What library routines and header files have changed to support ELF?
We changed the nlist() routine to handle 32-bit ELF, 64-bit ELF and a.out format files. It now uses file mapping to read symbol tables and string tables. Since there can be confusion about whether a symbol needs to be prepended with an underscore, nlist() checks for the requested symbol with or without its prepended underscore. The nlist structure itself did not change for ELF, although ELF’s symbols look nothing like nlist records. Since ELF programs put their user stack in a different location from a.out programs, we had to change the -lkvm library to look for each process’s stack at a location specific to that process, and to avoid making assumptions about the layout of the process. The headers
