This file is trap.def, from which is created trap.c. It implements the builtin "trap" in Bash. Copyright (C) 1987-2006 Free Software Foundation, Inc. This file is part of GNU Bash, the Bourne Again SHell. Bash is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. Bash is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Bash; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. $PRODUCES trap.c $BUILTIN trap $FUNCTION trap_builtin $SHORT_DOC trap [-lp] [arg signal_spec ...] The command ARG is to be read and executed when the shell receives signal(s) SIGNAL_SPEC. If ARG is absent (and a single SIGNAL_SPEC is supplied) or `-', each specified signal is reset to its original value. If ARG is the null string each SIGNAL_SPEC is ignored by the shell and by the commands it invokes. If a SIGNAL_SPEC is EXIT (0) the command ARG is executed on exit from the shell. If a SIGNAL_SPEC is DEBUG, ARG is executed after every simple command. If the`-p' option is supplied then the trap commands associated with each SIGNAL_SPEC are displayed. If no arguments are supplied or if only `-p' is given, trap prints the list of commands associated with each signal. Each SIGNAL_SPEC is either a signal name in or a signal number. Signal names are case insensitive and the SIG prefix is optional. `trap -l' prints a list of signal names and their corresponding numbers. Note that a signal can be sent to the shell with "kill -signal $$". $END #include #if defined (HAVE_UNISTD_H) # ifdef _MINIX # include # endif # include #endif #include "../bashtypes.h" #include #include #include "../bashansi.h" #include "../shell.h" #include "../trap.h" #include "common.h" #include "bashgetopt.h" static void showtrap __P((int)); static int display_traps __P((WORD_LIST *)); /* The trap command: trap trap trap -l trap -p [sigspec ...] trap [--] Set things up so that ARG is executed when SIGNAL(s) N is recieved. If ARG is the empty string, then ignore the SIGNAL(s). If there is no ARG, then set the trap for SIGNAL(s) to its original value. Just plain "trap" means to print out the list of commands associated with each signal number. Single arg of "-l" means list the signal names. */ /* Possible operations to perform on the list of signals.*/ #define SET 0 /* Set this signal to first_arg. */ #define REVERT 1 /* Revert to this signals original value. */ #define IGNORE 2 /* Ignore this signal. */ extern int posixly_correct; int trap_builtin (list) WORD_LIST *list; { int list_signal_names, display, result, opt; list_signal_names = display = 0; result = EXECUTION_SUCCESS; reset_internal_getopt (); while ((opt = internal_getopt (list, "lp")) != -1) { switch (opt) { case 'l': list_signal_names++; break; case 'p': display++; break; default: builtin_usage (); return (EX_USAGE); } } list = loptend; opt = DSIG_NOCASE|DSIG_SIGPREFIX; /* flags for decode_signal */ if (list_signal_names) return (display_signal_list ((WORD_LIST *)NULL, 1)); else if (display || list == 0) return (display_traps (list)); else { char *first_arg; int operation, sig, first_signal; operation = SET; first_arg = list->word->word; first_signal = first_arg && *first_arg && all_digits (first_arg) && signal_object_p (first_arg, opt); /* Backwards compatibility. XXX - question about whether or not we should throw an error if an all-digit argument doesn't correspond to a valid signal number (e.g., if it's `50' on a system with only 32 signals). */ if (first_signal) operation = REVERT; /* When in posix mode, the historical behavior of looking for a missing first argument is disabled. To revert to the original signal handling disposition, use `-' as the first argument. */ else if (posixly_correct == 0 && first_arg && *first_arg && (*first_arg != '-' || first_arg[1]) && signal_object_p (first_arg, opt) && list->next == 0) operation = REVERT; else { list = list->next; if (list == 0) { builtin_usage (); return (EX_USAGE); } else if (*first_arg == '\0') operation = IGNORE; else if (first_arg[0] == '-' && !first_arg[1]) operation = REVERT; } while (list) { sig = decode_signal (list->word->word, opt); if (sig == NO_SIG) { sh_invalidsig (list->word->word); result = EXECUTION_FAILURE; } else { switch (operation) { case SET: set_signal (sig, first_arg); break; case REVERT: restore_default_signal (sig); /* Signals that the shell treats specially need special handling. */ switch (sig) { case SIGINT: if (interactive) set_signal_handler (SIGINT, sigint_sighandler); else set_signal_handler (SIGINT, termsig_sighandler); break; case SIGQUIT: /* Always ignore SIGQUIT. */ set_signal_handler (SIGQUIT, SIG_IGN); break; case SIGTERM: #if defined (JOB_CONTROL) case SIGTTIN: case SIGTTOU: case SIGTSTP: #endif /* JOB_CONTROL */ if (interactive) set_signal_handler (sig, SIG_IGN); break; } break; case IGNORE: ignore_signal (sig); break; } } list = list->next; } } return (result); } static void showtrap (i) int i; { char *t, *p, *sn; p = trap_list[i]; if (p == (char *)DEFAULT_SIG) return; t = (p == (char *)IGNORE_SIG) ? (char *)NULL : sh_single_quote (p); sn = signal_name (i); /* Make sure that signals whose names are unknown (for whatever reason) are printed as signal numbers. */ if (STREQN (sn, "SIGJUNK", 7) || STREQN (sn, "unknown", 7)) printf ("trap -- %s %d\n", t ? t : "''", i); else if (posixly_correct) { if (STREQN (sn, "SIG", 3)) printf ("trap -- %s %s\n", t ? t : "''", sn+3); else printf ("trap -- %s %s\n", t ? t : "''", sn); } else printf ("trap -- %s %s\n", t ? t : "''", sn); FREE (t); } static int display_traps (list) WORD_LIST *list; { int result, i; if (list == 0) { for (i = 0; i < BASH_NSIG; i++) showtrap (i); return (EXECUTION_SUCCESS); } for (result = EXECUTION_SUCCESS; list; list = list->next) { i = decode_signal (list->word->word, DSIG_NOCASE|DSIG_SIGPREFIX); if (i == NO_SIG) { sh_invalidsig (list->word->word); result = EXECUTION_FAILURE; } else showtrap (i); } return (result); }