1 files changed, 553 insertions, 0 deletions

diff --git a/bin/cash/trap.c b/bin/cash/trap.c
new file mode 100644
index 00000000..9809770d
--- /dev/null
+++ b/bin/cash/trap.c
@@ -0,0 +1,553 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * 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.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)trap.c	8.5 (Berkeley) 6/5/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: releng/12.0/bin/sh/trap.c 326025 2017-11-20 19:49:47Z pfg $");
+
+#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 "builtins.h"
+#include "myhistedit.h"
+
+
+/*
+ * 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 permanently */
+#define S_RESET 5		/* temporary - to reset a hard ignored sig */
+
+
+static char sigmode[NSIG];	/* current value of signal */
+volatile sig_atomic_t pendingsig;	/* indicates some signal received */
+volatile sig_atomic_t pendingsig_waitcmd;	/* indicates wait builtin should be interrupted */
+static int in_dotrap;			/* do we execute in a trap handler? */
+static char *volatile trap[NSIG];	/* trap handler commands */
+static volatile sig_atomic_t gotsig[NSIG];
+				/* indicates specified signal received */
+static int ignore_sigchld;	/* Used while handling SIGCHLD traps. */
+static int last_trapsig;
+
+static int exiting;		/* exitshell() has been called */
+static int exiting_exitstatus;	/* value passed to exitshell() */
+
+static int getsigaction(int, sig_t *);
+
+
+/*
+ * Map a string to a signal number.
+ *
+ * Note: the signal number may exceed NSIG.
+ */
+static int
+sigstring_to_signum(char *sig)
+{
+
+	if (is_number(sig)) {
+		int signo;
+
+		signo = atoi(sig);
+		return ((signo >= 0 && signo < NSIG) ? signo : (-1));
+	} else if (strcasecmp(sig, "EXIT") == 0) {
+		return (0);
+	} else {
+		int n;
+
+		if (strncasecmp(sig, "SIG", 3) == 0)
+			sig += 3;
+		for (n = 1; n < sys_nsig; n++)
+			if (sys_signame[n] &&
+			    strcasecmp(sys_signame[n], sig) == 0)
+				return (n);
+	}
+	return (-1);
+}
+
+
+/*
+ * Print a list of valid signal names.
+ */
+static void
+printsignals(void)
+{
+	int n, outlen;
+
+	outlen = 0;
+	for (n = 1; n < sys_nsig; n++) {
+		if (sys_signame[n]) {
+			out1fmt("%s", sys_signame[n]);
+			outlen += strlen(sys_signame[n]);
+		} else {
+			out1fmt("%d", n);
+			outlen += 3;	/* good enough */
+		}
+		++outlen;
+		if (outlen > 71 || n == sys_nsig - 1) {
+			out1str("\n");
+			outlen = 0;
+		} else {
+			out1c(' ');
+		}
+	}
+}
+
+
+/*
+ * The trap builtin.
+ */
+int
+trapcmd(int argc __unused, char **argv)
+{
+	char *action;
+	int signo;
+	int errors = 0;
+	int i;
+
+	while ((i = nextopt("l")) != '\0') {
+		switch (i) {
+		case 'l':
+			printsignals();
+			return (0);
+		}
+	}
+	argv = argptr;
+
+	if (*argv == NULL) {
+		for (signo = 0 ; signo < sys_nsig ; signo++) {
+			if (signo < NSIG && trap[signo] != NULL) {
+				out1str("trap -- ");
+				out1qstr(trap[signo]);
+				if (signo == 0) {
+					out1str(" EXIT\n");
+				} else if (sys_signame[signo]) {
+					out1fmt(" %s\n", sys_signame[signo]);
+				} else {
+					out1fmt(" %d\n", signo);
+				}
+			}
+		}
+		return 0;
+	}
+	action = NULL;
+	if (*argv && !is_number(*argv)) {
+		if (strcmp(*argv, "-") == 0)
+			argv++;
+		else {
+			action = *argv;
+			argv++;
+		}
+	}
+	for (; *argv; argv++) {
+		if ((signo = sigstring_to_signum(*argv)) == -1) {
+			warning("bad signal %s", *argv);
+			errors = 1;
+			continue;
+		}
+		INTOFF;
+		if (action)
+			action = savestr(action);
+		if (trap[signo])
+			ckfree(trap[signo]);
+		trap[signo] = action;
+		if (signo != 0)
+			setsignal(signo);
+		INTON;
+	}
+	return errors;
+}
+
+
+/*
+ * Clear traps on a fork.
+ */
+void
+clear_traps(void)
+{
+	char *volatile *tp;
+
+	for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
+		if (*tp && **tp) {	/* trap not NULL or SIG_IGN */
+			INTOFF;
+			ckfree(*tp);
+			*tp = NULL;
+			if (tp != &trap[0])
+				setsignal(tp - trap);
+			INTON;
+		}
+	}
+}
+
+
+/*
+ * Check if we have any traps enabled.
+ */
+int
+have_traps(void)
+{
+	char *volatile *tp;
+
+	for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
+		if (*tp && **tp)	/* trap not NULL or SIG_IGN */
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Set the signal handler for the specified signal.  The routine figures
+ * out what it should be set to.
+ */
+void
+setsignal(int signo)
+{
+	int action;
+	sig_t sigact = SIG_DFL;
+	struct sigaction sa;
+	char *t;
+
+	if ((t = trap[signo]) == NULL)
+		action = S_DFL;
+	else if (*t != '\0')
+		action = S_CATCH;
+	else
+		action = S_IGN;
+	if (action == S_DFL) {
+		switch (signo) {
+		case SIGINT:
+			action = S_CATCH;
+			break;
+		case SIGQUIT:
+#ifdef DEBUG
+			{
+			extern int debug;
+
+			if (debug)
+				break;
+			}
+#endif
+			action = S_CATCH;
+			break;
+		case SIGTERM:
+			if (rootshell && iflag)
+				action = S_IGN;
+			break;
+#if JOBS
+		case SIGTSTP:
+		case SIGTTOU:
+			if (rootshell && mflag)
+				action = S_IGN;
+			break;
+#endif
+		}
+	}
+
+	t = &sigmode[signo];
+	if (*t == 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;
+		}
+		if (sigact == SIG_IGN) {
+			if (mflag && (signo == SIGTSTP ||
+			     signo == SIGTTIN || signo == SIGTTOU)) {
+				*t = S_IGN;	/* don't hard ignore these */
+			} else
+				*t = S_HARD_IGN;
+		} else {
+			*t = S_RESET;	/* force to be set */
+		}
+	}
+	if (*t == S_HARD_IGN || *t == action)
+		return;
+	switch (action) {
+		case S_DFL:	sigact = SIG_DFL;	break;
+		case S_CATCH:  	sigact = onsig;		break;
+		case S_IGN:	sigact = SIG_IGN;	break;
+	}
+	*t = action;
+	sa.sa_handler = sigact;
+	sa.sa_flags = 0;
+	sigemptyset(&sa.sa_mask);
+	sigaction(signo, &sa, NULL);
+}
+
+
+/*
+ * 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)
+{
+
+	if (sigmode[signo] == 0)
+		setsignal(signo);
+	if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
+		signal(signo, SIG_IGN);
+		sigmode[signo] = S_IGN;
+	}
+}
+
+
+int
+issigchldtrapped(void)
+{
+
+	return (trap[SIGCHLD] != NULL && *trap[SIGCHLD] != '\0');
+}
+
+
+/*
+ * Signal handler.
+ */
+void
+onsig(int signo)
+{
+
+	if (signo == SIGINT && trap[SIGINT] == NULL) {
+		/*
+		 * The !in_dotrap here is safe.  The only way we can arrive
+		 * here with in_dotrap set is that a trap handler set SIGINT to
+		 * SIG_DFL and killed itself.
+		 */
+		if (suppressint && !in_dotrap)
+			SET_PENDING_INT;
+		else
+			onint();
+		return;
+	}
+
+	/* If we are currently in a wait builtin, prepare to break it */
+	if (signo == SIGINT || signo == SIGQUIT)
+		pendingsig_waitcmd = signo;
+
+	if (trap[signo] != NULL && trap[signo][0] != '\0' &&
+	    (signo != SIGCHLD || !ignore_sigchld)) {
+		gotsig[signo] = 1;
+		pendingsig = signo;
+		pendingsig_waitcmd = signo;
+	}
+}
+
+
+/*
+ * Called to execute a trap.  Perhaps we should avoid entering new trap
+ * handlers while we are executing a trap handler.
+ */
+void
+dotrap(void)
+{
+	struct stackmark smark;
+	int i;
+	int savestatus, prev_evalskip, prev_skipcount;
+
+	in_dotrap++;
+	for (;;) {
+		pendingsig = 0;
+		pendingsig_waitcmd = 0;
+		for (i = 1; i < NSIG; i++) {
+			if (gotsig[i]) {
+				gotsig[i] = 0;
+				if (trap[i]) {
+					/*
+					 * Ignore SIGCHLD to avoid infinite
+					 * recursion if the trap action does
+					 * a fork.
+					 */
+					if (i == SIGCHLD)
+						ignore_sigchld++;
+
+					/*
+					 * Backup current evalskip
+					 * state and reset it before
+					 * executing a trap, so that the
+					 * trap is not disturbed by an
+					 * ongoing break/continue/return
+					 * statement.
+					 */
+					prev_evalskip  = evalskip;
+					prev_skipcount = skipcount;
+					evalskip = 0;
+
+					last_trapsig = i;
+					savestatus = exitstatus;
+					setstackmark(&smark);
+					evalstring(stsavestr(trap[i]), 0);
+					popstackmark(&smark);
+
+					/*
+					 * If such a command was not
+					 * already in progress, allow a
+					 * break/continue/return in the
+					 * trap action to have an effect
+					 * outside of it.
+					 */
+					if (evalskip == 0 ||
+					    prev_evalskip != 0) {
+						evalskip  = prev_evalskip;
+						skipcount = prev_skipcount;
+						exitstatus = savestatus;
+					}
+
+					if (i == SIGCHLD)
+						ignore_sigchld--;
+				}
+				break;
+			}
+		}
+		if (i >= NSIG)
+			break;
+	}
+	in_dotrap--;
+}
+
+
+/*
+ * Controls whether the shell is interactive or not based on iflag.
+ */
+void
+setinteractive(void)
+{
+	setsignal(SIGINT);
+	setsignal(SIGQUIT);
+	setsignal(SIGTERM);
+}
+
+
+/*
+ * Called to exit the shell.
+ */
+void
+exitshell(int status)
+{
+	TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
+	exiting = 1;
+	exiting_exitstatus = status;
+	exitshell_savedstatus();
+}
+
+void
+exitshell_savedstatus(void)
+{
+	struct jmploc loc1, loc2;
+	char *p;
+	int sig = 0;
+	sigset_t sigs;
+
+	if (!exiting) {
+		if (in_dotrap && last_trapsig) {
+			sig = last_trapsig;
+			exiting_exitstatus = sig + 128;
+		} else
+			exiting_exitstatus = oexitstatus;
+	}
+	exitstatus = oexitstatus = exiting_exitstatus;
+	if (!setjmp(loc1.loc)) {
+		handler = &loc1;
+		if ((p = trap[0]) != NULL && *p != '\0') {
+			/*
+			 * Reset evalskip, or the trap on EXIT could be
+			 * interrupted if the last command was a "return".
+			 */
+			evalskip = 0;
+			trap[0] = NULL;
+			FORCEINTON;
+			evalstring(p, 0);
+		}
+	}
+	if (!setjmp(loc2.loc)) {
+		handler = &loc2;		/* probably unnecessary */
+		FORCEINTON;
+		flushall();
+#if JOBS
+		setjobctl(0);
+#endif
+	}
+	if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN &&
+	    sig != SIGTTOU) {
+		signal(sig, SIG_DFL);
+		sigemptyset(&sigs);
+		sigaddset(&sigs, sig);
+		sigprocmask(SIG_UNBLOCK, &sigs, NULL);
+		kill(getpid(), sig);
+		/* If the default action is to ignore, fall back to _exit(). */
+	}
+	_exit(exiting_exitstatus);
+}