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 65SET_DECLARE(kvm_arch, struct kvm_arch); 66 67static char _kd_is_null[] = ""; 68 69char * 70kvm_geterr(kvm_t *kd) 71{ 72 73 if (kd == NULL) 74 return (_kd_is_null); 75 return (kd->errbuf); 76} 77 78static 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 114static 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); 216failed: 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 226kvm_t * 227kvm_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 241kvm_t * 242kvm_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 257kvm_t * 258kvm_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 273int 274kvm_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->dpcpu_initialized != 0) 299 free(kd->dpcpu_off); 300 if (kd->pt_map != NULL) 301 free(kd->pt_map); 302 if (kd->page_map != NULL) 303 free(kd->page_map); 304 if (kd->sparse_map != MAP_FAILED) 305 munmap(kd->sparse_map, kd->pt_sparse_size); 306 free((void *)kd); 307 308 return (error); 309} 310 311int 312kvm_nlist2(kvm_t *kd, struct kvm_nlist *nl) 313{ 314 315 /* 316 * If called via the public interface, permit initialization of 317 * further virtualized modules on demand. 318 */ 319 return (_kvm_nlist(kd, nl, 1)); 320} 321 322int 323kvm_nlist(kvm_t *kd, struct nlist *nl) 324{ 325 struct kvm_nlist *kl; 326 int count, i, nfail; 327 328 /* 329 * Avoid reporting truncated addresses by failing for non-native 330 * cores. 331 */ 332 if (!kvm_native(kd)) { 333 _kvm_err(kd, kd->program, "kvm_nlist of non-native vmcore"); 334 return (-1); 335 } 336 337 for (count = 0; nl[count].n_name != NULL && nl[count].n_name[0] != '\0'; 338 count++) 339 ; 340 if (count == 0) 341 return (0); 342 kl = calloc(count + 1, sizeof(*kl)); 343 if (kl == NULL) { 344 _kvm_err(kd, kd->program, "cannot allocate memory"); 345 return (-1); 346 } 347 for (i = 0; i < count; i++) 348 kl[i].n_name = nl[i].n_name; 349 nfail = kvm_nlist2(kd, kl); 350 for (i = 0; i < count; i++) { 351 nl[i].n_type = kl[i].n_type; 352 nl[i].n_other = 0; 353 nl[i].n_desc = 0; 354 nl[i].n_value = kl[i].n_value; 355 } 356 free(kl); 357 return (nfail); 358} 359 360ssize_t 361kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) 362{ 363 364 return (kvm_read2(kd, kva, buf, len)); 365} 366 367ssize_t 368kvm_read2(kvm_t *kd, kvaddr_t kva, void *buf, size_t len) 369{ 370 int cc; 371 ssize_t cr; 372 off_t pa; 373 char *cp; 374 375 if (ISALIVE(kd)) { 376 /* 377 * We're using /dev/kmem. Just read straight from the 378 * device and let the active kernel do the address translation. 379 */ 380 errno = 0; 381 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 382 _kvm_err(kd, 0, "invalid address (0x%jx)", 383 (uintmax_t)kva); 384 return (-1); 385 } 386 cr = read(kd->vmfd, buf, len); 387 if (cr < 0) { 388 _kvm_syserr(kd, 0, "kvm_read"); 389 return (-1); 390 } else if (cr < (ssize_t)len) 391 _kvm_err(kd, kd->program, "short read"); 392 return (cr); 393 } 394 395 cp = buf; 396 while (len > 0) { 397 cc = kd->arch->ka_kvatop(kd, kva, &pa); 398 if (cc == 0) 399 return (-1); 400 if (cc > (ssize_t)len) 401 cc = len; 402 errno = 0; 403 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { 404 _kvm_syserr(kd, 0, _PATH_MEM); 405 break; 406 } 407 cr = read(kd->pmfd, cp, cc); 408 if (cr < 0) { 409 _kvm_syserr(kd, kd->program, "kvm_read"); 410 break; 411 } 412 /* 413 * If ka_kvatop returns a bogus value or our core file is 414 * truncated, we might wind up seeking beyond the end of the 415 * core file in which case the read will return 0 (EOF). 416 */ 417 if (cr == 0) 418 break; 419 cp += cr; 420 kva += cr; 421 len -= cr; 422 } 423 424 return (cp - (char *)buf); 425} 426 427ssize_t 428kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len) 429{ 430 int cc; 431 ssize_t cw; 432 off_t pa; 433 const char *cp; 434 435 if (!ISALIVE(kd) && !kd->writable) { 436 _kvm_err(kd, kd->program, 437 "kvm_write not implemented for dead kernels"); 438 return (-1); 439 } 440 441 if (ISALIVE(kd)) { 442 /* 443 * Just like kvm_read, only we write. 444 */ 445 errno = 0; 446 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 447 _kvm_err(kd, 0, "invalid address (%lx)", kva); 448 return (-1); 449 } 450 cc = write(kd->vmfd, buf, len); 451 if (cc < 0) { 452 _kvm_syserr(kd, 0, "kvm_write"); 453 return (-1); 454 } else if ((size_t)cc < len) 455 _kvm_err(kd, kd->program, "short write"); 456 return (cc); 457 } 458 459 cp = buf; 460 while (len > 0) { 461 cc = kd->arch->ka_kvatop(kd, kva, &pa); 462 if (cc == 0) 463 return (-1); 464 if (cc > (ssize_t)len) 465 cc = len; 466 errno = 0; 467 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { 468 _kvm_syserr(kd, 0, _PATH_MEM); 469 break; 470 } 471 cw = write(kd->pmfd, cp, cc); 472 if (cw < 0) { 473 _kvm_syserr(kd, kd->program, "kvm_write"); 474 break; 475 } 476 /* 477 * If ka_kvatop returns a bogus value or our core file is 478 * truncated, we might wind up seeking beyond the end of the 479 * core file in which case the read will return 0 (EOF). 480 */ 481 if (cw == 0) 482 break; 483 cp += cw; 484 kva += cw; 485 len -= cw; 486 } 487 488 return (cp - (const char *)buf); 489} 490 491int 492kvm_native(kvm_t *kd) 493{ 494 495 if (ISALIVE(kd)) 496 return (1); 497 return (kd->arch->ka_native(kd)); 498} 499 500int 501kvm_walk_pages(kvm_t *kd, kvm_walk_pages_cb_t *cb, void *closure) 502{ 503 504 if (kd->arch->ka_walk_pages == NULL) 505 return (0); 506 507 return (kd->arch->ka_walk_pages(kd, cb, closure)); 508} 509