On 3/4/22 01:21, Peter Maydell wrote:
Currently qemu_try_memalign()'s behaviour if asked to allocate 0 bytes is rather variable: * on Windows, we will assert * on POSIX platforms, we get the underlying behaviour of the posix_memalign() or equivalent function, which may be either "return a valid non-NULL pointer" or "return NULL"Explictly check for 0 byte allocations, so we get consistent behaviour across platforms. We handle them by incrementing the size so that we return a valid non-NULL pointer that can later be passed to qemu_vfree(). This is permitted behaviour for the posix_memalign() API and is the most usual way that underlying malloc() etc implementations handle a zero-sized allocation request, because it won't trip up calling code that assumes NULL means an error. (This includes our own qemu_memalign(), which will abort on NULL.) This change is a preparation for sharing the qemu_try_memalign() code between Windows and POSIX. Signed-off-by: Peter Maydell<[email protected]> --- util/oslib-posix.c | 3 +++ util/oslib-win32.c | 4 +++- 2 files changed, 6 insertions(+), 1 deletion(-)
Reviewed-by: Richard Henderson <[email protected]> r~
