Initial population of CoreRT Runtime files.

1 files changed, 130 insertions, 0 deletions

diff --git a/src/Native/Runtime/RhConfig.h b/src/Native/Runtime/RhConfig.h
new file mode 100644
index 000000000..4045db0b4
--- /dev/null
+++ b/src/Native/Runtime/RhConfig.h
@@ -0,0 +1,130 @@
+//
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license 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 RH_ENVIRONMENT_VARIABLE_CONFIG_ENABLED
+#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:
+        WCHAR Key[CONFIG_KEY_MAXLEN + 1];  //maxlen + null terminator
+        WCHAR 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;
+
+public:
+
+#define DEFINE_VALUE_ACCESSOR(_name)                    \
+    UInt32 Get##_name()                                 \
+    {                                                   \
+        if (m_uiConfigValuesRead & (1 << RCV_##_name))  \
+            return m_uiConfigValues[RCV_##_name];       \
+        UInt32 uiValue = ReadConfigValue(L"RH_" L ## #_name); \
+        m_uiConfigValues[RCV_##_name] = uiValue;        \
+        m_uiConfigValuesRead |= 1 << RCV_##_name;       \
+        return uiValue;                                 \
+    }
+
+
+#ifdef _DEBUG
+#define DEBUG_CONFIG_VALUE(_name) DEFINE_VALUE_ACCESSOR(_name)
+#else
+#define DEBUG_CONFIG_VALUE(_name) 
+#endif
+#define RETAIL_CONFIG_VALUE(_name) DEFINE_VALUE_ACCESSOR(_name)
+#include "RhConfigValues.h"
+#undef DEBUG_CONFIG_VALUE
+#undef RETAIL_CONFIG_VALUE
+
+private:
+
+    UInt32 ReadConfigValue(_In_z_ WCHAR *wszName);
+
+    enum RhConfigValue
+    {
+#define DEBUG_CONFIG_VALUE(_name) RCV_##_name,
+#define RETAIL_CONFIG_VALUE(_name) RCV_##_name,
+#include "RhConfigValues.h"
+#undef DEBUG_CONFIG_VALUE
+#undef RETAIL_CONFIG_VALUE
+        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_ WCHAR* RhConfig::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
+    //cchOuputBuffer is the maximum number of characters to write to outputBuffer
+    UInt32 GetIniVariable(_In_z_ WCHAR* configName, _Out_writes_all_(cchBuff) WCHAR* outputBuffer, _In_ UInt32 cchOuputBuffer);
+
+    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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