1 /*- 2 * Copyright (c) 1989, 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software developed by the Computer Systems 6 * Engineering group at Lawrence Berkeley Laboratory under DARPA contract 7 * BG 91-66 and contributed to Berkeley. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)kvm.c 8.2 (Berkeley) 2/13/94"; 40 #endif 41 #endif /* LIBC_SCCS and not lint */ 42 43 #include <sys/param.h> 44 45 #define _WANT_VNET 46 47 #include <sys/user.h> 48 #include <sys/proc.h> 49 #include <sys/ioctl.h> 50 #include <sys/stat.h> 51 #include <sys/sysctl.h> 52 #include <sys/linker.h> 53 #include <sys/pcpu.h> 54 55 #include <net/vnet.h> 56 57 #include <vm/vm.h> 58 #include <vm/vm_param.h> 59 60 #include <machine/vmparam.h> 61 62 #include <ctype.h> 63 #include <fcntl.h> 64 #include <kvm.h> 65 #include <limits.h> 66 #include <nlist.h> 67 #include <paths.h> 68 #include <stdio.h> 69 #include <stdlib.h> 70 #include <string.h> 71 #include <strings.h> 72 #include <unistd.h> 73 74 #include "kvm_private.h" 75 76 /* from src/lib/libc/gen/nlist.c */ 77 int __fdnlist(int, struct nlist *); 78 79 char * 80 kvm_geterr(kvm_t *kd) 81 { 82 return (kd->errbuf); 83 } 84 85 #include <stdarg.h> 86 87 /* 88 * Report an error using printf style arguments. "program" is kd->program 89 * on hard errors, and 0 on soft errors, so that under sun error emulation, 90 * only hard errors are printed out (otherwise, programs like gdb will 91 * generate tons of error messages when trying to access bogus pointers). 92 */ 93 void 94 _kvm_err(kvm_t *kd, const char *program, const char *fmt, ...) 95 { 96 va_list ap; 97 98 va_start(ap, fmt); 99 if (program != NULL) { 100 (void)fprintf(stderr, "%s: ", program); 101 (void)vfprintf(stderr, fmt, ap); 102 (void)fputc('\n', stderr); 103 } else 104 (void)vsnprintf(kd->errbuf, 105 sizeof(kd->errbuf), fmt, ap); 106 107 va_end(ap); 108 } 109 110 void 111 _kvm_syserr(kvm_t *kd, const char *program, const char *fmt, ...) 112 { 113 va_list ap; 114 int n; 115 116 va_start(ap, fmt); 117 if (program != NULL) { 118 (void)fprintf(stderr, "%s: ", program); 119 (void)vfprintf(stderr, fmt, ap); 120 (void)fprintf(stderr, ": %s\n", strerror(errno)); 121 } else { 122 char *cp = kd->errbuf; 123 124 (void)vsnprintf(cp, sizeof(kd->errbuf), fmt, ap); 125 n = strlen(cp); 126 (void)snprintf(&cp[n], sizeof(kd->errbuf) - n, ": %s", 127 strerror(errno)); 128 } 129 va_end(ap); 130 } 131 132 void * 133 _kvm_malloc(kvm_t *kd, size_t n) 134 { 135 void *p; 136 137 if ((p = calloc(n, sizeof(char))) == NULL) 138 _kvm_err(kd, kd->program, "can't allocate %zu bytes: %s", 139 n, strerror(errno)); 140 return (p); 141 } 142 143 static kvm_t * 144 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout) 145 { 146 struct stat st; 147 148 kd->vmfd = -1; 149 kd->pmfd = -1; 150 kd->nlfd = -1; 151 kd->vmst = 0; 152 kd->procbase = 0; 153 kd->argspc = 0; 154 kd->argv = 0; 155 156 if (uf == 0) 157 uf = getbootfile(); 158 else if (strlen(uf) >= MAXPATHLEN) { 159 _kvm_err(kd, kd->program, "exec file name too long"); 160 goto failed; 161 } 162 if (flag & ~O_RDWR) { 163 _kvm_err(kd, kd->program, "bad flags arg"); 164 goto failed; 165 } 166 if (mf == 0) 167 mf = _PATH_MEM; 168 169 if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) { 170 _kvm_syserr(kd, kd->program, "%s", mf); 171 goto failed; 172 } 173 if (fstat(kd->pmfd, &st) < 0) { 174 _kvm_syserr(kd, kd->program, "%s", mf); 175 goto failed; 176 } 177 if (S_ISREG(st.st_mode) && st.st_size <= 0) { 178 errno = EINVAL; 179 _kvm_syserr(kd, kd->program, "empty file"); 180 goto failed; 181 } 182 if (S_ISCHR(st.st_mode)) { 183 /* 184 * If this is a character special device, then check that 185 * it's /dev/mem. If so, open kmem too. (Maybe we should 186 * make it work for either /dev/mem or /dev/kmem -- in either 187 * case you're working with a live kernel.) 188 */ 189 if (strcmp(mf, _PATH_DEVNULL) == 0) { 190 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY | O_CLOEXEC); 191 return (kd); 192 } else if (strcmp(mf, _PATH_MEM) == 0) { 193 if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) < 194 0) { 195 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); 196 goto failed; 197 } 198 return (kd); 199 } 200 } 201 /* 202 * This is a crash dump. 203 * Initialize the virtual address translation machinery, 204 * but first setup the namelist fd. 205 */ 206 if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) { 207 _kvm_syserr(kd, kd->program, "%s", uf); 208 goto failed; 209 } 210 if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0) 211 kd->rawdump = 1; 212 if (_kvm_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 != 0) 220 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX); 221 (void)kvm_close(kd); 222 return (0); 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 (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX); 233 return (0); 234 } 235 kd->program = 0; 236 return (_kvm_open(kd, uf, mf, flag, errout)); 237 } 238 239 kvm_t * 240 kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag, 241 const char *errstr) 242 { 243 kvm_t *kd; 244 245 if ((kd = calloc(1, sizeof(*kd))) == NULL) { 246 if (errstr != NULL) 247 (void)fprintf(stderr, "%s: %s\n", 248 errstr, strerror(errno)); 249 return (0); 250 } 251 kd->program = errstr; 252 return (_kvm_open(kd, uf, mf, flag, NULL)); 253 } 254 255 int 256 kvm_close(kvm_t *kd) 257 { 258 int error = 0; 259 260 if (kd->pmfd >= 0) 261 error |= close(kd->pmfd); 262 if (kd->vmfd >= 0) 263 error |= close(kd->vmfd); 264 if (kd->nlfd >= 0) 265 error |= close(kd->nlfd); 266 if (kd->vmst) 267 _kvm_freevtop(kd); 268 if (kd->procbase != 0) 269 free((void *)kd->procbase); 270 if (kd->argbuf != 0) 271 free((void *) kd->argbuf); 272 if (kd->argspc != 0) 273 free((void *) kd->argspc); 274 if (kd->argv != 0) 275 free((void *)kd->argv); 276 free((void *)kd); 277 278 return (0); 279 } 280 281 /* 282 * Walk the list of unresolved symbols, generate a new list and prefix the 283 * symbol names, try again, and merge back what we could resolve. 284 */ 285 static int 286 kvm_fdnlist_prefix(kvm_t *kd, struct nlist *nl, int missing, const char *prefix, 287 uintptr_t (*validate_fn)(kvm_t *, uintptr_t)) 288 { 289 struct nlist *n, *np, *p; 290 char *cp, *ce; 291 const char *ccp; 292 size_t len; 293 int slen, unresolved; 294 295 /* 296 * Calculate the space we need to malloc for nlist and names. 297 * We are going to store the name twice for later lookups: once 298 * with the prefix and once the unmodified name delmited by \0. 299 */ 300 len = 0; 301 unresolved = 0; 302 for (p = nl; p->n_name && p->n_name[0]; ++p) { 303 if (p->n_type != N_UNDF) 304 continue; 305 len += sizeof(struct nlist) + strlen(prefix) + 306 2 * (strlen(p->n_name) + 1); 307 unresolved++; 308 } 309 if (unresolved == 0) 310 return (unresolved); 311 /* Add space for the terminating nlist entry. */ 312 len += sizeof(struct nlist); 313 unresolved++; 314 315 /* Alloc one chunk for (nlist, [names]) and setup pointers. */ 316 n = np = malloc(len); 317 bzero(n, len); 318 if (n == NULL) 319 return (missing); 320 cp = ce = (char *)np; 321 cp += unresolved * sizeof(struct nlist); 322 ce += len; 323 324 /* Generate shortened nlist with special prefix. */ 325 unresolved = 0; 326 for (p = nl; p->n_name && p->n_name[0]; ++p) { 327 if (p->n_type != N_UNDF) 328 continue; 329 bcopy(p, np, sizeof(struct nlist)); 330 /* Save the new\0orig. name so we can later match it again. */ 331 slen = snprintf(cp, ce - cp, "%s%s%c%s", prefix, 332 (prefix[0] != '\0' && p->n_name[0] == '_') ? 333 (p->n_name + 1) : p->n_name, '\0', p->n_name); 334 if (slen < 0 || slen >= ce - cp) 335 continue; 336 np->n_name = cp; 337 cp += slen + 1; 338 np++; 339 unresolved++; 340 } 341 342 /* Do lookup on the reduced list. */ 343 np = n; 344 unresolved = __fdnlist(kd->nlfd, np); 345 346 /* Check if we could resolve further symbols and update the list. */ 347 if (unresolved >= 0 && unresolved < missing) { 348 /* Find the first freshly resolved entry. */ 349 for (; np->n_name && np->n_name[0]; np++) 350 if (np->n_type != N_UNDF) 351 break; 352 /* 353 * The lists are both in the same order, 354 * so we can walk them in parallel. 355 */ 356 for (p = nl; np->n_name && np->n_name[0] && 357 p->n_name && p->n_name[0]; ++p) { 358 if (p->n_type != N_UNDF) 359 continue; 360 /* Skip expanded name and compare to orig. one. */ 361 ccp = np->n_name + strlen(np->n_name) + 1; 362 if (strcmp(ccp, p->n_name) != 0) 363 continue; 364 /* Update nlist with new, translated results. */ 365 p->n_type = np->n_type; 366 p->n_other = np->n_other; 367 p->n_desc = np->n_desc; 368 if (validate_fn) 369 p->n_value = (*validate_fn)(kd, np->n_value); 370 else 371 p->n_value = np->n_value; 372 missing--; 373 /* Find next freshly resolved entry. */ 374 for (np++; np->n_name && np->n_name[0]; np++) 375 if (np->n_type != N_UNDF) 376 break; 377 } 378 } 379 /* We could assert missing = unresolved here. */ 380 381 free(n); 382 return (unresolved); 383 } 384 385 int 386 _kvm_nlist(kvm_t *kd, struct nlist *nl, int initialize) 387 { 388 struct nlist *p; 389 int nvalid; 390 struct kld_sym_lookup lookup; 391 int error; 392 const char *prefix = ""; 393 char symname[1024]; /* XXX-BZ symbol name length limit? */ 394 int tried_vnet, tried_dpcpu; 395 396 /* 397 * If we can't use the kld symbol lookup, revert to the 398 * slow library call. 399 */ 400 if (!ISALIVE(kd)) { 401 error = __fdnlist(kd->nlfd, nl); 402 if (error <= 0) /* Hard error or success. */ 403 return (error); 404 405 if (_kvm_vnet_initialized(kd, initialize)) 406 error = kvm_fdnlist_prefix(kd, nl, error, 407 VNET_SYMPREFIX, _kvm_vnet_validaddr); 408 409 if (error > 0 && _kvm_dpcpu_initialized(kd, initialize)) 410 error = kvm_fdnlist_prefix(kd, nl, error, 411 DPCPU_SYMPREFIX, _kvm_dpcpu_validaddr); 412 413 return (error); 414 } 415 416 /* 417 * We can use the kld lookup syscall. Go through each nlist entry 418 * and look it up with a kldsym(2) syscall. 419 */ 420 nvalid = 0; 421 tried_vnet = 0; 422 tried_dpcpu = 0; 423 again: 424 for (p = nl; p->n_name && p->n_name[0]; ++p) { 425 if (p->n_type != N_UNDF) 426 continue; 427 428 lookup.version = sizeof(lookup); 429 lookup.symvalue = 0; 430 lookup.symsize = 0; 431 432 error = snprintf(symname, sizeof(symname), "%s%s", prefix, 433 (prefix[0] != '\0' && p->n_name[0] == '_') ? 434 (p->n_name + 1) : p->n_name); 435 if (error < 0 || error >= (int)sizeof(symname)) 436 continue; 437 lookup.symname = symname; 438 if (lookup.symname[0] == '_') 439 lookup.symname++; 440 441 if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) { 442 p->n_type = N_TEXT; 443 p->n_other = 0; 444 p->n_desc = 0; 445 if (_kvm_vnet_initialized(kd, initialize) && 446 strcmp(prefix, VNET_SYMPREFIX) == 0) 447 p->n_value = 448 _kvm_vnet_validaddr(kd, lookup.symvalue); 449 else if (_kvm_dpcpu_initialized(kd, initialize) && 450 strcmp(prefix, DPCPU_SYMPREFIX) == 0) 451 p->n_value = 452 _kvm_dpcpu_validaddr(kd, lookup.symvalue); 453 else 454 p->n_value = lookup.symvalue; 455 ++nvalid; 456 /* lookup.symsize */ 457 } 458 } 459 460 /* 461 * Check the number of entries that weren't found. If they exist, 462 * try again with a prefix for virtualized or DPCPU symbol names. 463 */ 464 error = ((p - nl) - nvalid); 465 if (error && _kvm_vnet_initialized(kd, initialize) && !tried_vnet) { 466 tried_vnet = 1; 467 prefix = VNET_SYMPREFIX; 468 goto again; 469 } 470 if (error && _kvm_dpcpu_initialized(kd, initialize) && !tried_dpcpu) { 471 tried_dpcpu = 1; 472 prefix = DPCPU_SYMPREFIX; 473 goto again; 474 } 475 476 /* 477 * Return the number of entries that weren't found. If they exist, 478 * also fill internal error buffer. 479 */ 480 error = ((p - nl) - nvalid); 481 if (error) 482 _kvm_syserr(kd, kd->program, "kvm_nlist"); 483 return (error); 484 } 485 486 int 487 kvm_nlist(kvm_t *kd, struct nlist *nl) 488 { 489 490 /* 491 * If called via the public interface, permit intialization of 492 * further virtualized modules on demand. 493 */ 494 return (_kvm_nlist(kd, nl, 1)); 495 } 496 497 ssize_t 498 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) 499 { 500 int cc; 501 ssize_t cr; 502 off_t pa; 503 char *cp; 504 505 if (ISALIVE(kd)) { 506 /* 507 * We're using /dev/kmem. Just read straight from the 508 * device and let the active kernel do the address translation. 509 */ 510 errno = 0; 511 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 512 _kvm_err(kd, 0, "invalid address (%lx)", kva); 513 return (-1); 514 } 515 cr = read(kd->vmfd, buf, len); 516 if (cr < 0) { 517 _kvm_syserr(kd, 0, "kvm_read"); 518 return (-1); 519 } else if (cr < (ssize_t)len) 520 _kvm_err(kd, kd->program, "short read"); 521 return (cr); 522 } 523 524 cp = buf; 525 while (len > 0) { 526 cc = _kvm_kvatop(kd, kva, &pa); 527 if (cc == 0) 528 return (-1); 529 if (cc > (ssize_t)len) 530 cc = len; 531 errno = 0; 532 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { 533 _kvm_syserr(kd, 0, _PATH_MEM); 534 break; 535 } 536 cr = read(kd->pmfd, cp, cc); 537 if (cr < 0) { 538 _kvm_syserr(kd, kd->program, "kvm_read"); 539 break; 540 } 541 /* 542 * If kvm_kvatop returns a bogus value or our core file is 543 * truncated, we might wind up seeking beyond the end of the 544 * core file in which case the read will return 0 (EOF). 545 */ 546 if (cr == 0) 547 break; 548 cp += cr; 549 kva += cr; 550 len -= cr; 551 } 552 553 return (cp - (char *)buf); 554 } 555 556 ssize_t 557 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len) 558 { 559 int cc; 560 561 if (ISALIVE(kd)) { 562 /* 563 * Just like kvm_read, only we write. 564 */ 565 errno = 0; 566 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 567 _kvm_err(kd, 0, "invalid address (%lx)", kva); 568 return (-1); 569 } 570 cc = write(kd->vmfd, buf, len); 571 if (cc < 0) { 572 _kvm_syserr(kd, 0, "kvm_write"); 573 return (-1); 574 } else if ((size_t)cc < len) 575 _kvm_err(kd, kd->program, "short write"); 576 return (cc); 577 } else { 578 _kvm_err(kd, kd->program, 579 "kvm_write not implemented for dead kernels"); 580 return (-1); 581 } 582 /* NOTREACHED */ 583 } 584