Add "volume" option to boot images from other partitions

Author: stephan-gh

boot.c

@@ -1289,6 +1289,7 @@ static VOID config_entry_add_from_file(
         entry = AllocatePool(sizeof(ConfigEntry));
 
         *entry = (ConfigEntry) {
+                .device = device,
                 .tries_done = (UINTN) -1,
                 .tries_left = (UINTN) -1,
         };
@@ -1375,6 +1376,17 @@ static VOID config_entry_add_from_file(
 
                         continue;
                 }
+
+                if (strcmpa((CHAR8 *)"volume", key) == 0) {
+                        EFI_GUID volume;
+                        EFI_HANDLE *new;
+                        if (EFI_ERROR(parse_guid(value, &volume)))
+                                continue;
+                        if (EFI_ERROR(disk_find_by_part_uuid(&new, &volume)))
+                                continue;
+
+                        entry->device = new;
+                }
         }
 
         if (entry->type == LOADER_UNDEFINED) {
@@ -1396,7 +1408,6 @@ static VOID config_entry_add_from_file(
                 }
         }
 
-        entry->device = device;
         entry->id = StrDuplicate(file);
         len = StrLen(entry->id);
         /* remove ".conf" */

disk.c

@@ -33,3 +33,19 @@ EFI_STATUS disk_get_part_uuid(EFI_HANDLE *handle, CHAR16 uuid[static 37]) {
 
         return EFI_NOT_FOUND;
 }
+
+EFI_STATUS disk_find_by_part_uuid(EFI_HANDLE **handle, EFI_GUID *guid) {
+        UINTN handle_no;
+        _cleanup_freepool_ EFI_HANDLE *handles = NULL;
+        EFI_STATUS err = LibLocateHandleByDiskSignature(
+                                MBR_TYPE_EFI_PARTITION_TABLE_HEADER, SIGNATURE_TYPE_GUID,
+                                guid, &handle_no, &handles);
+        if (EFI_ERROR(err))
+                return err;
+
+        if (handle_no == 0)
+                return EFI_NOT_FOUND;
+
+        *handle = handles[0];
+        return EFI_SUCCESS;
+}

disk.h

@@ -2,3 +2,4 @@
 #pragma once
 
 EFI_STATUS disk_get_part_uuid(EFI_HANDLE *handle, CHAR16 uuid[static 37]);
+EFI_STATUS disk_find_by_part_uuid(EFI_HANDLE **handle, EFI_GUID *guid);

util.c

@@ -82,6 +82,55 @@ EFI_STATUS parse_boolean(const CHAR8 *v, BOOLEAN *b) {
         return EFI_INVALID_PARAMETER;
 }
 
+#define DECLARE_PARSE_HEX(n)\
+static BOOLEAN parse_hex##n(const CHAR8 **input, UINT##n *u) {\
+        UINTN i; CHAR8 c;\
+        for (i = 0; i < sizeof(UINT##n) * 2; ++i) {\
+                c = *((*input)++);\
+                if (c >= '0' && c <= '9')\
+                        *u = *u << 4 | (c - '0');\
+                else if (c >= 'A' && c <= 'F')\
+                        *u = *u << 4 | (c - 'A' + 10);\
+                else if (c >= 'a' && c <= 'f')\
+                        *u = *u << 4 | (c - 'a' + 10);\
+                else{\
+                        return FALSE;\
+                }\
+        }\
+        return TRUE;\
+}
+
+DECLARE_PARSE_HEX(8)
+DECLARE_PARSE_HEX(16)
+DECLARE_PARSE_HEX(32)
+
+#define GUID_LENGTH  36
+#define CHECK_DASH(input) *((input)++) == '-'
+
+EFI_STATUS parse_guid(const CHAR8 *input, EFI_GUID *guid) {
+        if (strlena(input) != GUID_LENGTH) {
+                return EFI_INVALID_PARAMETER;
+        }
+
+        if (parse_hex32(&input, &guid->Data1)
+                && CHECK_DASH(input) && parse_hex16(&input, &guid->Data2)
+                && CHECK_DASH(input) && parse_hex16(&input, &guid->Data3)
+                && CHECK_DASH(input)
+                        && parse_hex8(&input, &guid->Data4[0])
+                        && parse_hex8(&input, &guid->Data4[1])
+                && CHECK_DASH(input)) {
+
+                UINTN i;
+                for (i = 2; i < 8; ++i)
+                        if (!parse_hex8(&input, &guid->Data4[i]))
+                                return EFI_INVALID_PARAMETER;
+
+                return EFI_SUCCESS;
+        }
+
+        return EFI_INVALID_PARAMETER;
+}
+
 EFI_STATUS efivar_set_raw(const EFI_GUID *vendor, const CHAR16 *name, const VOID *buf, UINTN size, BOOLEAN persistent) {
         UINT32 flags;
 

util.h

@@ -12,6 +12,7 @@ static inline const CHAR16 *yes_no(BOOLEAN b) {
 }
 
 EFI_STATUS parse_boolean(const CHAR8 *v, BOOLEAN *b);
+EFI_STATUS parse_guid(const CHAR8 *v, EFI_GUID *guid);
 
 UINT64 ticks_read(void);
 UINT64 ticks_freq(void);