about summary refs log tree commit diff
path: root/elf/get-dynamic-info.h
blob: 0314baf0205a6a8abde1a5894faa29fe83bd89d7 (plain) (blame)
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
/* Read the dynamic section at DYN and fill in INFO with indices DT_*.
   Copyright (C) 2012-2022 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, see
   <https://www.gnu.org/licenses/>.  */

/* Populate dynamic tags in l_info.  */

#ifndef _GET_DYNAMIC_INFO_H
#define _GET_DYNAMIC_INFO_H

#include <assert.h>
#include <dl-machine-rel.h>
#include <libc-diag.h>

static inline void __attribute__ ((unused, always_inline))
elf_get_dynamic_info (struct link_map *l, bool bootstrap,
		      bool static_pie_bootstrap)
{
#if __ELF_NATIVE_CLASS == 32
  typedef Elf32_Word d_tag_utype;
#elif __ELF_NATIVE_CLASS == 64
  typedef Elf64_Xword d_tag_utype;
#endif

#ifndef STATIC_PIE_BOOTSTRAP
  if (!bootstrap && l->l_ld == NULL)
    return;
#endif

  ElfW(Dyn) **info = l->l_info;

  for (ElfW(Dyn) *dyn = l->l_ld; dyn->d_tag != DT_NULL; dyn++)
    {
      d_tag_utype i;

      if ((d_tag_utype) dyn->d_tag < DT_NUM)
	i = dyn->d_tag;
      else if (dyn->d_tag >= DT_LOPROC
	       && dyn->d_tag < DT_LOPROC + DT_THISPROCNUM)
	i = dyn->d_tag - DT_LOPROC + DT_NUM;
      else if ((d_tag_utype) DT_VERSIONTAGIDX (dyn->d_tag) < DT_VERSIONTAGNUM)
	i = VERSYMIDX (dyn->d_tag);
      else if ((d_tag_utype) DT_EXTRATAGIDX (dyn->d_tag) < DT_EXTRANUM)
	i = DT_EXTRATAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
	    + DT_VERSIONTAGNUM;
      else if ((d_tag_utype) DT_VALTAGIDX (dyn->d_tag) < DT_VALNUM)
	i = DT_VALTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
	    + DT_VERSIONTAGNUM + DT_EXTRANUM;
      else if ((d_tag_utype) DT_ADDRTAGIDX (dyn->d_tag) < DT_ADDRNUM)
	i = DT_ADDRTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
	    + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM;
      else
	continue;

      info[i] = dyn;
    }

  /* Don't adjust .dynamic unnecessarily.  */
  if (l->l_addr != 0 && dl_relocate_ld (l))
    {
      ElfW(Addr) l_addr = l->l_addr;

# define ADJUST_DYN_INFO(tag) \
      do								      \
	{								      \
	  if (info[tag] != NULL)					      \
	  info[tag]->d_un.d_ptr += l_addr;				      \
	}								      \
      while (0)

      ADJUST_DYN_INFO (DT_HASH);
      ADJUST_DYN_INFO (DT_PLTGOT);
      ADJUST_DYN_INFO (DT_STRTAB);
      ADJUST_DYN_INFO (DT_SYMTAB);
      ADJUST_DYN_INFO (DT_RELR);
      ADJUST_DYN_INFO (DT_JMPREL);
      ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM));
      ADJUST_DYN_INFO (ADDRIDX (DT_GNU_HASH));
# undef ADJUST_DYN_INFO

      /* DT_RELA/DT_REL are mandatory.  But they may have zero value if
	 there is DT_RELR.  Don't relocate them if they are zero.  */
# define ADJUST_DYN_INFO(tag) \
      do								      \
	if (info[tag] != NULL && info[tag]->d_un.d_ptr != 0)		      \
         info[tag]->d_un.d_ptr += l_addr;				      \
      while (0)

# if ! ELF_MACHINE_NO_RELA
      ADJUST_DYN_INFO (DT_RELA);
# endif
# if ! ELF_MACHINE_NO_REL
      ADJUST_DYN_INFO (DT_REL);
# endif
# undef ADJUST_DYN_INFO
    }
  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_RELR] != NULL)
    assert (info[DT_RELRENT]->d_un.d_val == sizeof (ElfW(Relr)));
  if (bootstrap || static_pie_bootstrap)
    {
      assert (info[DT_RUNPATH] == NULL);
      assert (info[DT_RPATH] == NULL);
    }
  if (bootstrap)
    {
      /* Only the bind now flags are allowed.  */
      assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
	      || (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
      /* Flags must not be set for ld.so.  */
      assert (info[DT_FLAGS] == NULL
	      || (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
    }
  else
    {
      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;

	  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];
	}

      if (info[VERSYMIDX (DT_FLAGS_1)] != NULL)
	{
	  l->l_flags_1 = info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val;
	  if (l->l_flags_1 & DF_1_NODELETE)
	    l->l_nodelete_pending = true;

	  /* Only DT_1_SUPPORTED_MASK bits are supported, and we would like
	     to assert this, but we can't. Users have been setting
	     unsupported DF_1_* flags for a long time and glibc has ignored
	     them. Therefore to avoid breaking existing applications the
	     best we can do is add a warning during debugging with the
	     intent of notifying the user of the problem.  */
	  if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0)
	      && l->l_flags_1 & ~DT_1_SUPPORTED_MASK)
	    _dl_debug_printf ("\nWARNING: Unsupported flag value(s) of 0x%x "
			      "in DT_FLAGS_1.\n",
			     l->l_flags_1 & ~DT_1_SUPPORTED_MASK);

	 if (l->l_flags_1 & DF_1_NOW)
	   info[DT_BIND_NOW] = info[VERSYMIDX (DT_FLAGS_1)];
       }

    if (info[DT_RUNPATH] != NULL)
      /* If both RUNPATH and RPATH are given, the latter is ignored.  */
      info[DT_RPATH] = NULL;
   }
}

#endif