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)
43 struct textrels *next;
45 /* Initialize it to make the compiler happy. */
46 const char *errstring = NULL;
51 /* If DT_BIND_NOW is set relocate all references in this object. We
52 do not do this if we are profiling, of course. */
53 if (!consider_profiling
54 && __builtin_expect (l->l_info[DT_BIND_NOW] != NULL, 0))
57 if (__builtin_expect (_dl_debug_mask & DL_DEBUG_RELOC, 0))
58 _dl_printf ("\nrelocation processing: %s%s\n",
59 l->l_name[0] ? l->l_name : _dl_argv[0], lazy ? " (lazy)" : "");
61 /* DT_TEXTREL is now in level 2 and might phase out at some time.
62 But we rewrite the DT_FLAGS entry to a DT_TEXTREL entry to make
63 testing easier and therefore it will be available at all time. */
64 if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0))
66 /* Bletch. We must make read-only segments writable
67 long enough to relocate them. */
69 for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
70 if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
72 struct textrels *newp;
74 newp = (struct textrels *) alloca (sizeof (*newp));
75 newp->len = (((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
76 & ~(_dl_pagesize - 1))
77 - (ph->p_vaddr & ~(_dl_pagesize - 1)));
78 newp->start = ((ph->p_vaddr & ~(_dl_pagesize - 1))
79 + (caddr_t) l->l_addr);
81 if (mprotect (newp->start, newp->len, PROT_READ|PROT_WRITE) < 0)
83 errstring = N_("cannot make segment writable for relocation");
85 _dl_signal_error (errno, l->l_name, NULL, errstring);
88 #if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
89 newp->prot = (PF_TO_PROT
90 >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
93 if (ph->p_flags & PF_R)
94 newp->prot |= PROT_READ;
95 if (ph->p_flags & PF_W)
96 newp->prot |= PROT_WRITE;
97 if (ph->p_flags & PF_X)
98 newp->prot |= PROT_EXEC;
100 newp->next = textrels;
106 /* Do the actual relocation of the object's GOT and other data. */
108 /* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */
109 #define RESOLVE_MAP(ref, version, r_type, scope) \
110 (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
111 ? ((__builtin_expect ((*ref) == map->l_lookup_cache.sym, 0) \
112 && elf_machine_type_class (r_type) == map->l_lookup_cache.type_class)\
113 ? (++_dl_num_cache_relocations, \
114 (*ref) = map->l_lookup_cache.ret, \
115 map->l_lookup_cache.value) \
117 int _tc = elf_machine_type_class (r_type); \
118 map->l_lookup_cache.type_class = _tc; \
119 map->l_lookup_cache.sym = (*ref); \
120 _lr = ((version) != NULL && (version)->hash != 0 \
121 ? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \
124 : _dl_lookup_symbol (strtab + (*ref)->st_name, map, (ref),\
126 map->l_lookup_cache.ret = (*ref); \
127 map->l_lookup_cache.value = _lr; })) \
129 #define RESOLVE(ref, version, r_type, scope) \
130 (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
131 ? ((__builtin_expect ((*ref) == map->l_lookup_cache.sym, 0) \
132 && elf_machine_type_class (r_type) == map->l_lookup_cache.type_class)\
133 ? (++_dl_num_cache_relocations, \
134 (*ref) = map->l_lookup_cache.ret, \
135 map->l_lookup_cache.value) \
137 int _tc = elf_machine_type_class (r_type); \
138 map->l_lookup_cache.type_class = _tc; \
139 map->l_lookup_cache.sym = (*ref); \
140 _lr = ((version) != NULL && (version)->hash != 0 \
141 ? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \
144 : _dl_lookup_symbol (strtab + (*ref)->st_name, map, (ref),\
146 map->l_lookup_cache.ret = (*ref); \
147 map->l_lookup_cache.value = _lr; })) \
150 #include "dynamic-link.h"
152 ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling);
154 if (__builtin_expect (consider_profiling, 0))
156 /* Allocate the array which will contain the already found
157 relocations. If the shared object lacks a PLT (for example
158 if it only contains lead function) the l_info[DT_PLTRELSZ]
160 if (l->l_info[DT_PLTRELSZ] == NULL)
162 errstring = N_("%s: profiler found no PLTREL in object %s\n");
164 _dl_fatal_printf (errstring,
165 _dl_argv[0] ?: "<program name unknown>",
170 (ElfW(Addr) *) calloc (sizeof (ElfW(Addr)),
171 l->l_info[DT_PLTRELSZ]->d_un.d_val);
172 if (l->l_reloc_result == NULL)
175 %s: profiler out of memory shadowing PLTREL of %s\n");
181 /* Mark the object so we know this work has been done. */
184 /* Undo the segment protection changes. */
185 while (__builtin_expect (textrels != NULL, 0))
187 if (mprotect (textrels->start, textrels->len, textrels->prot) < 0)
189 errstring = N_("cannot restore segment prot after reloc");
193 textrels = textrels->next;
197 #include <machine/dl-machine.h>
201 _dl_reloc_bad_type (struct link_map *map, unsigned int type, int plt)
203 /* XXX We cannot translate these messages. */
204 static const char msg[2][32] = { "unexpected reloc type",
205 "unexpected PLT reloc type" };
206 char msgbuf[sizeof (msg[0])];
208 strcpy (msgbuf, msg[plt]);
210 _dl_signal_error (0, map->l_name, NULL, msgbuf);