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 1.11 2007/12/03 14:42:45 hasso 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 (S_ISREG(st.st_mode) && st.st_size <= 0) { 171 errno = EINVAL; 172 _kvm_syserr(kd, kd->program, "empty file"); 173 goto failed; 174 } 175 if (fcntl(kd->pmfd, F_SETFD, FD_CLOEXEC) < 0) { 176 _kvm_syserr(kd, kd->program, "%s", mf); 177 goto failed; 178 } 179 if (S_ISCHR(st.st_mode)) { 180 /* 181 * If this is a character special device, then check that 182 * it's /dev/mem. If so, open kmem too. (Maybe we should 183 * make it work for either /dev/mem or /dev/kmem -- in either 184 * case you're working with a live kernel.) 185 */ 186 if (strcmp(mf, _PATH_DEVNULL) == 0) { 187 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY); 188 } else { 189 if ((kd->vmfd = open(_PATH_KMEM, flag)) < 0) { 190 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); 191 goto failed; 192 } 193 if (fcntl(kd->vmfd, F_SETFD, FD_CLOEXEC) < 0) { 194 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); 195 goto failed; 196 } 197 } 198 } else { 199 /* 200 * This is a crash dump. 201 * Initialize the virtual address translation machinery, 202 * but first setup the namelist fd. 203 */ 204 if ((kd->nlfd = open(uf, O_RDONLY, 0)) < 0) { 205 _kvm_syserr(kd, kd->program, "%s", uf); 206 goto failed; 207 } 208 if (fcntl(kd->nlfd, F_SETFD, FD_CLOEXEC) < 0) { 209 _kvm_syserr(kd, kd->program, "%s", uf); 210 goto failed; 211 } 212 if (_kvm_initvtop(kd) < 0) 213 goto failed; 214 } 215 return (kd); 216 failed: 217 /* 218 * Copy out the error if doing sane error semantics. 219 */ 220 if (errout != 0) 221 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX); 222 (void)kvm_close(kd); 223 return (0); 224 } 225 226 kvm_t * 227 kvm_openfiles(const char *uf, const char *mf, const char *sf, int flag, 228 char *errout) 229 { 230 kvm_t *kd; 231 232 if ((kd = malloc(sizeof(*kd))) == NULL) { 233 (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX); 234 return (0); 235 } 236 memset(kd, 0, sizeof(*kd)); 237 kd->program = 0; 238 return (_kvm_open(kd, uf, mf, flag, errout)); 239 } 240 241 kvm_t * 242 kvm_open(const char *uf, const char *mf, const char *sf, int flag, 243 const char *errstr) 244 { 245 kvm_t *kd; 246 247 if ((kd = malloc(sizeof(*kd))) == NULL) { 248 if (errstr != NULL) 249 (void)fprintf(stderr, "%s: %s\n", 250 errstr, strerror(errno)); 251 return (0); 252 } 253 memset(kd, 0, sizeof(*kd)); 254 kd->program = errstr; 255 return (_kvm_open(kd, uf, mf, flag, NULL)); 256 } 257 258 int 259 kvm_close(kvm_t *kd) 260 { 261 int error = 0; 262 263 if (kd->pmfd >= 0) 264 error |= close(kd->pmfd); 265 if (kd->vmfd >= 0) 266 error |= close(kd->vmfd); 267 if (kd->nlfd >= 0) 268 error |= close(kd->nlfd); 269 if (kd->vmst) 270 _kvm_freevtop(kd); 271 if (kd->procbase != NULL) 272 free(kd->procbase); 273 if (kd->argv != 0) 274 free((void *)kd->argv); 275 free((void *)kd); 276 277 return (0); 278 } 279 280 int 281 kvm_nlist(kvm_t *kd, struct nlist *nl) 282 { 283 struct nlist *p; 284 int nvalid; 285 struct kld_sym_lookup lookup; 286 287 /* 288 * If we can't use the kld symbol lookup, revert to the 289 * slow library call. 290 */ 291 if (!ISALIVE(kd)) 292 return (__fdnlist(kd->nlfd, nl)); 293 294 /* 295 * We can use the kld lookup syscall. Go through each nlist entry 296 * and look it up with a kldsym(2) syscall. 297 */ 298 nvalid = 0; 299 for (p = nl; p->n_name && p->n_name[0]; ++p) { 300 lookup.version = sizeof(lookup); 301 lookup.symname = p->n_name; 302 lookup.symvalue = 0; 303 lookup.symsize = 0; 304 305 if (lookup.symname[0] == '_') 306 lookup.symname++; 307 308 if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) { 309 p->n_type = N_TEXT; 310 p->n_other = 0; 311 p->n_desc = 0; 312 p->n_value = lookup.symvalue; 313 ++nvalid; 314 /* lookup.symsize */ 315 } 316 } 317 /* 318 * Return the number of entries that weren't found. 319 */ 320 return ((p - nl) - nvalid); 321 } 322 323 ssize_t 324 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) 325 { 326 int cc; 327 void *cp; 328 329 if (ISALIVE(kd)) { 330 /* 331 * We're using /dev/kmem. Just read straight from the 332 * device and let the active kernel do the address translation. 333 */ 334 errno = 0; 335 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 336 _kvm_err(kd, 0, "invalid address (%x)", kva); 337 return (-1); 338 } 339 340 /* 341 * Try to pre-fault the user memory to reduce instances of 342 * races within the kernel. XXX workaround for kernel bug 343 * where kernel does a sanity check, but user faults during 344 * the copy can block and race against another kernel entity 345 * unmapping the memory in question. 346 */ 347 bzero(buf, len); 348 cc = read(kd->vmfd, buf, len); 349 if (cc < 0) { 350 _kvm_syserr(kd, 0, "kvm_read"); 351 return (-1); 352 } else if (cc < len) 353 _kvm_err(kd, kd->program, "short read"); 354 return (cc); 355 } else { 356 cp = buf; 357 while (len > 0) { 358 u_long pa; 359 360 cc = _kvm_kvatop(kd, kva, &pa); 361 if (cc == 0) 362 return (-1); 363 if (cc > len) 364 cc = len; 365 errno = 0; 366 if (lseek(kd->pmfd, (off_t)pa, 0) == -1 && errno != 0) { 367 _kvm_syserr(kd, 0, _PATH_MEM); 368 break; 369 } 370 bzero(cp, cc); 371 cc = read(kd->pmfd, cp, cc); 372 if (cc < 0) { 373 _kvm_syserr(kd, kd->program, "kvm_read"); 374 break; 375 } 376 /* 377 * If kvm_kvatop returns a bogus value or our core 378 * file is truncated, we might wind up seeking beyond 379 * the end of the core file in which case the read will 380 * return 0 (EOF). 381 */ 382 if (cc == 0) 383 break; 384 cp = (char *)cp + cc; 385 kva += cc; 386 len -= cc; 387 } 388 return ((char *)cp - (char *)buf); 389 } 390 /* NOTREACHED */ 391 } 392 393 char * 394 kvm_readstr(kvm_t *kd, u_long kva, char *buf, size_t *lenp) 395 { 396 size_t len, cc, pos; 397 char ch; 398 int asize = -1; 399 400 if (buf == NULL) { 401 asize = len = 16; 402 buf = malloc(len); 403 if (buf == NULL) { 404 _kvm_syserr(kd, kd->program, "kvm_readstr"); 405 return NULL; 406 } 407 } else { 408 len = *lenp; 409 } 410 411 if (ISALIVE(kd)) { 412 /* 413 * We're using /dev/kmem. Just read straight from the 414 * device and let the active kernel do the address translation. 415 */ 416 errno = 0; 417 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 418 _kvm_err(kd, 0, "invalid address (%x)", kva); 419 return NULL; 420 } 421 422 for (pos = 0, ch = -1; ch != 0; pos++) { 423 cc = read(kd->vmfd, &ch, 1); 424 if ((ssize_t)cc < 0) { 425 _kvm_syserr(kd, 0, "kvm_readstr"); 426 return NULL; 427 } else if (cc < 1) 428 _kvm_err(kd, kd->program, "short read"); 429 if (pos == asize) { 430 buf = realloc(buf, asize *= 2); 431 if (buf == NULL) { 432 _kvm_syserr(kd, kd->program, "kvm_readstr"); 433 return NULL; 434 } 435 len = asize; 436 } 437 if (pos < len) 438 buf[pos] = ch; 439 } 440 441 if (lenp != NULL) 442 *lenp = pos; 443 if (pos > len) 444 return NULL; 445 else 446 return buf; 447 } else { 448 size_t left = 0; 449 for (pos = 0, ch = -1; ch != 0; pos++, left--, kva++) { 450 if (left == 0) { 451 u_long pa; 452 453 left = _kvm_kvatop(kd, kva, &pa); 454 if (left == 0) 455 return NULL; 456 errno = 0; 457 if (lseek(kd->pmfd, (off_t)pa, 0) == -1 && errno != 0) { 458 _kvm_syserr(kd, 0, _PATH_MEM); 459 return NULL; 460 } 461 } 462 cc = read(kd->pmfd, &ch, 1); 463 if ((ssize_t)cc < 0) { 464 _kvm_syserr(kd, 0, "kvm_readstr"); 465 return NULL; 466 } else if (cc < 1) 467 _kvm_err(kd, kd->program, "short read"); 468 if (pos == asize) { 469 buf = realloc(buf, asize *= 2); 470 if (buf == NULL) { 471 _kvm_syserr(kd, kd->program, "kvm_readstr"); 472 return NULL; 473 } 474 len = asize; 475 } 476 if (pos < len) 477 buf[pos] = ch; 478 } 479 480 if (lenp != NULL) 481 *lenp = pos; 482 if (pos > len) 483 return NULL; 484 else 485 return buf; 486 } 487 /* NOTREACHED */ 488 } 489 490 ssize_t 491 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len) 492 { 493 int cc; 494 495 if (ISALIVE(kd)) { 496 /* 497 * Just like kvm_read, only we write. 498 */ 499 errno = 0; 500 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { 501 _kvm_err(kd, 0, "invalid address (%x)", kva); 502 return (-1); 503 } 504 cc = write(kd->vmfd, buf, len); 505 if (cc < 0) { 506 _kvm_syserr(kd, 0, "kvm_write"); 507 return (-1); 508 } else if (cc < len) 509 _kvm_err(kd, kd->program, "short write"); 510 return (cc); 511 } else { 512 _kvm_err(kd, kd->program, 513 "kvm_write not implemented for dead kernels"); 514 return (-1); 515 } 516 /* NOTREACHED */ 517 } 518