posix/mman: add mmap support for shm objects

Update #2859.

1 files changed, 41 insertions, 0 deletions

diff --git a/cpukit/libcsupport/include/rtems/libio_.h b/cpukit/libcsupport/include/rtems/libio_.h
index c2fb975bf7..695a4c45a5 100644
--- a/cpukit/libcsupport/include/rtems/libio_.h
+++ b/cpukit/libcsupport/include/rtems/libio_.h
@@ -304,6 +304,47 @@ void rtems_libio_free(
   rtems_libio_t *iop
 );
 
+/**
+ * Garbage collects the free libio in case it was previously freed but there
+ * were still references to it.
+ */
+void rtems_libio_check_deferred_free( rtems_libio_t *iop );
+
+/**
+ * Increment the reference count tracking number of mmap mappings of a file.
+ * Returns the updated reference count value.
+ */
+static inline uint32_t rtems_libio_increment_mapping_refcnt(rtems_libio_t *iop)
+{
+  uint32_t refcnt;
+  rtems_libio_lock();
+  refcnt = ++iop->mapping_refcnt;
+  rtems_libio_unlock();
+  return refcnt;
+}
+
+/**
+ * Decrement the reference count tracking number of mmap mappings of a file.
+ * Returns the updated reference count value.
+ */
+static inline uint32_t rtems_libio_decrement_mapping_refcnt(rtems_libio_t *iop)
+{
+  uint32_t refcnt;
+  rtems_libio_lock();
+  refcnt = --iop->mapping_refcnt;
+  rtems_libio_unlock();
+  return refcnt;
+}
+
+static inline bool rtems_libio_is_mapped(rtems_libio_t *iop)
+{
+  bool is_mapped;
+  rtems_libio_lock();
+  is_mapped = iop->mapping_refcnt != 0;
+  rtems_libio_unlock();
+  return is_mapped;
+}
+
 /*
  *  File System Routine Prototypes
  */