def posix_spawnp(filename, args, fileactions=None, env=None):
"""Invoke posix_spawnp(3C).
'filename' is the name of the executeable file.
'args' is a sequence of arguments supplied to the newly executed program.
'fileactions' defines what actions will be performed upon the file
descriptors of the spawned executable. If defined, it must be a
SpawnFileAction object.
'env', the enviroment, if provided, it must be a sequence object."""
if not isinstance(filename, six.string_types):
raise TypeError("filename must be a string")
pid = ffi.new("pid_t *")
spawn_args = []
# This essentially does force_bytes in pkg.misc, but importing pkg.misc has
# a circular import issue, so we implement the conversion here.
for arg in args:
if six.PY3 and isinstance(arg, six.string_types):
arg = arg.encode()
spawn_args.append(ffi.new("char []", arg))
spawn_args.append(ffi.NULL)
# Process env, if supplied by caller
spawn_env = []
if env:
for arg in env:
try:
if six.PY3 and isinstance(arg, six.string_types):
arg = arg.encode()
spawn_env.append(ffi.new("char []", arg))
except:
# If an environment variable cannot be added for any reason,
# just continue. (Most likely is UnicodeEncodeError)
pass
spawn_env.append(ffi.NULL)
# setup file actions, if passed by caller
s_action = ffi.NULL
if fileactions:
if not isinstance(fileactions, SpawnFileAction):
raise TypeError("fileact must be a SpawnFileAction object.")
s_action = fileactions.fa
# Now do the actual spawn
rc = lib.posix_spawnp(pid, filename.encode(), s_action, ffi.NULL,
spawn_args, spawn_env)
_check_error(rc)
return pid[0]
def __init__(self):
self.fa = ffi.new("posix_spawn_file_actions_t *")
rc = lib.posix_spawn_file_actions_init(self.fa)
self.fa = ffi.gc(self.fa, lib.posix_spawn_file_actions_destroy)
# The file_actions routines don't set errno, so we have to create
# the exception tuple by hand.
_check_error(rc)
def add_close_childfds(self, start_fd, except_fd=-1):
"""Add to a SpawnFileAction a series of 'closes' that will close all of
the fds >= startfd in the child process. A single fd may be skipped,
provided that it is given as the optional except argument."""
if not isinstance(start_fd, int):
raise TypeError("start_fd must be int type")
if not isinstance(except_fd, int):
raise TypeError("except_fd must be int type")
# Set up walk_data for fdwalk.
wd = ffi.new("walk_data *", [0])
wd.skip_fd = ffi.cast("int", except_fd)
wd.start_fd = ffi.cast("int", start_fd)
wd.fap = self.fa
# Perform the walk.
lib.fdwalk(walk_func, wd)
