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, 182 insertions, 0 deletions

diff --git a/cpukit/posix/include/rtems/posix/shm.h b/cpukit/posix/include/rtems/posix/shm.h
new file mode 100644
index 0000000000..dfdd58ed2a
--- /dev/null
+++ b/cpukit/posix/include/rtems/posix/shm.h
@@ -0,0 +1,182 @@
+/**
+ * @file
+ *
+ * @brief Internal Support for POSIX Shared Memory
+ */
+
+/*
+ * 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.
+ */
+
+#ifndef _RTEMS_POSIX_SHM_H
+#define _RTEMS_POSIX_SHM_H
+
+#include <rtems/score/object.h>
+#include <rtems/score/threadq.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @defgroup POSIXShmPrivate POSIX Shared Memory Private Support
+ *
+ * @ingroup POSIXAPI
+ *
+ * Internal implementation support for POSIX shared memory.
+ * @{
+ */
+typedef struct POSIX_Shm_Object_operations POSIX_Shm_Object_operations;
+extern const POSIX_Shm_Object_operations _POSIX_Shm_Object_operations;
+
+/**
+ * @brief Encapsulation for the storage and manipulation of shm objects.
+ */
+typedef struct {
+  /**
+   * @brief The handle is private for finding object storage.
+   */
+  void                               *handle;
+
+  /**
+   * @brief The number of bytes allocated to the object. A size of 0 with
+   * a handle of NULL means no object is allocated.
+   */
+  size_t                              size;
+
+  /**
+   * @brief Implementation-specific operations on shm objects.
+   */
+  const POSIX_Shm_Object_operations  *ops;
+} POSIX_Shm_Object;
+
+/**
+ * @brief Operations on POSIX Shared Memory Objects.
+ */
+struct POSIX_Shm_Object_operations {
+  /**
+   * @brief Allocates a new @a shm_obj with initial @a size.
+   *
+   * New shared memory is initialized to zeroes.
+   *
+   * Returns 0 for success.
+   */
+  int ( *object_create ) ( POSIX_Shm_Object *shm_obj, size_t size );
+
+  /**
+   * @brief Changes the @a shm_obj size to @a size.
+   *
+   * Zeroes out the portion of the shared memory object that shrinks or grows.
+   *
+   * Returns 0 for success.
+   */
+  int ( *object_resize ) ( POSIX_Shm_Object *shm_obj, size_t size );
+
+  /**
+   * @brief Deletes the @a shm_obj.
+   *
+   * Zeroes out the memory.
+   *
+   * Returns 0 for success.
+   */
+  int ( *object_delete ) ( POSIX_Shm_Object *shm_obj );
+
+  /**
+   * @brief Copies up to @count bytes of the @a shm_obj data into @a buf.
+   *
+   * Returns the number of bytes read (copied) into @a buf.
+   */
+  int ( *object_read ) ( POSIX_Shm_Object *shm_obj, void *buf, size_t count );
+};
+
+/**
+ * @brief Control for a POSIX Shared Memory Object
+ */
+typedef struct {
+   Objects_Control      Object;
+   Thread_queue_Control Wait_queue;
+
+   int                  reference_count;
+
+   POSIX_Shm_Object     shm_object;
+
+   uid_t                uid;
+   gid_t                gid;
+   mode_t               mode;
+
+   time_t               atime;
+   time_t               mtime;
+   time_t               ctime;
+} POSIX_Shm_Control;
+
+/**
+ * @brief object_create operation for shm objects stored in RTEMS Workspace.
+ */
+extern int _POSIX_Shm_Object_create_from_workspace(
+  POSIX_Shm_Object *shm_obj,
+  size_t size
+);
+
+/**
+ * @brief object_delete operation for shm objects stored in RTEMS Workspace.
+ */
+extern int _POSIX_Shm_Object_delete_from_workspace( POSIX_Shm_Object *shm_obj );
+
+/**
+ * @brief object_resize operation for shm objects stored in RTEMS Workspace.
+ */
+extern int _POSIX_Shm_Object_resize_from_workspace(
+  POSIX_Shm_Object *shm_obj,
+  size_t size
+);
+
+/**
+ * @brief object_read operation for shm objects stored in RTEMS Workspace.
+ */
+extern int _POSIX_Shm_Object_read_from_workspace(
+  POSIX_Shm_Object *shm_obj,
+  void *buf,
+  size_t count
+);
+
+/**
+ * @brief object_create operation for shm objects stored in C program heap.
+ */
+extern int _POSIX_Shm_Object_create_from_heap(
+  POSIX_Shm_Object *shm_obj,
+  size_t size
+);
+
+/**
+ * @brief object_delete operation for shm objects stored in C program heap.
+ */
+extern int _POSIX_Shm_Object_delete_from_heap( POSIX_Shm_Object *shm_obj );
+
+/**
+ * @brief object_resize operation for shm objects stored in C program heap.
+ */
+extern int _POSIX_Shm_Object_resize_from_heap(
+  POSIX_Shm_Object *shm_obj,
+  size_t size
+);
+
+/**
+ * @brief object_read operation for shm objects stored in C program heap.
+ */
+extern int _POSIX_Shm_Object_read_from_heap(
+  POSIX_Shm_Object *shm_obj,
+  void *buf,
+  size_t count
+);
+
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif