[adb] Correctly read host/user name on Windows.

Bug: 162111908

Test: On linux/mac:
HOSTNAME="" adb keygen mykey; cat mykey.pub # Also LOGNAME
HOSTNAME="测试" adb keygen mykey; cat mykey.pub
HOSTNAME="test" adb keygen mykey; cat mykey.pub

Test: On Windows:
set COMPUTERNAME=&& adb keygen mykey
&& powershell -command "get-content -encoding utf8 mykey.pub" # Also USERNAME
set COMPUTERNAME=测试&& adb keygen mykey
&& powershell -command "get-content -encoding utf8 mykey.pub"
set COMPUTERNAME=test&& adb keygen mykey
&& powershell -command "get-content -encoding utf8 mykey.pub"

Change-Id: I62c952c511a620286aa4e05b1763361406e9f89a

adb/Android.bp

@@ -117,6 +117,7 @@ cc_defaults {
     static_libs: [
         "libadb_crypto",
         "libadb_pairing_connection",
+        "libadb_sysdeps",
         "libadb_tls_connection",
         "libadbd",
         "libadbd_core",
@@ -167,6 +168,7 @@ libadb_srcs = [
     "services.cpp",
     "sockets.cpp",
     "socket_spec.cpp",
+    "sysdeps/env.cpp",
     "sysdeps/errno.cpp",
     "transport.cpp",
     "transport_fd.cpp",
@@ -261,6 +263,43 @@ cc_library_host_static {
     ],
 }
 
+cc_library {
+    name: "libadb_sysdeps",
+    defaults: ["adb_defaults"],
+    recovery_available: true,
+    host_supported: true,
+    compile_multilib: "both",
+    min_sdk_version: "apex_inherit",
+
+    srcs: [
+        "sysdeps/env.cpp",
+    ],
+
+    shared_libs: [
+        "libbase",
+        "liblog",
+    ],
+
+    target: {
+        windows: {
+            enabled: true,
+            ldflags: ["-municode"],
+        },
+    },
+
+    export_include_dirs: ["."],
+
+    visibility: [
+        "//system/core/adb:__subpackages__",
+        "//bootable/recovery/minadbd:__subpackages__",
+    ],
+
+    apex_available: [
+        "com.android.adbd",
+        "test_com.android.adbd",
+    ],
+}
+
 cc_test_host {
     name: "adb_test",
     defaults: ["adb_defaults"],
@@ -274,6 +313,7 @@ cc_test_host {
         "libadb_pairing_auth_static",
         "libadb_pairing_connection_static",
         "libadb_protos_static",
+        "libadb_sysdeps",
         "libadb_tls_connection_static",
         "libbase",
         "libcutils",
@@ -330,6 +370,7 @@ cc_binary_host {
         "libadb_pairing_auth",
         "libadb_pairing_connection",
         "libadb_protos",
+        "libadb_sysdeps",
         "libadb_tls_connection",
         "libandroidfw",
         "libapp_processes_protos_full",
@@ -831,6 +872,7 @@ cc_test_host {
         "libadb_pairing_auth_static",
         "libadb_pairing_connection_static",
         "libadb_protos_static",
+        "libadb_sysdeps",
         "libadb_tls_connection_static",
         "libandroidfw",
         "libbase",

adb/crypto/Android.bp

@@ -48,6 +48,7 @@ cc_defaults {
 
     shared_libs: [
         "libadb_protos",
+        "libadb_sysdeps",
         "libbase",
         "liblog",
         "libcrypto",
@@ -76,5 +77,6 @@ cc_library_static {
 
     static_libs: [
         "libadb_protos_static",
+        "libadb_sysdeps",
     ],
 }

adb/crypto/rsa_2048_key.cpp

@@ -20,32 +20,11 @@
 #include <crypto_utils/android_pubkey.h>
 #include <openssl/bn.h>
 #include <openssl/rsa.h>
+#include <sysdeps/env.h>
 
 namespace adb {
 namespace crypto {
 
-namespace {
-std::string get_user_info() {
-    std::string hostname;
-    if (getenv("HOSTNAME")) hostname = getenv("HOSTNAME");
-#if !defined(_WIN32)
-    char buf[64];
-    if (hostname.empty() && gethostname(buf, sizeof(buf)) != -1) hostname = buf;
-#endif
-    if (hostname.empty()) hostname = "unknown";
-
-    std::string username;
-    if (getenv("LOGNAME")) username = getenv("LOGNAME");
-#if !defined(_WIN32)
-    if (username.empty() && getlogin()) username = getlogin();
-#endif
-    if (username.empty()) hostname = "unknown";
-
-    return " " + username + "@" + hostname;
-}
-
-}  // namespace
-
 bool CalculatePublicKey(std::string* out, RSA* private_key) {
     uint8_t binary_key_data[ANDROID_PUBKEY_ENCODED_SIZE];
     if (!android_pubkey_encode(private_key, binary_key_data, sizeof(binary_key_data))) {
@@ -63,7 +42,10 @@ bool CalculatePublicKey(std::string* out, RSA* private_key) {
     size_t actual_length = EVP_EncodeBlock(reinterpret_cast<uint8_t*>(out->data()), binary_key_data,
                                            sizeof(binary_key_data));
     out->resize(actual_length);
-    out->append(get_user_info());
+    out->append(" ");
+    out->append(sysdeps::GetLoginNameUTF8());
+    out->append("@");
+    out->append(sysdeps::GetHostNameUTF8());
     return true;
 }
 

adb/crypto/tests/Android.bp

@@ -35,6 +35,7 @@ cc_test {
     static_libs: [
         "libadb_crypto_static",
         "libadb_protos_static",
+        "libadb_sysdeps",
     ],
 
     test_suites: ["device-tests"],

adb/sysdeps/env.cpp

@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "sysdeps/env.h"
+
+#ifdef _WIN32
+#include <lmcons.h>
+#include <windows.h>
+#endif  // _WIN32
+
+#include <android-base/utf8.h>
+
+namespace adb {
+namespace sysdeps {
+
+std::optional<std::string> GetEnvironmentVariable(std::string_view var) {
+    if (var.empty()) {
+        return std::nullopt;
+    }
+
+#ifdef _WIN32
+    constexpr size_t kMaxEnvVarSize = 32767;
+    wchar_t wbuf[kMaxEnvVarSize];
+    std::wstring wvar;
+    if (!android::base::UTF8ToWide(var.data(), &wvar)) {
+        return std::nullopt;
+    }
+
+    auto sz = ::GetEnvironmentVariableW(wvar.data(), wbuf, sizeof(wbuf));
+    if (sz == 0) {
+        return std::nullopt;
+    }
+
+    std::string val;
+    if (!android::base::WideToUTF8(wbuf, &val)) {
+        return std::nullopt;
+    }
+
+    return std::make_optional(val);
+#else  // !_WIN32
+    const char* val = getenv(var.data());
+    if (val == nullptr) {
+        return std::nullopt;
+    }
+
+    return std::make_optional(std::string(val));
+#endif
+}
+
+#ifdef _WIN32
+constexpr char kHostNameEnvVar[] = "COMPUTERNAME";
+constexpr char kUserNameEnvVar[] = "USERNAME";
+#else
+constexpr char kHostNameEnvVar[] = "HOSTNAME";
+constexpr char kUserNameEnvVar[] = "LOGNAME";
+#endif
+
+std::string GetHostNameUTF8() {
+    const auto hostName = GetEnvironmentVariable(kHostNameEnvVar);
+    if (hostName && !hostName->empty()) {
+        return *hostName;
+    }
+
+#ifdef _WIN32
+    wchar_t wbuf[MAX_COMPUTERNAME_LENGTH + 1];
+    DWORD size = sizeof(wbuf);
+    if (!GetComputerNameW(wbuf, &size) || size == 0) {
+        return "";
+    }
+
+    std::string name;
+    if (!android::base::WideToUTF8(wbuf, &name)) {
+        return "";
+    }
+
+    return name;
+#else   // !_WIN32
+    char buf[256];
+    return (gethostname(buf, sizeof(buf)) == -1) ? "" : buf;
+#endif  // _WIN32
+}
+
+std::string GetLoginNameUTF8() {
+    const auto userName = GetEnvironmentVariable(kUserNameEnvVar);
+    if (userName && !userName->empty()) {
+        return *userName;
+    }
+
+#ifdef _WIN32
+    wchar_t wbuf[UNLEN + 1];
+    DWORD size = sizeof(wbuf);
+    if (!GetUserNameW(wbuf, &size) || size == 0) {
+        return "";
+    }
+
+    std::string login;
+    if (!android::base::WideToUTF8(wbuf, &login)) {
+        return "";
+    }
+
+    return login;
+#else   // !_WIN32
+    const char* login = getlogin();
+    return login ? login : "";
+#endif  // _WIN32
+}
+
+}  // namespace sysdeps
+}  // namespace adb

adb/sysdeps/env.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <optional>
+#include <string>
+
+namespace adb {
+namespace sysdeps {
+
+// Attempts to retrieve the environment variable value for |var|. Returns std::nullopt
+// if unset.
+std::optional<std::string> GetEnvironmentVariableUTF8(std::string_view var);
+
+// Gets the host name of the system. Returns empty string on failure.
+std::string GetHostNameUTF8();
+// Gets the current login user. Returns empty string on failure.
+std::string GetLoginNameUTF8();
+
+}  // namespace sysdeps
+}  // namespace adb

adb/sysdeps_win32.cpp

@@ -1010,55 +1010,6 @@ int adb_register_socket(SOCKET s) {
     return _fh_to_int(f);
 }
 
-static bool isBlankStr(const char* str) {
-    for (; *str != '\0'; ++str) {
-        if (!isblank(*str)) {
-            return false;
-        }
-    }
-    return true;
-}
-
-int adb_gethostname(char* name, size_t len) {
-    const char* computerName = adb_getenv("COMPUTERNAME");
-    if (computerName && !isBlankStr(computerName)) {
-        strncpy(name, computerName, len);
-        name[len - 1] = '\0';
-        return 0;
-    }
-
-    wchar_t buffer[MAX_COMPUTERNAME_LENGTH + 1];
-    DWORD size = sizeof(buffer);
-    if (!GetComputerNameW(buffer, &size)) {
-        return -1;
-    }
-    std::string name_utf8;
-    if (!android::base::WideToUTF8(buffer, &name_utf8)) {
-        return -1;
-    }
-
-    strncpy(name, name_utf8.c_str(), len);
-    name[len - 1] = '\0';
-    return 0;
-}
-
-int adb_getlogin_r(char* buf, size_t bufsize) {
-    wchar_t buffer[UNLEN + 1];
-    DWORD len = sizeof(buffer);
-    if (!GetUserNameW(buffer, &len)) {
-        return -1;
-    }
-
-    std::string login;
-    if (!android::base::WideToUTF8(buffer, &login)) {
-        return -1;
-    }
-
-    strncpy(buf, login.c_str(), bufsize);
-    buf[bufsize - 1] = '\0';
-    return 0;
-}
-
 #undef accept
 int adb_socket_accept(borrowed_fd serverfd, struct sockaddr* addr, socklen_t* addrlen) {
     FH serverfh = _fh_from_int(serverfd, __func__);