1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/security/sandbox/chromium/base/strings/stringprintf.cc Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,186 @@
1.4 +// Copyright 2013 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#include "base/strings/stringprintf.h"
1.9 +
1.10 +#include <errno.h>
1.11 +
1.12 +#include "base/scoped_clear_errno.h"
1.13 +#include "base/strings/string_util.h"
1.14 +#include "base/strings/utf_string_conversions.h"
1.15 +
1.16 +namespace base {
1.17 +
1.18 +namespace {
1.19 +
1.20 +// Overloaded wrappers around vsnprintf and vswprintf. The buf_size parameter
1.21 +// is the size of the buffer. These return the number of characters in the
1.22 +// formatted string excluding the NUL terminator. If the buffer is not
1.23 +// large enough to accommodate the formatted string without truncation, they
1.24 +// return the number of characters that would be in the fully-formatted string
1.25 +// (vsnprintf, and vswprintf on Windows), or -1 (vswprintf on POSIX platforms).
1.26 +inline int vsnprintfT(char* buffer,
1.27 + size_t buf_size,
1.28 + const char* format,
1.29 + va_list argptr) {
1.30 + return base::vsnprintf(buffer, buf_size, format, argptr);
1.31 +}
1.32 +
1.33 +#if !defined(OS_ANDROID)
1.34 +inline int vsnprintfT(wchar_t* buffer,
1.35 + size_t buf_size,
1.36 + const wchar_t* format,
1.37 + va_list argptr) {
1.38 + return base::vswprintf(buffer, buf_size, format, argptr);
1.39 +}
1.40 +#endif
1.41 +
1.42 +// Templatized backend for StringPrintF/StringAppendF. This does not finalize
1.43 +// the va_list, the caller is expected to do that.
1.44 +template <class StringType>
1.45 +static void StringAppendVT(StringType* dst,
1.46 + const typename StringType::value_type* format,
1.47 + va_list ap) {
1.48 + // First try with a small fixed size buffer.
1.49 + // This buffer size should be kept in sync with StringUtilTest.GrowBoundary
1.50 + // and StringUtilTest.StringPrintfBounds.
1.51 + typename StringType::value_type stack_buf[1024];
1.52 +
1.53 + va_list ap_copy;
1.54 + GG_VA_COPY(ap_copy, ap);
1.55 +
1.56 +#if !defined(OS_WIN)
1.57 + ScopedClearErrno clear_errno;
1.58 +#endif
1.59 + int result = vsnprintfT(stack_buf, arraysize(stack_buf), format, ap_copy);
1.60 + va_end(ap_copy);
1.61 +
1.62 + if (result >= 0 && result < static_cast<int>(arraysize(stack_buf))) {
1.63 + // It fit.
1.64 + dst->append(stack_buf, result);
1.65 + return;
1.66 + }
1.67 +
1.68 + // Repeatedly increase buffer size until it fits.
1.69 + int mem_length = arraysize(stack_buf);
1.70 + while (true) {
1.71 + if (result < 0) {
1.72 +#if !defined(OS_WIN)
1.73 + // On Windows, vsnprintfT always returns the number of characters in a
1.74 + // fully-formatted string, so if we reach this point, something else is
1.75 + // wrong and no amount of buffer-doubling is going to fix it.
1.76 + if (errno != 0 && errno != EOVERFLOW)
1.77 +#endif
1.78 + {
1.79 + // If an error other than overflow occurred, it's never going to work.
1.80 + DLOG(WARNING) << "Unable to printf the requested string due to error.";
1.81 + return;
1.82 + }
1.83 + // Try doubling the buffer size.
1.84 + mem_length *= 2;
1.85 + } else {
1.86 + // We need exactly "result + 1" characters.
1.87 + mem_length = result + 1;
1.88 + }
1.89 +
1.90 + if (mem_length > 32 * 1024 * 1024) {
1.91 + // That should be plenty, don't try anything larger. This protects
1.92 + // against huge allocations when using vsnprintfT implementations that
1.93 + // return -1 for reasons other than overflow without setting errno.
1.94 + DLOG(WARNING) << "Unable to printf the requested string due to size.";
1.95 + return;
1.96 + }
1.97 +
1.98 + std::vector<typename StringType::value_type> mem_buf(mem_length);
1.99 +
1.100 + // NOTE: You can only use a va_list once. Since we're in a while loop, we
1.101 + // need to make a new copy each time so we don't use up the original.
1.102 + GG_VA_COPY(ap_copy, ap);
1.103 + result = vsnprintfT(&mem_buf[0], mem_length, format, ap_copy);
1.104 + va_end(ap_copy);
1.105 +
1.106 + if ((result >= 0) && (result < mem_length)) {
1.107 + // It fit.
1.108 + dst->append(&mem_buf[0], result);
1.109 + return;
1.110 + }
1.111 + }
1.112 +}
1.113 +
1.114 +} // namespace
1.115 +
1.116 +std::string StringPrintf(const char* format, ...) {
1.117 + va_list ap;
1.118 + va_start(ap, format);
1.119 + std::string result;
1.120 + StringAppendV(&result, format, ap);
1.121 + va_end(ap);
1.122 + return result;
1.123 +}
1.124 +
1.125 +#if !defined(OS_ANDROID)
1.126 +std::wstring StringPrintf(const wchar_t* format, ...) {
1.127 + va_list ap;
1.128 + va_start(ap, format);
1.129 + std::wstring result;
1.130 + StringAppendV(&result, format, ap);
1.131 + va_end(ap);
1.132 + return result;
1.133 +}
1.134 +#endif
1.135 +
1.136 +std::string StringPrintV(const char* format, va_list ap) {
1.137 + std::string result;
1.138 + StringAppendV(&result, format, ap);
1.139 + return result;
1.140 +}
1.141 +
1.142 +const std::string& SStringPrintf(std::string* dst, const char* format, ...) {
1.143 + va_list ap;
1.144 + va_start(ap, format);
1.145 + dst->clear();
1.146 + StringAppendV(dst, format, ap);
1.147 + va_end(ap);
1.148 + return *dst;
1.149 +}
1.150 +
1.151 +#if !defined(OS_ANDROID)
1.152 +const std::wstring& SStringPrintf(std::wstring* dst,
1.153 + const wchar_t* format, ...) {
1.154 + va_list ap;
1.155 + va_start(ap, format);
1.156 + dst->clear();
1.157 + StringAppendV(dst, format, ap);
1.158 + va_end(ap);
1.159 + return *dst;
1.160 +}
1.161 +#endif
1.162 +
1.163 +void StringAppendF(std::string* dst, const char* format, ...) {
1.164 + va_list ap;
1.165 + va_start(ap, format);
1.166 + StringAppendV(dst, format, ap);
1.167 + va_end(ap);
1.168 +}
1.169 +
1.170 +#if !defined(OS_ANDROID)
1.171 +void StringAppendF(std::wstring* dst, const wchar_t* format, ...) {
1.172 + va_list ap;
1.173 + va_start(ap, format);
1.174 + StringAppendV(dst, format, ap);
1.175 + va_end(ap);
1.176 +}
1.177 +#endif
1.178 +
1.179 +void StringAppendV(std::string* dst, const char* format, va_list ap) {
1.180 + StringAppendVT(dst, format, ap);
1.181 +}
1.182 +
1.183 +#if !defined(OS_ANDROID)
1.184 +void StringAppendV(std::wstring* dst, const wchar_t* format, va_list ap) {
1.185 + StringAppendVT(dst, format, ap);
1.186 +}
1.187 +#endif
1.188 +
1.189 +} // namespace base
