Re: [Qemu-devel] [Qemu-block] [PATCH 2/3] qemu-io: Check for trailing chars

[Eric Blake <eblake@redhat.com>]

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On 10/26/2015 04:44 PM, Eric Blake wrote:
> On 10/26/2015 04:06 PM, John Snow wrote:
>> Make sure there's not trailing garbage, e.g.
>> "64k-whatever-i-want-here"
>>
>> Reported-by: Max Reitz <mreitz@redhat.com>
>> Signed-off-by: John Snow <jsnow@redhat.com>
>> ---
>>  qemu-io-cmds.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)

>> +    ret = qemu_strtosz_suffix(s, &end, QEMU_STRTOSZ_DEFSUFFIX_B);
>> +    if (*end != '\0') {
>> +        /* Detritus at the end of the string */
>> +        return -EINVAL;
>> +    }
>> +    return ret;
>>  }
> 
> Eww.  This mixes up two return types, negative errno, and negative
> input.  User input of -22 shouldn't behave differently than -21, just
> because it happens to match -EINVAL.
> 
> Do we ever want to allow a negative return from cvtnum(), or should we
> just blindly map a negative int64_t into -ERANGE for a contract that we
> only accept 63-bit numbers?

Uggh. Maybe I should read qemu_strtosz_suffix() before making bogus
claims (and assuming that it is merely sugar for strtoll).

I stand corrected - the only time you return negative values is if
qemu_strtosz_suffx() populated an errno.

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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