Give base::SharedMemory::CreateAnonymous an executable flag

NaCl on Mac and Linux needs to create a shared memory object that it can
later make executable with mprotect.  Express this need in the interface it
uses.  Add a test that pages mapped from such an object can later be passed
to mprotect with PROT_EXEC.

This lays the groundwork for a later change that will sometimes use a
different method to allocate an object on Linux when it needs to be
executable.  On some Linux distributions, shm_open yields objects whose
mappings cannot be made executable.

BUG= http://code.google.com/p/chromium/issues/detail?id=103377
TEST= SharedMemory.AnonymousExecutable

R=mark@chromium.org,jam@chromium.org,amit@chromium.org,ben@chromium.org

Review URL: http://codereview.chromium.org/8585002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@112570 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 22 insertions, 0 deletions

diff --git a/base/shared_memory_unittest.cc b/base/shared_memory_unittest.cc
index 9f69a5d..41b8ba5 100644
--- a/base/shared_memory_unittest.cc
+++ b/base/shared_memory_unittest.cc
@@ -15,6 +15,10 @@
 #include "base/mac/scoped_nsautorelease_pool.h"
 #endif
 
+#if defined(OS_POSIX)
+#include <sys/mman.h>
+#endif
+
 static const int kNumThreads = 5;
 static const int kNumTasks = 5;
 
@@ -332,6 +336,24 @@ TEST(SharedMemoryTest, AnonymousPrivate) {
   }
 }
 
+#if defined(OS_POSIX)
+// Create a shared memory object, mmap it, and mprotect it to PROT_EXEC.
+TEST(SharedMemoryTest, AnonymousExecutable) {
+  const uint32 kTestSize = 1 << 16;
+
+  SharedMemory shared_memory;
+  SharedMemoryCreateOptions options;
+  options.size = kTestSize;
+  options.executable = true;
+
+  EXPECT_TRUE(shared_memory.Create(options));
+  EXPECT_TRUE(shared_memory.Map(shared_memory.created_size()));
+
+  EXPECT_EQ(0, mprotect(shared_memory.memory(), shared_memory.created_size(),
+                        PROT_READ | PROT_EXEC));
+}
+#endif
+
 // On POSIX it is especially important we test shmem across processes,
 // not just across threads.  But the test is enabled on all platforms.
 class SharedMemoryProcessTest : public MultiProcessTest {