[syslinux] COM32

[Mortaza Doulaty]

To be more specific about the error, the file pointer (after trying to
create a new file) is NULL and the error no is: 22 which is 'Invalid
argument'.

I tried reading from a file from the same location, it succeeded.

On Wed, Jun 16, 2010 at 1:54 PM, Mortaza Doulaty
<mortaza.doulaty at gmail.com>wrote:

> Hi,
>
> I've started my sample COM32 module, as the first step, I tried to write to
> a file in bootloader's file system itself.
> When I call this module, the first printf (which prints an initial message
> on the console) works, but it hangs there. No file is created and the
> program seems to hang.
>
> As hpa said, I'm using standard C calls to access to the file system of the
> bootloader itself.
>
> What is wrong with the code?
>
> #include <stdio.h>
> #include <string.h>
> #include <console.h>
>
> int main(int argc, char *argv[])
> {
>     int i;
>
>     openconsole(&dev_stdcon_r, &dev_stdcon_w);
>
>     printf("Hello, World!\n");
>
>     FILE *f;
>
>     f = fopen("./mrt.txt", "wt");
>
>     fprintf(f, "Hello world!");
>
>     fclose(f);
>
>     printf("Writing done!\n");
>
>     return 0;
>
>
> On Wed, Jun 16, 2010 at 12:11 PM, H. Peter Anvin <hpa at zytor.com> wrote:
>
>> On 06/16/2010 12:31 AM, Mortaza Doulaty wrote:
>> > Hi,
>> >
>> > I'm using SYSLINUX as a boot loader to my OS's. Before booting my OS's,
>> I
>> > want to check for existence of some files on my hard drives (NTFS and
>> ext3
>> > as well).
>> > I think using COM32 modules to access to file system. I want some
>> resources
>> > to learn more about COM32 modules and especially accessing file system
>> using
>> > COM32 modules.
>> >
>> > Any help would highly appreciated.
>> >
>>
>> In current versions of Syslinux, COM32 modules (as well as Syslinux
>> proper) can only access the bootloader filesystem itself.  Filesystems
>> on that filesystem can be accessed using normal C calls.  Accessing
>> filesystems on other devices is not supported in the current version of
>> Syslinux (it's targetted for Syslinux 5) but your COM32 module can of
>> course carry its own filesystem access library and access the filesystem
>> that way.  There are open source libraries for a lot of filesystems
>> available, including FAT, NTFS, and ext2/3/4, but it probably will
>> entail some porting effort to make them work in the COM32 environment.
>>
>>        -hpa
>>
>> --
>> H. Peter Anvin, Intel Open Source Technology Center
>> I work for Intel.  I don't speak on their behalf.
>>
>>
>