1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "android-base/errors.h"
18 
19 #include <windows.h>
20 
21 #include "android-base/stringprintf.h"
22 #include "android-base/strings.h"
23 #include "android-base/utf8.h"
24 
25 // A Windows error code is a DWORD. It's simpler to use an int error code for
26 // both Unix and Windows if possible, but if this fails we'll need a different
27 // function signature for each.
28 static_assert(sizeof(int) >= sizeof(DWORD),
29               "Windows system error codes are too large to fit in an int.");
30 
31 namespace android {
32 namespace base {
33 
34 static constexpr DWORD kErrorMessageBufferSize = 256;
35 
SystemErrorCodeToString(int int_error_code)36 std::string SystemErrorCodeToString(int int_error_code) {
37   WCHAR msgbuf[kErrorMessageBufferSize];
38   DWORD error_code = int_error_code;
39   DWORD flags = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS;
40   DWORD len = FormatMessageW(flags, nullptr, error_code, 0, msgbuf,
41                              kErrorMessageBufferSize, nullptr);
42   if (len == 0) {
43     return android::base::StringPrintf(
44         "Error %lu while retrieving message for error %lu", GetLastError(),
45         error_code);
46   }
47 
48   // Convert UTF-16 to UTF-8.
49   std::string msg;
50   if (!android::base::WideToUTF8(msgbuf, &msg)) {
51     return android::base::StringPrintf(
52         "Error %lu while converting message for error %lu from UTF-16 to UTF-8",
53         GetLastError(), error_code);
54   }
55 
56   // Messages returned by the system end with line breaks.
57   msg = android::base::Trim(msg);
58 
59   // There are many Windows error messages compared to POSIX, so include the
60   // numeric error code for easier, quicker, accurate identification. Use
61   // decimal instead of hex because there are decimal ranges like 10000-11999
62   // for Winsock.
63   android::base::StringAppendF(&msg, " (%lu)", error_code);
64   return msg;
65 }
66 
67 }  // namespace base
68 }  // namespace android
69