| [c28a023] | 1 | /* $NetBSD: trap.c,v 1.24 2000/05/22 10:18:47 elric Exp $ */
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| 2 |
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| 3 | /*-
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| 4 | * Copyright (c) 1991, 1993
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| 5 | * The Regents of the University of California. All rights reserved.
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| 6 | *
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| 7 | * This code is derived from software contributed to Berkeley by
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| 8 | * Kenneth Almquist.
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| 9 | *
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| 10 | * Redistribution and use in source and binary forms, with or without
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| 11 | * modification, are permitted provided that the following conditions
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| 12 | * are met:
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| 13 | * 1. Redistributions of source code must retain the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer.
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| 15 | * 2. Redistributions in binary form must reproduce the above copyright
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| 16 | * notice, this list of conditions and the following disclaimer in the
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| 17 | * documentation and/or other materials provided with the distribution.
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| 18 | * 3. All advertising materials mentioning features or use of this software
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| 19 | * must display the following acknowledgement:
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| 20 | * This product includes software developed by the University of
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| 21 | * California, Berkeley and its contributors.
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| 22 | * 4. Neither the name of the University nor the names of its contributors
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| 23 | * may be used to endorse or promote products derived from this software
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| 24 | * without specific prior written permission.
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| 25 | *
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| 26 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 27 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 28 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 29 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 30 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 31 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 32 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 33 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 34 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 35 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 36 | * SUCH DAMAGE.
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| 37 | */
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| 38 |
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| 39 | #include <sys/cdefs.h>
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| 40 | #ifndef lint
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| 41 | #if 0
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| 42 | static char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95";
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| 43 | #else
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| 44 | __RCSID("$NetBSD: trap.c,v 1.24 2000/05/22 10:18:47 elric Exp $");
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| 45 | #endif
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| 46 | #endif /* not lint */
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| 47 |
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| 48 | #include <signal.h>
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| 49 | #include <unistd.h>
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| 50 | #include <stdlib.h>
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| 51 |
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| 52 | #include "shell.h"
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| 53 | #include "main.h"
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| 54 | #include "nodes.h" /* for other headers */
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| 55 | #include "eval.h"
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| 56 | #include "jobs.h"
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| 57 | #include "show.h"
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| 58 | #include "options.h"
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| 59 | #include "syntax.h"
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| 60 | #include "output.h"
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| 61 | #include "memalloc.h"
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| 62 | #include "error.h"
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| 63 | #include "trap.h"
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| 64 | #include "mystring.h"
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| 65 | #include "mail.h"
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| 66 |
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| 67 | #ifdef HETIO
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| 68 | #include "hetio.h"
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| 69 | #endif
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| 70 |
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| 71 | /*
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| 72 | * Sigmode records the current value of the signal handlers for the various
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| 73 | * modes. A value of zero means that the current handler is not known.
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| 74 | * S_HARD_IGN indicates that the signal was ignored on entry to the shell,
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| 75 | */
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| 76 |
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| 77 | #define S_DFL 1 /* default signal handling (SIG_DFL) */
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| 78 | #define S_CATCH 2 /* signal is caught */
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| 79 | #define S_IGN 3 /* signal is ignored (SIG_IGN) */
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| 80 | #define S_HARD_IGN 4 /* signal is ignored permenantly */
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| 81 | #define S_RESET 5 /* temporary - to reset a hard ignored sig */
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| 82 |
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| 83 |
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| 84 | extern char nullstr[1]; /* null string */
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| 85 |
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| 86 | char *trap[NSIG+1]; /* trap handler commands */
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| 87 | MKINIT char sigmode[NSIG]; /* current value of signal */
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| 88 | char gotsig[NSIG]; /* indicates specified signal received */
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| 89 | int pendingsigs; /* indicates some signal received */
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| 90 |
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| 91 | extern char *signal_names[];
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| 92 |
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| 93 | /*
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| 94 | * The trap builtin.
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| 95 | */
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| 96 |
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| 97 | int
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| 98 | trapcmd(argc, argv)
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| 99 | int argc;
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| 100 | char **argv;
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| 101 | {
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| 102 | char *action;
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| 103 | char **ap;
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| 104 | int signo;
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| 105 |
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| 106 | if (argc <= 1) {
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| 107 | for (signo = 0 ; signo <= NSIG ; signo++) {
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| 108 | if (trap[signo] != NULL)
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| 109 | out1fmt("%d: %s\n", signo, trap[signo]);
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| 110 | }
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| 111 | return 0;
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| 112 | }
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| 113 | ap = argv + 1;
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| 114 | if (argc == 2)
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| 115 | action = NULL;
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| 116 | else
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| 117 | action = *ap++;
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| 118 | while (*ap) {
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| 119 | if ((signo = decode_signal(*ap)) < 0)
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| 120 | error("%s: bad trap", *ap);
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| 121 | INTOFF;
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| 122 | if (action) {
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| 123 | if (action[0] == '-' && action[1] == '\0')
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| 124 | action = NULL;
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| 125 | else
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| 126 | action = savestr(action);
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| 127 | }
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| 128 | if (trap[signo])
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| 129 | ckfree(trap[signo]);
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| 130 | trap[signo] = action;
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| 131 | if (signo != 0)
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| 132 | setsignal(signo);
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| 133 | INTON;
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| 134 | ap++;
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| 135 | }
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| 136 | return 0;
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| 137 | }
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| 138 |
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| 139 |
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| 140 |
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| 141 | /*
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| 142 | * Clear traps on a fork.
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| 143 | */
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| 144 |
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| 145 | void
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| 146 | clear_traps() {
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| 147 | char **tp;
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| 148 |
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| 149 | for (tp = trap ; tp <= &trap[NSIG] ; tp++) {
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| 150 | if (*tp && **tp) { /* trap not NULL or SIG_IGN */
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| 151 | INTOFF;
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| 152 | ckfree(*tp);
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| 153 | *tp = NULL;
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| 154 | if (tp != &trap[0])
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| 155 | setsignal(tp - trap);
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| 156 | INTON;
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| 157 | }
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| 158 | }
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| 159 | }
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| 160 |
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| 161 |
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| 162 |
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| 163 | /*
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| 164 | * Set the signal handler for the specified signal. The routine figures
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| 165 | * out what it should be set to.
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| 166 | */
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| 167 |
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| 168 | void
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| 169 | setsignal(signo)
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| 170 | int signo;
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| 171 | {
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| 172 | int action;
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| 173 | char *t;
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| 174 | struct sigaction act;
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| 175 |
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| 176 | if ((t = trap[signo]) == NULL)
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| 177 | action = S_DFL;
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| 178 | else if (*t != '\0')
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| 179 | action = S_CATCH;
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| 180 | else
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| 181 | action = S_IGN;
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| 182 | if (rootshell && action == S_DFL) {
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| 183 | switch (signo) {
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| 184 | case SIGINT:
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| 185 | if (iflag || minusc || sflag == 0)
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| 186 | action = S_CATCH;
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| 187 | break;
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| 188 | case SIGQUIT:
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| 189 | #ifdef DEBUG
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| 190 | {
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| 191 | extern int debug;
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| 192 |
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| 193 | if (debug)
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| 194 | break;
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| 195 | }
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| 196 | #endif
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| 197 | /* FALLTHROUGH */
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| 198 | case SIGTERM:
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| 199 | if (iflag)
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| 200 | action = S_IGN;
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| 201 | break;
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| 202 | #if JOBS
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| 203 | case SIGTSTP:
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| 204 | case SIGTTOU:
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| 205 | if (mflag)
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| 206 | action = S_IGN;
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| 207 | break;
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| 208 | #endif
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| 209 | }
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| 210 | }
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| 211 |
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| 212 | t = &sigmode[signo - 1];
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| 213 | if (*t == 0) {
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| 214 | /*
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| 215 | * current setting unknown
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| 216 | */
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| 217 | if (sigaction(signo, 0, &act) == -1) {
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| 218 | /*
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| 219 | * Pretend it worked; maybe we should give a warning
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| 220 | * here, but other shells don't. We don't alter
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| 221 | * sigmode, so that we retry every time.
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| 222 | */
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| 223 | return;
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| 224 | }
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| 225 | if (act.sa_handler == SIG_IGN) {
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| 226 | if (mflag && (signo == SIGTSTP ||
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| 227 | signo == SIGTTIN || signo == SIGTTOU)) {
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| 228 | *t = S_IGN; /* don't hard ignore these */
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| 229 | } else
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| 230 | *t = S_HARD_IGN;
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| 231 | } else {
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| 232 | *t = S_RESET; /* force to be set */
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| 233 | }
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| 234 | }
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| 235 | if (*t == S_HARD_IGN || *t == action)
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| 236 | return;
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| 237 | switch (action) {
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| 238 | case S_CATCH:
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| 239 | act.sa_handler = onsig;
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| 240 | break;
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| 241 | case S_IGN:
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| 242 | act.sa_handler = SIG_IGN;
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| 243 | break;
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| 244 | default:
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| 245 | act.sa_handler = SIG_DFL;
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| 246 | }
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| 247 | *t = action;
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| 248 | act.sa_flags = 0;
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| 249 | sigemptyset(&act.sa_mask);
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| 250 | sigaction(signo, &act, 0);
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| 251 | }
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| 252 |
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| 253 | /*
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| 254 | * Ignore a signal.
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| 255 | */
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| 256 |
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| 257 | void
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| 258 | ignoresig(signo)
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| 259 | int signo;
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| 260 | {
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| 261 | if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) {
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| 262 | signal(signo, SIG_IGN);
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| 263 | }
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| 264 | sigmode[signo - 1] = S_HARD_IGN;
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| 265 | }
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| 266 |
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| 267 |
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| 268 | #ifdef mkinit
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| 269 | INCLUDE <signal.h>
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| 270 | INCLUDE "trap.h"
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| 271 |
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| 272 | SHELLPROC {
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| 273 | char *sm;
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| 274 |
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| 275 | clear_traps();
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| 276 | for (sm = sigmode ; sm < sigmode + NSIG ; sm++) {
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| 277 | if (*sm == S_IGN)
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| 278 | *sm = S_HARD_IGN;
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| 279 | }
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| 280 | }
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| 281 | #endif
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| 282 |
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| 283 |
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| 284 |
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| 285 | /*
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| 286 | * Signal handler.
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| 287 | */
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| 288 |
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| 289 | void
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| 290 | onsig(signo)
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| 291 | int signo;
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| 292 | {
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| 293 | signal(signo, onsig);
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| 294 | if (signo == SIGINT && trap[SIGINT] == NULL) {
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| 295 | onint();
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| 296 | return;
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| 297 | }
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| 298 | gotsig[signo - 1] = 1;
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| 299 | pendingsigs++;
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| 300 | }
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| 301 |
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| 302 |
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| 303 |
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| 304 | /*
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| 305 | * Called to execute a trap. Perhaps we should avoid entering new trap
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| 306 | * handlers while we are executing a trap handler.
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| 307 | */
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| 308 |
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| 309 | void
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| 310 | dotrap() {
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| 311 | int i;
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| 312 | int savestatus;
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| 313 |
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| 314 | for (;;) {
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| 315 | for (i = 1 ; ; i++) {
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| 316 | if (gotsig[i - 1])
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| 317 | break;
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| 318 | if (i >= NSIG)
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| 319 | goto done;
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| 320 | }
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| 321 | gotsig[i - 1] = 0;
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| 322 | savestatus=exitstatus;
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| 323 | evalstring(trap[i], 0);
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| 324 | exitstatus=savestatus;
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| 325 | }
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| 326 | done:
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| 327 | pendingsigs = 0;
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| 328 | }
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| 329 |
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| 330 |
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| 331 |
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| 332 | /*
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| 333 | * Controls whether the shell is interactive or not.
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| 334 | */
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| 335 |
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| 336 |
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| 337 | void
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| 338 | setinteractive(on)
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| 339 | int on;
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| 340 | {
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| 341 | static int is_interactive;
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| 342 |
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| 343 | if (on == is_interactive)
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| 344 | return;
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| 345 | setsignal(SIGINT);
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| 346 | setsignal(SIGQUIT);
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| 347 | setsignal(SIGTERM);
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| 348 | chkmail(1);
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| 349 | is_interactive = on;
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| 350 | }
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| 351 |
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| 352 |
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| 353 |
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| 354 | /*
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| 355 | * Called to exit the shell.
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| 356 | */
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| 357 |
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| 358 | void
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| 359 | exitshell(status)
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| 360 | int status;
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| 361 | {
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| 362 | struct jmploc loc1, loc2;
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| 363 | char *p;
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| 364 |
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| 365 | TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
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| 366 | #ifdef HETIO
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| 367 | hetio_reset_term();
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| 368 | #endif
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| 369 | if (setjmp(loc1.loc)) {
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| 370 | goto l1;
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| 371 | }
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| 372 | if (setjmp(loc2.loc)) {
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| 373 | goto l2;
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| 374 | }
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| 375 | handler = &loc1;
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| 376 | if ((p = trap[0]) != NULL && *p != '\0') {
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| 377 | trap[0] = NULL;
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| 378 | evalstring(p, 0);
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| 379 | }
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| 380 | l1: handler = &loc2; /* probably unnecessary */
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| 381 | flushall();
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| 382 | #if JOBS
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| 383 | setjobctl(0);
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| 384 | #endif
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| 385 | l2: _exit(status);
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| 386 | /* NOTREACHED */
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| 387 | }
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| 388 |
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| 389 | int decode_signal(const char *string)
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| 390 | {
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| 391 | int signo;
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| 392 |
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| 393 | if (is_number(string)) return atoi(string);
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| 394 |
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| 395 | for (signo=0; signo < NSIG; signo++)
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| 396 | if (strcasecmp(string, signal_names[signo]) == 0 ||
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| 397 | strcasecmp(string, &(signal_names[signo])[3]) == 0)
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| 398 | return signo;
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| 399 |
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| 400 | return -1;
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| 401 | }
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