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 #ifndef CROSS_LIBKVM 77 78 /* from src/lib/libc/gen/nlist.c */ 79 int __fdnlist(int, struct nlist *); 80 81 #define kvm_fdnlist __fdnlist 82 83 #else 84 85 #include <proc_service.h> 86 87 static int 88 kvm_fdnlist(int fd, struct nlist *list) 89 { 90 psaddr_t addr; 91 ps_err_e pserr; 92 int nfail; 93 94 nfail = 0; 95 while (list->n_name != NULL && list->n_name[0] != '\0') { 96 list->n_other = 0; 97 list->n_desc = 0; 98 pserr = ps_pglobal_lookup(NULL, NULL, list->n_name, &addr); 99 if (pserr != PS_OK) { 100 nfail++; 101 list->n_value = 0; 102 list->n_type = 0; 103 } else { 104 list->n_value = addr; 105 list->n_type = N_DATA | N_EXT; 106 } 107 list++; 108 } 109 return (nfail); 110 } 111 112 #endif /* CROSS_LIBKVM */ 113 114 char * 115 kvm_geterr(kvm_t *kd) 116 { 117 return (kd->errbuf); 118 } 119 120 #include <stdarg.h> 121 122 /* 123 * Report an error using printf style arguments. "program" is kd->program 124 * on hard errors, and 0 on soft errors, so that under sun error emulation, 125 * only hard errors are printed out (otherwise, programs like gdb will 126 * generate tons of error messages when trying to access bogus pointers). 127 */ 128 void 129 _kvm_err(kvm_t *kd, const char *program, const char *fmt, ...) 130 { 131 va_list ap; 132 133 va_start(ap, fmt); 134 if (program != NULL) { 135 (void)fprintf(stderr, "%s: ", program); 136 (void)vfprintf(stderr, fmt, ap); 137 (void)fputc('\n', stderr); 138 } else 139 (void)vsnprintf(kd->errbuf, 140 sizeof(kd->errbuf), fmt, ap); 141 142 va_end(ap); 143 } 144 145 void 146 _kvm_syserr(kvm_t *kd, const char *program, const char *fmt, ...) 147 { 148 va_list ap; 149 int n; 150 151 va_start(ap, fmt); 152 if (program != NULL) { 153 (void)fprintf(stderr, "%s: ", program); 154 (void)vfprintf(stderr, fmt, ap); 155 (void)fprintf(stderr, ": %s\n", strerror(errno)); 156 } else { 157 char *cp = kd->errbuf; 158 159 (void)vsnprintf(cp, sizeof(kd->errbuf), fmt, ap); 160 n = strlen(cp); 161 (void)snprintf(&cp[n], sizeof(kd->errbuf) - n, ": %s", 162 strerror(errno)); 163 } 164 va_end(ap); 165 } 166 167 void * 168 _kvm_malloc(kvm_t *kd, size_t n) 169 { 170 void *p; 171 172 if ((p = calloc(n, sizeof(char))) == NULL) 173 _kvm_err(kd, kd->program, "can't allocate %zu bytes: %s", 174 n, strerror(errno)); 175 return (p); 176 } 177 178 static kvm_t * 179 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout) 180 { 181 struct stat st; 182 183 kd->vmfd = -1; 184 kd->pmfd = -1; 185 kd->nlfd = -1; 186 kd->vmst = 0; 187 kd->procbase = 0; 188 kd->argspc = 0; 189 kd->argv = 0; 190 191 if (uf == 0) 192 uf = getbootfile(); 193 else if (strlen(uf) >= MAXPATHLEN) { 194 _kvm_err(kd, kd->program, "exec file name too long"); 195 goto failed; 196 } 197 if (flag & ~O_RDWR) { 198 _kvm_err(kd, kd->program, "bad flags arg"); 199 goto failed; 200 } 201 if (mf == 0) 202 mf = _PATH_MEM; 203 204 if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) { 205 _kvm_syserr(kd, kd->program, "%s", mf); 206 goto failed; 207 } 208 if (fstat(kd->pmfd, &st) < 0) { 209 _kvm_syserr(kd, kd->program, "%s", mf); 210 goto failed; 211 } 212 if (S_ISREG(st.st_mode) && st.st_size <= 0) { 213 errno = EINVAL; 214 _kvm_syserr(kd, kd->program, "empty file"); 215 goto failed; 216 } 217 if (S_ISCHR(st.st_mode)) { 218 /* 219 * If this is a character special device, then check that 220 * it's /dev/mem. If so, open kmem too. (Maybe we should 221 * make it work for either /dev/mem or /dev/kmem -- in either 222 * case you're working with a live kernel.) 223 */ 224 if (strcmp(mf, _PATH_DEVNULL) == 0) { 225 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY | O_CLOEXEC); 226 return (kd); 227 } else if (strcmp(mf, _PATH_MEM) == 0) { 228 if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) < 229 0) { 230 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); 231 goto failed; 232 } 233 return (kd); 234 } 235 } 236 /* 237 * This is a crash dump. 238 * Initialize the virtual address translation machinery, 239 * but first setup the namelist fd. 240 */ 241 if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) { 242 _kvm_syserr(kd, kd->program, "%s", uf); 243 goto failed; 244 } 245 if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0) 246 kd->rawdump = 1; 247 if (_kvm_initvtop(kd) < 0) 248 goto failed; 249 return (kd); 250 failed: 251 /* 252 * Copy out the error if doing sane error semantics. 253 */ 254 if (errout != 0) 255 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX); 256 (void)kvm_close(kd); 257 return (0); 258 } 259 260 kvm_t * 261 kvm_openfiles(const char *uf, const char *mf, const char *sf __unused, int flag, 262 char *errout) 263 { 264 kvm_t *kd; 265 266 if ((kd = calloc(1, sizeof(*kd))) == NULL) { 267 (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX); 268 return (0); 269 } 270 kd->program = 0; 271 return (_kvm_open(kd, uf, mf, flag, errout)); 272 } 273 274 kvm_t * 275 kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag, 276 const char *errstr) 277 { 278 kvm_t *kd; 279 280 if ((kd = calloc(1, sizeof(*kd))) == NULL) { 281 if (errstr != NULL) 282 (void)fprintf(stderr, "%s: %s\n", 283 errstr, strerror(errno)); 284 return (0); 285 } 286 kd->program = errstr; 287 return (_kvm_open(kd, uf, mf, flag, NULL)); 288 } 289 290 int 291 kvm_close(kvm_t *kd) 292 { 293 int error = 0; 294 295 if (kd->pmfd >= 0) 296 error |= close(kd->pmfd); 297 if (kd->vmfd >= 0) 298 error |= close(kd->vmfd); 299 if (kd->nlfd >= 0) 300 error |= close(kd->nlfd); 301 if (kd->vmst) 302 _kvm_freevtop(kd); 303 if (kd->procbase != 0) 304 free((void *)kd->procbase); 305 if (kd->argbuf != 0) 306 free((void *) kd->argbuf); 307 if (kd->argspc != 0) 308 free((void *) kd->argspc); 309 if (kd->argv != 0) 310 free((void *)kd->argv); 311 free((void *)kd); 312 313 return (0); 314 } 315 316 /* 317 * Walk the list of unresolved symbols, generate a new list and prefix the 318 * symbol names, try again, and merge back what we could resolve. 319 */ 320 static int 321 kvm_fdnlist_prefix(kvm_t *kd, struct nlist *nl, int missing, const char *prefix, 322 uintptr_t (*validate_fn)(kvm_t *, uintptr_t)) 323 { 324 struct nlist *n, *np, *p; 325 char *cp, *ce; 326 const char *ccp; 327 size_t len; 328 int slen, unresolved; 329 330 /* 331 * Calculate the space we need to malloc for nlist and names. 332 * We are going to store the name twice for later lookups: once 333 * with the prefix and once the unmodified name delmited by \0. 334 */ 335 len = 0; 336 unresolved = 0; 337 for (p = nl; p->n_name && p->n_name[0]; ++p) { 338 if (p->n_type != N_UNDF) 339 continue; 340 len += sizeof(struct nlist) + strlen(prefix) + 341 2 * (strlen(p->n_name) + 1); 342 unresolved++; 343 } 344 if (unresolved == 0) 345 return (unresolved); 346 /* Add space for the terminating nlist entry. */ 347 len += sizeof(struct nlist); 348 unresolved++; 349 350 /* Alloc one chunk for (nlist, [names]) and setup pointers. */ 351 n = np = malloc(len); 352 bzero(n, len); 353 if (n == NULL) 354 return (missing); 355 cp = ce = (char *)np; 356 cp += unresolved * sizeof(struct nlist); 357 ce += len; 358 359 /* Generate shortened nlist with special prefix. */ 360 unresolved = 0; 361 for (p = nl; p->n_name && p->n_name[0]; ++p) { 362 if (p->n_type != N_UNDF) 363 continue; 364 bcopy(p, np, sizeof(struct nlist)); 365 /* Save the new\0orig. name so we can later match it again. */ 366 slen = snprintf(cp, ce - cp, "%s%s%c%s", prefix, 367 (prefix[0] != '\0' && p->n_name[0] == '_') ? 368 (p->n_name + 1) : p->n_name, '\0', p->n_name); 369 if (slen < 0 || slen >= ce - cp) 370 continue; 371 np->n_name = cp; 372 cp += slen + 1; 373 np++; 374 unresolved++; 375 } 376 377 /* Do lookup on the reduced list. */ 378 np = n; 379 unresolved = kvm_fdnlist(kd->nlfd, np); 380 381 /* Check if we could resolve further symbols and update the list. */ 382 if (unresolved >= 0 && unresolved < missing) { 383 /* Find the first freshly resolved entry. */ 384 for (; np->n_name && np->n_name[0]; np++) 385 if (np->n_type != N_UNDF) 386 break; 387 /* 388 * The lists are both in the same order, 389 * so we can walk them in parallel. 390 */ 391 for (p = nl; np->n_name && np->n_name[0] && 392 p->n_name && p->n_name[0]; ++p) { 393 if (p->n_type != N_UNDF) 394 continue; 395 /* Skip expanded name and compare to orig. one. */ 396 ccp = np->n_name + strlen(np->n_name) + 1; 397 if (strcmp(ccp, p->n_name) != 0) 398 continue; 399 /* Update nlist with new, translated results. */ 400 p->n_type = np->n_type; 401 p->n_other = np->n_other; 402 p->n_desc = np->n_desc; 403 if (validate_fn) 404 p->n_value = (*validate_fn)(kd, np->n_value); 405 else 406 p->n_value = np->n_value; 407 missing--; 408 /* Find next freshly resolved entry. */ 409 for (np++; np->n_name && np->n_name[0]; np++) 410 if (np->n_type != N_UNDF) 411 break; 412 } 413 } 414 /* We could assert missing = unresolved here. */ 415 416 free(n); 417 return (unresolved); 418 } 419 420 int 421 _kvm_nlist(kvm_t *kd, struct nlist *nl, int initialize) 422 { 423 struct nlist *p; 424 int nvalid; 425 struct kld_sym_lookup lookup; 426 int error; 427 const char *prefix = ""; 428 char symname[1024]; /* XXX-BZ symbol name length limit? */ 429 int tried_vnet, tried_dpcpu; 430 431 /* 432 * If we can't use the kld symbol lookup, revert to the 433 * slow library call. 434 */ 435 if (!ISALIVE(kd)) { 436 error = kvm_fdnlist(kd->nlfd, nl); 437 if (error <= 0) /* Hard error or success. */ 438 return (error); 439 440 if (_kvm_vnet_initialized(kd, initialize)) 441 error = kvm_fdnlist_prefix(kd, nl, error, 442 VNET_SYMPREFIX, _kvm_vnet_validaddr); 443 444 if (error > 0 && _kvm_dpcpu_initialized(kd, initialize)) 445 error = kvm_fdnlist_prefix(kd, nl, error, 446 DPCPU_SYMPREFIX, _kvm_dpcpu_validaddr); 447 448 return (error); 449 } 450 451 /* 452 * We can use the kld lookup syscall. Go through each nlist entry 453 * and look it up with a kldsym(2) syscall. 454 */ 455 nvalid = 0; 456 tried_vnet = 0; 457 tried_dpcpu = 0; 458 again: 459 for (p = nl; p->n_name && p->n_name[0]; ++p) { 460 if (p->n_type != N_UNDF) 461 continue; 462 463 lookup.version = sizeof(lookup); 464 lookup.symvalue = 0; 465 lookup.symsize = 0; 466 467 error = snprintf(symname, sizeof(symname), "%s%s", prefix, 468 (prefix[0] != '\0' && p->n_name[0] == '_') ? 469 (p->n_name + 1) : p->n_name); 470 if (error < 0 || error >= (int)sizeof(symname)) 471 continue; 472 lookup.symname = symname; 473 if (lookup.symname[0] == '_') 474 lookup.symname++; 475 476 if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) { 477 p->n_type = N_TEXT; 478 p->n_other = 0; 479 p->n_desc = 0; 480 if (_kvm_vnet_initialized(kd, initialize) && 481 strcmp(prefix, VNET_SYMPREFIX) == 0) 482 p->n_value = 483 _kvm_vnet_validaddr(kd, lookup.symvalue); 484 else if (_kvm_dpcpu_initialized(kd, initialize) && 485 strcmp(prefix, DPCPU_SYMPREFIX) == 0) 486 p->n_value = 487 _kvm_dpcpu_validaddr(kd, lookup.symvalue); 488 else 489 p->n_value = lookup.symvalue; 490 ++nvalid; 491 /* lookup.symsize */ 492 } 493 } 494 495 /* 496 * Check the number of entries that weren't found. If they exist, 497 * try again with a prefix for virtualized or DPCPU symbol names. 498 */ 499 error = ((p - nl) - nvalid); 500 if (error && _kvm_vnet_initialized(kd, initialize) && !tried_vnet) { 501 tried_vnet = 1; 502 prefix = VNET_SYMPREFIX; 503 goto again; 504 } 505 if (error && _kvm_dpcpu_initialized(kd, initialize) && !tried_dpcpu) { 506 tried_dpcpu = 1; 507 prefix = DPCPU_SYMPREFIX; 508 goto again; 509 } 510 511 /* 512 * Return the number of entries that weren't found. If they exist, 513 * also fill internal error buffer. 514 */ 515 error = ((p - nl) - nvalid); 516 if (error) 517 _kvm_syserr(kd, kd->program, "kvm_nlist"); 518 return (error); 519 } 520 521 int 522 kvm_nlist(kvm_t *kd, struct nlist *nl) 523 { 524 525 /* 526 * If called via the public interface, permit intialization of 527 * further virtualized modules on demand. 528 */ 529 return (_kvm_nlist(kd, nl, 1)); 530 } 531 532 ssize_t 533 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) 534 { 535 int cc; 536 ssize_t cr; 537 off_t pa; 538 char *cp; 539 540 if (ISALIVE(kd)) { 541 /* 542 * We're using /dev/kmem. Just read straight from the 543 * device and let the active kernel do the address translation. 544 */ 545 errno = 0; 546 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 547 _kvm_err(kd, 0, "invalid address (%lx)", kva); 548 return (-1); 549 } 550 cr = read(kd->vmfd, buf, len); 551 if (cr < 0) { 552 _kvm_syserr(kd, 0, "kvm_read"); 553 return (-1); 554 } else if (cr < (ssize_t)len) 555 _kvm_err(kd, kd->program, "short read"); 556 return (cr); 557 } 558 559 cp = buf; 560 while (len > 0) { 561 cc = _kvm_kvatop(kd, kva, &pa); 562 if (cc == 0) 563 return (-1); 564 if (cc > (ssize_t)len) 565 cc = len; 566 errno = 0; 567 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { 568 _kvm_syserr(kd, 0, _PATH_MEM); 569 break; 570 } 571 cr = read(kd->pmfd, cp, cc); 572 if (cr < 0) { 573 _kvm_syserr(kd, kd->program, "kvm_read"); 574 break; 575 } 576 /* 577 * If kvm_kvatop returns a bogus value or our core file is 578 * truncated, we might wind up seeking beyond the end of the 579 * core file in which case the read will return 0 (EOF). 580 */ 581 if (cr == 0) 582 break; 583 cp += cr; 584 kva += cr; 585 len -= cr; 586 } 587 588 return (cp - (char *)buf); 589 } 590 591 ssize_t 592 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len) 593 { 594 int cc; 595 596 if (ISALIVE(kd)) { 597 /* 598 * Just like kvm_read, only we write. 599 */ 600 errno = 0; 601 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 602 _kvm_err(kd, 0, "invalid address (%lx)", kva); 603 return (-1); 604 } 605 cc = write(kd->vmfd, buf, len); 606 if (cc < 0) { 607 _kvm_syserr(kd, 0, "kvm_write"); 608 return (-1); 609 } else if ((size_t)cc < len) 610 _kvm_err(kd, kd->program, "short write"); 611 return (cc); 612 } else { 613 _kvm_err(kd, kd->program, 614 "kvm_write not implemented for dead kernels"); 615 return (-1); 616 } 617 /* NOTREACHED */ 618 } 619