[interactive] Set signal state for SIGTTIN, SIGTTOU, etc.

Apparently job control shells need this.  Still needs more testing.

Also test signal state against bin/osh.

core/pyos.py

@@ -271,18 +271,24 @@ def __call__(self, sig_num, unused_frame):
 def SignalState_AfterForkingChild():
   # type: () -> None
   """Not a member of SignalState since we didn't do dependency injection."""
-  # Respond to Ctrl-\ (core dump)
-  signal.signal(signal.SIGQUIT, signal.SIG_DFL)
-
   # Python sets SIGPIPE handler to SIG_IGN by default.  Child processes
   # shouldn't have this.
   # https://docs.python.org/2/library/signal.html
   # See Python/pythonrun.c.
   signal.signal(signal.SIGPIPE, signal.SIG_DFL)
 
+  # Respond to Ctrl-\ (core dump)
+  signal.signal(signal.SIGQUIT, signal.SIG_DFL)
+
   # Child processes should get Ctrl-Z.
   signal.signal(signal.SIGTSTP, signal.SIG_DFL)
 
+  # More signals from
+  # https://www.gnu.org/software/libc/manual/html_node/Launching-Jobs.html
+  signal.signal(signal.SIGTTOU, signal.SIG_DFL)
+  signal.signal(signal.SIGTTIN, signal.SIG_DFL)
+  signal.signal(signal.SIGCHLD, signal.SIG_DFL)
+
 
 class SignalState(object):
   """All changes to global signal state go through this object."""
@@ -306,6 +312,12 @@ def InitInteractiveShell(self, display):
     # This prevents Ctrl-Z from suspending OSH in interactive mode.
     signal.signal(signal.SIGTSTP, signal.SIG_IGN)
 
+    # More signals from
+    # https://www.gnu.org/software/libc/manual/html_node/Initializing-the-Shell.html
+    signal.signal(signal.SIGTTOU, signal.SIG_IGN)
+    signal.signal(signal.SIGTTIN, signal.SIG_IGN)
+    signal.signal(signal.SIGCHLD, signal.SIG_IGN)
+
     # Register a callback to receive terminal width changes.
     # NOTE: In line_input.c, we turned off rl_catch_sigwinch.
 

devtools/sigparse.sh

@@ -34,7 +34,7 @@ report() {
 }
 
 compare-shells() {
-  local -a shells=(bash dash mksh zsh osh)
+  local -a shells=(bash dash mksh zsh bin/osh)
 
   # Hm non-interactive shells have consistency.
   # SIGCHLD and SIGINT are caught in bash, dash, zsh, mksh.  mksh catches
@@ -62,7 +62,7 @@ compare-shells() {
 
     local more_flags=''
     case $sh in
-      (bash|osh)
+      (bash|bin/osh)
         more_flags='--rcfile /dev/null'
         ;;
     esac