builtins/suspend.def

   1 This file is suspend.def, from which is created suspend.c.
   2 It implements the builtin "suspend" in Bash.
   3
   4 Copyright (C) 1987, 1989, 1991 Free Software Foundation, Inc.
   5
   6 This file is part of GNU Bash, the Bourne Again SHell.
   7
   8 Bash is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 1, or (at your option) any later
  11 version.
  12
  13 Bash is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License along
  19 with Bash; see the file COPYING.  If not, write to the Free Software
  20 Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  21
  22 $PRODUCES suspend.c
  23
  24 $BUILTIN suspend
  25 $DEPENDS_ON JOB_CONTROL
  26 $FUNCTION suspend_builtin
  27 $SHORT_DOC suspend [-f]
  28 Suspend the execution of this shell until it receives a SIGCONT
  29 signal.  The `-f' if specified says not to complain about this
  30 being a login shell if it is; just suspend anyway.
  31 $END
  32
  33 #include <sys/types.h>
  34 #include <signal.h>
  35 #include "../shell.h"
  36 #include "../jobs.h"
  37
  38 #if defined (JOB_CONTROL)
  39 extern int job_control;
  40
  41 static SigHandler *old_cont, *old_tstp;
  42
  43 /* Continue handler. */
  44 sighandler
  45 suspend_continue (sig)
  46      int sig;
  47 {
  48   set_signal_handler (SIGCONT, old_cont);
  49   set_signal_handler (SIGTSTP, old_tstp);
  50 #if !defined (VOID_SIGHANDLER)
  51   return (0);
  52 #endif /* !VOID_SIGHANDLER */
  53 }
  54
  55 /* Suspending the shell.  If -f is the arg, then do the suspend
  56    no matter what.  Otherwise, complain if a login shell. */
  57 int
  58 suspend_builtin (list)
  59      WORD_LIST *list;
  60 {
  61   if (!job_control)
  62     {
  63       builtin_error ("Cannot suspend a shell without job control");
  64       return (EXECUTION_FAILURE);
  65     }
  66
  67   if (list)
  68     if (strcmp (list->word->word, "-f") == 0)
  69       goto do_suspend;
  70
  71   no_args (list);
  72
  73   if (login_shell)
  74     {
  75       builtin_error ("Can't suspend a login shell");
  76       return (EXECUTION_FAILURE);
  77     }
  78
  79 do_suspend:
  80   old_cont = (SigHandler *)set_signal_handler (SIGCONT, suspend_continue);
  81   old_tstp = (SigHandler *)set_signal_handler (SIGTSTP, SIG_DFL);
  82   killpg (shell_pgrp, SIGTSTP);
  83   return (EXECUTION_SUCCESS);
  84 }
  85
  86 #endif /* JOB_CONTROL */