X-Git-Url: http://review.tizen.org/git/?p=platform%2Fupstream%2Fbash.git;a=blobdiff_plain;f=trap.c;h=edce31ab9ba90926abe03f88920d5f20ac526a88;hp=a24130f4b9cc984d5861df657035aff2ca4a6046;hb=HEAD;hpb=28ef6c316f1aff914bb95ac09787a3c83c1815fd

diff --git a/trap.c b/trap.c
index a24130f..edce31a 100644
--- a/trap.c
+++ b/trap.c
@@ -1,23 +1,23 @@
 /* trap.c -- Not the trap command, but useful functions for manipulating
    those objects.  The trap command is in builtins/trap.def. */
 
-/* Copyright (C) 1987, 1991 Free Software Foundation, Inc.
+/* Copyright (C) 1987-2013 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 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 3 of the License, 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.
+   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. */
+   You should have received a copy of the GNU General Public License
+   along with Bash.  If not, see <http://www.gnu.org/licenses/>.
+*/
 
 #include "config.h"
 
@@ -31,12 +31,25 @@
 #include <stdio.h>
 #include <errno.h>
 
+#include "bashintl.h"
+
+#include <signal.h>
+
 #include "trap.h"
 
 #include "shell.h"
+#include "flags.h"
 #include "input.h"	/* for save_token_state, restore_token_state */
+#include "jobs.h"
 #include "signames.h"
+#include "builtins.h"
 #include "builtins/common.h"
+#include "builtins/builtext.h"
+
+#if defined (READLINE)
+#  include <readline/readline.h>
+#  include "bashline.h"
+#endif
 
 #ifndef errno
 extern int errno;
@@ -52,28 +65,46 @@ extern int errno;
 #define SIG_CHANGED	0x20	/* Trap value changed in trap handler. */
 #define SIG_IGNORED	0x40	/* The signal is currently being ignored. */
 
+#define SPECIAL_TRAP(s)	((s) == EXIT_TRAP || (s) == DEBUG_TRAP || (s) == ERROR_TRAP || (s) == RETURN_TRAP)
+
 /* An array of such flags, one for each signal, describing what the
    shell will do with a signal.  DEBUG_TRAP == NSIG; some code below
    assumes this. */
-static int sigmodes[NSIG+1];
+static int sigmodes[BASH_NSIG];
+
+static void free_trap_command __P((int));
+static void change_signal __P((int, char *));
 
-static void change_signal (), restore_signal ();
+static int _run_trap_internal __P((int, char *));
+
+static void free_trap_string __P((int));
+static void reset_signal __P((int));
+static void restore_signal __P((int));
+static void reset_or_restore_signal_handlers __P((sh_resetsig_func_t *));
 
 /* Variables used here but defined in other files. */
-extern int interactive_shell, interactive;
-extern int interrupt_immediately;
 extern int last_command_exit_value;
 extern int line_number;
 
+extern int sigalrm_seen;
+extern procenv_t alrmbuf;
+
+extern char *this_command_name;
+extern sh_builtin_func_t *this_shell_builtin;
+extern procenv_t wait_intr_buf;
+extern int return_catch_flag, return_catch_value;
+extern int subshell_level;
+extern WORD_LIST *subst_assign_varlist;
+
 /* The list of things to do originally, before we started trapping. */
 SigHandler *original_signals[NSIG];
 
 /* For each signal, a slot for a string, which is a command to be
-   executed when that signal is recieved.  The slot can also contain
+   executed when that signal is received.  The slot can also contain
    DEFAULT_SIG, which means do whatever you were going to do before
    you were so rudely interrupted, or IGNORE_SIG, which says ignore
    this signal. */
-char *trap_list[NSIG+1];
+char *trap_list[BASH_NSIG];
 
 /* A bitmap of signals received for which we have trap handlers. */
 int pending_traps[NSIG];
@@ -84,64 +115,78 @@ int pending_traps[NSIG];
    trap command (e.g., when `return' is executed in the trap command). */
 int running_trap;
 
-/* The value of line_number when the trap started executing, since
-   parse_and_execute resets it to 1 and the trap command might want
-   it. */
-int trap_line_number;
+/* Set to last_command_exit_value before running a trap. */
+int trap_saved_exit_value;
+
+/* The (trapped) signal received while executing in the `wait' builtin */
+int wait_signal_received;
+
+int trapped_signal_received;
+
+#define GETORIGSIG(sig) \
+  do { \
+    original_signals[sig] = (SigHandler *)set_signal_handler (sig, SIG_DFL); \
+    set_signal_handler (sig, original_signals[sig]); \
+    if (original_signals[sig] == SIG_IGN) \
+      sigmodes[sig] |= SIG_HARD_IGNORE; \
+  } while (0)
 
-/* A value which can never be the target of a trap handler. */
-#define IMPOSSIBLE_TRAP_HANDLER (SigHandler *)initialize_traps
+#define SETORIGSIG(sig,handler) \
+  do { \
+    original_signals[sig] = handler; \
+    if (original_signals[sig] == SIG_IGN) \
+      sigmodes[sig] |= SIG_HARD_IGNORE; \
+  } while (0)
+
+#define GET_ORIGINAL_SIGNAL(sig) \
+  if (sig && sig < NSIG && original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) \
+    GETORIGSIG(sig)
 
 void
 initialize_traps ()
 {
   register int i;
 
-  trap_list[EXIT_TRAP] = trap_list[DEBUG_TRAP] = (char *)NULL;
-  sigmodes[EXIT_TRAP] = sigmodes[DEBUG_TRAP] = SIG_INHERITED;
+  initialize_signames();
+
+  trap_list[EXIT_TRAP] = trap_list[DEBUG_TRAP] = trap_list[ERROR_TRAP] = trap_list[RETURN_TRAP] = (char *)NULL;
+  sigmodes[EXIT_TRAP] = sigmodes[DEBUG_TRAP] = sigmodes[ERROR_TRAP] = sigmodes[RETURN_TRAP] = SIG_INHERITED;
   original_signals[EXIT_TRAP] = IMPOSSIBLE_TRAP_HANDLER;
 
   for (i = 1; i < NSIG; i++)
     {
       pending_traps[i] = 0;
       trap_list[i] = (char *)DEFAULT_SIG;
-      sigmodes[i] = SIG_INHERITED;
+      sigmodes[i] = SIG_INHERITED;	/* XXX - only set, not used */
       original_signals[i] = IMPOSSIBLE_TRAP_HANDLER;
     }
 
   /* Show which signals are treated specially by the shell. */
 #if defined (SIGCHLD)
-  original_signals[SIGCHLD] =
-    (SigHandler *) set_signal_handler (SIGCHLD, SIG_DFL);
-  set_signal_handler (SIGCHLD, original_signals[SIGCHLD]);
+  GETORIGSIG (SIGCHLD);
   sigmodes[SIGCHLD] |= (SIG_SPECIAL | SIG_NO_TRAP);
 #endif /* SIGCHLD */
 
-  original_signals[SIGINT] =
-    (SigHandler *) set_signal_handler (SIGINT, SIG_DFL);
-  set_signal_handler (SIGINT, original_signals[SIGINT]);
+  GETORIGSIG (SIGINT);
   sigmodes[SIGINT] |= SIG_SPECIAL;
 
 #if defined (__BEOS__)
   /* BeOS sets SIGINT to SIG_IGN! */
   original_signals[SIGINT] = SIG_DFL;
+  sigmodes[SIGINT] &= ~SIG_HARD_IGNORE;
 #endif
 
-  original_signals[SIGQUIT] =
-    (SigHandler *) set_signal_handler (SIGQUIT, SIG_DFL);
-  set_signal_handler (SIGQUIT, original_signals[SIGQUIT]);
+  GETORIGSIG (SIGQUIT);
   sigmodes[SIGQUIT] |= SIG_SPECIAL;
 
   if (interactive)
     {
-      original_signals[SIGTERM] =
-	(SigHandler *)set_signal_handler (SIGTERM, SIG_DFL);
-      set_signal_handler (SIGTERM, original_signals[SIGTERM]);
+      GETORIGSIG (SIGTERM);
       sigmodes[SIGTERM] |= SIG_SPECIAL;
     }
 }
 
-#ifdef INCLUDE_UNUSED
+#ifdef DEBUG
 /* Return a printable representation of the trap handler for SIG. */
 static char *
 trap_handler_string (sig)
@@ -168,9 +213,10 @@ signal_name (sig)
   char *ret;
 
   /* on cygwin32, signal_names[sig] could be null */
-  ret = (sig > NSIG || sig < 0) ? "bad signal number" : signal_names[sig];
-  if (ret == NULL)
-    ret = "unrecognized signal number";
+  ret = (sig >= BASH_NSIG || sig < 0 || signal_names[sig] == NULL)
+	? _("invalid signal number")
+	: signal_names[sig];
+
   return ret;
 }
 
@@ -179,22 +225,45 @@ signal_name (sig)
    then (int)2 is returned.  Return NO_SIG if STRING doesn't
    contain a valid signal descriptor. */
 int
-decode_signal (string)
+decode_signal (string, flags)
      char *string;
+     int flags;
 {
-  long sig;
+  intmax_t sig;
+  char *name;
 
   if (legal_number (string, &sig))
-    return ((sig >= 0 && sig <= NSIG) ? (int)sig : NO_SIG);
+    return ((sig >= 0 && sig < NSIG) ? (int)sig : NO_SIG);
 
   /* A leading `SIG' may be omitted. */
-  for (sig = 0; sig <= NSIG; sig++)
+  for (sig = 0; sig < BASH_NSIG; sig++)
     {
-      if (signal_names[sig] == 0 || signal_names[sig][0] == '\0')
+      name = signal_names[sig];
+      if (name == 0 || name[0] == '\0')
 	continue;
-      if (strcasecmp (string, signal_names[sig]) == 0 ||
-	  (STREQN (signal_names[sig], "SIG", 3) &&
-	    strcasecmp (string, &(signal_names[sig])[3]) == 0))
+
+      /* Check name without the SIG prefix first case sensitively or
+	 insensitively depending on whether flags includes DSIG_NOCASE */
+      if (STREQN (name, "SIG", 3))
+	{
+	  name += 3;
+
+	  if ((flags & DSIG_NOCASE) && strcasecmp (string, name) == 0)
+	    return ((int)sig);
+	  else if ((flags & DSIG_NOCASE) == 0 && strcmp (string, name) == 0)
+	    return ((int)sig);
+	  /* If we can't use the `SIG' prefix to match, punt on this
+	     name now. */
+	  else if ((flags & DSIG_SIGPREFIX) == 0)
+	    continue;
+	}
+
+      /* Check name with SIG prefix case sensitively or insensitively
+	 depending on whether flags includes DSIG_NOCASE */
+      name = signal_names[sig];
+      if ((flags & DSIG_NOCASE) && strcasecmp (string, name) == 0)
+	return ((int)sig);
+      else if ((flags & DSIG_NOCASE) == 0 && strcmp (string, name) == 0)
 	return ((int)sig);
     }
 
@@ -208,15 +277,35 @@ void
 run_pending_traps ()
 {
   register int sig;
-  int old_exit_value, *token_state;
+  int old_exit_value;
+  WORD_LIST *save_subst_varlist;
+  sh_parser_state_t pstate;
+#if defined (ARRAY_VARS)
+  ARRAY *ps;
+#endif
 
   if (catch_flag == 0)		/* simple optimization */
     return;
 
-  catch_flag = 0;
+  if (running_trap > 0)
+    {
+#if defined (DEBUG)
+      internal_warning ("run_pending_traps: recursive invocation while running trap for signal %d", running_trap-1);
+#endif
+#if 0
+      return;			/* no recursive trap invocations */
+#else
+      ;
+#endif
+    }
+
+  catch_flag = trapped_signal_received = 0;
 
   /* Preserve $? when running trap. */
   old_exit_value = last_command_exit_value;
+#if defined (ARRAY_VARS)
+  ps = save_pipestatus_array ();
+#endif
 
   for (sig = 1; sig < NSIG; sig++)
     {
@@ -224,25 +313,44 @@ run_pending_traps ()
 	 while (pending_traps[sig]--) instead of the if statement. */
       if (pending_traps[sig])
 	{
-#if defined (HAVE_POSIX_SIGNALS)
-	  sigset_t set, oset;
-
-	  sigemptyset (&set);
-	  sigemptyset (&oset);
+	  if (running_trap == sig+1)
+	    /*continue*/;
 
-	  sigaddset (&set, sig);
-	  sigprocmask (SIG_BLOCK, &set, &oset);
-#else
-#  if defined (HAVE_BSD_SIGNALS)
-	  int oldmask = sigblock (sigmask (sig));
-#  endif
-#endif /* HAVE_POSIX_SIGNALS */
+	  running_trap = sig + 1;
 
 	  if (sig == SIGINT)
 	    {
+	      pending_traps[sig] = 0;	/* XXX */
 	      run_interrupt_trap ();
 	      CLRINTERRUPT;
 	    }
+#if defined (JOB_CONTROL) && defined (SIGCHLD)
+	  else if (sig == SIGCHLD &&
+		   trap_list[SIGCHLD] != (char *)IMPOSSIBLE_TRAP_HANDLER &&
+		   (sigmodes[SIGCHLD] & SIG_INPROGRESS) == 0)
+	    {
+	      sigmodes[SIGCHLD] |= SIG_INPROGRESS;
+	      run_sigchld_trap (pending_traps[sig]);	/* use as counter */
+	      sigmodes[SIGCHLD] &= ~SIG_INPROGRESS;
+	    }
+	  else if (sig == SIGCHLD &&
+		   trap_list[SIGCHLD] == (char *)IMPOSSIBLE_TRAP_HANDLER &&
+		   (sigmodes[SIGCHLD] & SIG_INPROGRESS) != 0)
+	    {
+	      /* This can happen when run_pending_traps is called while
+		 running a SIGCHLD trap handler. */
+	      running_trap = 0;
+	      /* want to leave pending_traps[SIGCHLD] alone here */
+	      continue;					/* XXX */
+	    }
+	  else if (sig == SIGCHLD && (sigmodes[SIGCHLD] & SIG_INPROGRESS))
+	    {
+	      /* whoops -- print warning? */
+	      running_trap = 0;		/* XXX */
+	      /* want to leave pending_traps[SIGCHLD] alone here */
+	      continue;
+	    }
+#endif
 	  else if (trap_list[sig] == (char *)DEFAULT_SIG ||
 		   trap_list[sig] == (char *)IGNORE_SIG ||
 		   trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER)
@@ -260,34 +368,43 @@ run_pending_traps ()
 		 Unless we catch this, the subshell will dump core when
 		 trap_list[SIGTERM] == DEFAULT_SIG, because DEFAULT_SIG is
 		 usually 0x0. */
-	      internal_warning ("run_pending_traps: bad value in trap_list[%d]: 0x%x",
-				sig, (int)trap_list[sig]);
+	      internal_warning (_("run_pending_traps: bad value in trap_list[%d]: %p"),
+				sig, trap_list[sig]);
 	      if (trap_list[sig] == (char *)DEFAULT_SIG)
 		{
-		  internal_warning ("run_pending_traps: signal handler is SIG_DFL, resending %d (%s) to myself", sig, signal_name (sig));
+		  internal_warning (_("run_pending_traps: signal handler is SIG_DFL, resending %d (%s) to myself"), sig, signal_name (sig));
 		  kill (getpid (), sig);
 		}
 	    }
 	  else
 	    {
-	      token_state = save_token_state ();
-	      parse_and_execute (savestring (trap_list[sig]), "trap", SEVAL_NONINT|SEVAL_NOHIST);
-	      restore_token_state (token_state);
-	      free (token_state);
-	    }
+	      /* XXX - should we use save_parser_state/restore_parser_state? */
+	      save_parser_state (&pstate);
+	      save_subst_varlist = subst_assign_varlist;
+	      subst_assign_varlist = 0;
 
-	  pending_traps[sig] = 0;
+#if defined (JOB_CONTROL)
+	      save_pipeline (1);	/* XXX only provides one save level */
+#endif
+	      /* XXX - set pending_traps[sig] = 0 here? */
+	      pending_traps[sig] = 0;
+	      evalstring (savestring (trap_list[sig]), "trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE);
+#if defined (JOB_CONTROL)
+	      restore_pipeline (1);
+#endif
 
-#if defined (HAVE_POSIX_SIGNALS)
-	  sigprocmask (SIG_SETMASK, &oset, (sigset_t *)NULL);
-#else
-#  if defined (HAVE_BSD_SIGNALS)
-	  sigsetmask (oldmask);
-#  endif
-#endif /* POSIX_VERSION */
+	      subst_assign_varlist = save_subst_varlist;
+	      restore_parser_state (&pstate);
+	    }
+
+	  pending_traps[sig] = 0;	/* XXX - move before evalstring? */
+	  running_trap = 0;
 	}
     }
 
+#if defined (ARRAY_VARS)
+  restore_pipestatus_array (ps);
+#endif
   last_command_exit_value = old_exit_value;
 }
 
@@ -297,20 +414,48 @@ trap_handler (sig)
 {
   int oerrno;
 
+  if ((sigmodes[sig] & SIG_TRAPPED) == 0)
+    {
+#if defined (DEBUG)
+      internal_warning ("trap_handler: signal %d: signal not trapped", sig);
+#endif
+      SIGRETURN (0);
+    }
+
   if ((sig >= NSIG) ||
       (trap_list[sig] == (char *)DEFAULT_SIG) ||
       (trap_list[sig] == (char *)IGNORE_SIG))
-    programming_error ("trap_handler: bad signal %d", sig);
+    programming_error (_("trap_handler: bad signal %d"), sig);
   else
     {
       oerrno = errno;
 #if defined (MUST_REINSTALL_SIGHANDLERS)
+#  if defined (JOB_CONTROL) && defined (SIGCHLD)
+      if (sig != SIGCHLD)
+#  endif /* JOB_CONTROL && SIGCHLD */
       set_signal_handler (sig, trap_handler);
 #endif /* MUST_REINSTALL_SIGHANDLERS */
 
       catch_flag = 1;
       pending_traps[sig]++;
 
+      trapped_signal_received = sig;
+
+      if (this_shell_builtin && (this_shell_builtin == wait_builtin))
+	{
+	  wait_signal_received = sig;
+	  if (interrupt_immediately)
+	    longjmp (wait_intr_buf, 1);
+	}
+
+#if defined (READLINE)
+      /* Set the event hook so readline will call it after the signal handlers
+	 finish executing, so if this interrupted character input we can get
+	 quick response. */
+      if (RL_ISSTATE (RL_STATE_SIGHANDLER) && interrupt_immediately == 0)
+        bashline_set_event_hook ();
+#endif
+
       if (interrupt_immediately)
 	run_pending_traps ();
 
@@ -320,6 +465,44 @@ trap_handler (sig)
   SIGRETURN (0);
 }
 
+int
+first_pending_trap ()
+{
+  register int i;
+
+  for (i = 1; i < NSIG; i++)
+    if (pending_traps[i])
+      return i;
+  return -1;
+}
+
+int
+any_signals_trapped ()
+{
+  register int i;
+
+  for (i = 1; i < NSIG; i++)
+    if (sigmodes[i] & SIG_TRAPPED)
+      return i;
+  return -1;
+}
+
+void
+check_signals ()
+{
+  CHECK_ALRM;		/* set by the read builtin */
+  QUIT;
+}
+
+/* Convenience functions the rest of the shell can use */
+void
+check_signals_and_traps ()
+{
+  check_signals ();
+
+  run_pending_traps ();
+}
+
 #if defined (JOB_CONTROL) && defined (SIGCHLD)
 
 #ifdef INCLUDE_UNUSED
@@ -332,15 +515,44 @@ set_sigchld_trap (command_string)
 }
 #endif
 
-/* Make COMMAND_STRING be executed when SIGCHLD is caught iff the current
-   SIGCHLD trap handler is DEFAULT_SIG. */
+/* Make COMMAND_STRING be executed when SIGCHLD is caught iff SIGCHLD
+   is not already trapped.  IMPOSSIBLE_TRAP_HANDLER is used as a sentinel
+   to make sure that a SIGCHLD trap handler run via run_sigchld_trap can
+   reset the disposition to the default and not have the original signal
+   accidentally restored, undoing the user's command. */
 void
 maybe_set_sigchld_trap (command_string)
      char *command_string;
 {
-  if ((sigmodes[SIGCHLD] & SIG_TRAPPED) == 0)
+  if ((sigmodes[SIGCHLD] & SIG_TRAPPED) == 0 && trap_list[SIGCHLD] == (char *)IMPOSSIBLE_TRAP_HANDLER)
     set_signal (SIGCHLD, command_string);
 }
+
+/* Temporarily set the SIGCHLD trap string to IMPOSSIBLE_TRAP_HANDLER.  Used
+   as a sentinel in run_sigchld_trap and maybe_set_sigchld_trap to see whether
+   or not a SIGCHLD trap handler reset SIGCHLD disposition to the default. */
+void
+set_impossible_sigchld_trap ()
+{
+  restore_default_signal (SIGCHLD);
+  change_signal (SIGCHLD, (char *)IMPOSSIBLE_TRAP_HANDLER);
+  sigmodes[SIGCHLD] &= ~SIG_TRAPPED;	/* maybe_set_sigchld_trap checks this */
+}
+
+/* Act as if we received SIGCHLD NCHILD times and increment
+   pending_traps[SIGCHLD] by that amount.  This allows us to still run the
+   SIGCHLD trap once for each exited child. */
+void
+queue_sigchld_trap (nchild)
+     int nchild;
+{
+  if (nchild > 0)
+    {
+      catch_flag = 1;
+      pending_traps[SIGCHLD] += nchild;
+      trapped_signal_received = SIGCHLD;
+    }
+}
 #endif /* JOB_CONTROL && SIGCHLD */
 
 void
@@ -350,6 +562,20 @@ set_debug_trap (command)
   set_signal (DEBUG_TRAP, command);
 }
 
+void
+set_error_trap (command)
+     char *command;
+{
+  set_signal (ERROR_TRAP, command);
+}
+
+void
+set_return_trap (command)
+     char *command;
+{
+  set_signal (RETURN_TRAP, command);
+}
+
 #ifdef INCLUDE_UNUSED
 void
 set_sigint_trap (command)
@@ -379,7 +605,7 @@ set_sigint_handler ()
   else if (interactive)	/* XXX - was interactive_shell */
     return (set_signal_handler (SIGINT, sigint_sighandler));
   else
-    return (set_signal_handler (SIGINT, termination_unwind_protect));
+    return (set_signal_handler (SIGINT, termsig_sighandler));
 }
 
 /* Return the correct handler for signal SIG according to the values in
@@ -402,7 +628,9 @@ set_signal (sig, string)
      int sig;
      char *string;
 {
-  if (sig == DEBUG_TRAP || sig == EXIT_TRAP)
+  sigset_t set, oset;
+
+  if (SPECIAL_TRAP (sig))
     {
       change_signal (sig, savestring (string));
       if (sig == EXIT_TRAP && interactive == 0)
@@ -421,17 +649,9 @@ set_signal (sig, string)
     {
       /* If we aren't sure of the original value, check it. */
       if (original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER)
-	{
-	  original_signals[sig] = (SigHandler *)set_signal_handler (sig, SIG_DFL);
-	  set_signal_handler (sig, original_signals[sig]);
-	}
-
-      /* Signals ignored on entry to the shell cannot be trapped or reset. */
+        GETORIGSIG (sig);
       if (original_signals[sig] == SIG_IGN)
-	{
-	  sigmodes[sig] |= SIG_HARD_IGNORE;
-	  return;
-	}
+	return;
     }
 
   /* Only change the system signal handler if SIG_NO_TRAP is not set.
@@ -440,9 +660,10 @@ set_signal (sig, string)
      environment in which it is safe to do so. */
   if ((sigmodes[sig] & SIG_NO_TRAP) == 0)
     {
-      set_signal_handler (sig, SIG_IGN);
+      BLOCK_SIGNAL (sig, set, oset);
       change_signal (sig, savestring (string));
       set_signal_handler (sig, trap_handler);
+      UNBLOCK_SIGNAL (oset);
     }
   else
     change_signal (sig, savestring (string));
@@ -479,25 +700,31 @@ change_signal (sig, value)
     sigmodes[sig] |= SIG_CHANGED;
 }
 
-#define GET_ORIGINAL_SIGNAL(sig) \
-  if (sig && sig < NSIG && original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) \
-    get_original_signal (sig)
-
-static void
+void
 get_original_signal (sig)
      int sig;
 {
   /* If we aren't sure the of the original value, then get it. */
-  if (original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER)
-    {
-      original_signals[sig] =
-	(SigHandler *) set_signal_handler (sig, SIG_DFL);
-      set_signal_handler (sig, original_signals[sig]);
+  if (sig > 0 && sig < NSIG && original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER)
+    GETORIGSIG (sig);
+}
 
-      /* Signals ignored on entry to the shell cannot be trapped. */
-      if (original_signals[sig] == SIG_IGN)
-	sigmodes[sig] |= SIG_HARD_IGNORE;
-    }
+void
+get_all_original_signals ()
+{
+  register int i;
+
+  for (i = 1; i < NSIG; i++)
+    GET_ORIGINAL_SIGNAL (i);
+}
+
+void
+set_original_signal (sig, handler)
+     int sig;
+     SigHandler *handler;
+{
+  if (sig > 0 && sig < NSIG && original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER)
+    SETORIGSIG (sig, handler);
 }
 
 /* Restore the default action for SIG; i.e., the action the shell
@@ -508,9 +735,10 @@ void
 restore_default_signal (sig)
      int sig;
 {
-  if (sig == DEBUG_TRAP || sig == EXIT_TRAP)
+  if (SPECIAL_TRAP (sig))
     {
-      if ((sig != DEBUG_TRAP) || (sigmodes[sig] & SIG_INPROGRESS) == 0)
+      if ((sig != DEBUG_TRAP && sig != ERROR_TRAP && sig != RETURN_TRAP) ||
+	  (sigmodes[sig] & SIG_INPROGRESS) == 0)
 	free_trap_command (sig);
       trap_list[sig] = (char *)NULL;
       sigmodes[sig] &= ~SIG_TRAPPED;
@@ -527,7 +755,11 @@ restore_default_signal (sig)
     return;
 
   /* If we aren't trapping this signal, don't bother doing anything else. */
-  if ((sigmodes[sig] & SIG_TRAPPED) == 0)
+  /* We special-case SIGCHLD and IMPOSSIBLE_TRAP_HANDLER (see above) as a
+     sentinel to determine whether or not disposition is reset to the default
+     while the trap handler is executing. */
+  if (((sigmodes[sig] & SIG_TRAPPED) == 0) &&
+      (sig != SIGCHLD || (sigmodes[sig] & SIG_INPROGRESS) == 0 || trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER))
     return;
 
   /* Only change the signal handler for SIG if it allows it. */
@@ -546,7 +778,7 @@ void
 ignore_signal (sig)
      int sig;
 {
-  if ((sig == EXIT_TRAP || sig == DEBUG_TRAP) && ((sigmodes[sig] & SIG_IGNORED) == 0))
+  if (SPECIAL_TRAP (sig) && ((sigmodes[sig] & SIG_IGNORED) == 0))
     {
       change_signal (sig, (char *)IGNORE_SIG);
       return;
@@ -578,9 +810,16 @@ int
 run_exit_trap ()
 {
   char *trap_command;
-  int code, old_exit_value;
+  int code, function_code, retval;
+#if defined (ARRAY_VARS)
+  ARRAY *ps;
+#endif
 
-  old_exit_value = last_command_exit_value;
+  trap_saved_exit_value = last_command_exit_value;
+#if defined (ARRAY_VARS)
+  ps = save_pipestatus_array ();
+#endif
+  function_code = 0;
 
   /* Run the trap only if signal 0 is trapped and not ignored, and we are not
      currently running in the trap handler (call to exit in the list of
@@ -592,20 +831,37 @@ run_exit_trap ()
       sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED;
       sigmodes[EXIT_TRAP] |= SIG_INPROGRESS;
 
-      code = setjmp (top_level);
+      retval = trap_saved_exit_value;
+      running_trap = 1;
+
+      code = setjmp_nosigs (top_level);
 
-      if (code == 0)
+      /* If we're in a function, make sure return longjmps come here, too. */
+      if (return_catch_flag)
+	function_code = setjmp_nosigs (return_catch);
+
+      if (code == 0 && function_code == 0)
 	{
 	  reset_parser ();
-	  parse_and_execute (trap_command, "exit trap", SEVAL_NONINT|SEVAL_NOHIST);
+	  parse_and_execute (trap_command, "exit trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE);
 	}
+      else if (code == ERREXIT)
+	retval = last_command_exit_value;
       else if (code == EXITPROG)
-	return (last_command_exit_value);
+	retval = last_command_exit_value;
+      else if (function_code != 0)
+        retval = return_catch_value;
       else
-	return (old_exit_value);
+	retval = trap_saved_exit_value;
+
+      running_trap = 0;
+      return retval;
     }
 
-  return (old_exit_value);
+#if defined (ARRAY_VARS)
+  restore_pipestatus_array (ps);
+#endif
+  return (trap_saved_exit_value);
 }
 
 void
@@ -615,21 +871,38 @@ run_trap_cleanup (sig)
   sigmodes[sig] &= ~(SIG_INPROGRESS|SIG_CHANGED);
 }
 
+#define RECURSIVE_SIG(s) (SPECIAL_TRAP(s) == 0)
+
 /* Run a trap command for SIG.  SIG is one of the signals the shell treats
-   specially. */
-static void
+   specially.  Returns the exit status of the executed trap command list. */
+static int
 _run_trap_internal (sig, tag)
      int sig;
      char *tag;
 {
   char *trap_command, *old_trap;
-  int old_exit_value, old_line_number, *token_state;
+  int trap_exit_value, *token_state;
+  volatile int save_return_catch_flag, function_code;
+  int flags;
+  procenv_t save_return_catch;
+  WORD_LIST *save_subst_varlist;
+  sh_parser_state_t pstate;
+#if defined (ARRAY_VARS)
+  ARRAY *ps;
+#endif
 
+  trap_exit_value = function_code = 0;
   /* Run the trap only if SIG is trapped and not ignored, and we are not
      currently executing in the trap handler. */
   if ((sigmodes[sig] & SIG_TRAPPED) && ((sigmodes[sig] & SIG_IGNORED) == 0) &&
       (trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER) &&
+#if 0
+      /* Uncomment this to allow some special signals to recursively execute
+	 trap handlers. */
+      (RECURSIVE_SIG (sig) || (sigmodes[sig] & SIG_INPROGRESS) == 0))
+#else
       ((sigmodes[sig] & SIG_INPROGRESS) == 0))
+#endif
     {
       old_trap = trap_list[sig];
       sigmodes[sig] |= SIG_INPROGRESS;
@@ -637,34 +910,147 @@ _run_trap_internal (sig, tag)
       trap_command =  savestring (old_trap);
 
       running_trap = sig + 1;
-      old_exit_value = last_command_exit_value;
-      /* Need to copy the value of line_number because parse_and_execute
-	 resets it to 1, and the trap command might want it. */
-      trap_line_number = line_number;
 
-      token_state = save_token_state ();
-      parse_and_execute (trap_command, tag, SEVAL_NONINT|SEVAL_NOHIST);
-      restore_token_state (token_state);
-      free (token_state);
+#if defined (ARRAY_VARS)
+      ps = save_pipestatus_array ();
+#endif
 
-      last_command_exit_value = old_exit_value;
+      save_parser_state (&pstate);
+      save_subst_varlist = subst_assign_varlist;
+      subst_assign_varlist = 0;
+
+#if defined (JOB_CONTROL)
+      if (sig != DEBUG_TRAP)	/* run_debug_trap does this */
+	save_pipeline (1);	/* XXX only provides one save level */
+#endif
+
+      /* If we're in a function, make sure return longjmps come here, too. */
+      save_return_catch_flag = return_catch_flag;
+      if (return_catch_flag)
+	{
+	  COPY_PROCENV (return_catch, save_return_catch);
+	  function_code = setjmp_nosigs (return_catch);
+	}
+
+      flags = SEVAL_NONINT|SEVAL_NOHIST;
+      if (sig != DEBUG_TRAP && sig != RETURN_TRAP && sig != ERROR_TRAP)
+	flags |= SEVAL_RESETLINE;
+      if (function_code == 0)
+	parse_and_execute (trap_command, tag, flags);
+
+      trap_exit_value = last_command_exit_value;
+
+#if defined (JOB_CONTROL)
+      if (sig != DEBUG_TRAP)	/* run_debug_trap does this */
+	restore_pipeline (1);
+#endif
+
+      subst_assign_varlist = save_subst_varlist;
+      restore_parser_state (&pstate);
+
+#if defined (ARRAY_VARS)
+      restore_pipestatus_array (ps);
+#endif
       running_trap = 0;
 
       sigmodes[sig] &= ~SIG_INPROGRESS;
 
       if (sigmodes[sig] & SIG_CHANGED)
 	{
-	  free (old_trap);
+#if 0
+	  /* Special traps like EXIT, DEBUG, RETURN are handled explicitly in
+	     the places where they can be changed using unwind-protects.  For
+	     example, look at execute_cmd.c:execute_function(). */
+	  if (SPECIAL_TRAP (sig) == 0)
+#endif
+	    free (old_trap);
 	  sigmodes[sig] &= ~SIG_CHANGED;
 	}
+
+      if (save_return_catch_flag)
+	{
+	  return_catch_flag = save_return_catch_flag;
+	  return_catch_value = trap_exit_value;
+	  COPY_PROCENV (save_return_catch, return_catch);
+	  if (function_code)
+	    longjmp (return_catch, 1);
+	}
     }
+
+  return trap_exit_value;
 }
 
-void
+int
 run_debug_trap ()
 {
-  if ((sigmodes[DEBUG_TRAP] & SIG_TRAPPED) && (sigmodes[DEBUG_TRAP] & SIG_INPROGRESS) == 0)
-    _run_trap_internal (DEBUG_TRAP, "debug trap");
+  int trap_exit_value;
+  pid_t save_pgrp;
+  int save_pipe[2];
+
+  /* XXX - question:  should the DEBUG trap inherit the RETURN trap? */
+  trap_exit_value = 0;
+  if ((sigmodes[DEBUG_TRAP] & SIG_TRAPPED) && ((sigmodes[DEBUG_TRAP] & SIG_IGNORED) == 0) && ((sigmodes[DEBUG_TRAP] & SIG_INPROGRESS) == 0))
+    {
+#if defined (JOB_CONTROL)
+      save_pgrp = pipeline_pgrp;
+      pipeline_pgrp = 0;
+      save_pipeline (1);
+#  if defined (PGRP_PIPE)
+      save_pgrp_pipe (save_pipe, 1);
+#  endif
+      stop_making_children ();
+#endif
+
+      trap_exit_value = _run_trap_internal (DEBUG_TRAP, "debug trap");
+
+#if defined (JOB_CONTROL)
+      pipeline_pgrp = save_pgrp;
+      restore_pipeline (1);
+#  if defined (PGRP_PIPE)
+      close_pgrp_pipe ();
+      restore_pgrp_pipe (save_pipe);
+#  endif
+      if (pipeline_pgrp > 0)
+	give_terminal_to (pipeline_pgrp, 1);
+      notify_and_cleanup ();
+#endif
+      
+#if defined (DEBUGGER)
+      /* If we're in the debugger and the DEBUG trap returns 2 while we're in
+	 a function or sourced script, we force a `return'. */
+      if (debugging_mode && trap_exit_value == 2 && return_catch_flag)
+	{
+	  return_catch_value = trap_exit_value;
+	  longjmp (return_catch, 1);
+	}
+#endif
+    }
+  return trap_exit_value;
+}
+
+void
+run_error_trap ()
+{
+  if ((sigmodes[ERROR_TRAP] & SIG_TRAPPED) && ((sigmodes[ERROR_TRAP] & SIG_IGNORED) == 0) && (sigmodes[ERROR_TRAP] & SIG_INPROGRESS) == 0)
+    _run_trap_internal (ERROR_TRAP, "error trap");
+}
+
+void
+run_return_trap ()
+{
+  int old_exit_value;
+
+#if 0
+  if ((sigmodes[DEBUG_TRAP] & SIG_TRAPPED) && (sigmodes[DEBUG_TRAP] & SIG_INPROGRESS))
+    return;
+#endif
+
+  if ((sigmodes[RETURN_TRAP] & SIG_TRAPPED) && ((sigmodes[RETURN_TRAP] & SIG_IGNORED) == 0) && (sigmodes[RETURN_TRAP] & SIG_INPROGRESS) == 0)
+    {
+      old_exit_value = last_command_exit_value;
+      _run_trap_internal (RETURN_TRAP, "return trap");
+      last_command_exit_value = old_exit_value;
+    }
 }
 
 /* Run a trap set on SIGINT.  This is called from throw_to_top_level (), and
@@ -675,30 +1061,44 @@ run_interrupt_trap ()
   _run_trap_internal (SIGINT, "interrupt trap");
 }
 
-#ifdef INCLUDE_UNUSED
 /* Free all the allocated strings in the list of traps and reset the trap
-   values to the default. */
+   values to the default.  Intended to be called from subshells that want
+   to complete work done by reset_signal_handlers upon execution of a
+   subsequent `trap' command that changes a signal's disposition.  We need
+   to make sure that we duplicate the behavior of
+   reset_or_restore_signal_handlers and not change the disposition of signals
+   that are set to be ignored. */
 void
 free_trap_strings ()
 {
   register int i;
 
-  for (i = 0; i < NSIG+1; i++)
+  for (i = 0; i < BASH_NSIG; i++)
     {
-      free_trap_command (i);
-      trap_list[i] = (char *)DEFAULT_SIG;
-      sigmodes[i] &= ~SIG_TRAPPED;
+      if (trap_list[i] != (char *)IGNORE_SIG)
+	free_trap_string (i);
     }
-  trap_list[DEBUG_TRAP] = trap_list[EXIT_TRAP] = (char *)NULL;
+  trap_list[DEBUG_TRAP] = trap_list[EXIT_TRAP] = trap_list[ERROR_TRAP] = trap_list[RETURN_TRAP] = (char *)NULL;
+}
+
+/* Free a trap command string associated with SIG without changing signal
+   disposition.  Intended to be called from free_trap_strings()  */
+static void
+free_trap_string (sig)
+     int sig;
+{
+  change_signal (sig, (char *)DEFAULT_SIG);
+  sigmodes[sig] &= ~SIG_TRAPPED;
 }
-#endif
 
-/* Reset the handler for SIG to the original value. */
+/* Reset the handler for SIG to the original value but leave the trap string
+   in place. */
 static void
 reset_signal (sig)
      int sig;
 {
   set_signal_handler (sig, original_signals[sig]);
+  sigmodes[sig] &= ~SIG_TRAPPED;
 }
 
 /* Set the handler signal SIG to the original and free any trap
@@ -714,17 +1114,21 @@ restore_signal (sig)
 
 static void
 reset_or_restore_signal_handlers (reset)
-     VFunction *reset;
+     sh_resetsig_func_t *reset;
 {
   register int i;
 
   /* Take care of the exit trap first */
   if (sigmodes[EXIT_TRAP] & SIG_TRAPPED)
     {
-      free_trap_command (EXIT_TRAP);
-      trap_list[EXIT_TRAP] = (char *)NULL;
       sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED;
+      if (reset != reset_signal)
+	{
+	  free_trap_command (EXIT_TRAP);
+	  trap_list[EXIT_TRAP] = (char *)NULL;
+	}
     }
+
   for (i = 1; i < NSIG; i++)
     {
       if (sigmodes[i] & SIG_TRAPPED)
@@ -737,8 +1141,24 @@ reset_or_restore_signal_handlers (reset)
       else if (sigmodes[i] & SIG_SPECIAL)
 	(*reset) (i);
     }
+
+  /* Command substitution and other child processes don't inherit the
+     debug, error, or return traps.  If we're in the debugger, and the
+     `functrace' or `errtrace' options have been set, then let command
+     substitutions inherit them.  Let command substitution inherit the
+     RETURN trap if we're in the debugger and tracing functions. */
+  if (function_trace_mode == 0)
+    {
+      sigmodes[DEBUG_TRAP] &= ~SIG_TRAPPED;
+      sigmodes[RETURN_TRAP] &= ~SIG_TRAPPED;
+    }
+  if (error_trace_mode == 0)
+    sigmodes[ERROR_TRAP] &= ~SIG_TRAPPED;
 }
 
+/* Reset trapped signals to their original values, but don't free the
+   trap strings.  Called by the command substitution code and other places
+   that create a "subshell environment". */
 void
 reset_signal_handlers ()
 {
@@ -755,7 +1175,7 @@ restore_original_signals ()
 }
 
 /* If a trap handler exists for signal SIG, then call it; otherwise just
-   return failure. */
+   return failure.  Returns 1 if it called the trap handler. */
 int
 maybe_call_trap_handler (sig)
      int sig;
@@ -774,6 +1194,9 @@ maybe_call_trap_handler (sig)
 	case DEBUG_TRAP:
 	  run_debug_trap ();
 	  break;
+	case ERROR_TRAP:
+	  run_error_trap ();
+	  break;
 	default:
 	  trap_handler (sig);
 	  break;
@@ -792,6 +1215,13 @@ signal_is_trapped (sig)
 }
 
 int
+signal_is_pending (sig)
+     int sig;
+{
+  return (pending_traps[sig]);
+}
+
+int
 signal_is_special (sig)
      int sig;
 {
@@ -805,10 +1235,31 @@ signal_is_ignored (sig)
   return (sigmodes[sig] & SIG_IGNORED);
 }
 
+int
+signal_is_hard_ignored (sig)
+     int sig;
+{
+  return (sigmodes[sig] & SIG_HARD_IGNORE);
+}
+
 void
-set_signal_ignored (sig)
+set_signal_hard_ignored (sig)
      int sig;
 {
   sigmodes[sig] |= SIG_HARD_IGNORE;
   original_signals[sig] = SIG_IGN;
 }
+
+void
+set_signal_ignored (sig)
+     int sig;
+{
+  original_signals[sig] = SIG_IGN;
+}
+
+int
+signal_in_progress (sig)
+     int sig;
+{
+  return (sigmodes[sig] & SIG_INPROGRESS);
+}