auto import from //depot/cupcake/@135843
diff --git a/sh/trap.c b/sh/trap.c
new file mode 100644
index 0000000..b3b2db4
--- /dev/null
+++ b/sh/trap.c
@@ -0,0 +1,470 @@
+/* $NetBSD: trap.c,v 1.31 2005/01/11 19:38:57 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. 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 1.31 2005/01/11 19:38:57 christos Exp $");
+#endif
+#endif /* not lint */
+
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.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"
+#include "var.h"
+
+static const char *sys_signame[NSIG] = {
+ "Unused",
+ "HUP", "INT", "QUIT", "ILL",
+ "TRAP", "ABRT", "BUS", "FPE",
+ "KILL", "USR1", "SEGV", "USR2",
+ "PIPE", "ALRM", "TERM",
+ "Unknown",
+ "CHLD",
+ "CONT", "STOP", "TSTP", "TTIN",
+ "TTOU", "URG", "XCPU", "XFSZ",
+ "VTALRM", "PROF", "WINCH", "IO",
+ "PWR", "SYS"
+};
+
+/*
+ * 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 */
+
+
+char *trap[NSIG+1]; /* trap handler commands */
+MKINIT char sigmode[NSIG]; /* current value of signal */
+char gotsig[NSIG]; /* indicates specified signal received */
+int pendingsigs; /* indicates some signal received */
+
+static int getsigaction(int, sig_t *);
+
+/*
+ * return the signal number described by `p' (as a number or a name)
+ * or -1 if it isn't one
+ */
+
+static int
+signame_to_signum(const char *p)
+{
+ int i;
+
+ if (is_number(p))
+ return number(p);
+
+ if (strcasecmp(p, "exit") == 0 )
+ return 0;
+
+ if (strncasecmp(p, "sig", 3) == 0)
+ p += 3;
+
+ for (i = 0; i < NSIG; ++i)
+ if (strcasecmp (p, sys_signame[i]) == 0)
+ return i;
+ return -1;
+}
+
+/*
+ * Print a list of valid signal names
+ */
+static void
+printsignals(void)
+{
+ int n;
+
+ out1str("EXIT ");
+
+ for (n = 1; n < NSIG; n++) {
+ out1fmt("%s", sys_signame[n]);
+ if ((n == NSIG/2) || n == (NSIG - 1))
+ out1str("\n");
+ else
+ out1c(' ');
+ }
+}
+
+/*
+ * The trap builtin.
+ */
+
+int
+trapcmd(int argc, char **argv)
+{
+ char *action;
+ char **ap;
+ int signo;
+
+ if (argc <= 1) {
+ for (signo = 0 ; signo <= NSIG ; signo++)
+ if (trap[signo] != NULL) {
+ out1fmt("trap -- ");
+ print_quoted(trap[signo]);
+ out1fmt(" %s\n",
+ (signo) ? sys_signame[signo] : "EXIT");
+ }
+ return 0;
+ }
+ ap = argv + 1;
+
+ action = NULL;
+
+ if (strcmp(*ap, "--") == 0)
+ if (*++ap == NULL)
+ return 0;
+
+ if (signame_to_signum(*ap) == -1) {
+ if ((*ap)[0] == '-') {
+ if ((*ap)[1] == '\0')
+ ap++;
+ else if ((*ap)[1] == 'l' && (*ap)[2] == '\0') {
+ printsignals();
+ return 0;
+ }
+ else
+ error("bad option %s\n", *ap);
+ }
+ else
+ action = *ap++;
+ }
+
+ while (*ap) {
+ if (is_number(*ap))
+ signo = number(*ap);
+ else
+ signo = signame_to_signum(*ap);
+
+ if (signo < 0 || signo > NSIG)
+ error("%s: bad trap", *ap);
+
+ INTOFF;
+ if (action)
+ action = savestr(action);
+
+ if (trap[signo])
+ ckfree(trap[signo]);
+
+ trap[signo] = action;
+
+ if (signo != 0)
+ setsignal(signo, 0);
+ INTON;
+ ap++;
+ }
+ return 0;
+}
+
+
+
+/*
+ * Clear traps on a fork or vfork.
+ * Takes one arg vfork, to tell it to not be destructive of
+ * the parents variables.
+ */
+
+void
+clear_traps(int vforked)
+{
+ char **tp;
+
+ for (tp = trap ; tp <= &trap[NSIG] ; tp++) {
+ if (*tp && **tp) { /* trap not NULL or SIG_IGN */
+ INTOFF;
+ if (!vforked) {
+ ckfree(*tp);
+ *tp = NULL;
+ }
+ if (tp != &trap[0])
+ setsignal(tp - trap, vforked);
+ INTON;
+ }
+ }
+}
+
+
+
+/*
+ * Set the signal handler for the specified signal. The routine figures
+ * out what it should be set to.
+ */
+
+long
+setsignal(int signo, int vforked)
+{
+ int action;
+ sig_t sigact = SIG_DFL;
+ struct sigaction act, oact;
+ char *t, tsig;
+
+ if ((t = trap[signo]) == NULL)
+ action = S_DFL;
+ else if (*t != '\0')
+ action = S_CATCH;
+ else
+ action = S_IGN;
+ if (rootshell && !vforked && 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 (!getsigaction(signo, &sigact)) {
+ /*
+ * 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 0;
+ }
+ if (sigact == 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 0;
+ switch (action) {
+ case S_DFL: sigact = SIG_DFL; break;
+ case S_CATCH: sigact = onsig; break;
+ case S_IGN: sigact = SIG_IGN; break;
+ }
+ if (!vforked)
+ *t = action;
+ act.sa_handler = sigact;
+ sigemptyset(&act.sa_mask);
+ act.sa_flags = 0;
+#ifdef SA_INTERRUPT
+ act.sa_flags |= SA_INTERRUPT;
+#endif
+ if(sigaction(signo, &act, &oact) < 0)
+ return (long) SIG_ERR;
+ return (long) oact.sa_handler;
+}
+
+/*
+ * Return the current setting for sig w/o changing it.
+ */
+static int
+getsigaction(int signo, sig_t *sigact)
+{
+ struct sigaction sa;
+
+ if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
+ return 0;
+ *sigact = (sig_t) sa.sa_handler;
+ return 1;
+}
+
+/*
+ * Ignore a signal.
+ */
+
+void
+ignoresig(int signo, int vforked)
+{
+ if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN)
+ bsd_signal(signo, SIG_IGN);
+ if (!vforked)
+ sigmode[signo - 1] = S_HARD_IGN;
+}
+
+
+#ifdef mkinit
+INCLUDE <signal.h>
+INCLUDE "trap.h"
+
+SHELLPROC {
+ char *sm;
+
+ clear_traps(0);
+ for (sm = sigmode ; sm < sigmode + NSIG ; sm++) {
+ if (*sm == S_IGN)
+ *sm = S_HARD_IGN;
+ }
+}
+#endif
+
+
+
+/*
+ * Signal handler.
+ */
+
+void
+onsig(int signo)
+{
+ bsd_signal(signo, onsig);
+ if (signo == SIGINT && trap[SIGINT] == NULL) {
+ onint();
+ return;
+ }
+ gotsig[signo - 1] = 1;
+ pendingsigs++;
+}
+
+
+
+/*
+ * Called to execute a trap. Perhaps we should avoid entering new trap
+ * handlers while we are executing a trap handler.
+ */
+
+void
+dotrap(void)
+{
+ int i;
+ int savestatus;
+
+ for (;;) {
+ for (i = 1 ; ; i++) {
+ if (gotsig[i - 1])
+ break;
+ if (i >= NSIG)
+ goto done;
+ }
+ gotsig[i - 1] = 0;
+ savestatus=exitstatus;
+ evalstring(trap[i], 0);
+ exitstatus=savestatus;
+ }
+done:
+ pendingsigs = 0;
+}
+
+
+
+/*
+ * Controls whether the shell is interactive or not.
+ */
+
+
+void
+setinteractive(int on)
+{
+ static int is_interactive;
+
+ if (on == is_interactive)
+ return;
+ setsignal(SIGINT, 0);
+ setsignal(SIGQUIT, 0);
+ setsignal(SIGTERM, 0);
+ is_interactive = on;
+}
+
+
+
+/*
+ * Called to exit the shell.
+ */
+
+void
+exitshell(int status)
+{
+ struct jmploc loc1, loc2;
+ char *p;
+
+ TRACE(("pid %d, exitshell(%d)\n", getpid(), status));
+ if (setjmp(loc1.loc)) {
+ goto l1;
+ }
+ if (setjmp(loc2.loc)) {
+ goto l2;
+ }
+ handler = &loc1;
+ if ((p = trap[0]) != NULL && *p != '\0') {
+ trap[0] = NULL;
+ evalstring(p, 0);
+ }
+l1: handler = &loc2; /* probably unnecessary */
+ flushall();
+#if JOBS
+ setjobctl(0);
+#endif
+l2: _exit(status);
+ /* NOTREACHED */
+}