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authorMattias Andrée <maandree@member.fsf.org>2016-01-01 17:55:37 +0100
committerMattias Andrée <maandree@member.fsf.org>2016-01-01 17:55:37 +0100
commit868abdea9811937039a1df84b15ad17f9b9c7a27 (patch)
treea7b98560d5eb155724663c4345283afbd68faa79 /src
parentm (diff)
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extension: free will perserve errno
Signed-off-by: Mattias Andrée <maandree@member.fsf.org>
Diffstat (limited to 'src')
-rw-r--r--src/malloc.c4
-rw-r--r--src/slibc-alloc.c8
2 files changed, 12 insertions, 0 deletions
diff --git a/src/malloc.c b/src/malloc.c
index 6d1f220..9b45607 100644
--- a/src/malloc.c
+++ b/src/malloc.c
@@ -254,6 +254,8 @@ void* realloc(void* ptr, size_t size)
/**
* Free a memory allocation.
+ *
+ * As a slibc extension, `errno` is guaranteed not to be set.
*
* @etymology (Free) allocated memory.
*
@@ -277,6 +279,8 @@ void free(void* ptr)
* This function uses variadic arguments because there
* there are multiple conflicting specifications for `cfree`.
*
+ * As a slibc extension, `errno` is guaranteed not to be set.
+ *
* @param ptr Pointer to the beginning of the memory allocation.
* The process may crash if it does not point to the
* beginning of a memory allocation on the heap.
diff --git a/src/slibc-alloc.c b/src/slibc-alloc.c
index 2f51603..f93a4b5 100644
--- a/src/slibc-alloc.c
+++ b/src/slibc-alloc.c
@@ -58,15 +58,19 @@
* This function is identical to `free`, except it is guaranteed not to
* override the memory segment with zeroes before freeing the allocation.
*
+ * `errno` is guaranteed not to be set.
+ *
* @param segment The memory segment to free.
*
* @since Always.
*/
void fast_free(void* segment)
{
+ int saved_errno = errno;
if (segment == NULL)
return;
munmap(PURE_ALLOC(segment), PURE_SIZE(segment));
+ errno = saved_errno;
}
@@ -74,16 +78,20 @@ void fast_free(void* segment)
* This function is identical to `free`, except it is guaranteed to
* override the memory segment with zeroes before freeing the allocation.
*
+ * `errno` is guaranteed not to be set.
+ *
* @param segment The memory segment to free.
*
* @since Always.
*/
void secure_free(void* segment)
{
+ int saved_errno = errno;
if (segment == NULL)
return;
explicit_bzero(PURE_ALLOC(segment), PURE_SIZE(segment));
fast_free(segment);
+ errno = saved_errno;
}