[Libguestfs] [PATCH] mllib: Getopt: fix integer parsing

[Richard W.M. Jones]

On Mon, Jul 18, 2016 at 10:13:30AM +0200, Pino Toscano wrote:
> Since we are using gnulib already, make use of xstrtol to parse the
> integer arguments to avoid extra suffixes, etc.
> 
> Fixes commit 0f7bf8f714898c606e5d5015fff5b7803dcd1aee.
> ---
>  mllib/getopt-c.c | 34 ++++++++++++++++++++++++----------
>  1 file changed, 24 insertions(+), 10 deletions(-)
> 
> diff --git a/mllib/getopt-c.c b/mllib/getopt-c.c
> index 1f129a7..2d3f9b6 100644
> --- a/mllib/getopt-c.c
> +++ b/mllib/getopt-c.c
> @@ -30,6 +30,8 @@
>  #include <error.h>
>  #include <assert.h>
>  
> +#include "xstrtol.h"
> +
>  #include <caml/alloc.h>
>  #include <caml/fail.h>
>  #include <caml/memory.h>
> @@ -117,6 +119,26 @@ do_call1 (value funv, value paramv)
>    CAMLreturn0;
>  }

This function needs to return something other than 'int', since on 64
bit OCaml integers (the final destination) are signed 63 bits.  I
think returning 'long' is a better idea, and the receiving 'num'
should also be 'long' (as in my patch).

> +static int
> +strtoint (const char *arg)
> +{
> +  long int num;
> +
> +  if (xstrtol (arg, NULL, 0, &num, NULL) != LONGINT_OK) {
> +    fprintf (stderr, _("%s: '%s' is not a numeric value.\n"),
> +             guestfs_int_program_name, arg);
> +    show_error (EXIT_FAILURE);
> +  }
> +
> +  if (num <= INT_MIN || num >= INT_MAX) {
> +    fprintf (stderr, _("%s: %s: integer out of range\n"),
> +             guestfs_int_program_name, arg);
> +    show_error (EXIT_FAILURE);

These bounds are not tight enough.  On 32 bit they should check the
range of a 31 bit signed int, and on 64 bit, a 63 bit signed int.

Rich.

> +  }
> +
> +  return (int) num;
> +}
> +
>  value
>  guestfs_int_mllib_getopt_parse (value argsv, value specsv, value anon_funv, value usage_msgv)
>  {
> @@ -274,21 +296,13 @@ guestfs_int_mllib_getopt_parse (value argsv, value specsv, value anon_funv, valu
>        break;
>  
>      case 5:  /* Int of string * (int -> unit) */
> -      if (sscanf (optarg, "%d", &num) != 1) {
> -        fprintf (stderr, _("'%s' is not a numeric value.\n"),
> -                 guestfs_int_program_name);
> -        show_error (EXIT_FAILURE);
> -      }
> +      num = strtoint (optarg);
>        v = Field (actionv, 1);
>        do_call1 (v, Val_int (num));
>        break;
>  
>      case 6:  /* Set_int of string * int ref */
> -      if (sscanf (optarg, "%d", &num) != 1) {
> -        fprintf (stderr, _("'%s' is not a numeric value.\n"),
> -                 guestfs_int_program_name);
> -        show_error (EXIT_FAILURE);
> -      }
> +      num = strtoint (optarg);
>        caml_modify (&Field (Field (actionv, 1), 0), Val_int (num));
>        break;
>  
> -- 
> 2.7.4
> 
> _______________________________________________
> Libguestfs mailing list
> Libguestfs at redhat.com
> https://www.redhat.com/mailman/listinfo/libguestfs

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine.  Supports Linux and Windows.
http://people.redhat.com/~rjones/virt-df/