terminatorlib.freebsd — terminatorlib 0.98 documentation

# Source code for terminatorlib.freebsd

    #!/usr/bin/python
    #
    # Copyright (c) 2008, Thomas Hurst <tom@hur.st>
    #
    # Use of this file is unrestricted provided this notice is retained.
    # If you use it, it'd be nice if you dropped me a note.  Also beer.

    """
     freebsd.get_process_cwd(pid):
      Use sysctl() to retrieve the cwd of an arbitrary process on FreeBSD
      using kern.proc.filedesc, as used by procstat(1).
      Tested on FreeBSD 7-STABLE/amd64 from April 11 2008.
    """

    from ctypes import *

    class sockaddr_storage(Structure):
      """struct sockaddr_storage, defined in /usr/include/sys/socket.h"""
      _fields_ = [
        ('ss_len',     c_char),
        ('ss_family',  c_char),       # /usr/include/sys/_types.h; _uint8_t
        ('__ss_pad1',  c_char * 6),   # (sizeof(int64) - sizeof(char) - sizeof(ss_family_t))
        ('__ss_align', c_longlong),
        ('__ss_pad2',  c_char * 112), # (128(maxsize) - sizeof(char) - sizeof(ss_family_t) -
                                      # sizeof(ss_pad1) - sizeof(int64))
      ]

    class kinfo_file(Structure):
      """struct kinfo_file, defined in /usr/include/sys/user.h """
      _fields_ = [
          ('kf_structsize',    c_int),
          ('kf_type',          c_int),
          ('kf_fd',            c_int),
          ('kf_ref_count',     c_int),
          ('kf_flags',         c_int),
          ('kf_offset',        c_size_t), # this is a off_t, a pointer
          ('kf_vnode_type',    c_int),
          ('kf_sock_domain',   c_int),
          ('kf_sock_type',     c_int),
          ('kf_sock_protocol', c_int),
          ('kf_path',          c_char * 1024), # PATH_MAX
          ('kf_sa_local',      sockaddr_storage),
          ('kf_sa_peer',       sockaddr_storage),
      ]

    libc = CDLL('libc.so.7')

    uintlen = c_size_t(sizeof(c_uint))
    ver = c_uint(0)

    if (libc.sysctlbyname('kern.osreldate', byref(ver), byref(uintlen), None, 0) < 0):
      raise OSError, "sysctlbyname returned < 0"

    # kern.proc.filedesc added for procstat(1) after these __FreeBSD_versions
    if ver.value < 700104 and ver.value < 800019:
      raise NotImplementedError, "cwd detection requires a recent 7.0-STABLE or 8-CURRENT"

    def get_process_cwd(pid):
      """Return string containing the current working directory of the given pid,
         or None on failure."""
      # /usr/include/sys/sysctl.h
      # CTL_KERN, KERN_PROC, KERN_PROC_FILEDESC
      oid = (c_uint * 4)(1, 14, 14, pid)

      if libc.sysctl(oid, 4, None, byref(uintlen), None, 0) < 0:
        return None

      buf = c_char_p(" " * uintlen.value)
      if libc.sysctl(oid, 4, buf, byref(uintlen), None, 0) < 0:
        return None

      kifs = cast(buf, POINTER(kinfo_file))
      for i in xrange(0, uintlen.value / sizeof(kinfo_file)):
        kif = kifs[i]
        if kif.kf_fd == -1: # KF_FD_TYPE_CWD
          return kif.kf_path

    if __name__ == '__main__':
      import os, sys
      print " => %d cwd = %s" % (os.getpid(), get_process_cwd(os.getpid()))
      for pid in sys.argv:
        try:
          pid = int(pid)
        except:
          pass
        else:
          print " => %d cwd = %s" % (pid, get_process_cwd(pid))