Detecting and fixing stringprintf.h format bugs

base/strings/stringprintf.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_STRINGS_STRINGPRINTF_H_
 #define BASE_STRINGS_STRINGPRINTF_H_
 
 #include <stdarg.h>   // va_list
 
 #include <string>
 
 #include "base/base_export.h"
 #include "base/compiler_specific.h"
+#include "build/build_config.h"
+
+#ifdef COMPILER_MSVC
+// For _Printf_format_string_.
+#include <sal.h>
+#else
+// For nacl builds when sal.h is not available.
+#define _Printf_format_string_
+#endif
 
 namespace base {
 
 // Return a C++ string given printf-like input.
-BASE_EXPORT std::string StringPrintf(const char* format, ...)
+BASE_EXPORT std::string StringPrintf(_Printf_format_string_ const char* format,
+                                     ...)
     PRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
 #if defined(OS_WIN)
-BASE_EXPORT std::wstring StringPrintf(const wchar_t* format, ...)
-    WPRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
+BASE_EXPORT std::wstring StringPrintf(
+    _Printf_format_string_ const wchar_t* format,
+    ...) WPRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
 #endif
 
 // Return a C++ string given vprintf-like input.
 BASE_EXPORT std::string StringPrintV(const char* format, va_list ap)
     PRINTF_FORMAT(1, 0) WARN_UNUSED_RESULT;
 
 // Store result into a supplied string and return it.
-BASE_EXPORT const std::string& SStringPrintf(std::string* dst,
-                                             const char* format, ...)
-    PRINTF_FORMAT(2, 3);
+BASE_EXPORT const std::string& SStringPrintf(
+    std::string* dst,
+    _Printf_format_string_ const char* format,
+    ...) PRINTF_FORMAT(2, 3);
 #if defined(OS_WIN)
-BASE_EXPORT const std::wstring& SStringPrintf(std::wstring* dst,
-                                              const wchar_t* format, ...)
-    WPRINTF_FORMAT(2, 3);
+BASE_EXPORT const std::wstring& SStringPrintf(
+    std::wstring* dst,
+    _Printf_format_string_ const wchar_t* format,
+    ...) WPRINTF_FORMAT(2, 3);
 #endif
 
 // Append result to a supplied string.
-BASE_EXPORT void StringAppendF(std::string* dst, const char* format, ...)
-    PRINTF_FORMAT(2, 3);
+BASE_EXPORT void StringAppendF(std::string* dst,
+                               _Printf_format_string_ const char* format,
+                               ...) PRINTF_FORMAT(2, 3);
 #if defined(OS_WIN)
-BASE_EXPORT void StringAppendF(std::wstring* dst, const wchar_t* format, ...)
-    WPRINTF_FORMAT(2, 3);
+BASE_EXPORT void StringAppendF(std::wstring* dst,
+                               _Printf_format_string_ const wchar_t* format,
+                               ...) WPRINTF_FORMAT(2, 3);
 #endif
 
 // Lower-level routine that takes a va_list and appends to a specified
 // string.  All other routines are just convenience wrappers around it.
 BASE_EXPORT void StringAppendV(std::string* dst, const char* format, va_list ap)
     PRINTF_FORMAT(2, 0);
 #if defined(OS_WIN)
 BASE_EXPORT void StringAppendV(std::wstring* dst,
                                const wchar_t* format, va_list ap)
     WPRINTF_FORMAT(2, 0);
 #endif
 
 }  // namespace base
 
 #endif  // BASE_STRINGS_STRINGPRINTF_H_