Re: [PATCH] mount: make the --offset option support hex number

[Liu Aleaxander <aleaxander@xxxxxxxxx>]

On Thu, Mar 25, 2010 at 11:39 AM, Américo Wang <xiyou.wangcong@xxxxxxxxx> wrote:
> On Thu, Mar 25, 2010 at 11:17 AM, Liu Aleaxander <aleaxander@xxxxxxxxx> wrote:
>> Hi Yann,
>>
>> On Thu, Mar 25, 2010 at 5:05 AM, Yann Droneaud <yann@xxxxxxxxxxx> wrote:
>>>
>>> Le mercredi 24 mars 2010 à 14:38 +0800, Liu Aleaxander a écrit :
>>>
>>> > +       if (offset) {
>>> > +               int ret = 0;
>>> > +               if (offset[0] == '0' && offset[1] == 'x')
>>> > +                       ret = sscanf(offset, "%llx", &off);
>>> > +               else
>>> > +                       ret = sscanf(offset, "%llu", &off);
>>> > +               if (ret != 1)
>>> > +                       usage();
>>> > +       }
>>> >
>>>
>>> Why not using strtoull(), which handle decimal, hexadecimal and octal
>>> for free ?
>>>
>>
>> Thanks for your good point. But I found that the strtoull can't
>> recognize  the difference between non-digit case  and zero number
>> case, since it will both returns 0.
>
> This is exactly why you should check the second value-result parameter
> of strtoul().
>

Hi  Américo,

Thanks for your advice. Here is the new patch.

---------
>From 78407cf1e1382b564bd0cc9df169accbfb1de7a0 Mon Sep 17 00:00:00 2001
From: Liu Aleaxander <Aleaxander@xxxxxxxxx>
Date: Thu, 25 Mar 2010 13:11:56 +0800
Subject: [PATCH] mount: make the --offset option support hex number

Sometimes the hex number makes more sense.
Version 2, use the strtoull to handle the hex number case.

Signed-off-by: Liu Aleaxander <Aleaxander@xxxxxxxxx>
---
 mount/lomount.c |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/mount/lomount.c b/mount/lomount.c
index 67712c6..8ee7fad 100644
--- a/mount/lomount.c
+++ b/mount/lomount.c
@@ -1015,8 +1015,14 @@ main(int argc, char **argv) {
                        usage();
        }

-       if (offset && sscanf(offset, "%llu", &off) != 1)
-               usage();
+       if (offset) {
+               char *end;
+               off = strtoull(offset, &end, 0);
+               if (*end) {
+                       fprintf(stderr, _("%s is not a valid
number\n"), offset);
+                       return -1;
+               }
+       }

        if (sizelimit && sscanf(sizelimit, "%llu", &slimit) != 1)
                usage();
-- 
1.6.0.2


-- 
regards
Liu Aleaxander
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