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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//
// Provides simple configuration support through environment variables. Each variable is lazily inspected on
// first query and the resulting value cached for future use. To keep things simple we support reading only
// 32-bit hex quantities and a zero value is considered equivalent to the environment variable not being
// defined. We can get more sophisticated if needs be, but the hope is that very few configuration values are
// exposed in this manner.
//
// Values can also be configured through an rhconfig.ini file. The file must be and ASCII text file, must be
// placed next to the executing assembly, and be named rhconfig.ini. The file consists of one config entry per line
// in the format: <Key>=<Value>
// example:
// RH_HeapVerify=1
// RH_BreakOnAssert=1
//
#ifndef DACCESS_COMPILE
#if defined(_DEBUG) || !defined(APP_LOCAL_RUNTIME)
#define FEATURE_ENVIRONMENT_VARIABLE_CONFIG
#endif
class RhConfig
{
#define CONFIG_INI_FILENAME L"rhconfig.ini"
#define CONFIG_INI_NOT_AVAIL (void*)0x1 //signal for ini file failed to load
#define CONFIG_KEY_MAXLEN 50 //arbitrary max length of config keys increase if needed
#define CONFIG_VAL_MAXLEN 8 //32 bit uint in hex
private:
struct ConfigPair
{
public:
TCHAR Key[CONFIG_KEY_MAXLEN + 1]; //maxlen + null terminator
TCHAR Value[CONFIG_VAL_MAXLEN + 1]; //maxlen + null terminator
};
//g_iniSettings is a buffer of ConfigPair structs which when initialized is of length RCV_Count
//the first N settings which are set in rhconfig.ini will be initialized and the remainder with have
//empty string "\0" as a Key and Value
//
//if the buffer has not been initialized (ie the ini file has not been read) the value will be NULL
//if we already attempted to initialize the file and could not find or read the contents the
//value will be CONFIG_INI_NOT_AVAIL to distinguish from the unitialized buffer.
//
//NOTE: g_iniSettings is only set in ReadConfigIni and must be set atomically only once
// using PalInterlockedCompareExchangePointer to avoid races when initializing
private:
void* volatile g_iniSettings = NULL;
#ifdef FEATURE_EMBEDDED_CONFIG
// g_embeddedSettings works similarly to g_iniSettings, except the source of the data
// is a data blob generated by the compiler and embedded into the executable.
void* volatile g_embeddedSettings = NULL;
#endif // FEATURE_EMBEDDED_CONFIG
public:
#define DEFINE_VALUE_ACCESSOR(_name, defaultVal) \
UInt32 Get##_name() \
{ \
if (m_uiConfigValuesRead & (1 << RCV_##_name)) \
return m_uiConfigValues[RCV_##_name]; \
UInt32 uiValue = ReadConfigValue(_T("RH_") _T(#_name), defaultVal); \
m_uiConfigValues[RCV_##_name] = uiValue; \
m_uiConfigValuesRead |= 1 << RCV_##_name; \
return uiValue; \
}
#ifdef _DEBUG
#define DEBUG_CONFIG_VALUE(_name) DEFINE_VALUE_ACCESSOR(_name, 0)
#define DEBUG_CONFIG_VALUE_WITH_DEFAULT(_name, defaultVal) DEFINE_VALUE_ACCESSOR(_name, defaultVal)
#else
#define DEBUG_CONFIG_VALUE(_name)
#define DEBUG_CONFIG_VALUE_WITH_DEFAULT(_name, defaultVal)
#endif
#define RETAIL_CONFIG_VALUE(_name) DEFINE_VALUE_ACCESSOR(_name, 0)
#define RETAIL_CONFIG_VALUE_WITH_DEFAULT(_name, defaultVal) DEFINE_VALUE_ACCESSOR(_name, defaultVal)
#include "RhConfigValues.h"
#undef DEBUG_CONFIG_VALUE
#undef RETAIL_CONFIG_VALUE
#undef DEBUG_CONFIG_VALUE_WITH_DEFAULT
#undef RETAIL_CONFIG_VALUE_WITH_DEFAULT
private:
UInt32 ReadConfigValue(_In_z_ const TCHAR *wszName, UInt32 uiDefault);
enum RhConfigValue
{
#define DEBUG_CONFIG_VALUE(_name) RCV_##_name,
#define RETAIL_CONFIG_VALUE(_name) RCV_##_name,
#define DEBUG_CONFIG_VALUE_WITH_DEFAULT(_name, defaultVal) RCV_##_name,
#define RETAIL_CONFIG_VALUE_WITH_DEFAULT(_name, defaultVal) RCV_##_name,
#include "RhConfigValues.h"
#undef DEBUG_CONFIG_VALUE
#undef RETAIL_CONFIG_VALUE
#undef DEBUG_CONFIG_VALUE_WITH_DEFAULT
#undef RETAIL_CONFIG_VALUE_WITH_DEFAULT
RCV_Count
};
//accomidate for the maximum number of config values plus sizable buffer for whitespace 2K
#define CONFIG_FILE_MAXLEN RCV_Count * sizeof(ConfigPair) + 2000
private:
_Ret_maybenull_z_ TCHAR* GetConfigPath();
//Parses one line of rhconfig.ini and populates values in the passed in configPair
//returns: true if the parsing was successful, false if the parsing failed.
//NOTE: if the method fails configPair is left in an unitialized state
bool ParseConfigLine(_Out_ ConfigPair* configPair, _In_z_ const char * line);
//reads the configuration values from rhconfig.ini and updates g_iniSettings
//if the file is read succesfully and g_iniSettings will be set to a valid ConfigPair[] of length RCV_Count.
//if the file does not exist or reading the file fails, g_iniSettings is set to CONFIG_INI_NOT_AVAIL
//NOTE: all return paths must set g_iniSettings
void ReadConfigIni();
//reads a config value from rhconfig.ini into outputBuffer buffer returning the length of the value.
//lazily reads the file so if the file is not yet read, it will read it on first called
//if the file is not avaliable, or unreadable zero will always be returned
//cchOutputBuffer is the maximum number of characters to write to outputBuffer
UInt32 GetIniVariable(_In_z_ const TCHAR* configName, _Out_writes_all_(cchOutputBuffer) TCHAR* outputBuffer, _In_ UInt32 cchOutputBuffer);
#ifdef FEATURE_EMBEDDED_CONFIG
void ReadEmbeddedSettings();
UInt32 GetEmbeddedVariable(_In_z_ const TCHAR* configName, _Out_writes_all_(cchOutputBuffer) TCHAR* outputBuffer, _In_ UInt32 cchOutputBuffer);
#endif // FEATURE_EMBEDDED_CONFIG
UInt32 GetConfigVariable(_In_z_ const TCHAR* configName, const ConfigPair* configPairs, _Out_writes_all_(cchOutputBuffer) TCHAR* outputBuffer, _In_ UInt32 cchOutputBuffer);
static bool priv_isspace(char c)
{
return (c == ' ') || (c == '\t') || (c == '\n') || (c == '\r');
}
UInt32 m_uiConfigValuesRead;
UInt32 m_uiConfigValues[RCV_Count];
};
extern RhConfig * g_pRhConfig;
#endif //!DACCESS_COMPILE
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