This change introduce 2 items:
1. If the size of the space requested is 0, the behavior is implementation-defined:
either a null pointer shall be returned, or the behavior shall be as if the size
were some non-zero value, except that the behavior is undefined if the returned
pointer is used to access an object.
Change the behavior to be similar to Linux and Android and allocates an object
of a minimum size instead of returning null pointer.
https://pubs.opengroup.org/onlinepubs/9699919799/functions/malloc.htmlhttps://pubs.opengroup.org/onlinepubs/9699919799/functions/calloc.htmlhttps://pubs.opengroup.org/onlinepubs/9699919799/functions/realloc.html
2. The description of realloc() has been modified from previous versions of this
standard to align with the ISO/IEC 9899:1999 standard. Previous versions explicitly
permitted a call to realloc (p, 0) to free the space pointed to by p and return
a null pointer. While this behavior could be interpreted as permitted by this
version of the standard, the C language committee have indicated that this
interpretation is incorrect. Applications should assume that if realloc() returns
a null pointer, the space pointed to by p has not been freed. Since this could lead
to double-frees, implementations should also set errno if a null pointer actually
indicates a failure, and applications should only free the space if errno was changed.
Do not free memory of zero-length reallocation is requested
https://pubs.opengroup.org/onlinepubs/9699919799/functions/realloc.html
Co-authored-by: fangxinyong <fangxinyong@xiaomi.com>
Signed-off-by: Petro Karashchenko <petro.karashchenko@gmail.com>
since it's useful to redirect these functions to others
sometime(e.g. validate the memory before write).
Change-Id: I6253a9231af8809e8362f4bc5a1bd67fb094c3b0
it's more simple to make mm_heap_s opaque outside of mm
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I5c8e435f6baba6d22b10c5f7e8d9191104fb5af2
The solution is to remove all of the memory management function calls from the interface. Instead, the interface exports the userspace heap structure and then kernel size implementations of those memory management functions will operate on the userspace heap structure. This avoids the unnecessary system calls and, more importantly, failures do to freeing memory when a test exits.
yangyalei