Adding upstream version 5.1.upstream/5.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1017 insertions, 0 deletions

diff --git a/builtins/common.c b/builtins/common.c
new file mode 100644
index 0000000..3c9ac49
--- /dev/null
+++ b/builtins/common.c
@@ -0,0 +1,1017 @@
+/* common.c - utility functions for all builtins */
+
+/* Copyright (C) 1987-2020 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 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.
+
+   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>
+
+#if defined (HAVE_UNISTD_H)
+#  ifdef _MINIX
+#    include <sys/types.h>
+#  endif
+#  include <unistd.h>
+#endif
+
+#include <stdio.h>
+#include <chartypes.h>
+#include "../bashtypes.h"
+#include "posixstat.h"
+#include <signal.h>
+
+#include <errno.h>
+
+#if defined (PREFER_STDARG)
+#  include <stdarg.h>
+#else
+#  include <varargs.h>
+#endif
+
+#include "../bashansi.h"
+#include "../bashintl.h"
+
+#define NEED_FPURGE_DECL
+
+#include "../shell.h"
+#include "maxpath.h"
+#include "../flags.h"
+#include "../parser.h"
+#include "../jobs.h"
+#include "../builtins.h"
+#include "../input.h"
+#include "../execute_cmd.h"
+#include "../trap.h"
+#include "bashgetopt.h"
+#include "common.h"
+#include "builtext.h"
+#include <tilde/tilde.h>
+
+#if defined (HISTORY)
+#  include "../bashhist.h"
+#endif
+
+#if !defined (errno)
+extern int errno;   
+#endif /* !errno */
+
+extern const char * const bash_getcwd_errstr;
+
+/* Used by some builtins and the mainline code. */
+sh_builtin_func_t *last_shell_builtin = (sh_builtin_func_t *)NULL;
+sh_builtin_func_t *this_shell_builtin = (sh_builtin_func_t *)NULL;
+
+/* **************************************************************** */
+/*								    */
+/*	     Error reporting, usage, and option processing	    */
+/*								    */
+/* **************************************************************** */
+
+/* This is a lot like report_error (), but it is for shell builtins
+   instead of shell control structures, and it won't ever exit the
+   shell. */
+
+static void
+builtin_error_prolog ()
+{
+  char *name;
+
+  name = get_name_for_error ();
+  fprintf (stderr, "%s: ", name);
+
+  if (interactive_shell == 0)
+    fprintf (stderr, _("line %d: "), executing_line_number ());
+
+  if (this_command_name && *this_command_name)
+    fprintf (stderr, "%s: ", this_command_name);
+}
+
+void
+#if defined (PREFER_STDARG)
+builtin_error (const char *format, ...)
+#else
+builtin_error (format, va_alist)
+     const char *format;
+     va_dcl
+#endif
+{
+  va_list args;
+
+  builtin_error_prolog ();
+
+  SH_VA_START (args, format);
+
+  vfprintf (stderr, format, args);
+  va_end (args);
+  fprintf (stderr, "\n");
+}
+
+void
+#if defined (PREFER_STDARG)
+builtin_warning (const char *format, ...)
+#else
+builtin_warning (format, va_alist)
+     const char *format;
+     va_dcl
+#endif
+{
+  va_list args;
+
+  builtin_error_prolog ();
+  fprintf (stderr, _("warning: "));
+
+  SH_VA_START (args, format);
+
+  vfprintf (stderr, format, args);
+  va_end (args);
+  fprintf (stderr, "\n");
+}
+
+/* Print a usage summary for the currently-executing builtin command. */
+void
+builtin_usage ()
+{
+  if (this_command_name && *this_command_name)
+    fprintf (stderr, _("%s: usage: "), this_command_name);
+  fprintf (stderr, "%s\n", _(current_builtin->short_doc));
+  fflush (stderr);
+}
+
+/* Return if LIST is NULL else barf and jump to top_level.  Used by some
+   builtins that do not accept arguments. */
+void
+no_args (list)
+     WORD_LIST *list;
+{
+  if (list)
+    {
+      builtin_error (_("too many arguments"));
+      top_level_cleanup ();
+      jump_to_top_level (DISCARD);
+    }
+}
+
+/* Check that no options were given to the currently-executing builtin,
+   and return 0 if there were options. */
+int
+no_options (list)
+     WORD_LIST *list;
+{
+  int opt;
+
+  reset_internal_getopt ();
+  if ((opt = internal_getopt (list, "")) != -1)
+    {
+      if (opt == GETOPT_HELP)
+	{
+	  builtin_help ();
+	  return (2);
+	}
+      builtin_usage ();
+      return (1);
+    }
+  return (0);
+}
+
+void
+sh_needarg (s)
+     char *s;
+{
+  builtin_error (_("%s: option requires an argument"), s);
+}
+
+void
+sh_neednumarg (s)
+     char *s;
+{
+  builtin_error (_("%s: numeric argument required"), s);
+}
+
+void
+sh_notfound (s)
+     char *s;
+{
+  builtin_error (_("%s: not found"), s);
+}
+
+/* Function called when one of the builtin commands detects an invalid
+   option. */
+void
+sh_invalidopt (s)
+     char *s;
+{
+  builtin_error (_("%s: invalid option"), s);
+}
+
+void
+sh_invalidoptname (s)
+     char *s;
+{
+  builtin_error (_("%s: invalid option name"), s);
+}
+
+void
+sh_invalidid (s)
+     char *s;
+{
+  builtin_error (_("`%s': not a valid identifier"), s);
+}
+
+void
+sh_invalidnum (s)
+     char *s;
+{
+  char *msg;
+
+  if (*s == '0' && isdigit ((unsigned char)s[1]))
+    msg = _("invalid octal number");
+  else if (*s == '0' && s[1] == 'x')
+    msg = _("invalid hex number");
+  else
+    msg = _("invalid number");
+  builtin_error ("%s: %s", s, msg);
+}
+
+void
+sh_invalidsig (s)
+     char *s;
+{
+  builtin_error (_("%s: invalid signal specification"), s);
+}
+
+void
+sh_badpid (s)
+     char *s;
+{
+  builtin_error (_("`%s': not a pid or valid job spec"), s);
+}
+
+void
+sh_readonly (s)
+     const char *s;
+{
+  builtin_error (_("%s: readonly variable"), s);
+}
+
+void
+sh_erange (s, desc)
+     char *s, *desc;
+{
+  if (s)
+    builtin_error (_("%s: %s out of range"), s, desc ? desc : _("argument"));
+  else
+    builtin_error (_("%s out of range"), desc ? desc : _("argument"));
+}
+
+#if defined (JOB_CONTROL)
+void
+sh_badjob (s)
+     char *s;
+{
+  builtin_error (_("%s: no such job"), s);
+}
+
+void
+sh_nojobs (s)
+     char *s;
+{
+  if (s)
+    builtin_error (_("%s: no job control"), s);
+  else
+    builtin_error (_("no job control"));
+}
+#endif
+
+#if defined (RESTRICTED_SHELL)
+void
+sh_restricted (s)
+     char *s;
+{
+  if (s)
+    builtin_error (_("%s: restricted"), s);
+  else
+    builtin_error (_("restricted"));
+}
+#endif
+
+void
+sh_notbuiltin (s)
+     char *s;
+{
+  builtin_error (_("%s: not a shell builtin"), s);
+}
+
+void
+sh_wrerror ()
+{
+#if defined (DONT_REPORT_BROKEN_PIPE_WRITE_ERRORS) && defined (EPIPE)
+  if (errno != EPIPE)
+#endif /* DONT_REPORT_BROKEN_PIPE_WRITE_ERRORS && EPIPE */
+  builtin_error (_("write error: %s"), strerror (errno));
+}
+
+void
+sh_ttyerror (set)
+     int set;
+{
+  if (set)
+    builtin_error (_("error setting terminal attributes: %s"), strerror (errno));
+  else
+    builtin_error (_("error getting terminal attributes: %s"), strerror (errno));
+}
+
+int
+sh_chkwrite (s)
+     int s;
+{
+  QUIT;
+  fflush (stdout);
+  QUIT;
+  if (ferror (stdout))
+    {
+      sh_wrerror ();
+      fpurge (stdout);
+      clearerr (stdout);
+      return (EXECUTION_FAILURE);
+    }
+  return (s);
+}
+
+/* **************************************************************** */
+/*								    */
+/*	     Shell positional parameter manipulation		    */
+/*								    */
+/* **************************************************************** */
+
+/* Convert a WORD_LIST into a C-style argv.  Return the number of elements
+   in the list in *IP, if IP is non-null.  A convenience function for
+   loadable builtins; also used by `test'. */
+char **
+make_builtin_argv (list, ip)
+     WORD_LIST *list;
+     int *ip;
+{
+  char **argv;
+
+  argv = strvec_from_word_list (list, 0, 1, ip);
+  argv[0] = this_command_name;
+  return argv;
+}
+
+/* Remember LIST in $1 ... $9, and REST_OF_ARGS.  If DESTRUCTIVE is
+   non-zero, then discard whatever the existing arguments are, else
+   only discard the ones that are to be replaced.  Set POSPARAM_COUNT
+   to the number of args assigned (length of LIST). */
+void
+remember_args (list, destructive)
+     WORD_LIST *list;
+     int destructive;
+{
+  register int i;
+
+  posparam_count = 0;
+
+  for (i = 1; i < 10; i++)
+    {
+      if ((destructive || list) && dollar_vars[i])
+	{
+	  free (dollar_vars[i]);
+	  dollar_vars[i] = (char *)NULL;
+	}
+
+      if (list)
+	{
+	  dollar_vars[posparam_count = i] = savestring (list->word->word);
+	  list = list->next;
+	}
+    }
+
+  /* If arguments remain, assign them to REST_OF_ARGS.
+     Note that copy_word_list (NULL) returns NULL, and
+     that dispose_words (NULL) does nothing. */
+  if (destructive || list)
+    {
+      dispose_words (rest_of_args);
+      rest_of_args = copy_word_list (list);
+      posparam_count += list_length (list);
+    }
+
+  if (destructive)
+    set_dollar_vars_changed ();
+
+  invalidate_cached_quoted_dollar_at ();
+}
+
+void
+shift_args (times)
+     int times;
+{
+  WORD_LIST *temp;
+  int count;
+
+  if (times <= 0)		/* caller should check */
+    return;
+
+  while (times-- > 0)
+    {
+      if (dollar_vars[1])
+	free (dollar_vars[1]);
+
+      for (count = 1; count < 9; count++)
+	dollar_vars[count] = dollar_vars[count + 1];
+
+      if (rest_of_args)
+	{
+	  temp = rest_of_args;
+	  dollar_vars[9] = savestring (temp->word->word);
+	  rest_of_args = rest_of_args->next;
+	  temp->next = (WORD_LIST *)NULL;
+	  dispose_words (temp);
+	}
+      else
+	dollar_vars[9] = (char *)NULL;
+
+      posparam_count--;
+    }
+}
+
+int
+number_of_args ()
+{
+#ifdef DEBUG
+  register WORD_LIST *list;
+  int n;
+
+  for (n = 0; n < 9 && dollar_vars[n+1]; n++)
+    ;
+  for (list = rest_of_args; list; list = list->next)
+    n++;
+
+if (n != posparam_count)
+  itrace("number_of_args: n (%d) != posparam_count (%d)", n, posparam_count);
+#endif
+
+  return posparam_count;
+}
+
+static int changed_dollar_vars;
+
+/* Have the dollar variables been reset to new values since we last
+   checked? */
+int
+dollar_vars_changed ()
+{
+  return (changed_dollar_vars);
+}
+
+void
+set_dollar_vars_unchanged ()
+{
+  changed_dollar_vars = 0;
+}
+
+void
+set_dollar_vars_changed ()
+{
+  if (variable_context)
+    changed_dollar_vars |= ARGS_FUNC;
+  else if (this_shell_builtin == set_builtin)
+    changed_dollar_vars |= ARGS_SETBLTIN;
+  else
+    changed_dollar_vars |= ARGS_INVOC;
+}
+
+/* **************************************************************** */
+/*								    */
+/*		Validating numeric input and arguments		    */
+/*								    */
+/* **************************************************************** */
+
+/* Read a numeric arg for this_command_name, the name of the shell builtin
+   that wants it.  LIST is the word list that the arg is to come from.
+   Accept only the numeric argument; report an error if other arguments
+   follow.  If FATAL is 1, call throw_to_top_level, which exits the
+   shell; if it's 2, call jump_to_top_level (DISCARD), which aborts the
+   current command; if FATAL is 0, return an indication of an invalid
+   number by setting *NUMOK == 0 and return -1. */
+int
+get_numeric_arg (list, fatal, count)
+     WORD_LIST *list;
+     int fatal;
+     intmax_t *count;
+{
+  char *arg;
+
+  if (count)
+    *count = 1;
+
+  if (list && list->word && ISOPTION (list->word->word, '-'))
+    list = list->next;
+
+  if (list)
+    {
+      arg = list->word->word;
+      if (arg == 0 || (legal_number (arg, count) == 0))
+	{
+	  sh_neednumarg (list->word->word ? list->word->word : "`'");
+	  if (fatal == 0)
+	    return 0;
+	  else if (fatal == 1)		/* fatal == 1; abort */
+	    throw_to_top_level ();
+	  else				/* fatal == 2; discard current command */
+	    {
+	      top_level_cleanup ();
+	      jump_to_top_level (DISCARD);
+	    }
+	}
+      no_args (list->next);
+    }
+
+  return (1);
+}
+
+/* Get an eight-bit status value from LIST */
+int
+get_exitstat (list)
+     WORD_LIST *list;
+{
+  int status;
+  intmax_t sval;
+  char *arg;
+
+  if (list && list->word && ISOPTION (list->word->word, '-'))
+    list = list->next;
+
+  if (list == 0)
+    {
+      /* If we're not running the DEBUG trap, the return builtin, when not
+	 given any arguments, uses the value of $? before the trap ran.  If
+	 given an argument, return uses it.  This means that the trap can't
+	 change $?.  The DEBUG trap gets to change $?, though, since that is
+	 part of its reason for existing, and because the extended debug mode
+	 does things with the return value. */
+      if (this_shell_builtin == return_builtin && running_trap > 0 && running_trap != DEBUG_TRAP+1)
+	return (trap_saved_exit_value);
+      return (last_command_exit_value);
+    }
+
+  arg = list->word->word;
+  if (arg == 0 || legal_number (arg, &sval) == 0)
+    {
+      sh_neednumarg (list->word->word ? list->word->word : "`'");
+      return EX_BADUSAGE;
+    }
+  no_args (list->next);
+
+  status = sval & 255;
+  return status;
+}
+
+/* Return the octal number parsed from STRING, or -1 to indicate
+   that the string contained a bad number. */
+int
+read_octal (string)
+     char *string;
+{
+  int result, digits;
+
+  result = digits = 0;
+  while (*string && ISOCTAL (*string))
+    {
+      digits++;
+      result = (result * 8) + (*string++ - '0');
+      if (result > 07777)
+	return -1;
+    }
+
+  if (digits == 0 || *string)
+    result = -1;
+
+  return (result);
+}
+
+/* **************************************************************** */
+/*								    */
+/*	     Manipulating the current working directory		    */
+/*								    */
+/* **************************************************************** */
+
+/* Return a consed string which is the current working directory.
+   FOR_WHOM is the name of the caller for error printing.  */
+char *the_current_working_directory = (char *)NULL;
+
+char *
+get_working_directory (for_whom)
+     char *for_whom;
+{
+  if (no_symbolic_links)
+    {
+      FREE (the_current_working_directory);
+      the_current_working_directory = (char *)NULL;
+    }
+
+  if (the_current_working_directory == 0)
+    {
+#if defined (GETCWD_BROKEN)
+      the_current_working_directory = getcwd (0, PATH_MAX);
+#else
+      the_current_working_directory = getcwd (0, 0);
+#endif
+      if (the_current_working_directory == 0)
+	{
+	  fprintf (stderr, _("%s: error retrieving current directory: %s: %s\n"),
+		   (for_whom && *for_whom) ? for_whom : get_name_for_error (),
+		   _(bash_getcwd_errstr), strerror (errno));
+	  return (char *)NULL;
+	}
+    }
+
+  return (savestring (the_current_working_directory));
+}
+
+/* Make NAME our internal idea of the current working directory. */
+void
+set_working_directory (name)
+     char *name;
+{
+  FREE (the_current_working_directory);
+  the_current_working_directory = savestring (name);
+}
+
+/* **************************************************************** */
+/*								    */
+/*	     	Job control support functions			    */
+/*								    */
+/* **************************************************************** */
+
+#if defined (JOB_CONTROL)
+int
+get_job_by_name (name, flags)
+     const char *name;
+     int flags;
+{
+  register int i, wl, cl, match, job;
+  register PROCESS *p;
+  register JOB *j;
+
+  job = NO_JOB;
+  wl = strlen (name);
+  for (i = js.j_jobslots - 1; i >= 0; i--)
+    {
+      j = get_job_by_jid (i);
+      if (j == 0 || ((flags & JM_STOPPED) && J_JOBSTATE(j) != JSTOPPED))
+        continue;
+
+      p = j->pipe;
+      do
+        {
+	  if (flags & JM_EXACT)
+	    {
+	      cl = strlen (p->command);
+	      match = STREQN (p->command, name, cl);
+	    }
+	  else if (flags & JM_SUBSTRING)
+	    match = strcasestr (p->command, name) != (char *)0;
+	  else
+	    match = STREQN (p->command, name, wl);
+
+	  if (match == 0)
+	    {
+	      p = p->next;
+	      continue;
+	    }
+	  else if (flags & JM_FIRSTMATCH)
+	    return i;		/* return first match */
+	  else if (job != NO_JOB)
+	    {
+	      if (this_shell_builtin)
+	        builtin_error (_("%s: ambiguous job spec"), name);
+	      else
+	        internal_error (_("%s: ambiguous job spec"), name);
+	      return (DUP_JOB);
+	    }
+	  else
+	    job = i;
+        }
+      while (p != j->pipe);
+    }
+
+  return (job);
+}
+
+/* Return the job spec found in LIST. */
+int
+get_job_spec (list)
+     WORD_LIST *list;
+{
+  register char *word;
+  int job, jflags;
+
+  if (list == 0)
+    return (js.j_current);
+
+  word = list->word->word;
+
+  if (*word == '\0')
+    return (NO_JOB);
+
+  if (*word == '%')
+    word++;
+
+  if (DIGIT (*word) && all_digits (word))
+    {
+      job = atoi (word);
+      return ((job < 0 || job > js.j_jobslots) ? NO_JOB : job - 1);
+    }
+
+  jflags = 0;
+  switch (*word)
+    {
+    case 0:
+    case '%':
+    case '+':
+      return (js.j_current);
+
+    case '-':
+      return (js.j_previous);
+
+    case '?':			/* Substring search requested. */
+      jflags |= JM_SUBSTRING;
+      word++;
+      /* FALLTHROUGH */
+
+    default:
+      return get_job_by_name (word, jflags);
+    }
+}
+#endif /* JOB_CONTROL */
+
+/*
+ * NOTE:  `kill' calls this function with forcecols == 0
+ */
+int
+display_signal_list (list, forcecols)
+     WORD_LIST *list;
+     int forcecols;
+{
+  register int i, column;
+  char *name;
+  int result, signum, dflags;
+  intmax_t lsignum;
+
+  result = EXECUTION_SUCCESS;
+  if (!list)
+    {
+      for (i = 1, column = 0; i < NSIG; i++)
+	{
+	  name = signal_name (i);
+	  if (STREQN (name, "SIGJUNK", 7) || STREQN (name, "Unknown", 7))
+	    continue;
+
+	  if (posixly_correct && !forcecols)
+	    {
+	      /* This is for the kill builtin.  POSIX.2 says the signal names
+		 are displayed without the `SIG' prefix. */
+	      if (STREQN (name, "SIG", 3))
+		name += 3;
+	      printf ("%s%s", name, (i == NSIG - 1) ? "" : " ");
+	    }
+	  else
+	    {
+	      printf ("%2d) %s", i, name);
+
+	      if (++column < 5)
+		printf ("\t");
+	      else
+		{
+		  printf ("\n");
+		  column = 0;
+		}
+	    }
+	}
+
+      if ((posixly_correct && !forcecols) || column != 0)
+	printf ("\n");
+      return result;
+    }
+
+  /* List individual signal names or numbers. */
+  while (list)
+    {
+      if (legal_number (list->word->word, &lsignum))
+	{
+	  /* This is specified by Posix.2 so that exit statuses can be
+	     mapped into signal numbers. */
+	  if (lsignum > 128)
+	    lsignum -= 128;
+	  if (lsignum < 0 || lsignum >= NSIG)
+	    {
+	      sh_invalidsig (list->word->word);
+	      result = EXECUTION_FAILURE;
+	      list = list->next;
+	      continue;
+	    }
+
+	  signum = lsignum;
+	  name = signal_name (signum);
+	  if (STREQN (name, "SIGJUNK", 7) || STREQN (name, "Unknown", 7))
+	    {
+	      list = list->next;
+	      continue;
+	    }
+	  /* POSIX.2 says that `kill -l signum' prints the signal name without
+	     the `SIG' prefix. */
+	  printf ("%s\n", (this_shell_builtin == kill_builtin && signum > 0) ? name + 3 : name);
+	}
+      else
+	{
+	  dflags = DSIG_NOCASE;
+	  if (posixly_correct == 0 || this_shell_builtin != kill_builtin)
+	    dflags |= DSIG_SIGPREFIX;
+	  signum = decode_signal (list->word->word, dflags);
+	  if (signum == NO_SIG)
+	    {
+	      sh_invalidsig (list->word->word);
+	      result = EXECUTION_FAILURE;
+	      list = list->next;
+	      continue;
+	    }
+	  printf ("%d\n", signum);
+	}
+      list = list->next;
+    }
+  return (result);
+}
+
+/* **************************************************************** */
+/*								    */
+/*	    Finding builtin commands and their functions	    */
+/*								    */
+/* **************************************************************** */
+
+/* Perform a binary search and return the address of the builtin function
+   whose name is NAME.  If the function couldn't be found, or the builtin
+   is disabled or has no function associated with it, return NULL.
+   Return the address of the builtin.
+   DISABLED_OKAY means find it even if the builtin is disabled. */
+struct builtin *
+builtin_address_internal (name, disabled_okay)
+     char *name;
+     int disabled_okay;
+{
+  int hi, lo, mid, j;
+
+  hi = num_shell_builtins - 1;
+  lo = 0;
+
+  while (lo <= hi)
+    {
+      mid = (lo + hi) / 2;
+
+      j = shell_builtins[mid].name[0] - name[0];
+
+      if (j == 0)
+	j = strcmp (shell_builtins[mid].name, name);
+
+      if (j == 0)
+	{
+	  /* It must have a function pointer.  It must be enabled, or we
+	     must have explicitly allowed disabled functions to be found,
+	     and it must not have been deleted. */
+	  if (shell_builtins[mid].function &&
+	      ((shell_builtins[mid].flags & BUILTIN_DELETED) == 0) &&
+	      ((shell_builtins[mid].flags & BUILTIN_ENABLED) || disabled_okay))
+	    return (&shell_builtins[mid]);
+	  else
+	    return ((struct builtin *)NULL);
+	}
+      if (j > 0)
+	hi = mid - 1;
+      else
+	lo = mid + 1;
+    }
+  return ((struct builtin *)NULL);
+}
+
+/* Return the pointer to the function implementing builtin command NAME. */
+sh_builtin_func_t *
+find_shell_builtin (name)
+     char *name;
+{
+  current_builtin = builtin_address_internal (name, 0);
+  return (current_builtin ? current_builtin->function : (sh_builtin_func_t *)NULL);
+}
+
+/* Return the address of builtin with NAME, whether it is enabled or not. */
+sh_builtin_func_t *
+builtin_address (name)
+     char *name;
+{
+  current_builtin = builtin_address_internal (name, 1);
+  return (current_builtin ? current_builtin->function : (sh_builtin_func_t *)NULL);
+}
+
+/* Return the function implementing the builtin NAME, but only if it is a
+   POSIX.2 special builtin. */
+sh_builtin_func_t *
+find_special_builtin (name)
+     char *name;
+{
+  current_builtin = builtin_address_internal (name, 0);
+  return ((current_builtin && (current_builtin->flags & SPECIAL_BUILTIN)) ?
+  			current_builtin->function :
+  			(sh_builtin_func_t *)NULL);
+}
+  
+static int
+shell_builtin_compare (sbp1, sbp2)
+     struct builtin *sbp1, *sbp2;
+{
+  int result;
+
+  if ((result = sbp1->name[0] - sbp2->name[0]) == 0)
+    result = strcmp (sbp1->name, sbp2->name);
+
+  return (result);
+}
+
+/* Sort the table of shell builtins so that the binary search will work
+   in find_shell_builtin. */
+void
+initialize_shell_builtins ()
+{
+  qsort (shell_builtins, num_shell_builtins, sizeof (struct builtin),
+    (QSFUNC *)shell_builtin_compare);
+}
+
+#if !defined (HELP_BUILTIN)
+void
+builtin_help ()
+{
+  printf ("%s: %s\n", this_command_name, _("help not available in this version"));
+}
+#endif
+
+/* **************************************************************** */
+/*								    */
+/*	    Variable assignments during builtin commands	    */
+/*								    */
+/* **************************************************************** */
+
+SHELL_VAR *
+builtin_bind_variable (name, value, flags)
+     char *name;
+     char *value;
+     int flags;
+{
+  SHELL_VAR *v;
+
+#if defined (ARRAY_VARS)
+  if (valid_array_reference (name, assoc_expand_once ? (VA_NOEXPAND|VA_ONEWORD) : 0) == 0)
+    v = bind_variable (name, value, flags);
+  else
+    v = assign_array_element (name, value, flags | (assoc_expand_once ? ASS_NOEXPAND : 0));
+#else /* !ARRAY_VARS */
+  v = bind_variable (name, value, flags);
+#endif /* !ARRAY_VARS */
+
+  if (v && readonly_p (v) == 0 && noassign_p (v) == 0)
+    VUNSETATTR (v, att_invisible);
+
+  return v;
+}
+
+/* Like check_unbind_variable, but for use by builtins (only matters for
+   error messages). */
+int
+builtin_unbind_variable (vname)
+     const char *vname;
+{
+  SHELL_VAR *v;
+
+  v = find_variable (vname);
+  if (v && readonly_p (v))
+    {
+      builtin_error (_("%s: cannot unset: readonly %s"), vname, "variable");
+      return -2;
+    }
+  else if (v && non_unsettable_p (v))
+    {
+      builtin_error (_("%s: cannot unset"), vname);
+      return -2;
+    }
+  return (unbind_variable (vname));
+}