Re: [PATCH] Adding three new function attributes for static analysis of file descriptors

[David Malcolm <dmalcolm@redhat.com>]

On Wed, 2022-07-20 at 23:29 +0530, Immad Mir wrote:


> This patch adds three new function attributes to GCC that
> are used for static analysis of usage of file descriptors:

Thanks for the updated patch.

Some very minor spelling/grammar/whitespace nits...

> 
> 1) __attribute__ ((fd_arg(N))): The attributes may be applied to a function that
> takes on open file descriptor at refrenced argument N.

"on open" -> "an open"

"refrenced" -> "referenced"

[...snip...]

> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index d5ff1018372..9234275ca6d 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -9843,7 +9843,12 @@ This warning requires @option{-fanalyzer}, which enables it; use
>  to disable it.
>  
>  This diagnostic warns for paths through code in which a 
> -@code{read} on a write-only file descriptor is attempted, or vice versa
> +@code{read} on a write-only file descriptor is attempted, or vice versa.
> +
> +This diagnostic also warns for code paths in a which a function with attribute
> +@code{fd_arg_read (N)} is called with a file descriptor opened with @code{O_WRONLY} 
> +at refrenced argument @code{N} or a function with attribute @code{fd_arg_write (N)}

"refrenced" -> "referenced"

> +is called with a file descriptor opened with @code{O_RDONLY} at refrenced argument @var{N},

"refrenced" -> "referenced".

Please wrap these lines to avoid going over 80 columns.

>  
>  @item -Wno-analyzer-fd-double-close
>  @opindex Wanalyzer-fd-double-close
> @@ -9875,6 +9880,11 @@ to disable it.
>  This diagnostic warns for paths through code in which a 
>  read or write is called on a closed file descriptor.
>  
> +This diagnostic also warns for paths through code in which
> +a function with attribute @code{fd_arg (N)} or @code{fd_arg_read (N)}
> +or @code{fd_arg_write (N)} is called with a closed file descriptor at
> +refrenced argument @code{N}.

"refrenced" -> "referenced".


> +
>  @item -Wno-analyzer-fd-use-without-check
>  @opindex Wanalyzer-fd-use-without-check
>  @opindex Wno-analyzer-fd-use-without-check
> @@ -9885,6 +9895,11 @@ to disable it.
>  This diagnostic warns for paths through code in which a 
>  file descriptor is used without being checked for validity.
>  
> +This diagnostic also warns for paths through code in which
> +a function with attribute @code{fd_arg (N)} or @code{fd_arg_read (N)}
> +or @code{fd_arg_write (N)} is called with a file descriptor, at refrenced
> +argument @code{N}, without being checked for validity.

"refrenced" -> "referenced".

> +
>  @item -Wno-analyzer-file-leak
>  @opindex Wanalyzer-file-leak
>  @opindex Wno-analyzer-file-leak

[...snip...]

...but with those fixed, this patch is OK for trunk, assuming it
bootstraps and passes regression tests.

Thanks!
Dave