[PATCH 04/16] part: detect EFI system partition

Heinrich Schuchardt
2020-03-27T05:27:48Z

Up to now for MBR and GPT partitions the info field 'bootable' was set to 1
if either the partition was an EFI system partition or the bootable flag
was set.

Turn info field 'bootable' into a bit mask with separate bits for bootable
and EFI system partition.

This will allow us to identify the EFI system partition in the UEFI
sub-system.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
disk/part_dos.c | 10 ++++++++--
disk/part_efi.c | 12 ++++++++----
include/part.h | 11 ++++++++++-
3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/disk/part_dos.c b/disk/part_dos.c
index 83ff40d310..0ec7f1628e 100644
--- a/disk/part_dos.c
+++ b/disk/part_dos.c
@@ -45,9 +45,15 @@ static inline int is_extended(int part_type)
part_type == 0x85);
}

-static inline int is_bootable(dos_partition_t *p)
+static int is_bootable(dos_partition_t *p)
{
- return (p->sys_ind == 0xef) || (p->boot_ind == 0x80);
+ int ret = 0;
+
+ if (p->sys_ind == 0xef)
+ ret |= PART_EFI_SYSTEM_PARTITION;
+ if (p->boot_ind == 0x80)
+ ret |= PART_BOOTABLE;
+ return ret;
}

static void print_one_part(dos_partition_t *p, lbaint_t ext_part_sector,
diff --git a/disk/part_efi.c b/disk/part_efi.c
index b2e157d9c1..19f1f43f4e 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -71,11 +71,15 @@ static char *print_efiname(gpt_entry *pte)

static const efi_guid_t system_guid = PARTITION_SYSTEM_GUID;

-static inline int is_bootable(gpt_entry *p)
+static int is_bootable(gpt_entry *p)
{
- return p->attributes.fields.legacy_bios_bootable ||
- !memcmp(&(p->partition_type_guid), &system_guid,
- sizeof(efi_guid_t));
+ int ret = 0;
+
+ if (!memcmp(&p->partition_type_guid, &system_guid, sizeof(efi_guid_t)))
+ ret |= PART_EFI_SYSTEM_PARTITION;
+ if (p->attributes.fields.legacy_bios_bootable)
+ ret |= PART_BOOTABLE;
+ return ret;
}

static int validate_gpt_header(gpt_header *gpt_h, lbaint_t lba,
diff --git a/include/part.h b/include/part.h
index 0b5cf3d5e8..a63d1d0cda 100644
--- a/include/part.h
+++ b/include/part.h
@@ -51,13 +51,22 @@ struct block_drvr {
#define PART_TYPE_LEN 32
#define MAX_SEARCH_PARTITIONS 64

+#define PART_BOOTABLE 1
+#define PART_EFI_SYSTEM_PARTITION 2
+
typedef struct disk_partition {
lbaint_t start; /* # of first block in partition */
lbaint_t size; /* number of blocks in partition */
ulong blksz; /* block size in bytes */
uchar name[PART_NAME_LEN]; /* partition name */
uchar type[PART_TYPE_LEN]; /* string type description */
- int bootable; /* Active/Bootable flag is set */
+ /*
+ * The bootable is a bitmask with the following fields:
+ *
+ * PART_BOOTABLE the MBR bootable flag is set
+ * PART_EFI_SYSTEM_PARTITION the partition is an EFI system partition
+ */
+ int bootable;
#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
char uuid[UUID_STR_LEN + 1]; /* filesystem UUID as string, if exists */
#endif
--
2.25.1