| 1 | /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992 |
| 2 | Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GNU Emacs. |
| 5 | |
| 6 | GNU Emacs is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2, or (at your option) |
| 9 | any later version. |
| 10 | |
| 11 | GNU Emacs is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with GNU Emacs; see the file COPYING. If not, write to |
| 18 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 19 | Boston, MA 02111-1307, USA. |
| 20 | |
| 21 | In other words, you are welcome to use, share and improve this program. |
| 22 | You are forbidden to forbid anyone else to use, share and improve |
| 23 | what you give them. Help stamp out software-hoarding! */ |
| 24 | |
| 25 | |
| 26 | /* |
| 27 | * unexec.c - Convert a running program into an a.out file. |
| 28 | * |
| 29 | * Author: Spencer W. Thomas |
| 30 | * Computer Science Dept. |
| 31 | * University of Utah |
| 32 | * Date: Tue Mar 2 1982 |
| 33 | * Modified heavily since then. |
| 34 | * |
| 35 | * Synopsis: |
| 36 | * unexec (new_name, a_name, data_start, bss_start, entry_address) |
| 37 | * char *new_name, *a_name; |
| 38 | * unsigned data_start, bss_start, entry_address; |
| 39 | * |
| 40 | * Takes a snapshot of the program and makes an a.out format file in the |
| 41 | * file named by the string argument new_name. |
| 42 | * If a_name is non-NULL, the symbol table will be taken from the given file. |
| 43 | * On some machines, an existing a_name file is required. |
| 44 | * |
| 45 | * The boundaries within the a.out file may be adjusted with the data_start |
| 46 | * and bss_start arguments. Either or both may be given as 0 for defaults. |
| 47 | * |
| 48 | * Data_start gives the boundary between the text segment and the data |
| 49 | * segment of the program. The text segment can contain shared, read-only |
| 50 | * program code and literal data, while the data segment is always unshared |
| 51 | * and unprotected. Data_start gives the lowest unprotected address. |
| 52 | * The value you specify may be rounded down to a suitable boundary |
| 53 | * as required by the machine you are using. |
| 54 | * |
| 55 | * Specifying zero for data_start means the boundary between text and data |
| 56 | * should not be the same as when the program was loaded. |
| 57 | * If NO_REMAP is defined, the argument data_start is ignored and the |
| 58 | * segment boundaries are never changed. |
| 59 | * |
| 60 | * Bss_start indicates how much of the data segment is to be saved in the |
| 61 | * a.out file and restored when the program is executed. It gives the lowest |
| 62 | * unsaved address, and is rounded up to a page boundary. The default when 0 |
| 63 | * is given assumes that the entire data segment is to be stored, including |
| 64 | * the previous data and bss as well as any additional storage allocated with |
| 65 | * break (2). |
| 66 | * |
| 67 | * The new file is set up to start at entry_address. |
| 68 | * |
| 69 | * If you make improvements I'd like to get them too. |
| 70 | * harpo!utah-cs!thomas, thomas@Utah-20 |
| 71 | * |
| 72 | */ |
| 73 | |
| 74 | /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co. |
| 75 | * ELF support added. |
| 76 | * |
| 77 | * Basic theory: the data space of the running process needs to be |
| 78 | * dumped to the output file. Normally we would just enlarge the size |
| 79 | * of .data, scooting everything down. But we can't do that in ELF, |
| 80 | * because there is often something between the .data space and the |
| 81 | * .bss space. |
| 82 | * |
| 83 | * In the temacs dump below, notice that the Global Offset Table |
| 84 | * (.got) and the Dynamic link data (.dynamic) come between .data1 and |
| 85 | * .bss. It does not work to overlap .data with these fields. |
| 86 | * |
| 87 | * The solution is to create a new .data segment. This segment is |
| 88 | * filled with data from the current process. Since the contents of |
| 89 | * various sections refer to sections by index, the new .data segment |
| 90 | * is made the last in the table to avoid changing any existing index. |
| 91 | |
| 92 | * This is an example of how the section headers are changed. "Addr" |
| 93 | * is a process virtual address. "Offset" is a file offset. |
| 94 | |
| 95 | raid:/nfs/raid/src/dist-18.56/src> dump -h temacs |
| 96 | |
| 97 | temacs: |
| 98 | |
| 99 | **** SECTION HEADER TABLE **** |
| 100 | [No] Type Flags Addr Offset Size Name |
| 101 | Link Info Adralgn Entsize |
| 102 | |
| 103 | [1] 1 2 0x80480d4 0xd4 0x13 .interp |
| 104 | 0 0 0x1 0 |
| 105 | |
| 106 | [2] 5 2 0x80480e8 0xe8 0x388 .hash |
| 107 | 3 0 0x4 0x4 |
| 108 | |
| 109 | [3] 11 2 0x8048470 0x470 0x7f0 .dynsym |
| 110 | 4 1 0x4 0x10 |
| 111 | |
| 112 | [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr |
| 113 | 0 0 0x1 0 |
| 114 | |
| 115 | [5] 9 2 0x8049010 0x1010 0x338 .rel.plt |
| 116 | 3 7 0x4 0x8 |
| 117 | |
| 118 | [6] 1 6 0x8049348 0x1348 0x3 .init |
| 119 | 0 0 0x4 0 |
| 120 | |
| 121 | [7] 1 6 0x804934c 0x134c 0x680 .plt |
| 122 | 0 0 0x4 0x4 |
| 123 | |
| 124 | [8] 1 6 0x80499cc 0x19cc 0x3c56f .text |
| 125 | 0 0 0x4 0 |
| 126 | |
| 127 | [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini |
| 128 | 0 0 0x4 0 |
| 129 | |
| 130 | [10] 1 2 0x8085f40 0x3df40 0x69c .rodata |
| 131 | 0 0 0x4 0 |
| 132 | |
| 133 | [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1 |
| 134 | 0 0 0x4 0 |
| 135 | |
| 136 | [12] 1 3 0x8088330 0x3f330 0x20afc .data |
| 137 | 0 0 0x4 0 |
| 138 | |
| 139 | [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1 |
| 140 | 0 0 0x4 0 |
| 141 | |
| 142 | [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got |
| 143 | 0 0 0x4 0x4 |
| 144 | |
| 145 | [15] 6 3 0x80a9874 0x60874 0x80 .dynamic |
| 146 | 4 0 0x4 0x8 |
| 147 | |
| 148 | [16] 8 3 0x80a98f4 0x608f4 0x449c .bss |
| 149 | 0 0 0x4 0 |
| 150 | |
| 151 | [17] 2 0 0 0x608f4 0x9b90 .symtab |
| 152 | 18 371 0x4 0x10 |
| 153 | |
| 154 | [18] 3 0 0 0x6a484 0x8526 .strtab |
| 155 | 0 0 0x1 0 |
| 156 | |
| 157 | [19] 3 0 0 0x729aa 0x93 .shstrtab |
| 158 | 0 0 0x1 0 |
| 159 | |
| 160 | [20] 1 0 0 0x72a3d 0x68b7 .comment |
| 161 | 0 0 0x1 0 |
| 162 | |
| 163 | raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs |
| 164 | |
| 165 | xemacs: |
| 166 | |
| 167 | **** SECTION HEADER TABLE **** |
| 168 | [No] Type Flags Addr Offset Size Name |
| 169 | Link Info Adralgn Entsize |
| 170 | |
| 171 | [1] 1 2 0x80480d4 0xd4 0x13 .interp |
| 172 | 0 0 0x1 0 |
| 173 | |
| 174 | [2] 5 2 0x80480e8 0xe8 0x388 .hash |
| 175 | 3 0 0x4 0x4 |
| 176 | |
| 177 | [3] 11 2 0x8048470 0x470 0x7f0 .dynsym |
| 178 | 4 1 0x4 0x10 |
| 179 | |
| 180 | [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr |
| 181 | 0 0 0x1 0 |
| 182 | |
| 183 | [5] 9 2 0x8049010 0x1010 0x338 .rel.plt |
| 184 | 3 7 0x4 0x8 |
| 185 | |
| 186 | [6] 1 6 0x8049348 0x1348 0x3 .init |
| 187 | 0 0 0x4 0 |
| 188 | |
| 189 | [7] 1 6 0x804934c 0x134c 0x680 .plt |
| 190 | 0 0 0x4 0x4 |
| 191 | |
| 192 | [8] 1 6 0x80499cc 0x19cc 0x3c56f .text |
| 193 | 0 0 0x4 0 |
| 194 | |
| 195 | [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini |
| 196 | 0 0 0x4 0 |
| 197 | |
| 198 | [10] 1 2 0x8085f40 0x3df40 0x69c .rodata |
| 199 | 0 0 0x4 0 |
| 200 | |
| 201 | [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1 |
| 202 | 0 0 0x4 0 |
| 203 | |
| 204 | [12] 1 3 0x8088330 0x3f330 0x20afc .data |
| 205 | 0 0 0x4 0 |
| 206 | |
| 207 | [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1 |
| 208 | 0 0 0x4 0 |
| 209 | |
| 210 | [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got |
| 211 | 0 0 0x4 0x4 |
| 212 | |
| 213 | [15] 6 3 0x80a9874 0x60874 0x80 .dynamic |
| 214 | 4 0 0x4 0x8 |
| 215 | |
| 216 | [16] 8 3 0x80c6800 0x7d800 0 .bss |
| 217 | 0 0 0x4 0 |
| 218 | |
| 219 | [17] 2 0 0 0x7d800 0x9b90 .symtab |
| 220 | 18 371 0x4 0x10 |
| 221 | |
| 222 | [18] 3 0 0 0x87390 0x8526 .strtab |
| 223 | 0 0 0x1 0 |
| 224 | |
| 225 | [19] 3 0 0 0x8f8b6 0x93 .shstrtab |
| 226 | 0 0 0x1 0 |
| 227 | |
| 228 | [20] 1 0 0 0x8f949 0x68b7 .comment |
| 229 | 0 0 0x1 0 |
| 230 | |
| 231 | [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data |
| 232 | 0 0 0x4 0 |
| 233 | |
| 234 | * This is an example of how the file header is changed. "Shoff" is |
| 235 | * the section header offset within the file. Since that table is |
| 236 | * after the new .data section, it is moved. "Shnum" is the number of |
| 237 | * sections, which we increment. |
| 238 | * |
| 239 | * "Phoff" is the file offset to the program header. "Phentsize" and |
| 240 | * "Shentsz" are the program and section header entries sizes respectively. |
| 241 | * These can be larger than the apparent struct sizes. |
| 242 | |
| 243 | raid:/nfs/raid/src/dist-18.56/src> dump -f temacs |
| 244 | |
| 245 | temacs: |
| 246 | |
| 247 | **** ELF HEADER **** |
| 248 | Class Data Type Machine Version |
| 249 | Entry Phoff Shoff Flags Ehsize |
| 250 | Phentsize Phnum Shentsz Shnum Shstrndx |
| 251 | |
| 252 | 1 1 2 3 1 |
| 253 | 0x80499cc 0x34 0x792f4 0 0x34 |
| 254 | 0x20 5 0x28 21 19 |
| 255 | |
| 256 | raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs |
| 257 | |
| 258 | xemacs: |
| 259 | |
| 260 | **** ELF HEADER **** |
| 261 | Class Data Type Machine Version |
| 262 | Entry Phoff Shoff Flags Ehsize |
| 263 | Phentsize Phnum Shentsz Shnum Shstrndx |
| 264 | |
| 265 | 1 1 2 3 1 |
| 266 | 0x80499cc 0x34 0x96200 0 0x34 |
| 267 | 0x20 5 0x28 22 19 |
| 268 | |
| 269 | * These are the program headers. "Offset" is the file offset to the |
| 270 | * segment. "Vaddr" is the memory load address. "Filesz" is the |
| 271 | * segment size as it appears in the file, and "Memsz" is the size in |
| 272 | * memory. Below, the third segment is the code and the fourth is the |
| 273 | * data: the difference between Filesz and Memsz is .bss |
| 274 | |
| 275 | raid:/nfs/raid/src/dist-18.56/src> dump -o temacs |
| 276 | |
| 277 | temacs: |
| 278 | ***** PROGRAM EXECUTION HEADER ***** |
| 279 | Type Offset Vaddr Paddr |
| 280 | Filesz Memsz Flags Align |
| 281 | |
| 282 | 6 0x34 0x8048034 0 |
| 283 | 0xa0 0xa0 5 0 |
| 284 | |
| 285 | 3 0xd4 0 0 |
| 286 | 0x13 0 4 0 |
| 287 | |
| 288 | 1 0x34 0x8048034 0 |
| 289 | 0x3f2f9 0x3f2f9 5 0x1000 |
| 290 | |
| 291 | 1 0x3f330 0x8088330 0 |
| 292 | 0x215c4 0x25a60 7 0x1000 |
| 293 | |
| 294 | 2 0x60874 0x80a9874 0 |
| 295 | 0x80 0 7 0 |
| 296 | |
| 297 | raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs |
| 298 | |
| 299 | xemacs: |
| 300 | ***** PROGRAM EXECUTION HEADER ***** |
| 301 | Type Offset Vaddr Paddr |
| 302 | Filesz Memsz Flags Align |
| 303 | |
| 304 | 6 0x34 0x8048034 0 |
| 305 | 0xa0 0xa0 5 0 |
| 306 | |
| 307 | 3 0xd4 0 0 |
| 308 | 0x13 0 4 0 |
| 309 | |
| 310 | 1 0x34 0x8048034 0 |
| 311 | 0x3f2f9 0x3f2f9 5 0x1000 |
| 312 | |
| 313 | 1 0x3f330 0x8088330 0 |
| 314 | 0x3e4d0 0x3e4d0 7 0x1000 |
| 315 | |
| 316 | 2 0x60874 0x80a9874 0 |
| 317 | 0x80 0 7 0 |
| 318 | |
| 319 | |
| 320 | */ |
| 321 | \f |
| 322 | /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc. |
| 323 | * |
| 324 | * The above mechanism does not work if the unexeced ELF file is being |
| 325 | * re-layout by other applications (such as `strip'). All the applications |
| 326 | * that re-layout the internal of ELF will layout all sections in ascending |
| 327 | * order of their file offsets. After the re-layout, the data2 section will |
| 328 | * still be the LAST section in the section header vector, but its file offset |
| 329 | * is now being pushed far away down, and causes part of it not to be mapped |
| 330 | * in (ie. not covered by the load segment entry in PHDR vector), therefore |
| 331 | * causes the new binary to fail. |
| 332 | * |
| 333 | * The solution is to modify the unexec algorithm to insert the new data2 |
| 334 | * section header right before the new bss section header, so their file |
| 335 | * offsets will be in the ascending order. Since some of the section's (all |
| 336 | * sections AFTER the bss section) indexes are now changed, we also need to |
| 337 | * modify some fields to make them point to the right sections. This is done |
| 338 | * by macro PATCH_INDEX. All the fields that need to be patched are: |
| 339 | * |
| 340 | * 1. ELF header e_shstrndx field. |
| 341 | * 2. section header sh_link and sh_info field. |
| 342 | * 3. symbol table entry st_shndx field. |
| 343 | * |
| 344 | * The above example now should look like: |
| 345 | |
| 346 | **** SECTION HEADER TABLE **** |
| 347 | [No] Type Flags Addr Offset Size Name |
| 348 | Link Info Adralgn Entsize |
| 349 | |
| 350 | [1] 1 2 0x80480d4 0xd4 0x13 .interp |
| 351 | 0 0 0x1 0 |
| 352 | |
| 353 | [2] 5 2 0x80480e8 0xe8 0x388 .hash |
| 354 | 3 0 0x4 0x4 |
| 355 | |
| 356 | [3] 11 2 0x8048470 0x470 0x7f0 .dynsym |
| 357 | 4 1 0x4 0x10 |
| 358 | |
| 359 | [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr |
| 360 | 0 0 0x1 0 |
| 361 | |
| 362 | [5] 9 2 0x8049010 0x1010 0x338 .rel.plt |
| 363 | 3 7 0x4 0x8 |
| 364 | |
| 365 | [6] 1 6 0x8049348 0x1348 0x3 .init |
| 366 | 0 0 0x4 0 |
| 367 | |
| 368 | [7] 1 6 0x804934c 0x134c 0x680 .plt |
| 369 | 0 0 0x4 0x4 |
| 370 | |
| 371 | [8] 1 6 0x80499cc 0x19cc 0x3c56f .text |
| 372 | 0 0 0x4 0 |
| 373 | |
| 374 | [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini |
| 375 | 0 0 0x4 0 |
| 376 | |
| 377 | [10] 1 2 0x8085f40 0x3df40 0x69c .rodata |
| 378 | 0 0 0x4 0 |
| 379 | |
| 380 | [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1 |
| 381 | 0 0 0x4 0 |
| 382 | |
| 383 | [12] 1 3 0x8088330 0x3f330 0x20afc .data |
| 384 | 0 0 0x4 0 |
| 385 | |
| 386 | [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1 |
| 387 | 0 0 0x4 0 |
| 388 | |
| 389 | [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got |
| 390 | 0 0 0x4 0x4 |
| 391 | |
| 392 | [15] 6 3 0x80a9874 0x60874 0x80 .dynamic |
| 393 | 4 0 0x4 0x8 |
| 394 | |
| 395 | [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data |
| 396 | 0 0 0x4 0 |
| 397 | |
| 398 | [17] 8 3 0x80c6800 0x7d800 0 .bss |
| 399 | 0 0 0x4 0 |
| 400 | |
| 401 | [18] 2 0 0 0x7d800 0x9b90 .symtab |
| 402 | 19 371 0x4 0x10 |
| 403 | |
| 404 | [19] 3 0 0 0x87390 0x8526 .strtab |
| 405 | 0 0 0x1 0 |
| 406 | |
| 407 | [20] 3 0 0 0x8f8b6 0x93 .shstrtab |
| 408 | 0 0 0x1 0 |
| 409 | |
| 410 | [21] 1 0 0 0x8f949 0x68b7 .comment |
| 411 | 0 0 0x1 0 |
| 412 | |
| 413 | */ |
| 414 | \f |
| 415 | #include <sys/types.h> |
| 416 | #include <stdio.h> |
| 417 | #include <sys/stat.h> |
| 418 | #include <memory.h> |
| 419 | #include <string.h> |
| 420 | #include <errno.h> |
| 421 | #include <unistd.h> |
| 422 | #include <fcntl.h> |
| 423 | #include <elf.h> |
| 424 | #include <syms.h> /* for HDRR declaration */ |
| 425 | #include <sys/mman.h> |
| 426 | |
| 427 | #ifndef emacs |
| 428 | #define fatal(a, b, c) fprintf(stderr, a, b, c), exit(1) |
| 429 | #else |
| 430 | extern void fatal(char *, ...); |
| 431 | #endif |
| 432 | |
| 433 | /* Get the address of a particular section or program header entry, |
| 434 | * accounting for the size of the entries. |
| 435 | */ |
| 436 | |
| 437 | #define OLD_SECTION_H(n) \ |
| 438 | (*(Elf32_Shdr *) ((byte *) old_section_h + old_file_h->e_shentsize * (n))) |
| 439 | #define NEW_SECTION_H(n) \ |
| 440 | (*(Elf32_Shdr *) ((byte *) new_section_h + new_file_h->e_shentsize * (n))) |
| 441 | #define OLD_PROGRAM_H(n) \ |
| 442 | (*(Elf32_Phdr *) ((byte *) old_program_h + old_file_h->e_phentsize * (n))) |
| 443 | #define NEW_PROGRAM_H(n) \ |
| 444 | (*(Elf32_Phdr *) ((byte *) new_program_h + new_file_h->e_phentsize * (n))) |
| 445 | |
| 446 | #define PATCH_INDEX(n) \ |
| 447 | do { \ |
| 448 | if ((n) >= old_bss_index) \ |
| 449 | (n)++; } while (0) |
| 450 | typedef unsigned char byte; |
| 451 | |
| 452 | /* Round X up to a multiple of Y. */ |
| 453 | |
| 454 | int |
| 455 | round_up (x, y) |
| 456 | int x, y; |
| 457 | { |
| 458 | int rem = x % y; |
| 459 | if (rem == 0) |
| 460 | return x; |
| 461 | return x - rem + y; |
| 462 | } |
| 463 | |
| 464 | /* Return the index of the section named NAME. |
| 465 | SECTION_NAMES, FILE_NAME and FILE_H give information |
| 466 | about the file we are looking in. |
| 467 | |
| 468 | If we don't find the section NAME, that is a fatal error |
| 469 | if NOERROR is 0; we return -1 if NOERROR is nonzero. */ |
| 470 | |
| 471 | static int |
| 472 | find_section (name, section_names, file_name, old_file_h, old_section_h, noerror) |
| 473 | char *name; |
| 474 | char *section_names; |
| 475 | char *file_name; |
| 476 | Elf32_Ehdr *old_file_h; |
| 477 | Elf32_Shdr *old_section_h; |
| 478 | int noerror; |
| 479 | { |
| 480 | int idx; |
| 481 | |
| 482 | for (idx = 1; idx < old_file_h->e_shnum; idx++) |
| 483 | { |
| 484 | #ifdef DEBUG |
| 485 | fprintf (stderr, "Looking for %s - found %s\n", name, |
| 486 | section_names + OLD_SECTION_H (idx).sh_name); |
| 487 | #endif |
| 488 | if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name, |
| 489 | name)) |
| 490 | break; |
| 491 | } |
| 492 | if (idx == old_file_h->e_shnum) |
| 493 | { |
| 494 | if (noerror) |
| 495 | return -1; |
| 496 | else |
| 497 | fatal ("Can't find .bss in %s.\n", file_name, 0); |
| 498 | } |
| 499 | |
| 500 | return idx; |
| 501 | } |
| 502 | |
| 503 | /* **************************************************************** |
| 504 | * unexec |
| 505 | * |
| 506 | * driving logic. |
| 507 | * |
| 508 | * In ELF, this works by replacing the old .bss section with a new |
| 509 | * .data section, and inserting an empty .bss immediately afterwards. |
| 510 | * |
| 511 | */ |
| 512 | void |
| 513 | unexec (new_name, old_name, data_start, bss_start, entry_address) |
| 514 | char *new_name, *old_name; |
| 515 | unsigned data_start, bss_start, entry_address; |
| 516 | { |
| 517 | extern unsigned int bss_end; |
| 518 | int new_file, old_file, new_file_size; |
| 519 | |
| 520 | /* Pointers to the base of the image of the two files. */ |
| 521 | caddr_t old_base, new_base; |
| 522 | |
| 523 | /* Pointers to the file, program and section headers for the old and new |
| 524 | files. */ |
| 525 | Elf32_Ehdr *old_file_h, *new_file_h; |
| 526 | Elf32_Phdr *old_program_h, *new_program_h; |
| 527 | Elf32_Shdr *old_section_h, *new_section_h; |
| 528 | |
| 529 | /* Point to the section name table in the old file. */ |
| 530 | char *old_section_names; |
| 531 | |
| 532 | Elf32_Addr old_bss_addr, new_bss_addr; |
| 533 | Elf32_Word old_bss_size, new_data2_size; |
| 534 | Elf32_Off new_data2_offset; |
| 535 | Elf32_Addr new_data2_addr; |
| 536 | Elf32_Addr new_offsets_shift; |
| 537 | |
| 538 | int n, nn, old_bss_index, old_data_index, new_data2_index; |
| 539 | int old_mdebug_index; |
| 540 | struct stat stat_buf; |
| 541 | |
| 542 | /* Open the old file & map it into the address space. */ |
| 543 | |
| 544 | old_file = open (old_name, O_RDONLY); |
| 545 | |
| 546 | if (old_file < 0) |
| 547 | fatal ("Can't open %s for reading: errno %d\n", old_name, errno); |
| 548 | |
| 549 | if (fstat (old_file, &stat_buf) == -1) |
| 550 | fatal ("Can't fstat(%s): errno %d\n", old_name, errno); |
| 551 | |
| 552 | old_base = mmap (0, stat_buf.st_size, PROT_READ, MAP_SHARED, old_file, 0); |
| 553 | |
| 554 | if (old_base == (caddr_t) -1) |
| 555 | fatal ("Can't mmap(%s): errno %d\n", old_name, errno); |
| 556 | |
| 557 | #ifdef DEBUG |
| 558 | fprintf (stderr, "mmap(%s, %x) -> %x\n", old_name, stat_buf.st_size, |
| 559 | old_base); |
| 560 | #endif |
| 561 | |
| 562 | /* Get pointers to headers & section names. */ |
| 563 | |
| 564 | old_file_h = (Elf32_Ehdr *) old_base; |
| 565 | old_program_h = (Elf32_Phdr *) ((byte *) old_base + old_file_h->e_phoff); |
| 566 | old_section_h = (Elf32_Shdr *) ((byte *) old_base + old_file_h->e_shoff); |
| 567 | old_section_names |
| 568 | = (char *) old_base + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset; |
| 569 | |
| 570 | /* Find the mdebug section, if any. */ |
| 571 | |
| 572 | old_mdebug_index = find_section (".mdebug", old_section_names, |
| 573 | old_name, old_file_h, old_section_h, 1); |
| 574 | |
| 575 | /* Find the old .bss section. */ |
| 576 | |
| 577 | old_bss_index = find_section (".bss", old_section_names, |
| 578 | old_name, old_file_h, old_section_h, 0); |
| 579 | |
| 580 | /* Find the old .data section. Figure out parameters of |
| 581 | the new data2 and bss sections. */ |
| 582 | |
| 583 | old_data_index = find_section (".data", old_section_names, |
| 584 | old_name, old_file_h, old_section_h, 0); |
| 585 | |
| 586 | old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr; |
| 587 | old_bss_size = OLD_SECTION_H (old_bss_index).sh_size; |
| 588 | #if defined(emacs) || !defined(DEBUG) |
| 589 | bss_end = (unsigned int) sbrk (0); |
| 590 | new_bss_addr = (Elf32_Addr) bss_end; |
| 591 | #else |
| 592 | new_bss_addr = old_bss_addr + old_bss_size + 0x1234; |
| 593 | #endif |
| 594 | new_data2_addr = old_bss_addr; |
| 595 | new_data2_size = new_bss_addr - old_bss_addr; |
| 596 | new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset + |
| 597 | (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr); |
| 598 | new_offsets_shift = new_bss_addr - |
| 599 | ((old_bss_addr & ~0xfff) + ((old_bss_addr & 0xfff) ? 0x1000 : 0)); |
| 600 | |
| 601 | #ifdef DEBUG |
| 602 | fprintf (stderr, "old_bss_index %d\n", old_bss_index); |
| 603 | fprintf (stderr, "old_bss_addr %x\n", old_bss_addr); |
| 604 | fprintf (stderr, "old_bss_size %x\n", old_bss_size); |
| 605 | fprintf (stderr, "new_bss_addr %x\n", new_bss_addr); |
| 606 | fprintf (stderr, "new_data2_addr %x\n", new_data2_addr); |
| 607 | fprintf (stderr, "new_data2_size %x\n", new_data2_size); |
| 608 | fprintf (stderr, "new_data2_offset %x\n", new_data2_offset); |
| 609 | fprintf (stderr, "new_offsets_shift %x\n", new_offsets_shift); |
| 610 | #endif |
| 611 | |
| 612 | if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size) |
| 613 | fatal (".bss shrank when undumping???\n", 0, 0); |
| 614 | |
| 615 | /* Set the output file to the right size and mmap it. Set |
| 616 | pointers to various interesting objects. stat_buf still has |
| 617 | old_file data. */ |
| 618 | |
| 619 | new_file = open (new_name, O_RDWR | O_CREAT, 0666); |
| 620 | if (new_file < 0) |
| 621 | fatal ("Can't creat (%s): errno %d\n", new_name, errno); |
| 622 | |
| 623 | new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_offsets_shift; |
| 624 | |
| 625 | if (ftruncate (new_file, new_file_size)) |
| 626 | fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno); |
| 627 | |
| 628 | new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_SHARED, |
| 629 | new_file, 0); |
| 630 | |
| 631 | if (new_base == (caddr_t) -1) |
| 632 | fatal ("Can't mmap (%s): errno %d\n", new_name, errno); |
| 633 | |
| 634 | new_file_h = (Elf32_Ehdr *) new_base; |
| 635 | new_program_h = (Elf32_Phdr *) ((byte *) new_base + old_file_h->e_phoff); |
| 636 | new_section_h |
| 637 | = (Elf32_Shdr *) ((byte *) new_base + old_file_h->e_shoff |
| 638 | + new_offsets_shift); |
| 639 | |
| 640 | /* Make our new file, program and section headers as copies of the |
| 641 | originals. */ |
| 642 | |
| 643 | memcpy (new_file_h, old_file_h, old_file_h->e_ehsize); |
| 644 | memcpy (new_program_h, old_program_h, |
| 645 | old_file_h->e_phnum * old_file_h->e_phentsize); |
| 646 | |
| 647 | /* Modify the e_shstrndx if necessary. */ |
| 648 | PATCH_INDEX (new_file_h->e_shstrndx); |
| 649 | |
| 650 | /* Fix up file header. We'll add one section. Section header is |
| 651 | further away now. */ |
| 652 | |
| 653 | new_file_h->e_shoff += new_offsets_shift; |
| 654 | new_file_h->e_shnum += 1; |
| 655 | |
| 656 | #ifdef DEBUG |
| 657 | fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff); |
| 658 | fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum); |
| 659 | fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff); |
| 660 | fprintf (stderr, "New section count %d\n", new_file_h->e_shnum); |
| 661 | #endif |
| 662 | |
| 663 | /* Fix up a new program header. Extend the writable data segment so |
| 664 | that the bss area is covered too. Find that segment by looking |
| 665 | for a segment that ends just before the .bss area. Make sure |
| 666 | that no segments are above the new .data2. Put a loop at the end |
| 667 | to adjust the offset and address of any segment that is above |
| 668 | data2, just in case we decide to allow this later. */ |
| 669 | |
| 670 | for (n = new_file_h->e_phnum - 1; n >= 0; n--) |
| 671 | { |
| 672 | /* Compute maximum of all requirements for alignment of section. */ |
| 673 | int alignment = (NEW_PROGRAM_H (n)).p_align; |
| 674 | if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment) |
| 675 | alignment = OLD_SECTION_H (old_bss_index).sh_addralign; |
| 676 | |
| 677 | /* Supposedly this condition is okay for the SGI. */ |
| 678 | #if 0 |
| 679 | if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr) |
| 680 | fatal ("Program segment above .bss in %s\n", old_name, 0); |
| 681 | #endif |
| 682 | |
| 683 | if (NEW_PROGRAM_H (n).p_type == PT_LOAD |
| 684 | && (round_up ((NEW_PROGRAM_H (n)).p_vaddr |
| 685 | + (NEW_PROGRAM_H (n)).p_filesz, |
| 686 | alignment) |
| 687 | == round_up (old_bss_addr, alignment))) |
| 688 | break; |
| 689 | } |
| 690 | if (n < 0) |
| 691 | fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0); |
| 692 | |
| 693 | NEW_PROGRAM_H (n).p_filesz += new_offsets_shift; |
| 694 | NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz; |
| 695 | |
| 696 | #if 1 /* Maybe allow section after data2 - does this ever happen? */ |
| 697 | for (n = new_file_h->e_phnum - 1; n >= 0; n--) |
| 698 | { |
| 699 | if (NEW_PROGRAM_H (n).p_vaddr |
| 700 | && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr) |
| 701 | NEW_PROGRAM_H (n).p_vaddr += new_offsets_shift - old_bss_size; |
| 702 | |
| 703 | if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset) |
| 704 | NEW_PROGRAM_H (n).p_offset += new_offsets_shift; |
| 705 | } |
| 706 | #endif |
| 707 | |
| 708 | /* Fix up section headers based on new .data2 section. Any section |
| 709 | whose offset or virtual address is after the new .data2 section |
| 710 | gets its value adjusted. .bss size becomes zero and new address |
| 711 | is set. data2 section header gets added by copying the existing |
| 712 | .data header and modifying the offset, address and size. */ |
| 713 | for (old_data_index = 1; old_data_index < old_file_h->e_shnum; |
| 714 | old_data_index++) |
| 715 | if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name, |
| 716 | ".data")) |
| 717 | break; |
| 718 | if (old_data_index == old_file_h->e_shnum) |
| 719 | fatal ("Can't find .data in %s.\n", old_name, 0); |
| 720 | |
| 721 | /* Walk through all section headers, insert the new data2 section right |
| 722 | before the new bss section. */ |
| 723 | for (n = 1, nn = 1; n < old_file_h->e_shnum; n++, nn++) |
| 724 | { |
| 725 | caddr_t src; |
| 726 | |
| 727 | /* If it is bss section, insert the new data2 section before it. */ |
| 728 | if (n == old_bss_index) |
| 729 | { |
| 730 | /* Steal the data section header for this data2 section. */ |
| 731 | memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index), |
| 732 | new_file_h->e_shentsize); |
| 733 | |
| 734 | NEW_SECTION_H (nn).sh_addr = new_data2_addr; |
| 735 | NEW_SECTION_H (nn).sh_offset = new_data2_offset; |
| 736 | NEW_SECTION_H (nn).sh_size = new_data2_size; |
| 737 | /* Use the bss section's alignment. This will assure that the |
| 738 | new data2 section always be placed in the same spot as the old |
| 739 | bss section by any other application. */ |
| 740 | NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign; |
| 741 | |
| 742 | /* Now copy over what we have in the memory now. */ |
| 743 | memcpy (NEW_SECTION_H (nn).sh_offset + new_base, |
| 744 | (caddr_t) OLD_SECTION_H (n).sh_addr, |
| 745 | new_data2_size); |
| 746 | nn++; |
| 747 | memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n), |
| 748 | old_file_h->e_shentsize); |
| 749 | |
| 750 | /* The new bss section's size is zero, and its file offset and virtual |
| 751 | address should be off by NEW_OFFSETS_SHIFT. */ |
| 752 | NEW_SECTION_H (nn).sh_offset += new_offsets_shift; |
| 753 | NEW_SECTION_H (nn).sh_addr = new_bss_addr; |
| 754 | /* Let the new bss section address alignment be the same as the |
| 755 | section address alignment followed the old bss section, so |
| 756 | this section will be placed in exactly the same place. */ |
| 757 | NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign; |
| 758 | NEW_SECTION_H (nn).sh_size = 0; |
| 759 | } |
| 760 | else |
| 761 | memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n), |
| 762 | old_file_h->e_shentsize); |
| 763 | |
| 764 | /* Any section that was original placed AFTER the bss |
| 765 | section must now be adjusted by NEW_OFFSETS_SHIFT. */ |
| 766 | |
| 767 | if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset) |
| 768 | NEW_SECTION_H (nn).sh_offset += new_offsets_shift; |
| 769 | |
| 770 | /* If any section hdr refers to the section after the new .data |
| 771 | section, make it refer to next one because we have inserted |
| 772 | a new section in between. */ |
| 773 | |
| 774 | PATCH_INDEX (NEW_SECTION_H (nn).sh_link); |
| 775 | /* For symbol tables, info is a symbol table index, |
| 776 | so don't change it. */ |
| 777 | if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB |
| 778 | && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM) |
| 779 | PATCH_INDEX (NEW_SECTION_H (nn).sh_info); |
| 780 | |
| 781 | /* Now, start to copy the content of sections. */ |
| 782 | if (NEW_SECTION_H (nn).sh_type == SHT_NULL |
| 783 | || NEW_SECTION_H (nn).sh_type == SHT_NOBITS) |
| 784 | continue; |
| 785 | |
| 786 | /* Write out the sections. .data and .data1 (and data2, called |
| 787 | ".data" in the strings table) get copied from the current process |
| 788 | instead of the old file. */ |
| 789 | if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data") |
| 790 | || !strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data1") |
| 791 | || !strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".got")) |
| 792 | src = (caddr_t) OLD_SECTION_H (n).sh_addr; |
| 793 | else |
| 794 | src = old_base + OLD_SECTION_H (n).sh_offset; |
| 795 | |
| 796 | memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src, |
| 797 | NEW_SECTION_H (nn).sh_size); |
| 798 | |
| 799 | /* Adjust the HDRR offsets in .mdebug and copy the |
| 800 | line data if it's in its usual 'hole' in the object. |
| 801 | Makes the new file debuggable with dbx. |
| 802 | patches up two problems: the absolute file offsets |
| 803 | in the HDRR record of .mdebug (see /usr/include/syms.h), and |
| 804 | the ld bug that gets the line table in a hole in the |
| 805 | elf file rather than in the .mdebug section proper. |
| 806 | David Anderson. davea@sgi.com Jan 16,1994. */ |
| 807 | if (n == old_mdebug_index) |
| 808 | { |
| 809 | #define MDEBUGADJUST(__ct,__fileaddr) \ |
| 810 | if (n_phdrr->__ct > 0) \ |
| 811 | { \ |
| 812 | n_phdrr->__fileaddr += movement; \ |
| 813 | } |
| 814 | |
| 815 | HDRR * o_phdrr = (HDRR *)((byte *)old_base + OLD_SECTION_H (n).sh_offset); |
| 816 | HDRR * n_phdrr = (HDRR *)((byte *)new_base + NEW_SECTION_H (nn).sh_offset); |
| 817 | unsigned movement = new_offsets_shift; |
| 818 | |
| 819 | MDEBUGADJUST (idnMax, cbDnOffset); |
| 820 | MDEBUGADJUST (ipdMax, cbPdOffset); |
| 821 | MDEBUGADJUST (isymMax, cbSymOffset); |
| 822 | MDEBUGADJUST (ioptMax, cbOptOffset); |
| 823 | MDEBUGADJUST (iauxMax, cbAuxOffset); |
| 824 | MDEBUGADJUST (issMax, cbSsOffset); |
| 825 | MDEBUGADJUST (issExtMax, cbSsExtOffset); |
| 826 | MDEBUGADJUST (ifdMax, cbFdOffset); |
| 827 | MDEBUGADJUST (crfd, cbRfdOffset); |
| 828 | MDEBUGADJUST (iextMax, cbExtOffset); |
| 829 | /* The Line Section, being possible off in a hole of the object, |
| 830 | requires special handling. */ |
| 831 | if (n_phdrr->cbLine > 0) |
| 832 | { |
| 833 | if (o_phdrr->cbLineOffset > (OLD_SECTION_H (n).sh_offset |
| 834 | + OLD_SECTION_H (n).sh_size)) |
| 835 | { |
| 836 | /* line data is in a hole in elf. do special copy and adjust |
| 837 | for this ld mistake. |
| 838 | */ |
| 839 | n_phdrr->cbLineOffset += movement; |
| 840 | |
| 841 | memcpy (n_phdrr->cbLineOffset + new_base, |
| 842 | o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine); |
| 843 | } |
| 844 | else |
| 845 | { |
| 846 | /* somehow line data is in .mdebug as it is supposed to be. */ |
| 847 | MDEBUGADJUST (cbLine, cbLineOffset); |
| 848 | } |
| 849 | } |
| 850 | } |
| 851 | |
| 852 | /* If it is the symbol table, its st_shndx field needs to be patched. */ |
| 853 | if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB |
| 854 | || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM) |
| 855 | { |
| 856 | Elf32_Shdr *spt = &NEW_SECTION_H (nn); |
| 857 | unsigned int num = spt->sh_size / spt->sh_entsize; |
| 858 | Elf32_Sym * sym = (Elf32_Sym *) (NEW_SECTION_H (nn).sh_offset |
| 859 | + new_base); |
| 860 | for (; num--; sym++) |
| 861 | { |
| 862 | if (sym->st_shndx == SHN_UNDEF |
| 863 | || sym->st_shndx == SHN_ABS |
| 864 | || sym->st_shndx == SHN_COMMON) |
| 865 | continue; |
| 866 | |
| 867 | PATCH_INDEX (sym->st_shndx); |
| 868 | } |
| 869 | } |
| 870 | } |
| 871 | |
| 872 | /* Close the files and make the new file executable. */ |
| 873 | |
| 874 | if (close (old_file)) |
| 875 | fatal ("Can't close (%s): errno %d\n", old_name, errno); |
| 876 | |
| 877 | if (close (new_file)) |
| 878 | fatal ("Can't close (%s): errno %d\n", new_name, errno); |
| 879 | |
| 880 | if (stat (new_name, &stat_buf) == -1) |
| 881 | fatal ("Can't stat (%s): errno %d\n", new_name, errno); |
| 882 | |
| 883 | n = umask (777); |
| 884 | umask (n); |
| 885 | stat_buf.st_mode |= 0111 & ~n; |
| 886 | if (chmod (new_name, stat_buf.st_mode) == -1) |
| 887 | fatal ("Can't chmod (%s): errno %d\n", new_name, errno); |
| 888 | } |