Re: /kern/file.c BUG

["Vesa Jääskeläinen" <chaac@nic.fi>]

Robert Millan wrote:
> On Wed, Jan 23, 2008 at 11:00:57PM +0000, Oleg Strikov wrote:
>> Incorrect behavior of grub_file_open () function in e.g. loop context:
>>
>> char *file_names[] =
>> {
>> "(hd0,1)/file1", //file do not exist
>> "(hd0,1)/file2"  //file exist
>> };
>> grub_file_t file;
>> int i;
>> for (i = 0; i < 2; i++)
>> {
>>      file  = grub_file_open (file_names[i]);
>>      if (file) {...}
>> }
>>
>> There, we should get positive return in the second case (i == 1), but
>> grub_file_open() returns 0.
>>
>> Using gdb i've found that this problem connected with incorrect errno check
>> in /kern/file.c
>>
>> Let's look:
>>
>>> grub_file_t
>>> grub_file_open (const char *name)
>>> {
>>>  grub_device_t device;
>>>  grub_file_t file = 0;
>>>  char *device_name;
>>>  char *file_name;
>>>  device_name = grub_file_get_device_name (name);
>>>  if (grub_errno)
>>>    return 0;
>> But, we DO NOT set grub_errno to 0 at the begining of the function, thats
>> why next loop round it always returns 0
> 
> Fixed, thank you.

Now you broke it ;)

Previous behavior was working correctly. You have to handle errorcodes 
at some point and that means when error is handled it is zeroed (or 
GRUB_ERR_NONE). So code is in callee where that loop was.