Re: [PATCH]Modify do_exec() handler to deal with multiple imgact handlers

On Tuesday, September 02, 2014 03:59:17 PM Sean Bruno wrote:
> https://reviews.freebsd.org/D696
> 
> I found that the binmisc handler was not executing if the shell handler
> fired.  Both were using the same intepreted flag to determine if they
> should run.
> 
> This change modifies struct image_params.interpreted to be a bitfield
> instead of a bool flag and assigns one bit to each image activator.
> 
> Comments?
> 
> sean
> 
> Index: sys/kern/imgact_binmisc.c
> ===================================================================
> --- sys/kern/imgact_binmisc.c
> +++ sys/kern/imgact_binmisc.c
> _at__at_ -600,12 +600,12 _at__at_
>  	}
> 
>  	/* No interpreter nesting allowed. */
> -	if (imgp->interpreted) {
> +	if (imgp->interpreted & IMGACT_BINMISC) {
>  		mtx_unlock(&interp_list_mtx);
>  		return (ENOEXEC);
>  	}
> 
> -	imgp->interpreted = 1;
> +	imgp->interpreted |= IMGACT_BINMISC;
> 
>  	if (imgp->args->fname != NULL) {
>  		fname = imgp->args->fname;
> Index: sys/kern/imgact_shell.c
> ===================================================================
> --- sys/kern/imgact_shell.c
> +++ sys/kern/imgact_shell.c
> _at__at_ -115,10 +115,10 _at__at_
>  	 * Don't allow a shell script to be the shell for a shell
>  	 *	script. :-)
>  	 */
> -	if (imgp->interpreted)
> +	if (imgp->interpreted & IMGACT_SHELL)
>  		return (ENOEXEC);
> 
> -	imgp->interpreted = 1;
> +	imgp->interpreted |= IMGACT_SHELL;
> 
>  	/*
>  	 * At this point we have the first page of the file mapped.
> Index: sys/sys/imgact.h
> ===================================================================
> --- sys/sys/imgact.h
> +++ sys/sys/imgact.h
> _at__at_ -61,7 +61,9 _at__at_
>  	unsigned long entry_addr; /* entry address of target executable */
>  	unsigned long reloc_base; /* load address of image */
>  	char vmspace_destroyed;	/* flag - we've blown away original vm space */
> -	char interpreted;	/* flag - this executable is interpreted */
> +#define IMGACT_SHELL	0x1
> +#define IMGACT_BINMISC	0x2
> +	unsigned char interpreted;	/* mask of interpretes that have run */

s/interpretes/interpreters/

Other than that I think this is fine, though I wonder if it will result
in some unexpected effects (you probably want to be able to use a binmisc
binary as the #! interpreter for a script, but I'm not sure the opposite
is true.

-- 
John Baldwin