ro.boot.bootreason property设置(androidboot.xxxx bootargs)

static void process_kernel_cmdline() {
    // The first pass does the common stuff, and finds if we are in qemu.
    // The second pass is only necessary for qemu to export all kernel params
    // as properties.
    import_kernel_cmdline(false, import_kernel_nv);
    if (qemu[0]) import_kernel_cmdline(true, import_kernel_nv);
}

static void import_kernel_nv(const std::string& key, const std::string& value, bool for_emulator) {
    if (key.empty()) return;

    if (for_emulator) {
        // In the emulator, export any kernel option with the "ro.kernel." prefix.
        property_set("ro.kernel." + key, value);
        return;
    }

    if (key == "qemu") {
        strlcpy(qemu, value.c_str(), sizeof(qemu));
    } else if (android::base::StartsWith(key, "androidboot.")) {
        property_set("ro.boot." + key.substr(12), value);
    }
}

void SetSystemBootReason() {
  const auto bootloader_boot_reason =
      android::base::GetProperty(bootloader_reboot_reason_property, "");
  const std::string system_boot_reason(BootReasonStrToReason(bootloader_boot_reason));
  // Record the scrubbed system_boot_reason to the property
  BootReasonAddToHistory(system_boot_reason);