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 1.10 2007/04/29 01:36:04 dillon Exp $ 40 */ 41 42 #include <sys/user.h> /* MUST BE FIRST */ 43 #include <sys/param.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 = NULL; 145 kd->procend = NULL; 146 kd->argspc = 0; 147 kd->argv = 0; 148 149 if (uf == 0) 150 uf = getbootfile(); 151 else if (strlen(uf) >= MAXPATHLEN) { 152 _kvm_err(kd, kd->program, "exec file name too long"); 153 goto failed; 154 } 155 if (flag & ~O_RDWR) { 156 _kvm_err(kd, kd->program, "bad flags arg"); 157 goto failed; 158 } 159 if (mf == 0) 160 mf = _PATH_MEM; 161 162 if ((kd->pmfd = open(mf, flag, 0)) < 0) { 163 _kvm_syserr(kd, kd->program, "%s", mf); 164 goto failed; 165 } 166 if (fstat(kd->pmfd, &st) < 0) { 167 _kvm_syserr(kd, kd->program, "%s", mf); 168 goto failed; 169 } 170 if (fcntl(kd->pmfd, F_SETFD, FD_CLOEXEC) < 0) { 171 _kvm_syserr(kd, kd->program, "%s", mf); 172 goto failed; 173 } 174 if (S_ISCHR(st.st_mode)) { 175 /* 176 * If this is a character special device, then check that 177 * it's /dev/mem. If so, open kmem too. (Maybe we should 178 * make it work for either /dev/mem or /dev/kmem -- in either 179 * case you're working with a live kernel.) 180 */ 181 if (strcmp(mf, _PATH_DEVNULL) == 0) { 182 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY); 183 } else if (strcmp(mf, _PATH_MEM) != 0) { 184 _kvm_err(kd, kd->program, 185 "%s: not physical memory device", mf); 186 goto failed; 187 } else { 188 if ((kd->vmfd = open(_PATH_KMEM, flag)) < 0) { 189 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); 190 goto failed; 191 } 192 if (fcntl(kd->vmfd, F_SETFD, FD_CLOEXEC) < 0) { 193 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); 194 goto failed; 195 } 196 } 197 } else { 198 /* 199 * This is a crash dump. 200 * Initialize the virtual address translation machinery, 201 * but first setup the namelist fd. 202 */ 203 if ((kd->nlfd = open(uf, O_RDONLY, 0)) < 0) { 204 _kvm_syserr(kd, kd->program, "%s", uf); 205 goto failed; 206 } 207 if (fcntl(kd->nlfd, F_SETFD, FD_CLOEXEC) < 0) { 208 _kvm_syserr(kd, kd->program, "%s", uf); 209 goto failed; 210 } 211 if (_kvm_initvtop(kd) < 0) 212 goto failed; 213 } 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, int flag, 227 char *errout) 228 { 229 kvm_t *kd; 230 231 if ((kd = malloc(sizeof(*kd))) == NULL) { 232 (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX); 233 return (0); 234 } 235 memset(kd, 0, sizeof(*kd)); 236 kd->program = 0; 237 return (_kvm_open(kd, uf, mf, flag, errout)); 238 } 239 240 kvm_t * 241 kvm_open(const char *uf, const char *mf, const char *sf, int flag, 242 const char *errstr) 243 { 244 kvm_t *kd; 245 246 if ((kd = malloc(sizeof(*kd))) == NULL) { 247 if (errstr != NULL) 248 (void)fprintf(stderr, "%s: %s\n", 249 errstr, strerror(errno)); 250 return (0); 251 } 252 memset(kd, 0, sizeof(*kd)); 253 kd->program = errstr; 254 return (_kvm_open(kd, uf, mf, flag, NULL)); 255 } 256 257 int 258 kvm_close(kvm_t *kd) 259 { 260 int error = 0; 261 262 if (kd->pmfd >= 0) 263 error |= close(kd->pmfd); 264 if (kd->vmfd >= 0) 265 error |= close(kd->vmfd); 266 if (kd->nlfd >= 0) 267 error |= close(kd->nlfd); 268 if (kd->vmst) 269 _kvm_freevtop(kd); 270 if (kd->procbase != NULL) 271 free(kd->procbase); 272 if (kd->argv != 0) 273 free((void *)kd->argv); 274 free((void *)kd); 275 276 return (0); 277 } 278 279 int 280 kvm_nlist(kvm_t *kd, struct nlist *nl) 281 { 282 struct nlist *p; 283 int nvalid; 284 struct kld_sym_lookup lookup; 285 286 /* 287 * If we can't use the kld symbol lookup, revert to the 288 * slow library call. 289 */ 290 if (!ISALIVE(kd)) 291 return (__fdnlist(kd->nlfd, nl)); 292 293 /* 294 * We can use the kld lookup syscall. Go through each nlist entry 295 * and look it up with a kldsym(2) syscall. 296 */ 297 nvalid = 0; 298 for (p = nl; p->n_name && p->n_name[0]; ++p) { 299 lookup.version = sizeof(lookup); 300 lookup.symname = p->n_name; 301 lookup.symvalue = 0; 302 lookup.symsize = 0; 303 304 if (lookup.symname[0] == '_') 305 lookup.symname++; 306 307 if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) { 308 p->n_type = N_TEXT; 309 p->n_other = 0; 310 p->n_desc = 0; 311 p->n_value = lookup.symvalue; 312 ++nvalid; 313 /* lookup.symsize */ 314 } 315 } 316 /* 317 * Return the number of entries that weren't found. 318 */ 319 return ((p - nl) - nvalid); 320 } 321 322 ssize_t 323 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) 324 { 325 int cc; 326 void *cp; 327 328 if (ISALIVE(kd)) { 329 /* 330 * We're using /dev/kmem. Just read straight from the 331 * device and let the active kernel do the address translation. 332 */ 333 errno = 0; 334 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 335 _kvm_err(kd, 0, "invalid address (%x)", kva); 336 return (-1); 337 } 338 339 /* 340 * Try to pre-fault the user memory to reduce instances of 341 * races within the kernel. XXX workaround for kernel bug 342 * where kernel does a sanity check, but user faults during 343 * the copy can block and race against another kernel entity 344 * unmapping the memory in question. 345 */ 346 bzero(buf, len); 347 cc = read(kd->vmfd, buf, len); 348 if (cc < 0) { 349 _kvm_syserr(kd, 0, "kvm_read"); 350 return (-1); 351 } else if (cc < len) 352 _kvm_err(kd, kd->program, "short read"); 353 return (cc); 354 } else { 355 cp = buf; 356 while (len > 0) { 357 u_long pa; 358 359 cc = _kvm_kvatop(kd, kva, &pa); 360 if (cc == 0) 361 return (-1); 362 if (cc > len) 363 cc = len; 364 errno = 0; 365 if (lseek(kd->pmfd, (off_t)pa, 0) == -1 && errno != 0) { 366 _kvm_syserr(kd, 0, _PATH_MEM); 367 break; 368 } 369 bzero(cp, cc); 370 cc = read(kd->pmfd, cp, cc); 371 if (cc < 0) { 372 _kvm_syserr(kd, kd->program, "kvm_read"); 373 break; 374 } 375 /* 376 * If kvm_kvatop returns a bogus value or our core 377 * file is truncated, we might wind up seeking beyond 378 * the end of the core file in which case the read will 379 * return 0 (EOF). 380 */ 381 if (cc == 0) 382 break; 383 cp = (char *)cp + cc; 384 kva += cc; 385 len -= cc; 386 } 387 return ((char *)cp - (char *)buf); 388 } 389 /* NOTREACHED */ 390 } 391 392 char * 393 kvm_readstr(kvm_t *kd, u_long kva, char *buf, size_t *lenp) 394 { 395 size_t len, cc, pos; 396 char ch; 397 int asize = -1; 398 399 if (buf == NULL) { 400 asize = len = 16; 401 buf = malloc(len); 402 if (buf == NULL) { 403 _kvm_syserr(kd, kd->program, "kvm_readstr"); 404 return NULL; 405 } 406 } else { 407 len = *lenp; 408 } 409 410 if (ISALIVE(kd)) { 411 /* 412 * We're using /dev/kmem. Just read straight from the 413 * device and let the active kernel do the address translation. 414 */ 415 errno = 0; 416 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 417 _kvm_err(kd, 0, "invalid address (%x)", kva); 418 return NULL; 419 } 420 421 for (pos = 0, ch = -1; ch != 0; pos++) { 422 cc = read(kd->vmfd, &ch, 1); 423 if ((ssize_t)cc < 0) { 424 _kvm_syserr(kd, 0, "kvm_readstr"); 425 return NULL; 426 } else if (cc < 1) 427 _kvm_err(kd, kd->program, "short read"); 428 if (pos == asize) { 429 buf = realloc(buf, asize *= 2); 430 if (buf == NULL) { 431 _kvm_syserr(kd, kd->program, "kvm_readstr"); 432 return NULL; 433 } 434 len = asize; 435 } 436 if (pos < len) 437 buf[pos] = ch; 438 } 439 440 if (lenp != NULL) 441 *lenp = pos; 442 if (pos > len) 443 return NULL; 444 else 445 return buf; 446 } else { 447 size_t left = 0; 448 for (pos = 0, ch = -1; ch != 0; pos++, left--, kva++) { 449 if (left == 0) { 450 u_long pa; 451 452 left = _kvm_kvatop(kd, kva, &pa); 453 if (left == 0) 454 return NULL; 455 errno = 0; 456 if (lseek(kd->pmfd, (off_t)pa, 0) == -1 && errno != 0) { 457 _kvm_syserr(kd, 0, _PATH_MEM); 458 return NULL; 459 } 460 } 461 cc = read(kd->vmfd, &ch, 1); 462 if ((ssize_t)cc < 0) { 463 _kvm_syserr(kd, 0, "kvm_readstr"); 464 return NULL; 465 } else if (cc < 1) 466 _kvm_err(kd, kd->program, "short read"); 467 if (pos == asize) { 468 buf = realloc(buf, asize *= 2); 469 if (buf == NULL) { 470 _kvm_syserr(kd, kd->program, "kvm_readstr"); 471 return NULL; 472 } 473 len = asize; 474 } 475 if (pos < len) 476 buf[pos] = ch; 477 } 478 479 if (lenp != NULL) 480 *lenp = pos; 481 if (pos > len) 482 return NULL; 483 else 484 return buf; 485 } 486 /* NOTREACHED */ 487 } 488 489 ssize_t 490 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len) 491 { 492 int cc; 493 494 if (ISALIVE(kd)) { 495 /* 496 * Just like kvm_read, only we write. 497 */ 498 errno = 0; 499 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 500 _kvm_err(kd, 0, "invalid address (%x)", kva); 501 return (-1); 502 } 503 cc = write(kd->vmfd, buf, len); 504 if (cc < 0) { 505 _kvm_syserr(kd, 0, "kvm_write"); 506 return (-1); 507 } else if (cc < len) 508 _kvm_err(kd, kd->program, "short write"); 509 return (cc); 510 } else { 511 _kvm_err(kd, kd->program, 512 "kvm_write not implemented for dead kernels"); 513 return (-1); 514 } 515 /* NOTREACHED */ 516 } 517