At startup, test if lock_mem() at least seems to work. If it doesn't,

immediately fall back the the plain malloc-based allocator, which is
typically quite a bit faster.

3 files changed, 16 insertions, 1 deletions

diff --git a/src/libstate/libstate.cpp b/src/libstate/libstate.cpp
index b461c1ef8..7706cef28 100644
--- a/src/libstate/libstate.cpp
+++ b/src/libstate/libstate.cpp
@@ -14,6 +14,7 @@
 #include <botan/internal/mutex.h>
 #include <botan/internal/mux_noop.h>
 #include <botan/internal/stl_util.h>
+#include <botan/internal/mlock.h>
 #include <algorithm>
 
 #if defined(BOTAN_HAS_SELFTESTS)
@@ -252,7 +253,7 @@ void Library_State::initialize(bool thread_safe)
    config_lock = mutex_factory->make();
 
    cached_default_allocator = 0;
-   default_allocator_name = "locking";
+   default_allocator_name = has_mlock() ? "locking" : "malloc";
 
    add_allocator(new Malloc_Allocator);
    add_allocator(new Locking_Allocator(mutex_factory->make()));
diff --git a/src/utils/mlock.cpp b/src/utils/mlock.cpp
index 5d6fc3591..bc6ddc67e 100644
--- a/src/utils/mlock.cpp
+++ b/src/utils/mlock.cpp
@@ -16,6 +16,15 @@
 
 namespace Botan {
 
+bool has_mlock()
+   {
+   byte buf[4096];
+   if(!lock_mem(&buf, sizeof(buf)))
+      return false;
+   unlock_mem(&buf, sizeof(buf));
+   return true;
+   }
+
 /*
 * Lock an area of memory into RAM
 */
diff --git a/src/utils/mlock.h b/src/utils/mlock.h
index 66ced9e63..fea56d438 100644
--- a/src/utils/mlock.h
+++ b/src/utils/mlock.h
@@ -13,6 +13,11 @@
 namespace Botan {
 
 /**
+* Check if we can at least potentially lock memory
+*/
+bool has_mlock();
+
+/**
 * Lock memory into RAM if possible
 * @param addr the start of the memory block
 * @param length the length of the memory block in bytes