fs_internal.c 2.4 KB

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  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. #define LOG_CATEGORY LOGC_CORE
  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. int fs_devread(struct blk_desc *blk, struct disk_partition *partition,
  15. lbaint_t sector, int byte_offset, int byte_len, char *buf)
  16. {
  17. unsigned block_len;
  18. int log2blksz;
  19. ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, (blk ? blk->blksz : 0));
  20. if (blk == NULL) {
  21. log_err("** Invalid Block Device Descriptor (NULL)\n");
  22. return 0;
  23. }
  24. log2blksz = blk->log2blksz;
  25. /* Check partition boundaries */
  26. if ((sector + ((byte_offset + byte_len - 1) >> log2blksz))
  27. >= partition->size) {
  28. log_err("%s read outside partition " LBAFU "\n", __func__,
  29. sector);
  30. return 0;
  31. }
  32. /* Get the read to the beginning of a partition */
  33. sector += byte_offset >> log2blksz;
  34. byte_offset &= blk->blksz - 1;
  35. log_debug(" <" LBAFU ", %d, %d>\n", sector, byte_offset, byte_len);
  36. if (byte_offset != 0) {
  37. int readlen;
  38. /* read first part which isn't aligned with start of sector */
  39. if (blk_dread(blk, partition->start + sector, 1,
  40. (void *)sec_buf) != 1) {
  41. log_err(" ** %s read error **\n", __func__);
  42. return 0;
  43. }
  44. readlen = min((int)blk->blksz - byte_offset,
  45. byte_len);
  46. memcpy(buf, sec_buf + byte_offset, readlen);
  47. buf += readlen;
  48. byte_len -= readlen;
  49. sector++;
  50. }
  51. if (byte_len == 0)
  52. return 1;
  53. /* read sector aligned part */
  54. block_len = byte_len & ~(blk->blksz - 1);
  55. if (block_len == 0) {
  56. ALLOC_CACHE_ALIGN_BUFFER(u8, p, blk->blksz);
  57. block_len = blk->blksz;
  58. blk_dread(blk, partition->start + sector, 1,
  59. (void *)p);
  60. memcpy(buf, p, byte_len);
  61. return 1;
  62. }
  63. if (blk_dread(blk, partition->start + sector,
  64. block_len >> log2blksz, (void *)buf) !=
  65. block_len >> log2blksz) {
  66. log_err(" ** %s read error - block\n", __func__);
  67. return 0;
  68. }
  69. block_len = byte_len & ~(blk->blksz - 1);
  70. buf += block_len;
  71. byte_len -= block_len;
  72. sector += block_len / blk->blksz;
  73. if (byte_len != 0) {
  74. /* read rest of data which are not in whole sector */
  75. if (blk_dread(blk, partition->start + sector, 1,
  76. (void *)sec_buf) != 1) {
  77. log_err("* %s read error - last part\n", __func__);
  78. return 0;
  79. }
  80. memcpy(buf, sec_buf, byte_len);
  81. }
  82. return 1;
  83. }