fix: potential security issues - #49

…`ip_info.c`

⏺ Fixed ip_info.c:204 by:
  1. Bounding the sscanf %s with a width specifier (%IF_NAMESIZE s via stringification macros).
  2. Enlarging the local iface buffer to IF_NAMESIZE + 1 so the width-bounded write + null terminator fits safely.
  3. Replacing strcpy(interface, iface) with a bounded strncpy + explicit null-termination, since the caller-provided interface buffer
  is IF_NAMESIZE.

… cross-platform compatibility in `timing.c`.

…nd` in file locking logic.

Instead of calling freopen(tmp_fname, "w", fh) — which re-resolves the path
  and could open a different file than the one we stat'd and locked — we now truncate the already-locked file descriptor directly via
  ftruncate(fileno(fh), 0) and rewind. The operation now targets the same inode we hold the exclusive flock on, so a path swap between
  check and use can no longer redirect the write.