Hash :
56aee5d6
Author :
Date :
2021-12-10T12:32:58
Reland "system_utils: Add memory protection functionality." This is a reland of b1c703e5f5e44514e8db958a5fb39ff16e514fd8 that was reverted in 663831aa676c59829cc3d822340812f016bf77f6. Skip PageFaultHandlerProtect and PageFaultHandlerDefaultHandler on macOS and Fuchsia. Original change's description: > Reland "system_utils: Add memory protection functionality." > > This is a reland of ab75a90ff4ecb9d99b5c72bde92222b07c285401 > that was reverted in b007e667a8f94b47788a5ba0b2e61c9ac2d1285f. > > Implement PageFaultHandler and memory protection functions. > Uses mprotect and sigaction on POSIX and equivalent Win API functions on > win32. > > Add tests to system_utils_unittests. > > Add stubs for winuwp. > > Replace ASSERT with ASSERT_TRUE in the PageFaultHandlerDefaultHandler > test to make it succeed on release builds, as the code was optimized > out. Furthermore the test did not correctly remove protection from the > whole area it protected, which caused a hang after deinitialization on > some build configurations, since the custom page fault handler was also > still in place. The test now correclty removes protection from the whole > area and sets back the original page fault handler. > > Test: angle_unittests --gtest_filter="SystemUtils.PageFaultHandler*" > Bug: angleproject:5857 > Change-Id: Ibb0acfefd9a09c3360c04c812a2a8346b951e1da > Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3322992 > Reviewed-by: Jamie Madill <jmadill@chromium.org> > Commit-Queue: Lubosz Sarnecki <lubosz.sarnecki@collabora.com> Test: angle_unittests --gtest_filter="SystemUtils.PageFaultHandler*" Bug: angleproject:5857 Change-Id: Ifaa966a7c569aa9ff0112897a02fa8f873cd52dd Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3329610 Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Lubosz Sarnecki <lubosz.sarnecki@collabora.com>
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//
// Copyright 2018 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// system_utils.cpp: Implementation of common functions
#include "common/system_utils.h"
#include <stdlib.h>
#if defined(ANGLE_PLATFORM_ANDROID)
# include <sys/system_properties.h>
#endif
namespace angle
{
std::string GetExecutableName()
{
#if defined(ANGLE_PLATFORM_ANDROID) && __ANDROID_API__ >= 21
// Support for "getprogname" function in bionic was introduced in L (API level 21)
const char *executableName = getprogname();
return (executableName) ? std::string(executableName) : "ANGLE";
#else
std::string executableName = GetExecutablePath();
size_t lastPathSepLoc = executableName.find_last_of(GetPathSeparator());
return (lastPathSepLoc > 0 ? executableName.substr(lastPathSepLoc + 1, executableName.length())
: "ANGLE");
#endif // ANGLE_PLATFORM_ANDROID
}
// On Android return value cached in the process environment, if none, call
// GetEnvironmentVarOrUnCachedAndroidProperty if not in environment.
std::string GetEnvironmentVarOrAndroidProperty(const char *variableName, const char *propertyName)
{
#if defined(ANGLE_PLATFORM_ANDROID) && __ANDROID_API__ >= 21
// Can't use GetEnvironmentVar here because that won't allow us to distinguish between the
// environment being set to an empty string vs. not set at all.
const char *variableValue = getenv(variableName);
if (variableValue != nullptr)
{
std::string value(variableValue);
return value;
}
#endif
return GetEnvironmentVarOrUnCachedAndroidProperty(variableName, propertyName);
}
// Call out to 'getprop' on a shell to get an Android property. If the value was set, set an
// environment variable with that value. Return the value of the environment variable.
std::string GetEnvironmentVarOrUnCachedAndroidProperty(const char *variableName,
const char *propertyName)
{
#if defined(ANGLE_PLATFORM_ANDROID) && __ANDROID_API__ >= 26
std::string propertyValue;
const prop_info *propertyInfo = __system_property_find(propertyName);
if (propertyInfo != nullptr)
{
__system_property_read_callback(
propertyInfo,
[](void *cookie, const char *, const char *value, unsigned) {
auto propertyValue = reinterpret_cast<std::string *>(cookie);
*propertyValue = value;
},
&propertyValue);
}
// Set the environment variable with the value.
SetEnvironmentVar(variableName, propertyValue.c_str());
return propertyValue;
#else
// Return the environment variable's value.
return GetEnvironmentVar(variableName);
#endif // ANGLE_PLATFORM_ANDROID
}
bool GetBoolEnvironmentVar(const char *variableName)
{
std::string envVarString = GetEnvironmentVar(variableName);
return (!envVarString.empty() && envVarString == "1");
}
bool PrependPathToEnvironmentVar(const char *variableName, const char *path)
{
std::string oldValue = GetEnvironmentVar(variableName);
const char *newValue = nullptr;
std::string buf;
if (oldValue.empty())
{
newValue = path;
}
else
{
buf = path;
buf += GetPathSeparatorForEnvironmentVar();
buf += oldValue;
newValue = buf.c_str();
}
return SetEnvironmentVar(variableName, newValue);
}
bool IsFullPath(std::string dirName)
{
if (dirName.find(GetRootDirectory()) == 0)
{
return true;
}
return false;
}
std::string ConcatenatePath(std::string first, std::string second)
{
if (first.empty())
{
return second;
}
if (second.empty())
{
return first;
}
if (IsFullPath(second))
{
return second;
}
bool firstRedundantPathSeparator = first.find_last_of(GetPathSeparator()) == first.length() - 1;
bool secondRedundantPathSeparator = second.find(GetPathSeparator()) == 0;
if (firstRedundantPathSeparator && secondRedundantPathSeparator)
{
return first + second.substr(1);
}
else if (firstRedundantPathSeparator || secondRedundantPathSeparator)
{
return first + second;
}
return first + GetPathSeparator() + second;
}
PageFaultHandler::PageFaultHandler(PageFaultCallback callback) : mCallback(callback) {}
PageFaultHandler::~PageFaultHandler() {}
} // namespace angle