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gpt: split out checksum recomputation

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For basic data modifications the full repair function is overkill.
This commit is contained in:
Michael Marineau 2014-11-15 13:27:13 -08:00
parent 6278c3e75f
commit d3c2759e83
2 changed files with 23 additions and 10 deletions
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30
grub-core/lib/gpt.c
View file

@ -293,7 +293,6 @@ grub_err_t
grub_gpt_repair (grub_disk_t disk, grub_gpt_t gpt) grub_gpt_repair (grub_disk_t disk, grub_gpt_t gpt)
{ {
grub_uint64_t backup_header, backup_entries; grub_uint64_t backup_header, backup_entries;
grub_uint32_t crc;
if (disk->log_sector_size != gpt->log_sector_size) if (disk->log_sector_size != gpt->log_sector_size)
return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
@ -331,13 +330,32 @@ grub_gpt_repair (grub_disk_t disk, grub_gpt_t gpt)
gpt->backup.alternate_lba = gpt->primary.header_lba; gpt->backup.alternate_lba = gpt->primary.header_lba;
gpt->backup.partitions = grub_cpu_to_le64 (backup_entries); gpt->backup.partitions = grub_cpu_to_le64 (backup_entries);
/* Recompute checksums. */
if (grub_gpt_update_checksums (gpt))
return grub_errno;
/* Sanity check. */
if (grub_gpt_header_check (&gpt->primary, gpt->log_sector_size))
return grub_error (GRUB_ERR_BUG, "Generated invalid GPT primary header");
if (grub_gpt_header_check (&gpt->backup, gpt->log_sector_size))
return grub_error (GRUB_ERR_BUG, "Generated invalid GPT backup header");
gpt->status |= GRUB_GPT_BOTH_VALID;
return GRUB_ERR_NONE;
}
grub_err_t
grub_gpt_update_checksums (grub_gpt_t gpt)
{
grub_uint32_t crc;
/* Writing headers larger than our header structure are unsupported. */ /* Writing headers larger than our header structure are unsupported. */
gpt->primary.headersize = gpt->primary.headersize =
grub_cpu_to_le32_compile_time (sizeof (gpt->primary)); grub_cpu_to_le32_compile_time (sizeof (gpt->primary));
gpt->backup.headersize = gpt->backup.headersize =
grub_cpu_to_le32_compile_time (sizeof (gpt->backup)); grub_cpu_to_le32_compile_time (sizeof (gpt->backup));
/* Recompute checksums. */
if (grub_gpt_lecrc32 (gpt->entries, gpt->entries_size, &crc)) if (grub_gpt_lecrc32 (gpt->entries, gpt->entries_size, &crc))
return grub_errno; return grub_errno;
@ -350,14 +368,6 @@ grub_gpt_repair (grub_disk_t disk, grub_gpt_t gpt)
if (grub_gpt_header_lecrc32 (&gpt->backup, &gpt->backup.crc32)) if (grub_gpt_header_lecrc32 (&gpt->backup, &gpt->backup.crc32))
return grub_errno; return grub_errno;
/* Sanity check. */
if (grub_gpt_header_check (&gpt->primary, gpt->log_sector_size))
return grub_error (GRUB_ERR_BUG, "Generated invalid GPT primary header");
if (grub_gpt_header_check (&gpt->backup, gpt->log_sector_size))
return grub_error (GRUB_ERR_BUG, "Generated invalid GPT backup header");
gpt->status |= GRUB_GPT_BOTH_VALID;
return GRUB_ERR_NONE; return GRUB_ERR_NONE;
} }

3
include/grub/gpt_partition.h
View file

@ -151,6 +151,9 @@ grub_gpt_t grub_gpt_read (grub_disk_t disk);
/* Sync up primary and backup headers, recompute checksums. */ /* Sync up primary and backup headers, recompute checksums. */
grub_err_t grub_gpt_repair (grub_disk_t disk, grub_gpt_t gpt); grub_err_t grub_gpt_repair (grub_disk_t disk, grub_gpt_t gpt);
/* Recompute checksums, must be called after modifying GPT data. */
grub_err_t grub_gpt_update_checksums (grub_gpt_t gpt);
/* Write headers and entry tables back to disk. */ /* Write headers and entry tables back to disk. */
grub_err_t grub_gpt_write (grub_disk_t disk, grub_gpt_t gpt); grub_err_t grub_gpt_write (grub_disk_t disk, grub_gpt_t gpt);