Files
Limine/common/protos/efi_boot_entry.c

131 lines
3.9 KiB
C

#include <protos/efi_boot_entry.h>
#if defined(UEFI)
#include <mm/pmm.h>
#include <efi.h>
#include <lib/config.h>
#include <lib/misc.h>
#include <stdbool.h>
static bool uefi_string_matches(CHAR16 *desc, size_t desc_max_chars, CHAR16 *target) {
while (*target) {
if (desc_max_chars == 0)
return false;
CHAR16 a = *desc >= L'a' && *desc <= L'z' ? *desc - 32 : *desc;
CHAR16 b = *target >= L'a' && *target <= L'z' ? *target - 32 : *target;
if (a != b)
return false;
desc++;
target++;
desc_max_chars--;
}
return desc_max_chars > 0 && *desc == L'\0';
}
static void format_boot_var(CHAR16 *out, UINT16 num) {
out[0] = L'B';
out[1] = L'o';
out[2] = L'o';
out[3] = L't';
out[4] = L"0123456789ABCDEF"[(num >> 12) & 0xF];
out[5] = L"0123456789ABCDEF"[(num >> 8) & 0xF];
out[6] = L"0123456789ABCDEF"[(num >> 4) & 0xF];
out[7] = L"0123456789ABCDEF"[(num >> 0) & 0xF];
out[8] = L'\0';
}
static bool find_boot_entry(CHAR16 *entry, uint16_t *out) {
EFI_STATUS status;
uint16_t boot_order[128];
size_t size = sizeof(boot_order);
EFI_GUID global_variable = EFI_GLOBAL_VARIABLE;
status = gRT->GetVariable(L"BootOrder", &global_variable, NULL, &size, boot_order);
if (EFI_ERROR(status)) {
panic(true, "efi_boot_entry: Failed to get BootOrder variable (%X)",
(uint64_t)status);
}
size_t count = size / sizeof(uint16_t);
for (size_t i = 0; i < count; i++) {
CHAR16 var_name[9];
format_boot_var(var_name, boot_order[i]);
size_t buf_size = 0;
/* Query for buf size */
gRT->GetVariable(var_name, &global_variable, NULL, &buf_size, NULL);
uint8_t *buf = ext_mem_alloc(buf_size);
status = gRT->GetVariable(var_name, &global_variable, NULL, &buf_size, buf);
if (EFI_ERROR(status)) {
pmm_free(buf, buf_size);
continue;
}
/* Get the description */
if (buf_size < sizeof(uint32_t) + sizeof(uint16_t) + sizeof(CHAR16)) {
pmm_free(buf, buf_size);
continue;
}
size_t desc_offset = sizeof(uint32_t) + sizeof(uint16_t);
CHAR16 *desc = (CHAR16 *)(buf + desc_offset);
size_t desc_max_chars = (buf_size - desc_offset) / sizeof(CHAR16);
if (uefi_string_matches(desc, desc_max_chars, entry)) {
*out = boot_order[i];
pmm_free(buf, buf_size);
return true;
}
pmm_free(buf, buf_size);
}
return false;
}
noreturn void efi_boot_entry(char *config) {
char *boot_entry = config_get_value(config, 0, "ENTRY");
if (boot_entry == NULL) {
panic(true, "efi_boot_entry: No entry specified");
}
/* Convert entry string to UTF-16 */
CHAR16 boot_entry_utf16[128];
size_t i;
for (i = 0; i < sizeof(boot_entry_utf16) / sizeof(CHAR16) - 1 && boot_entry[i]; i++) {
boot_entry_utf16[i] = (CHAR16)boot_entry[i];
}
boot_entry_utf16[i] = L'\0';
/* Find the desired boot entry */
uint16_t boot_next = 0;
if (!find_boot_entry(boot_entry_utf16, &boot_next)) {
panic(true, "efi_boot_entry: Failed to find boot entry '%s'", boot_entry);
}
EFI_GUID global_variable = EFI_GLOBAL_VARIABLE;
/* Set BootNext to it */
EFI_STATUS status = gRT->SetVariable(L"BootNext", &global_variable,
EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS,
sizeof(boot_next), &boot_next);
if (status) {
panic(true, "efi_boot_entry: Failed to set BootNext variable (%X)",
(uint64_t)status);
}
/* Now reboot */
gRT->ResetSystem(EfiResetWarm, EFI_SUCCESS, 0, NULL);
panic(true, "efi_boot_entry: Failed to reboot");
}
#endif