TODO.md

To-do list

Completeness/correctness

• Use PTRACE_O_EXITKILL so the tracee process can't escape
• Save/restore more state:
  • Full set of x86 registers
  • Signal handlers and signal mask
  • Opened FDs
  • Futex robust list (not very important)
  • Multiple threads
• Initial stack:
  • Ensure the stack is properly aligned
  • Make the stack bigger
• Check that various inputs are unchanged at restore time:
  • File contents
  • Inode numbers from stat() and fstat()
  • UID, GID, etc.
  • x86 segment selector registers (to be nit-picky)
• Save and replay output to stdout/stderr
• Ensure restore's temporary mapping does not conflict with restored program
• Check that syscalls are for the correct architecture (x86-64 not x86-32)

Usability

• Combine the two dump files into a single file
• Add an argument for the snapshot file; stop hard-coding the filename
• Make ptracer run elf_loader automatically

Efficiency

• Use /proc/$PID/mem to read memory instead of ptrace()
• Don't write zero pages into the snapshot file
• De-duplicate filenames in the snapshot file

Security

• Don't leave the restore program mapped at a fixed address

Features

• Add a tool to examine a snapshot:
  • Print mappings in the format of /proc/$PID/maps
  • Show memory consumption
  • Show what triggered producing the snapshot (e.g. the syscall we didn't handle)