Add hat::process::is_writable

BasedInc · Oct 8, 2024 · f4cee10 · f4cee10
1 parent d1c34d0
commit f4cee10
Show file tree

Hide file tree

Showing 2 changed files with 24 additions and 0 deletions.
diff --git a/include/libhat/Process.hpp b/include/libhat/Process.hpp
@@ -33,6 +33,9 @@ namespace hat::process {
     /// Returns whether the entirety of a given memory region is readable
     [[nodiscard]] bool is_readable(std::span<const std::byte> region);
 
+    /// Returns whether the entirety of a given memory region is writable
+    [[nodiscard]] bool is_writable(std::span<const std::byte> region);
+
     /// Returns the module for the current process's base executable
     [[nodiscard]] hat::process::module get_process_module();
 

diff --git a/src/os/win32/Process.cpp b/src/os/win32/Process.cpp
@@ -64,6 +64,27 @@ namespace hat::process {
         return true;
     }
 
+    bool is_writable(const std::span<const std::byte> region) {
+        constexpr DWORD writeFlags = PAGE_EXECUTE_READWRITE
+            | PAGE_EXECUTE_WRITECOPY
+            | PAGE_READWRITE
+            | PAGE_WRITECOPY;
+        for (auto* addr = region.data(); addr < region.data() + region.size();) {
+            MEMORY_BASIC_INFORMATION mbi{};
+            if (!VirtualQuery(addr, &mbi, sizeof(mbi))) {
+                return false;
+            }
+            if (mbi.State != MEM_COMMIT) {
+                return false;
+            }
+            if (!(mbi.Protect & writeFlags)) {
+                return false;
+            }
+            addr = static_cast<const std::byte*>(mbi.BaseAddress) + mbi.RegionSize;
+        }
+        return true;
+    }
+
     hat::process::module get_process_module() {
         return module{reinterpret_cast<uintptr_t>(GetModuleHandleW(nullptr))};
     }