This file is set.def, from which is created set.c.
It implements the "set" and "unset" builtins in Bash.

Copyright (C) 1987, 1989, 1991 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 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.

$PRODUCES set.c

#include <config.h>

#if defined (HAVE_UNISTD_H)
#  ifdef _MINIX
#    include <sys/types.h>
#  endif
#  include <unistd.h>
#endif

#include <stdio.h>

#include "../bashansi.h"

#include "../shell.h"
#include "../flags.h"
#include "common.h"
#include "bashgetopt.h"

#if defined (READLINE)
#  include "../input.h"
#  include "../bashline.h"
#  include <readline/readline.h>
#endif

#if defined (HISTORY)
#  include "../bashhist.h"
#endif

extern int interactive;
extern int noclobber, posixly_correct, ignoreeof, eof_encountered_limit;
#if defined (READLINE)
extern int no_line_editing;
#endif /* READLINE */

$BUILTIN set
$FUNCTION set_builtin
$SHORT_DOC set [--abefhkmnptuvxBCHP] [-o option] [arg ...]
    -a  Mark variables which are modified or created for export.
    -b  Notify of job termination immediately.
    -e  Exit immediately if a command exits with a non-zero status.
    -f  Disable file name generation (globbing).
    -h  Remember the location of commands as they are looked up.
    -i  Force the shell to be an "interactive" one.  Interactive shells
        always read `~/.bashrc' on startup.
    -k  All assignment arguments are placed in the environment for a
        command, not just those that precede the command name.
    -m  Job control is enabled.
    -n  Read commands but do not execute them.
    -o option-name
        Set the variable corresponding to option-name:
            allexport    same as -a
            braceexpand  same as -B
#if defined (READLINE)
            emacs        use an emacs-style line editing interface
#endif /* READLINE */
            errexit      same as -e
            hashall      same as -h
#if defined (BANG_HISTORY)
            histexpand   same as -H
#endif /* BANG_HISTORY */
#if defined (HISTORY)
            history      enable command history
#endif
            ignoreeof    the shell will not exit upon reading EOF
            interactive-comments
                         allow comments to appear in interactive commands
            keyword      same as -k
            monitor      same as -m
            noclobber    same as -C
            noexec       same as -n
            noglob       same as -f
            notify       same as -b
            nounset      same as -u
            onecmd       same as -t
            physical     same as -P
            posix        change the behavior of bash where the default
                         operation differs from the 1003.2 standard to
                         match the standard
            privileged   same as -p
            verbose      same as -v
#if defined (READLINE)
            vi           use a vi-style line editing interface
#endif /* READLINE */
            xtrace       same as -x
    -p  Turned on whenever the real and effective user ids do not match.
        Disables processing of the $ENV file and importing of shell
        functions.  Turning this option off causes the effective uid and
        gid to be set to the real uid and gid.
    -t  Exit after reading and executing one command.
    -u  Treat unset variables as an error when substituting.
    -v  Print shell input lines as they are read.
    -x  Print commands and their arguments as they are executed.
#if defined (BRACE_EXPANSION)
    -B  the shell will perform brace expansion
#endif /* BRACE_EXPANSION */
    -C  If set, disallow existing regular files to be overwritten
        by redirection of output.
#if defined (BANG_HISTORY)
    -H  Enable ! style history substitution.  This flag is on
        by default.
#endif /* BANG_HISTORY */
    -P  If set, do not follow symbolic links when executing commands
        such as cd which change the current directory.

Using + rather than - causes these flags to be turned off.  The
flags can also be used upon invocation of the shell.  The current
set of flags may be found in $-.  The remaining n ARGs are positional
parameters and are assigned, in order, to $1, $2, .. $n.  If no
ARGs are given, all shell variables are printed.
$END

static int set_ignoreeof ();
static int set_posix_mode ();

#if defined (READLINE)
static int set_edit_mode ();
static int get_edit_mode ();
#endif

#if defined (HISTORY)
static int bash_set_history ();
#endif

static char *on = "on";
static char *off = "off";

/* An a-list used to match long options for set -o to the corresponding
   option letter. */
struct {
  char *name;
  int letter;
} o_options[] = {
  { "allexport",  'a' },
#if defined (BRACE_EXPANSION)
  { "braceexpand",'B' },
#endif
  { "errexit",	  'e' },
  { "hashall",    'h' },
#if defined (BANG_HISTORY)
  { "histexpand", 'H' },
#endif /* BANG_HISTORY */
  { "keyword",    'k' },
  { "monitor",	  'm' },
  { "noclobber",  'C' },
  { "noexec",	  'n' },
  { "noglob",	  'f' },
#if defined (JOB_CONTROL)
  { "notify",	  'b' },
#endif /* JOB_CONTROL */
  { "nounset",	  'u' },
  { "onecmd",	  't' },
  { "physical",   'P' },
  { "privileged", 'p' },
  { "verbose",	  'v' },
  { "xtrace",	  'x' },
  {(char *)NULL, 0 },
};

struct {
  char *name;
  int *variable;
  Function *set_func;
  Function *get_func;
} binary_o_options[] = {
#if defined (HISTORY)
  { "history", &remember_on_history, bash_set_history, (Function *)NULL },
#endif
  { "ignoreeof", &ignoreeof, set_ignoreeof, (Function *)NULL },
  { "interactive-comments", &interactive_comments, (Function *)NULL, (Function *)NULL },
  { "posix", &posixly_correct, set_posix_mode, (Function *)NULL },
#if defined (READLINE)
  { "emacs", (int *)NULL, set_edit_mode, get_edit_mode },
  { "vi", (int *)NULL, set_edit_mode, get_edit_mode },
#endif
  { (char *)NULL, (int *)NULL }
};

#define GET_BINARY_O_OPTION_VALUE(i, name) \
  ((binary_o_options[i].get_func) ? (*binary_o_options[i].get_func) (name) \
				  : (*binary_o_options[i].variable))

#define SET_BINARY_O_OPTION_VALUE(i, onoff, name) \
  ((binary_o_options[i].set_func) ? (*binary_o_options[i].set_func) (onoff, name) \
				  : (*binary_o_options[i].variable = (onoff == FLAG_ON)))

int
minus_o_option_value (name)
     char *name;
{
  register int	i;
  int *on_or_off;

  for (i = 0; o_options[i].name; i++)
    {
      if (STREQ (name, o_options[i].name))
	{
	  on_or_off = find_flag (o_options[i].letter);
	  return ((on_or_off == FLAG_UNKNOWN) ? -1 : *on_or_off);
	}
    }
  for (i = 0; binary_o_options[i].name; i++)
    {
      if (STREQ (name, binary_o_options[i].name))
	return (GET_BINARY_O_OPTION_VALUE (i, name));
    }

  return (-1);
}

#define MINUS_O_FORMAT "%-15s\t%s\n"

static void
print_minus_o_option (name, value, pflag)
     char *name;
     int value, pflag;
{
  if (pflag == 0)
    printf (MINUS_O_FORMAT, name, value ? on : off);
  else
    printf ("set %co %s\n", value ? '-' : '+', name);
}

void
list_minus_o_opts (mode, reusable)
     int mode, reusable;
{
  register int	i;
  int *on_or_off, value;

  for (value = i = 0; o_options[i].name; i++)
    {
      on_or_off = find_flag (o_options[i].letter);
      if (on_or_off == FLAG_UNKNOWN)
	on_or_off = &value;
      if (mode == -1 || mode == *on_or_off)
	print_minus_o_option (o_options[i].name, *on_or_off, reusable);
    }
  for (i = 0; binary_o_options[i].name; i++)
    {
      value = GET_BINARY_O_OPTION_VALUE (i, binary_o_options[i].name);
      if (mode == -1 || mode == value)
	print_minus_o_option (binary_o_options[i].name, value, reusable);
    }
}

char **
get_minus_o_opts ()
{
  char **ret;
  int n, i, ind;

  n = (sizeof (o_options) / sizeof (o_options[0])) +
      (sizeof (binary_o_options) / sizeof (binary_o_options[0]));
  ret = alloc_array (n + 1);
  for (i = ind = 0; o_options[i].name; i++)
    ret[ind++] = o_options[i].name;
  for (i = 0; binary_o_options[i].name; i++)
    ret[ind++] = binary_o_options[i].name;
  ret[ind] = (char *)NULL;
  return ret;
}

static int
set_ignoreeof (on_or_off, option_name)
     int on_or_off;
     char *option_name;
{
  ignoreeof = on_or_off == FLAG_ON;
  unbind_variable ("ignoreeof");
  if (ignoreeof)
    bind_variable ("IGNOREEOF", "10"); 
  else
    unbind_variable ("IGNOREEOF");
  sv_ignoreeof ("IGNOREEOF");
  return 0;
}

static int
set_posix_mode (on_or_off, option_name)
     int on_or_off;
     char *option_name;
{
  posixly_correct = on_or_off == FLAG_ON;
  if (posixly_correct == 0)
    unbind_variable ("POSIXLY_CORRECT");
  else
    bind_variable ("POSIXLY_CORRECT", "y");
  sv_strict_posix ("POSIXLY_CORRECT");
  return (0);
}

#if defined (READLINE)
/* Magic.  This code `knows' how readline handles rl_editing_mode. */
static int
set_edit_mode (on_or_off, option_name)
     int on_or_off;
     char *option_name;
{
  int isemacs;

  if (on_or_off == FLAG_ON)
    {
      rl_variable_bind ("editing-mode", option_name);

      if (interactive)
	with_input_from_stdin ();
      no_line_editing = 0;
    }
  else
    {
      isemacs = rl_editing_mode == 1;
      if ((isemacs && *option_name == 'e') || (!isemacs && *option_name == 'v'))
	{
	  if (interactive)
	    with_input_from_stream (stdin, "stdin");
	  no_line_editing = 1;
	}
    }
  return 1-no_line_editing;
}

static int
get_edit_mode (name)
     char *name;
{
  return (*name == 'e' ? no_line_editing == 0 && rl_editing_mode == 1
		       : no_line_editing == 0 && rl_editing_mode == 0);
}
#endif /* READLINE */

#if defined (HISTORY)
static int
bash_set_history (on_or_off, option_name)
     int on_or_off;
     char *option_name;
{
  if (on_or_off == FLAG_ON)
    {
      bash_history_enable ();
      if (history_lines_this_session == 0)
	load_history ();
    }
  else
    bash_history_disable ();
  return (1 - remember_on_history);
}
#endif

int
set_minus_o_option (on_or_off, option_name)
     int on_or_off;
     char *option_name;
{
  int option_char;
  VFunction *set_func;
  register int i;

  for (i = 0; binary_o_options[i].name; i++)
    {
      if (STREQ (option_name, binary_o_options[i].name))
	{
	  SET_BINARY_O_OPTION_VALUE (i, on_or_off, option_name);
	  return (EXECUTION_SUCCESS);
	}
    }

  for (i = 0, option_char = -1, set_func = 0; o_options[i].name; i++)
    {
      if (STREQ (option_name, o_options[i].name))
	{
	  option_char = o_options[i].letter;
	  break;
	}
    }
  if (option_char == -1)
    {
      builtin_error ("%s: unknown option name", option_name);
      return (EXECUTION_FAILURE);
    }
 if (change_flag (option_char, on_or_off) == FLAG_ERROR)
    {
      bad_option (option_name);
      return (EXECUTION_FAILURE);
    }
  return (EXECUTION_SUCCESS);
}

static void
print_all_shell_variables ()
{
  SHELL_VAR **vars;

  vars = all_shell_variables ();
  if (vars)
    {
      print_var_list (vars);
      free (vars);
    }

  /* POSIX.2 does not allow function names and definitions to be output when
     `set' is invoked without options (PASC Interp #202). */
  if (posixly_correct == 0)
    {
      vars = all_shell_functions ();
      if (vars)
	{
	  print_func_list (vars);
	  free (vars);
	}
    }
}

void
set_shellopts ()
{
  char *value;
  int vsize, i, vptr, *ip, exported;
  SHELL_VAR *v;

  for (vsize = i = 0; o_options[i].name; i++)
    {
      ip = find_flag (o_options[i].letter);
      if (ip && *ip)
	vsize += strlen (o_options[i].name) + 1;
    }
  for (i = 0; binary_o_options[i].name; i++)
    if (GET_BINARY_O_OPTION_VALUE (i, binary_o_options[i].name))
      vsize += strlen (binary_o_options[i].name) + 1;

  value = xmalloc (vsize + 1);

  for (i = vptr = 0; o_options[i].name; i++)
    {
      ip = find_flag (o_options[i].letter);
      if (ip && *ip)
	{
	  strcpy (value + vptr, o_options[i].name);
	  vptr += strlen (o_options[i].name);
	  value[vptr++] = ':';
	}
    }
  for (i = 0; binary_o_options[i].name; i++)
    if (GET_BINARY_O_OPTION_VALUE (i, binary_o_options[i].name))
      {
	strcpy (value + vptr, binary_o_options[i].name);
	vptr += strlen (binary_o_options[i].name);
	value[vptr++] = ':';
      }
  if (vptr)
    vptr--;			/* cut off trailing colon */
  value[vptr] = '\0';

  v = find_variable ("SHELLOPTS");

  /* Turn off the read-only attribute so we can bind the new value, and
     note whether or not the variable was exported. */
  if (v)
    {
      VUNSETATTR (v, att_readonly);
      exported = exported_p (v);
    }
  else
    exported = 0;

  v = bind_variable ("SHELLOPTS", value);

  /* Turn the read-only attribute back on, and turn off the export attribute
     if it was set implicitly by mark_modified_vars and SHELLOPTS was not
     exported before we bound the new value. */
  VSETATTR (v, att_readonly);
  if (mark_modified_vars && exported == 0 && exported_p (v))
    VUNSETATTR (v, att_exported);

  free (value);
}

void
parse_shellopts (value)
     char *value;
{
  char *vname;
  int vptr;

  vptr = 0;
  while (vname = extract_colon_unit (value, &vptr))
    {
      set_minus_o_option (FLAG_ON, vname);
      free (vname);
    }
}

void
initialize_shell_options (no_shellopts)
     int no_shellopts;
{
  char *temp;
  SHELL_VAR *var;

  if (no_shellopts == 0)
    {
      var = find_variable ("SHELLOPTS");
      /* set up any shell options we may have inherited. */
      if (var && imported_p (var))
	{
	  temp = (array_p (var)) ? (char *)NULL : savestring (value_cell (var));
	  if (temp)
	    {
	      parse_shellopts (temp);
	      free (temp);
	    }
	}
    }

  /* Set up the $SHELLOPTS variable. */
  set_shellopts ();
}

/* Reset the values of the -o options that are not also shell flags.  This is
   called from execute_cmd.c:initialize_subshell() when setting up a subshell
   to run an executable shell script without a leading `#!'. */
void
reset_shell_options ()
{
#if defined (HISTORY)
  remember_on_history = 1;
#endif
  ignoreeof = 0;
}

/* Set some flags from the word values in the input list.  If LIST is empty,
   then print out the values of the variables instead.  If LIST contains
   non-flags, then set $1 - $9 to the successive words of LIST. */
int
set_builtin (list)
     WORD_LIST *list;
{
  int on_or_off, flag_name, force_assignment, opts_changed;
  WORD_LIST *l;
  register char *arg;

  if (list == 0)
    {
      print_all_shell_variables ();
      return (EXECUTION_SUCCESS);
    }

  /* Check validity of flag arguments. */
  if (*list->word->word == '-' || *list->word->word == '+')
    {
      for (l = list; l && (arg = l->word->word); l = l->next)
	{
	  char c;

	  if (arg[0] != '-' && arg[0] != '+')
	    break;

	  /* `-' or `--' signifies end of flag arguments. */
	  if (arg[0] == '-' && (!arg[1] || (arg[1] == '-' && !arg[2])))
	    break;

	  while (c = *++arg)
	    {
	      if (find_flag (c) == FLAG_UNKNOWN && c != 'o')
		{
		  char s[2];
		  s[0] = c; s[1] = '\0';
		  bad_option (s);
		  if (c == '?')
		    builtin_usage ();
		  return (c == '?' ? EXECUTION_SUCCESS : EXECUTION_FAILURE);
		}
	    }
	}
    }

  /* Do the set command.  While the list consists of words starting with
     '-' or '+' treat them as flags, otherwise, start assigning them to
     $1 ... $n. */
  for (force_assignment = opts_changed = 0; list; )
    {
      arg = list->word->word;

      /* If the argument is `--' or `-' then signal the end of the list
	 and remember the remaining arguments. */
      if (arg[0] == '-' && (!arg[1] || (arg[1] == '-' && !arg[2])))
	{
	  list = list->next;

	  /* `set --' unsets the positional parameters. */
	  if (arg[1] == '-')
	    force_assignment = 1;

	  /* Until told differently, the old shell behaviour of
	     `set - [arg ...]' being equivalent to `set +xv [arg ...]'
	     stands.  Posix.2 says the behaviour is marked as obsolescent. */
	  else
	    {
	      change_flag ('x', '+');
	      change_flag ('v', '+');
	      opts_changed = 1;
	    }

	  break;
	}

      if ((on_or_off = *arg) && (on_or_off == '-' || on_or_off == '+'))
	{
	  while (flag_name = *++arg)
	    {
	      if (flag_name == '?')
		{
		  builtin_usage ();
		  return (EXECUTION_SUCCESS);
		}
	      else if (flag_name == 'o') /* -+o option-name */
		{
		  char *option_name;
		  WORD_LIST *opt;

		  opt = list->next;

		  if (opt == 0)
		    {
		      list_minus_o_opts (-1, (on_or_off == '+'));
		      continue;
		    }

		  option_name = opt->word->word;

		  if (option_name == 0 || *option_name == '\0' ||
		      *option_name == '-' || *option_name == '+')
		    {
		      list_minus_o_opts (-1, (on_or_off == '+'));
		      continue;
		    }
		  list = list->next; /* Skip over option name. */

		  opts_changed = 1;
		  if (set_minus_o_option (on_or_off, option_name) != EXECUTION_SUCCESS)
		    {
		      set_shellopts ();
		      return (EXECUTION_FAILURE);
		    }
		}
	      else if (change_flag (flag_name, on_or_off) == FLAG_ERROR)
		{
		  char opt[3];
		  opt[0] = on_or_off;
		  opt[1] = flag_name;
		  opt[2] = '\0';
		  bad_option (opt);
		  builtin_usage ();
		  set_shellopts ();
		  return (EXECUTION_FAILURE);
		}
	      opts_changed = 1;
	    }
	}
      else
	{
	  break;
	}
      list = list->next;
    }

  /* Assigning $1 ... $n */
  if (list || force_assignment)
    remember_args (list, 1);
  /* Set up new value of $SHELLOPTS */
  if (opts_changed)
    set_shellopts ();
  return (EXECUTION_SUCCESS);
}

$BUILTIN unset
$FUNCTION unset_builtin
$SHORT_DOC unset [-f] [-v] [name ...]
For each NAME, remove the corresponding variable or function.  Given
the `-v', unset will only act on variables.  Given the `-f' flag,
unset will only act on functions.  With neither flag, unset first
tries to unset a variable, and if that fails, then tries to unset a
function.  Some variables cannot be unset; also see readonly.
$END

#define NEXT_VARIABLE()	any_failed++; list = list->next; continue;

int
unset_builtin (list)
  WORD_LIST *list;
{
  int unset_function, unset_variable, unset_array, opt, any_failed;
  char *name;

  unset_function = unset_variable = unset_array = any_failed = 0;

  reset_internal_getopt ();
  while ((opt = internal_getopt (list, "fv")) != -1)
    {
      switch (opt)
	{
	case 'f':
	  unset_function = 1;
	  break;
	case 'v':
	  unset_variable = 1;
	  break;
	default:
	  builtin_usage ();
	  return (EX_USAGE);
	}
    }

  list = loptend;

  if (unset_function && unset_variable)
    {
      builtin_error ("cannot simultaneously unset a function and a variable");
      return (EXECUTION_FAILURE);
    }

  while (list)
    {
      SHELL_VAR *var;
      int tem;
#if defined (ARRAY_VARS)
      char *t;
#endif

      name = list->word->word;

#if defined (ARRAY_VARS)
      if (!unset_function && valid_array_reference (name))
	{
	  t = strchr (name, '[');
	  *t++ = '\0';
	  unset_array++;
	}
#endif

      /* Bash allows functions with names which are not valid identifiers
	 to be created when not in posix mode, so check only when in posix
	 mode when unsetting a function. */
      if (((unset_function && posixly_correct) || !unset_function) && legal_identifier (name) == 0)
	{
	  builtin_error ("`%s': not a valid identifier", name);
	  NEXT_VARIABLE ();
	}

      var = unset_function ? find_function (name) : find_variable (name);

      if (var && !unset_function && non_unsettable_p (var))
	{
	  builtin_error ("%s: cannot unset", name);
	  NEXT_VARIABLE ();
	}

      /* Posix.2 says that unsetting readonly variables is an error. */
      if (var && readonly_p (var))
	{
	  builtin_error ("%s: cannot unset: readonly %s",
			 name, unset_function ? "function" : "variable");
	  NEXT_VARIABLE ();
	}

      /* Unless the -f option is supplied, the name refers to a variable. */
#if defined (ARRAY_VARS)
      if (var && unset_array)
	{
	  if (array_p (var) == 0)
	    {
	      builtin_error ("%s: not an array variable", name);
	      NEXT_VARIABLE ();
	    }
	  else
	    tem = unbind_array_element (var, t);
	}
      else
#endif /* ARRAY_VARS */
      tem = makunbound (name, unset_function ? shell_functions : shell_variables);

      /* This is what Posix.2 draft 11+ says.  ``If neither -f nor -v
	 is specified, the name refers to a variable; if a variable by
	 that name does not exist, a function by that name, if any,
	 shall be unset.'' */
      if (tem == -1 && !unset_function && !unset_variable)
	tem = makunbound (name, shell_functions);

      if (tem == -1)
	any_failed++;
      else if (!unset_function)
	stupidly_hack_special_variables (name);

      list = list->next;
    }

  return (any_failed ? EXECUTION_FAILURE : EXECUTION_SUCCESS);
}