[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`.

1 files changed, 0 insertions, 86 deletions

diff --git a/view/sharedcache/core/MappedFile.h b/view/sharedcache/core/MappedFile.h
deleted file mode 100644
index ced79f52..00000000
--- a/view/sharedcache/core/MappedFile.h
+++ /dev/null
@@ -1,86 +0,0 @@
-#pragma once
-
-#include <string>
-#include <cstdint>
-#include <cstdio>
-#include <optional>
-
-// Call this when initializing the plugin so that the process file descriptor limit is raised.
-uint64_t AdjustFileDescriptorLimit();
-
-enum MapStatus : int
-{
-	Success,
-	// TODO: Split this error out into more contextual errors.
-	Error,
-};
-
-struct MappedFile
-{
-	uint8_t* _mmap = nullptr;
-	size_t len = 0;
-
-#ifdef _MSC_VER
-	HANDLE hFile = INVALID_HANDLE_VALUE;
-#else
-	FILE* fd = nullptr;
-#endif
-
-	MappedFile() = default;
-
-	~MappedFile();
-
-	MappedFile(const MappedFile&) = delete;
-
-	MappedFile& operator=(const MappedFile&) = delete;
-
-	MappedFile(MappedFile&& other) noexcept : _mmap(other._mmap), len(other.len)
-	{
-#ifdef _MSC_VER
-		hFile = other.hFile;
-		// Don't close the hFile in the move.
-		other.hFile = nullptr;
-#else
-		fd = other.fd;
-		// Don't close the fd in the move.
-		other.fd = nullptr;
-#endif
-		other._mmap = nullptr;
-	}
-
-	// I hate C++
-	MappedFile& operator=(MappedFile&& other) noexcept
-	{
-		if (this != &other)
-		{
-			Unmap();
-#ifdef _MSC_VER
-			if (hFile != nullptr)
-			{
-				CloseHandle(hFile);
-			}
-			hFile = other.hFile;
-			// Don't close the hFile in the move.
-			other.hFile = nullptr;
-#else
-			if (fd != nullptr)
-			{
-				fclose(fd);
-			}
-			fd = other.fd;
-			// Don't close the fd in the move.
-			other.fd = nullptr;
-#endif
-			len = other.len;
-			_mmap = other._mmap;
-			other._mmap = nullptr;
-		}
-		return *this;
-	}
-
-	static std::optional<MappedFile> OpenFile(const std::string& path);
-
-	MapStatus Map();
-
-	MapStatus Unmap();
-};