From 9c349273f5d8f4aa836dda86d6e936c6b034928a Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Wed, 4 Nov 2020 12:24:46 +0100
Subject: api: concatenate function name at runtime

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 api/logger.c     | 23 ++++++++++++++++++++---
 api/logger.h     | 22 ++++++++--------------
 api/rundll32_i.c |  2 +-
 3 files changed, 29 insertions(+), 18 deletions(-)

(limited to 'api')

diff --git a/api/logger.c b/api/logger.c
index c954f6c..fc43706 100644
--- a/api/logger.c
+++ b/api/logger.c
@@ -25,7 +25,24 @@ WintunSetLogger(_In_ WINTUN_LOGGER_CALLBACK_FUNC NewLogger)
 }
 
 _Post_equals_last_error_ DWORD
-LoggerError(_In_z_ const WCHAR *Prefix, _In_ DWORD Error)
+LoggerLog(_In_ WINTUN_LOGGER_LEVEL Level, _In_z_ const WCHAR *Function, _In_z_ const WCHAR *LogLine)
+{
+    DWORD LastError = GetLastError();
+    if (Function)
+    {
+        WCHAR Combined[0x400];
+        if (_snwprintf_s(Combined, _countof(Combined), _TRUNCATE, L"%s: %s", Function, LogLine) == -1)
+            return LastError;
+        Logger(Level, Combined);
+    }
+    else
+        Logger(Level, LogLine);
+    SetLastError(LastError);
+    return LastError;
+}
+
+_Post_equals_last_error_ DWORD
+LoggerError(_In_z_ const WCHAR *Function, _In_z_ const WCHAR *Prefix, _In_ DWORD Error)
 {
     WCHAR *SystemMessage = NULL, *FormattedMessage = NULL;
     FormatMessageW(
@@ -39,12 +56,12 @@ LoggerError(_In_z_ const WCHAR *Prefix, _In_ DWORD Error)
     FormatMessageW(
         FORMAT_MESSAGE_FROM_STRING | FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_ARGUMENT_ARRAY |
             FORMAT_MESSAGE_MAX_WIDTH_MASK,
-        SystemMessage ? L"%1: %3(Code 0x%2!08X!)" : L"%1: Code 0x%2!08X!",
+        SystemMessage ? L"%4: %1: %3(Code 0x%2!08X!)" : L"%1: Code 0x%2!08X!",
         0,
         0,
         (void *)&FormattedMessage,
         0,
-        (va_list *)(DWORD_PTR[]){ (DWORD_PTR)Prefix, (DWORD_PTR)Error, (DWORD_PTR)SystemMessage });
+        (va_list *)(DWORD_PTR[]){ (DWORD_PTR)Prefix, (DWORD_PTR)Error, (DWORD_PTR)SystemMessage, (DWORD_PTR)Function });
     if (FormattedMessage)
         Logger(WINTUN_LOG_ERR, FormattedMessage);
     LocalFree(FormattedMessage);
diff --git a/api/logger.h b/api/logger.h
index 0affdc3..b0458c5 100644
--- a/api/logger.h
+++ b/api/logger.h
@@ -16,29 +16,23 @@ extern WINTUN_LOGGER_CALLBACK_FUNC Logger;
 void WINAPI
 WintunSetLogger(_In_ WINTUN_LOGGER_CALLBACK_FUNC NewLogger);
 
-static inline _Post_equals_last_error_ DWORD
-LoggerLog(_In_ WINTUN_LOGGER_LEVEL Level, _In_z_ const WCHAR *LogLine)
-{
-    DWORD LastError = GetLastError();
-    Logger(Level, LogLine);
-    SetLastError(LastError);
-    return LastError;
-}
+_Post_equals_last_error_ DWORD
+LoggerLog(_In_ WINTUN_LOGGER_LEVEL Level, _In_z_ const WCHAR *Function, _In_z_ const WCHAR *LogLine);
 
 _Post_equals_last_error_ DWORD
-LoggerError(_In_z_ const WCHAR *Prefix, _In_ DWORD Error);
+LoggerError(_In_z_ const WCHAR *Function, _In_z_ const WCHAR *Prefix, _In_ DWORD Error);
 
 static inline _Post_equals_last_error_ DWORD
-LoggerLastError(_In_z_ const WCHAR *Prefix)
+LoggerLastError(_In_z_ const WCHAR *Function, _In_z_ const WCHAR *Prefix)
 {
     DWORD LastError = GetLastError();
-    LoggerError(Prefix, LastError);
+    LoggerError(Prefix, Function, LastError);
     SetLastError(LastError);
     return LastError;
 }
 
 #define __L(x) L##x
 #define _L(x) __L(x)
-#define LOG(lvl, msg) (LoggerLog((lvl), _L(__FUNCTION__) L": " msg))
-#define LOG_ERROR(msg, err) (LoggerError(_L(__FUNCTION__) L": " msg, (err)))
-#define LOG_LAST_ERROR(msg) (LoggerLastError(_L(__FUNCTION__) L": " msg))
+#define LOG(lvl, msg) (LoggerLog((lvl), _L(__FUNCTION__), msg))
+#define LOG_ERROR(msg, err) (LoggerError(_L(__FUNCTION__), msg, (err)))
+#define LOG_LAST_ERROR(msg) (LoggerLastError(_L(__FUNCTION__), msg))
diff --git a/api/rundll32_i.c b/api/rundll32_i.c
index ca4a504..5f9de48 100644
--- a/api/rundll32_i.c
+++ b/api/rundll32_i.c
@@ -72,7 +72,7 @@ ProcessStderr(_In_ HANDLE Stderr)
             else if (State == OnMsg && c == L'\n')
             {
                 Msg[Count] = 0;
-                LoggerLog(Level, Msg);
+                LoggerLog(Level, NULL, Msg);
                 State = OnNone;
                 Count = 0;
             }
-- 
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