posix/mman: add mmap support for shm objects

Update #2859.

1 files changed, 30 insertions, 0 deletions

diff --git a/cpukit/posix/include/rtems/posix/shmimpl.h b/cpukit/posix/include/rtems/posix/shmimpl.h
index 6d81e5eb27..f16af8123d 100644
--- a/cpukit/posix/include/rtems/posix/shmimpl.h
+++ b/cpukit/posix/include/rtems/posix/shmimpl.h
@@ -96,6 +96,36 @@ static inline POSIX_Shm_Control* loc_to_shm(
   return (POSIX_Shm_Control*) loc->node_access;
 }
 
+static inline int POSIX_Shm_Attempt_delete(
+    POSIX_Shm_Control* shm
+)
+{
+  Objects_Control       *obj;
+  ISR_lock_Context       lock_ctx;
+  int err;
+
+  err = 0;
+
+  _Objects_Allocator_lock();
+  --shm->reference_count;
+  if ( shm->reference_count == 0 ) {
+    if ( (*shm->shm_object.ops->object_delete)( &shm->shm_object ) != 0 ) {
+      err = EIO;
+    }
+  }
+  /* check if the object has been unlinked yet. */
+  obj = _Objects_Get( shm->Object.id, &lock_ctx, &_POSIX_Shm_Information );
+  if ( obj == NULL ) {
+    /* if it was unlinked, then it can be freed. */
+    _POSIX_Shm_Free( shm );
+  } else {
+    /* it will be freed when it is unlinked. */
+    _ISR_lock_ISR_enable( &lock_ctx );
+  }
+  _Objects_Allocator_unlock();
+  return err;
+}
+
 /** @} */
 
 #ifdef __cplusplus