libcsupport: Add sbrk greedy support to consume all sbrk memory

- Move the heap sbrk code into a separate routnine.

- Update heap and workspace greedy allocators to use the common
  sbrk greedy support.

Closes #3982

1 files changed, 63 insertions, 0 deletions

diff --git a/cpukit/libcsupport/src/rtems_heap_sbrk_greedy.c b/cpukit/libcsupport/src/rtems_heap_sbrk_greedy.c
new file mode 100644
index 0000000000..49ae2a7c87
--- /dev/null
+++ b/cpukit/libcsupport/src/rtems_heap_sbrk_greedy.c
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @brief Greedy Allocate that Empties the sbrk system call
+ *
+ * @ingroup MallocSupport
+ *
+ * @brief Greedy allocation os sbrk system call memory
+ *
+ * The call consumes all the avialable sbrk memory extending
+ * the supplied heap with it. There is no free as sbrk memory
+ * is only ever allocated.
+ */
+
+/*
+ * Copyright (c) 2021 Chris Johns.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "malloc_p.h"
+
+void rtems_heap_sbrk_greedy_allocate(
+  Heap_Control *heap,
+  size_t alloc_size
+)
+{
+  while ( alloc_size > 0 ) {
+    void *p = (*rtems_malloc_extend_handler)( heap, alloc_size );
+    if ( p == NULL ) {
+      alloc_size >>= 1;
+    } else {
+      if ( rtems_malloc_dirty_helper != NULL ) {
+	(*rtems_malloc_dirty_helper)( p, alloc_size );
+      }
+    }
+  }
+}