1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
/* dlclose -- Close a handle opened by `dlopen'.
Copyright (C) 1995 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <link.h>
#include <dlfcn.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/mman.h>
#define LOSE(s) _dl_signal_error (0, s)
int
dlclose (void *handle)
{
void doit (void)
{
struct link_map *map = handle;
if (map->l_opencount == 0)
LOSE ("shared object not open");
/* Decrement the reference count. */
--map->l_opencount;
if (map->l_opencount == 0 && map->l_type == lt_loaded)
{
/* That was the last reference, and this was a dlopen-loaded
object. We can unmap it. */
const Elf32_Phdr *ph;
if (map->l_info[DT_FINI])
/* Call its termination function. */
(*(void (*) (void)) ((void *) map->l_addr +
map->l_info[DT_FINI]->d_un.d_ptr)) ();
if (map->l_info[DT_NEEDED])
{
/* Also close all the dependencies. */
const char *strtab
= (void *) map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr;
const Elf32_Dyn *d;
for (d = map->l_ld; d->d_tag != DT_NULL; ++d)
if (d->d_tag == DT_NEEDED)
{
/* It must already be open, since this one needed it;
so dlopen will just find us its `struct link_map'
and bump its reference count. */
struct link_map *o, *dep
= dlopen (strtab + d->d_un.d_val, RTLD_LAZY);
--dep->l_opencount; /* Lose the ref from that dlopen. */
/* Now we have the handle; we can close it for real. */
o = map;
map = dep;
doit ();
map = o;
}
}
/* Unmap the segments. */
for (ph = map->l_phdr; ph < &map->l_phdr[map->l_phnum]; ++ph)
if (ph->p_type == PT_LOAD)
{
Elf32_Addr mapstart = ph->p_vaddr & ~(ph->p_align - 1);
Elf32_Addr mapend = ((ph->p_vaddr + ph->p_memsz
+ ph->p_align - 1)
& ~(ph->p_align - 1));
munmap ((caddr_t) mapstart, mapend - mapstart);
}
/* Finally, unlink the data structure and free it. */
map->l_prev->l_next = map->l_next;
if (map->l_next)
map->l_next->l_prev = map->l_prev;
free (map);
}
}
return _dlerror_run (doit) ? -1 : 0;
}
|
