[rtems commit] Return NULL for zero size allocations
Sebastian Huber
sebh at rtems.org
Thu May 6 13:14:56 UTC 2021
Module: rtems
Branch: master
Commit: 2c5199bb049efe8e29cd12461dc57bd6e30388e8
Changeset: http://git.rtems.org/rtems/commit/?id=2c5199bb049efe8e29cd12461dc57bd6e30388e8
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date: Wed May 5 08:49:52 2021 +0200
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.
---
cpukit/libcsupport/src/alignedalloc.c | 4 ++
cpukit/libcsupport/src/calloc.c | 9 ++--
cpukit/libcsupport/src/malloc.c | 4 ++
cpukit/libcsupport/src/malloc_deferred.c | 4 ++
cpukit/libcsupport/src/posix_memalign.c | 4 ++
cpukit/libcsupport/src/rtems_memalign.c | 4 ++
cpukit/libcsupport/src/rtemscalloc.c | 9 ++--
testsuites/libtests/malloctest/init.c | 81 ++++++++++----------------------
8 files changed, 56 insertions(+), 63 deletions(-)
diff --git a/cpukit/libcsupport/src/alignedalloc.c b/cpukit/libcsupport/src/alignedalloc.c
index b552fc2..9c9ea83 100644
--- a/cpukit/libcsupport/src/alignedalloc.c
+++ b/cpukit/libcsupport/src/alignedalloc.c
@@ -35,6 +35,10 @@
void *aligned_alloc( size_t alignment, size_t size )
{
+ if ( size == 0 ) {
+ return NULL;
+ }
+
return rtems_heap_allocate_aligned_with_boundary( size, alignment, 0 );
}
diff --git a/cpukit/libcsupport/src/calloc.c b/cpukit/libcsupport/src/calloc.c
index 693aa21..d5cefb3 100644
--- a/cpukit/libcsupport/src/calloc.c
+++ b/cpukit/libcsupport/src/calloc.c
@@ -35,14 +35,15 @@ void *calloc(
size_t length;
if ( nelem == 0 ) {
- length = 0;
- } else if ( elsize > SIZE_MAX / nelem ) {
+ return NULL;
+ }
+
+ if ( elsize > SIZE_MAX / nelem ) {
errno = ENOMEM;
return NULL;
- } else {
- length = nelem * elsize;
}
+ length = nelem * elsize;
cptr = malloc( length );
RTEMS_OBFUSCATE_VARIABLE( cptr );
if ( RTEMS_PREDICT_FALSE( cptr == NULL ) ) {
diff --git a/cpukit/libcsupport/src/malloc.c b/cpukit/libcsupport/src/malloc.c
index 795254f..3e55a94 100644
--- a/cpukit/libcsupport/src/malloc.c
+++ b/cpukit/libcsupport/src/malloc.c
@@ -30,6 +30,10 @@ void *malloc(
{
void *return_this;
+ if ( size == 0 ) {
+ return NULL;
+ }
+
return_this = rtems_heap_allocate_aligned_with_boundary( size, 0, 0 );
if ( !return_this ) {
errno = ENOMEM;
diff --git a/cpukit/libcsupport/src/malloc_deferred.c b/cpukit/libcsupport/src/malloc_deferred.c
index aab7640..b319d12 100644
--- a/cpukit/libcsupport/src/malloc_deferred.c
+++ b/cpukit/libcsupport/src/malloc_deferred.c
@@ -106,6 +106,10 @@ void *rtems_heap_allocate_aligned_with_boundary(
void *rtems_malloc( size_t size )
{
+ if ( size == 0 ) {
+ return NULL;
+ }
+
return rtems_heap_allocate_aligned_with_boundary( size, 0, 0 );
}
#endif
diff --git a/cpukit/libcsupport/src/posix_memalign.c b/cpukit/libcsupport/src/posix_memalign.c
index 316ed73..4e89413 100644
--- a/cpukit/libcsupport/src/posix_memalign.c
+++ b/cpukit/libcsupport/src/posix_memalign.c
@@ -37,6 +37,10 @@ int posix_memalign(
*memptr = NULL;
+ if ( size == 0 ) {
+ return 0;
+ }
+
if ( alignment < sizeof( void * ) ) {
return EINVAL;
}
diff --git a/cpukit/libcsupport/src/rtems_memalign.c b/cpukit/libcsupport/src/rtems_memalign.c
index aa938ac..aa67c74 100644
--- a/cpukit/libcsupport/src/rtems_memalign.c
+++ b/cpukit/libcsupport/src/rtems_memalign.c
@@ -40,6 +40,10 @@ int rtems_memalign(
*pointer = NULL;
+ if ( size == 0 ) {
+ return 0;
+ }
+
/*
* Perform the aligned allocation requested
*/
diff --git a/cpukit/libcsupport/src/rtemscalloc.c b/cpukit/libcsupport/src/rtemscalloc.c
index 836f1da..7e05a14 100644
--- a/cpukit/libcsupport/src/rtemscalloc.c
+++ b/cpukit/libcsupport/src/rtemscalloc.c
@@ -47,13 +47,14 @@ void *rtems_calloc( size_t nelem, size_t elsize )
void *p;
if ( nelem == 0 ) {
- length = 0;
- } else if ( elsize > SIZE_MAX / nelem ) {
return NULL;
- } else {
- length = nelem * elsize;
}
+ if ( elsize > SIZE_MAX / nelem ) {
+ return NULL;
+ }
+
+ length = nelem * elsize;
p = rtems_malloc( length );
RTEMS_OBFUSCATE_VARIABLE( p );
if ( RTEMS_PREDICT_FALSE( p == NULL ) ) {
diff --git a/testsuites/libtests/malloctest/init.c b/testsuites/libtests/malloctest/init.c
index c9dcb63..a337641 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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