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 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 __SCCSID("@(#)kvm.c 8.2 (Berkeley) 2/13/94"); 39 40 #include <sys/param.h> 41 #include <sys/fnv_hash.h> 42 43 #define _WANT_VNET 44 45 #include <sys/user.h> 46 #include <sys/linker.h> 47 #include <sys/pcpu.h> 48 #include <sys/stat.h> 49 #include <sys/mman.h> 50 51 #include <net/vnet.h> 52 53 #include <fcntl.h> 54 #include <kvm.h> 55 #include <limits.h> 56 #include <paths.h> 57 #include <stdint.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "kvm_private.h" 64 65 SET_DECLARE(kvm_arch, struct kvm_arch); 66 67 static char _kd_is_null[] = ""; 68 69 char * 70 kvm_geterr(kvm_t *kd) 71 { 72 73 if (kd == NULL) 74 return (_kd_is_null); 75 return (kd->errbuf); 76 } 77 78 static int 79 _kvm_read_kernel_ehdr(kvm_t *kd) 80 { 81 Elf *elf; 82 83 if (elf_version(EV_CURRENT) == EV_NONE) { 84 _kvm_err(kd, kd->program, "Unsupported libelf"); 85 return (-1); 86 } 87 elf = elf_begin(kd->nlfd, ELF_C_READ, NULL); 88 if (elf == NULL) { 89 _kvm_err(kd, kd->program, "%s", elf_errmsg(0)); 90 return (-1); 91 } 92 if (elf_kind(elf) != ELF_K_ELF) { 93 _kvm_err(kd, kd->program, "kernel is not an ELF file"); 94 return (-1); 95 } 96 if (gelf_getehdr(elf, &kd->nlehdr) == NULL) { 97 _kvm_err(kd, kd->program, "%s", elf_errmsg(0)); 98 elf_end(elf); 99 return (-1); 100 } 101 elf_end(elf); 102 103 switch (kd->nlehdr.e_ident[EI_DATA]) { 104 case ELFDATA2LSB: 105 case ELFDATA2MSB: 106 return (0); 107 default: 108 _kvm_err(kd, kd->program, 109 "unsupported ELF data encoding for kernel"); 110 return (-1); 111 } 112 } 113 114 static kvm_t * 115 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout) 116 { 117 struct kvm_arch **parch; 118 struct stat st; 119 120 kd->vmfd = -1; 121 kd->pmfd = -1; 122 kd->nlfd = -1; 123 kd->vmst = NULL; 124 kd->procbase = NULL; 125 kd->argspc = NULL; 126 kd->argv = NULL; 127 128 if (uf == NULL) 129 uf = getbootfile(); 130 else if (strlen(uf) >= MAXPATHLEN) { 131 _kvm_err(kd, kd->program, "exec file name too long"); 132 goto failed; 133 } 134 if (flag & ~O_RDWR) { 135 _kvm_err(kd, kd->program, "bad flags arg"); 136 goto failed; 137 } 138 if (mf == NULL) 139 mf = _PATH_MEM; 140 141 if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) { 142 _kvm_syserr(kd, kd->program, "%s", mf); 143 goto failed; 144 } 145 if (fstat(kd->pmfd, &st) < 0) { 146 _kvm_syserr(kd, kd->program, "%s", mf); 147 goto failed; 148 } 149 if (S_ISREG(st.st_mode) && st.st_size <= 0) { 150 errno = EINVAL; 151 _kvm_syserr(kd, kd->program, "empty file"); 152 goto failed; 153 } 154 if (S_ISCHR(st.st_mode)) { 155 /* 156 * If this is a character special device, then check that 157 * it's /dev/mem. If so, open kmem too. (Maybe we should 158 * make it work for either /dev/mem or /dev/kmem -- in either 159 * case you're working with a live kernel.) 160 */ 161 if (strcmp(mf, _PATH_DEVNULL) == 0) { 162 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY | O_CLOEXEC); 163 return (kd); 164 } else if (strcmp(mf, _PATH_MEM) == 0) { 165 if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) < 166 0) { 167 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); 168 goto failed; 169 } 170 return (kd); 171 } 172 } 173 174 /* 175 * This is either a crash dump or a remote live system with its physical 176 * memory fully accessible via a special device. 177 * Open the namelist fd and determine the architecture. 178 */ 179 if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) { 180 _kvm_syserr(kd, kd->program, "%s", uf); 181 goto failed; 182 } 183 if (_kvm_read_kernel_ehdr(kd) < 0) 184 goto failed; 185 if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0 || 186 strncmp(mf, _PATH_DEVVMM, strlen(_PATH_DEVVMM)) == 0) { 187 kd->rawdump = 1; 188 kd->writable = 1; 189 } 190 SET_FOREACH(parch, kvm_arch) { 191 if ((*parch)->ka_probe(kd)) { 192 kd->arch = *parch; 193 break; 194 } 195 } 196 if (kd->arch == NULL) { 197 _kvm_err(kd, kd->program, "unsupported architecture"); 198 goto failed; 199 } 200 201 /* 202 * Non-native kernels require a symbol resolver. 203 */ 204 if (!kd->arch->ka_native(kd) && kd->resolve_symbol == NULL) { 205 _kvm_err(kd, kd->program, 206 "non-native kernel requires a symbol resolver"); 207 goto failed; 208 } 209 210 /* 211 * Initialize the virtual address translation machinery. 212 */ 213 if (kd->arch->ka_initvtop(kd) < 0) 214 goto failed; 215 return (kd); 216 failed: 217 /* 218 * Copy out the error if doing sane error semantics. 219 */ 220 if (errout != NULL) 221 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX); 222 (void)kvm_close(kd); 223 return (NULL); 224 } 225 226 kvm_t * 227 kvm_openfiles(const char *uf, const char *mf, const char *sf __unused, int flag, 228 char *errout) 229 { 230 kvm_t *kd; 231 232 if ((kd = calloc(1, sizeof(*kd))) == NULL) { 233 if (errout != NULL) 234 (void)strlcpy(errout, strerror(errno), 235 _POSIX2_LINE_MAX); 236 return (NULL); 237 } 238 return (_kvm_open(kd, uf, mf, flag, errout)); 239 } 240 241 kvm_t * 242 kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag, 243 const char *errstr) 244 { 245 kvm_t *kd; 246 247 if ((kd = calloc(1, sizeof(*kd))) == NULL) { 248 if (errstr != NULL) 249 (void)fprintf(stderr, "%s: %s\n", 250 errstr, strerror(errno)); 251 return (NULL); 252 } 253 kd->program = errstr; 254 return (_kvm_open(kd, uf, mf, flag, NULL)); 255 } 256 257 kvm_t * 258 kvm_open2(const char *uf, const char *mf, int flag, char *errout, 259 int (*resolver)(const char *, kvaddr_t *)) 260 { 261 kvm_t *kd; 262 263 if ((kd = calloc(1, sizeof(*kd))) == NULL) { 264 if (errout != NULL) 265 (void)strlcpy(errout, strerror(errno), 266 _POSIX2_LINE_MAX); 267 return (NULL); 268 } 269 kd->resolve_symbol = resolver; 270 return (_kvm_open(kd, uf, mf, flag, errout)); 271 } 272 273 int 274 kvm_close(kvm_t *kd) 275 { 276 int error = 0; 277 278 if (kd == NULL) { 279 errno = EINVAL; 280 return (-1); 281 } 282 if (kd->vmst != NULL) 283 kd->arch->ka_freevtop(kd); 284 if (kd->pmfd >= 0) 285 error |= close(kd->pmfd); 286 if (kd->vmfd >= 0) 287 error |= close(kd->vmfd); 288 if (kd->nlfd >= 0) 289 error |= close(kd->nlfd); 290 if (kd->procbase != 0) 291 free((void *)kd->procbase); 292 if (kd->argbuf != 0) 293 free((void *) kd->argbuf); 294 if (kd->argspc != 0) 295 free((void *) kd->argspc); 296 if (kd->argv != 0) 297 free((void *)kd->argv); 298 if (kd->pt_map != NULL) 299 free(kd->pt_map); 300 if (kd->page_map != NULL) 301 free(kd->page_map); 302 if (kd->sparse_map != MAP_FAILED) 303 munmap(kd->sparse_map, kd->pt_sparse_size); 304 free((void *)kd); 305 306 return (error); 307 } 308 309 int 310 kvm_nlist2(kvm_t *kd, struct kvm_nlist *nl) 311 { 312 313 /* 314 * If called via the public interface, permit initialization of 315 * further virtualized modules on demand. 316 */ 317 return (_kvm_nlist(kd, nl, 1)); 318 } 319 320 int 321 kvm_nlist(kvm_t *kd, struct nlist *nl) 322 { 323 struct kvm_nlist *kl; 324 int count, i, nfail; 325 326 /* 327 * Avoid reporting truncated addresses by failing for non-native 328 * cores. 329 */ 330 if (!kvm_native(kd)) { 331 _kvm_err(kd, kd->program, "kvm_nlist of non-native vmcore"); 332 return (-1); 333 } 334 335 for (count = 0; nl[count].n_name != NULL && nl[count].n_name[0] != '\0'; 336 count++) 337 ; 338 if (count == 0) 339 return (0); 340 kl = calloc(count + 1, sizeof(*kl)); 341 for (i = 0; i < count; i++) 342 kl[i].n_name = nl[i].n_name; 343 nfail = kvm_nlist2(kd, kl); 344 for (i = 0; i < count; i++) { 345 nl[i].n_type = kl[i].n_type; 346 nl[i].n_other = 0; 347 nl[i].n_desc = 0; 348 nl[i].n_value = kl[i].n_value; 349 } 350 return (nfail); 351 } 352 353 ssize_t 354 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) 355 { 356 357 return (kvm_read2(kd, kva, buf, len)); 358 } 359 360 ssize_t 361 kvm_read2(kvm_t *kd, kvaddr_t kva, void *buf, size_t len) 362 { 363 int cc; 364 ssize_t cr; 365 off_t pa; 366 char *cp; 367 368 if (ISALIVE(kd)) { 369 /* 370 * We're using /dev/kmem. Just read straight from the 371 * device and let the active kernel do the address translation. 372 */ 373 errno = 0; 374 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 375 _kvm_err(kd, 0, "invalid address (0x%jx)", 376 (uintmax_t)kva); 377 return (-1); 378 } 379 cr = read(kd->vmfd, buf, len); 380 if (cr < 0) { 381 _kvm_syserr(kd, 0, "kvm_read"); 382 return (-1); 383 } else if (cr < (ssize_t)len) 384 _kvm_err(kd, kd->program, "short read"); 385 return (cr); 386 } 387 388 cp = buf; 389 while (len > 0) { 390 cc = kd->arch->ka_kvatop(kd, kva, &pa); 391 if (cc == 0) 392 return (-1); 393 if (cc > (ssize_t)len) 394 cc = len; 395 errno = 0; 396 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { 397 _kvm_syserr(kd, 0, _PATH_MEM); 398 break; 399 } 400 cr = read(kd->pmfd, cp, cc); 401 if (cr < 0) { 402 _kvm_syserr(kd, kd->program, "kvm_read"); 403 break; 404 } 405 /* 406 * If ka_kvatop returns a bogus value or our core file is 407 * truncated, we might wind up seeking beyond the end of the 408 * core file in which case the read will return 0 (EOF). 409 */ 410 if (cr == 0) 411 break; 412 cp += cr; 413 kva += cr; 414 len -= cr; 415 } 416 417 return (cp - (char *)buf); 418 } 419 420 ssize_t 421 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len) 422 { 423 int cc; 424 ssize_t cw; 425 off_t pa; 426 const char *cp; 427 428 if (!ISALIVE(kd) && !kd->writable) { 429 _kvm_err(kd, kd->program, 430 "kvm_write not implemented for dead kernels"); 431 return (-1); 432 } 433 434 if (ISALIVE(kd)) { 435 /* 436 * Just like kvm_read, only we write. 437 */ 438 errno = 0; 439 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 440 _kvm_err(kd, 0, "invalid address (%lx)", kva); 441 return (-1); 442 } 443 cc = write(kd->vmfd, buf, len); 444 if (cc < 0) { 445 _kvm_syserr(kd, 0, "kvm_write"); 446 return (-1); 447 } else if ((size_t)cc < len) 448 _kvm_err(kd, kd->program, "short write"); 449 return (cc); 450 } 451 452 cp = buf; 453 while (len > 0) { 454 cc = kd->arch->ka_kvatop(kd, kva, &pa); 455 if (cc == 0) 456 return (-1); 457 if (cc > (ssize_t)len) 458 cc = len; 459 errno = 0; 460 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { 461 _kvm_syserr(kd, 0, _PATH_MEM); 462 break; 463 } 464 cw = write(kd->pmfd, cp, cc); 465 if (cw < 0) { 466 _kvm_syserr(kd, kd->program, "kvm_write"); 467 break; 468 } 469 /* 470 * If ka_kvatop returns a bogus value or our core file is 471 * truncated, we might wind up seeking beyond the end of the 472 * core file in which case the read will return 0 (EOF). 473 */ 474 if (cw == 0) 475 break; 476 cp += cw; 477 kva += cw; 478 len -= cw; 479 } 480 481 return (cp - (const char *)buf); 482 } 483 484 int 485 kvm_native(kvm_t *kd) 486 { 487 488 if (ISALIVE(kd)) 489 return (1); 490 return (kd->arch->ka_native(kd)); 491 } 492 493 int 494 kvm_walk_pages(kvm_t *kd, kvm_walk_pages_cb_t *cb, void *closure) 495 { 496 497 if (kd->arch->ka_walk_pages == NULL) 498 return (0); 499 500 return (kd->arch->ka_walk_pages(kd, cb, closure)); 501 } 502