Why not just set errno to 0 in the success case?
On 04/13/17 17:05, Oriol Arcas wrote:
> Fixes bug #2921.
>
> During odp_shm_reserve() mmap is tried with huge pages, and if it fails,
> without huge pages. The first call leaves errno set, which can confuse
> the client app.
>
> In general, errno must be cleared before calling any library call known
> to set it (see SEI CERT rule ERR30-C).
>
> Signed-off-by: Oriol Arcas <or...@starflownetworks.com>
> ---
> platform/linux-generic/_ishmphy.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/platform/linux-generic/_ishmphy.c
> b/platform/linux-generic/_ishmphy.c
> index d519af6..87c33ef 100644
> --- a/platform/linux-generic/_ishmphy.c
> +++ b/platform/linux-generic/_ishmphy.c
> @@ -121,10 +121,12 @@ void *_odp_ishmphy_map(int fd, void *start, uint64_t
> size,
> * The initial free maping can then be removed.
> */
> mapped_addr = MAP_FAILED;
> + errno = 0;
> mapped_addr_tmp = mmap(NULL, size, PROT_READ | PROT_WRITE,
> MAP_SHARED | mmap_flags, fd, 0);
> if (mapped_addr_tmp != MAP_FAILED) {
> /* If OK, do new map at right fixed location... */
> + errno = 0;
> mapped_addr = mmap(start,
> size, PROT_READ | PROT_WRITE,
> MAP_SHARED | MAP_FIXED | mmap_flags,
> @@ -132,11 +134,13 @@ void *_odp_ishmphy_map(int fd, void *start, uint64_t
> size,
> if (mapped_addr != start)
> ODP_ERR("new map failed:%s\n", strerror(errno));
> /* ... and remove initial mapping: */
> + errno = 0;
> if (munmap(mapped_addr_tmp, size))
> ODP_ERR("munmap failed:%s\n", strerror(errno));
> }
> } else {
> /* just do a new mapping in the VA space: */
> + errno = 0;
> mapped_addr = mmap(NULL, size, PROT_READ | PROT_WRITE,
> MAP_SHARED | mmap_flags, fd, 0);
> if ((mapped_addr >= common_va_address) &&
> @@ -154,6 +158,7 @@ void *_odp_ishmphy_map(int fd, void *start, uint64_t size,
> /* if locking is requested, lock it...*/
> if (flags & _ODP_ISHM_LOCK) {
> if (mlock(mapped_addr, size)) {
> + errno = 0;
> if (munmap(mapped_addr, size))
> ODP_ERR("munmap failed:%s\n", strerror(errno));
> ODP_ERR("mlock failed:%s\n", strerror(errno));
>
