[PATCH] added malloc usable size and test

[Gedare Bloom]

add bit more description and ticket # in commit msg

On Sun, Feb 13, 2022 at 8:14 PM zack leung <zakthertemsdev at gmail.com> wrote:
>
> ---
>  cpukit/include/rtems/libcsupport.h        |  8 ++++++-
>  cpukit/libcsupport/src/mallocusablesize.c | 28 +++++++++++++++++++++++
>  spec/build/cpukit/librtemscpu.yml         |  1 +
>  testsuites/libtests/malloctest/init.c     | 15 +++++++++++-
>  4 files changed, 50 insertions(+), 2 deletions(-)
>  create mode 100644 cpukit/libcsupport/src/mallocusablesize.c
>
> diff --git a/cpukit/include/rtems/libcsupport.h b/cpukit/include/rtems/libcsupport.h
> index f4be4cfc9a..1fe0f6735f 100644
> --- a/cpukit/include/rtems/libcsupport.h
> +++ b/cpukit/include/rtems/libcsupport.h
> @@ -73,7 +73,12 @@ extern size_t malloc_free_space(void);
>   * Find amount of free heap remaining.
>   */
>  extern int malloc_info(Heap_Information_block *the_info);
> -
> +/**
> + * @brief Get malloc status information.
this brief should probably just be the below statement?

> + *
> + * Find the usable size of the block of memory .
space before .

> + */
> +extern size_t malloc_usable_size(void *ptr);
>  /*
>   *  Prototypes required to install newlib reentrancy user extension
>   */
> @@ -185,6 +190,7 @@ bool rtems_resource_snapshot_equal(
>   */
>  bool rtems_resource_snapshot_check(const rtems_resource_snapshot *snapshot);
>
> +
avoid spurious whitespace changes

>  /** @} */
>
>  #ifdef __cplusplus
> diff --git a/cpukit/libcsupport/src/mallocusablesize.c b/cpukit/libcsupport/src/mallocusablesize.c
> new file mode 100644
> index 0000000000..10114182a6
> --- /dev/null
> +++ b/cpukit/libcsupport/src/mallocusablesize.c
> @@ -0,0 +1,28 @@
> +/*
> + *  COPYRIGHT (c) 1989-2010.
> + *  On-Line Applications Research Corporation (OAR).
Is this your code/copyright?

> + *
> + *  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.
> + */
Prefer 2-bsd

> +#ifdef HAVE_CONFIG_H
> +#include "config.h"
> +#endif
> +
> +#include <rtems/libcsupport.h>
> +#include <rtems/malloc.h>
> +#include <rtems/score/heapimpl.h>
> +
> +Heap_Control *heap_ptr;
why a global variable here?

> +size_t malloc_usable_size(void *ptr) {
> +  uintptr_t size;

I'd prefer a blank space after the variables. I don't know if that is
part of our conventions.

> +  if (ptr == NULL) {
> +    return 0;
> +  }
> +
> +  heap_ptr = malloc_get_heap_pointer();
> +  _Heap_Size_of_alloc_area(heap_ptr, ptr, &size);
> +
> +  return size;
type mismatch between size_t and uintptr_t

> +}
> diff --git a/spec/build/cpukit/librtemscpu.yml b/spec/build/cpukit/librtemscpu.yml
> index 7d6dbae0db..5902008c94 100644
> --- a/spec/build/cpukit/librtemscpu.yml
> +++ b/spec/build/cpukit/librtemscpu.yml
> @@ -670,6 +670,7 @@ source:
>  - cpukit/libcsupport/src/lseek.c
>  - cpukit/libcsupport/src/lstat.c
>  - cpukit/libcsupport/src/malloc.c
> +- cpukit/libcsupport/src/mallocusablesize.c
>  - cpukit/libcsupport/src/malloc_deferred.c
>  - cpukit/libcsupport/src/malloc_dirtier.c
>  - cpukit/libcsupport/src/malloc_walk.c
> diff --git a/testsuites/libtests/malloctest/init.c b/testsuites/libtests/malloctest/init.c
> index a33764177d..2202546719 100644
> --- a/testsuites/libtests/malloctest/init.c
> +++ b/testsuites/libtests/malloctest/init.c
> @@ -1362,6 +1362,18 @@ static void test_alloc_zero_size(void)
>    rtems_test_assert( p == NULL );
>    rtems_test_assert( errno == -1 );
>  }
> +static void test_usablesize(void)
> +{
> +  int * a = malloc(sizeof( int )*100);
> +  int alloc_size=sizeof( int ) *100 ;
> +  rtems_test_assert(  malloc_usable_size(a) <= alloc_size + CPU_HEAP_ALIGNMENT);
> +  free(a);
> +
> +  char * b = malloc(sizeof(char)*100);
> +  int alloc_size2=sizeof(char) *100 ;
> +  rtems_test_assert( malloc_usable_size ( b ) <= alloc_size2 + CPU_HEAP_ALIGNMENT);
> +  free(b);
> +}
>
>  rtems_task Init(
>    rtems_task_argument argument
> @@ -1405,6 +1417,7 @@ rtems_task Init(
>    test_protected_heap_info();
>    test_rtems_heap_allocate_aligned_with_boundary();
>    test_rtems_malloc();
> +  test_usablesize();
>    test_rtems_calloc();
>    test_greedy_allocate();
>    test_alloc_zero_size();
> @@ -1524,4 +1537,4 @@ RTEMS_SYSINIT_ITEM(
>    test_early_malloc,
>    RTEMS_SYSINIT_INITIAL_EXTENSIONS,
>    RTEMS_SYSINIT_ORDER_FIRST
> -);
> +);
whitespace change

> \ No newline at end of file
> --
> 2.35.1
>
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