Add Android loader type that automatically configures android.efi

Like the Linux boot type, this is just syntactic sugar for an EFI
application (here: android-efi) that is expected to be present in
the root directory of the ESP partition.

For example:

    title    Android
    android  80868086-8086-8086-8086-000000000100
    initrd   /intel-ucode.img
    options  androidboot.mode=charger

translates to

    title    Android
    efi      /android.efi
    options  android 80868086-8086-8086-8086-000000000100 -- initrd=/intel-ucode.img androidboot.mode=charger

Author: stephan-gh

boot.c

@@ -27,6 +27,7 @@ enum loader_type {
         LOADER_UNDEFINED,
         LOADER_EFI,
         LOADER_LINUX,
+        LOADER_ANDROID,
 };
 
 typedef struct {
@@ -1321,6 +1322,14 @@ static VOID config_entry_add_from_file(
                         continue;
                 }
 
+                if (strcmpa((CHAR8 *)"android", key) == 0) {
+                        FreePool(entry->loader);
+                        entry->type = LOADER_ANDROID;
+                        entry->loader = stra_to_str(value);
+                        entry->key = 'a';
+                        continue;
+                }
+
                 if (strcmpa((CHAR8 *)"efi", key) == 0) {
                         entry->type = LOADER_EFI;
                         FreePool(entry->loader);
@@ -1395,7 +1404,7 @@ static VOID config_entry_add_from_file(
         }
 
         /* add initrd= to options */
-        if (entry->type == LOADER_LINUX && initrd) {
+        if ((entry->type == LOADER_LINUX || entry->type == LOADER_ANDROID) && initrd) {
                 if (entry->options) {
                         CHAR16 *s;
 
@@ -1415,6 +1424,24 @@ static VOID config_entry_add_from_file(
                 entry->id[len - 5] = '\0';
         StrLwr(entry->id);
 
+        if (entry->type == LOADER_ANDROID) {
+                if (entry->loader) {
+                        CHAR16 *s;
+                        if (entry->options) {
+                                s = PoolPrint(L"%s %s -- %s", entry->id,
+                                        entry->loader, entry->options);
+                                FreePool(entry->options);
+                        } else {
+                                s = PoolPrint(L"%s %s",
+                                        entry->id, entry->loader);
+                        }
+                        entry->options = s;
+                        FreePool(entry->loader);
+                }
+
+                entry->loader = L"" ANDROID_EFI_PATH;
+        }
+
         config_add_entry(config, entry);
 
         config_entry_parse_tries(entry, path, file, L".conf");

meson.build

@@ -113,6 +113,7 @@ if have_gnu_efi
         efi_conf.set_quoted('EFI_MACHINE_TYPE_NAME', EFI_MACHINE_TYPE_NAME)
         efi_conf.set10('ENABLE_TPM', get_option('tpm'))
         efi_conf.set('SD_TPM_PCR', get_option('tpm-pcrindex'))
+        efi_conf.set_quoted('ANDROID_EFI_PATH', '\\\\'.join(get_option('android-efi').split('/')))
 
         efi_config_h = configure_file(
                 output : 'efi_config.h',

meson_options.txt

@@ -18,6 +18,8 @@ option('efi-includedir', type : 'string', value : '/usr/include/efi',
        description : 'path to the EFI header directory')
 option('tpm-pcrindex', type : 'integer', value : 8,
        description : 'TPM PCR register number to use')
+option('android-efi', type : 'string', value : '/android.efi',
+       description : 'Path to android.efi binary for booting Android images (optional)')
 
 option('tests', type : 'combo', choices : ['true', 'false'],
        description : 'enable tests')