source: trunk/essentials/app-shells/bash/builtins/setattr.def

This file is setattr.def, from which is created setattr.c.
It implements the builtins "export" and "readonly", in Bash.

Copyright (C) 1987-2004 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 setattr.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 "../bashintl.h"

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

extern int posixly_correct;
extern int array_needs_making;
extern char *this_command_name;
extern sh_builtin_func_t *this_shell_builtin;

#ifdef ARRAY_VARS
extern int declare_builtin __P((WORD_LIST *));
#endif

#define READONLY_OR_EXPORT \
  (this_shell_builtin == readonly_builtin || this_shell_builtin == export_builtin)

$BUILTIN export
$FUNCTION export_builtin
$SHORT_DOC export [-nf] [name[=value] ...] or export -p
NAMEs are marked for automatic export to the environment of
subsequently executed commands.  If the -f option is given,
the NAMEs refer to functions.  If no NAMEs are given, or if `-p'
is given, a list of all names that are exported in this shell is
printed.  An argument of `-n' says to remove the export property
from subsequent NAMEs.  An argument of `--' disables further option
processing.
$END

/* For each variable name in LIST, make that variable appear in the
   environment passed to simple commands.  If there is no LIST, then
   print all such variables.  An argument of `-n' says to remove the
   exported attribute from variables named in LIST.  An argument of
  -f indicates that the names present in LIST refer to functions. */
int
export_builtin (list)
     register WORD_LIST *list;
{
  return (set_or_show_attributes (list, att_exported, 0));
}

$BUILTIN readonly
$FUNCTION readonly_builtin
$SHORT_DOC readonly [-af] [name[=value] ...] or readonly -p
The given NAMEs are marked readonly and the values of these NAMEs may
not be changed by subsequent assignment.  If the -f option is given,
then functions corresponding to the NAMEs are so marked.  If no
arguments are given, or if `-p' is given, a list of all readonly names
is printed.  The `-a' option means to treat each NAME as
an array variable.  An argument of `--' disables further option
processing.
$END

/* For each variable name in LIST, make that variable readonly.  Given an
   empty LIST, print out all existing readonly variables. */
int
readonly_builtin (list)
     register WORD_LIST *list;
{
  return (set_or_show_attributes (list, att_readonly, 0));
}

#if defined (ARRAY_VARS)
#  define ATTROPTS      "afnp"
#else
#  define ATTROPTS      "fnp"
#endif

/* For each variable name in LIST, make that variable have the specified
   ATTRIBUTE.  An arg of `-n' says to remove the attribute from the the
   remaining names in LIST (doesn't work for readonly). */
int
set_or_show_attributes (list, attribute, nodefs)
     register WORD_LIST *list;
     int attribute, nodefs;
{
  register SHELL_VAR *var;
  int assign, undo, functions_only, arrays_only, any_failed, assign_error, opt;
  int aflags;
  char *name;
#if defined (ARRAY_VARS)
  WORD_LIST *nlist, *tlist;
  WORD_DESC *w;
#endif

  undo = functions_only = arrays_only = any_failed = assign_error = 0;
  /* Read arguments from the front of the list. */
  reset_internal_getopt ();
  while ((opt = internal_getopt (list, ATTROPTS)) != -1)
    {
      switch (opt)
        {
          case 'n':
            undo = 1;
            break;
          case 'f':
            functions_only = 1;
            break;
#if defined (ARRAY_VARS)
          case 'a':
             arrays_only = 1;
             break;
#endif
          case 'p':
            break;
          default:
            builtin_usage ();
            return (EX_USAGE);
        }
    }
  list = loptend;

  if (list)
    {
      if (attribute & att_exported)
        array_needs_making = 1;

      /* Cannot undo readonly status, silently disallowed. */
      if (undo && (attribute & att_readonly))
        attribute &= ~att_readonly;

      while (list)
        {
          name = list->word->word;

          if (functions_only)           /* xxx -f name */
            {
              var = find_function (name);
              if (var == 0)
                {
                  builtin_error (_("%s: not a function"), name);
                  any_failed++;
                }
              else
                SETVARATTR (var, attribute, undo);

              list = list->next;
              continue;
            }

          /* xxx [-np] name[=value] */
          assign = assignment (name, 0);

          aflags = 0;
          if (assign)
            {
              name[assign] = '\0';
              if (name[assign - 1] == '+')
                {
                  aflags |= ASS_APPEND;
                  name[assign - 1] = '\0';
                }
            }

          if (legal_identifier (name) == 0)
            {
              sh_invalidid (name);
              if (assign)
                assign_error++;
              else
                any_failed++;
              list = list->next;
              continue;
            }

          if (assign)   /* xxx [-np] name=value */
            {
              name[assign] = '=';
              if (aflags & ASS_APPEND)
                name[assign - 1] = '+';
#if defined (ARRAY_VARS)
              /* Let's try something here.  Turn readonly -a xxx=yyy into
                 declare -ra xxx=yyy and see what that gets us. */
              if (arrays_only)
                {
                  tlist = list->next;
                  list->next = (WORD_LIST *)NULL;
                  w = make_word ("-ra");
                  nlist = make_word_list (w, list);
                  opt = declare_builtin (nlist);
                  if (opt != EXECUTION_SUCCESS)
                    assign_error++;
                  list->next = tlist;
                  dispose_word (w);
                  free (nlist);
                }
              else
#endif
              /* This word has already been expanded once with command
                 and parameter expansion.  Call do_assignment_no_expand (),
                 which does not do command or parameter substitution.  If
                 the assignment is not performed correctly, flag an error. */
              if (do_assignment_no_expand (name) == 0)
                assign_error++;
              name[assign] = '\0';
              if (aflags & ASS_APPEND)
                name[assign - 1] = '\0';
            }

          set_var_attribute (name, attribute, undo);
          list = list->next;
        }
    }
  else
    {
      SHELL_VAR **variable_list;
      register int i;

      if ((attribute & att_function) || functions_only)
        {
          variable_list = all_shell_functions ();
          if (attribute != att_function)
            attribute &= ~att_function; /* so declare -xf works, for example */
        }
      else
        variable_list = all_shell_variables ();

#if defined (ARRAY_VARS)
      if (attribute & att_array)
        {
          arrays_only++;
          if (attribute != att_array)
            attribute &= ~att_array;
        }
#endif

      if (variable_list)
        {
          for (i = 0; var = variable_list[i]; i++)
            {
#if defined (ARRAY_VARS)
              if (arrays_only && array_p (var) == 0)
                continue;
#endif
              if ((var->attributes & attribute))
                show_var_attributes (var, READONLY_OR_EXPORT, nodefs);
            }
          free (variable_list);
        }
    }

  return (assign_error ? EX_BADASSIGN
                       : ((any_failed == 0) ? EXECUTION_SUCCESS
                                            : EXECUTION_FAILURE));
}

/* Show the attributes for shell variable VAR.  If NODEFS is non-zero,
   don't show function definitions along with the name.  If PATTR is
   non-zero, it indicates we're being called from `export' or `readonly'.
   In POSIX mode, this prints the name of the calling builtin (`export'
   or `readonly') instead of `declare', and doesn't print function defs
   when called by `export' or `readonly'. */
int
show_var_attributes (var, pattr, nodefs)
     SHELL_VAR *var;
     int pattr, nodefs;
{
  char flags[8], *x;
  int i;

  i = 0;

  /* pattr == 0 means we are called from `declare'. */
  if (pattr == 0 || posixly_correct == 0)
    {
#if defined (ARRAY_VARS)
      if (array_p (var))
        flags[i++] = 'a';
#endif

      if (function_p (var))
        flags[i++] = 'f';

      if (integer_p (var))
        flags[i++] = 'i';

      if (readonly_p (var))
        flags[i++] = 'r';

      if (trace_p (var))
        flags[i++] = 't';

      if (exported_p (var))
        flags[i++] = 'x';
    }
  else
    {
#if defined (ARRAY_VARS)
      if (array_p (var))
        flags[i++] = 'a';
#endif

      if (function_p (var))
        flags[i++] = 'f';
    }

  flags[i] = '\0';

  /* If we're printing functions with definitions, print the function def
     first, then the attributes, instead of printing output that can't be
     reused as input to recreate the current state. */
  if (function_p (var) && nodefs == 0 && (pattr == 0 || posixly_correct == 0))
    {
      printf ("%s\n", named_function_string (var->name, function_cell (var), 1));
      nodefs++;
      if (pattr == 0 && i == 1 && flags[0] == 'f')
        return 0;               /* don't print `declare -f name' */
    }

  if (pattr == 0 || posixly_correct == 0)
    printf ("declare -%s ", i ? flags : "-");
  else if (i)
    printf ("%s -%s ", this_command_name, flags);
  else
    printf ("%s ", this_command_name);

#if defined (ARRAY_VARS)
 if (array_p (var))
    print_array_assignment (var, 1);
  else
#endif
  /* force `readonly' and `export' to not print out function definitions
     when in POSIX mode. */
  if (nodefs || (function_p (var) && pattr != 0 && posixly_correct))
    printf ("%s\n", var->name);
  else if (function_p (var))
    printf ("%s\n", named_function_string (var->name, function_cell (var), 1));
  else if (invisible_p (var))
    printf ("%s\n", var->name);
  else
    {
      x = sh_double_quote (var_isset (var) ? value_cell (var) : "");
      printf ("%s=%s\n", var->name, x);
      free (x);
    }
  return (0);
}

int
show_name_attributes (name, nodefs)
     char *name;
     int nodefs;
{
  SHELL_VAR *var;

  var = find_variable_internal (name, 1);

  if (var && invisible_p (var) == 0)
    {
      show_var_attributes (var, READONLY_OR_EXPORT, nodefs);
      return (0);
    }
  else
    return (1);
}

void
set_var_attribute (name, attribute, undo)
     char *name;
     int attribute, undo;
{
  SHELL_VAR *var, *tv;
  char *tvalue;

  if (undo)
    var = find_variable (name);
  else
    {
      tv = find_tempenv_variable (name);
      /* XXX -- need to handle case where tv is a temp variable in a
         function-scope context, since function_env has been merged into
         the local variables table. */
      if (tv && tempvar_p (tv))
        {
          tvalue = var_isset (tv) ? savestring (value_cell (tv)) : savestring ("");

          var = bind_variable (tv->name, tvalue, 0);
          var->attributes |= tv->attributes & ~att_tempvar;
          VSETATTR (tv, att_propagate);
          if (var->context != 0)
            VSETATTR (var, att_propagate);
          SETVARATTR (tv, attribute, undo);     /* XXX */

          stupidly_hack_special_variables (tv->name);

          free (tvalue);
        }
      else
        {
          var = find_variable_internal (name, 0);
          if (var == 0)
            {
              var = bind_variable (name, (char *)NULL, 0);
              VSETATTR (var, att_invisible);
            }
          else if (var->context != 0)
            VSETATTR (var, att_propagate);
        }
    }

  if (var)
    SETVARATTR (var, attribute, undo);

  if (var && (exported_p (var) || (attribute & att_exported)))
    array_needs_making++;       /* XXX */
}