Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 1 | /* Standard libdwfl callbacks for debugging the running Linux kernel. |
| 2 | Copyright (C) 2005-2011 Red Hat, Inc. |
| 3 | This file is part of Red Hat elfutils. |
| 4 | |
| 5 | Red Hat elfutils is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by the |
| 7 | Free Software Foundation; version 2 of the License. |
| 8 | |
| 9 | Red Hat elfutils is distributed in the hope that it will be useful, but |
| 10 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License along |
| 15 | with Red Hat elfutils; if not, write to the Free Software Foundation, |
| 16 | Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. |
| 17 | |
| 18 | In addition, as a special exception, Red Hat, Inc. gives You the |
| 19 | additional right to link the code of Red Hat elfutils with code licensed |
| 20 | under any Open Source Initiative certified open source license |
| 21 | (http://www.opensource.org/licenses/index.php) which requires the |
| 22 | distribution of source code with any binary distribution and to |
| 23 | distribute linked combinations of the two. Non-GPL Code permitted under |
| 24 | this exception must only link to the code of Red Hat elfutils through |
| 25 | those well defined interfaces identified in the file named EXCEPTION |
| 26 | found in the source code files (the "Approved Interfaces"). The files |
| 27 | of Non-GPL Code may instantiate templates or use macros or inline |
| 28 | functions from the Approved Interfaces without causing the resulting |
| 29 | work to be covered by the GNU General Public License. Only Red Hat, |
| 30 | Inc. may make changes or additions to the list of Approved Interfaces. |
| 31 | Red Hat's grant of this exception is conditioned upon your not adding |
| 32 | any new exceptions. If you wish to add a new Approved Interface or |
| 33 | exception, please contact Red Hat. You must obey the GNU General Public |
| 34 | License in all respects for all of the Red Hat elfutils code and other |
| 35 | code used in conjunction with Red Hat elfutils except the Non-GPL Code |
| 36 | covered by this exception. If you modify this file, you may extend this |
| 37 | exception to your version of the file, but you are not obligated to do |
| 38 | so. If you do not wish to provide this exception without modification, |
| 39 | you must delete this exception statement from your version and license |
| 40 | this file solely under the GPL without exception. |
| 41 | |
| 42 | Red Hat elfutils is an included package of the Open Invention Network. |
| 43 | An included package of the Open Invention Network is a package for which |
| 44 | Open Invention Network licensees cross-license their patents. No patent |
| 45 | license is granted, either expressly or impliedly, by designation as an |
| 46 | included package. Should you wish to participate in the Open Invention |
| 47 | Network licensing program, please visit www.openinventionnetwork.com |
| 48 | <http://www.openinventionnetwork.com>. */ |
| 49 | |
| 50 | /* We include this before config.h because it can't handle _FILE_OFFSET_BITS. |
| 51 | Everything we need here is fine if its declarations just come first. */ |
| 52 | |
Ben Cheng | 8701663 | 2013-11-20 16:22:30 -0800 | [diff] [blame] | 53 | /* TODO ANDROID - defined in AndroidConfig.h. */ |
| 54 | #undef _FILE_OFFSET_BITS |
| 55 | |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 56 | #include <fts.h> |
| 57 | |
| 58 | #include <config.h> |
| 59 | |
| 60 | #include "libdwflP.h" |
| 61 | #include <inttypes.h> |
| 62 | #include <errno.h> |
| 63 | #include <stdio.h> |
| 64 | #include <stdio_ext.h> |
| 65 | #include <string.h> |
| 66 | #include <stdlib.h> |
| 67 | #include <sys/utsname.h> |
| 68 | #include <fcntl.h> |
| 69 | #include <unistd.h> |
| 70 | |
| 71 | |
| 72 | #define KERNEL_MODNAME "kernel" |
| 73 | |
| 74 | #define MODULEDIRFMT "/lib/modules/%s" |
| 75 | |
| 76 | #define KNOTESFILE "/sys/kernel/notes" |
| 77 | #define MODNOTESFMT "/sys/module/%s/notes" |
| 78 | #define KSYMSFILE "/proc/kallsyms" |
| 79 | #define MODULELIST "/proc/modules" |
| 80 | #define SECADDRDIRFMT "/sys/module/%s/sections/" |
| 81 | #define MODULE_SECT_NAME_LEN 32 /* Minimum any linux/module.h has had. */ |
| 82 | |
| 83 | |
| 84 | #if defined (USE_ZLIB) || defined (USE_BZLIB) || defined (USE_LZMA) |
| 85 | static const char *vmlinux_suffixes[] = |
| 86 | { |
| 87 | #ifdef USE_ZLIB |
| 88 | ".gz", |
| 89 | #endif |
| 90 | #ifdef USE_BZLIB |
| 91 | ".bz2", |
| 92 | #endif |
| 93 | #ifdef USE_LZMA |
| 94 | ".xz", |
| 95 | #endif |
| 96 | }; |
| 97 | #endif |
| 98 | |
| 99 | /* Try to open the given file as it is or under the debuginfo directory. */ |
| 100 | static int |
| 101 | try_kernel_name (Dwfl *dwfl, char **fname, bool try_debug) |
| 102 | { |
| 103 | if (*fname == NULL) |
| 104 | return -1; |
| 105 | |
| 106 | /* Don't bother trying *FNAME itself here if the path will cause it to be |
| 107 | tried because we give its own basename as DEBUGLINK_FILE. */ |
| 108 | int fd = ((((dwfl->callbacks->debuginfo_path |
| 109 | ? *dwfl->callbacks->debuginfo_path : NULL) |
| 110 | ?: DEFAULT_DEBUGINFO_PATH)[0] == ':') ? -1 |
| 111 | : TEMP_FAILURE_RETRY (open64 (*fname, O_RDONLY))); |
| 112 | |
| 113 | if (fd < 0) |
| 114 | { |
| 115 | char *debugfname = NULL; |
| 116 | Dwfl_Module fakemod = { .dwfl = dwfl }; |
| 117 | /* First try the file's unadorned basename as DEBUGLINK_FILE, |
| 118 | to look for "vmlinux" files. */ |
| 119 | fd = INTUSE(dwfl_standard_find_debuginfo) (&fakemod, NULL, NULL, 0, |
| 120 | *fname, basename (*fname), 0, |
| 121 | &debugfname); |
| 122 | if (fd < 0 && try_debug) |
| 123 | /* Next, let the call use the default of basename + ".debug", |
| 124 | to look for "vmlinux.debug" files. */ |
| 125 | fd = INTUSE(dwfl_standard_find_debuginfo) (&fakemod, NULL, NULL, 0, |
| 126 | *fname, NULL, 0, |
| 127 | &debugfname); |
| 128 | if (debugfname != NULL) |
| 129 | { |
| 130 | free (*fname); |
| 131 | *fname = debugfname; |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | #if defined (USE_ZLIB) || defined (USE_BZLIB) || defined (USE_LZMA) |
| 136 | if (fd < 0) |
| 137 | for (size_t i = 0; |
| 138 | i < sizeof vmlinux_suffixes / sizeof vmlinux_suffixes[0]; |
| 139 | ++i) |
| 140 | { |
| 141 | char *zname; |
| 142 | if (asprintf (&zname, "%s%s", *fname, vmlinux_suffixes[i]) > 0) |
| 143 | { |
| 144 | fd = TEMP_FAILURE_RETRY (open64 (zname, O_RDONLY)); |
| 145 | if (fd < 0) |
| 146 | free (zname); |
| 147 | else |
| 148 | { |
| 149 | free (*fname); |
| 150 | *fname = zname; |
| 151 | } |
| 152 | } |
| 153 | } |
| 154 | #endif |
| 155 | |
| 156 | if (fd < 0) |
| 157 | { |
| 158 | free (*fname); |
| 159 | *fname = NULL; |
| 160 | } |
| 161 | |
| 162 | return fd; |
| 163 | } |
| 164 | |
| 165 | static inline const char * |
| 166 | kernel_release (void) |
| 167 | { |
| 168 | /* Cache the `uname -r` string we'll use. */ |
| 169 | static struct utsname utsname; |
| 170 | if (utsname.release[0] == '\0' && uname (&utsname) != 0) |
| 171 | return NULL; |
| 172 | return utsname.release; |
| 173 | } |
| 174 | |
| 175 | static int |
| 176 | find_kernel_elf (Dwfl *dwfl, const char *release, char **fname) |
| 177 | { |
| 178 | if ((release[0] == '/' |
| 179 | ? asprintf (fname, "%s/vmlinux", release) |
| 180 | : asprintf (fname, "/boot/vmlinux-%s", release)) < 0) |
| 181 | return -1; |
| 182 | |
| 183 | int fd = try_kernel_name (dwfl, fname, true); |
| 184 | if (fd < 0 && release[0] != '/') |
| 185 | { |
| 186 | free (*fname); |
| 187 | if (asprintf (fname, MODULEDIRFMT "/vmlinux", release) < 0) |
| 188 | return -1; |
| 189 | fd = try_kernel_name (dwfl, fname, true); |
| 190 | } |
| 191 | |
| 192 | return fd; |
| 193 | } |
| 194 | |
| 195 | static int |
| 196 | get_release (Dwfl *dwfl, const char **release) |
| 197 | { |
| 198 | if (dwfl == NULL) |
| 199 | return -1; |
| 200 | |
| 201 | const char *release_string = release == NULL ? NULL : *release; |
| 202 | if (release_string == NULL) |
| 203 | { |
| 204 | release_string = kernel_release (); |
| 205 | if (release_string == NULL) |
| 206 | return errno; |
| 207 | if (release != NULL) |
| 208 | *release = release_string; |
| 209 | } |
| 210 | |
| 211 | return 0; |
| 212 | } |
| 213 | |
| 214 | static int |
| 215 | report_kernel (Dwfl *dwfl, const char **release, |
| 216 | int (*predicate) (const char *module, const char *file)) |
| 217 | { |
| 218 | int result = get_release (dwfl, release); |
| 219 | if (unlikely (result != 0)) |
| 220 | return result; |
| 221 | |
| 222 | char *fname; |
| 223 | int fd = find_kernel_elf (dwfl, *release, &fname); |
| 224 | |
| 225 | if (fd < 0) |
| 226 | result = ((predicate != NULL && !(*predicate) (KERNEL_MODNAME, NULL)) |
| 227 | ? 0 : errno ?: ENOENT); |
| 228 | else |
| 229 | { |
| 230 | bool report = true; |
| 231 | |
| 232 | if (predicate != NULL) |
| 233 | { |
| 234 | /* Let the predicate decide whether to use this one. */ |
| 235 | int want = (*predicate) (KERNEL_MODNAME, fname); |
| 236 | if (want < 0) |
| 237 | result = errno; |
| 238 | report = want > 0; |
| 239 | } |
| 240 | |
| 241 | if (report) |
| 242 | { |
| 243 | Dwfl_Module *mod = INTUSE(dwfl_report_elf) (dwfl, KERNEL_MODNAME, |
| 244 | fname, fd, 0); |
| 245 | if (mod == NULL) |
| 246 | result = -1; |
| 247 | else |
| 248 | /* The kernel is ET_EXEC, but always treat it as relocatable. */ |
| 249 | mod->e_type = ET_DYN; |
| 250 | } |
| 251 | |
| 252 | if (!report || result < 0) |
| 253 | close (fd); |
| 254 | } |
| 255 | |
| 256 | free (fname); |
| 257 | |
| 258 | return result; |
| 259 | } |
| 260 | |
| 261 | /* Look for a kernel debug archive. If we find one, report all its modules. |
| 262 | If not, return ENOENT. */ |
| 263 | static int |
| 264 | report_kernel_archive (Dwfl *dwfl, const char **release, |
| 265 | int (*predicate) (const char *module, const char *file)) |
| 266 | { |
| 267 | int result = get_release (dwfl, release); |
| 268 | if (unlikely (result != 0)) |
| 269 | return result; |
| 270 | |
| 271 | char *archive; |
| 272 | if (unlikely ((*release)[0] == '/' |
| 273 | ? asprintf (&archive, "%s/debug.a", *release) |
| 274 | : asprintf (&archive, MODULEDIRFMT "/debug.a", *release)) < 0) |
| 275 | return ENOMEM; |
| 276 | |
| 277 | int fd = try_kernel_name (dwfl, &archive, false); |
| 278 | if (fd < 0) |
| 279 | result = errno ?: ENOENT; |
| 280 | else |
| 281 | { |
| 282 | /* We have the archive file open! */ |
| 283 | Dwfl_Module *last = __libdwfl_report_offline (dwfl, NULL, archive, fd, |
| 284 | true, predicate); |
| 285 | if (unlikely (last == NULL)) |
| 286 | result = -1; |
| 287 | else |
| 288 | { |
| 289 | /* Find the kernel and move it to the head of the list. */ |
| 290 | Dwfl_Module **tailp = &dwfl->modulelist, **prevp = tailp; |
| 291 | for (Dwfl_Module *m = *prevp; m != NULL; m = *(prevp = &m->next)) |
| 292 | if (!m->gc && m->e_type != ET_REL && !strcmp (m->name, "kernel")) |
| 293 | { |
| 294 | *prevp = m->next; |
| 295 | m->next = *tailp; |
| 296 | *tailp = m; |
| 297 | break; |
| 298 | } |
| 299 | } |
| 300 | } |
| 301 | |
| 302 | free (archive); |
| 303 | return result; |
| 304 | } |
| 305 | |
| 306 | static size_t |
| 307 | check_suffix (const FTSENT *f, size_t namelen) |
| 308 | { |
| 309 | #define TRY(sfx) \ |
| 310 | if ((namelen ? f->fts_namelen == namelen + sizeof sfx - 1 \ |
| 311 | : f->fts_namelen >= sizeof sfx) \ |
| 312 | && !memcmp (f->fts_name + f->fts_namelen - (sizeof sfx - 1), \ |
| 313 | sfx, sizeof sfx)) \ |
| 314 | return sizeof sfx - 1 |
| 315 | |
| 316 | TRY (".ko"); |
| 317 | #if USE_ZLIB |
| 318 | TRY (".ko.gz"); |
| 319 | #endif |
| 320 | #if USE_BZLIB |
| 321 | TRY (".ko.bz2"); |
| 322 | #endif |
| 323 | |
| 324 | return 0; |
| 325 | |
| 326 | #undef TRY |
| 327 | } |
| 328 | |
| 329 | /* Report a kernel and all its modules found on disk, for offline use. |
| 330 | If RELEASE starts with '/', it names a directory to look in; |
| 331 | if not, it names a directory to find under /lib/modules/; |
| 332 | if null, /lib/modules/`uname -r` is used. |
| 333 | Returns zero on success, -1 if dwfl_report_module failed, |
| 334 | or an errno code if finding the files on disk failed. */ |
| 335 | int |
| 336 | dwfl_linux_kernel_report_offline (Dwfl *dwfl, const char *release, |
| 337 | int (*predicate) (const char *module, |
| 338 | const char *file)) |
| 339 | { |
| 340 | int result = report_kernel_archive (dwfl, &release, predicate); |
| 341 | if (result != ENOENT) |
| 342 | return result; |
| 343 | |
| 344 | /* First report the kernel. */ |
| 345 | result = report_kernel (dwfl, &release, predicate); |
| 346 | if (result == 0) |
| 347 | { |
| 348 | /* Do "find /lib/modules/RELEASE -name *.ko". */ |
| 349 | |
| 350 | char *modulesdir[] = { NULL, NULL }; |
| 351 | if (release[0] == '/') |
| 352 | modulesdir[0] = (char *) release; |
| 353 | else |
| 354 | { |
| 355 | if (asprintf (&modulesdir[0], MODULEDIRFMT, release) < 0) |
| 356 | return errno; |
| 357 | } |
| 358 | |
| 359 | FTS *fts = fts_open (modulesdir, FTS_NOSTAT | FTS_LOGICAL, NULL); |
| 360 | if (modulesdir[0] == (char *) release) |
| 361 | modulesdir[0] = NULL; |
| 362 | if (fts == NULL) |
| 363 | { |
| 364 | free (modulesdir[0]); |
| 365 | return errno; |
| 366 | } |
| 367 | |
| 368 | FTSENT *f; |
| 369 | while ((f = fts_read (fts)) != NULL) |
| 370 | { |
| 371 | /* Skip a "source" subtree, which tends to be large. |
| 372 | This insane hard-coding of names is what depmod does too. */ |
| 373 | if (f->fts_namelen == sizeof "source" - 1 |
| 374 | && !strcmp (f->fts_name, "source")) |
| 375 | { |
| 376 | fts_set (fts, f, FTS_SKIP); |
| 377 | continue; |
| 378 | } |
| 379 | |
| 380 | switch (f->fts_info) |
| 381 | { |
| 382 | case FTS_F: |
| 383 | case FTS_SL: |
| 384 | case FTS_NSOK:; |
| 385 | /* See if this file name matches "*.ko". */ |
| 386 | const size_t suffix = check_suffix (f, 0); |
| 387 | if (suffix) |
| 388 | { |
| 389 | /* We have a .ko file to report. Following the algorithm |
| 390 | by which the kernel makefiles set KBUILD_MODNAME, we |
| 391 | replace all ',' or '-' with '_' in the file name and |
| 392 | call that the module name. Modules could well be |
| 393 | built using different embedded names than their file |
| 394 | names. To handle that, we would have to look at the |
| 395 | __this_module.name contents in the module's text. */ |
| 396 | |
| 397 | char name[f->fts_namelen - suffix + 1]; |
| 398 | for (size_t i = 0; i < f->fts_namelen - 3U; ++i) |
| 399 | if (f->fts_name[i] == '-' || f->fts_name[i] == ',') |
| 400 | name[i] = '_'; |
| 401 | else |
| 402 | name[i] = f->fts_name[i]; |
| 403 | name[f->fts_namelen - suffix] = '\0'; |
| 404 | |
| 405 | if (predicate != NULL) |
| 406 | { |
| 407 | /* Let the predicate decide whether to use this one. */ |
| 408 | int want = (*predicate) (name, f->fts_path); |
| 409 | if (want < 0) |
| 410 | { |
| 411 | result = -1; |
| 412 | break; |
| 413 | } |
| 414 | if (!want) |
| 415 | continue; |
| 416 | } |
| 417 | |
| 418 | if (dwfl_report_offline (dwfl, name, f->fts_path, -1) == NULL) |
| 419 | { |
| 420 | result = -1; |
| 421 | break; |
| 422 | } |
| 423 | } |
| 424 | continue; |
| 425 | |
| 426 | case FTS_ERR: |
| 427 | case FTS_DNR: |
| 428 | case FTS_NS: |
| 429 | result = f->fts_errno; |
| 430 | break; |
| 431 | |
| 432 | case FTS_SLNONE: |
| 433 | default: |
| 434 | continue; |
| 435 | } |
| 436 | |
| 437 | /* We only get here in error cases. */ |
| 438 | break; |
| 439 | } |
| 440 | fts_close (fts); |
| 441 | free (modulesdir[0]); |
| 442 | } |
| 443 | |
| 444 | return result; |
| 445 | } |
| 446 | INTDEF (dwfl_linux_kernel_report_offline) |
| 447 | |
| 448 | |
| 449 | /* Grovel around to guess the bounds of the runtime kernel image. */ |
| 450 | static int |
| 451 | intuit_kernel_bounds (Dwarf_Addr *start, Dwarf_Addr *end, Dwarf_Addr *notes) |
| 452 | { |
| 453 | FILE *f = fopen (KSYMSFILE, "r"); |
| 454 | if (f == NULL) |
| 455 | return errno; |
| 456 | |
| 457 | (void) __fsetlocking (f, FSETLOCKING_BYCALLER); |
| 458 | |
| 459 | *notes = 0; |
| 460 | |
| 461 | char *line = NULL; |
| 462 | size_t linesz = 0; |
| 463 | size_t n; |
| 464 | char *p = NULL; |
| 465 | const char *type; |
| 466 | |
| 467 | inline bool read_address (Dwarf_Addr *addr) |
| 468 | { |
| 469 | if ((n = getline (&line, &linesz, f)) < 1 || line[n - 2] == ']') |
| 470 | return false; |
| 471 | *addr = strtoull (line, &p, 16); |
| 472 | p += strspn (p, " \t"); |
| 473 | type = strsep (&p, " \t\n"); |
| 474 | if (type == NULL) |
| 475 | return false; |
| 476 | return p != NULL && p != line; |
| 477 | } |
| 478 | |
| 479 | int result; |
| 480 | do |
| 481 | result = read_address (start) ? 0 : -1; |
| 482 | while (result == 0 && strchr ("TtRr", *type) == NULL); |
| 483 | |
| 484 | if (result == 0) |
| 485 | { |
| 486 | *end = *start; |
| 487 | while (read_address (end)) |
| 488 | if (*notes == 0 && !strcmp (p, "__start_notes\n")) |
| 489 | *notes = *end; |
| 490 | |
| 491 | Dwarf_Addr round_kernel = sysconf (_SC_PAGE_SIZE); |
| 492 | *start &= -(Dwarf_Addr) round_kernel; |
| 493 | *end += round_kernel - 1; |
| 494 | *end &= -(Dwarf_Addr) round_kernel; |
| 495 | if (*start >= *end || *end - *start < round_kernel) |
| 496 | result = -1; |
| 497 | } |
| 498 | free (line); |
| 499 | |
| 500 | if (result == -1) |
| 501 | result = ferror_unlocked (f) ? errno : ENOEXEC; |
| 502 | |
| 503 | fclose (f); |
| 504 | |
| 505 | return result; |
| 506 | } |
| 507 | |
| 508 | |
| 509 | /* Look for a build ID note in NOTESFILE and associate the ID with MOD. */ |
| 510 | static int |
| 511 | check_notes (Dwfl_Module *mod, const char *notesfile, |
| 512 | Dwarf_Addr vaddr, const char *secname) |
| 513 | { |
| 514 | int fd = open64 (notesfile, O_RDONLY); |
| 515 | if (fd < 0) |
| 516 | return 1; |
| 517 | |
| 518 | assert (sizeof (Elf32_Nhdr) == sizeof (GElf_Nhdr)); |
| 519 | assert (sizeof (Elf64_Nhdr) == sizeof (GElf_Nhdr)); |
| 520 | union |
| 521 | { |
| 522 | GElf_Nhdr nhdr; |
| 523 | unsigned char data[8192]; |
| 524 | } buf; |
| 525 | |
| 526 | ssize_t n = read (fd, buf.data, sizeof buf); |
| 527 | close (fd); |
| 528 | |
| 529 | if (n <= 0) |
| 530 | return 1; |
| 531 | |
| 532 | unsigned char *p = buf.data; |
| 533 | while (p < &buf.data[n]) |
| 534 | { |
| 535 | /* No translation required since we are reading the native kernel. */ |
| 536 | GElf_Nhdr *nhdr = (void *) p; |
| 537 | p += sizeof *nhdr; |
| 538 | unsigned char *name = p; |
| 539 | p += (nhdr->n_namesz + 3) & -4U; |
| 540 | unsigned char *bits = p; |
| 541 | p += (nhdr->n_descsz + 3) & -4U; |
| 542 | |
| 543 | if (p <= &buf.data[n] |
| 544 | && nhdr->n_type == NT_GNU_BUILD_ID |
| 545 | && nhdr->n_namesz == sizeof "GNU" |
| 546 | && !memcmp (name, "GNU", sizeof "GNU")) |
| 547 | { |
| 548 | /* Found it. For a module we must figure out its VADDR now. */ |
| 549 | |
| 550 | if (secname != NULL |
| 551 | && (INTUSE(dwfl_linux_kernel_module_section_address) |
| 552 | (mod, NULL, mod->name, 0, secname, 0, NULL, &vaddr) != 0 |
| 553 | || vaddr == (GElf_Addr) -1l)) |
| 554 | vaddr = 0; |
| 555 | |
| 556 | if (vaddr != 0) |
| 557 | vaddr += bits - buf.data; |
| 558 | return INTUSE(dwfl_module_report_build_id) (mod, bits, |
| 559 | nhdr->n_descsz, vaddr); |
| 560 | } |
| 561 | } |
| 562 | |
| 563 | return 0; |
| 564 | } |
| 565 | |
| 566 | /* Look for a build ID for the kernel. */ |
| 567 | static int |
| 568 | check_kernel_notes (Dwfl_Module *kernelmod, GElf_Addr vaddr) |
| 569 | { |
| 570 | return check_notes (kernelmod, KNOTESFILE, vaddr, NULL) < 0 ? -1 : 0; |
| 571 | } |
| 572 | |
| 573 | /* Look for a build ID for a loaded kernel module. */ |
| 574 | static int |
| 575 | check_module_notes (Dwfl_Module *mod) |
| 576 | { |
| 577 | char *dirs[2] = { NULL, NULL }; |
| 578 | if (asprintf (&dirs[0], MODNOTESFMT, mod->name) < 0) |
| 579 | return ENOMEM; |
| 580 | |
| 581 | FTS *fts = fts_open (dirs, FTS_NOSTAT | FTS_LOGICAL, NULL); |
| 582 | if (fts == NULL) |
| 583 | { |
| 584 | free (dirs[0]); |
| 585 | return 0; |
| 586 | } |
| 587 | |
| 588 | int result = 0; |
| 589 | FTSENT *f; |
| 590 | while ((f = fts_read (fts)) != NULL) |
| 591 | { |
| 592 | switch (f->fts_info) |
| 593 | { |
| 594 | case FTS_F: |
| 595 | case FTS_SL: |
| 596 | case FTS_NSOK: |
| 597 | result = check_notes (mod, f->fts_accpath, 0, f->fts_name); |
| 598 | if (result > 0) /* Nothing found. */ |
| 599 | { |
| 600 | result = 0; |
| 601 | continue; |
| 602 | } |
| 603 | break; |
| 604 | |
| 605 | case FTS_ERR: |
| 606 | case FTS_DNR: |
| 607 | result = f->fts_errno; |
| 608 | break; |
| 609 | |
| 610 | case FTS_NS: |
| 611 | case FTS_SLNONE: |
| 612 | default: |
| 613 | continue; |
| 614 | } |
| 615 | |
| 616 | /* We only get here when finished or in error cases. */ |
| 617 | break; |
| 618 | } |
| 619 | fts_close (fts); |
| 620 | free (dirs[0]); |
| 621 | |
| 622 | return result; |
| 623 | } |
| 624 | |
| 625 | int |
| 626 | dwfl_linux_kernel_report_kernel (Dwfl *dwfl) |
| 627 | { |
| 628 | Dwarf_Addr start; |
| 629 | Dwarf_Addr end; |
| 630 | inline Dwfl_Module *report (void) |
| 631 | { |
| 632 | return INTUSE(dwfl_report_module) (dwfl, KERNEL_MODNAME, start, end); |
| 633 | } |
| 634 | |
| 635 | /* This is a bit of a kludge. If we already reported the kernel, |
| 636 | don't bother figuring it out again--it never changes. */ |
| 637 | for (Dwfl_Module *m = dwfl->modulelist; m != NULL; m = m->next) |
| 638 | if (!strcmp (m->name, KERNEL_MODNAME)) |
| 639 | { |
| 640 | start = m->low_addr; |
| 641 | end = m->high_addr; |
| 642 | return report () == NULL ? -1 : 0; |
| 643 | } |
| 644 | |
| 645 | /* Try to figure out the bounds of the kernel image without |
| 646 | looking for any vmlinux file. */ |
| 647 | Dwarf_Addr notes; |
| 648 | /* The compiler cannot deduce that if intuit_kernel_bounds returns |
| 649 | zero NOTES will be initialized. Fake the initialization. */ |
| 650 | asm ("" : "=m" (notes)); |
| 651 | int result = intuit_kernel_bounds (&start, &end, ¬es); |
| 652 | if (result == 0) |
| 653 | { |
| 654 | Dwfl_Module *mod = report (); |
| 655 | return unlikely (mod == NULL) ? -1 : check_kernel_notes (mod, notes); |
| 656 | } |
| 657 | if (result != ENOENT) |
| 658 | return result; |
| 659 | |
| 660 | /* Find the ELF file for the running kernel and dwfl_report_elf it. */ |
| 661 | return report_kernel (dwfl, NULL, NULL); |
| 662 | } |
| 663 | INTDEF (dwfl_linux_kernel_report_kernel) |
| 664 | |
| 665 | |
| 666 | /* Dwfl_Callbacks.find_elf for the running Linux kernel and its modules. */ |
| 667 | |
| 668 | int |
| 669 | dwfl_linux_kernel_find_elf (Dwfl_Module *mod, |
| 670 | void **userdata __attribute__ ((unused)), |
| 671 | const char *module_name, |
| 672 | Dwarf_Addr base __attribute__ ((unused)), |
| 673 | char **file_name, Elf **elfp) |
| 674 | { |
| 675 | if (mod->build_id_len > 0) |
| 676 | { |
| 677 | int fd = INTUSE(dwfl_build_id_find_elf) (mod, NULL, NULL, 0, |
| 678 | file_name, elfp); |
| 679 | if (fd >= 0 || mod->main.elf != NULL || errno != 0) |
| 680 | return fd; |
| 681 | } |
| 682 | |
| 683 | const char *release = kernel_release (); |
| 684 | if (release == NULL) |
| 685 | return errno; |
| 686 | |
| 687 | if (!strcmp (module_name, KERNEL_MODNAME)) |
| 688 | return find_kernel_elf (mod->dwfl, release, file_name); |
| 689 | |
| 690 | /* Do "find /lib/modules/`uname -r` -name MODULE_NAME.ko". */ |
| 691 | |
| 692 | char *modulesdir[] = { NULL, NULL }; |
| 693 | if (asprintf (&modulesdir[0], MODULEDIRFMT, release) < 0) |
| 694 | return -1; |
| 695 | |
| 696 | FTS *fts = fts_open (modulesdir, FTS_NOSTAT | FTS_LOGICAL, NULL); |
| 697 | if (fts == NULL) |
| 698 | { |
| 699 | free (modulesdir[0]); |
| 700 | return -1; |
| 701 | } |
| 702 | |
| 703 | size_t namelen = strlen (module_name); |
| 704 | |
| 705 | /* This is a kludge. There is no actual necessary relationship between |
| 706 | the name of the .ko file installed and the module name the kernel |
| 707 | knows it by when it's loaded. The kernel's only idea of the module |
| 708 | name comes from the name embedded in the object's magic |
| 709 | .gnu.linkonce.this_module section. |
| 710 | |
| 711 | In practice, these module names match the .ko file names except for |
| 712 | some using '_' and some using '-'. So our cheap kludge is to look for |
| 713 | two files when either a '_' or '-' appears in a module name, one using |
| 714 | only '_' and one only using '-'. */ |
| 715 | |
| 716 | char alternate_name[namelen + 1]; |
| 717 | inline bool subst_name (char from, char to) |
| 718 | { |
| 719 | const char *n = memchr (module_name, from, namelen); |
| 720 | if (n == NULL) |
| 721 | return false; |
| 722 | char *a = mempcpy (alternate_name, module_name, n - module_name); |
| 723 | *a++ = to; |
| 724 | ++n; |
| 725 | const char *p; |
| 726 | while ((p = memchr (n, from, namelen - (n - module_name))) != NULL) |
| 727 | { |
| 728 | a = mempcpy (a, n, p - n); |
| 729 | *a++ = to; |
| 730 | n = p + 1; |
| 731 | } |
| 732 | memcpy (a, n, namelen - (n - module_name) + 1); |
| 733 | return true; |
| 734 | } |
| 735 | if (!subst_name ('-', '_') && !subst_name ('_', '-')) |
| 736 | alternate_name[0] = '\0'; |
| 737 | |
| 738 | FTSENT *f; |
| 739 | int error = ENOENT; |
| 740 | while ((f = fts_read (fts)) != NULL) |
| 741 | { |
| 742 | /* Skip a "source" subtree, which tends to be large. |
| 743 | This insane hard-coding of names is what depmod does too. */ |
| 744 | if (f->fts_namelen == sizeof "source" - 1 |
| 745 | && !strcmp (f->fts_name, "source")) |
| 746 | { |
| 747 | fts_set (fts, f, FTS_SKIP); |
| 748 | continue; |
| 749 | } |
| 750 | |
| 751 | error = ENOENT; |
| 752 | switch (f->fts_info) |
| 753 | { |
| 754 | case FTS_F: |
| 755 | case FTS_SL: |
| 756 | case FTS_NSOK: |
| 757 | /* See if this file name is "MODULE_NAME.ko". */ |
| 758 | if (check_suffix (f, namelen) |
| 759 | && (!memcmp (f->fts_name, module_name, namelen) |
| 760 | || !memcmp (f->fts_name, alternate_name, namelen))) |
| 761 | { |
| 762 | int fd = open64 (f->fts_accpath, O_RDONLY); |
| 763 | *file_name = strdup (f->fts_path); |
| 764 | fts_close (fts); |
| 765 | free (modulesdir[0]); |
| 766 | if (fd < 0) |
| 767 | free (*file_name); |
| 768 | else if (*file_name == NULL) |
| 769 | { |
| 770 | close (fd); |
| 771 | fd = -1; |
| 772 | } |
| 773 | return fd; |
| 774 | } |
| 775 | break; |
| 776 | |
| 777 | case FTS_ERR: |
| 778 | case FTS_DNR: |
| 779 | case FTS_NS: |
| 780 | error = f->fts_errno; |
| 781 | break; |
| 782 | |
| 783 | case FTS_SLNONE: |
| 784 | default: |
| 785 | break; |
| 786 | } |
| 787 | } |
| 788 | |
| 789 | fts_close (fts); |
| 790 | free (modulesdir[0]); |
| 791 | errno = error; |
| 792 | return -1; |
| 793 | } |
| 794 | INTDEF (dwfl_linux_kernel_find_elf) |
| 795 | |
| 796 | |
| 797 | /* Dwfl_Callbacks.section_address for kernel modules in the running Linux. |
| 798 | We read the information from /sys/module directly. */ |
| 799 | |
| 800 | int |
| 801 | dwfl_linux_kernel_module_section_address |
| 802 | (Dwfl_Module *mod __attribute__ ((unused)), |
| 803 | void **userdata __attribute__ ((unused)), |
| 804 | const char *modname, Dwarf_Addr base __attribute__ ((unused)), |
| 805 | const char *secname, Elf32_Word shndx __attribute__ ((unused)), |
| 806 | const GElf_Shdr *shdr __attribute__ ((unused)), |
| 807 | Dwarf_Addr *addr) |
| 808 | { |
| 809 | char *sysfile; |
| 810 | if (asprintf (&sysfile, SECADDRDIRFMT "%s", modname, secname) < 0) |
| 811 | return DWARF_CB_ABORT; |
| 812 | |
| 813 | FILE *f = fopen (sysfile, "r"); |
| 814 | free (sysfile); |
| 815 | |
| 816 | if (f == NULL) |
| 817 | { |
| 818 | if (errno == ENOENT) |
| 819 | { |
| 820 | /* The .modinfo and .data.percpu sections are never kept |
| 821 | loaded in the kernel. If the kernel was compiled without |
| 822 | CONFIG_MODULE_UNLOAD, the .exit.* sections are not |
| 823 | actually loaded at all. |
| 824 | |
| 825 | Setting *ADDR to -1 tells the caller this section is |
| 826 | actually absent from memory. */ |
| 827 | |
| 828 | if (!strcmp (secname, ".modinfo") |
| 829 | || !strcmp (secname, ".data.percpu") |
| 830 | || !strncmp (secname, ".exit", 5)) |
| 831 | { |
| 832 | *addr = (Dwarf_Addr) -1l; |
| 833 | return DWARF_CB_OK; |
| 834 | } |
| 835 | |
| 836 | /* The goofy PPC64 module_frob_arch_sections function tweaks |
| 837 | the section names as a way to control other kernel code's |
| 838 | behavior, and this cruft leaks out into the /sys information. |
| 839 | The file name for ".init*" may actually look like "_init*". */ |
| 840 | |
| 841 | const bool is_init = !strncmp (secname, ".init", 5); |
| 842 | if (is_init) |
| 843 | { |
| 844 | if (asprintf (&sysfile, SECADDRDIRFMT "_%s", |
| 845 | modname, &secname[1]) < 0) |
| 846 | return ENOMEM; |
| 847 | f = fopen (sysfile, "r"); |
| 848 | free (sysfile); |
| 849 | if (f != NULL) |
| 850 | goto ok; |
| 851 | } |
| 852 | |
| 853 | /* The kernel truncates section names to MODULE_SECT_NAME_LEN - 1. |
| 854 | In case that size increases in the future, look for longer |
| 855 | truncated names first. */ |
| 856 | size_t namelen = strlen (secname); |
| 857 | if (namelen >= MODULE_SECT_NAME_LEN) |
| 858 | { |
| 859 | int len = asprintf (&sysfile, SECADDRDIRFMT "%s", |
| 860 | modname, secname); |
| 861 | if (len < 0) |
| 862 | return DWARF_CB_ABORT; |
| 863 | char *end = sysfile + len; |
| 864 | do |
| 865 | { |
| 866 | *--end = '\0'; |
| 867 | f = fopen (sysfile, "r"); |
| 868 | if (is_init && f == NULL && errno == ENOENT) |
| 869 | { |
| 870 | sysfile[len - namelen] = '_'; |
| 871 | f = fopen (sysfile, "r"); |
| 872 | sysfile[len - namelen] = '.'; |
| 873 | } |
| 874 | } |
| 875 | while (f == NULL && errno == ENOENT |
| 876 | && end - &sysfile[len - namelen] >= MODULE_SECT_NAME_LEN); |
| 877 | free (sysfile); |
| 878 | |
| 879 | if (f != NULL) |
| 880 | goto ok; |
| 881 | } |
| 882 | } |
| 883 | |
| 884 | return DWARF_CB_ABORT; |
| 885 | } |
| 886 | |
| 887 | ok: |
| 888 | (void) __fsetlocking (f, FSETLOCKING_BYCALLER); |
| 889 | |
| 890 | int result = (fscanf (f, "%" PRIx64 "\n", addr) == 1 ? 0 |
| 891 | : ferror_unlocked (f) ? errno : ENOEXEC); |
| 892 | fclose (f); |
| 893 | |
| 894 | if (result == 0) |
| 895 | return DWARF_CB_OK; |
| 896 | |
| 897 | errno = result; |
| 898 | return DWARF_CB_ABORT; |
| 899 | } |
| 900 | INTDEF (dwfl_linux_kernel_module_section_address) |
| 901 | |
| 902 | int |
| 903 | dwfl_linux_kernel_report_modules (Dwfl *dwfl) |
| 904 | { |
| 905 | FILE *f = fopen (MODULELIST, "r"); |
| 906 | if (f == NULL) |
| 907 | return errno; |
| 908 | |
| 909 | (void) __fsetlocking (f, FSETLOCKING_BYCALLER); |
| 910 | |
| 911 | int result = 0; |
| 912 | Dwarf_Addr modaddr; |
| 913 | unsigned long int modsz; |
| 914 | char modname[128]; |
| 915 | char *line = NULL; |
| 916 | size_t linesz = 0; |
| 917 | /* We can't just use fscanf here because it's not easy to distinguish \n |
| 918 | from other whitespace so as to take the optional word following the |
| 919 | address but always stop at the end of the line. */ |
| 920 | while (getline (&line, &linesz, f) > 0 |
| 921 | && sscanf (line, "%128s %lu %*s %*s %*s %" PRIx64 " %*s\n", |
| 922 | modname, &modsz, &modaddr) == 3) |
| 923 | { |
| 924 | Dwfl_Module *mod = INTUSE(dwfl_report_module) (dwfl, modname, |
| 925 | modaddr, modaddr + modsz); |
| 926 | if (mod == NULL) |
| 927 | { |
| 928 | result = -1; |
| 929 | break; |
| 930 | } |
| 931 | |
| 932 | result = check_module_notes (mod); |
| 933 | } |
| 934 | free (line); |
| 935 | |
| 936 | if (result == 0) |
| 937 | result = ferror_unlocked (f) ? errno : feof_unlocked (f) ? 0 : ENOEXEC; |
| 938 | |
| 939 | fclose (f); |
| 940 | |
| 941 | return result; |
| 942 | } |
| 943 | INTDEF (dwfl_linux_kernel_report_modules) |