1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1992, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software developed by the Computer Systems
8 * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
9 * BG 91-66 and contributed to Berkeley.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36
37 #include <sys/param.h>
38 #include <sys/fnv_hash.h>
39
40 #define _WANT_VNET
41
42 #include <sys/user.h>
43 #include <sys/linker.h>
44 #include <sys/pcpu.h>
45 #include <sys/stat.h>
46 #include <sys/sysctl.h>
47 #include <sys/mman.h>
48
49 #include <stdbool.h>
50 #include <net/vnet.h>
51
52 #include <fcntl.h>
53 #include <kvm.h>
54 #include <limits.h>
55 #include <paths.h>
56 #include <stdint.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <unistd.h>
61
62 #include "kvm_private.h"
63
64 SET_DECLARE(kvm_arch, struct kvm_arch);
65
66 static char _kd_is_null[] = "";
67
68 char *
kvm_geterr(kvm_t * kd)69 kvm_geterr(kvm_t *kd)
70 {
71
72 if (kd == NULL)
73 return (_kd_is_null);
74 return (kd->errbuf);
75 }
76
77 static int
_kvm_read_kernel_ehdr(kvm_t * kd)78 _kvm_read_kernel_ehdr(kvm_t *kd)
79 {
80 Elf *elf;
81
82 if (elf_version(EV_CURRENT) == EV_NONE) {
83 _kvm_err(kd, kd->program, "Unsupported libelf");
84 return (-1);
85 }
86 elf = elf_begin(kd->nlfd, ELF_C_READ, NULL);
87 if (elf == NULL) {
88 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
89 return (-1);
90 }
91 if (elf_kind(elf) != ELF_K_ELF) {
92 _kvm_err(kd, kd->program, "kernel is not an ELF file");
93 return (-1);
94 }
95 if (gelf_getehdr(elf, &kd->nlehdr) == NULL) {
96 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
97 elf_end(elf);
98 return (-1);
99 }
100 elf_end(elf);
101
102 switch (kd->nlehdr.e_ident[EI_DATA]) {
103 case ELFDATA2LSB:
104 case ELFDATA2MSB:
105 return (0);
106 default:
107 _kvm_err(kd, kd->program,
108 "unsupported ELF data encoding for kernel");
109 return (-1);
110 }
111 }
112
113 static kvm_t *
_kvm_open(kvm_t * kd,const char * uf,const char * mf,int flag,char * errout)114 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
115 {
116 struct kvm_arch **parch;
117 struct stat st;
118
119 kd->vmfd = -1;
120 kd->pmfd = -1;
121 kd->nlfd = -1;
122 kd->vmst = NULL;
123 kd->procbase = NULL;
124 kd->argspc = NULL;
125 kd->argv = NULL;
126
127 if (uf == NULL)
128 uf = getbootfile();
129 else if (strlen(uf) >= MAXPATHLEN) {
130 _kvm_err(kd, kd->program, "exec file name too long");
131 goto failed;
132 }
133 if (flag & ~O_RDWR) {
134 _kvm_err(kd, kd->program, "bad flags arg");
135 goto failed;
136 }
137 if (mf == NULL)
138 mf = _PATH_MEM;
139
140 if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) {
141 _kvm_syserr(kd, kd->program, "%s", mf);
142 goto failed;
143 }
144 if (fstat(kd->pmfd, &st) < 0) {
145 _kvm_syserr(kd, kd->program, "%s", mf);
146 goto failed;
147 }
148 if (S_ISREG(st.st_mode) && st.st_size <= 0) {
149 errno = EINVAL;
150 _kvm_syserr(kd, kd->program, "empty file");
151 goto failed;
152 }
153 if (S_ISCHR(st.st_mode)) {
154 /*
155 * If this is a character special device, then check that
156 * it's /dev/mem. If so, open kmem too. (Maybe we should
157 * make it work for either /dev/mem or /dev/kmem -- in either
158 * case you're working with a live kernel.)
159 */
160 if (strcmp(mf, _PATH_DEVNULL) == 0) {
161 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY | O_CLOEXEC);
162 return (kd);
163 } else if (strcmp(mf, _PATH_MEM) == 0) {
164 if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) <
165 0) {
166 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
167 goto failed;
168 }
169 return (kd);
170 }
171 }
172
173 /*
174 * This is either a crash dump or a remote live system with its physical
175 * memory fully accessible via a special device.
176 * Open the namelist fd and determine the architecture.
177 */
178 if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) {
179 _kvm_syserr(kd, kd->program, "%s", uf);
180 goto failed;
181 }
182 if (_kvm_read_kernel_ehdr(kd) < 0)
183 goto failed;
184 if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0 ||
185 strncmp(mf, _PATH_DEVVMM, strlen(_PATH_DEVVMM)) == 0) {
186 kd->rawdump = 1;
187 kd->writable = 1;
188 }
189 SET_FOREACH(parch, kvm_arch) {
190 if ((*parch)->ka_probe(kd)) {
191 kd->arch = *parch;
192 break;
193 }
194 }
195 if (kd->arch == NULL) {
196 _kvm_err(kd, kd->program, "unsupported architecture");
197 goto failed;
198 }
199
200 /*
201 * Non-native kernels require a symbol resolver.
202 */
203 if (!kd->arch->ka_native(kd) && kd->resolve_symbol == NULL) {
204 _kvm_err(kd, kd->program,
205 "non-native kernel requires a symbol resolver");
206 goto failed;
207 }
208
209 /*
210 * Initialize the virtual address translation machinery.
211 */
212 if (kd->arch->ka_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 != NULL)
220 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX);
221 (void)kvm_close(kd);
222 return (NULL);
223 }
224
225 kvm_t *
kvm_openfiles(const char * uf,const char * mf,const char * sf __unused,int flag,char * errout)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 if (errout != NULL)
233 (void)strlcpy(errout, strerror(errno),
234 _POSIX2_LINE_MAX);
235 return (NULL);
236 }
237 return (_kvm_open(kd, uf, mf, flag, errout));
238 }
239
240 kvm_t *
kvm_open(const char * uf,const char * mf,const char * sf __unused,int flag,const char * errstr)241 kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag,
242 const char *errstr)
243 {
244 kvm_t *kd;
245
246 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
247 if (errstr != NULL)
248 (void)fprintf(stderr, "%s: %s\n",
249 errstr, strerror(errno));
250 return (NULL);
251 }
252 kd->program = errstr;
253 return (_kvm_open(kd, uf, mf, flag, NULL));
254 }
255
256 kvm_t *
kvm_open2(const char * uf,const char * mf,int flag,char * errout,int (* resolver)(const char *,kvaddr_t *))257 kvm_open2(const char *uf, const char *mf, int flag, char *errout,
258 int (*resolver)(const char *, kvaddr_t *))
259 {
260 kvm_t *kd;
261
262 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
263 if (errout != NULL)
264 (void)strlcpy(errout, strerror(errno),
265 _POSIX2_LINE_MAX);
266 return (NULL);
267 }
268 kd->resolve_symbol = resolver;
269 return (_kvm_open(kd, uf, mf, flag, errout));
270 }
271
272 int
kvm_close(kvm_t * kd)273 kvm_close(kvm_t *kd)
274 {
275 int error = 0;
276
277 if (kd == NULL) {
278 errno = EINVAL;
279 return (-1);
280 }
281 if (kd->vmst != NULL)
282 kd->arch->ka_freevtop(kd);
283 if (kd->pmfd >= 0)
284 error |= close(kd->pmfd);
285 if (kd->vmfd >= 0)
286 error |= close(kd->vmfd);
287 if (kd->nlfd >= 0)
288 error |= close(kd->nlfd);
289 if (kd->procbase != 0)
290 free((void *)kd->procbase);
291 if (kd->argbuf != 0)
292 free((void *) kd->argbuf);
293 if (kd->argspc != 0)
294 free((void *) kd->argspc);
295 if (kd->argv != 0)
296 free((void *)kd->argv);
297 if (kd->dpcpu_initialized != 0)
298 free(kd->dpcpu_off);
299 if (kd->pt_map != NULL)
300 free(kd->pt_map);
301 if (kd->page_map != NULL)
302 free(kd->page_map);
303 if (kd->sparse_map != MAP_FAILED && kd->sparse_map != NULL)
304 munmap(kd->sparse_map, kd->pt_sparse_size);
305 free((void *)kd);
306
307 return (error);
308 }
309
310 int
kvm_nlist2(kvm_t * kd,struct kvm_nlist * nl)311 kvm_nlist2(kvm_t *kd, struct kvm_nlist *nl)
312 {
313
314 /*
315 * If called via the public interface, permit initialization of
316 * further virtualized modules on demand.
317 */
318 return (_kvm_nlist(kd, nl, 1));
319 }
320
321 int
kvm_nlist(kvm_t * kd,struct nlist * nl)322 kvm_nlist(kvm_t *kd, struct nlist *nl)
323 {
324 struct kvm_nlist *kl;
325 int count, i, nfail;
326
327 /*
328 * Avoid reporting truncated addresses by failing for non-native
329 * cores.
330 */
331 if (!kvm_native(kd)) {
332 _kvm_err(kd, kd->program, "kvm_nlist of non-native vmcore");
333 return (-1);
334 }
335
336 for (count = 0; nl[count].n_name != NULL && nl[count].n_name[0] != '\0';
337 count++)
338 ;
339 if (count == 0)
340 return (0);
341 kl = calloc(count + 1, sizeof(*kl));
342 if (kl == NULL) {
343 _kvm_err(kd, kd->program, "cannot allocate memory");
344 return (-1);
345 }
346 for (i = 0; i < count; i++)
347 kl[i].n_name = nl[i].n_name;
348 nfail = kvm_nlist2(kd, kl);
349 for (i = 0; i < count; i++) {
350 nl[i].n_type = kl[i].n_type;
351 nl[i].n_other = 0;
352 nl[i].n_desc = 0;
353 nl[i].n_value = kl[i].n_value;
354 }
355 free(kl);
356 return (nfail);
357 }
358
359 ssize_t
kvm_read(kvm_t * kd,u_long kva,void * buf,size_t len)360 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len)
361 {
362
363 return (kvm_read2(kd, kva, buf, len));
364 }
365
366 ssize_t
kvm_read2(kvm_t * kd,kvaddr_t kva,void * buf,size_t len)367 kvm_read2(kvm_t *kd, kvaddr_t kva, void *buf, size_t len)
368 {
369 int cc;
370 ssize_t cr;
371 off_t pa;
372 char *cp;
373
374 if (ISALIVE(kd)) {
375 /*
376 * We're using /dev/kmem. Just read straight from the
377 * device and let the active kernel do the address translation.
378 */
379 errno = 0;
380 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
381 _kvm_err(kd, 0, "invalid address (0x%jx)",
382 (uintmax_t)kva);
383 return (-1);
384 }
385 cr = read(kd->vmfd, buf, len);
386 if (cr < 0) {
387 _kvm_syserr(kd, 0, "kvm_read");
388 return (-1);
389 } else if (cr < (ssize_t)len)
390 _kvm_err(kd, kd->program, "short read");
391 return (cr);
392 }
393
394 cp = buf;
395 while (len > 0) {
396 cc = kd->arch->ka_kvatop(kd, kva, &pa);
397 if (cc == 0)
398 return (-1);
399 if (cc > (ssize_t)len)
400 cc = len;
401 errno = 0;
402 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
403 _kvm_syserr(kd, 0, _PATH_MEM);
404 break;
405 }
406 cr = read(kd->pmfd, cp, cc);
407 if (cr < 0) {
408 _kvm_syserr(kd, kd->program, "kvm_read");
409 break;
410 }
411 /*
412 * If ka_kvatop returns a bogus value or our core file is
413 * truncated, we might wind up seeking beyond the end of the
414 * core file in which case the read will return 0 (EOF).
415 */
416 if (cr == 0)
417 break;
418 cp += cr;
419 kva += cr;
420 len -= cr;
421 }
422
423 return (cp - (char *)buf);
424 }
425
426 ssize_t
kvm_write(kvm_t * kd,u_long kva,const void * buf,size_t len)427 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len)
428 {
429 int cc;
430 ssize_t cw;
431 off_t pa;
432 const char *cp;
433
434 if (!ISALIVE(kd) && !kd->writable) {
435 _kvm_err(kd, kd->program,
436 "kvm_write not implemented for dead kernels");
437 return (-1);
438 }
439
440 if (ISALIVE(kd)) {
441 /*
442 * Just like kvm_read, only we write.
443 */
444 errno = 0;
445 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
446 _kvm_err(kd, 0, "invalid address (%lx)", kva);
447 return (-1);
448 }
449 cc = write(kd->vmfd, buf, len);
450 if (cc < 0) {
451 _kvm_syserr(kd, 0, "kvm_write");
452 return (-1);
453 } else if ((size_t)cc < len)
454 _kvm_err(kd, kd->program, "short write");
455 return (cc);
456 }
457
458 cp = buf;
459 while (len > 0) {
460 cc = kd->arch->ka_kvatop(kd, kva, &pa);
461 if (cc == 0)
462 return (-1);
463 if (cc > (ssize_t)len)
464 cc = len;
465 errno = 0;
466 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
467 _kvm_syserr(kd, 0, _PATH_MEM);
468 break;
469 }
470 cw = write(kd->pmfd, cp, cc);
471 if (cw < 0) {
472 _kvm_syserr(kd, kd->program, "kvm_write");
473 break;
474 }
475 /*
476 * If ka_kvatop returns a bogus value or our core file is
477 * truncated, we might wind up seeking beyond the end of the
478 * core file in which case the read will return 0 (EOF).
479 */
480 if (cw == 0)
481 break;
482 cp += cw;
483 kva += cw;
484 len -= cw;
485 }
486
487 return (cp - (const char *)buf);
488 }
489
490 int
kvm_native(kvm_t * kd)491 kvm_native(kvm_t *kd)
492 {
493
494 if (ISALIVE(kd))
495 return (1);
496 return (kd->arch->ka_native(kd));
497 }
498
499 int
kvm_walk_pages(kvm_t * kd,kvm_walk_pages_cb_t * cb,void * closure)500 kvm_walk_pages(kvm_t *kd, kvm_walk_pages_cb_t *cb, void *closure)
501 {
502
503 if (kd->arch->ka_walk_pages == NULL)
504 return (0);
505
506 return (kd->arch->ka_walk_pages(kd, cb, closure));
507 }
508
509 kssize_t
kvm_kerndisp(kvm_t * kd)510 kvm_kerndisp(kvm_t *kd)
511 {
512 unsigned long kernbase, rel_kernbase;
513 size_t kernbase_len = sizeof(kernbase);
514 size_t rel_kernbase_len = sizeof(rel_kernbase);
515
516 if (ISALIVE(kd)) {
517 if (sysctlbyname("kern.base_address", &kernbase,
518 &kernbase_len, NULL, 0) == -1) {
519 _kvm_syserr(kd, kd->program,
520 "failed to get kernel base address");
521 return (0);
522 }
523 if (sysctlbyname("kern.relbase_address", &rel_kernbase,
524 &rel_kernbase_len, NULL, 0) == -1) {
525 _kvm_syserr(kd, kd->program,
526 "failed to get relocated kernel base address");
527 return (0);
528 }
529 return (rel_kernbase - kernbase);
530 }
531
532 if (kd->arch->ka_kerndisp == NULL)
533 return (0);
534
535 return (kd->arch->ka_kerndisp(kd));
536 }
537