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 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)kvm.c 8.2 (Berkeley) 2/13/94 38 * $FreeBSD: src/lib/libkvm/kvm.c,v 1.12.2.3 2002/09/13 14:53:43 nectar Exp $ 39 * $DragonFly: src/lib/libkvm/kvm.c,v 1.8 2006/01/11 01:12:59 corecode Exp $ 40 */ 41 42 #include <sys/param.h> 43 #include <sys/user.h> 44 #include <sys/proc.h> 45 #include <sys/ioctl.h> 46 #include <sys/stat.h> 47 #include <sys/sysctl.h> 48 #include <sys/linker.h> 49 50 #include <vm/vm.h> 51 #include <vm/vm_param.h> 52 #include <vm/swap_pager.h> 53 54 #include <machine/vmparam.h> 55 56 #include <ctype.h> 57 #include <fcntl.h> 58 #include <kvm.h> 59 #include <limits.h> 60 #include <nlist.h> 61 #include <paths.h> 62 #include <stdio.h> 63 #include <stdlib.h> 64 #include <string.h> 65 #include <stdarg.h> 66 #include <unistd.h> 67 68 #include "kvm_private.h" 69 70 /* from src/lib/libc/gen/nlist.c */ 71 int __fdnlist (int, struct nlist *); 72 73 char * 74 kvm_geterr(kvm_t *kd) 75 { 76 return (kd->errbuf); 77 } 78 79 /* 80 * Report an error using printf style arguments. "program" is kd->program 81 * on hard errors, and 0 on soft errors, so that under sun error emulation, 82 * only hard errors are printed out (otherwise, programs like gdb will 83 * generate tons of error messages when trying to access bogus pointers). 84 */ 85 void 86 _kvm_err(kvm_t *kd, const char *program, const char *fmt, ...) 87 { 88 va_list ap; 89 90 va_start(ap, fmt); 91 if (program != NULL) { 92 (void)fprintf(stderr, "%s: ", program); 93 (void)vfprintf(stderr, fmt, ap); 94 (void)fputc('\n', stderr); 95 } else 96 (void)vsnprintf(kd->errbuf, 97 sizeof(kd->errbuf), (char *)fmt, ap); 98 99 va_end(ap); 100 } 101 102 void 103 _kvm_syserr(kvm_t *kd, const char *program, const char *fmt, ...) 104 { 105 va_list ap; 106 int n; 107 108 va_start(ap, fmt); 109 if (program != NULL) { 110 (void)fprintf(stderr, "%s: ", program); 111 (void)vfprintf(stderr, fmt, ap); 112 (void)fprintf(stderr, ": %s\n", strerror(errno)); 113 } else { 114 char *cp = kd->errbuf; 115 116 (void)vsnprintf(cp, sizeof(kd->errbuf), (char *)fmt, ap); 117 n = strlen(cp); 118 (void)snprintf(&cp[n], sizeof(kd->errbuf) - n, ": %s", 119 strerror(errno)); 120 } 121 va_end(ap); 122 } 123 124 void * 125 _kvm_malloc(kvm_t *kd, size_t n) 126 { 127 void *p; 128 129 if ((p = calloc(n, sizeof(char))) == NULL) 130 _kvm_err(kd, kd->program, "can't allocate %u bytes: %s", 131 n, strerror(errno)); 132 return (p); 133 } 134 135 static kvm_t * 136 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout) 137 { 138 struct stat st; 139 140 kd->vmfd = -1; 141 kd->pmfd = -1; 142 kd->nlfd = -1; 143 kd->vmst = 0; 144 kd->procbase = 0; 145 kd->argspc = 0; 146 kd->argv = 0; 147 148 if (uf == 0) 149 uf = getbootfile(); 150 else if (strlen(uf) >= MAXPATHLEN) { 151 _kvm_err(kd, kd->program, "exec file name too long"); 152 goto failed; 153 } 154 if (flag & ~O_RDWR) { 155 _kvm_err(kd, kd->program, "bad flags arg"); 156 goto failed; 157 } 158 if (mf == 0) 159 mf = _PATH_MEM; 160 161 if ((kd->pmfd = open(mf, flag, 0)) < 0) { 162 _kvm_syserr(kd, kd->program, "%s", mf); 163 goto failed; 164 } 165 if (fstat(kd->pmfd, &st) < 0) { 166 _kvm_syserr(kd, kd->program, "%s", mf); 167 goto failed; 168 } 169 if (fcntl(kd->pmfd, F_SETFD, FD_CLOEXEC) < 0) { 170 _kvm_syserr(kd, kd->program, "%s", mf); 171 goto failed; 172 } 173 if (S_ISCHR(st.st_mode)) { 174 /* 175 * If this is a character special device, then check that 176 * it's /dev/mem. If so, open kmem too. (Maybe we should 177 * make it work for either /dev/mem or /dev/kmem -- in either 178 * case you're working with a live kernel.) 179 */ 180 if (strcmp(mf, _PATH_DEVNULL) == 0) { 181 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY); 182 } else if (strcmp(mf, _PATH_MEM) != 0) { 183 _kvm_err(kd, kd->program, 184 "%s: not physical memory device", mf); 185 goto failed; 186 } else { 187 if ((kd->vmfd = open(_PATH_KMEM, flag)) < 0) { 188 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); 189 goto failed; 190 } 191 if (fcntl(kd->vmfd, F_SETFD, FD_CLOEXEC) < 0) { 192 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); 193 goto failed; 194 } 195 } 196 } else { 197 /* 198 * This is a crash dump. 199 * Initialize the virtual address translation machinery, 200 * but first setup the namelist fd. 201 */ 202 if ((kd->nlfd = open(uf, O_RDONLY, 0)) < 0) { 203 _kvm_syserr(kd, kd->program, "%s", uf); 204 goto failed; 205 } 206 if (fcntl(kd->nlfd, F_SETFD, FD_CLOEXEC) < 0) { 207 _kvm_syserr(kd, kd->program, "%s", uf); 208 goto failed; 209 } 210 if (_kvm_initvtop(kd) < 0) 211 goto failed; 212 } 213 return (kd); 214 failed: 215 /* 216 * Copy out the error if doing sane error semantics. 217 */ 218 if (errout != 0) 219 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX); 220 (void)kvm_close(kd); 221 return (0); 222 } 223 224 kvm_t * 225 kvm_openfiles(const char *uf, const char *mf, const char *sf, int flag, 226 char *errout) 227 { 228 kvm_t *kd; 229 230 if ((kd = malloc(sizeof(*kd))) == NULL) { 231 (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX); 232 return (0); 233 } 234 memset(kd, 0, sizeof(*kd)); 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, int flag, 241 const char *errstr) 242 { 243 kvm_t *kd; 244 245 if ((kd = malloc(sizeof(*kd))) == NULL) { 246 if (errstr != NULL) 247 (void)fprintf(stderr, "%s: %s\n", 248 errstr, strerror(errno)); 249 return (0); 250 } 251 memset(kd, 0, sizeof(*kd)); 252 kd->program = errstr; 253 return (_kvm_open(kd, uf, mf, flag, NULL)); 254 } 255 256 int 257 kvm_close(kvm_t *kd) 258 { 259 int error = 0; 260 261 if (kd->pmfd >= 0) 262 error |= close(kd->pmfd); 263 if (kd->vmfd >= 0) 264 error |= close(kd->vmfd); 265 if (kd->nlfd >= 0) 266 error |= close(kd->nlfd); 267 if (kd->vmst) 268 _kvm_freevtop(kd); 269 if (kd->procbase != 0) 270 free((void *)kd->procbase); 271 if (kd->argv != 0) 272 free((void *)kd->argv); 273 free((void *)kd); 274 275 return (0); 276 } 277 278 int 279 kvm_nlist(kvm_t *kd, struct nlist *nl) 280 { 281 struct nlist *p; 282 int nvalid; 283 struct kld_sym_lookup lookup; 284 285 /* 286 * If we can't use the kld symbol lookup, revert to the 287 * slow library call. 288 */ 289 if (!ISALIVE(kd)) 290 return (__fdnlist(kd->nlfd, nl)); 291 292 /* 293 * We can use the kld lookup syscall. Go through each nlist entry 294 * and look it up with a kldsym(2) syscall. 295 */ 296 nvalid = 0; 297 for (p = nl; p->n_name && p->n_name[0]; ++p) { 298 lookup.version = sizeof(lookup); 299 lookup.symname = p->n_name; 300 lookup.symvalue = 0; 301 lookup.symsize = 0; 302 303 if (lookup.symname[0] == '_') 304 lookup.symname++; 305 306 if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) { 307 p->n_type = N_TEXT; 308 p->n_other = 0; 309 p->n_desc = 0; 310 p->n_value = lookup.symvalue; 311 ++nvalid; 312 /* lookup.symsize */ 313 } 314 } 315 /* 316 * Return the number of entries that weren't found. 317 */ 318 return ((p - nl) - nvalid); 319 } 320 321 ssize_t 322 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) 323 { 324 int cc; 325 void *cp; 326 327 if (ISALIVE(kd)) { 328 /* 329 * We're using /dev/kmem. Just read straight from the 330 * device and let the active kernel do the address translation. 331 */ 332 errno = 0; 333 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 334 _kvm_err(kd, 0, "invalid address (%x)", kva); 335 return (-1); 336 } 337 338 /* 339 * Try to pre-fault the user memory to reduce instances of 340 * races within the kernel. XXX workaround for kernel bug 341 * where kernel does a sanity check, but user faults during 342 * the copy can block and race against another kernel entity 343 * unmapping the memory in question. 344 */ 345 bzero(buf, len); 346 cc = read(kd->vmfd, buf, len); 347 if (cc < 0) { 348 _kvm_syserr(kd, 0, "kvm_read"); 349 return (-1); 350 } else if (cc < len) 351 _kvm_err(kd, kd->program, "short read"); 352 return (cc); 353 } else { 354 cp = buf; 355 while (len > 0) { 356 u_long pa; 357 358 cc = _kvm_kvatop(kd, kva, &pa); 359 if (cc == 0) 360 return (-1); 361 if (cc > len) 362 cc = len; 363 errno = 0; 364 if (lseek(kd->pmfd, (off_t)pa, 0) == -1 && errno != 0) { 365 _kvm_syserr(kd, 0, _PATH_MEM); 366 break; 367 } 368 bzero(cp, cc); 369 cc = read(kd->pmfd, cp, cc); 370 if (cc < 0) { 371 _kvm_syserr(kd, kd->program, "kvm_read"); 372 break; 373 } 374 /* 375 * If kvm_kvatop returns a bogus value or our core 376 * file is truncated, we might wind up seeking beyond 377 * the end of the core file in which case the read will 378 * return 0 (EOF). 379 */ 380 if (cc == 0) 381 break; 382 cp = (char *)cp + cc; 383 kva += cc; 384 len -= cc; 385 } 386 return ((char *)cp - (char *)buf); 387 } 388 /* NOTREACHED */ 389 } 390 391 char * 392 kvm_readstr(kvm_t *kd, u_long kva, char *buf, size_t *lenp) 393 { 394 size_t len, cc, pos; 395 char ch; 396 int asize = -1; 397 398 if (buf == NULL) { 399 asize = len = 16; 400 buf = malloc(len); 401 if (buf == NULL) { 402 _kvm_syserr(kd, kd->program, "kvm_readstr"); 403 return NULL; 404 } 405 } else { 406 len = *lenp; 407 } 408 409 if (ISALIVE(kd)) { 410 /* 411 * We're using /dev/kmem. Just read straight from the 412 * device and let the active kernel do the address translation. 413 */ 414 errno = 0; 415 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 416 _kvm_err(kd, 0, "invalid address (%x)", kva); 417 return NULL; 418 } 419 420 for (pos = 0, ch = -1; ch != 0; pos++) { 421 cc = read(kd->vmfd, &ch, 1); 422 if ((ssize_t)cc < 0) { 423 _kvm_syserr(kd, 0, "kvm_readstr"); 424 return NULL; 425 } else if (cc < 1) 426 _kvm_err(kd, kd->program, "short read"); 427 if (pos == asize) { 428 buf = realloc(buf, asize *= 2); 429 if (buf == NULL) { 430 _kvm_syserr(kd, kd->program, "kvm_readstr"); 431 return NULL; 432 } 433 len = asize; 434 } 435 if (pos < len) 436 buf[pos] = ch; 437 } 438 439 if (lenp != NULL) 440 *lenp = pos; 441 if (pos > len) 442 return NULL; 443 else 444 return buf; 445 } else { 446 size_t left = 0; 447 for (pos = 0, ch = -1; ch != 0; pos++, left--, kva++) { 448 if (left == 0) { 449 u_long pa; 450 451 left = _kvm_kvatop(kd, kva, &pa); 452 if (left == 0) 453 return NULL; 454 errno = 0; 455 if (lseek(kd->pmfd, (off_t)pa, 0) == -1 && errno != 0) { 456 _kvm_syserr(kd, 0, _PATH_MEM); 457 return NULL; 458 } 459 } 460 cc = read(kd->vmfd, &ch, 1); 461 if ((ssize_t)cc < 0) { 462 _kvm_syserr(kd, 0, "kvm_readstr"); 463 return NULL; 464 } else if (cc < 1) 465 _kvm_err(kd, kd->program, "short read"); 466 if (pos == asize) { 467 buf = realloc(buf, asize *= 2); 468 if (buf == NULL) { 469 _kvm_syserr(kd, kd->program, "kvm_readstr"); 470 return NULL; 471 } 472 len = asize; 473 } 474 if (pos < len) 475 buf[pos] = ch; 476 } 477 478 if (lenp != NULL) 479 *lenp = pos; 480 if (pos > len) 481 return NULL; 482 else 483 return buf; 484 } 485 /* NOTREACHED */ 486 } 487 488 ssize_t 489 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len) 490 { 491 int cc; 492 493 if (ISALIVE(kd)) { 494 /* 495 * Just like kvm_read, only we write. 496 */ 497 errno = 0; 498 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 499 _kvm_err(kd, 0, "invalid address (%x)", kva); 500 return (-1); 501 } 502 cc = write(kd->vmfd, buf, len); 503 if (cc < 0) { 504 _kvm_syserr(kd, 0, "kvm_write"); 505 return (-1); 506 } else if (cc < len) 507 _kvm_err(kd, kd->program, "short write"); 508 return (cc); 509 } else { 510 _kvm_err(kd, kd->program, 511 "kvm_write not implemented for dead kernels"); 512 return (-1); 513 } 514 /* NOTREACHED */ 515 } 516