WiFi Interface 的 name 如何获取到

直接计算在 wifi_chip.cpp 中

std::string getWlanIfaceName(unsigned idx) {
    if (idx >= kMaxWlanIfaces) {
        CHECK(false) << "Requested interface beyond wlan" << kMaxWlanIfaces;
        return {};
    }

    std::array<char, PROPERTY_VALUE_MAX> buffer;
    if (idx == 0 || idx == 1) {
        const char* altPropName =
            (idx == 0) ? "wifi.interface" : "wifi.concurrent.interface";
        auto res = property_get(altPropName, buffer.data(), nullptr);
        if (res > 0) return buffer.data();
    }
    std::string propName = "wifi.interface." + std::to_string(idx);
    auto res = property_get(propName.c_str(), buffer.data(), nullptr);
    if (res > 0) return buffer.data();

    return "wlan" + std::to_string(idx);
}

返回了 wlanN 字串，其调用发生在 allocateApOrStaIfaceName 接口

/* wifi_chip.cpp */
// Return the first wlan (wlan0, wlan1 etc.) starting from |start_idx|
// not already in use.
// Note: This doesn't check the actual presence of these interfaces.
std::string WifiChip::allocateApOrStaIfaceName(uint32_t start_idx) {
    for (unsigned idx = start_idx; idx < kMaxWlanIfaces; idx++) {
        const auto ifname = getWlanIfaceName(idx);
        if (findUsingName(ap_ifaces_, ifname)) continue;
        if (findUsingName(sta_ifaces_, ifname)) continue;
        return ifname;
    }
    // This should never happen. We screwed up somewhere if it did.
    CHECK(false) << "All wlan interfaces in use already!";
    return {};
}

继续回溯：allocateStaIfaceName

/* wifi_chip.cpp */
// STA iface names start with idx 0.
// Primary STA iface will always be 0.
std::string WifiChip::allocateStaIfaceName() {
    return allocateApOrStaIfaceName(0);
}

createStaIface -> createStaIfaceInternal

/* wifi_chip.cpp */
Return<void> WifiChip::createStaIface(createStaIface_cb hidl_status_cb) {
    return validateAndCall(this, WifiStatusCode::ERROR_WIFI_CHIP_INVALID,
                           &WifiChip::createStaIfaceInternal, hidl_status_cb);
}

std::pair<WifiStatus, sp<V1_3::IWifiStaIface>>
WifiChip::createStaIfaceInternal() {
    if (!canCurrentModeSupportIfaceOfTypeWithCurrentIfaces(IfaceType::STA)) {
        return {createWifiStatus(WifiStatusCode::ERROR_NOT_AVAILABLE), {}};
    }
    std::string ifname = allocateStaIfaceName();
    legacy_hal::wifi_error legacy_status =
        legacy_hal_.lock()->createVirtualInterface(
            ifname,
            hidl_struct_util::convertHidlIfaceTypeToLegacy(IfaceType::STA));
    if (legacy_status != legacy_hal::WIFI_SUCCESS) {
        LOG(ERROR) << "Failed to add interface: " << ifname << " "
                   << legacyErrorToString(legacy_status);
        return {createWifiStatusFromLegacyError(legacy_status), {}};
    }
    sp<WifiStaIface> iface = new WifiStaIface(ifname, legacy_hal_, iface_util_);
    sta_ifaces_.push_back(iface);
    for (const auto& callback : event_cb_handler_.getCallbacks()) {
        if (!