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 int display_traps ();
65 trap <arg> <signal ...>
71 Set things up so that ARG is executed when SIGNAL(s) N is recieved.
72 If ARG is the empty string, then ignore the SIGNAL(s). If there is
73 no ARG, then set the trap for SIGNAL(s) to its original value. Just
74 plain "trap" means to print out the list of commands associated with
75 each signal number. Single arg of "-l" means list the signal names. */
77 /* Possible operations to perform on the list of signals.*/
78 #define SET 0 /* Set this signal to first_arg. */
79 #define REVERT 1 /* Revert to this signals original value. */
80 #define IGNORE 2 /* Ignore this signal. */
82 extern int interactive, posixly_correct;
88 int list_signal_names, display, result, opt;
90 list_signal_names = display = 0;
91 result = EXECUTION_SUCCESS;
92 reset_internal_getopt ();
93 while ((opt = internal_getopt (list, "lp")) != -1)
110 if (list_signal_names)
111 return (display_signal_list ((WORD_LIST *)NULL, 1));
112 else if (display || list == 0)
113 return (display_traps (list));
120 first_arg = list->word->word;
121 if (first_arg && *first_arg && (*first_arg != '-' || first_arg[1]) &&
122 signal_object_p (first_arg))
127 if (*first_arg == '\0')
129 else if (first_arg[0] == '-' && !first_arg[1])
135 sig = decode_signal (list->word->word);
139 builtin_error ("%s: not a signal specification",
141 result = EXECUTION_FAILURE;
148 set_signal (sig, first_arg);
152 restore_default_signal (sig);
154 /* Signals that the shell treats specially need special
160 set_signal_handler (SIGINT, sigint_sighandler);
162 set_signal_handler (SIGINT, termination_unwind_protect);
166 /* Always ignore SIGQUIT. */
167 set_signal_handler (SIGQUIT, SIG_IGN);
170 #if defined (JOB_CONTROL)
174 #endif /* JOB_CONTROL */
176 set_signal_handler (sig, SIG_IGN);
201 if (p == (char *)DEFAULT_SIG)
204 t = (p == (char *)IGNORE_SIG) ? (char *)NULL : sh_single_quote (p);
205 sn = signal_name (i);
206 /* Make sure that signals whose names are unknown (for whatever reason)
207 are printed as signal numbers. */
208 if (STREQN (sn, "SIGJUNK", 7) || STREQN (sn, "unknown", 7))
209 printf ("trap -- %s %d\n", t ? t : "''", i);
210 else if (posixly_correct)
212 if (STREQN (sn, "SIG", 3))
213 printf ("trap -- %s %s\n", t ? t : "''", sn+3);
215 printf ("trap -- %s %s\n", t ? t : "''", sn);
218 printf ("trap -- %s %s\n", t ? t : "''", sn);
231 for (i = 0; i <= NSIG; i++)
233 return (EXECUTION_SUCCESS);
236 for (result = EXECUTION_SUCCESS; list; list = list->next)
238 i = decode_signal (list->word->word);
241 result = EXECUTION_FAILURE;
242 builtin_error ("%s: not a signal specification", list->word->word);