1 This file is trap.def, from which is created trap.c.
2 It implements the builtin "trap" in Bash.
4 Copyright (C) 1987, 1989, 1991 Free Software Foundation, Inc.
6 This file is part of GNU Bash, the Bourne Again SHell.
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
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
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.
25 $FUNCTION trap_builtin
26 $SHORT_DOC trap [arg] [signal_spec] or trap -l
27 The command ARG is to be read and executed when the shell receives
28 signal(s) SIGNAL_SPEC. If ARG is absent all specified signals are
29 reset to their original values. If ARG is the null string each
30 SIGNAL_SPEC is ignored by the shell and by the commands it invokes.
31 If SIGNAL_SPEC is EXIT (0) the command ARG is executed on exit from
32 the shell. If SIGNAL_SPEC is DEBUG, ARG is executed after every
33 command. If ARG is `-p' then the trap commands associated with
34 each SIGNAL_SPEC are displayed. If no arguments are supplied or if
35 only `-p' is given, trap prints the list of commands associated with
36 each signal number. SIGNAL_SPEC is either a signal name in <signal.h>
37 or a signal number. `trap -l' prints a list of signal names and their
38 corresponding numbers. Note that a signal can be sent to the shell
39 with "kill -signal $$".
44 #if defined (HAVE_UNISTD_H)
48 #include "../bashtypes.h"
51 #include "../bashansi.h"
56 #include "bashgetopt.h"
58 static int display_traps ();
62 trap <arg> <signal ...>
68 Set things up so that ARG is executed when SIGNAL(s) N is recieved.
69 If ARG is the empty string, then ignore the SIGNAL(s). If there is
70 no ARG, then set the trap for SIGNAL(s) to its original value. Just
71 plain "trap" means to print out the list of commands associated with
72 each signal number. Single arg of "-l" means list the signal names. */
74 /* Possible operations to perform on the list of signals.*/
75 #define SET 0 /* Set this signal to first_arg. */
76 #define REVERT 1 /* Revert to this signals original value. */
77 #define IGNORE 2 /* Ignore this signal. */
79 extern int interactive;
85 int list_signal_names, display, result, opt;
87 list_signal_names = display = 0;
88 result = EXECUTION_SUCCESS;
89 reset_internal_getopt ();
90 while ((opt = internal_getopt (list, "lp")) != -1)
107 if (list_signal_names)
108 return (display_signal_list ((WORD_LIST *)NULL, 1));
109 else if (display || list == 0)
110 return (display_traps (list));
117 first_arg = list->word->word;
118 if (first_arg && *first_arg && signal_object_p (first_arg))
123 if (*first_arg == '\0')
125 else if (first_arg[0] == '-' && !first_arg[1])
131 sig = decode_signal (list->word->word);
135 builtin_error ("%s: not a signal specification",
137 result = EXECUTION_FAILURE;
144 set_signal (sig, first_arg);
148 restore_default_signal (sig);
150 /* Signals that the shell treats specially need special
156 set_signal_handler (SIGINT, sigint_sighandler);
158 set_signal_handler (SIGINT, termination_unwind_protect);
162 /* Always ignore SIGQUIT. */
163 set_signal_handler (SIGQUIT, SIG_IGN);
166 #if defined (JOB_CONTROL)
170 #endif /* JOB_CONTROL */
172 set_signal_handler (sig, SIG_IGN);
197 if (p == (char *)DEFAULT_SIG)
200 t = (p == (char *)IGNORE_SIG) ? (char *)NULL : single_quote (p);
201 printf ("trap -- %s %s\n", t ? t : "''", signal_name (i));
214 for (i = 0; i <= NSIG; i++)
216 return (EXECUTION_SUCCESS);
219 for (result = EXECUTION_SUCCESS; list; list = list->next)
221 i = decode_signal (list->word->word);
224 result = EXECUTION_FAILURE;
225 builtin_error ("%s: not a signal specification", list->word->word);