[test] Preparing for job control and signal changes

- demo: How to handle SIGINT in Python
- test/stateful: Repro of issue #1005
  - But I want to fix the issue where Ctrl-Z is ignored first ...
- Rename devtools/sigparse.sh -> test/signal-state.sh
- Start test/group-session.sh

core/pyos.py

@@ -271,6 +271,11 @@ def __call__(self, sig_num, unused_frame):
 def SignalState_AfterForkingChild():
   # type: () -> None
   """Not a member of SignalState since we didn't do dependency injection."""
+
+  # Note: this happens in BOTH interactive and non-interactive shells.
+  # We technically don't need to do most of it in non-interactive, since we
+  # did not change state in InitInteractiveShell().
+
   # Python sets SIGPIPE handler to SIG_IGN by default.  Child processes
   # shouldn't have this.
   # https://docs.python.org/2/library/signal.html

demo/py_signals.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python2
+"""
+py_signals.py
+"""
+from __future__ import print_function
+
+import signal
+import sys
+import time
+
+
+
+g_sigint = False
+
+def SigInt(x, y):
+  print('SIGINT')
+  global g_sigint
+  g_sigint = True
+
+
+def main(argv):
+
+  # This suppresses KeyboardInterrupt.  You can still do Ctrl-\ or check a flag
+  # and throw your own exception.
+  signal.signal(signal.SIGINT, SigInt)
+
+  while True:
+    print('----')
+    time.sleep(0.5)
+    if g_sigint:
+      raise Exception('interrupted')
+
+
+if __name__ == '__main__':
+  try:
+    main(sys.argv)
+  except RuntimeError as e:
+    print('FATAL: %s' % e, file=sys.stderr)
+    sys.exit(1)

spec/stateful/job_control.py

@@ -148,26 +148,13 @@ def bug_1005(sh):
 
   expect_prompt(sh)
 
-  return
-
   sh.sendline('sleep 10')
 
-  # This is NOT right.  The Ctrl-Z goes to the TERMINAL, and the TERMINAL sends
-  # it to both the shell process and the sleep process.  The shell process
-  # should ignore it.
-
-  # Section 19.6 of APUE: SIGTSTP can't be delivered to a process!!
-  # Section 19.7: Signal generation with ioctl TIOCSIG!
-
-  #sh.kill(signal.SIGTSTP)
+  time.sleep(0.1)
 
-  # This distribute Ctrl-Z to the whole process group?  Why doesn't it work?
-  sh.sendcontrol('z')
+  ctrl_z(sh)
   sh.expect(r'.*Stopped.*')
 
-  #sh.expect(r'\^Z')
-
-  return
   sh.sendline('wait')
   sh.sendline('echo status=$?')
   sh.expect(r"status=0")

test/group-session.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+#
+# Test kernel state: the process group and session leader.
+#
+# Usage:
+#   ./group-session.sh <function name>
+
+set -o nounset
+set -o pipefail
+set -o errexit
+
+show() {
+  # by deafult, it shows processes that use the same terminal
+  ps -o pid,ppid,pgid,sid,tname,comm
+}
+
+"$@"

devtools/sigparse.sh → test/signal-state.sh

@@ -1,20 +1,23 @@
 #!/usr/bin/env bash
 #
-# Parse signal format in /proc.
+# Test kernel state: which signals caught, ignored, etc.
 #
 # Copied from:
 # https://unix.stackexchange.com/questions/85364/how-can-i-check-what-signals-a-process-is-listening-to
 #
 # Usage:
-#   devtools/sigparse.sh <function name>
+#   test/signal-state.sh <function name>
 
 sigparse() {
+  # Parse signal format in /proc.
+  local hex_mask=$1
+
   local i=0
 
   # bits="$(printf "16i 2o %X p" "0x$1" | dc)" # variant for busybox
 
   # hex to binary.  Could also do this with Python.
-  bits="$(printf "ibase=16; obase=2; %X\n" "0x$1" | bc)"
+  bits="$(printf 'ibase=16; obase=2; %X\n' "0x$hex_mask" | bc)"
   while test -n "$bits"; do
     i=$((i + 1))
     case "$bits" in
@@ -33,7 +36,18 @@ report() {
   done
 }
 
+do-child() {
+  echo
+  echo 'BACKGROUND CHILD'
+  $sh -c 'script=$1; sleep 0.5 & { sleep 0.2; $script report $!; }' -- $0
+
+  # TODO: I think we need a foreground child too.  It can just be a C program that
+  # prints its own PID, and then waits for a byte on stdin before it exits?
+}
+
 compare-shells() {
+  local do_child=${1:-}
+
   local -a shells=(bash dash mksh zsh bin/osh)
 
   # Hm non-interactive shells have consistency.
@@ -46,6 +60,10 @@ compare-shells() {
     echo
 
     $sh -c 'script=$1; $script report $$' -- $0
+
+    if test -n "$do_child"; then
+      do-child $sh
+    fi
   done
 
   echo
@@ -68,6 +86,10 @@ compare-shells() {
     esac
 
     $sh $more_flags -i -c 'script=$1; $script report $$' -- $0
+
+    if test -n "$do_child"; then
+      do-child $sh
+    fi
   done
 }
 

test/stateful.sh

@@ -26,6 +26,11 @@ export PYTHONPATH=.
 
 readonly BASE_DIR=_tmp/stateful
 
+run() {
+  ### for PYTHONPATH
+  "$@"
+}
+
 signals-quick() {
   spec/stateful/signals.py \
     $OSH bash "$@"