modules/load.c

   1 /* GNU m4 -- A simple macro processor
   2    Copyright (C) 2000, 2005-2008, 2010, 2013 Free Software Foundation,
   3    Inc.
   4
   5    This file is part of GNU M4.
   6
   7    GNU M4 is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    GNU M4 is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include <config.h>
  22
  23 /* This module needs private symbols, and may not compile correctly if
  24    m4private.h isn't included.  */
  25 #include "m4private.h"
  26
  27
  28 /* Rename exported symbols for dlpreload()ing.  */
  29 #define m4_builtin_table        load_LTX_m4_builtin_table
  30 #define m4_macro_table          load_LTX_m4_macro_table
  31
  32
  33 /* Maintain each of the builtins implemented in this modules along
  34    with their details in a single table for easy maintenance.
  35
  36            function     macros  blind   side    minargs maxargs */
  37 #define builtin_functions                                       \
  38   BUILTIN (m4modules,   false,  false,  false,  0,      0  )    \
  39   BUILTIN (refcount,    false,  true,   false,  1,      1  )    \
  40   BUILTIN (unload,      false,  true,   false,  1,      1  )    \
  41
  42
  43 /* Generate prototypes for each builtin handler function. */
  44 #define BUILTIN(handler, macros,  blind, side, min, max) M4BUILTIN (handler)
  45   builtin_functions
  46 #undef BUILTIN
  47
  48
  49 /* Generate a table for mapping m4 symbol names to handler functions. */
  50 const m4_builtin m4_builtin_table[] =
  51 {
  52 #define BUILTIN(handler, macros, blind, side, min, max)                 \
  53   M4BUILTIN_ENTRY (handler, #handler, macros, blind, side, min, max)
  54
  55   builtin_functions
  56 #undef BUILTIN
  57
  58   { NULL, NULL, 0, 0, 0 },
  59 };
  60
  61
  62 /* A table for mapping m4 symbol names to simple expansion text. */
  63 const m4_macro m4_macro_table[] =
  64 {
  65   /* name               text    min     max */
  66   { "__load__",         "",     0,      0 },
  67   { NULL,               NULL,   0,      0 },
  68 };
  69
  70 \f
  71 /* This module cannot be safely unloaded from memory, incase the unload
  72    is triggered by the unload builtin, and the module is removed while
  73    unload is in progress.  */
  74 M4INIT_HANDLER (load)
  75 {
  76   const char *err = m4_module_makeresident (module);
  77   if (err)
  78     m4_error (context, 0, 0, NULL, _("cannot make module `%s' resident: %s"),
  79               m4_get_module_name (module), err);
  80 }
  81
  82
  83 \f
  84 /* Loading an external module at runtime.
  85    The following functions provide the implementation for each
  86    of the m4 builtins declared in `m4_builtin_table[]' above.  */
  87
  88 /**
  89  * m4modules()
  90  **/
  91 M4BUILTIN_HANDLER (m4modules)
  92 {
  93   /* The expansion of this builtin is a comma separated list of
  94      loaded modules.  */
  95   m4_module *module = m4__module_next (NULL);
  96
  97   if (module)
  98     do
  99       {
 100         m4_shipout_string (context, obs, m4_get_module_name (module), SIZE_MAX,
 101                            true);
 102
 103         if ((module = m4__module_next (module)))
 104           obstack_1grow (obs, ',');
 105       }
 106     while (module);
 107 }
 108
 109 /**
 110  * refcount(module)
 111  **/
 112 M4BUILTIN_HANDLER (refcount)
 113 {
 114   m4_module *module = m4__module_find (M4ARG (1));
 115   m4_shipout_int (obs, module ? m4_module_refcount (module) : 0);
 116 }
 117
 118 /**
 119  * unload(MODULE-NAME)
 120  **/
 121 M4BUILTIN_HANDLER (unload)
 122 {
 123   /* Remove all builtins and macros installed by the named module,
 124      and then unload the module from memory entirely.  */
 125   m4_module_unload (context, M4ARG(1), obs);
 126 }