src/detection/bootmgr/bootmgr_linux.c


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#include "bootmgr.h"
#include "common/io.h"
#include "efi_helper.h"

#include <stdalign.h>

#define FF_EFIVARS_PATH_PREFIX "/sys/firmware/efi/efivars/"

const char* ffDetectBootmgr(FFBootmgrResult* result) {
    alignas(uint16_t) uint8_t buffer[2048];

    if (ffReadFileData(FF_EFIVARS_PATH_PREFIX "BootCurrent-" FF_EFI_GLOBAL_GUID, sizeof(buffer), buffer) != 6) {
        return "Failed to read efivar: BootCurrent";
    }

    result->order = *(uint16_t*) &buffer[4];

    snprintf((char*) buffer, sizeof(buffer), FF_EFIVARS_PATH_PREFIX "Boot%04X-" FF_EFI_GLOBAL_GUID, result->order);

    ssize_t size = ffReadFileData((const char*) buffer, sizeof(buffer), buffer);
    if (size < 5 + (int) sizeof(FFEfiLoadOption) || size == (ssize_t) sizeof(buffer)) {
        return "Failed to read efivar: Boot####";
    }

    ffEfiFillLoadOption((FFEfiLoadOption*) &buffer[4], result);

    if (ffReadFileData(FF_EFIVARS_PATH_PREFIX "SecureBoot-" FF_EFI_GLOBAL_GUID, sizeof(buffer), buffer) >= 5) {
        result->secureBoot = buffer[4] == 1;
    }

    return NULL;
}