8.1.0beta4/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 (const 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, (void *) name));
}


const lt_dlvtable *
lt_dlloader_find (const char *name)
{
  return lt_dlloader_get (slist_find (loaders, loader_callback, (void *) name));
}
Revision:	1988
Committed:	Thu May 9 14:27:04 2013 UTC (13 years, 2 months ago) by michael
Content type:	text/x-csrc
File size:	6076 byte(s)
Log Message:	RELEASE TAG 8.1.0beta4
#	Content
1	/* 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 (const 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, (void ) name));
203	}
204
205
206	const lt_dlvtable *
207	lt_dlloader_find (const char *name)
208	{
209	return lt_dlloader_get (slist_find (loaders, loader_callback, (void *) name));
210	}