aboutsummaryrefslogtreecommitdiff
path: root/elf/dynamic-link.h
blob: 6a8871ea9c9c6c31b59f24640a2a9a6720ee121b (plain)
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
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
/* Inline functions for dynamic linking.
   Copyright (C) 1995,96,97,98,99,2000,2001,2002 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 <elf.h>
#include <dl-machine.h>
#include <assert.h>

#ifndef VERSYMIDX
# define VERSYMIDX(sym)	(DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (sym))
#endif


/* Read the dynamic section at DYN and fill in INFO with indices DT_*.  */

static inline void __attribute__ ((unused, always_inline))
elf_get_dynamic_info (struct link_map *l)
{
  ElfW(Dyn) *dyn = l->l_ld;
  ElfW(Dyn) **info;

#ifndef RTLD_BOOTSTRAP
  if (dyn == NULL)
    return;
#endif

  info = l->l_info;

  while (dyn->d_tag != DT_NULL)
    {
      if (dyn->d_tag < DT_NUM)
	info[dyn->d_tag] = dyn;
      else if (dyn->d_tag >= DT_LOPROC &&
	       dyn->d_tag < DT_LOPROC + DT_THISPROCNUM)
	info[dyn->d_tag - DT_LOPROC + DT_NUM] = dyn;
      else if ((Elf32_Word) DT_VERSIONTAGIDX (dyn->d_tag) < DT_VERSIONTAGNUM)
	info[VERSYMIDX (dyn->d_tag)] = dyn;
      else if ((Elf32_Word) DT_EXTRATAGIDX (dyn->d_tag) < DT_EXTRANUM)
	info[DT_EXTRATAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
	     + DT_VERSIONTAGNUM] = dyn;
      else if ((Elf32_Word) DT_VALTAGIDX (dyn->d_tag) < DT_VALNUM)
	info[DT_VALTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
	     + DT_VERSIONTAGNUM + DT_EXTRANUM] = dyn;
      else if ((Elf32_Word) DT_ADDRTAGIDX (dyn->d_tag) < DT_ADDRNUM)
	info[DT_ADDRTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
	     + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM] = dyn;
      ++dyn;
    }
#ifndef DL_RO_DYN_SECTION
  /* Don't adjust .dynamic unnecessarily.  */
  if (l->l_addr != 0)
    {
      ElfW(Addr) l_addr = l->l_addr;

      if (info[DT_HASH] != NULL)
	info[DT_HASH]->d_un.d_ptr += l_addr;
      if (info[DT_PLTGOT] != NULL)
	info[DT_PLTGOT]->d_un.d_ptr += l_addr;
      if (info[DT_STRTAB] != NULL)
	info[DT_STRTAB]->d_un.d_ptr += l_addr;
      if (info[DT_SYMTAB] != NULL)
	info[DT_SYMTAB]->d_un.d_ptr += l_addr;
# if ! ELF_MACHINE_NO_RELA
      if (info[DT_RELA] != NULL)
	info[DT_RELA]->d_un.d_ptr += l_addr;
# endif
# if ! ELF_MACHINE_NO_REL
      if (info[DT_REL] != NULL)
	info[DT_REL]->d_un.d_ptr += l_addr;
# endif
      if (info[DT_JMPREL] != NULL)
	info[DT_JMPREL]->d_un.d_ptr += l_addr;
      if (info[VERSYMIDX (DT_VERSYM)] != NULL)
	info[VERSYMIDX (DT_VERSYM)]->d_un.d_ptr += l_addr;
    }
#endif
  if (info[DT_PLTREL] != NULL)
    {
#if ELF_MACHINE_NO_RELA
      assert (info[DT_PLTREL]->d_un.d_val == DT_REL);
#elif ELF_MACHINE_NO_REL
      assert (info[DT_PLTREL]->d_un.d_val == DT_RELA);
#else
      assert (info[DT_PLTREL]->d_un.d_val == DT_REL
	      || info[DT_PLTREL]->d_un.d_val == DT_RELA);
#endif
    }
#if ! ELF_MACHINE_NO_RELA
  if (info[DT_RELA] != NULL)
    assert (info[DT_RELAENT]->d_un.d_val == sizeof (ElfW(Rela)));
# endif
# if ! ELF_MACHINE_NO_REL
  if (info[DT_REL] != NULL)
    assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel)));
#endif
  if (info[DT_FLAGS] != NULL)
    {
      /* Flags are used.  Translate to the old form where available.
	 Since these l_info entries are only tested for NULL pointers it
	 is ok if they point to the DT_FLAGS entry.  */
      l->l_flags = info[DT_FLAGS]->d_un.d_val;
#ifdef RTLD_BOOTSTRAP
      /* These three flags must not be set for ld.so.  */
      assert ((l->l_flags & (DF_SYMBOLIC | DF_TEXTREL | DF_BIND_NOW)) == 0);
#else
      if (l->l_flags & DF_SYMBOLIC)
	info[DT_SYMBOLIC] = info[DT_FLAGS];
      if (l->l_flags & DF_TEXTREL)
	info[DT_TEXTREL] = info[DT_FLAGS];
      if (l->l_flags & DF_BIND_NOW)
	info[DT_BIND_NOW] = info[DT_FLAGS];
#endif
    }
  if (info[VERSYMIDX (DT_FLAGS_1)] != NULL)
    l->l_flags_1 = info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val;
#ifdef RTLD_BOOTSTRAP
  /* The dynamic linker should have none of these set.  */
  assert (info[DT_RUNPATH] == NULL);
  assert (info[DT_RPATH] == NULL);
#else
  if (info[DT_RUNPATH] != NULL)
    /* If both RUNPATH and RPATH are given, the latter is ignored.  */
    info[DT_RPATH] = NULL;
#endif
}

#ifdef RESOLVE

# ifdef RTLD_BOOTSTRAP
#  define ELF_DURING_STARTUP (1)
# else
#  define ELF_DURING_STARTUP (0)
# endif

/* Get the definitions of `elf_dynamic_do_rel' and `elf_dynamic_do_rela'.
   These functions are almost identical, so we use cpp magic to avoid
   duplicating their code.  It cannot be done in a more general function
   because we must be able to completely inline.  */

/* On some machines, notably SPARC, DT_REL* includes DT_JMPREL in its
   range.  Note that according to the ELF spec, this is completely legal!
   But conditionally define things so that on machines we know this will
   not happen we do something more optimal.  */

# ifdef ELF_MACHINE_PLTREL_OVERLAP
#  define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, do_lazy, test_rel) \
  do {									      \
    struct { ElfW(Addr) start, size; int lazy; } ranges[3];		      \
    int ranges_index;							      \
									      \
    ranges[0].lazy = ranges[2].lazy = 0;				      \
    ranges[1].lazy = 1;							      \
    ranges[0].size = ranges[1].size = ranges[2].size = 0;		      \
									      \
    if ((map)->l_info[DT_##RELOC])					      \
      {									      \
	ranges[0].start = D_PTR ((map), l_info[DT_##RELOC]);		      \
	ranges[0].size = (map)->l_info[DT_##RELOC##SZ]->d_un.d_val;	      \
      }									      \
									      \
    if ((do_lazy)							      \
	&& (map)->l_info[DT_PLTREL]					      \
	&& (!test_rel || (map)->l_info[DT_PLTREL]->d_un.d_val == DT_##RELOC)) \
      {									      \
	ranges[1].start = D_PTR ((map), l_info[DT_JMPREL]);		      \
	ranges[1].size = (map)->l_info[DT_PLTRELSZ]->d_un.d_val;	      \
	ranges[2].start = ranges[1].start + ranges[1].size;		      \
	ranges[2].size = ranges[0].start + ranges[0].size - ranges[2].start;  \
	ranges[0].size = ranges[1].start - ranges[0].start;		      \
      }									      \
									      \
    for (ranges_index = 0; ranges_index < 3; ++ranges_index)		      \
      elf_dynamic_do_##reloc ((map),					      \
			      ranges[ranges_index].start,		      \
			      ranges[ranges_index].size,		      \
			      ranges[ranges_index].lazy);		      \
  } while (0)
# else
#  define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, do_lazy, test_rel) \
  do {									      \
    struct { ElfW(Addr) start, size; int lazy; } ranges[2];		      \
    ranges[0].lazy = 0;							      \
    ranges[0].size = ranges[1].size = 0;				      \
    ranges[0].start = 0;						      \
									      \
    if ((map)->l_info[DT_##RELOC])					      \
      {									      \
	ranges[0].start = D_PTR ((map), l_info[DT_##RELOC]);		      \
	ranges[0].size = (map)->l_info[DT_##RELOC##SZ]->d_un.d_val;	      \
      }									      \
    if ((map)->l_info[DT_PLTREL]					      \
	&& (!test_rel || (map)->l_info[DT_PLTREL]->d_un.d_val == DT_##RELOC)) \
      {									      \
	ElfW(Addr) start = D_PTR ((map), l_info[DT_JMPREL]);		      \
									      \
	if (! ELF_DURING_STARTUP					      \
	    && ((do_lazy)						      \
		/* This test does not only detect whether the relocation      \
		   sections are in the right order, it also checks whether    \
		   there is a DT_REL/DT_RELA section.  */		      \
		|| ranges[0].start + ranges[0].size != start))		      \
	  {								      \
	    ranges[1].start = start;					      \
	    ranges[1].size = (map)->l_info[DT_PLTRELSZ]->d_un.d_val;	      \
	    ranges[1].lazy = (do_lazy);					      \
	  }								      \
	else								      \
	  {								      \
	    /* Combine processing the sections.  */			      \
	    assert (ranges[0].start + ranges[0].size == start);		      \
	    ranges[0].size += (map)->l_info[DT_PLTRELSZ]->d_un.d_val;	      \
	  }								      \
      }									      \
									      \
    if (ELF_DURING_STARTUP)						      \
      elf_dynamic_do_##reloc ((map), ranges[0].start, ranges[0].size, 0);     \
    else								      \
      {									      \
	int ranges_index;						      \
	for (ranges_index = 0; ranges_index < 2; ++ranges_index)	      \
	  elf_dynamic_do_##reloc ((map),				      \
				  ranges[ranges_index].start,		      \
				  ranges[ranges_index].size,		      \
				  ranges[ranges_index].lazy);		      \
      }									      \
  } while (0)
# endif

# if ELF_MACHINE_NO_REL || ELF_MACHINE_NO_RELA
#  define _ELF_CHECK_REL 0
# else
#  define _ELF_CHECK_REL 1
# endif

# if ! ELF_MACHINE_NO_REL
#  include "do-rel.h"
#  define ELF_DYNAMIC_DO_REL(map, lazy) \
  _ELF_DYNAMIC_DO_RELOC (REL, rel, map, lazy, _ELF_CHECK_REL)
# else
#  define ELF_DYNAMIC_DO_REL(map, lazy) /* Nothing to do.  */
# endif

# if ! ELF_MACHINE_NO_RELA
#  define DO_RELA
#  include "do-rel.h"
#  define ELF_DYNAMIC_DO_RELA(map, lazy) \
  _ELF_DYNAMIC_DO_RELOC (RELA, rela, map, lazy, _ELF_CHECK_REL)
# else
#  define ELF_DYNAMIC_DO_RELA(map, lazy) /* Nothing to do.  */
# endif

/* This can't just be an inline function because GCC is too dumb
   to inline functions containing inlines themselves.  */
# define ELF_DYNAMIC_RELOCATE(map, lazy, consider_profile) \
  do {									      \
    int edr_lazy = elf_machine_runtime_setup ((map), (lazy),		      \
					      (consider_profile));	      \
    ELF_DYNAMIC_DO_REL ((map), edr_lazy);				      \
    ELF_DYNAMIC_DO_RELA ((map), edr_lazy);				      \
  } while (0)

#endif