From 2c5199bb049efe8e29cd12461dc57bd6e30388e8 Mon Sep 17 00:00:00 2001
From: Sebastian Huber <sebastian.huber@embedded-brains.de>
Date: Wed, 5 May 2021 08:49:52 +0200
Subject: Return NULL for zero size allocations

In POSIX, zero size memory allocations are implementation-defined
behaviour.  The implementation has two options:

https://pubs.opengroup.org/onlinepubs/9699919799/functions/malloc.html

https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_memalign.html

Linux and FreeBSD return a unique pointer for zero size memory
allocations.   Return NULL on RTEMS to more likely catch the use of a
zero size memory area by erroneous applications.

Update #4390.
---
 testsuites/libtests/malloctest/init.c | 81 +++++++++++------------------------
 1 file changed, 26 insertions(+), 55 deletions(-)

(limited to 'testsuites')

diff --git a/testsuites/libtests/malloctest/init.c b/testsuites/libtests/malloctest/init.c
index c9dcb63b2c..a33764177d 100644
--- a/testsuites/libtests/malloctest/init.c
+++ b/testsuites/libtests/malloctest/init.c
@@ -1153,10 +1153,7 @@ static void test_rtems_malloc(void)
   void *p;
 
   p = rtems_malloc(0);
-  rtems_test_assert(p != NULL);
-
-  RTEMS_OBFUSCATE_VARIABLE(p);
-  free(p);
+  rtems_test_assert(p == NULL);
 
   errno = 0;
   p = rtems_malloc(SIZE_MAX / 2);
@@ -1176,22 +1173,13 @@ static void test_rtems_calloc(void)
   int *i;
 
   p = rtems_calloc(0, 0);
-  rtems_test_assert(p != NULL);
-
-  RTEMS_OBFUSCATE_VARIABLE(p);
-  free(p);
+  rtems_test_assert(p == NULL);
 
   p = rtems_calloc(0, 1);
-  rtems_test_assert(p != NULL);
-
-  RTEMS_OBFUSCATE_VARIABLE(p);
-  free(p);
+  rtems_test_assert(p == NULL);
 
   p = rtems_calloc(1, 0);
-  rtems_test_assert(p != NULL);
-
-  RTEMS_OBFUSCATE_VARIABLE(p);
-  free(p);
+  rtems_test_assert(p == NULL);
 
   errno = 0;
   p = rtems_calloc(1, SIZE_MAX / 2);
@@ -1323,73 +1311,56 @@ static void test_alloc_zero_size(void)
   int eno;
 
   size = 0;
+  errno = -1;
 
   RTEMS_OBFUSCATE_VARIABLE( size );
   p = malloc( size );
-  rtems_test_assert( p != NULL );
-
-  RTEMS_OBFUSCATE_VARIABLE( p );
-  free( p );
+  rtems_test_assert( p == NULL );
+  rtems_test_assert( errno == -1 );
 
   RTEMS_OBFUSCATE_VARIABLE( size );
-  p = calloc( 1, size );
-  rtems_test_assert( p != NULL );
-
-  RTEMS_OBFUSCATE_VARIABLE( p );
-  free( p );
+  p = calloc( size, 1 );
+  rtems_test_assert( p == NULL );
+  rtems_test_assert( errno == -1 );
 
   RTEMS_OBFUSCATE_VARIABLE( size );
   p = rtems_malloc( size );
-  rtems_test_assert( p != NULL );
-
-  RTEMS_OBFUSCATE_VARIABLE( p );
-  free( p );
+  rtems_test_assert( p == NULL );
+  rtems_test_assert( errno == -1 );
 
   RTEMS_OBFUSCATE_VARIABLE( size );
   p = rtems_calloc( 1, size );
-  rtems_test_assert( p != NULL );
-
-  RTEMS_OBFUSCATE_VARIABLE( p );
-  free( p );
+  rtems_test_assert( p == NULL );
+  rtems_test_assert( errno == -1 );
 
   RTEMS_OBFUSCATE_VARIABLE( size );
-  p = NULL;
+  p = (void *)(uintptr_t) 1;
   eno = posix_memalign( &p, 32, size );
   rtems_test_assert( eno == 0 );
-  rtems_test_assert( p != NULL );
-
-  RTEMS_OBFUSCATE_VARIABLE( p );
-  free( p );
+  rtems_test_assert( p == NULL );
+  rtems_test_assert( errno == -1 );
 
   RTEMS_OBFUSCATE_VARIABLE( size );
-  p = NULL;
+  p = (void *)(uintptr_t) 1;
   eno = rtems_memalign( &p, 32, size );
   rtems_test_assert( eno == 0 );
-  rtems_test_assert( p != NULL );
-
-  RTEMS_OBFUSCATE_VARIABLE( p );
-  free( p );
+  rtems_test_assert( p == NULL );
+  rtems_test_assert( errno == -1 );
 
   RTEMS_OBFUSCATE_VARIABLE( size );
   p = aligned_alloc( 32, size );
-  rtems_test_assert( p != NULL );
-
-  RTEMS_OBFUSCATE_VARIABLE( p );
-  free( p );
+  rtems_test_assert( p == NULL );
+  rtems_test_assert( errno == -1 );
 
   RTEMS_OBFUSCATE_VARIABLE( size );
   p = realloc( NULL, size );
-  rtems_test_assert( p != NULL );
-
-  RTEMS_OBFUSCATE_VARIABLE( p );
-  free( p );
+  rtems_test_assert( p == NULL );
+  rtems_test_assert( errno == -1 );
 
   RTEMS_OBFUSCATE_VARIABLE( size );
   p = reallocarray( NULL, 1, size );
-  rtems_test_assert( p != NULL );
-
-  RTEMS_OBFUSCATE_VARIABLE( p );
-  free( p );
+  rtems_test_assert( p == NULL );
+  rtems_test_assert( errno == -1 );
 }
 
 rtems_task Init(
-- 
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