Update.
[glibc.git] / elf / dl-close.c
blobe1ca142a690084280bdba5f108a732914a64ca5e
1 /* Close a shared object opened by `_dl_open'.
2 Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
20 #include <dlfcn.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <bits/libc-lock.h>
24 #include <elf/ldsodefs.h>
25 #include <sys/types.h>
26 #include <sys/mman.h>
29 /* During the program run we must not modify the global data of
30 loaded shared object simultanously in two threads. Therefore we
31 protect `dlopen' and `dlclose' in dlclose.c. */
32 __libc_lock_define (extern, _dl_load_lock)
34 #define LOSE(s) _dl_signal_error (0, map->l_name, s)
36 void
37 internal_function
38 _dl_close (struct link_map *map)
40 struct link_map **list;
41 unsigned int i;
43 if (map->l_opencount == 0)
44 LOSE ("shared object not open");
46 /* Acquire the lock. */
47 __libc_lock_lock (_dl_load_lock);
49 /* Decrement the reference count. */
50 if (map->l_opencount > 1 || map->l_type != lt_loaded)
52 /* There are still references to this object. Do nothing more. */
53 --map->l_opencount;
54 __libc_lock_unlock (_dl_load_lock);
55 return;
58 list = map->l_searchlist;
60 /* Call all termination functions at once. */
61 for (i = 0; i < map->l_nsearchlist; ++i)
63 struct link_map *imap = list[i];
64 if (imap->l_opencount == 1 && imap->l_type == lt_loaded
65 && imap->l_info[DT_FINI]
66 /* Skip any half-cooked objects that were never initialized. */
67 && imap->l_init_called)
69 /* When debugging print a message first. */
70 if (_dl_debug_impcalls)
71 _dl_debug_message (1, "\ncalling fini: ", imap->l_name,
72 "\n\n", NULL);
73 /* Call its termination function. */
74 (*(void (*) (void)) ((void *) imap->l_addr
75 + imap->l_info[DT_FINI]->d_un.d_ptr)) ();
79 /* Notify the debugger we are about to remove some loaded objects. */
80 _r_debug.r_state = RT_DELETE;
81 _dl_debug_state ();
83 /* The search list contains a counted reference to each object it
84 points to, the 0th elt being MAP itself. Decrement the reference
85 counts on all the objects MAP depends on. */
86 for (i = 0; i < map->l_nsearchlist; ++i)
87 --list[i]->l_opencount;
89 /* Check each element of the search list to see if all references to
90 it are gone. */
91 for (i = 0; i < map->l_nsearchlist; ++i)
93 struct link_map *imap = list[i];
94 if (imap->l_opencount == 0 && imap->l_type == lt_loaded)
96 /* That was the last reference, and this was a dlopen-loaded
97 object. We can unmap it. */
98 const ElfW(Phdr) *ph;
99 const ElfW(Phdr) *first, *last;
100 ElfW(Addr) mapstart, mapend;
102 if (imap->l_global)
104 /* This object is in the global scope list. Remove it. */
105 struct link_map **tail = _dl_global_scope_end;
107 --tail;
108 while (*tail != imap);
109 while (tail < _dl_global_scope_end)
111 tail[0] = tail[1];
112 ++tail;
114 --_dl_global_scope_end;
117 /* We can unmap all the maps at once. We just have to determine
118 the length and the `munmap' call does the rest. */
119 first = last = NULL;
120 for (ph = imap->l_phdr; ph < imap->l_phdr + imap->l_phnum; ++ph)
121 if (ph->p_type == PT_LOAD)
123 if (first == NULL)
124 first = ph;
125 last = ph;
128 /* Now we have all the information we need for the unmapping.
129 See the method used in `_dl_map_object_from_fd'. */
130 mapstart = first->p_vaddr & ~(first->p_align - 1);
131 mapend = last->p_vaddr + last->p_memsz;
132 __munmap ((caddr_t) (imap->l_addr + mapstart), mapend - mapstart);
134 /* Finally, unlink the data structure and free it. */
135 if (imap->l_prev)
136 imap->l_prev->l_next = imap->l_next;
137 if (imap->l_next)
138 imap->l_next->l_prev = imap->l_prev;
139 if (imap->l_searchlist && imap->l_searchlist != list)
140 free (imap->l_searchlist);
141 free (imap);
145 free (list);
147 /* Notify the debugger those objects are finalized and gone. */
148 _r_debug.r_state = RT_CONSISTENT;
149 _dl_debug_state ();
151 /* Release the lock. */
152 __libc_lock_unlock (_dl_load_lock);