fs/fs_internal.c

   1 /*
   2  * 2017 by Marek Behun <marek.behun@nic.cz>
   3  *
   4  * Derived from code in ext4/dev.c, which was based on reiserfs/dev.c
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0
   7  */
   8
   9 #include <common.h>
  10 #include <compiler.h>
  11 #include <part.h>
  12 #include <memalign.h>
  13
  14 int fs_devread(struct blk_desc *blk, disk_partition_t *partition,
  15                lbaint_t sector, int byte_offset, int byte_len, char *buf)
  16 {
  17         unsigned block_len;
  18         int log2blksz = blk->log2blksz;
  19         ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, (blk ? blk->blksz : 0));
  20         if (blk == NULL) {
  21                 printf("** Invalid Block Device Descriptor (NULL)\n");
  22                 return 0;
  23         }
  24
  25         /* Check partition boundaries */
  26         if ((sector + ((byte_offset + byte_len - 1) >> log2blksz))
  27             >= partition->size) {
  28                 printf("%s read outside partition " LBAFU "\n", __func__,
  29                        sector);
  30                 return 0;
  31         }
  32
  33         /* Get the read to the beginning of a partition */
  34         sector += byte_offset >> log2blksz;
  35         byte_offset &= blk->blksz - 1;
  36
  37         debug(" <" LBAFU ", %d, %d>\n", sector, byte_offset, byte_len);
  38
  39         if (byte_offset != 0) {
  40                 int readlen;
  41                 /* read first part which isn't aligned with start of sector */
  42                 if (blk_dread(blk, partition->start + sector, 1,
  43                               (void *)sec_buf) != 1) {
  44                         printf(" ** %s read error **\n", __func__);
  45                         return 0;
  46                 }
  47                 readlen = min((int)blk->blksz - byte_offset,
  48                               byte_len);
  49                 memcpy(buf, sec_buf + byte_offset, readlen);
  50                 buf += readlen;
  51                 byte_len -= readlen;
  52                 sector++;
  53         }
  54
  55         if (byte_len == 0)
  56                 return 1;
  57
  58         /* read sector aligned part */
  59         block_len = byte_len & ~(blk->blksz - 1);
  60
  61         if (block_len == 0) {
  62                 ALLOC_CACHE_ALIGN_BUFFER(u8, p, blk->blksz);
  63
  64                 block_len = blk->blksz;
  65                 blk_dread(blk, partition->start + sector, 1,
  66                           (void *)p);
  67                 memcpy(buf, p, byte_len);
  68                 return 1;
  69         }
  70
  71         if (blk_dread(blk, partition->start + sector,
  72                       block_len >> log2blksz, (void *)buf) !=
  73                         block_len >> log2blksz) {
  74                 printf(" ** %s read error - block\n", __func__);
  75                 return 0;
  76         }
  77         block_len = byte_len & ~(blk->blksz - 1);
  78         buf += block_len;
  79         byte_len -= block_len;
  80         sector += block_len / blk->blksz;
  81
  82         if (byte_len != 0) {
  83                 /* read rest of data which are not in whole sector */
  84                 if (blk_dread(blk, partition->start + sector, 1,
  85                               (void *)sec_buf) != 1) {
  86                         printf("* %s read error - last part\n", __func__);
  87                         return 0;
  88                 }
  89                 memcpy(buf, sec_buf, byte_len);
  90         }
  91         return 1;
  92 }