def Start(self):
"""Start this process with fork(), haandling redirects."""
# TODO: If OSH were a job control shell, we might need to call some of
# these here. They control the distribution of signals, some of which
# originate from a terminal. All the processes in a pipeline should be in
# a single process group.
#
# - posix.setpgid()
# - posix.setpgrp()
# - posix.tcsetpgrp()
#
# NOTE: posix.setsid() isn't called by the shell; it's should be called by the
# login program that starts the shell.
#
# The whole job control mechanism is complicated and hacky.
pid = posix.fork()
if pid < 0:
# When does this happen?
raise RuntimeError('Fatal error in posix.fork()')
elif pid == 0: # child
SignalState_AfterForkingChild()
# This doesn't make the child respond to Ctrl-Z? Why not? Is there
# something at the Python level? signalmodule.c has PyOS_AfterFork but
# it seems OK.
# If we add it then somehow the process stop responding to Ctrl-C too.
#signal.signal(signal.SIGTSTP, signal.SIG_DFL)
for st in self.state_changes:
st.Apply()
self.thunk.Run()
# Never returns
#log('STARTED process %s, pid = %d', self, pid)
# Invariant, after the process is started, it stores its PID.
self.pid = pid
return pid
def Start(self, why):
# type: (trace_t) -> int
"""Start this process with fork(), handling redirects."""
# TODO: If OSH were a job control shell, we might need to call some of
# these here. They control the distribution of signals, some of which
# originate from a terminal. All the processes in a pipeline should be in
# a single process group.
#
# - posix.setpgid()
# - posix.setpgrp()
# - posix.tcsetpgrp()
#
# NOTE: posix.setsid() isn't called by the shell; it's should be called by the
# login program that starts the shell.
#
# The whole job control mechanism is complicated and hacky.
pid = posix.fork()
if pid < 0:
# When does this happen?
raise RuntimeError('Fatal error in posix.fork()')
elif pid == 0: # child
pyos.SignalState_AfterForkingChild()
for st in self.state_changes:
st.Apply()
self.tracer.SetProcess(posix.getpid())
self.thunk.Run()
# Never returns
#log('STARTED process %s, pid = %d', self, pid)
self.tracer.OnProcessStart(pid, why)
# Class invariant: after the process is started, it stores its PID.
self.pid = pid
# Program invariant: We keep track of every child process!
self.job_state.AddChildProcess(pid, self)
return pid