new util to name the data pages for now linux and especially android

 which supports it since a lot longer.

4 files changed, 28 insertions, 0 deletions

diff --git a/src/build-data/os/android.txt b/src/build-data/os/android.txt
index 54cdf4560..ea18cbde6 100644
--- a/src/build-data/os/android.txt
+++ b/src/build-data/os/android.txt
@@ -26,4 +26,5 @@ sockets
 threads
 thread_local
 filesystem
+prctl
 </target_features>
diff --git a/src/build-data/os/linux.txt b/src/build-data/os/linux.txt
index daf98f2b6..5752a0c94 100644
--- a/src/build-data/os/linux.txt
+++ b/src/build-data/os/linux.txt
@@ -19,6 +19,7 @@ sockets
 threads
 thread_local
 filesystem
+prctl
 </target_features>
 
 <aliases>
diff --git a/src/lib/utils/os_utils.cpp b/src/lib/utils/os_utils.cpp
index 403f7ac0c..0f3c2dfdc 100644
--- a/src/lib/utils/os_utils.cpp
+++ b/src/lib/utils/os_utils.cpp
@@ -67,6 +67,14 @@
   #include <mach/vm_statistics.h>
 #endif
 
+#if defined(BOTAN_TARGET_OS_HAS_PRCTL)
+  #include <sys/prctl.h>
+  #if !defined(PR_SET_VMA)
+    #define PR_SET_VMA 0x53564d41
+    #define PR_SET_VMA_ANON_NAME 0
+  #endif
+#endif
+
 namespace Botan {
 
 // Not defined in OS namespace for historical reasons
@@ -587,6 +595,8 @@ std::vector<void*> OS::allocate_locked_pages(size_t count)
 
       std::memset(ptr, 0, 3*page_size); // zero data page and both guard pages
 
+      // Attempts to name the data page
+      page_named(ptr, 3*page_size);
       // Make guard page preceeding the data page
       page_prohibit_access(static_cast<uint8_t*>(ptr));
       // Make guard page following the data page
@@ -655,6 +665,17 @@ void OS::free_locked_pages(const std::vector<void*>& pages)
       }
    }
 
+void OS::page_named(void* page, size_t size)
+   {
+   static constexpr char name[] = "Botan";
+#if defined(BOTAN_TARGET_OS_HAS_PRCTL)
+   int r = prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, reinterpret_cast<uintptr_t>(page), size, name);
+   BOTAN_UNUSED(r);
+#else
+   BOTAN_UNUSED(page, size);
+#endif
+   }
+
 #if defined(BOTAN_TARGET_OS_HAS_POSIX1) && !defined(BOTAN_TARGET_OS_IS_EMSCRIPTEN)
 
 namespace {
diff --git a/src/lib/utils/os_utils.h b/src/lib/utils/os_utils.h
index a70ce2ee1..62dfdeeaf 100644
--- a/src/lib/utils/os_utils.h
+++ b/src/lib/utils/os_utils.h
@@ -149,6 +149,11 @@ void page_prohibit_access(void* page);
 */
 void page_allow_access(void* page);
 
+/**
+* Set a ID to a page's range expressed by size bytes
+*/
+void page_named(void* page, size_t size);
+
 
 /**
 * Run a probe instruction to test for support for a CPU instruction.