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
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
|
/* Call the termination functions of loaded shared objects.
Copyright (C) 1995,96,1998-2002,2004 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <alloca.h>
#include <assert.h>
#include <string.h>
#include <ldsodefs.h>
/* Type of the constructor functions. */
typedef void (*fini_t) (void);
void
internal_function
_dl_fini (void)
{
/* Lots of fun ahead. We have to call the destructors for all still
loaded objects, in all namespaces. The problem is that the ELF
specification now demands that dependencies between the modules
are taken into account. I.e., the destructor for a module is
called before the ones for any of its dependencies.
To make things more complicated, we cannot simply use the reverse
order of the constructors. Since the user might have loaded objects
using `dlopen' there are possibly several other modules with its
dependencies to be taken into account. Therefore we have to start
determining the order of the modules once again from the beginning. */
struct link_map **maps = NULL;
size_t maps_size = 0;
/* We run the destructors of the main namespaces last. As for the
other namespaces, we pick run the destructors in them in reverse
order of the namespace ID. */
for (Lmid_t cnt = DL_NNS - 1; cnt >= 0; --cnt)
{
/* Protect against concurrent loads and unloads. */
__rtld_lock_lock_recursive (GL(dl_load_lock));
unsigned int nmaps = 0;
unsigned int nloaded = GL(dl_ns)[cnt]._ns_nloaded;
/* No need to do anything for empty namespaces or those used for
auditing DSOs. */
if (nloaded == 0 || GL(dl_ns)[cnt]._ns_loaded->l_auditing)
goto out;
/* XXX Could it be (in static binaries) that there is no object
loaded? */
assert (cnt != LM_ID_BASE || nloaded > 0);
/* Now we can allocate an array to hold all the pointers and copy
the pointers in. */
if (maps_size < nloaded * sizeof (struct link_map *))
{
if (maps_size == 0)
{
maps_size = nloaded * sizeof (struct link_map *);
maps = (struct link_map **) alloca (maps_size);
}
else
maps = (struct link_map **)
extend_alloca (maps, maps_size,
nloaded * sizeof (struct link_map *));
}
unsigned int i;
struct link_map *l;
assert (nloaded != 0 || GL(dl_ns)[cnt]._ns_loaded == NULL);
for (l = GL(dl_ns)[cnt]._ns_loaded, i = 0; l != NULL; l = l->l_next)
/* Do not handle ld.so in secondary namespaces. */
if (l == l->l_real)
{
assert (i < nloaded);
maps[i++] = l;
/* Bump l_opencount of all objects so that they are not
dlclose()ed from underneath us. */
++l->l_opencount;
}
assert (cnt != LM_ID_BASE || i == nloaded);
assert (cnt == LM_ID_BASE || i == nloaded || i == nloaded - 1);
nmaps = i;
if (nmaps != 0)
{
/* Now we have to do the sorting. */
l = GL(dl_ns)[cnt]._ns_loaded;
if (cnt == LM_ID_BASE)
/* The main executable always comes first. */
l = l->l_next;
for (; l != NULL; l = l->l_next)
/* Do not handle ld.so in secondary namespaces. */
if (l == l->l_real)
{
/* Find the place in the 'maps' array. */
unsigned int j;
for (j = cnt == LM_ID_BASE ? 1 : 0; maps[j] != l; ++j)
assert (j < nmaps);
/* Find all object for which the current one is a dependency
and move the found object (if necessary) in front. */
for (unsigned int k = j + 1; k < nmaps; ++k)
{
struct link_map **runp = maps[k]->l_initfini;
if (runp != NULL)
{
while (*runp != NULL)
if (*runp == l)
{
struct link_map *here = maps[k];
/* Move it now. */
memmove (&maps[j] + 1,
&maps[j],
(k - j) * sizeof (struct link_map *));
maps[j++] = here;
break;
}
else
++runp;
}
if (__builtin_expect (maps[k]->l_reldeps != NULL, 0))
{
unsigned int m = maps[k]->l_reldepsact;
struct link_map **relmaps = maps[k]->l_reldeps;
while (m-- > 0)
{
if (relmaps[m] == l)
{
struct link_map *here = maps[k];
/* Move it now. */
memmove (&maps[j] + 1,
&maps[j],
(k - j) * sizeof (struct link_map *));
maps[j] = here;
break;
}
}
}
}
}
}
/* We do not rely on the linked list of loaded object anymore from
this point on. We have our own list here (maps). The various
members of this list cannot vanish since the open count is too
high and will be decremented in this loop. So we release the
lock so that some code which might be called from a destructor
can directly or indirectly access the lock. */
out:
__rtld_lock_unlock_recursive (GL(dl_load_lock));
/* 'maps' now contains the objects in the right order. Now call the
destructors. We have to process this array from the front. */
for (i = 0; i < nmaps; ++i)
{
l = maps[i];
if (l->l_init_called)
{
/* Make sure nothing happens if we are called twice. */
l->l_init_called = 0;
/* Is there a destructor function? */
if (l->l_info[DT_FINI_ARRAY] != NULL
|| l->l_info[DT_FINI] != NULL)
{
/* When debugging print a message first. */
if (__builtin_expect (GLRO(dl_debug_mask)
& DL_DEBUG_IMPCALLS, 0))
_dl_debug_printf ("\ncalling fini: %s [%lu]\n\n",
l->l_name[0] ? l->l_name : rtld_progname,
cnt);
/* First see whether an array is given. */
if (l->l_info[DT_FINI_ARRAY] != NULL)
{
ElfW(Addr) *array =
(ElfW(Addr) *) (l->l_addr
+ l->l_info[DT_FINI_ARRAY]->d_un.d_ptr);
unsigned int i = (l->l_info[DT_FINI_ARRAYSZ]->d_un.d_val
/ sizeof (ElfW(Addr)));
while (i-- > 0)
((fini_t) array[i]) ();
}
/* Next try the old-style destructor. */
if (l->l_info[DT_FINI] != NULL)
((fini_t) DL_DT_FINI_ADDRESS (l, l->l_addr + l->l_info[DT_FINI]->d_un.d_ptr)) ();
}
#ifdef SHARED
/* Auditing checkpoint: another object closed. */
if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
{
struct audit_ifaces *afct = GLRO(dl_audit);
for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
{
if (afct->objclose != NULL)
/* Return value is ignored. */
(void) afct->objclose (&l->l_audit[cnt].cookie);
afct = afct->next;
}
}
#endif
}
/* Correct the previous increment. */
--l->l_opencount;
}
}
if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_STATISTICS, 0))
_dl_debug_printf ("\nruntime linker statistics:\n"
" final number of relocations: %lu\n"
"final number of relocations from cache: %lu\n",
GL(dl_num_relocations),
GL(dl_num_cache_relocations));
}
|
