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