Re: [Qemu-devel] [PATCH 01/16] cutils: tighten qemu_parse_fd()

[Eric Blake <eblake@redhat.com>]

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On 04/10/2014 02:24 AM, Laszlo Ersek wrote:
> qemu_parse_fd() used to handle at least the following strings incorrectly:
> o "-2":         simply let through
> o "2147483648": returned as LONG_MAX==INT_MAX on ILP32 (with ERANGE
>                 ignored); implementation-defined behavior on LP64
> 
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> ---
>  util/cutils.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)

I still think qemu should follow libvirt's lead of wrapping ALL uses of
strto*l behind sane wrappers, since this is not the only place in the
code base affected by misuse of the function - but that's a story for
another day.

>  
> +    errno = 0;
>      fd = strtol(param, &endptr, 10);
> -    if (*endptr || (fd == 0 && param == endptr)) {
> +    if (param == endptr /* no conversion performed */                    ||
> +        errno != 0      /* not representable as long; possibly others */ ||
> +        *endptr != '\0' /* final string not empty */                     ||
> +        fd < 0          /* invalid as file descriptor */                 ||
> +        fd > INT_MAX    /* not representable as int */) {
>          return -1;

Your comments make it particularly obvious that YOU know how to properly
use this function, and hopefully teach future readers. :)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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