kcynic
November 4th, 2008, 09:22 PM
I want to write a disk filter driver which can decrypt some special cdrom on fly. You might ask me why i need a disk filter but not a file system filter driver?
The answer is that, if i use file system filter driver, i'll have to set a completion routine in my filter's IRP_MJ_READ routine, so, the routine might be easy to be hooked by a third-party filter. In addition, if i use a disk filter other than fs filter, the driver would be more convenient to extend, right?
I have seen such a disk filter driver do some similar task with me, but i have no source code of it and can't modify it to fit my requirement. Because it's a disk driver, so it will not receive IRP_MJ_READ irp when the user app call ReadFile to read data from the disc. So, where and when i can set a completion routine to hold the data read from the disc by the lower disk driver? In the DriverEntry or anywhere else?
Thanks.
The answer is that, if i use file system filter driver, i'll have to set a completion routine in my filter's IRP_MJ_READ routine, so, the routine might be easy to be hooked by a third-party filter. In addition, if i use a disk filter other than fs filter, the driver would be more convenient to extend, right?
I have seen such a disk filter driver do some similar task with me, but i have no source code of it and can't modify it to fit my requirement. Because it's a disk driver, so it will not receive IRP_MJ_READ irp when the user app call ReadFile to read data from the disc. So, where and when i can set a completion routine to hold the data read from the disc by the lower disk driver? In the DriverEntry or anywhere else?
Thanks.