MicroBlaze: Update kernel-features.h for syscalls added in 3.15
[glibc.git] / elf / dl-reloc.c
blobd2c6dac69e479b1120b490162b4eccc8ca044554
1 /* Relocate a shared object and resolve its references to other loaded objects.
2 Copyright (C) 1995-2014 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, see
17 <http://www.gnu.org/licenses/>. */
19 #include <errno.h>
20 #include <libintl.h>
21 #include <stdlib.h>
22 #include <unistd.h>
23 #include <ldsodefs.h>
24 #include <sys/mman.h>
25 #include <sys/param.h>
26 #include <sys/types.h>
27 #include <_itoa.h>
28 #include "dynamic-link.h"
30 /* Statistics function. */
31 #ifdef SHARED
32 # define bump_num_cache_relocations() ++GL(dl_num_cache_relocations)
33 #else
34 # define bump_num_cache_relocations() ((void) 0)
35 #endif
38 /* We are trying to perform a static TLS relocation in MAP, but it was
39 dynamically loaded. This can only work if there is enough surplus in
40 the static TLS area already allocated for each running thread. If this
41 object's TLS segment is too big to fit, we fail. If it fits,
42 we set MAP->l_tls_offset and return.
43 This function intentionally does not return any value but signals error
44 directly, as static TLS should be rare and code handling it should
45 not be inlined as much as possible. */
46 int
47 internal_function
48 _dl_try_allocate_static_tls (struct link_map *map)
50 /* If we've already used the variable with dynamic access, or if the
51 alignment requirements are too high, fail. */
52 if (map->l_tls_offset == FORCED_DYNAMIC_TLS_OFFSET
53 || map->l_tls_align > GL(dl_tls_static_align))
55 fail:
56 return -1;
59 #if TLS_TCB_AT_TP
60 size_t freebytes = GL(dl_tls_static_size) - GL(dl_tls_static_used);
61 if (freebytes < TLS_TCB_SIZE)
62 goto fail;
63 freebytes -= TLS_TCB_SIZE;
65 size_t blsize = map->l_tls_blocksize + map->l_tls_firstbyte_offset;
66 if (freebytes < blsize)
67 goto fail;
69 size_t n = (freebytes - blsize) / map->l_tls_align;
71 size_t offset = GL(dl_tls_static_used) + (freebytes - n * map->l_tls_align
72 - map->l_tls_firstbyte_offset);
74 map->l_tls_offset = GL(dl_tls_static_used) = offset;
75 #elif TLS_DTV_AT_TP
76 /* dl_tls_static_used includes the TCB at the beginning. */
77 size_t offset = (((GL(dl_tls_static_used)
78 - map->l_tls_firstbyte_offset
79 + map->l_tls_align - 1) & -map->l_tls_align)
80 + map->l_tls_firstbyte_offset);
81 size_t used = offset + map->l_tls_blocksize;
83 if (used > GL(dl_tls_static_size))
84 goto fail;
86 map->l_tls_offset = offset;
87 map->l_tls_firstbyte_offset = GL(dl_tls_static_used);
88 GL(dl_tls_static_used) = used;
89 #else
90 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
91 #endif
93 /* If the object is not yet relocated we cannot initialize the
94 static TLS region. Delay it. */
95 if (map->l_real->l_relocated)
97 #ifdef SHARED
98 if (__builtin_expect (THREAD_DTV()[0].counter != GL(dl_tls_generation),
99 0))
100 /* Update the slot information data for at least the generation of
101 the DSO we are allocating data for. */
102 (void) _dl_update_slotinfo (map->l_tls_modid);
103 #endif
105 GL(dl_init_static_tls) (map);
107 else
108 map->l_need_tls_init = 1;
110 return 0;
113 void
114 internal_function __attribute_noinline__
115 _dl_allocate_static_tls (struct link_map *map)
117 if (map->l_tls_offset == FORCED_DYNAMIC_TLS_OFFSET
118 || _dl_try_allocate_static_tls (map))
120 _dl_signal_error (0, map->l_name, NULL, N_("\
121 cannot allocate memory in static TLS block"));
125 /* Initialize static TLS area and DTV for current (only) thread.
126 libpthread implementations should provide their own hook
127 to handle all threads. */
128 void
129 _dl_nothread_init_static_tls (struct link_map *map)
131 #if TLS_TCB_AT_TP
132 void *dest = (char *) THREAD_SELF - map->l_tls_offset;
133 #elif TLS_DTV_AT_TP
134 void *dest = (char *) THREAD_SELF + map->l_tls_offset + TLS_PRE_TCB_SIZE;
135 #else
136 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
137 #endif
139 /* Fill in the DTV slot so that a later LD/GD access will find it. */
140 dtv_t *dtv = THREAD_DTV ();
141 assert (map->l_tls_modid <= dtv[-1].counter);
142 dtv[map->l_tls_modid].pointer.val = dest;
143 dtv[map->l_tls_modid].pointer.is_static = true;
145 /* Initialize the memory. */
146 memset (__mempcpy (dest, map->l_tls_initimage, map->l_tls_initimage_size),
147 '\0', map->l_tls_blocksize - map->l_tls_initimage_size);
151 void
152 _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
153 int reloc_mode, int consider_profiling)
155 struct textrels
157 caddr_t start;
158 size_t len;
159 int prot;
160 struct textrels *next;
161 } *textrels = NULL;
162 /* Initialize it to make the compiler happy. */
163 const char *errstring = NULL;
164 int lazy = reloc_mode & RTLD_LAZY;
165 int skip_ifunc = reloc_mode & __RTLD_NOIFUNC;
167 #ifdef SHARED
168 /* If we are auditing, install the same handlers we need for profiling. */
169 if ((reloc_mode & __RTLD_AUDIT) == 0)
170 consider_profiling |= GLRO(dl_audit) != NULL;
171 #elif defined PROF
172 /* Never use dynamic linker profiling for gprof profiling code. */
173 # define consider_profiling 0
174 #endif
176 if (l->l_relocated)
177 return;
179 /* If DT_BIND_NOW is set relocate all references in this object. We
180 do not do this if we are profiling, of course. */
181 // XXX Correct for auditing?
182 if (!consider_profiling
183 && __builtin_expect (l->l_info[DT_BIND_NOW] != NULL, 0))
184 lazy = 0;
186 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_RELOC))
187 _dl_debug_printf ("\nrelocation processing: %s%s\n",
188 DSO_FILENAME (l->l_name), lazy ? " (lazy)" : "");
190 /* DT_TEXTREL is now in level 2 and might phase out at some time.
191 But we rewrite the DT_FLAGS entry to a DT_TEXTREL entry to make
192 testing easier and therefore it will be available at all time. */
193 if (__glibc_unlikely (l->l_info[DT_TEXTREL] != NULL))
195 /* Bletch. We must make read-only segments writable
196 long enough to relocate them. */
197 const ElfW(Phdr) *ph;
198 for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
199 if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
201 struct textrels *newp;
203 newp = (struct textrels *) alloca (sizeof (*newp));
204 newp->len = (((ph->p_vaddr + ph->p_memsz + GLRO(dl_pagesize) - 1)
205 & ~(GLRO(dl_pagesize) - 1))
206 - (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1)));
207 newp->start = ((ph->p_vaddr & ~(GLRO(dl_pagesize) - 1))
208 + (caddr_t) l->l_addr);
210 if (__mprotect (newp->start, newp->len, PROT_READ|PROT_WRITE) < 0)
212 errstring = N_("cannot make segment writable for relocation");
213 call_error:
214 _dl_signal_error (errno, l->l_name, NULL, errstring);
217 #if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
218 newp->prot = (PF_TO_PROT
219 >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
220 #else
221 newp->prot = 0;
222 if (ph->p_flags & PF_R)
223 newp->prot |= PROT_READ;
224 if (ph->p_flags & PF_W)
225 newp->prot |= PROT_WRITE;
226 if (ph->p_flags & PF_X)
227 newp->prot |= PROT_EXEC;
228 #endif
229 newp->next = textrels;
230 textrels = newp;
235 /* Do the actual relocation of the object's GOT and other data. */
237 /* String table object symbols. */
238 const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
240 /* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */
241 #define RESOLVE_MAP(ref, version, r_type) \
242 (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
243 ? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0) \
244 && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class) \
245 ? (bump_num_cache_relocations (), \
246 (*ref) = l->l_lookup_cache.ret, \
247 l->l_lookup_cache.value) \
248 : ({ lookup_t _lr; \
249 int _tc = elf_machine_type_class (r_type); \
250 l->l_lookup_cache.type_class = _tc; \
251 l->l_lookup_cache.sym = (*ref); \
252 const struct r_found_version *v = NULL; \
253 if ((version) != NULL && (version)->hash != 0) \
254 v = (version); \
255 _lr = _dl_lookup_symbol_x (strtab + (*ref)->st_name, l, (ref), \
256 scope, v, _tc, \
257 DL_LOOKUP_ADD_DEPENDENCY, NULL); \
258 l->l_lookup_cache.ret = (*ref); \
259 l->l_lookup_cache.value = _lr; })) \
260 : l)
262 #include "dynamic-link.h"
264 ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling, skip_ifunc);
266 #ifndef PROF
267 if (__glibc_unlikely (consider_profiling))
269 /* Allocate the array which will contain the already found
270 relocations. If the shared object lacks a PLT (for example
271 if it only contains lead function) the l_info[DT_PLTRELSZ]
272 will be NULL. */
273 if (l->l_info[DT_PLTRELSZ] == NULL)
275 errstring = N_("%s: no PLTREL found in object %s\n");
276 fatal:
277 _dl_fatal_printf (errstring,
278 RTLD_PROGNAME,
279 l->l_name);
282 l->l_reloc_result = calloc (sizeof (l->l_reloc_result[0]),
283 l->l_info[DT_PLTRELSZ]->d_un.d_val);
284 if (l->l_reloc_result == NULL)
286 errstring = N_("\
287 %s: out of memory to store relocation results for %s\n");
288 goto fatal;
291 #endif
294 /* Mark the object so we know this work has been done. */
295 l->l_relocated = 1;
297 /* Undo the segment protection changes. */
298 while (__builtin_expect (textrels != NULL, 0))
300 if (__mprotect (textrels->start, textrels->len, textrels->prot) < 0)
302 errstring = N_("cannot restore segment prot after reloc");
303 goto call_error;
306 #ifdef CLEAR_CACHE
307 CLEAR_CACHE (textrels->start, textrels->start + textrels->len);
308 #endif
310 textrels = textrels->next;
313 /* In case we can protect the data now that the relocations are
314 done, do it. */
315 if (l->l_relro_size != 0)
316 _dl_protect_relro (l);
320 void internal_function
321 _dl_protect_relro (struct link_map *l)
323 ElfW(Addr) start = ((l->l_addr + l->l_relro_addr)
324 & ~(GLRO(dl_pagesize) - 1));
325 ElfW(Addr) end = ((l->l_addr + l->l_relro_addr + l->l_relro_size)
326 & ~(GLRO(dl_pagesize) - 1));
328 if (start != end
329 && __mprotect ((void *) start, end - start, PROT_READ) < 0)
331 static const char errstring[] = N_("\
332 cannot apply additional memory protection after relocation");
333 _dl_signal_error (errno, l->l_name, NULL, errstring);
337 void
338 internal_function __attribute_noinline__
339 _dl_reloc_bad_type (struct link_map *map, unsigned int type, int plt)
341 #define DIGIT(b) _itoa_lower_digits[(b) & 0xf];
343 /* XXX We cannot translate these messages. */
344 static const char msg[2][32
345 #if __ELF_NATIVE_CLASS == 64
347 #endif
348 ] = { "unexpected reloc type 0x",
349 "unexpected PLT reloc type 0x" };
350 char msgbuf[sizeof (msg[0])];
351 char *cp;
353 cp = __stpcpy (msgbuf, msg[plt]);
354 #if __ELF_NATIVE_CLASS == 64
355 if (__builtin_expect(type > 0xff, 0))
357 *cp++ = DIGIT (type >> 28);
358 *cp++ = DIGIT (type >> 24);
359 *cp++ = DIGIT (type >> 20);
360 *cp++ = DIGIT (type >> 16);
361 *cp++ = DIGIT (type >> 12);
362 *cp++ = DIGIT (type >> 8);
364 #endif
365 *cp++ = DIGIT (type >> 4);
366 *cp++ = DIGIT (type);
367 *cp = '\0';
369 _dl_signal_error (0, map->l_name, NULL, msgbuf);