posix: shared memory support

Add POSIX shared memory manager (Shm). Includes a hook-based
approach for the backing memory storage that defaults to the
Workspace, and a test is provided using the heap. A test is
also provided for the basic use of mmap'ing a shared memory
object. This test currently fails at the mmap stage due to
no support for mmap.

1 files changed, 90 insertions, 0 deletions

diff --git a/cpukit/posix/src/shmheap.c b/cpukit/posix/src/shmheap.c
new file mode 100644
index 0000000000..3449c15cca
--- /dev/null
+++ b/cpukit/posix/src/shmheap.c
@@ -0,0 +1,90 @@
+/**
+ * @file
+ */
+
+/*
+ * Copyright (c) 2016 Gedare Bloom.
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <errno.h>
+#include <stdlib.h>
+#include <rtems/posix/shmimpl.h>
+
+int _POSIX_Shm_Object_create_from_heap(
+  POSIX_Shm_Object *shm_obj,
+  size_t size
+)
+{
+  void *p = calloc( 1, size ); /* get zero'd memory */
+  if ( p != NULL ) {
+    shm_obj->handle = p;
+    shm_obj->size = size;
+  } else {
+    errno = EIO;
+  }
+  return 0;
+}
+
+int _POSIX_Shm_Object_delete_from_heap( POSIX_Shm_Object *shm_obj )
+{
+  /* zero out memory before releasing it. */
+  memset( shm_obj->handle, 0, shm_obj->size );
+  free( shm_obj->handle );
+  shm_obj->handle = NULL;
+  shm_obj->size = 0;
+  return 0;
+}
+
+int _POSIX_Shm_Object_resize_from_heap(
+  POSIX_Shm_Object *shm_obj,
+  size_t size
+)
+{
+  void *p;
+  int err = 0;
+
+  if ( size < shm_obj->size ) {
+    /* zero out if shrinking */
+    p = (void*)((uintptr_t)shm_obj->handle + (uintptr_t)size);
+    memset( p, 0, shm_obj->size - size );
+  }
+  p = realloc( shm_obj->handle, size );
+  if ( p != NULL ) {
+    shm_obj->handle = p;
+    if ( size > shm_obj->size ) {
+      /* initialize added memory */ 
+      memset( p, 0, size - shm_obj->size );
+    }
+    shm_obj->size = size;
+  } else {
+    err = EIO;
+  }
+  return err;
+}
+
+int _POSIX_Shm_Object_read_from_heap(
+  POSIX_Shm_Object *shm_obj,
+  void *buf,
+  size_t count
+)
+{
+  if ( shm_obj == NULL || shm_obj->handle == NULL )
+    return 0;
+
+  if ( shm_obj->size < count ) {
+    count = shm_obj->size;
+  }
+
+  memcpy( buf, shm_obj->handle, count );
+
+  return count;
+}
+