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// Copyright (c) 2010 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.
#include "base/debug/debugger.h"
#include <windows.h>
#include <dbghelp.h>
#include "base/basictypes.h"
#include "base/debug_util.h"
#include "base/logging.h"
namespace base {
namespace debug {
namespace {
// Minimalist key reader.
// Note: Does not use the CRT.
bool RegReadString(HKEY root, const wchar_t* subkey,
const wchar_t* value_name, wchar_t* buffer, int* len) {
HKEY key = NULL;
DWORD res = RegOpenKeyEx(root, subkey, 0, KEY_READ, &key);
if (ERROR_SUCCESS != res || key == NULL)
return false;
DWORD type = 0;
DWORD buffer_size = *len * sizeof(wchar_t);
// We don't support REG_EXPAND_SZ.
res = RegQueryValueEx(key, value_name, NULL, &type,
reinterpret_cast<BYTE*>(buffer), &buffer_size);
if (ERROR_SUCCESS == res && buffer_size != 0 && type == REG_SZ) {
// Make sure the buffer is NULL terminated.
buffer[*len - 1] = 0;
*len = lstrlen(buffer);
RegCloseKey(key);
return true;
}
RegCloseKey(key);
return false;
}
// Replaces each "%ld" in input per a value. Not efficient but it works.
// Note: Does not use the CRT.
bool StringReplace(const wchar_t* input, int value, wchar_t* output,
int output_len) {
memset(output, 0, output_len*sizeof(wchar_t));
int input_len = lstrlen(input);
for (int i = 0; i < input_len; ++i) {
int current_output_len = lstrlen(output);
if (input[i] == L'%' && input[i + 1] == L'l' && input[i + 2] == L'd') {
// Make sure we have enough place left.
if ((current_output_len + 12) >= output_len)
return false;
// Cheap _itow().
wsprintf(output+current_output_len, L"%d", value);
i += 2;
} else {
if (current_output_len >= output_len)
return false;
output[current_output_len] = input[i];
}
}
return true;
}
} // namespace
// Note: Does not use the CRT.
bool SpawnDebuggerOnProcess(unsigned process_id) {
wchar_t reg_value[1026];
int len = arraysize(reg_value);
if (RegReadString(HKEY_LOCAL_MACHINE,
L"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\AeDebug",
L"Debugger", reg_value, &len)) {
wchar_t command_line[1026];
if (StringReplace(reg_value, process_id, command_line,
arraysize(command_line))) {
// We don't mind if the debugger is present because it will simply fail
// to attach to this process.
STARTUPINFO startup_info = {0};
startup_info.cb = sizeof(startup_info);
PROCESS_INFORMATION process_info = {0};
if (CreateProcess(NULL, command_line, NULL, NULL, FALSE, 0, NULL, NULL,
&startup_info, &process_info)) {
CloseHandle(process_info.hThread);
WaitForInputIdle(process_info.hProcess, 10000);
CloseHandle(process_info.hProcess);
return true;
}
}
}
return false;
}
bool BeingDebugged() {
return ::IsDebuggerPresent() != 0;
}
void BreakDebugger() {
if (DebugUtil::AreDialogsSuppressed())
_exit(1);
__debugbreak();
}
} // namespace debug
} // namespace base
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