1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software developed by the Computer Systems 8 * Engineering group at Lawrence Berkeley Laboratory under DARPA contract 9 * BG 91-66 and contributed to Berkeley. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 37 #include <sys/param.h> 38 #include <sys/fnv_hash.h> 39 40 #define _WANT_VNET 41 42 #include <sys/user.h> 43 #include <sys/linker.h> 44 #include <sys/pcpu.h> 45 #include <sys/stat.h> 46 #include <sys/sysctl.h> 47 #include <sys/mman.h> 48 49 #include <stdbool.h> 50 #include <net/vnet.h> 51 52 #include <fcntl.h> 53 #include <kvm.h> 54 #include <limits.h> 55 #include <paths.h> 56 #include <stdint.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 #include <unistd.h> 61 62 #include "kvm_private.h" 63 64 SET_DECLARE(kvm_arch, struct kvm_arch); 65 66 static char _kd_is_null[] = ""; 67 68 char * 69 kvm_geterr(kvm_t *kd) 70 { 71 72 if (kd == NULL) 73 return (_kd_is_null); 74 return (kd->errbuf); 75 } 76 77 static int 78 _kvm_read_kernel_ehdr(kvm_t *kd) 79 { 80 Elf *elf; 81 82 if (elf_version(EV_CURRENT) == EV_NONE) { 83 _kvm_err(kd, kd->program, "Unsupported libelf"); 84 return (-1); 85 } 86 elf = elf_begin(kd->nlfd, ELF_C_READ, NULL); 87 if (elf == NULL) { 88 _kvm_err(kd, kd->program, "%s", elf_errmsg(0)); 89 return (-1); 90 } 91 if (elf_kind(elf) != ELF_K_ELF) { 92 _kvm_err(kd, kd->program, "kernel is not an ELF file"); 93 return (-1); 94 } 95 if (gelf_getehdr(elf, &kd->nlehdr) == NULL) { 96 _kvm_err(kd, kd->program, "%s", elf_errmsg(0)); 97 elf_end(elf); 98 return (-1); 99 } 100 elf_end(elf); 101 102 switch (kd->nlehdr.e_ident[EI_DATA]) { 103 case ELFDATA2LSB: 104 case ELFDATA2MSB: 105 return (0); 106 default: 107 _kvm_err(kd, kd->program, 108 "unsupported ELF data encoding for kernel"); 109 return (-1); 110 } 111 } 112 113 static kvm_t * 114 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout) 115 { 116 struct kvm_arch **parch; 117 struct stat st; 118 119 kd->vmfd = -1; 120 kd->pmfd = -1; 121 kd->nlfd = -1; 122 kd->vmst = NULL; 123 kd->procbase = NULL; 124 kd->argspc = NULL; 125 kd->argv = NULL; 126 127 if (uf == NULL) 128 uf = getbootfile(); 129 else if (strlen(uf) >= MAXPATHLEN) { 130 _kvm_err(kd, kd->program, "exec file name too long"); 131 goto failed; 132 } 133 if (flag & ~O_RDWR) { 134 _kvm_err(kd, kd->program, "bad flags arg"); 135 goto failed; 136 } 137 if (mf == NULL) 138 mf = _PATH_MEM; 139 140 if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) { 141 _kvm_syserr(kd, kd->program, "%s", mf); 142 goto failed; 143 } 144 if (fstat(kd->pmfd, &st) < 0) { 145 _kvm_syserr(kd, kd->program, "%s", mf); 146 goto failed; 147 } 148 if (S_ISREG(st.st_mode) && st.st_size <= 0) { 149 errno = EINVAL; 150 _kvm_syserr(kd, kd->program, "empty file"); 151 goto failed; 152 } 153 if (S_ISCHR(st.st_mode)) { 154 /* 155 * If this is a character special device, then check that 156 * it's /dev/mem. If so, open kmem too. (Maybe we should 157 * make it work for either /dev/mem or /dev/kmem -- in either 158 * case you're working with a live kernel.) 159 */ 160 if (strcmp(mf, _PATH_DEVNULL) == 0) { 161 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY | O_CLOEXEC); 162 return (kd); 163 } else if (strcmp(mf, _PATH_MEM) == 0) { 164 if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) < 165 0) { 166 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); 167 goto failed; 168 } 169 return (kd); 170 } 171 } 172 173 /* 174 * This is either a crash dump or a remote live system with its physical 175 * memory fully accessible via a special device. 176 * Open the namelist fd and determine the architecture. 177 */ 178 if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) { 179 _kvm_syserr(kd, kd->program, "%s", uf); 180 goto failed; 181 } 182 if (_kvm_read_kernel_ehdr(kd) < 0) 183 goto failed; 184 if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0 || 185 strncmp(mf, _PATH_DEVVMM, strlen(_PATH_DEVVMM)) == 0) { 186 kd->rawdump = 1; 187 kd->writable = 1; 188 } 189 SET_FOREACH(parch, kvm_arch) { 190 if ((*parch)->ka_probe(kd)) { 191 kd->arch = *parch; 192 break; 193 } 194 } 195 if (kd->arch == NULL) { 196 _kvm_err(kd, kd->program, "unsupported architecture"); 197 goto failed; 198 } 199 200 /* 201 * Non-native kernels require a symbol resolver. 202 */ 203 if (!kd->arch->ka_native(kd) && kd->resolve_symbol == NULL) { 204 _kvm_err(kd, kd->program, 205 "non-native kernel requires a symbol resolver"); 206 goto failed; 207 } 208 209 /* 210 * Initialize the virtual address translation machinery. 211 */ 212 if (kd->arch->ka_initvtop(kd) < 0) 213 goto failed; 214 return (kd); 215 failed: 216 /* 217 * Copy out the error if doing sane error semantics. 218 */ 219 if (errout != NULL) 220 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX); 221 (void)kvm_close(kd); 222 return (NULL); 223 } 224 225 kvm_t * 226 kvm_openfiles(const char *uf, const char *mf, const char *sf __unused, int flag, 227 char *errout) 228 { 229 kvm_t *kd; 230 231 if ((kd = calloc(1, sizeof(*kd))) == NULL) { 232 if (errout != NULL) 233 (void)strlcpy(errout, strerror(errno), 234 _POSIX2_LINE_MAX); 235 return (NULL); 236 } 237 return (_kvm_open(kd, uf, mf, flag, errout)); 238 } 239 240 kvm_t * 241 kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag, 242 const char *errstr) 243 { 244 kvm_t *kd; 245 246 if ((kd = calloc(1, sizeof(*kd))) == NULL) { 247 if (errstr != NULL) 248 (void)fprintf(stderr, "%s: %s\n", 249 errstr, strerror(errno)); 250 return (NULL); 251 } 252 kd->program = errstr; 253 return (_kvm_open(kd, uf, mf, flag, NULL)); 254 } 255 256 kvm_t * 257 kvm_open2(const char *uf, const char *mf, int flag, char *errout, 258 int (*resolver)(const char *, kvaddr_t *)) 259 { 260 kvm_t *kd; 261 262 if ((kd = calloc(1, sizeof(*kd))) == NULL) { 263 if (errout != NULL) 264 (void)strlcpy(errout, strerror(errno), 265 _POSIX2_LINE_MAX); 266 return (NULL); 267 } 268 kd->resolve_symbol = resolver; 269 return (_kvm_open(kd, uf, mf, flag, errout)); 270 } 271 272 int 273 kvm_close(kvm_t *kd) 274 { 275 int error = 0; 276 277 if (kd == NULL) { 278 errno = EINVAL; 279 return (-1); 280 } 281 if (kd->vmst != NULL) 282 kd->arch->ka_freevtop(kd); 283 if (kd->pmfd >= 0) 284 error |= close(kd->pmfd); 285 if (kd->vmfd >= 0) 286 error |= close(kd->vmfd); 287 if (kd->nlfd >= 0) 288 error |= close(kd->nlfd); 289 if (kd->procbase != 0) 290 free((void *)kd->procbase); 291 if (kd->argbuf != 0) 292 free((void *) kd->argbuf); 293 if (kd->argspc != 0) 294 free((void *) kd->argspc); 295 if (kd->argv != 0) 296 free((void *)kd->argv); 297 if (kd->dpcpu_initialized != 0) 298 free(kd->dpcpu_off); 299 if (kd->pt_map != NULL) 300 free(kd->pt_map); 301 if (kd->page_map != NULL) 302 free(kd->page_map); 303 if (kd->sparse_map != MAP_FAILED && kd->sparse_map != NULL) 304 munmap(kd->sparse_map, kd->pt_sparse_size); 305 free((void *)kd); 306 307 return (error); 308 } 309 310 int 311 kvm_nlist2(kvm_t *kd, struct kvm_nlist *nl) 312 { 313 314 /* 315 * If called via the public interface, permit initialization of 316 * further virtualized modules on demand. 317 */ 318 return (_kvm_nlist(kd, nl, 1)); 319 } 320 321 int 322 kvm_nlist(kvm_t *kd, struct nlist *nl) 323 { 324 struct kvm_nlist *kl; 325 int count, i, nfail; 326 327 /* 328 * Avoid reporting truncated addresses by failing for non-native 329 * cores. 330 */ 331 if (!kvm_native(kd)) { 332 _kvm_err(kd, kd->program, "kvm_nlist of non-native vmcore"); 333 return (-1); 334 } 335 336 for (count = 0; nl[count].n_name != NULL && nl[count].n_name[0] != '\0'; 337 count++) 338 ; 339 if (count == 0) 340 return (0); 341 kl = calloc(count + 1, sizeof(*kl)); 342 if (kl == NULL) { 343 _kvm_err(kd, kd->program, "cannot allocate memory"); 344 return (-1); 345 } 346 for (i = 0; i < count; i++) 347 kl[i].n_name = nl[i].n_name; 348 nfail = kvm_nlist2(kd, kl); 349 for (i = 0; i < count; i++) { 350 nl[i].n_type = kl[i].n_type; 351 nl[i].n_other = 0; 352 nl[i].n_desc = 0; 353 nl[i].n_value = kl[i].n_value; 354 } 355 free(kl); 356 return (nfail); 357 } 358 359 ssize_t 360 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) 361 { 362 363 return (kvm_read2(kd, kva, buf, len)); 364 } 365 366 ssize_t 367 kvm_read2(kvm_t *kd, kvaddr_t kva, void *buf, size_t len) 368 { 369 int cc; 370 ssize_t cr; 371 off_t pa; 372 char *cp; 373 374 if (ISALIVE(kd)) { 375 /* 376 * We're using /dev/kmem. Just read straight from the 377 * device and let the active kernel do the address translation. 378 */ 379 errno = 0; 380 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 381 _kvm_err(kd, 0, "invalid address (0x%jx)", 382 (uintmax_t)kva); 383 return (-1); 384 } 385 cr = read(kd->vmfd, buf, len); 386 if (cr < 0) { 387 _kvm_syserr(kd, 0, "kvm_read"); 388 return (-1); 389 } else if (cr < (ssize_t)len) 390 _kvm_err(kd, kd->program, "short read"); 391 return (cr); 392 } 393 394 cp = buf; 395 while (len > 0) { 396 cc = kd->arch->ka_kvatop(kd, kva, &pa); 397 if (cc == 0) 398 return (-1); 399 if (cc > (ssize_t)len) 400 cc = len; 401 errno = 0; 402 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { 403 _kvm_syserr(kd, 0, _PATH_MEM); 404 break; 405 } 406 cr = read(kd->pmfd, cp, cc); 407 if (cr < 0) { 408 _kvm_syserr(kd, kd->program, "kvm_read"); 409 break; 410 } 411 /* 412 * If ka_kvatop returns a bogus value or our core file is 413 * truncated, we might wind up seeking beyond the end of the 414 * core file in which case the read will return 0 (EOF). 415 */ 416 if (cr == 0) 417 break; 418 cp += cr; 419 kva += cr; 420 len -= cr; 421 } 422 423 return (cp - (char *)buf); 424 } 425 426 ssize_t 427 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len) 428 { 429 int cc; 430 ssize_t cw; 431 off_t pa; 432 const char *cp; 433 434 if (!ISALIVE(kd) && !kd->writable) { 435 _kvm_err(kd, kd->program, 436 "kvm_write not implemented for dead kernels"); 437 return (-1); 438 } 439 440 if (ISALIVE(kd)) { 441 /* 442 * Just like kvm_read, only we write. 443 */ 444 errno = 0; 445 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 446 _kvm_err(kd, 0, "invalid address (%lx)", kva); 447 return (-1); 448 } 449 cc = write(kd->vmfd, buf, len); 450 if (cc < 0) { 451 _kvm_syserr(kd, 0, "kvm_write"); 452 return (-1); 453 } else if ((size_t)cc < len) 454 _kvm_err(kd, kd->program, "short write"); 455 return (cc); 456 } 457 458 cp = buf; 459 while (len > 0) { 460 cc = kd->arch->ka_kvatop(kd, kva, &pa); 461 if (cc == 0) 462 return (-1); 463 if (cc > (ssize_t)len) 464 cc = len; 465 errno = 0; 466 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { 467 _kvm_syserr(kd, 0, _PATH_MEM); 468 break; 469 } 470 cw = write(kd->pmfd, cp, cc); 471 if (cw < 0) { 472 _kvm_syserr(kd, kd->program, "kvm_write"); 473 break; 474 } 475 /* 476 * If ka_kvatop returns a bogus value or our core file is 477 * truncated, we might wind up seeking beyond the end of the 478 * core file in which case the read will return 0 (EOF). 479 */ 480 if (cw == 0) 481 break; 482 cp += cw; 483 kva += cw; 484 len -= cw; 485 } 486 487 return (cp - (const char *)buf); 488 } 489 490 int 491 kvm_native(kvm_t *kd) 492 { 493 494 if (ISALIVE(kd)) 495 return (1); 496 return (kd->arch->ka_native(kd)); 497 } 498 499 int 500 kvm_walk_pages(kvm_t *kd, kvm_walk_pages_cb_t *cb, void *closure) 501 { 502 503 if (kd->arch->ka_walk_pages == NULL) 504 return (0); 505 506 return (kd->arch->ka_walk_pages(kd, cb, closure)); 507 } 508 509 kssize_t 510 kvm_kerndisp(kvm_t *kd) 511 { 512 unsigned long kernbase, rel_kernbase; 513 size_t kernbase_len = sizeof(kernbase); 514 size_t rel_kernbase_len = sizeof(rel_kernbase); 515 516 if (ISALIVE(kd)) { 517 if (sysctlbyname("kern.base_address", &kernbase, 518 &kernbase_len, NULL, 0) == -1) { 519 _kvm_syserr(kd, kd->program, 520 "failed to get kernel base address"); 521 return (0); 522 } 523 if (sysctlbyname("kern.relbase_address", &rel_kernbase, 524 &rel_kernbase_len, NULL, 0) == -1) { 525 _kvm_syserr(kd, kd->program, 526 "failed to get relocated kernel base address"); 527 return (0); 528 } 529 return (rel_kernbase - kernbase); 530 } 531 532 if (kd->arch->ka_kerndisp == NULL) 533 return (0); 534 535 return (kd->arch->ka_kerndisp(kd)); 536 } 537