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authorPierre-Alexandre Meyer <pierre@mouraf.org>2009-08-04 17:35:32 -0700
committerPierre-Alexandre Meyer <pierre@mouraf.org>2009-08-04 17:35:32 -0700
commita6b80d3e8a356a55b4365c5e402e502843bbff8c (patch)
treea9e92742895618e608078c21d0309ea417ea1682 /com32
parenta3a51af1381b1abbbf82484b3258955f7d1e79f8 (diff)
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gpllib: refactor partitions detection
Re-implement the logic to parse extended partitions to correctly go through the linked list of partitions. Updated the CLI in hdt and tested it both on Qemu (Debian Lenny installation) and on DELL E6400 (6 partitions). The output seemed sane. Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
Diffstat (limited to 'com32')
-rw-r--r--com32/gpllib/disk/msdos.c107
-rw-r--r--com32/hdt/hdt-cli-disk.c11
2 files changed, 53 insertions, 65 deletions
diff --git a/com32/gpllib/disk/msdos.c b/com32/gpllib/disk/msdos.c
index 9bfcacca..3b31dd0d 100644
--- a/com32/gpllib/disk/msdos.c
+++ b/com32/gpllib/disk/msdos.c
@@ -29,67 +29,62 @@ static inline int msdos_magic_present(char *ptab)
}
/**
- * process_ebr - execute a callback for each partition contained in an ebr
- * @drive_info: driveinfo struct describing the drive
- * @ptab_root: part_entry struct describing the root partition (pointing to the ebr)
- * @ebr_seen: Number of ebr processed
- * @callback: Callback to execute
+ * process_extended_partition - execute a callback for each partition contained listed in an ebr
+ * @drive_info: driveinfo struct describing the drive
+ * @partition_offset: Absolute start (lba) of the partition
+ * @callback: Callback to execute
+ * @error: Buffer for I/O errors
+ * @nb_part_seen: Number of partitions found on the disk so far
**/
-static void process_ebr(struct driveinfo *drive_info, struct part_entry *ptab_root,
- int ebr_seen,
- void *callback(struct driveinfo *, struct part_entry *, struct part_entry *, int, int, int),
- int *error, int offset_root)
+static void process_extended_partition(struct driveinfo *drive_info,
+ int partition_offset,
+ void *callback(struct driveinfo *, struct part_entry *, int, int),
+ int *error, int nb_part_seen)
{
/* The ebr is located at the first sector of the extended partition */
- char* ebr = read_sectors(drive_info, ptab_root->start_lba+offset_root, 1, error);
- if (!ebr)
+ char* ebr = read_sectors(drive_info, partition_offset, 1, error);
+
+ /* If something bad during the read happens, we can't do much: bail out */
+ if (*error)
return;
/* Check msdos magic signature */
- if(!msdos_magic_present(ebr))
+ if (!msdos_magic_present(ebr))
return;
- ebr_seen += 1;
- struct part_entry *ptab_child = (struct part_entry *)(ebr + PARTITION_TABLES_OFFSET);
+ struct part_entry *ptab = (struct part_entry *)(ebr + PARTITION_TABLES_OFFSET);
- /* First process the data partitions */
for (int i = 0; i < 4; i++) {
- if (*error)
- return;
+ if (!is_extended_partition(&ptab[i])) {
+ /*
+ * This EBR partition table entry points to the
+ * logical partition associated to that EBR
+ */
+ int logical_partition_start = partition_offset + ptab[i].start_lba;
- if (ptab_child[i].start_sect > 0) {
- if (is_extended_partition(&ptab_child[i])) {
+ /* Last EBR in the extended partition? */
+ if (!logical_partition_start)
continue;
- }
- /* Check for garbage in the 3rd and 4th entries */
- if (i > 2) {
- unsigned int offset = ptab_child->start_lba + ptab_root->start_lba;
- if ( offset + ptab_child->length <= ptab_root->start_lba ||
- offset >= ptab_root->start_lba + ptab_root->length ) {
- continue;
- }
- }
- callback(drive_info,
- &ptab_child[i],
- ptab_root,
- offset_root,
- i,
- ebr_seen);
- }
- }
+ /*
+ * Check for garbage:
+ * 3rd and 4th entries in an EBR should be zero
+ * Some (malformed) partitioning software still add some
+ * data partitions there.
+ */
+ if (ptab[i].start_lba <= 0 || ptab[i].length <= 0)
+ continue;
- /* Now process the extended partitions */
- for (int i = 0; i < 4; i++) {
- if (is_extended_partition(&ptab_child[i])) {
+ nb_part_seen++;
callback(drive_info,
- &ptab_child[i],
- ptab_root,
- offset_root,
- i,
- ebr_seen);
- process_ebr(drive_info, &ptab_child[i], ebr_seen + 1, callback, error, ptab_root->start_lba);
- }
+ &ptab[i],
+ logical_partition_start,
+ nb_part_seen);
+ } else
+ process_extended_partition(drive_info,
+ partition_offset + ptab[i].start_lba,
+ callback,
+ error, nb_part_seen);
}
}
@@ -101,7 +96,7 @@ static void process_ebr(struct driveinfo *drive_info, struct part_entry *ptab_ro
* @error: Return the error code (I/O), if needed
**/
static void process_mbr(struct driveinfo *drive_info, struct part_entry *ptab,
- void *callback(struct driveinfo *, struct part_entry *, struct part_entry *, int, int, int),
+ void *callback(struct driveinfo *, struct part_entry *, int, int),
int *error)
{
for (int i = 0; i < 4; i++) {
@@ -112,18 +107,14 @@ static void process_mbr(struct driveinfo *drive_info, struct part_entry *ptab,
if (is_extended_partition(&ptab[i])) {
callback(drive_info,
&ptab[i],
- ptab,
- 0,
- i,
- 0);
- process_ebr(drive_info, &ptab[i], 0, callback, error, 0);
+ ptab[i].start_lba,
+ i+1);
+ process_extended_partition(drive_info, ptab[i].start_lba, callback, error, 4);
} else
callback(drive_info,
&ptab[i],
- ptab,
- 0,
- i,
- 0);
+ ptab[i].start_lba,
+ i+1);
}
}
}
@@ -138,10 +129,8 @@ static void process_mbr(struct driveinfo *drive_info, struct part_entry *ptab,
*
* void callback(struct driveinfo *drive_info,
* struct part_entry *ptab,
- * struct part_entry *ptab_root,
* int offset_root,
- * int local_partition_number,
- * int ebr_seen)
+ * int nb_part_seen)
**/
int parse_partition_table(struct driveinfo *d, void *callback, int *error)
{
diff --git a/com32/hdt/hdt-cli-disk.c b/com32/hdt/hdt-cli-disk.c
index 3209c8b1..8e07ed08 100644
--- a/com32/hdt/hdt-cli-disk.c
+++ b/com32/hdt/hdt-cli-disk.c
@@ -58,9 +58,8 @@
**/
static void show_partition_information(struct driveinfo *drive_info,
struct part_entry *ptab,
- struct part_entry *ptab_root,
- int offset_root, int data_partitions_seen,
- int ebr_seen)
+ int partition_offset,
+ int nb_partitions_seen)
{
char size[8];
char *parttype;
@@ -68,10 +67,10 @@ static void show_partition_information(struct driveinfo *drive_info,
char *error_buffer;
unsigned int start, end;
- int i = 1 + ebr_seen * 4 + data_partitions_seen;
+ int i = nb_partitions_seen;
- start = ptab->start_lba + ptab_root->start_lba + offset_root;
- end = (ptab->start_lba + ptab_root->start_lba) + ptab->length + offset_root;
+ start = partition_offset;
+ end = start + ptab->length;
if (ptab->length > 0)
sectors_to_size(ptab->length, size);