scallop 0.0.30

/* common.c - utility functions for all builtins */

/* Copyright (C) 1987-2024 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>
#include <stdarg.h>

#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 *buf)
{
  char *name;
  int line;

  name = get_name_for_error ();
  snprintf(buf, MAX_ERROR_LEN, "%s: ", name);

  if (interactive_shell == 0) {
    line = executing_line_number ();
    if (line != 0) {
      snprintf(buf + strlen(buf), MAX_ERROR_LEN - strlen(buf), _("line %d: "), line);
    }
  }

  if (this_command_name && *this_command_name)
    snprintf(buf + strlen(buf), MAX_ERROR_LEN - strlen(buf), "%s: ", this_command_name);
}

void
builtin_error (const char *format, ...)
{
  va_list args;
  char buf[MAX_ERROR_LEN] = "";

  builtin_error_prolog (&buf[0]);

  va_start (args, format);
  vsnprintf(buf + strlen(buf), MAX_ERROR_LEN - strlen(buf), format, args);
  va_end (args);

#if defined (BUILD_LIBRARY)
  scallop_error(buf);
#else
  fprintf (stderr, "%s\n", buf);
#endif
}

void
builtin_warning (const char *format, ...)
{
  va_list args;
  char buf[MAX_ERROR_LEN] = "";

  builtin_error_prolog (&buf[0]);
#if !defined (BUILD_LIBRARY)
  snprintf(buf + strlen(buf), MAX_ERROR_LEN - strlen(buf), _("warning: "));
#endif

  va_start (args, format);
  vsnprintf(buf + strlen(buf), MAX_ERROR_LEN - strlen(buf), format, args);
  va_end (args);

#if defined (BUILD_LIBRARY)
  scallop_warning(buf);
#else
  fprintf (stderr, "%s\n", buf);
#endif
}

/* Print a usage summary for the currently-executing builtin command. */
void
builtin_usage (void)
{
  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 (WORD_LIST *list, int fatal)
{
  if (list)
    {
      builtin_error (_("too many arguments"));
      top_level_cleanup ();
      set_exit_status (EX_BADUSAGE);
      /* for now, the caller determines whether this is a fatal error */
      if (interactive_shell == 0 && fatal)
	jump_to_top_level (EXITPROG);
      else
	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 (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 (const char *s)
{
  builtin_error (_("%s: option requires an argument"), s);
}

void
sh_neednumarg (const char *s)
{
  builtin_error (_("%s: numeric argument required"), s);
}

void
sh_notfound (const char *s)
{
  builtin_error (_("%s: not found"), s);
}

/* Function called when one of the builtin commands detects an invalid
   option. */
void
sh_invalidopt (const char *s)
{
  builtin_error (_("%s: invalid option"), s);
}

void
sh_invalidoptname (const char *s)
{
  builtin_error (_("%s: invalid option name"), s);
}

void
sh_invalidid (const char *s)
{
  builtin_error (_("`%s': not a valid identifier"), s);
}

void
sh_invalidnum (const 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 (const char *s)
{
  builtin_error (_("%s: invalid signal specification"), s);
}

void
sh_badpid (const char *s)
{
  builtin_error (_("`%s': not a pid or valid job spec"), s);
}

void
sh_readonly (const char *s)
{
  builtin_error (_("%s: readonly variable"), s);
}

void
sh_noassign (const char *s)
{
  internal_error (_("%s: cannot assign"), s);	/* XXX */
}

void
sh_erange (const char *s, const char *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 (const char *s)
{
  builtin_error (_("%s: no such job"), s);
}

void
sh_nojobs (const char *s)
{
  if (s)
    builtin_error (_("%s: no job control"), s);
  else
    builtin_error (_("no job control"));
}

void
sh_invalidjob (const char *s)
{
  builtin_error (_("%s: invalid job specification"), s);
}

#endif

#if defined (RESTRICTED_SHELL)
void
sh_restricted (const char *s)
{
  if (s)
    builtin_error (_("%s: restricted"), s);
  else
    builtin_error (_("restricted"));
}
#endif

void
sh_notbuiltin (const char *s)
{
  builtin_error (_("%s: not a shell builtin"), s);
}

void
sh_wrerror (void)
{
#if defined (DONT_REPORT_BROKEN_PIPE_WRITE_ERRORS) && defined (EPIPE)
  if (errno != EPIPE)
#endif /* DONT_REPORT_BROKEN_PIPE_WRITE_ERRORS && EPIPE */
  builtin_error ("%s: %s", _("write error"), strerror (errno));
}

void
sh_ttyerror (int set)
{
  if (set)
    builtin_error ("%s: %s", _("error setting terminal attributes"), strerror (errno));
  else
    builtin_error ("%s: %s", _("error getting terminal attributes"), strerror (errno));
}

int
sh_chkwrite (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 (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 (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 ((GENERIC_LIST *)list);
    }

  if (destructive)
    set_dollar_vars_changed ();

  invalidate_cached_quoted_dollar_at ();
}

void
shift_args (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 (void)
{
#if 0
  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);
#else
  return posparam_count;
#endif
}

static int changed_dollar_vars;

/* Have the dollar variables been reset to new values since we last
   checked? */
int
dollar_vars_changed (void)
{
  return (changed_dollar_vars);
}

void
set_dollar_vars_unchanged (void)
{
  changed_dollar_vars = 0;
}

void
set_dollar_vars_changed (void)
{
  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 (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 || (valid_number (arg, count) == 0))
	{
	  sh_neednumarg (list->word->word ? list->word->word : "`'");
	  if (fatal == 0)
	    return 0;
	  set_exit_status (EX_BADUSAGE);
	  /* fatal == 1: abort; fatal == 2: discard current command */
	  top_level_cleanup ();
	  jump_to_top_level ((fatal == 1) ? EXITPROG : DISCARD);
	}
      no_args (list->next, 0);
    }

  return (1);
}

/* Get an eight-bit status value from LIST */
int
get_exitstat (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, and haven't executed a shell
	 function from the trap action, the return builtin, when not given
	 any arguments, uses the value of $? before the trap ran. The business
	 about executing a shell function from the trap action is from POSIX
	 interp 1602 (10/2022). If given an argument, return uses it
	 unconditionally. 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 && trap_return_context == funcnest + sourcenest)
	return (trap_saved_exit_value);
      /* The same interp applies to the exit builtin. */
      if (this_shell_builtin == exit_builtin && running_trap > 0 && running_trap != DEBUG_TRAP+1 && trap_return_context == funcnest + sourcenest)
	return (trap_saved_exit_value);
      return (last_command_exit_value);
    }

  arg = list->word->word;
  if (arg == 0 || valid_number (arg, &sval) == 0)
    {
      sh_neednumarg (list->word->word ? list->word->word : "`'");
      return EX_USAGE;
    }
  no_args (list->next, 0);

  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 (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 (const 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: %s: %s: %s\n",
  	   (for_whom && *for_whom) ? for_whom : get_name_for_error (),
	   _("error retrieving current directory"),
	   _(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 (const 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 (const char *name, int flags)
{
  int i, match, job;
  size_t wl, cl;
  PROCESS *p;
  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 (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++;
  else
#if 1
    /* This could be builtin_error or sh_invalidjob() */
    builtin_warning (_("%s: job specification requires leading `%%'"), word);
#else
    /* TAG:bash-5.4 10/23/2024 */
    return (BAD_JOBSPEC);
#endif

  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 (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 (valid_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 (const 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 (const 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 (const 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 (const 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 (const struct builtin *sbp1, const struct builtin *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 (void)
{
  qsort (shell_builtins, num_shell_builtins, sizeof (struct builtin),
    (QSFUNC *)shell_builtin_compare);
}

#if !defined (HELP_BUILTIN)
void
builtin_help (void)
{
  printf ("%s: %s\n", this_command_name, _("help not available in this version"));
}
#endif

/* **************************************************************** */
/*								    */
/*	    Variable assignments during builtin commands	    */
/*								    */
/* **************************************************************** */

/* Assign NAME=VALUE, passing FLAGS to the assignment functions. */
SHELL_VAR *
builtin_bind_variable (char *name, char *value, int flags)
{
  SHELL_VAR *v;
  int vflags, bindflags;

#if defined (ARRAY_VARS)
  /* Callers are responsible for calling this with array references that have
     already undergone valid_array_reference checks (read, printf). */
  /* XXX - should we unconditionally set ASS_NOEXPAND if the shell
     compatibility level is > 52? */
  bindflags = flags | (array_expand_once ? ASS_NOEXPAND : 0) | ASS_ALLOWALLSUB;
  vflags = convert_assign_flags_to_validarray_flags (flags);
  vflags |= array_expand_once ? (VA_NOEXPAND|VA_ONEWORD) : 0;

  if (valid_array_reference (name, vflags) == 0)
    v = bind_variable (name, value, flags);
  else
    v = assign_array_element (name, value, bindflags, (array_eltstate_t *)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;
}

SHELL_VAR *
builtin_bind_var_to_int (char *name, intmax_t val, int flags)
{
  SHELL_VAR *v;

  v = bind_var_to_int (name, val, flags|ASS_ALLOWALLSUB);
  return v;
}

#if defined (ARRAY_VARS)
SHELL_VAR *
builtin_find_indexed_array (char *array_name, int flags)
{
  SHELL_VAR *entry;

  if ((flags & 2) && valid_identifier (array_name) == 0)
    {
      sh_invalidid (array_name);
      return (SHELL_VAR *)NULL;
    }

  entry = find_or_make_array_variable (array_name, 1);
  /* With flags argument & 1, find_or_make_array_variable checks for readonly
     and noassign variables and prints error messages. */
  if (entry == 0)
    return entry;
  else if (array_p (entry) == 0)
    {
      builtin_error (_("%s: not an indexed array"), array_name);
      return (SHELL_VAR *)NULL;
    }
  else if (invisible_p (entry))
    VUNSETATTR (entry, att_invisible);	/* no longer invisible */

  if (flags & 1)
    array_flush (array_cell (entry));

  return entry;
}
#endif /* ARRAY_VARS */	

/* Like check_unbind_variable, but for use by builtins (only matters for
   error messages). */
int
builtin_unbind_variable (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));
}

int
builtin_arrayref_flags (WORD_DESC *w, int baseflags)
{
  int vflags;

  vflags = baseflags;

  /* Don't require array_expand_once if we have an argument that's already
     passed through valid_array_reference and been expanded once. That
     doesn't protect it from normal expansions like word splitting, so
     proper quoting is still required. */
  if (w->flags & W_ARRAYREF)
    vflags |= VA_ONEWORD|VA_NOEXPAND;

#  if 0
  /* This is a little sketchier but handles quoted arguments. */
  if (array_expand_once && (t =  strchr (w->word, '[')) && t[strlen(t) - 1] == ']')
    vflags |= VA_ONEWORD|VA_NOEXPAND;
#  endif

  return vflags;
}

/* **************************************************************** */
/*								    */
/*	    External interface to manipulate shell options	    */
/*								    */
/* **************************************************************** */

#if defined (ARRAY_VARS)
int
set_expand_once (int nval, int uwp)
{
  int oa;

  oa = array_expand_once;
  if (shell_compatibility_level > 51)	/* XXX - internal */
    {
      if (uwp)
	unwind_protect_int (array_expand_once);
      array_expand_once = nval;
    }
  return oa;
}
#endif

/* Register a given array of new builtins into the internal list. */
int
register_builtins (struct builtin **new_builtins, size_t num_new_builtins)
{
  size_t total, size, replaced;
  struct builtin *new_shell_builtins;

  total = num_shell_builtins + num_new_builtins;
  size = (total + 1) * sizeof (struct builtin);

  new_shell_builtins = (struct builtin *)xmalloc (size);
  FASTCOPY ((char *)shell_builtins, (char *)new_shell_builtins,
    num_shell_builtins * sizeof (struct builtin));
  for (replaced = 0; replaced < num_new_builtins; replaced++)
    FASTCOPY ((char *)new_builtins[replaced],
    (char *)&new_shell_builtins[num_shell_builtins + replaced],
    sizeof (struct builtin));

  new_shell_builtins[total].name = (char *)0;
  new_shell_builtins[total].function = (sh_builtin_func_t *)0;
  new_shell_builtins[total].flags = 0;

  if (shell_builtins != static_shell_builtins)
    free (shell_builtins);

  shell_builtins = new_shell_builtins;
  num_shell_builtins = total;
  initialize_shell_builtins ();

  return (EXECUTION_SUCCESS);
}