diff options
Diffstat (limited to 'fs/fs_internal.c')
-rw-r--r-- | fs/fs_internal.c | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/fs/fs_internal.c b/fs/fs_internal.c new file mode 100644 index 0000000..58b4410 --- /dev/null +++ b/fs/fs_internal.c @@ -0,0 +1,92 @@ +/* + * 2017 by Marek Behun <marek.behun@nic.cz> + * + * Derived from code in ext4/dev.c, which was based on reiserfs/dev.c + * + * SPDX-License-Identifier: GPL-2.0 + */ + +#include <common.h> +#include <compiler.h> +#include <part.h> +#include <memalign.h> + +int fs_devread(struct blk_desc *blk, disk_partition_t *partition, + lbaint_t sector, int byte_offset, int byte_len, char *buf) +{ + unsigned block_len; + int log2blksz = blk->log2blksz; + ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, (blk ? blk->blksz : 0)); + if (blk == NULL) { + printf("** Invalid Block Device Descriptor (NULL)\n"); + return 0; + } + + /* Check partition boundaries */ + if ((sector + ((byte_offset + byte_len - 1) >> log2blksz)) + >= partition->size) { + printf("%s read outside partition " LBAFU "\n", __func__, + sector); + return 0; + } + + /* Get the read to the beginning of a partition */ + sector += byte_offset >> log2blksz; + byte_offset &= blk->blksz - 1; + + debug(" <" LBAFU ", %d, %d>\n", sector, byte_offset, byte_len); + + if (byte_offset != 0) { + int readlen; + /* read first part which isn't aligned with start of sector */ + if (blk_dread(blk, partition->start + sector, 1, + (void *)sec_buf) != 1) { + printf(" ** %s read error **\n", __func__); + return 0; + } + readlen = min((int)blk->blksz - byte_offset, + byte_len); + memcpy(buf, sec_buf + byte_offset, readlen); + buf += readlen; + byte_len -= readlen; + sector++; + } + + if (byte_len == 0) + return 1; + + /* read sector aligned part */ + block_len = byte_len & ~(blk->blksz - 1); + + if (block_len == 0) { + ALLOC_CACHE_ALIGN_BUFFER(u8, p, blk->blksz); + + block_len = blk->blksz; + blk_dread(blk, partition->start + sector, 1, + (void *)p); + memcpy(buf, p, byte_len); + return 1; + } + + if (blk_dread(blk, partition->start + sector, + block_len >> log2blksz, (void *)buf) != + block_len >> log2blksz) { + printf(" ** %s read error - block\n", __func__); + return 0; + } + block_len = byte_len & ~(blk->blksz - 1); + buf += block_len; + byte_len -= block_len; + sector += block_len / blk->blksz; + + if (byte_len != 0) { + /* read rest of data which are not in whole sector */ + if (blk_dread(blk, partition->start + sector, 1, + (void *)sec_buf) != 1) { + printf("* %s read error - last part\n", __func__); + return 0; + } + memcpy(buf, sec_buf, byte_len); + } + return 1; +} |