24f48416df
It is unwise to first dereference a variable and then to check if it was NULL. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Reviewed-by: Marek Behun <marek.behun@nic.cz> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
94 lines
2.3 KiB
C
94 lines
2.3 KiB
C
/*
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* 2017 by Marek Behun <marek.behun@nic.cz>
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*
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* Derived from code in ext4/dev.c, which was based on reiserfs/dev.c
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*
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* SPDX-License-Identifier: GPL-2.0
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*/
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#include <common.h>
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#include <compiler.h>
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#include <part.h>
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#include <memalign.h>
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int fs_devread(struct blk_desc *blk, disk_partition_t *partition,
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lbaint_t sector, int byte_offset, int byte_len, char *buf)
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{
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unsigned block_len;
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int log2blksz;
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ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, (blk ? blk->blksz : 0));
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if (blk == NULL) {
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printf("** Invalid Block Device Descriptor (NULL)\n");
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return 0;
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}
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log2blksz = blk->log2blksz;
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/* Check partition boundaries */
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if ((sector + ((byte_offset + byte_len - 1) >> log2blksz))
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>= partition->size) {
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printf("%s read outside partition " LBAFU "\n", __func__,
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sector);
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return 0;
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}
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/* Get the read to the beginning of a partition */
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sector += byte_offset >> log2blksz;
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byte_offset &= blk->blksz - 1;
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debug(" <" LBAFU ", %d, %d>\n", sector, byte_offset, byte_len);
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if (byte_offset != 0) {
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int readlen;
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/* read first part which isn't aligned with start of sector */
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if (blk_dread(blk, partition->start + sector, 1,
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(void *)sec_buf) != 1) {
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printf(" ** %s read error **\n", __func__);
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return 0;
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}
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readlen = min((int)blk->blksz - byte_offset,
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byte_len);
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memcpy(buf, sec_buf + byte_offset, readlen);
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buf += readlen;
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byte_len -= readlen;
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sector++;
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}
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if (byte_len == 0)
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return 1;
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/* read sector aligned part */
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block_len = byte_len & ~(blk->blksz - 1);
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if (block_len == 0) {
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ALLOC_CACHE_ALIGN_BUFFER(u8, p, blk->blksz);
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block_len = blk->blksz;
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blk_dread(blk, partition->start + sector, 1,
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(void *)p);
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memcpy(buf, p, byte_len);
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return 1;
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}
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if (blk_dread(blk, partition->start + sector,
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block_len >> log2blksz, (void *)buf) !=
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block_len >> log2blksz) {
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printf(" ** %s read error - block\n", __func__);
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return 0;
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}
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block_len = byte_len & ~(blk->blksz - 1);
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buf += block_len;
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byte_len -= block_len;
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sector += block_len / blk->blksz;
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if (byte_len != 0) {
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/* read rest of data which are not in whole sector */
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if (blk_dread(blk, partition->start + sector, 1,
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(void *)sec_buf) != 1) {
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printf("* %s read error - last part\n", __func__);
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return 0;
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}
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memcpy(buf, sec_buf, byte_len);
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}
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return 1;
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}
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