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// Copyright 2008 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#include "Common/MemArena.h"
#include <cerrno>
#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <string>
#include <fmt/format.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include "Common/Assert.h"
#include "Common/CommonFuncs.h"
#include "Common/CommonTypes.h"
#include "Common/Logging/Log.h"
#include "Common/MsgHandler.h"
namespace Common
{
MemArena::MemArena() = default;
MemArena::~MemArena() = default;
void MemArena::GrabSHMSegment(size_t size, std::string_view base_name)
{
const std::string file_name = fmt::format("/{}.{}", base_name, getpid());
m_shm_fd = shm_open(file_name.c_str(), O_RDWR | O_CREAT | O_EXCL, 0600);
if (m_shm_fd == -1)
{
ERROR_LOG_FMT(MEMMAP, "shm_open failed: {}", strerror(errno));
return;
}
shm_unlink(file_name.c_str());
if (ftruncate(m_shm_fd, size) < 0)
ERROR_LOG_FMT(MEMMAP, "Failed to allocate low memory space");
}
void MemArena::ReleaseSHMSegment()
{
close(m_shm_fd);
}
void* MemArena::CreateView(s64 offset, size_t size)
{
void* retval = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, m_shm_fd, offset);
if (retval == MAP_FAILED)
{
NOTICE_LOG_FMT(MEMMAP, "mmap failed");
return nullptr;
}
else
{
return retval;
}
}
void MemArena::ReleaseView(void* view, size_t size)
{
munmap(view, size);
}
u8* MemArena::ReserveMemoryRegion(size_t memory_size)
{
const int flags = MAP_ANON | MAP_PRIVATE;
void* base = mmap(nullptr, memory_size, PROT_NONE, flags, -1, 0);
if (base == MAP_FAILED)
{
PanicAlertFmt("Failed to map enough memory space: {}", LastStrerrorString());
return nullptr;
}
m_reserved_region = base;
m_reserved_region_size = memory_size;
return static_cast<u8*>(base);
}
void MemArena::ReleaseMemoryRegion()
{
if (m_reserved_region)
{
munmap(m_reserved_region, m_reserved_region_size);
m_reserved_region = nullptr;
}
}
void* MemArena::MapInMemoryRegion(s64 offset, size_t size, void* base, bool writeable)
{
int prot = PROT_READ;
if (writeable)
prot |= PROT_WRITE;
void* retval = mmap(base, size, prot, MAP_SHARED | MAP_FIXED, m_shm_fd, offset);
if (retval == MAP_FAILED)
{
NOTICE_LOG_FMT(MEMMAP, "mmap failed");
return nullptr;
}
else
{
return retval;
}
}
bool MemArena::ChangeMappingProtection(void* view, size_t size, bool writeable)
{
int prot = PROT_READ;
if (writeable)
prot |= PROT_WRITE;
int retval = mprotect(view, size, prot);
if (retval != 0)
NOTICE_LOG_FMT(MEMMAP, "mprotect failed");
return retval == 0;
}
void MemArena::UnmapFromMemoryRegion(void* view, size_t size)
{
void* retval = mmap(view, size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
if (retval == MAP_FAILED)
NOTICE_LOG_FMT(MEMMAP, "mmap failed");
}
size_t MemArena::GetPageSize() const
{
return sysconf(_SC_PAGESIZE);
}
LazyMemoryRegion::LazyMemoryRegion() = default;
LazyMemoryRegion::~LazyMemoryRegion()
{
Release();
}
#if !defined MAP_NORESERVE && (defined __FreeBSD__ || defined __OpenBSD__ || defined __NetBSD__)
// BSD does not implement MAP_NORESERVE, so define the flag to nothing.
// See https://reviews.freebsd.org/rS273250
#define MAP_NORESERVE 0
#endif
void* LazyMemoryRegion::Create(size_t size)
{
ASSERT(!m_memory);
if (size == 0)
return nullptr;
void* memory = mmap(nullptr, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
if (memory == MAP_FAILED)
{
NOTICE_LOG_FMT(MEMMAP, "Memory allocation of {} bytes failed.", size);
return nullptr;
}
m_memory = memory;
m_size = size;
return memory;
}
void LazyMemoryRegion::Clear()
{
ASSERT(m_memory);
void* new_memory = mmap(m_memory, m_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE | MAP_FIXED, -1, 0);
ASSERT(new_memory == m_memory);
}
void LazyMemoryRegion::Release()
{
if (m_memory)
{
munmap(m_memory, m_size);
m_memory = nullptr;
m_size = 0;
}
}
} // namespace Common
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