Initial import.

1 files changed, 395 insertions, 0 deletions

diff --git a/src/trap.c b/src/trap.c
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+/*	$NetBSD: trap.c,v 1.28 2002/11/24 22:35:43 christos Exp $	*/
+
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)trap.c	8.5 (Berkeley) 6/5/95";
+#else
+__RCSID("$NetBSD: trap.c,v 1.28 2002/11/24 22:35:43 christos Exp $");
+#endif
+#endif /* not lint */
+
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "shell.h"
+#include "main.h"
+#include "nodes.h"	/* for other headers */
+#include "eval.h"
+#include "jobs.h"
+#include "show.h"
+#include "options.h"
+#include "syntax.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "trap.h"
+#include "mystring.h"
+
+#ifdef HETIO
+#include "hetio.h"
+#endif
+
+/*
+ * Sigmode records the current value of the signal handlers for the various
+ * modes.  A value of zero means that the current handler is not known.
+ * S_HARD_IGN indicates that the signal was ignored on entry to the shell,
+ */
+
+#define S_DFL 1			/* default signal handling (SIG_DFL) */
+#define S_CATCH 2		/* signal is caught */
+#define S_IGN 3			/* signal is ignored (SIG_IGN) */
+#define S_HARD_IGN 4		/* signal is ignored permenantly */
+#define S_RESET 5		/* temporary - to reset a hard ignored sig */
+
+
+/* trap handler commands */
+char *trap[NSIG];
+/* current value of signal */
+static char sigmode[NSIG - 1];
+/* indicates specified signal received */
+char gotsig[NSIG - 1];
+/* last pending signal */
+volatile sig_atomic_t pendingsigs;
+/* do we generate EXSIG events */
+int exsig;
+
+extern char *signal_names[];
+
+#ifdef mkinit
+INCLUDE <signal.h>
+INIT {
+	signal(SIGCHLD, SIG_DFL);
+}
+#endif
+
+/*
+ * The trap builtin.
+ */
+
+int
+trapcmd(int argc, char **argv)
+{
+	char *action;
+	char **ap;
+	int signo;
+
+	nextopt(nullstr);
+	ap = argptr;
+	if (!*ap) {
+		for (signo = 0 ; signo < NSIG ; signo++) {
+			if (trap[signo] != NULL) {
+				out1fmt(
+					"trap -- %s %s\n",
+					single_quote(trap[signo]),
+					signal_names[signo]
+				);
+			}
+		}
+		return 0;
+	}
+	if (!ap[1])
+		action = NULL;
+	else
+		action = *ap++;
+	while (*ap) {
+		if ((signo = decode_signal(*ap, 0)) < 0)
+			error("%s: bad trap", *ap);
+		INTOFF;
+		if (action) {
+			if (action[0] == '-' && action[1] == '\0')
+				action = NULL;
+			else
+				action = savestr(action);
+		}
+		if (trap[signo])
+			ckfree(trap[signo]);
+		trap[signo] = action;
+		if (signo != 0)
+			setsignal(signo);
+		INTON;
+		ap++;
+	}
+	return 0;
+}
+
+
+
+/*
+ * Clear traps on a fork.
+ */
+
+void
+clear_traps(void)
+{
+	char **tp;
+
+	for (tp = trap ; tp < &trap[NSIG] ; tp++) {
+		if (*tp && **tp) {	/* trap not NULL or SIG_IGN */
+			INTOFF;
+			ckfree(*tp);
+			*tp = NULL;
+			if (tp != &trap[0])
+				setsignal(tp - trap);
+			INTON;
+		}
+	}
+}
+
+
+
+/*
+ * Set the signal handler for the specified signal.  The routine figures
+ * out what it should be set to.
+ */
+
+void
+setsignal(int signo)
+{
+	int action;
+	char *t, tsig;
+	struct sigaction act;
+
+	if ((t = trap[signo]) == NULL)
+		action = S_DFL;
+	else if (*t != '\0')
+		action = S_CATCH;
+	else
+		action = S_IGN;
+	if (rootshell && action == S_DFL) {
+		switch (signo) {
+		case SIGINT:
+			if (iflag || minusc || sflag == 0)
+				action = S_CATCH;
+			break;
+		case SIGQUIT:
+#ifdef DEBUG
+			if (debug)
+				break;
+#endif
+			/* FALLTHROUGH */
+		case SIGTERM:
+			if (iflag)
+				action = S_IGN;
+			break;
+#if JOBS
+		case SIGTSTP:
+		case SIGTTOU:
+			if (mflag)
+				action = S_IGN;
+			break;
+#endif
+		}
+	}
+
+	t = &sigmode[signo - 1];
+	tsig = *t;
+	if (tsig == 0) {
+		/*
+		 * current setting unknown
+		 */
+		if (sigaction(signo, 0, &act) == -1) {
+			/*
+			 * Pretend it worked; maybe we should give a warning
+			 * here, but other shells don't. We don't alter
+			 * sigmode, so that we retry every time.
+			 */
+			return;
+		}
+		if (act.sa_handler == SIG_IGN) {
+			if (mflag && (signo == SIGTSTP ||
+			     signo == SIGTTIN || signo == SIGTTOU)) {
+				tsig = S_IGN;	/* don't hard ignore these */
+			} else
+				tsig = S_HARD_IGN;
+		} else {
+			tsig = S_RESET;	/* force to be set */
+		}
+	}
+	if (tsig == S_HARD_IGN || tsig == action)
+		return;
+	switch (action) {
+	case S_CATCH:
+		act.sa_handler = onsig;
+		break;
+	case S_IGN:
+		act.sa_handler = SIG_IGN;
+		break;
+	default:
+		act.sa_handler = SIG_DFL;
+	}
+	*t = action;
+	act.sa_flags = 0;
+	sigfillset(&act.sa_mask);
+	sigaction(signo, &act, 0);
+}
+
+/*
+ * Ignore a signal.
+ */
+
+void
+ignoresig(int signo)
+{
+	if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) {
+		signal(signo, SIG_IGN);
+	}
+	sigmode[signo - 1] = S_HARD_IGN;
+}
+
+
+
+/*
+ * Signal handler.
+ */
+
+void
+onsig(int signo)
+{
+	gotsig[signo - 1] = 1;
+	pendingsigs = signo;
+
+	if (exsig || (signo == SIGINT && !trap[SIGINT])) {
+		if (!suppressint)
+			onint();
+		intpending = 1;
+	}
+}
+
+
+
+/*
+ * Called to execute a trap.  Perhaps we should avoid entering new trap
+ * handlers while we are executing a trap handler.
+ */
+
+void
+dotrap(void)
+{
+	char *p;
+	char *q;
+	int savestatus;
+
+	savestatus = exitstatus;
+	q = gotsig;
+	while (pendingsigs = 0, barrier(), (p = memchr(q, 1, NSIG - 1))) {
+		*p = 0;
+		p = trap[p - q + 1];
+		if (!p)
+			continue;
+		evalstring(p);
+		exitstatus = savestatus;
+	}
+}
+
+
+
+/*
+ * Controls whether the shell is interactive or not.
+ */
+
+
+void
+setinteractive(int on)
+{
+	static int is_interactive;
+
+	if (++on == is_interactive)
+		return;
+	is_interactive = on;
+	setsignal(SIGINT);
+	setsignal(SIGQUIT);
+	setsignal(SIGTERM);
+}
+
+
+
+/*
+ * Called to exit the shell.
+ */
+
+void
+exitshell(void)
+{
+	struct jmploc loc;
+	char *p;
+	int status;
+	int jmp;
+
+#ifdef HETIO
+	hetio_reset_term();
+#endif
+	jmp = setjmp(loc.loc);
+	status = exitstatus;
+	TRACE(("pid %d, exitshell(%d)\n", getpid(), status));
+	if (jmp)
+		goto out;
+	handler = &loc;
+	if ((p = trap[0]) != NULL && *p != '\0') {
+		trap[0] = NULL;
+		evalstring(p);
+	}
+	flushall();
+out:
+	_exit(status);
+	/* NOTREACHED */
+}
+
+int decode_signal(const char *string, int minsig)
+{
+	int signo;
+
+	if (is_number(string)) {
+		signo = atoi(string);
+		if (signo >= NSIG) {
+			return -1;
+		}
+		return signo;
+	}
+
+	for (signo = minsig; signo < NSIG; signo++) {
+		if (!strcasecmp(string, signal_names[signo])) {
+			return signo;
+		}
+	}
+
+	return -1;
+}