Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 1 | /* Write changed data structures. |
| 2 | Copyright (C) 2000-2010 Red Hat, Inc. |
| 3 | This file is part of Red Hat elfutils. |
| 4 | Written by Ulrich Drepper <drepper@redhat.com>, 2000. |
| 5 | |
| 6 | Red Hat elfutils is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by the |
| 8 | Free Software Foundation; version 2 of the License. |
| 9 | |
| 10 | Red Hat elfutils is distributed in the hope that it will be useful, but |
| 11 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License along |
| 16 | with Red Hat elfutils; if not, write to the Free Software Foundation, |
| 17 | Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. |
| 18 | |
| 19 | In addition, as a special exception, Red Hat, Inc. gives You the |
| 20 | additional right to link the code of Red Hat elfutils with code licensed |
| 21 | under any Open Source Initiative certified open source license |
| 22 | (http://www.opensource.org/licenses/index.php) which requires the |
| 23 | distribution of source code with any binary distribution and to |
| 24 | distribute linked combinations of the two. Non-GPL Code permitted under |
| 25 | this exception must only link to the code of Red Hat elfutils through |
| 26 | those well defined interfaces identified in the file named EXCEPTION |
| 27 | found in the source code files (the "Approved Interfaces"). The files |
| 28 | of Non-GPL Code may instantiate templates or use macros or inline |
| 29 | functions from the Approved Interfaces without causing the resulting |
| 30 | work to be covered by the GNU General Public License. Only Red Hat, |
| 31 | Inc. may make changes or additions to the list of Approved Interfaces. |
| 32 | Red Hat's grant of this exception is conditioned upon your not adding |
| 33 | any new exceptions. If you wish to add a new Approved Interface or |
| 34 | exception, please contact Red Hat. You must obey the GNU General Public |
| 35 | License in all respects for all of the Red Hat elfutils code and other |
| 36 | code used in conjunction with Red Hat elfutils except the Non-GPL Code |
| 37 | covered by this exception. If you modify this file, you may extend this |
| 38 | exception to your version of the file, but you are not obligated to do |
| 39 | so. If you do not wish to provide this exception without modification, |
| 40 | you must delete this exception statement from your version and license |
| 41 | this file solely under the GPL without exception. |
| 42 | |
| 43 | Red Hat elfutils is an included package of the Open Invention Network. |
| 44 | An included package of the Open Invention Network is a package for which |
| 45 | Open Invention Network licensees cross-license their patents. No patent |
| 46 | license is granted, either expressly or impliedly, by designation as an |
| 47 | included package. Should you wish to participate in the Open Invention |
| 48 | Network licensing program, please visit www.openinventionnetwork.com |
| 49 | <http://www.openinventionnetwork.com>. */ |
| 50 | |
| 51 | #ifdef HAVE_CONFIG_H |
| 52 | # include <config.h> |
| 53 | #endif |
| 54 | |
| 55 | #include <assert.h> |
| 56 | #include <errno.h> |
| 57 | #include <libelf.h> |
| 58 | #include <stdbool.h> |
| 59 | #include <stdlib.h> |
| 60 | #include <string.h> |
| 61 | #include <unistd.h> |
| 62 | #include <sys/mman.h> |
| 63 | #include <sys/param.h> |
| 64 | |
| 65 | #include <system.h> |
| 66 | #include "libelfP.h" |
| 67 | |
| 68 | |
| 69 | #ifndef LIBELFBITS |
| 70 | # define LIBELFBITS 32 |
| 71 | #endif |
| 72 | |
| 73 | |
| 74 | static int |
| 75 | compare_sections (const void *a, const void *b) |
| 76 | { |
| 77 | const Elf_Scn **scna = (const Elf_Scn **) a; |
| 78 | const Elf_Scn **scnb = (const Elf_Scn **) b; |
| 79 | |
| 80 | if ((*scna)->shdr.ELFW(e,LIBELFBITS)->sh_offset |
| 81 | < (*scnb)->shdr.ELFW(e,LIBELFBITS)->sh_offset) |
| 82 | return -1; |
| 83 | |
| 84 | if ((*scna)->shdr.ELFW(e,LIBELFBITS)->sh_offset |
| 85 | > (*scnb)->shdr.ELFW(e,LIBELFBITS)->sh_offset) |
| 86 | return 1; |
| 87 | |
| 88 | if ((*scna)->shdr.ELFW(e,LIBELFBITS)->sh_size |
| 89 | < (*scnb)->shdr.ELFW(e,LIBELFBITS)->sh_size) |
| 90 | return -1; |
| 91 | |
| 92 | if ((*scna)->shdr.ELFW(e,LIBELFBITS)->sh_size |
| 93 | > (*scnb)->shdr.ELFW(e,LIBELFBITS)->sh_size) |
| 94 | return 1; |
| 95 | |
| 96 | if ((*scna)->index < (*scnb)->index) |
| 97 | return -1; |
| 98 | |
| 99 | if ((*scna)->index > (*scnb)->index) |
| 100 | return 1; |
| 101 | |
| 102 | return 0; |
| 103 | } |
| 104 | |
| 105 | |
| 106 | /* Insert the sections in the list into the provided array and sort |
| 107 | them according to their start offsets. For sections with equal |
| 108 | start offsets, the size is used; for sections with equal start |
| 109 | offsets and sizes, the section index is used. Sorting by size |
| 110 | ensures that zero-length sections are processed first, which |
| 111 | is what we want since they do not advance our file writing position. */ |
| 112 | static void |
| 113 | sort_sections (Elf_Scn **scns, Elf_ScnList *list) |
| 114 | { |
| 115 | Elf_Scn **scnp = scns; |
| 116 | do |
| 117 | for (size_t cnt = 0; cnt < list->cnt; ++cnt) |
| 118 | *scnp++ = &list->data[cnt]; |
| 119 | while ((list = list->next) != NULL); |
| 120 | |
| 121 | qsort (scns, scnp - scns, sizeof (*scns), compare_sections); |
| 122 | } |
| 123 | |
| 124 | |
| 125 | int |
| 126 | internal_function |
| 127 | __elfw2(LIBELFBITS,updatemmap) (Elf *elf, int change_bo, size_t shnum) |
| 128 | { |
| 129 | bool previous_scn_changed = false; |
| 130 | |
| 131 | /* We need the ELF header several times. */ |
| 132 | ElfW2(LIBELFBITS,Ehdr) *ehdr = elf->state.ELFW(elf,LIBELFBITS).ehdr; |
| 133 | |
| 134 | /* Write out the ELF header. */ |
| 135 | if ((elf->state.ELFW(elf,LIBELFBITS).ehdr_flags | elf->flags) & ELF_F_DIRTY) |
| 136 | { |
| 137 | /* If the type sizes should be different at some time we have to |
| 138 | rewrite this code. */ |
| 139 | assert (sizeof (ElfW2(LIBELFBITS,Ehdr)) |
| 140 | == elf_typesize (LIBELFBITS, ELF_T_EHDR, 1)); |
| 141 | |
| 142 | if (unlikely (change_bo)) |
| 143 | { |
| 144 | /* Today there is only one version of the ELF header. */ |
| 145 | #if EV_NUM != 2 |
| 146 | xfct_t fctp; |
| 147 | fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_EHDR]; |
| 148 | #else |
| 149 | # undef fctp |
| 150 | # define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_EHDR] |
| 151 | #endif |
| 152 | |
| 153 | /* Do the real work. */ |
| 154 | (*fctp) ((char *) elf->map_address + elf->start_offset, ehdr, |
| 155 | sizeof (ElfW2(LIBELFBITS,Ehdr)), 1); |
| 156 | } |
| 157 | else |
| 158 | memcpy (elf->map_address + elf->start_offset, ehdr, |
| 159 | sizeof (ElfW2(LIBELFBITS,Ehdr))); |
| 160 | |
| 161 | elf->state.ELFW(elf,LIBELFBITS).ehdr_flags &= ~ELF_F_DIRTY; |
| 162 | |
| 163 | /* We start writing sections after the ELF header only if there is |
| 164 | no program header. */ |
| 165 | previous_scn_changed = elf->state.ELFW(elf,LIBELFBITS).phdr == NULL; |
| 166 | } |
| 167 | |
| 168 | size_t phnum; |
| 169 | if (unlikely (__elf_getphdrnum_rdlock (elf, &phnum) != 0)) |
| 170 | return -1; |
| 171 | |
| 172 | /* Write out the program header table. */ |
| 173 | if (elf->state.ELFW(elf,LIBELFBITS).phdr != NULL |
| 174 | && ((elf->state.ELFW(elf,LIBELFBITS).phdr_flags | elf->flags) |
| 175 | & ELF_F_DIRTY)) |
| 176 | { |
| 177 | /* If the type sizes should be different at some time we have to |
| 178 | rewrite this code. */ |
| 179 | assert (sizeof (ElfW2(LIBELFBITS,Phdr)) |
| 180 | == elf_typesize (LIBELFBITS, ELF_T_PHDR, 1)); |
| 181 | |
| 182 | /* Maybe the user wants a gap between the ELF header and the program |
| 183 | header. */ |
| 184 | if (ehdr->e_phoff > ehdr->e_ehsize) |
| 185 | memset (elf->map_address + elf->start_offset + ehdr->e_ehsize, |
| 186 | __libelf_fill_byte, ehdr->e_phoff - ehdr->e_ehsize); |
| 187 | |
| 188 | if (unlikely (change_bo)) |
| 189 | { |
| 190 | /* Today there is only one version of the ELF header. */ |
| 191 | #if EV_NUM != 2 |
| 192 | xfct_t fctp; |
| 193 | fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_PHDR]; |
| 194 | #else |
| 195 | # undef fctp |
| 196 | # define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_PHDR] |
| 197 | #endif |
| 198 | |
| 199 | /* Do the real work. */ |
| 200 | (*fctp) (elf->map_address + elf->start_offset + ehdr->e_phoff, |
| 201 | elf->state.ELFW(elf,LIBELFBITS).phdr, |
| 202 | sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum, 1); |
| 203 | } |
| 204 | else |
| 205 | memcpy (elf->map_address + elf->start_offset + ehdr->e_phoff, |
| 206 | elf->state.ELFW(elf,LIBELFBITS).phdr, |
| 207 | sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum); |
| 208 | |
| 209 | elf->state.ELFW(elf,LIBELFBITS).phdr_flags &= ~ELF_F_DIRTY; |
| 210 | |
| 211 | /* We modified the program header. Maybe this created a gap so |
| 212 | we have to write fill bytes, if necessary. */ |
| 213 | previous_scn_changed = true; |
| 214 | } |
| 215 | |
| 216 | /* From now on we have to keep track of the last position to eventually |
| 217 | fill the gaps with the prescribed fill byte. */ |
| 218 | char *last_position = ((char *) elf->map_address + elf->start_offset |
| 219 | + MAX (elf_typesize (LIBELFBITS, ELF_T_EHDR, 1), |
| 220 | ehdr->e_phoff) |
| 221 | + elf_typesize (LIBELFBITS, ELF_T_PHDR, phnum)); |
| 222 | |
| 223 | /* Write all the sections. Well, only those which are modified. */ |
| 224 | if (shnum > 0) |
| 225 | { |
| 226 | Elf_ScnList *list = &elf->state.ELFW(elf,LIBELFBITS).scns; |
| 227 | Elf_Scn **scns = (Elf_Scn **) alloca (shnum * sizeof (Elf_Scn *)); |
| 228 | char *const shdr_start = ((char *) elf->map_address + elf->start_offset |
| 229 | + ehdr->e_shoff); |
| 230 | char *const shdr_end = shdr_start + ehdr->e_shnum * ehdr->e_shentsize; |
| 231 | |
| 232 | #if EV_NUM != 2 |
| 233 | xfct_t shdr_fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_SHDR]; |
| 234 | #else |
| 235 | # undef shdr_fctp |
| 236 | # define shdr_fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_SHDR] |
| 237 | #endif |
| 238 | #define shdr_dest ((ElfW2(LIBELFBITS,Shdr) *) shdr_start) |
| 239 | |
| 240 | /* Get all sections into the array and sort them. */ |
| 241 | sort_sections (scns, list); |
| 242 | |
| 243 | /* We possibly have to copy the section header data because moving |
| 244 | the sections might overwrite the data. */ |
| 245 | for (size_t cnt = 0; cnt < shnum; ++cnt) |
| 246 | { |
| 247 | Elf_Scn *scn = scns[cnt]; |
| 248 | |
| 249 | if (!elf->state.ELFW(elf,LIBELFBITS).shdr_malloced |
| 250 | && (scn->shdr_flags & ELF_F_MALLOCED) == 0 |
| 251 | && scn->shdr.ELFW(e,LIBELFBITS) != &shdr_dest[scn->index]) |
| 252 | { |
| 253 | assert ((char *) elf->map_address + elf->start_offset |
| 254 | < (char *) scn->shdr.ELFW(e,LIBELFBITS)); |
| 255 | assert ((char *) scn->shdr.ELFW(e,LIBELFBITS) |
| 256 | < ((char *) elf->map_address + elf->start_offset |
| 257 | + elf->maximum_size)); |
| 258 | |
| 259 | void *p = alloca (sizeof (ElfW2(LIBELFBITS,Shdr))); |
| 260 | scn->shdr.ELFW(e,LIBELFBITS) |
| 261 | = memcpy (p, scn->shdr.ELFW(e,LIBELFBITS), |
| 262 | sizeof (ElfW2(LIBELFBITS,Shdr))); |
| 263 | } |
| 264 | |
| 265 | /* If the file is mmaped and the original position of the |
| 266 | section in the file is lower than the new position we |
| 267 | need to save the section content since otherwise it is |
| 268 | overwritten before it can be copied. If there are |
| 269 | multiple data segments in the list only the first can be |
| 270 | from the file. */ |
| 271 | if (((char *) elf->map_address + elf->start_offset |
| 272 | <= (char *) scn->data_list.data.d.d_buf) |
| 273 | && ((char *) scn->data_list.data.d.d_buf |
| 274 | < ((char *) elf->map_address + elf->start_offset |
| 275 | + elf->maximum_size)) |
| 276 | && (((char *) elf->map_address + elf->start_offset |
| 277 | + scn->shdr.ELFW(e,LIBELFBITS)->sh_offset) |
| 278 | > (char *) scn->data_list.data.d.d_buf)) |
| 279 | { |
| 280 | void *p = malloc (scn->data_list.data.d.d_size); |
| 281 | if (p == NULL) |
| 282 | { |
| 283 | __libelf_seterrno (ELF_E_NOMEM); |
| 284 | return -1; |
| 285 | } |
| 286 | scn->data_list.data.d.d_buf = scn->data_base |
| 287 | = memcpy (p, scn->data_list.data.d.d_buf, |
| 288 | scn->data_list.data.d.d_size); |
| 289 | } |
| 290 | } |
| 291 | |
| 292 | /* Iterate over all the section in the order in which they |
| 293 | appear in the output file. */ |
| 294 | for (size_t cnt = 0; cnt < shnum; ++cnt) |
| 295 | { |
| 296 | Elf_Scn *scn = scns[cnt]; |
| 297 | if (scn->index == 0) |
| 298 | { |
| 299 | /* The dummy section header entry. It should not be |
| 300 | possible to mark this "section" as dirty. */ |
| 301 | assert ((scn->flags & ELF_F_DIRTY) == 0); |
| 302 | continue; |
| 303 | } |
| 304 | |
| 305 | ElfW2(LIBELFBITS,Shdr) *shdr = scn->shdr.ELFW(e,LIBELFBITS); |
| 306 | if (shdr->sh_type == SHT_NOBITS) |
| 307 | goto next; |
| 308 | |
| 309 | char *scn_start = ((char *) elf->map_address |
| 310 | + elf->start_offset + shdr->sh_offset); |
| 311 | Elf_Data_List *dl = &scn->data_list; |
| 312 | bool scn_changed = false; |
| 313 | |
| 314 | void fill_mmap (size_t offset) |
| 315 | { |
| 316 | size_t written = 0; |
| 317 | |
| 318 | if (last_position < shdr_start) |
| 319 | { |
| 320 | written = MIN (scn_start + offset - last_position, |
| 321 | shdr_start - last_position); |
| 322 | |
| 323 | memset (last_position, __libelf_fill_byte, written); |
| 324 | } |
| 325 | |
| 326 | if (last_position + written != scn_start + offset |
| 327 | && shdr_end < scn_start + offset) |
| 328 | { |
| 329 | char *fill_start = MAX (shdr_end, scn_start); |
| 330 | memset (fill_start, __libelf_fill_byte, |
| 331 | scn_start + offset - fill_start); |
| 332 | } |
| 333 | } |
| 334 | |
| 335 | if (scn->data_list_rear != NULL) |
| 336 | do |
| 337 | { |
| 338 | assert (dl->data.d.d_off >= 0); |
| 339 | assert ((GElf_Off) dl->data.d.d_off <= shdr->sh_size); |
| 340 | assert (dl->data.d.d_size <= (shdr->sh_size |
| 341 | - (GElf_Off) dl->data.d.d_off)); |
| 342 | |
| 343 | /* If there is a gap, fill it. */ |
| 344 | if (scn_start + dl->data.d.d_off > last_position |
| 345 | && (dl->data.d.d_off == 0 |
| 346 | || ((scn->flags | dl->flags | elf->flags) |
| 347 | & ELF_F_DIRTY) != 0)) |
| 348 | { |
| 349 | fill_mmap (dl->data.d.d_off); |
| 350 | last_position = scn_start + dl->data.d.d_off; |
| 351 | } |
| 352 | |
| 353 | if ((scn->flags | dl->flags | elf->flags) & ELF_F_DIRTY) |
| 354 | { |
| 355 | /* Let it go backward if the sections use a bogus |
| 356 | layout with overlaps. We'll overwrite the stupid |
| 357 | user's section data with the latest one, rather than |
| 358 | crashing. */ |
| 359 | |
| 360 | last_position = scn_start + dl->data.d.d_off; |
| 361 | |
| 362 | if (unlikely (change_bo)) |
| 363 | { |
| 364 | #if EV_NUM != 2 |
| 365 | xfct_t fctp; |
| 366 | fctp = __elf_xfctstom[__libelf_version - 1][dl->data.d.d_version - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][dl->data.d.d_type]; |
| 367 | #else |
| 368 | # undef fctp |
| 369 | # define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][dl->data.d.d_type] |
| 370 | #endif |
| 371 | |
| 372 | /* Do the real work. */ |
| 373 | (*fctp) (last_position, dl->data.d.d_buf, |
| 374 | dl->data.d.d_size, 1); |
| 375 | |
| 376 | last_position += dl->data.d.d_size; |
| 377 | } |
| 378 | else |
| 379 | last_position = mempcpy (last_position, |
| 380 | dl->data.d.d_buf, |
| 381 | dl->data.d.d_size); |
| 382 | |
| 383 | scn_changed = true; |
| 384 | } |
| 385 | else |
| 386 | last_position += dl->data.d.d_size; |
| 387 | |
| 388 | assert (scn_start + dl->data.d.d_off + dl->data.d.d_size |
| 389 | == last_position); |
| 390 | |
| 391 | dl->flags &= ~ELF_F_DIRTY; |
| 392 | |
| 393 | dl = dl->next; |
| 394 | } |
| 395 | while (dl != NULL); |
| 396 | else |
| 397 | { |
| 398 | /* If the previous section (or the ELF/program |
| 399 | header) changed we might have to fill the gap. */ |
| 400 | if (scn_start > last_position && previous_scn_changed) |
| 401 | fill_mmap (0); |
| 402 | |
| 403 | /* We have to trust the existing section header information. */ |
| 404 | last_position = scn_start + shdr->sh_size; |
| 405 | } |
| 406 | |
| 407 | |
| 408 | previous_scn_changed = scn_changed; |
| 409 | next: |
| 410 | scn->flags &= ~ELF_F_DIRTY; |
| 411 | } |
| 412 | |
| 413 | /* Fill the gap between last section and section header table if |
| 414 | necessary. */ |
| 415 | if ((elf->flags & ELF_F_DIRTY) |
| 416 | && last_position < ((char *) elf->map_address + elf->start_offset |
| 417 | + ehdr->e_shoff)) |
| 418 | memset (last_position, __libelf_fill_byte, |
| 419 | (char *) elf->map_address + elf->start_offset + ehdr->e_shoff |
| 420 | - last_position); |
| 421 | |
| 422 | /* Write the section header table entry if necessary. */ |
| 423 | for (size_t cnt = 0; cnt < shnum; ++cnt) |
| 424 | { |
| 425 | Elf_Scn *scn = scns[cnt]; |
| 426 | |
| 427 | if ((scn->shdr_flags | elf->flags) & ELF_F_DIRTY) |
| 428 | { |
| 429 | if (unlikely (change_bo)) |
| 430 | (*shdr_fctp) (&shdr_dest[scn->index], |
| 431 | scn->shdr.ELFW(e,LIBELFBITS), |
| 432 | sizeof (ElfW2(LIBELFBITS,Shdr)), 1); |
| 433 | else |
| 434 | memcpy (&shdr_dest[scn->index], |
| 435 | scn->shdr.ELFW(e,LIBELFBITS), |
| 436 | sizeof (ElfW2(LIBELFBITS,Shdr))); |
| 437 | |
| 438 | /* If we previously made a copy of the section header |
| 439 | entry we now have to adjust the pointer again so |
| 440 | point to new place in the mapping. */ |
| 441 | if (!elf->state.ELFW(elf,LIBELFBITS).shdr_malloced |
| 442 | && (scn->shdr_flags & ELF_F_MALLOCED) == 0) |
| 443 | scn->shdr.ELFW(e,LIBELFBITS) = &shdr_dest[scn->index]; |
| 444 | |
| 445 | scn->shdr_flags &= ~ELF_F_DIRTY; |
| 446 | } |
| 447 | } |
| 448 | } |
| 449 | |
| 450 | /* That was the last part. Clear the overall flag. */ |
| 451 | elf->flags &= ~ELF_F_DIRTY; |
| 452 | |
| 453 | /* Make sure the content hits the disk. */ |
| 454 | char *msync_start = ((char *) elf->map_address |
| 455 | + (elf->start_offset & ~(sysconf (_SC_PAGESIZE) - 1))); |
| 456 | char *msync_end = ((char *) elf->map_address |
| 457 | + elf->start_offset + ehdr->e_shoff |
| 458 | + ehdr->e_shentsize * shnum); |
| 459 | (void) msync (msync_start, msync_end - msync_start, MS_SYNC); |
| 460 | |
| 461 | return 0; |
| 462 | } |
| 463 | |
| 464 | |
| 465 | /* Size of the buffer we use to generate the blocks of fill bytes. */ |
| 466 | #define FILLBUFSIZE 4096 |
| 467 | |
| 468 | /* If we have to convert the section buffer contents we have to use |
| 469 | temporary buffer. Only buffers up to MAX_TMPBUF bytes are allocated |
| 470 | on the stack. */ |
| 471 | #define MAX_TMPBUF 32768 |
| 472 | |
| 473 | |
| 474 | /* Helper function to write out fill bytes. */ |
| 475 | static int |
| 476 | fill (int fd, off_t pos, size_t len, char *fillbuf, size_t *filledp) |
| 477 | { |
| 478 | size_t filled = *filledp; |
| 479 | size_t fill_len = MIN (len, FILLBUFSIZE); |
| 480 | |
| 481 | if (unlikely (fill_len > filled) && filled < FILLBUFSIZE) |
| 482 | { |
| 483 | /* Initialize a few more bytes. */ |
| 484 | memset (fillbuf + filled, __libelf_fill_byte, fill_len - filled); |
| 485 | *filledp = filled = fill_len; |
| 486 | } |
| 487 | |
| 488 | do |
| 489 | { |
| 490 | /* This many bytes we want to write in this round. */ |
| 491 | size_t n = MIN (filled, len); |
| 492 | |
| 493 | if (unlikely ((size_t) pwrite_retry (fd, fillbuf, n, pos) != n)) |
| 494 | { |
| 495 | __libelf_seterrno (ELF_E_WRITE_ERROR); |
| 496 | return 1; |
| 497 | } |
| 498 | |
| 499 | pos += n; |
| 500 | len -= n; |
| 501 | } |
| 502 | while (len > 0); |
| 503 | |
| 504 | return 0; |
| 505 | } |
| 506 | |
| 507 | |
| 508 | int |
| 509 | internal_function |
| 510 | __elfw2(LIBELFBITS,updatefile) (Elf *elf, int change_bo, size_t shnum) |
| 511 | { |
| 512 | char fillbuf[FILLBUFSIZE]; |
| 513 | size_t filled = 0; |
| 514 | bool previous_scn_changed = false; |
| 515 | |
| 516 | /* We need the ELF header several times. */ |
| 517 | ElfW2(LIBELFBITS,Ehdr) *ehdr = elf->state.ELFW(elf,LIBELFBITS).ehdr; |
| 518 | |
| 519 | /* Write out the ELF header. */ |
| 520 | if ((elf->state.ELFW(elf,LIBELFBITS).ehdr_flags | elf->flags) & ELF_F_DIRTY) |
| 521 | { |
| 522 | ElfW2(LIBELFBITS,Ehdr) tmp_ehdr; |
| 523 | ElfW2(LIBELFBITS,Ehdr) *out_ehdr = ehdr; |
| 524 | |
| 525 | /* If the type sizes should be different at some time we have to |
| 526 | rewrite this code. */ |
| 527 | assert (sizeof (ElfW2(LIBELFBITS,Ehdr)) |
| 528 | == elf_typesize (LIBELFBITS, ELF_T_EHDR, 1)); |
| 529 | |
| 530 | if (unlikely (change_bo)) |
| 531 | { |
| 532 | /* Today there is only one version of the ELF header. */ |
| 533 | #if EV_NUM != 2 |
| 534 | xfct_t fctp; |
| 535 | fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_EHDR]; |
| 536 | #else |
| 537 | # undef fctp |
| 538 | # define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_EHDR] |
| 539 | #endif |
| 540 | |
| 541 | /* Write the converted ELF header in a temporary buffer. */ |
| 542 | (*fctp) (&tmp_ehdr, ehdr, sizeof (ElfW2(LIBELFBITS,Ehdr)), 1); |
| 543 | |
| 544 | /* This is the buffer we want to write. */ |
| 545 | out_ehdr = &tmp_ehdr; |
| 546 | } |
| 547 | |
| 548 | /* Write out the ELF header. */ |
| 549 | if (unlikely (pwrite_retry (elf->fildes, out_ehdr, |
| 550 | sizeof (ElfW2(LIBELFBITS,Ehdr)), 0) |
| 551 | != sizeof (ElfW2(LIBELFBITS,Ehdr)))) |
| 552 | { |
| 553 | __libelf_seterrno (ELF_E_WRITE_ERROR); |
| 554 | return 1; |
| 555 | } |
| 556 | |
| 557 | elf->state.ELFW(elf,LIBELFBITS).ehdr_flags &= ~ELF_F_DIRTY; |
| 558 | |
| 559 | /* We start writing sections after the ELF header only if there is |
| 560 | no program header. */ |
| 561 | previous_scn_changed = elf->state.ELFW(elf,LIBELFBITS).phdr == NULL; |
| 562 | } |
| 563 | |
| 564 | /* If the type sizes should be different at some time we have to |
| 565 | rewrite this code. */ |
| 566 | assert (sizeof (ElfW2(LIBELFBITS,Phdr)) |
| 567 | == elf_typesize (LIBELFBITS, ELF_T_PHDR, 1)); |
| 568 | |
| 569 | size_t phnum; |
| 570 | if (unlikely (__elf_getphdrnum_rdlock (elf, &phnum) != 0)) |
| 571 | return -1; |
| 572 | |
| 573 | /* Write out the program header table. */ |
| 574 | if (elf->state.ELFW(elf,LIBELFBITS).phdr != NULL |
| 575 | && ((elf->state.ELFW(elf,LIBELFBITS).phdr_flags | elf->flags) |
| 576 | & ELF_F_DIRTY)) |
| 577 | { |
| 578 | ElfW2(LIBELFBITS,Phdr) *tmp_phdr = NULL; |
| 579 | ElfW2(LIBELFBITS,Phdr) *out_phdr = elf->state.ELFW(elf,LIBELFBITS).phdr; |
| 580 | |
| 581 | /* Maybe the user wants a gap between the ELF header and the program |
| 582 | header. */ |
| 583 | if (ehdr->e_phoff > ehdr->e_ehsize |
| 584 | && unlikely (fill (elf->fildes, ehdr->e_ehsize, |
| 585 | ehdr->e_phoff - ehdr->e_ehsize, fillbuf, &filled) |
| 586 | != 0)) |
| 587 | return 1; |
| 588 | |
| 589 | if (unlikely (change_bo)) |
| 590 | { |
| 591 | /* Today there is only one version of the ELF header. */ |
| 592 | #if EV_NUM != 2 |
| 593 | xfct_t fctp; |
| 594 | fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_PHDR]; |
| 595 | #else |
| 596 | # undef fctp |
| 597 | # define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_PHDR] |
| 598 | #endif |
| 599 | |
| 600 | /* Allocate sufficient memory. */ |
| 601 | tmp_phdr = (ElfW2(LIBELFBITS,Phdr) *) |
| 602 | malloc (sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum); |
| 603 | if (tmp_phdr == NULL) |
| 604 | { |
| 605 | __libelf_seterrno (ELF_E_NOMEM); |
| 606 | return 1; |
| 607 | } |
| 608 | |
| 609 | /* Write the converted ELF header in a temporary buffer. */ |
| 610 | (*fctp) (tmp_phdr, elf->state.ELFW(elf,LIBELFBITS).phdr, |
| 611 | sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum, 1); |
| 612 | |
| 613 | /* This is the buffer we want to write. */ |
| 614 | out_phdr = tmp_phdr; |
| 615 | } |
| 616 | |
| 617 | /* Write out the ELF header. */ |
| 618 | size_t phdr_size = sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum; |
| 619 | if (unlikely ((size_t) pwrite_retry (elf->fildes, out_phdr, |
| 620 | phdr_size, ehdr->e_phoff) |
| 621 | != phdr_size)) |
| 622 | { |
| 623 | __libelf_seterrno (ELF_E_WRITE_ERROR); |
| 624 | return 1; |
| 625 | } |
| 626 | |
| 627 | /* This is a no-op we we have not allocated any memory. */ |
| 628 | free (tmp_phdr); |
| 629 | |
| 630 | elf->state.ELFW(elf,LIBELFBITS).phdr_flags &= ~ELF_F_DIRTY; |
| 631 | |
| 632 | /* We modified the program header. Maybe this created a gap so |
| 633 | we have to write fill bytes, if necessary. */ |
| 634 | previous_scn_changed = true; |
| 635 | } |
| 636 | |
| 637 | /* From now on we have to keep track of the last position to eventually |
| 638 | fill the gaps with the prescribed fill byte. */ |
| 639 | off_t last_offset; |
| 640 | if (elf->state.ELFW(elf,LIBELFBITS).phdr == NULL) |
| 641 | last_offset = elf_typesize (LIBELFBITS, ELF_T_EHDR, 1); |
| 642 | else |
| 643 | last_offset = (ehdr->e_phoff + sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum); |
| 644 | |
| 645 | /* Write all the sections. Well, only those which are modified. */ |
| 646 | if (shnum > 0) |
| 647 | { |
| 648 | off_t shdr_offset = elf->start_offset + ehdr->e_shoff; |
| 649 | #if EV_NUM != 2 |
| 650 | xfct_t shdr_fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_SHDR]; |
| 651 | #else |
| 652 | # undef shdr_fctp |
| 653 | # define shdr_fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_SHDR] |
| 654 | #endif |
| 655 | |
| 656 | ElfW2(LIBELFBITS,Shdr) *shdr_data; |
| 657 | if (change_bo || elf->state.ELFW(elf,LIBELFBITS).shdr == NULL) |
| 658 | shdr_data = (ElfW2(LIBELFBITS,Shdr) *) |
| 659 | alloca (shnum * sizeof (ElfW2(LIBELFBITS,Shdr))); |
| 660 | else |
| 661 | shdr_data = elf->state.ELFW(elf,LIBELFBITS).shdr; |
| 662 | int shdr_flags = elf->flags; |
| 663 | |
| 664 | /* Get all sections into the array and sort them. */ |
| 665 | Elf_ScnList *list = &elf->state.ELFW(elf,LIBELFBITS).scns; |
| 666 | Elf_Scn **scns = (Elf_Scn **) alloca (shnum * sizeof (Elf_Scn *)); |
| 667 | sort_sections (scns, list); |
| 668 | |
| 669 | for (size_t cnt = 0; cnt < shnum; ++cnt) |
| 670 | { |
| 671 | Elf_Scn *scn = scns[cnt]; |
| 672 | if (scn->index == 0) |
| 673 | { |
| 674 | /* The dummy section header entry. It should not be |
| 675 | possible to mark this "section" as dirty. */ |
| 676 | assert ((scn->flags & ELF_F_DIRTY) == 0); |
| 677 | goto next; |
| 678 | } |
| 679 | |
| 680 | ElfW2(LIBELFBITS,Shdr) *shdr = scn->shdr.ELFW(e,LIBELFBITS); |
| 681 | if (shdr->sh_type == SHT_NOBITS) |
| 682 | goto next; |
| 683 | |
| 684 | off_t scn_start = elf->start_offset + shdr->sh_offset; |
| 685 | Elf_Data_List *dl = &scn->data_list; |
| 686 | bool scn_changed = false; |
| 687 | |
| 688 | if (scn->data_list_rear != NULL) |
| 689 | do |
| 690 | { |
| 691 | /* If there is a gap, fill it. */ |
| 692 | if (scn_start + dl->data.d.d_off > last_offset |
| 693 | && ((previous_scn_changed && dl->data.d.d_off == 0) |
| 694 | || ((scn->flags | dl->flags | elf->flags) |
| 695 | & ELF_F_DIRTY) != 0)) |
| 696 | { |
| 697 | if (unlikely (fill (elf->fildes, last_offset, |
| 698 | (scn_start + dl->data.d.d_off) |
| 699 | - last_offset, fillbuf, |
| 700 | &filled) != 0)) |
| 701 | return 1; |
| 702 | } |
| 703 | |
| 704 | if ((scn->flags | dl->flags | elf->flags) & ELF_F_DIRTY) |
| 705 | { |
| 706 | char tmpbuf[MAX_TMPBUF]; |
| 707 | void *buf = dl->data.d.d_buf; |
| 708 | |
| 709 | /* Let it go backward if the sections use a bogus |
| 710 | layout with overlaps. We'll overwrite the stupid |
| 711 | user's section data with the latest one, rather than |
| 712 | crashing. */ |
| 713 | |
| 714 | last_offset = scn_start + dl->data.d.d_off; |
| 715 | |
| 716 | if (unlikely (change_bo)) |
| 717 | { |
| 718 | #if EV_NUM != 2 |
| 719 | xfct_t fctp; |
| 720 | fctp = __elf_xfctstom[__libelf_version - 1][dl->data.d.d_version - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][dl->data.d.d_type]; |
| 721 | #else |
| 722 | # undef fctp |
| 723 | # define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][dl->data.d.d_type] |
| 724 | #endif |
| 725 | |
| 726 | buf = tmpbuf; |
| 727 | if (dl->data.d.d_size > MAX_TMPBUF) |
| 728 | { |
| 729 | buf = malloc (dl->data.d.d_size); |
| 730 | if (buf == NULL) |
| 731 | { |
| 732 | __libelf_seterrno (ELF_E_NOMEM); |
| 733 | return 1; |
| 734 | } |
| 735 | } |
| 736 | |
| 737 | /* Do the real work. */ |
| 738 | (*fctp) (buf, dl->data.d.d_buf, dl->data.d.d_size, 1); |
| 739 | } |
| 740 | |
| 741 | ssize_t n = pwrite_retry (elf->fildes, buf, |
| 742 | dl->data.d.d_size, |
| 743 | last_offset); |
| 744 | if (unlikely ((size_t) n != dl->data.d.d_size)) |
| 745 | { |
| 746 | if (buf != dl->data.d.d_buf && buf != tmpbuf) |
| 747 | free (buf); |
| 748 | |
| 749 | __libelf_seterrno (ELF_E_WRITE_ERROR); |
| 750 | return 1; |
| 751 | } |
| 752 | |
| 753 | if (buf != dl->data.d.d_buf && buf != tmpbuf) |
| 754 | free (buf); |
| 755 | |
| 756 | scn_changed = true; |
| 757 | } |
| 758 | |
| 759 | last_offset += dl->data.d.d_size; |
| 760 | |
| 761 | dl->flags &= ~ELF_F_DIRTY; |
| 762 | |
| 763 | dl = dl->next; |
| 764 | } |
| 765 | while (dl != NULL); |
| 766 | else |
| 767 | { |
| 768 | /* If the previous section (or the ELF/program |
| 769 | header) changed we might have to fill the gap. */ |
| 770 | if (scn_start > last_offset && previous_scn_changed) |
| 771 | { |
| 772 | if (unlikely (fill (elf->fildes, last_offset, |
| 773 | scn_start - last_offset, fillbuf, |
| 774 | &filled) != 0)) |
| 775 | return 1; |
| 776 | } |
| 777 | |
| 778 | last_offset = scn_start + shdr->sh_size; |
| 779 | } |
| 780 | |
| 781 | previous_scn_changed = scn_changed; |
| 782 | next: |
| 783 | /* Collect the section header table information. */ |
| 784 | if (unlikely (change_bo)) |
| 785 | (*shdr_fctp) (&shdr_data[scn->index], |
| 786 | scn->shdr.ELFW(e,LIBELFBITS), |
| 787 | sizeof (ElfW2(LIBELFBITS,Shdr)), 1); |
| 788 | else if (elf->state.ELFW(elf,LIBELFBITS).shdr == NULL) |
| 789 | memcpy (&shdr_data[scn->index], scn->shdr.ELFW(e,LIBELFBITS), |
| 790 | sizeof (ElfW2(LIBELFBITS,Shdr))); |
| 791 | |
| 792 | shdr_flags |= scn->shdr_flags; |
| 793 | scn->shdr_flags &= ~ELF_F_DIRTY; |
| 794 | } |
| 795 | |
| 796 | /* Fill the gap between last section and section header table if |
| 797 | necessary. */ |
| 798 | if ((elf->flags & ELF_F_DIRTY) && last_offset < shdr_offset |
| 799 | && unlikely (fill (elf->fildes, last_offset, |
| 800 | shdr_offset - last_offset, |
| 801 | fillbuf, &filled) != 0)) |
| 802 | return 1; |
| 803 | |
| 804 | /* Write out the section header table. */ |
| 805 | if (shdr_flags & ELF_F_DIRTY |
| 806 | && unlikely ((size_t) pwrite_retry (elf->fildes, shdr_data, |
| 807 | sizeof (ElfW2(LIBELFBITS,Shdr)) |
| 808 | * shnum, shdr_offset) |
| 809 | != sizeof (ElfW2(LIBELFBITS,Shdr)) * shnum)) |
| 810 | { |
| 811 | __libelf_seterrno (ELF_E_WRITE_ERROR); |
| 812 | return 1; |
| 813 | } |
| 814 | } |
| 815 | |
| 816 | /* That was the last part. Clear the overall flag. */ |
| 817 | elf->flags &= ~ELF_F_DIRTY; |
| 818 | |
| 819 | return 0; |
| 820 | } |