[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, 8 deletions

diff --git a/view/sharedcache/core/SharedCacheController.cpp b/view/sharedcache/core/SharedCacheController.cpp
index d300017e..8886748f 100644
--- a/view/sharedcache/core/SharedCacheController.cpp
+++ b/view/sharedcache/core/SharedCacheController.cpp
@@ -39,14 +39,6 @@ void DeleteController(const FileMetadata& file)
 			LogWarnF("Deleting SharedCacheController for view {:#x}, but there are still {} references", id,
 				controller->m_refs.load());
 
-		// Go through the file accessor cache and remove the entries we reference.
-		auto& fileAccessorCache = FileAccessorCache::Global();
-		for (const auto& entry : controller->GetCache().GetEntries())
-		{
-			auto accessorId = GetCacheAccessorID(entry.GetFilePath());
-			fileAccessorCache.RemoveAccessor(accessorId);
-		}
-
 		controllers.erase(it);
 		LogDebugF("Deleted SharedCacheController for view {:?}", file.GetFilename().c_str());
 	}