux/bio.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/lzo.h>

#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
#include "page_actor.h"

struct squashfs_lzo {
        void    *input;
        void    *output;
};

static void *lzo_init(struct squashfs_sb_info *msblk, void *buff)
{
        int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);

        struct squashfs_lzo *stream = kzalloc_obj(*stream);
        if (stream == NULL)
                goto failed;
        stream->input = vmalloc(block_size);
        if (stream->input == NULL)
                goto failed;
        stream->output = vmalloc(block_size);
        if (stream->output == NULL)
                goto failed2;

        return stream;

failed2:
        vfree(stream->input);
failed:
        ERROR("Failed to allocate lzo workspace\n");
        kfree(stream);
        return ERR_PTR(-ENOMEM);
}


static void lzo_free(void *strm)
{
        struct squashfs_lzo *stream = strm;

        if (stream) {
                vfree(stream->input);
                vfree(stream->output);
        }
        kfree(stream);
}


static int lzo_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);
        struct squashfs_lzo *stream = strm;
        void *buff = stream->input, *data;
        int bytes = length, res;
        size_t out_len = output->length;

        while (bio_next_segment(bio, &iter_all)) {
                int avail = min(bytes, ((int)bvec->bv_len) - offset);

                data = bvec_virt(bvec);
                memcpy(buff, data + offset, avail);
                buff += avail;
                bytes -= avail;
                offset = 0;
        }

        res = lzo1x_decompress_safe(stream->input, (size_t)length,
                                        stream->output, &out_len);
        if (res != LZO_E_OK)
                goto failed;

        res = bytes = (int)out_len;
        data = squashfs_first_page(output);
        buff = stream->output;
        while (data) {
                if (bytes <= PAGE_SIZE) {
                        if (!IS_ERR(data))
                                memcpy(data, buff, bytes);
                        break;
                } else {
                        if (!IS_ERR(data))
                                memcpy(data, buff, PAGE_SIZE);
                        buff += PAGE_SIZE;
                        bytes -= PAGE_SIZE;
                        data = squashfs_next_page(output);
                }
        }
        squashfs_finish_page(output);

        return res;

failed:
        return -EIO;
}

const struct squashfs_decompressor squashfs_lzo_comp_ops = {
        .init = lzo_init,
        .free = lzo_free,
        .decompress = lzo_uncompress,
        .id = LZO_COMPRESSION,
        .name = "lzo",
        .alloc_buffer = 0,
        .supported = 1
};