[PATCH 2/2] not-cancel.h: Support testing fortify build with Clang

[Sam James]

"H.J. Lu" <hjl.tools@gmail.com> writes:

> When Clang is used to test fortify glibc build configured with
>
> --enable-fortify-source=N
>
> clang issues errors like
>
> In file included from tst-rfc3484.c:60:
> In file included from ./getaddrinfo.c:81:
> ../sysdeps/unix/sysv/linux/not-cancel.h:36:10: error: reference to overloaded function could not be resolved; did you mean to call it?
>    36 | __typeof (open64) __open64_nocancel;
>       |          ^~~~~~~~
> ../include/bits/../../io/bits/fcntl2.h:127:1: note: possible target for call
>   127 | open64 (__fortify_clang_overload_arg (const char *, ,__path), int __oflag,
>       | ^
> ../include/bits/../../io/bits/fcntl2.h:118:1: note: possible target for call
>   118 | open64 (__fortify_clang_overload_arg (const char *, ,__path), int __oflag)
>       | ^
> ../include/bits/../../io/bits/fcntl2.h:114:1: note: possible target for call
>   114 | open64 (const char *__path, int __oflag, mode_t __mode, ...)
>       | ^
> ../io/fcntl.h:219:12: note: possible target for call
>   219 | extern int open64 (const char *__file, int __oflag, ...) __nonnull ((1));
>       |            ^
>
> because clang fortify support for functions with variable arguments relies
> on function overload.  Update not-cancel.h to avoid __typeof on functions
> with variable arguments.
>
> Co-Authored-By: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
> ---
>  sysdeps/unix/sysv/linux/not-cancel.h | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/sysdeps/unix/sysv/linux/not-cancel.h b/sysdeps/unix/sysv/linux/not-cancel.h
> index 62363c1b0f..ece329711b 100644
> --- a/sysdeps/unix/sysv/linux/not-cancel.h
> +++ b/sysdeps/unix/sysv/linux/not-cancel.h
> @@ -30,16 +30,16 @@
>  #include <sys/random.h>
>  
>  /* Non cancellable open syscall.  */
> -__typeof (open) __open_nocancel;
> +extern int __open_nocancel (const char *, int, ...);
>  
>  /* Non cancellable open syscall (LFS version).  */
> -__typeof (open64) __open64_nocancel;
> +extern int __open64_nocancel (const char *, int, ...);
>  
>  /* Non cancellable openat syscall.  */
> -__typeof (openat) __openat_nocancel;
> +extern int __openat_nocancel (int fd, const char *, int, ...);
>  
>  /* Non cacellable openat syscall (LFS version).  */
> -__typeof (openat64) __openat64_nocancel;
> +extern int __openat64_nocancel (int fd, const char *, int, ...);
>  
>  /* Non cancellable read syscall.  */
>  __typeof (__read) __read_nocancel;
> @@ -54,7 +54,7 @@ __typeof (__write) __write_nocancel;
>  __typeof (__close) __close_nocancel;
>  
>  /* Uncancelable fcntl.  */

Typo: Non cancellable. I will fix it once you merge this to avoid
conflicts.

> -__typeof (__fcntl) __fcntl64_nocancel;
> +int __fcntl64_nocancel (int, int, ...);
>  
>  #if IS_IN (libc) || IS_IN (rtld)
>  hidden_proto (__open_nocancel)

Reviewed-by: Sam James <sam@gentoo.org>

It would be nice if Clang had a way around this, but whatever.