disklib: fix extended partition code

gert1 reported some issues using disklib with HDT. As it turned out, the
code that iterated through ebrs in an extended partition was broken: ebr offsets
need to be relative to the start of that partition.

Misc.: fix memory leak.

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
Signed-off-by: Erwan Velu <erwan.velu@free.fr>

diff --git a/com32/gpllib/disk/msdos.c b/com32/gpllib/disk/msdos.c
index e69aa71..1d1ef4d 100644 (file)
--- a/com32/gpllib/disk/msdos.c
+++ b/com32/gpllib/disk/msdos.c
@@ -34,39 +34,42 @@ static inline int msdos_magic_present(const char *ptab)
 /**
  * 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
+ * @partition_offset:  Absolute start (lba) of the extended partition
+ * @ebr_offset:                Relative start (lba) of the current ebr processed within
+ *                     the extended partition
  * @callback:          Callback to execute
  * @error:             Buffer for I/O errors
  * @nb_part_seen:      Number of partitions found on the disk so far
  **/
 static int process_extended_partition(struct driveinfo *drive_info,
-                                      int partition_offset,
-                                      p_callback callback,
-                                      int nb_part_seen)
+                                     const int partition_offset,
+                                     const int ebr_offset,
+                                     p_callback callback,
+                                     int nb_part_seen)
 {
        int status = 0;
        /* The ebr is located at the first sector of the extended partition */
        char* ebr = malloc(SECTOR * sizeof(char));
 
-       if (read_sectors(drive_info, ebr, partition_offset, 1) == -1)
-               return -1;
+       if (read_sectors(drive_info, ebr, partition_offset + ebr_offset, 1) == -1)
+               goto abort;
 
        /* Check msdos magic signature */
        if (!msdos_magic_present(ebr))
-               return -1;
+               goto abort;
 
        struct part_entry *ptab = (struct part_entry *)(ebr + PARTITION_TABLES_OFFSET);
 
        for (int i = 0; i < 4; i++) {
                if (status == -1)
-                       return -1;
+                       goto abort;
 
                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;
+                       int logical_partition_start = ebr_offset + ptab[i].start_lba;
 
                        /* Last EBR in the extended partition? */
                        if (!logical_partition_start)
@@ -84,16 +87,22 @@ static int process_extended_partition(struct driveinfo *drive_info,
                        nb_part_seen++;
                        callback(drive_info,
                                 &ptab[i],
-                                logical_partition_start,
+                                partition_offset + logical_partition_start,
                                 nb_part_seen);
                } else
                        status = process_extended_partition(drive_info,
-                                                  partition_offset + ptab[i].start_lba,
+                                                  partition_offset,
+                                                  ptab[i].start_lba,
                                                   callback,
                                                   nb_part_seen);
        }
 
+       free(ebr);
        return 0;
+
+abort:
+       free(ebr);
+       return -1;
 }
 
 /**
@@ -117,7 +126,7 @@ static int process_mbr(struct driveinfo *drive_info, struct part_entry *ptab,
                                         &ptab[i],
                                         ptab[i].start_lba,
                                         i+1);
-                               status = process_extended_partition(drive_info, ptab[i].start_lba, callback, 4);
+                               status = process_extended_partition(drive_info, ptab[i].start_lba, 0, callback, 4);
                        } else
                                callback(drive_info,
                                         &ptab[i],