From 728d6762cd95394f2541d4a3f3e7fdd17ecd8f2a Mon Sep 17 00:00:00 2001
From: Simon Rozman <simon@rozman.si>
Date: Tue, 2 Feb 2021 13:12:45 +0100
Subject: api: upgrade logging

Log runtime information to quickly check whether the values are sane
when analyzing error logs sent in by users.

Signed-off-by: Simon Rozman <simon@rozman.si>
---
 api/logger.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 70 insertions(+), 5 deletions(-)

(limited to 'api/logger.c')

diff --git a/api/logger.c b/api/logger.c
index 0ebdd6e..7907437 100644
--- a/api/logger.c
+++ b/api/logger.c
@@ -4,7 +4,9 @@
  */
 
 #include "logger.h"
+#include "ntdll.h"
 #include <Windows.h>
+#include <winternl.h>
 #include <wchar.h>
 
 static BOOL CALLBACK
@@ -25,6 +27,13 @@ WintunSetLogger(_In_ WINTUN_LOGGER_CALLBACK NewLogger)
     Logger = NewLogger;
 }
 
+static VOID
+StrTruncate(_Inout_count_(StrChars) WCHAR *Str, _In_ SIZE_T StrChars)
+{
+    Str[StrChars - 2] = L'\u2026'; /* Horizontal Ellipsis */
+    Str[StrChars - 1] = 0;
+}
+
 _Post_equals_last_error_ DWORD
 LoggerLog(_In_ WINTUN_LOGGER_LEVEL Level, _In_z_ const WCHAR *Function, _In_z_ const WCHAR *LogLine)
 {
@@ -33,10 +42,7 @@ LoggerLog(_In_ WINTUN_LOGGER_LEVEL Level, _In_z_ const WCHAR *Function, _In_z_ c
     {
         WCHAR Combined[0x400];
         if (_snwprintf_s(Combined, _countof(Combined), _TRUNCATE, L"%s: %s", Function, LogLine) == -1)
-        {
-            Combined[_countof(Combined) - 2] = L'\u2026'; /* Horizontal Ellipsis */
-            Combined[_countof(Combined) - 1] = 0;
-        }
+            StrTruncate(Combined, _countof(Combined));
         Logger(Level, Combined);
     }
     else
@@ -46,7 +52,26 @@ LoggerLog(_In_ WINTUN_LOGGER_LEVEL Level, _In_z_ const WCHAR *Function, _In_z_ c
 }
 
 _Post_equals_last_error_ DWORD
-LoggerError(_In_z_ const WCHAR *Function, _In_z_ const WCHAR *Prefix, _In_ DWORD Error)
+LoggerLogV(
+    _In_ WINTUN_LOGGER_LEVEL Level,
+    _In_z_ const WCHAR *Function,
+    _In_z_ _Printf_format_string_ const WCHAR *Format,
+    _In_ va_list Args)
+{
+    DWORD LastError = GetLastError();
+    WCHAR LogLine[0x400];
+    if (_vsnwprintf_s(LogLine, _countof(LogLine), _TRUNCATE, Format, Args) == -1)
+        StrTruncate(LogLine, _countof(LogLine));
+    if (Function)
+        LoggerLog(Level, Function, LogLine);
+    else
+        Logger(Level, LogLine);
+    SetLastError(LastError);
+    return LastError;
+}
+
+_Post_equals_last_error_ DWORD
+LoggerError(_In_ DWORD Error, _In_z_ const WCHAR *Function, _In_z_ const WCHAR *Prefix)
 {
     WCHAR *SystemMessage = NULL, *FormattedMessage = NULL;
     FormatMessageW(
@@ -72,3 +97,43 @@ LoggerError(_In_z_ const WCHAR *Function, _In_z_ const WCHAR *Prefix, _In_ DWORD
     LocalFree(SystemMessage);
     return Error;
 }
+
+_Post_equals_last_error_ DWORD
+LoggerErrorV(
+    _In_ DWORD Error,
+    _In_z_ const WCHAR *Function,
+    _In_z_ _Printf_format_string_ const WCHAR *Format,
+    _In_ va_list Args)
+{
+    WCHAR Prefix[0x400];
+    if (_vsnwprintf_s(Prefix, _countof(Prefix), _TRUNCATE, Format, Args) == -1)
+        StrTruncate(Prefix, _countof(Prefix));
+    return LoggerError(Error, Function, Prefix);
+}
+
+VOID
+LoggerGetRegistryKeyPath(_In_ HKEY Key, _Out_cap_c_(MAX_REG_PATH) WCHAR *Path)
+{
+    DWORD LastError = GetLastError();
+    if (Key == NULL)
+    {
+        wcscpy_s(Path, MAX_REG_PATH, L"<null>");
+        goto out;
+    }
+    if (_snwprintf_s(Path, MAX_REG_PATH, _TRUNCATE, L"0x%p", Key) == -1)
+        StrTruncate(Path, MAX_REG_PATH);
+    union
+    {
+        KEY_NAME_INFORMATION KeyNameInfo;
+        WCHAR Data[offsetof(KEY_NAME_INFORMATION, Name) + MAX_REG_PATH];
+    } Buffer;
+    DWORD Size;
+    if (!NT_SUCCESS(NtQueryKey(Key, 3, &Buffer, sizeof(Buffer), &Size)) ||
+        Size < offsetof(KEY_NAME_INFORMATION, Name) || Buffer.KeyNameInfo.NameLength >= MAX_REG_PATH * sizeof(WCHAR))
+        goto out;
+    Buffer.KeyNameInfo.NameLength /= sizeof(WCHAR);
+    wmemcpy_s(Path, MAX_REG_PATH, Buffer.KeyNameInfo.Name, Buffer.KeyNameInfo.NameLength);
+    Path[Buffer.KeyNameInfo.NameLength] = L'\0';
+out:
+    SetLastError(LastError);
+}
-- 
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