From c2287ba2cff59a50848151833404bce0e3cf0a70 Mon Sep 17 00:00:00 2001 From: Sebastian Huber Date: Tue, 10 Mar 2020 17:07:19 +0100 Subject: libio: Robust file descriptor reference counting There was a race conditon in the reference counting of file descriptors during a close() operation. After the call to the close handler, the rtems_libio_free() function cleared the flags to zero. However, at this point in time there may still exist some holders of the file descriptor. With RTEMS_DEBUG enabled this could lead to failed assertions in rtems_libio_iop_drop(). Change the code to use only atomic read-modify-write operations on the rtems_libio_iop::flags. --- cpukit/include/rtems/libio_.h | 24 +----------------------- 1 file changed, 1 insertion(+), 23 deletions(-) (limited to 'cpukit/include/rtems/libio_.h') diff --git a/cpukit/include/rtems/libio_.h b/cpukit/include/rtems/libio_.h index 916ba85b31..e9eb46263e 100644 --- a/cpukit/include/rtems/libio_.h +++ b/cpukit/include/rtems/libio_.h @@ -84,28 +84,6 @@ extern rtems_filesystem_mount_table_entry_t rtems_filesystem_null_mt_entry; */ extern rtems_filesystem_global_location_t rtems_filesystem_global_location_null; -/** - * @brief Sets the iop flags to the specified flags together with - * LIBIO_FLAGS_OPEN. - * - * Use this once a file descriptor allocated via rtems_libio_allocate() is - * fully initialized. - * - * @param[in] iop The iop. - * @param[in] flags The flags. - */ -static inline void rtems_libio_iop_flags_initialize( - rtems_libio_t *iop, - uint32_t flags -) -{ - _Atomic_Store_uint( - &iop->flags, - LIBIO_FLAGS_OPEN | flags, - ATOMIC_ORDER_RELEASE - ); -} - /** * @brief Sets the specified flags in the iop. * @@ -222,7 +200,7 @@ static inline void rtems_libio_iop_drop( rtems_libio_t *iop ) #define rtems_libio_check_is_open(_iop) \ do { \ - if (((_iop)->flags & LIBIO_FLAGS_OPEN) == 0) { \ + if ((rtems_libio_iop_flags(_iop) & LIBIO_FLAGS_OPEN) == 0) { \ errno = EBADF; \ return -1; \ } \ -- cgit v1.2.3