I want to provide a appending functionality in a
character device driver and I have done the following
thing in a device_open function.
if (pfile->f_flags & O_APPEND)
{
// Opening a device file in Append Mode.
printk("<1> Append Flag has been Used\n");
pfile->f_pos = pdevice_data->size;
}
else if ((pfile->f_flags & O_ACCMODE) == O_WRONLY)
{
// Opening a device file in Write Mode
if (pdevice_data->data)
{
kfree(pdevice_data->data);
pdevice_data->data = NULL;
pdevice_data->size = 0;
}
}
In this , pdevice_data is a pointer to Device_Data
structure which is defined as follows:
typedef struct Device_Data {
void * data;
unsigned long size;
unsigned long max_size;
}Device_Data;
Is my approach fine and is it fine If I modify on my
own pfile->f_pos in the device_open ?
Is there any way by which Kernel takes cares of this
on its own and set the file position at the end of the
file when I use the following commmand
cat >> /dev/CharDev0
Regards
Dinesh
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