I've been recovering a hard disk using dd_rescue, which provides me a list of all of the device sectors it could not copy due to hardware errors.
I'd like to take that list, and write a tool to give me all of the files that contain these bad sectors so I can delete them. I'm not sure what APIs I can use to do this--essentially i want to get a list of all files on disk and for each file, a list of the ranges of sectors it occupies on disk.
My first guess is that I will iterate over each directory entry on the disk and check to see if the file overlaps one of these bad sectors. Maybe there's a better way.
If you want to map a file's data location to a physical block (sector), you can use the fcntl(2) call with the F_LOG2PHYS command. Not all file systems support this command, but HFS+ does. Just use lseek to pick the file offset and you can get back the diskoffset from F_LOG2PHYS (it's returned in a struct log2phys in the l2p_devoffset field). See fcntl.h for more details.