From a72b98ed5a357bb380d81f07f3f36946aa729bb2 Mon Sep 17 00:00:00 2001
From: Mark Rowe <mark@vector35.com>
Date: Mon, 23 Feb 2026 23:26:27 -0800
Subject: [DSC] Simplify file mapping to fix intermittent unrelocated pointers

The `FileAccessorCache`'s LRU eviction could discard a file's mapped
data after slide info had already been applied to it. Future accesses to
the file produced a fresh mapping, but failed to reapply the slide info.
This could result in pointers not correctly being slid, such as in
https://github.com/Vector35/binaryninja-api/issues/7689.

The LRU cache existed to stay within OS file descriptor limits, since
the old `MappedFile` held its fd open for the lifetime of the mapping.
There's no real reason for it to hold the file descriptor open like
this. Closing it after `mmap` is sufficient to avoid the file descriptor
limits.

`MappedFileRegion` replaces the combination of `FileAccessorCache`,
`WeakFileAccessor`, and `MappedFileAccessor`. It closes the fd
immediately after mmap, so all files can stay mapped without consuming
descriptors, making the cache unnecessary.

`MappedFileRegion` is owned directly by the `CacheEntry` for its full
lifetime. Slide info is applied exactly once to each `MappedFileRegion`.
---
 view/sharedcache/core/MappedFileAccessor.cpp | 111 ---------------------------
 1 file changed, 111 deletions(-)
 delete mode 100644 view/sharedcache/core/MappedFileAccessor.cpp

(limited to 'view/sharedcache/core/MappedFileAccessor.cpp')

diff --git a/view/sharedcache/core/MappedFileAccessor.cpp b/view/sharedcache/core/MappedFileAccessor.cpp
deleted file mode 100644
index 4f9f99a8..00000000
--- a/view/sharedcache/core/MappedFileAccessor.cpp
+++ /dev/null
@@ -1,111 +0,0 @@
-#include "MappedFileAccessor.h"
-
-std::shared_ptr<MappedFileAccessor> MappedFileAccessor::Open(const std::string& filePath)
-{
-	auto file = MappedFile::OpenFile(filePath);
-	if (!file.has_value())
-		return nullptr;
-	if (file->Map() != MapStatus::Success)
-		return nullptr;
-	return std::make_shared<MappedFileAccessor>(std::move(*file));
-}
-
-// TODO: Will obviously not work on 32bit binaries, need to make WritePointer64 and 32 equiv.
-void MappedFileAccessor::WritePointer(size_t address, size_t pointer)
-{
-	if (address + sizeof(size_t*) > Length())
-		throw UnmappedAccessException(address + sizeof(size_t*), Length());
-	m_dirty = true;
-	*reinterpret_cast<size_t*>(&m_file._mmap[address]) = pointer;
-}
-
-std::string MappedFileAccessor::ReadNullTermString(size_t address, const size_t maxLength) const
-{
-	if (address > Length())
-		return "";
-	// If we are not given a maxLength (i.e. -1) than we will set the max address to the length of the file.
-	const size_t maxAddr = (maxLength != -1) ? std::min(address + maxLength, Length()) : Length();
-	// Read a null-terminated string manually to avoid errors related to string length on Linux.
-	std::string str;
-	str.reserve(140);
-	for (size_t currAddr = address; currAddr < maxAddr; ++currAddr)
-	{
-		char c = m_file._mmap[currAddr];
-		if (c == '\0')
-			break;
-		str += c;
-	}
-	str.shrink_to_fit();
-	return str;
-}
-
-uint8_t MappedFileAccessor::ReadUInt8(size_t address) const
-{
-	return Read<uint8_t>(address);
-}
-
-int8_t MappedFileAccessor::ReadInt8(size_t address) const
-{
-	return Read<int8_t>(address);
-}
-
-uint16_t MappedFileAccessor::ReadUInt16(size_t address) const
-{
-	return Read<uint16_t>(address);
-}
-
-int16_t MappedFileAccessor::ReadInt16(size_t address) const
-{
-	return Read<int16_t>(address);
-}
-
-
-uint32_t MappedFileAccessor::ReadUInt32(size_t address) const
-{
-	return Read<uint32_t>(address);
-}
-
-int32_t MappedFileAccessor::ReadInt32(size_t address) const
-{
-	return Read<int32_t>(address);
-}
-
-uint64_t MappedFileAccessor::ReadUInt64(size_t address) const
-{
-	return Read<uint64_t>(address);
-}
-
-int64_t MappedFileAccessor::ReadInt64(size_t address) const
-{
-	return Read<int64_t>(address);
-}
-
-BinaryNinja::DataBuffer MappedFileAccessor::ReadBuffer(size_t addr, size_t length) const
-{
-	if (addr + length > Length())
-		throw UnmappedAccessException(addr + length, Length());
-	return {&m_file._mmap[addr], length};
-}
-
-std::pair<const uint8_t*, const uint8_t*> MappedFileAccessor::ReadSpan(size_t addr, size_t length)
-{
-	if (addr + length > Length())
-		throw UnmappedAccessException(addr + length, Length());
-	const uint8_t* data = &m_file._mmap[addr];
-	return {data, data + length};
-}
-
-void MappedFileAccessor::Read(void* dest, size_t addr, size_t length) const
-{
-	if (addr + length > Length())
-		throw UnmappedAccessException(addr + length, Length());
-	memcpy(dest, &m_file._mmap[addr], length);
-}
-
-template <typename T>
-T MappedFileAccessor::Read(size_t address) const
-{
-	T result;
-	Read(&result, address, sizeof(T));
-	return result;
-}
-- 
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