1 /* Relocate a shared object and resolve its references to other loaded objects.
2 Copyright (C) 1995,96,97,98,99,2000,2001 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 Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the 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 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26 #include <sys/param.h>
27 #include <sys/types.h>
28 #include "dynamic-link.h"
30 /* Statistics function. */
31 unsigned long int _dl_num_cache_relocations
;
35 _dl_relocate_object (struct link_map
*l
, struct r_scope_elem
*scope
[],
36 int lazy
, int consider_profiling
)
41 /* If DT_BIND_NOW is set relocate all references in this object. We
42 do not do this if we are profiling, of course. */
43 if (!consider_profiling
44 && __builtin_expect (l
->l_info
[DT_BIND_NOW
] != NULL
, 0))
47 if (__builtin_expect (_dl_debug_mask
& DL_DEBUG_RELOC
, 0))
48 _dl_printf ("\nrelocation processing: %s%s\n",
49 l
->l_name
[0] ? l
->l_name
: _dl_argv
[0], lazy
? " (lazy)" : "");
51 if (__builtin_expect (l
->l_info
[DT_TEXTREL
] != NULL
, 0))
53 /* Bletch. We must make read-only segments writable
54 long enough to relocate them. */
56 for (ph
= l
->l_phdr
; ph
< &l
->l_phdr
[l
->l_phnum
]; ++ph
)
57 if (ph
->p_type
== PT_LOAD
&& (ph
->p_flags
& PF_W
) == 0)
59 caddr_t mapstart
= ((caddr_t
) l
->l_addr
+
60 (ph
->p_vaddr
& ~(_dl_pagesize
- 1)));
61 caddr_t mapend
= ((caddr_t
) l
->l_addr
+
62 ((ph
->p_vaddr
+ ph
->p_memsz
+ _dl_pagesize
- 1)
63 & ~(_dl_pagesize
- 1)));
64 if (__builtin_expect (__mprotect (mapstart
, mapend
- mapstart
,
65 PROT_READ
|PROT_WRITE
), 0) < 0)
66 _dl_signal_error (errno
, l
->l_name
, NULL
, N_("\
67 cannot make segment writable for relocation"));
72 /* Do the actual relocation of the object's GOT and other data. */
74 /* String table object symbols. */
75 const char *strtab
= (const void *) D_PTR (l
, l_info
[DT_STRTAB
]);
77 /* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */
78 #define RESOLVE_MAP(ref, version, r_type) \
79 (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
80 ? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0) \
81 && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class) \
82 ? (++_dl_num_cache_relocations, \
83 (*ref) = l->l_lookup_cache.ret, \
84 l->l_lookup_cache.value) \
86 int _tc = elf_machine_type_class (r_type); \
87 l->l_lookup_cache.type_class = _tc; \
88 l->l_lookup_cache.sym = (*ref); \
89 _lr = ((version) != NULL && (version)->hash != 0 \
90 ? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \
93 : _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), \
95 l->l_lookup_cache.ret = (*ref); \
96 l->l_lookup_cache.value = _lr; })) \
98 #define RESOLVE(ref, version, r_type) \
99 (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
100 ? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0) \
101 && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class) \
102 ? (++_dl_num_cache_relocations, \
103 (*ref) = l->l_lookup_cache.ret, \
104 l->l_lookup_cache.value) \
106 int _tc = elf_machine_type_class (r_type); \
107 l->l_lookup_cache.type_class = _tc; \
108 l->l_lookup_cache.sym = (*ref); \
109 _lr = ((version) != NULL && (version)->hash != 0 \
110 ? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \
113 : _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), \
115 l->l_lookup_cache.ret = (*ref); \
116 l->l_lookup_cache.value = _lr; })) \
119 #include "dynamic-link.h"
121 ELF_DYNAMIC_RELOCATE (l
, lazy
, consider_profiling
);
123 if (__builtin_expect (consider_profiling
, 0))
125 /* Allocate the array which will contain the already found
126 relocations. If the shared object lacks a PLT (for example
127 if it only contains lead function) the l_info[DT_PLTRELSZ]
129 if (l
->l_info
[DT_PLTRELSZ
] == NULL
)
130 _dl_fatal_printf ("%s: profiler found no PLTREL in object %s\n",
131 _dl_argv
[0] ?: "<program name unknown>",
135 (ElfW(Addr
) *) calloc (sizeof (ElfW(Addr
)),
136 l
->l_info
[DT_PLTRELSZ
]->d_un
.d_val
);
137 if (l
->l_reloc_result
== NULL
)
139 %s: profiler out of memory shadowing PLTREL of %s\n",
140 _dl_argv
[0] ?: "<program name unknown>",
145 /* Mark the object so we know this work has been done. */
148 /* DT_TEXTREL is now in level 2 and might phase out at some time.
149 But we rewrite the DT_FLAGS entry to make testing easier and
150 therefore it will be available at all time. */
151 if (__builtin_expect (l
->l_info
[DT_TEXTREL
] != NULL
, 0))
153 /* Undo the protection change we made before relocating. */
154 const ElfW(Phdr
) *ph
;
155 for (ph
= l
->l_phdr
; ph
< &l
->l_phdr
[l
->l_phnum
]; ++ph
)
156 if (ph
->p_type
== PT_LOAD
&& (ph
->p_flags
& PF_W
) == 0)
158 caddr_t mapstart
= ((caddr_t
) l
->l_addr
+
159 (ph
->p_vaddr
& ~(_dl_pagesize
- 1)));
160 caddr_t mapend
= ((caddr_t
) l
->l_addr
+
161 ((ph
->p_vaddr
+ ph
->p_memsz
+ _dl_pagesize
- 1)
162 & ~(_dl_pagesize
- 1)));
163 extern unsigned char _dl_pf_to_prot
[8];
166 if ((PF_R
| PF_W
| PF_X
) == 7
167 && (PROT_READ
| PROT_WRITE
| PROT_EXEC
) == 7)
168 prot
= _dl_pf_to_prot
[ph
->p_flags
& (PF_R
| PF_X
)];
172 if (ph
->p_flags
& PF_R
)
174 if (ph
->p_flags
& PF_X
)
178 if (__builtin_expect (__mprotect (mapstart
, mapend
- mapstart
,
180 _dl_signal_error (errno
, l
->l_name
, NULL
,
181 N_("can't restore segment prot after reloc"));
184 CLEAR_CACHE (mapstart
, mapend
);
190 #include "../stdio-common/_itoa.h"
191 #define DIGIT(b) _itoa_lower_digits[(b) & 0xf];
195 _dl_reloc_bad_type (struct link_map
*map
, uint_fast8_t type
, int plt
)
197 extern const char _itoa_lower_digits
[];
200 /* XXX We cannot translate the message. */
201 static char msg
[] = "unexpected PLT reloc type 0x??";
202 msg
[sizeof msg
- 3] = DIGIT(type
>> 4);
203 msg
[sizeof msg
- 2] = DIGIT(type
);
204 _dl_signal_error (0, map
->l_name
, NULL
, msg
);
208 /* XXX We cannot translate the message. */
209 static char msg
[] = "unexpected reloc type 0x??";
210 msg
[sizeof msg
- 3] = DIGIT(type
>> 4);
211 msg
[sizeof msg
- 2] = DIGIT(type
);
212 _dl_signal_error (0, map
->l_name
, NULL
, msg
);