trunk/libltdl/lt_dlloader.c

/* lt_dlloader.c -- dynamic library loader interface

   Copyright (C) 2004, 2007, 2008 Free Software Foundation, Inc.
   Written by Gary V. Vaughan, 2004

   NOTE: The canonical source of this file is maintained with the
   GNU Libtool package.  Report bugs to bug-libtool@gnu.org.

GNU Libltdl is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

As a special exception to the GNU Lesser General Public License,
if you distribute this file as part of a program or library that
is built using GNU Libtool, you may include this file under the
same distribution terms that you use for the rest of that program.

GNU Libltdl 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with GNU Libltdl; see the file COPYING.LIB.  If not, a
copy can be downloaded from  http://www.gnu.org/licenses/lgpl.html,
or obtained by writing to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

#include "lt__private.h"
#include "lt_dlloader.h"

#define RETURN_SUCCESS 0
#define RETURN_FAILURE 1

static void *   loader_callback (SList *item, void *userdata);

/* A list of all the dlloaders we know about, each stored as a boxed
   SList item:  */
static  SList    *loaders               = 0;


/* Return NULL, unless the loader in this ITEM has a matching name,
   in which case we return the matching item so that its address is
   passed back out (for possible freeing) by slist_remove.  */
static void *
loader_callback (SList *item, void *userdata)
{
  const lt_dlvtable *vtable = (const lt_dlvtable *) item->userdata;
  const char *      name    = (const char *) userdata;

  assert (vtable);

  return streq (vtable->name, name) ? (void *) item : NULL;
}


/* Hook VTABLE into our global LOADERS list according to its own
   PRIORITY field value.  */
int
lt_dlloader_add (const lt_dlvtable *vtable)
{
  SList *item;

  if ((vtable == 0)     /* diagnose invalid vtable fields */
      || (vtable->module_open == 0)
      || (vtable->module_close == 0)
      || (vtable->find_sym == 0)
      || ((vtable->priority != LT_DLLOADER_PREPEND) &&
          (vtable->priority != LT_DLLOADER_APPEND)))
    {
      LT__SETERROR (INVALID_LOADER);
      return RETURN_FAILURE;
    }

  item = slist_box (vtable);
  if (!item)
    {
      (*lt__alloc_die) ();

      /* Let the caller know something went wrong if lt__alloc_die
         doesn't abort.  */
      return RETURN_FAILURE;
    }

  if (vtable->priority == LT_DLLOADER_PREPEND)
    {
      loaders = slist_cons (item, loaders);
    }
  else
    {
      assert (vtable->priority == LT_DLLOADER_APPEND);
      loaders = slist_concat (loaders, item);
    }

  return RETURN_SUCCESS;
}

#ifdef LT_DEBUG_LOADERS
static void *
loader_dump_callback (SList *item, void *userdata)
{
  const lt_dlvtable *vtable = (const lt_dlvtable *) item->userdata;
  fprintf (stderr, ", %s", (vtable && vtable->name) ? vtable->name : "(null)");
  return 0;
}

void
lt_dlloader_dump (void)
{
  fprintf (stderr, "loaders: ");
  if (!loaders)
    {
      fprintf (stderr, "(empty)");
    }
  else
    {
      const lt_dlvtable *head = (const lt_dlvtable *) loaders->userdata;
      fprintf (stderr, "%s", (head && head->name) ? head->name : "(null)");
      if (slist_tail (loaders))
        slist_foreach (slist_tail (loaders), loader_dump_callback, NULL);
    }
  fprintf (stderr, "\n");
}
#endif

/* An iterator for the global loader list: if LOADER is NULL, then
   return the first element, otherwise the following element.  */
lt_dlloader
lt_dlloader_next (lt_dlloader loader)
{
  SList *item = (SList *) loader;
  return (lt_dlloader) (item ? item->next : loaders);
}


/* Non-destructive unboxing of a loader.  */
const lt_dlvtable *
lt_dlloader_get (lt_dlloader loader)
{
  return (const lt_dlvtable *) (loader ? ((SList *) loader)->userdata : NULL);
}


/* Return the contents of the first item in the global loader list
   with a matching NAME after removing it from that list.  If there
   was no match, return NULL; if there is an error, return NULL and
   set an error for lt_dlerror; do not set an error if only resident
   modules need this loader; in either case, the loader list is not
   changed if NULL is returned.  */
lt_dlvtable *
lt_dlloader_remove (char *name)
{
  const lt_dlvtable *   vtable  = lt_dlloader_find (name);
  static const char     id_string[] = "lt_dlloader_remove";
  lt_dlinterface_id     iface;
  lt_dlhandle           handle = 0;
  int                   in_use = 0;
  int                   in_use_by_resident = 0;

  if (!vtable)
    {
      LT__SETERROR (INVALID_LOADER);
      return 0;
    }

  /* Fail if there are any open modules which use this loader.  */
  iface = lt_dlinterface_register (id_string, NULL);
  while ((handle = lt_dlhandle_iterate (iface, handle)))
    {
      lt_dlhandle cur = handle;
      if (cur->vtable == vtable)
        {
          in_use = 1;
          if (lt_dlisresident (handle))
            in_use_by_resident = 1;
        }
    }
  lt_dlinterface_free (iface);
  if (in_use)
    {
      if (!in_use_by_resident)
        LT__SETERROR (REMOVE_LOADER);
      return 0;
    }

  /* Call the loader finalisation function.  */
  if (vtable && vtable->dlloader_exit)
    {
      if ((*vtable->dlloader_exit) (vtable->dlloader_data) != 0)
        {
          /* If there is an exit function, and it returns non-zero
             then it must set an error, and we will not remove it
             from the list.  */
          return 0;
        }
    }

  /* If we got this far, remove the loader from our global list.  */
  return (lt_dlvtable *)
      slist_unbox ((SList *) slist_remove (&loaders, loader_callback, name));
}


const lt_dlvtable *
lt_dlloader_find (char *name)
{
  return lt_dlloader_get (slist_find (loaders, loader_callback, name));
}
Revision:	1028
Committed:	Sun Nov 8 13:03:38 2009 UTC (15 years, 9 months ago) by michael
Content type:	text/x-csrc
Original Path:	*ircd-hybrid/libltdl/lt_dlloader.c*
File size:	6046 byte(s)
Log Message:	- move ircd-hybrid-7.2 to trunk
#	User	Rev	Content
1	michael	945	/* lt_dlloader.c -- dynamic library loader interface
2
3			Copyright (C) 2004, 2007, 2008 Free Software Foundation, Inc.
4			Written by Gary V. Vaughan, 2004
5
6			NOTE: The canonical source of this file is maintained with the
7			GNU Libtool package. Report bugs to bug-libtool@gnu.org.
8
9			GNU Libltdl is free software; you can redistribute it and/or
10			modify it under the terms of the GNU Lesser General Public
11			License as published by the Free Software Foundation; either
12			version 2 of the License, or (at your option) any later version.
13
14			As a special exception to the GNU Lesser General Public License,
15			if you distribute this file as part of a program or library that
16			is built using GNU Libtool, you may include this file under the
17			same distribution terms that you use for the rest of that program.
18
19			GNU Libltdl is distributed in the hope that it will be useful,
20			but WITHOUT ANY WARRANTY; without even the implied warranty of
21			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22			GNU Lesser General Public License for more details.
23
24			You should have received a copy of the GNU Lesser General Public
25			License along with GNU Libltdl; see the file COPYING.LIB. If not, a
26			copy can be downloaded from http://www.gnu.org/licenses/lgpl.html,
27			or obtained by writing to the Free Software Foundation, Inc.,
28			51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
29			*/
30
31			#include "lt__private.h"
32			#include "lt_dlloader.h"
33
34			#define RETURN_SUCCESS 0
35			#define RETURN_FAILURE 1
36
37			static void * loader_callback (SList item, void userdata);
38
39			/* A list of all the dlloaders we know about, each stored as a boxed
40			SList item: */
41			static SList *loaders = 0;
42
43
44			/* Return NULL, unless the loader in this ITEM has a matching name,
45			in which case we return the matching item so that its address is
46			passed back out (for possible freeing) by slist_remove. */
47			static void *
48			loader_callback (SList item, void userdata)
49			{
50			const lt_dlvtable vtable = (const lt_dlvtable ) item->userdata;
51			const char * name = (const char *) userdata;
52
53			assert (vtable);
54
55			return streq (vtable->name, name) ? (void *) item : NULL;
56			}
57
58
59			/* Hook VTABLE into our global LOADERS list according to its own
60			PRIORITY field value. */
61			int
62			lt_dlloader_add (const lt_dlvtable *vtable)
63			{
64			SList *item;
65
66			if ((vtable == 0) /* diagnose invalid vtable fields */
67			\|\| (vtable->module_open == 0)
68			\|\| (vtable->module_close == 0)
69			\|\| (vtable->find_sym == 0)
70			\|\| ((vtable->priority != LT_DLLOADER_PREPEND) &&
71			(vtable->priority != LT_DLLOADER_APPEND)))
72			{
73			LT__SETERROR (INVALID_LOADER);
74			return RETURN_FAILURE;
75			}
76
77			item = slist_box (vtable);
78			if (!item)
79			{
80			(*lt__alloc_die) ();
81
82			/* Let the caller know something went wrong if lt__alloc_die
83			doesn't abort. */
84			return RETURN_FAILURE;
85			}
86
87			if (vtable->priority == LT_DLLOADER_PREPEND)
88			{
89			loaders = slist_cons (item, loaders);
90			}
91			else
92			{
93			assert (vtable->priority == LT_DLLOADER_APPEND);
94			loaders = slist_concat (loaders, item);
95			}
96
97			return RETURN_SUCCESS;
98			}
99
100			#ifdef LT_DEBUG_LOADERS
101			static void *
102			loader_dump_callback (SList item, void userdata)
103			{
104			const lt_dlvtable vtable = (const lt_dlvtable ) item->userdata;
105			fprintf (stderr, ", %s", (vtable && vtable->name) ? vtable->name : "(null)");
106			return 0;
107			}
108
109			void
110			lt_dlloader_dump (void)
111			{
112			fprintf (stderr, "loaders: ");
113			if (!loaders)
114			{
115			fprintf (stderr, "(empty)");
116			}
117			else
118			{
119			const lt_dlvtable head = (const lt_dlvtable ) loaders->userdata;
120			fprintf (stderr, "%s", (head && head->name) ? head->name : "(null)");
121			if (slist_tail (loaders))
122			slist_foreach (slist_tail (loaders), loader_dump_callback, NULL);
123			}
124			fprintf (stderr, "\n");
125			}
126			#endif
127
128			/* An iterator for the global loader list: if LOADER is NULL, then
129			return the first element, otherwise the following element. */
130			lt_dlloader
131			lt_dlloader_next (lt_dlloader loader)
132			{
133			SList item = (SList ) loader;
134			return (lt_dlloader) (item ? item->next : loaders);
135			}
136
137
138			/* Non-destructive unboxing of a loader. */
139			const lt_dlvtable *
140			lt_dlloader_get (lt_dlloader loader)
141			{
142			return (const lt_dlvtable ) (loader ? ((SList ) loader)->userdata : NULL);
143			}
144
145
146			/* Return the contents of the first item in the global loader list
147			with a matching NAME after removing it from that list. If there
148			was no match, return NULL; if there is an error, return NULL and
149			set an error for lt_dlerror; do not set an error if only resident
150			modules need this loader; in either case, the loader list is not
151			changed if NULL is returned. */
152			lt_dlvtable *
153			lt_dlloader_remove (char *name)
154			{
155			const lt_dlvtable * vtable = lt_dlloader_find (name);
156			static const char id_string[] = "lt_dlloader_remove";
157			lt_dlinterface_id iface;
158			lt_dlhandle handle = 0;
159			int in_use = 0;
160			int in_use_by_resident = 0;
161
162			if (!vtable)
163			{
164			LT__SETERROR (INVALID_LOADER);
165			return 0;
166			}
167
168			/* Fail if there are any open modules which use this loader. */
169			iface = lt_dlinterface_register (id_string, NULL);
170			while ((handle = lt_dlhandle_iterate (iface, handle)))
171			{
172			lt_dlhandle cur = handle;
173			if (cur->vtable == vtable)
174			{
175			in_use = 1;
176			if (lt_dlisresident (handle))
177			in_use_by_resident = 1;
178			}
179			}
180			lt_dlinterface_free (iface);
181			if (in_use)
182			{
183			if (!in_use_by_resident)
184			LT__SETERROR (REMOVE_LOADER);
185			return 0;
186			}
187
188			/* Call the loader finalisation function. */
189			if (vtable && vtable->dlloader_exit)
190			{
191			if ((*vtable->dlloader_exit) (vtable->dlloader_data) != 0)
192			{
193			/* If there is an exit function, and it returns non-zero
194			then it must set an error, and we will not remove it
195			from the list. */
196			return 0;
197			}
198			}
199
200			/* If we got this far, remove the loader from our global list. */
201			return (lt_dlvtable *)
202			slist_unbox ((SList *) slist_remove (&loaders, loader_callback, name));
203			}
204
205
206			const lt_dlvtable *
207			lt_dlloader_find (char *name)
208			{
209			return lt_dlloader_get (slist_find (loaders, loader_callback, name));
210			}