fs/fs_internal.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * 2017 by Marek Behun <marek.behun@nic.cz>
   4  *
   5  * Derived from code in ext4/dev.c, which was based on reiserfs/dev.c
   6  */
   7
   8 #include <common.h>
   9 #include <blk.h>
  10 #include <compiler.h>
  11 #include <log.h>
  12 #include <part.h>
  13 #include <memalign.h>
  14
  15 int fs_devread(struct blk_desc *blk, struct disk_partition *partition,
  16                lbaint_t sector, int byte_offset, int byte_len, char *buf)
  17 {
  18         unsigned block_len;
  19         int log2blksz;
  20         ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, (blk ? blk->blksz : 0));
  21         if (blk == NULL) {
  22                 printf("** Invalid Block Device Descriptor (NULL)\n");
  23                 return 0;
  24         }
  25         log2blksz = blk->log2blksz;
  26
  27         /* Check partition boundaries */
  28         if ((sector + ((byte_offset + byte_len - 1) >> log2blksz))
  29             >= partition->size) {
  30                 printf("%s read outside partition " LBAFU "\n", __func__,
  31                        sector);
  32                 return 0;
  33         }
  34
  35         /* Get the read to the beginning of a partition */
  36         sector += byte_offset >> log2blksz;
  37         byte_offset &= blk->blksz - 1;
  38
  39         debug(" <" LBAFU ", %d, %d>\n", sector, byte_offset, byte_len);
  40
  41         if (byte_offset != 0) {
  42                 int readlen;
  43                 /* read first part which isn't aligned with start of sector */
  44                 if (blk_dread(blk, partition->start + sector, 1,
  45                               (void *)sec_buf) != 1) {
  46                         printf(" ** %s read error **\n", __func__);
  47                         return 0;
  48                 }
  49                 readlen = min((int)blk->blksz - byte_offset,
  50                               byte_len);
  51                 memcpy(buf, sec_buf + byte_offset, readlen);
  52                 buf += readlen;
  53                 byte_len -= readlen;
  54                 sector++;
  55         }
  56
  57         if (byte_len == 0)
  58                 return 1;
  59
  60         /* read sector aligned part */
  61         block_len = byte_len & ~(blk->blksz - 1);
  62
  63         if (block_len == 0) {
  64                 ALLOC_CACHE_ALIGN_BUFFER(u8, p, blk->blksz);
  65
  66                 block_len = blk->blksz;
  67                 blk_dread(blk, partition->start + sector, 1,
  68                           (void *)p);
  69                 memcpy(buf, p, byte_len);
  70                 return 1;
  71         }
  72
  73         if (blk_dread(blk, partition->start + sector,
  74                       block_len >> log2blksz, (void *)buf) !=
  75                         block_len >> log2blksz) {
  76                 printf(" ** %s read error - block\n", __func__);
  77                 return 0;
  78         }
  79         block_len = byte_len & ~(blk->blksz - 1);
  80         buf += block_len;
  81         byte_len -= block_len;
  82         sector += block_len / blk->blksz;
  83
  84         if (byte_len != 0) {
  85                 /* read rest of data which are not in whole sector */
  86                 if (blk_dread(blk, partition->start + sector, 1,
  87                               (void *)sec_buf) != 1) {
  88                         printf("* %s read error - last part\n", __func__);
  89                         return 0;
  90                 }
  91                 memcpy(buf, sec_buf, byte_len);
  92         }
  93         return 1;
  94 }