Re: [PATCH 4/5 v2] set: check seek success

[Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>]

On 11/10/2014 01:51 AM, Thierry Reding wrote:
> On Sat, Nov 08, 2014 at 11:14:09PM +0100, Patrick Georgi wrote:
>> This could silently fail which leads to surprising behaviour.
>>
>> Found-by: Coverity Scan
>> Signed-off-by: Patrick Georgi <patrick-U1IrdZU7gScKt1dFYRw6Gg@public.gmane.org>
>> ---
>>   src/set.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/set.c b/src/set.c
>> index ff32b53..907d640 100644
>> --- a/src/set.c
>> +++ b/src/set.c
>> @@ -59,7 +59,11 @@ read_from_image(char	*filename,
>>   		return result;
>>   	}
>>
>> -	fseek(fp, offset, SEEK_SET);
>> +	if (fseek(fp, offset, SEEK_SET) == -1) {
>> +		printf("Error: Couldn't seek to %s(%d)\n", filename, offset);
>
> offset is unsigned, so the format specifier should be %u. I also wonder
> whether it would be good to output errno along with the message (or the
> string representation thereof) to increase the information content. But
> given that none of the other error messages have that it could be a
> separate patch.

Using perror() might be useful?