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 2, 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, 59 Temple Place, Suite 330, Boston, MA 02111 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 a SIGNAL_SPEC is EXIT (0) the command ARG is executed on exit from
32 the shell. If a 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. Each 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)
46 # include <sys/types.h>
51 #include "../bashtypes.h"
54 #include "../bashansi.h"
59 #include "bashgetopt.h"
61 static void showtrap __P((int));
62 static int display_traps __P((WORD_LIST *));
66 trap <arg> <signal ...>
72 Set things up so that ARG is executed when SIGNAL(s) N is recieved.
73 If ARG is the empty string, then ignore the SIGNAL(s). If there is
74 no ARG, then set the trap for SIGNAL(s) to its original value. Just
75 plain "trap" means to print out the list of commands associated with
76 each signal number. Single arg of "-l" means list the signal names. */
78 /* Possible operations to perform on the list of signals.*/
79 #define SET 0 /* Set this signal to first_arg. */
80 #define REVERT 1 /* Revert to this signals original value. */
81 #define IGNORE 2 /* Ignore this signal. */
83 extern int posixly_correct;
89 int list_signal_names, display, result, opt;
91 list_signal_names = display = 0;
92 result = EXECUTION_SUCCESS;
93 reset_internal_getopt ();
94 while ((opt = internal_getopt (list, "lp")) != -1)
111 if (list_signal_names)
112 return (display_signal_list ((WORD_LIST *)NULL, 1));
113 else if (display || list == 0)
114 return (display_traps (list));
121 first_arg = list->word->word;
122 if (first_arg && *first_arg && (*first_arg != '-' || first_arg[1]) &&
123 signal_object_p (first_arg))
128 if (*first_arg == '\0')
130 else if (first_arg[0] == '-' && !first_arg[1])
136 sig = decode_signal (list->word->word);
140 builtin_error ("%s: not a signal specification",
142 result = EXECUTION_FAILURE;
149 set_signal (sig, first_arg);
153 restore_default_signal (sig);
155 /* Signals that the shell treats specially need special
161 set_signal_handler (SIGINT, sigint_sighandler);
163 set_signal_handler (SIGINT, termination_unwind_protect);
167 /* Always ignore SIGQUIT. */
168 set_signal_handler (SIGQUIT, SIG_IGN);
171 #if defined (JOB_CONTROL)
175 #endif /* JOB_CONTROL */
177 set_signal_handler (sig, SIG_IGN);
202 if (p == (char *)DEFAULT_SIG)
205 t = (p == (char *)IGNORE_SIG) ? (char *)NULL : sh_single_quote (p);
206 sn = signal_name (i);
207 /* Make sure that signals whose names are unknown (for whatever reason)
208 are printed as signal numbers. */
209 if (STREQN (sn, "SIGJUNK", 7) || STREQN (sn, "unknown", 7))
210 printf ("trap -- %s %d\n", t ? t : "''", i);
211 else if (posixly_correct)
213 if (STREQN (sn, "SIG", 3))
214 printf ("trap -- %s %s\n", t ? t : "''", sn+3);
216 printf ("trap -- %s %s\n", t ? t : "''", sn);
219 printf ("trap -- %s %s\n", t ? t : "''", sn);
232 for (i = 0; i < BASH_NSIG; i++)
234 return (EXECUTION_SUCCESS);
237 for (result = EXECUTION_SUCCESS; list; list = list->next)
239 i = decode_signal (list->word->word);
242 result = EXECUTION_FAILURE;
243 builtin_error ("%s: not a signal specification", list->word->word);