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 #include <sys/fnv_hash.h>
45
46 #define _WANT_VNET
47
48 #include <sys/user.h>
49 #include <sys/linker.h>
50 #include <sys/pcpu.h>
51 #include <sys/stat.h>
52
53 #include <net/vnet.h>
54
55 #include <fcntl.h>
56 #include <kvm.h>
57 #include <limits.h>
58 #include <paths.h>
59 #include <stdint.h>
60 #include <stdio.h>
61 #include <stdlib.h>
62 #include <string.h>
63 #include <unistd.h>
64
65 #include "kvm_private.h"
66
67 SET_DECLARE(kvm_arch, struct kvm_arch);
68
69 /* from src/lib/libc/gen/nlist.c */
70 int __fdnlist(int, struct nlist *);
71
72 static int
kvm_fdnlist(kvm_t * kd,struct kvm_nlist * list)73 kvm_fdnlist(kvm_t *kd, struct kvm_nlist *list)
74 {
75 kvaddr_t addr;
76 int error, nfail;
77
78 if (kd->resolve_symbol == NULL) {
79 struct nlist *nl;
80 int count, i;
81
82 for (count = 0; list[count].n_name != NULL &&
83 list[count].n_name[0] != '\0'; count++)
84 ;
85 nl = calloc(count + 1, sizeof(*nl));
86 for (i = 0; i < count; i++)
87 nl[i].n_name = list[i].n_name;
88 nfail = __fdnlist(kd->nlfd, nl);
89 for (i = 0; i < count; i++) {
90 list[i].n_type = nl[i].n_type;
91 list[i].n_value = nl[i].n_value;
92 }
93 free(nl);
94 return (nfail);
95 }
96
97 nfail = 0;
98 while (list->n_name != NULL && list->n_name[0] != '\0') {
99 error = kd->resolve_symbol(list->n_name, &addr);
100 if (error != 0) {
101 nfail++;
102 list->n_value = 0;
103 list->n_type = 0;
104 } else {
105 list->n_value = addr;
106 list->n_type = N_DATA | N_EXT;
107 }
108 list++;
109 }
110 return (nfail);
111 }
112
113 char *
kvm_geterr(kvm_t * kd)114 kvm_geterr(kvm_t *kd)
115 {
116 return (kd->errbuf);
117 }
118
119 #include <stdarg.h>
120
121 /*
122 * Report an error using printf style arguments. "program" is kd->program
123 * on hard errors, and 0 on soft errors, so that under sun error emulation,
124 * only hard errors are printed out (otherwise, programs like gdb will
125 * generate tons of error messages when trying to access bogus pointers).
126 */
127 void
_kvm_err(kvm_t * kd,const char * program,const char * fmt,...)128 _kvm_err(kvm_t *kd, const char *program, const char *fmt, ...)
129 {
130 va_list ap;
131
132 va_start(ap, fmt);
133 if (program != NULL) {
134 (void)fprintf(stderr, "%s: ", program);
135 (void)vfprintf(stderr, fmt, ap);
136 (void)fputc('\n', stderr);
137 } else
138 (void)vsnprintf(kd->errbuf,
139 sizeof(kd->errbuf), fmt, ap);
140
141 va_end(ap);
142 }
143
144 void
_kvm_syserr(kvm_t * kd,const char * program,const char * fmt,...)145 _kvm_syserr(kvm_t *kd, const char *program, const char *fmt, ...)
146 {
147 va_list ap;
148 int n;
149
150 va_start(ap, fmt);
151 if (program != NULL) {
152 (void)fprintf(stderr, "%s: ", program);
153 (void)vfprintf(stderr, fmt, ap);
154 (void)fprintf(stderr, ": %s\n", strerror(errno));
155 } else {
156 char *cp = kd->errbuf;
157
158 (void)vsnprintf(cp, sizeof(kd->errbuf), fmt, ap);
159 n = strlen(cp);
160 (void)snprintf(&cp[n], sizeof(kd->errbuf) - n, ": %s",
161 strerror(errno));
162 }
163 va_end(ap);
164 }
165
166 void *
_kvm_malloc(kvm_t * kd,size_t n)167 _kvm_malloc(kvm_t *kd, size_t n)
168 {
169 void *p;
170
171 if ((p = calloc(n, sizeof(char))) == NULL)
172 _kvm_err(kd, kd->program, "can't allocate %zu bytes: %s",
173 n, strerror(errno));
174 return (p);
175 }
176
177 static int
_kvm_read_kernel_ehdr(kvm_t * kd)178 _kvm_read_kernel_ehdr(kvm_t *kd)
179 {
180 Elf *elf;
181
182 if (elf_version(EV_CURRENT) == EV_NONE) {
183 _kvm_err(kd, kd->program, "Unsupported libelf");
184 return (-1);
185 }
186 elf = elf_begin(kd->nlfd, ELF_C_READ, NULL);
187 if (elf == NULL) {
188 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
189 return (-1);
190 }
191 if (elf_kind(elf) != ELF_K_ELF) {
192 _kvm_err(kd, kd->program, "kernel is not an ELF file");
193 return (-1);
194 }
195 if (gelf_getehdr(elf, &kd->nlehdr) == NULL) {
196 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
197 elf_end(elf);
198 return (-1);
199 }
200 elf_end(elf);
201
202 switch (kd->nlehdr.e_ident[EI_DATA]) {
203 case ELFDATA2LSB:
204 case ELFDATA2MSB:
205 return (0);
206 default:
207 _kvm_err(kd, kd->program,
208 "unsupported ELF data encoding for kernel");
209 return (-1);
210 }
211 }
212
213 int
_kvm_probe_elf_kernel(kvm_t * kd,int class,int machine)214 _kvm_probe_elf_kernel(kvm_t *kd, int class, int machine)
215 {
216
217 return (kd->nlehdr.e_ident[EI_CLASS] == class &&
218 kd->nlehdr.e_type == ET_EXEC &&
219 kd->nlehdr.e_machine == machine);
220 }
221
222 int
_kvm_is_minidump(kvm_t * kd)223 _kvm_is_minidump(kvm_t *kd)
224 {
225 char minihdr[8];
226
227 if (kd->rawdump)
228 return (0);
229 if (pread(kd->pmfd, &minihdr, 8, 0) == 8 &&
230 memcmp(&minihdr, "minidump", 8) == 0)
231 return (1);
232 return (0);
233 }
234
235 /*
236 * The powerpc backend has a hack to strip a leading kerneldump
237 * header from the core before treating it as an ELF header.
238 *
239 * We can add that here if we can get a change to libelf to support
240 * an inital offset into the file. Alternatively we could patch
241 * savecore to extract cores from a regular file instead.
242 */
243 int
_kvm_read_core_phdrs(kvm_t * kd,size_t * phnump,GElf_Phdr ** phdrp)244 _kvm_read_core_phdrs(kvm_t *kd, size_t *phnump, GElf_Phdr **phdrp)
245 {
246 GElf_Ehdr ehdr;
247 GElf_Phdr *phdr;
248 Elf *elf;
249 size_t i, phnum;
250
251 elf = elf_begin(kd->pmfd, ELF_C_READ, NULL);
252 if (elf == NULL) {
253 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
254 return (-1);
255 }
256 if (elf_kind(elf) != ELF_K_ELF) {
257 _kvm_err(kd, kd->program, "invalid core");
258 goto bad;
259 }
260 if (gelf_getclass(elf) != kd->nlehdr.e_ident[EI_CLASS]) {
261 _kvm_err(kd, kd->program, "invalid core");
262 goto bad;
263 }
264 if (gelf_getehdr(elf, &ehdr) == NULL) {
265 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
266 goto bad;
267 }
268 if (ehdr.e_type != ET_CORE) {
269 _kvm_err(kd, kd->program, "invalid core");
270 goto bad;
271 }
272 if (ehdr.e_machine != kd->nlehdr.e_machine) {
273 _kvm_err(kd, kd->program, "invalid core");
274 goto bad;
275 }
276
277 if (elf_getphdrnum(elf, &phnum) == -1) {
278 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
279 goto bad;
280 }
281
282 phdr = calloc(phnum, sizeof(*phdr));
283 if (phdr == NULL) {
284 _kvm_err(kd, kd->program, "failed to allocate phdrs");
285 goto bad;
286 }
287
288 for (i = 0; i < phnum; i++) {
289 if (gelf_getphdr(elf, i, &phdr[i]) == NULL) {
290 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
291 goto bad;
292 }
293 }
294 elf_end(elf);
295 *phnump = phnum;
296 *phdrp = phdr;
297 return (0);
298
299 bad:
300 elf_end(elf);
301 return (-1);
302 }
303
304 static void
_kvm_hpt_insert(struct hpt * hpt,uint64_t pa,off_t off)305 _kvm_hpt_insert(struct hpt *hpt, uint64_t pa, off_t off)
306 {
307 struct hpte *hpte;
308 uint32_t fnv = FNV1_32_INIT;
309
310 fnv = fnv_32_buf(&pa, sizeof(pa), fnv);
311 fnv &= (HPT_SIZE - 1);
312 hpte = malloc(sizeof(*hpte));
313 hpte->pa = pa;
314 hpte->off = off;
315 hpte->next = hpt->hpt_head[fnv];
316 hpt->hpt_head[fnv] = hpte;
317 }
318
319 void
_kvm_hpt_init(kvm_t * kd,struct hpt * hpt,void * base,size_t len,off_t off,int page_size,int word_size)320 _kvm_hpt_init(kvm_t *kd, struct hpt *hpt, void *base, size_t len, off_t off,
321 int page_size, int word_size)
322 {
323 uint64_t bits, idx, pa;
324 uint64_t *base64;
325 uint32_t *base32;
326
327 base64 = base;
328 base32 = base;
329 for (idx = 0; idx < len / word_size; idx++) {
330 if (word_size == sizeof(uint64_t))
331 bits = _kvm64toh(kd, base64[idx]);
332 else
333 bits = _kvm32toh(kd, base32[idx]);
334 pa = idx * word_size * NBBY * page_size;
335 for (; bits != 0; bits >>= 1, pa += page_size) {
336 if ((bits & 1) == 0)
337 continue;
338 _kvm_hpt_insert(hpt, pa, off);
339 off += page_size;
340 }
341 }
342 }
343
344 off_t
_kvm_hpt_find(struct hpt * hpt,uint64_t pa)345 _kvm_hpt_find(struct hpt *hpt, uint64_t pa)
346 {
347 struct hpte *hpte;
348 uint32_t fnv = FNV1_32_INIT;
349
350 fnv = fnv_32_buf(&pa, sizeof(pa), fnv);
351 fnv &= (HPT_SIZE - 1);
352 for (hpte = hpt->hpt_head[fnv]; hpte != NULL; hpte = hpte->next) {
353 if (pa == hpte->pa)
354 return (hpte->off);
355 }
356 return (-1);
357 }
358
359 void
_kvm_hpt_free(struct hpt * hpt)360 _kvm_hpt_free(struct hpt *hpt)
361 {
362 struct hpte *hpte, *next;
363 int i;
364
365 for (i = 0; i < HPT_SIZE; i++) {
366 for (hpte = hpt->hpt_head[i]; hpte != NULL; hpte = next) {
367 next = hpte->next;
368 free(hpte);
369 }
370 }
371 }
372
373 static kvm_t *
_kvm_open(kvm_t * kd,const char * uf,const char * mf,int flag,char * errout)374 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
375 {
376 struct kvm_arch **parch;
377 struct stat st;
378
379 kd->vmfd = -1;
380 kd->pmfd = -1;
381 kd->nlfd = -1;
382 kd->vmst = 0;
383 kd->procbase = 0;
384 kd->argspc = 0;
385 kd->argv = 0;
386
387 if (uf == 0)
388 uf = getbootfile();
389 else if (strlen(uf) >= MAXPATHLEN) {
390 _kvm_err(kd, kd->program, "exec file name too long");
391 goto failed;
392 }
393 if (flag & ~O_RDWR) {
394 _kvm_err(kd, kd->program, "bad flags arg");
395 goto failed;
396 }
397 if (mf == 0)
398 mf = _PATH_MEM;
399
400 if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) {
401 _kvm_syserr(kd, kd->program, "%s", mf);
402 goto failed;
403 }
404 if (fstat(kd->pmfd, &st) < 0) {
405 _kvm_syserr(kd, kd->program, "%s", mf);
406 goto failed;
407 }
408 if (S_ISREG(st.st_mode) && st.st_size <= 0) {
409 errno = EINVAL;
410 _kvm_syserr(kd, kd->program, "empty file");
411 goto failed;
412 }
413 if (S_ISCHR(st.st_mode)) {
414 /*
415 * If this is a character special device, then check that
416 * it's /dev/mem. If so, open kmem too. (Maybe we should
417 * make it work for either /dev/mem or /dev/kmem -- in either
418 * case you're working with a live kernel.)
419 */
420 if (strcmp(mf, _PATH_DEVNULL) == 0) {
421 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY | O_CLOEXEC);
422 return (kd);
423 } else if (strcmp(mf, _PATH_MEM) == 0) {
424 if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) <
425 0) {
426 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
427 goto failed;
428 }
429 return (kd);
430 }
431 }
432 /*
433 * This is a crash dump.
434 * Open the namelist fd and determine the architecture.
435 */
436 if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) {
437 _kvm_syserr(kd, kd->program, "%s", uf);
438 goto failed;
439 }
440 if (_kvm_read_kernel_ehdr(kd) < 0)
441 goto failed;
442 if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0)
443 kd->rawdump = 1;
444 SET_FOREACH(parch, kvm_arch) {
445 if ((*parch)->ka_probe(kd)) {
446 kd->arch = *parch;
447 break;
448 }
449 }
450 if (kd->arch == NULL) {
451 _kvm_err(kd, kd->program, "unsupported architecture");
452 goto failed;
453 }
454
455 /*
456 * Non-native kernels require a symbol resolver.
457 */
458 if (!kd->arch->ka_native(kd) && kd->resolve_symbol == NULL) {
459 _kvm_err(kd, kd->program,
460 "non-native kernel requires a symbol resolver");
461 goto failed;
462 }
463
464 /*
465 * Initialize the virtual address translation machinery.
466 */
467 if (kd->arch->ka_initvtop(kd) < 0)
468 goto failed;
469 return (kd);
470 failed:
471 /*
472 * Copy out the error if doing sane error semantics.
473 */
474 if (errout != 0)
475 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX);
476 (void)kvm_close(kd);
477 return (0);
478 }
479
480 kvm_t *
kvm_openfiles(const char * uf,const char * mf,const char * sf __unused,int flag,char * errout)481 kvm_openfiles(const char *uf, const char *mf, const char *sf __unused, int flag,
482 char *errout)
483 {
484 kvm_t *kd;
485
486 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
487 (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX);
488 return (0);
489 }
490 return (_kvm_open(kd, uf, mf, flag, errout));
491 }
492
493 kvm_t *
kvm_open(const char * uf,const char * mf,const char * sf __unused,int flag,const char * errstr)494 kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag,
495 const char *errstr)
496 {
497 kvm_t *kd;
498
499 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
500 if (errstr != NULL)
501 (void)fprintf(stderr, "%s: %s\n",
502 errstr, strerror(errno));
503 return (0);
504 }
505 kd->program = errstr;
506 return (_kvm_open(kd, uf, mf, flag, NULL));
507 }
508
509 kvm_t *
kvm_open2(const char * uf,const char * mf,int flag,char * errout,int (* resolver)(const char *,kvaddr_t *))510 kvm_open2(const char *uf, const char *mf, int flag, char *errout,
511 int (*resolver)(const char *, kvaddr_t *))
512 {
513 kvm_t *kd;
514
515 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
516 (void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX);
517 return (0);
518 }
519 kd->resolve_symbol = resolver;
520 return (_kvm_open(kd, uf, mf, flag, errout));
521 }
522
523 int
kvm_close(kvm_t * kd)524 kvm_close(kvm_t *kd)
525 {
526 int error = 0;
527
528 if (kd->vmst != NULL)
529 kd->arch->ka_freevtop(kd);
530 if (kd->pmfd >= 0)
531 error |= close(kd->pmfd);
532 if (kd->vmfd >= 0)
533 error |= close(kd->vmfd);
534 if (kd->nlfd >= 0)
535 error |= close(kd->nlfd);
536 if (kd->procbase != 0)
537 free((void *)kd->procbase);
538 if (kd->argbuf != 0)
539 free((void *) kd->argbuf);
540 if (kd->argspc != 0)
541 free((void *) kd->argspc);
542 if (kd->argv != 0)
543 free((void *)kd->argv);
544 free((void *)kd);
545
546 return (0);
547 }
548
549 /*
550 * Walk the list of unresolved symbols, generate a new list and prefix the
551 * symbol names, try again, and merge back what we could resolve.
552 */
553 static int
kvm_fdnlist_prefix(kvm_t * kd,struct kvm_nlist * nl,int missing,const char * prefix,kvaddr_t (* validate_fn)(kvm_t *,kvaddr_t))554 kvm_fdnlist_prefix(kvm_t *kd, struct kvm_nlist *nl, int missing,
555 const char *prefix, kvaddr_t (*validate_fn)(kvm_t *, kvaddr_t))
556 {
557 struct kvm_nlist *n, *np, *p;
558 char *cp, *ce;
559 const char *ccp;
560 size_t len;
561 int slen, unresolved;
562
563 /*
564 * Calculate the space we need to malloc for nlist and names.
565 * We are going to store the name twice for later lookups: once
566 * with the prefix and once the unmodified name delmited by \0.
567 */
568 len = 0;
569 unresolved = 0;
570 for (p = nl; p->n_name && p->n_name[0]; ++p) {
571 if (p->n_type != N_UNDF)
572 continue;
573 len += sizeof(struct kvm_nlist) + strlen(prefix) +
574 2 * (strlen(p->n_name) + 1);
575 unresolved++;
576 }
577 if (unresolved == 0)
578 return (unresolved);
579 /* Add space for the terminating nlist entry. */
580 len += sizeof(struct kvm_nlist);
581 unresolved++;
582
583 /* Alloc one chunk for (nlist, [names]) and setup pointers. */
584 n = np = malloc(len);
585 bzero(n, len);
586 if (n == NULL)
587 return (missing);
588 cp = ce = (char *)np;
589 cp += unresolved * sizeof(struct kvm_nlist);
590 ce += len;
591
592 /* Generate shortened nlist with special prefix. */
593 unresolved = 0;
594 for (p = nl; p->n_name && p->n_name[0]; ++p) {
595 if (p->n_type != N_UNDF)
596 continue;
597 *np = *p;
598 /* Save the new\0orig. name so we can later match it again. */
599 slen = snprintf(cp, ce - cp, "%s%s%c%s", prefix,
600 (prefix[0] != '\0' && p->n_name[0] == '_') ?
601 (p->n_name + 1) : p->n_name, '\0', p->n_name);
602 if (slen < 0 || slen >= ce - cp)
603 continue;
604 np->n_name = cp;
605 cp += slen + 1;
606 np++;
607 unresolved++;
608 }
609
610 /* Do lookup on the reduced list. */
611 np = n;
612 unresolved = kvm_fdnlist(kd, np);
613
614 /* Check if we could resolve further symbols and update the list. */
615 if (unresolved >= 0 && unresolved < missing) {
616 /* Find the first freshly resolved entry. */
617 for (; np->n_name && np->n_name[0]; np++)
618 if (np->n_type != N_UNDF)
619 break;
620 /*
621 * The lists are both in the same order,
622 * so we can walk them in parallel.
623 */
624 for (p = nl; np->n_name && np->n_name[0] &&
625 p->n_name && p->n_name[0]; ++p) {
626 if (p->n_type != N_UNDF)
627 continue;
628 /* Skip expanded name and compare to orig. one. */
629 ccp = np->n_name + strlen(np->n_name) + 1;
630 if (strcmp(ccp, p->n_name) != 0)
631 continue;
632 /* Update nlist with new, translated results. */
633 p->n_type = np->n_type;
634 if (validate_fn)
635 p->n_value = (*validate_fn)(kd, np->n_value);
636 else
637 p->n_value = np->n_value;
638 missing--;
639 /* Find next freshly resolved entry. */
640 for (np++; np->n_name && np->n_name[0]; np++)
641 if (np->n_type != N_UNDF)
642 break;
643 }
644 }
645 /* We could assert missing = unresolved here. */
646
647 free(n);
648 return (unresolved);
649 }
650
651 int
_kvm_nlist(kvm_t * kd,struct kvm_nlist * nl,int initialize)652 _kvm_nlist(kvm_t *kd, struct kvm_nlist *nl, int initialize)
653 {
654 struct kvm_nlist *p;
655 int nvalid;
656 struct kld_sym_lookup lookup;
657 int error;
658 const char *prefix = "";
659 char symname[1024]; /* XXX-BZ symbol name length limit? */
660 int tried_vnet, tried_dpcpu;
661
662 /*
663 * If we can't use the kld symbol lookup, revert to the
664 * slow library call.
665 */
666 if (!ISALIVE(kd)) {
667 error = kvm_fdnlist(kd, nl);
668 if (error <= 0) /* Hard error or success. */
669 return (error);
670
671 if (_kvm_vnet_initialized(kd, initialize))
672 error = kvm_fdnlist_prefix(kd, nl, error,
673 VNET_SYMPREFIX, _kvm_vnet_validaddr);
674
675 if (error > 0 && _kvm_dpcpu_initialized(kd, initialize))
676 error = kvm_fdnlist_prefix(kd, nl, error,
677 DPCPU_SYMPREFIX, _kvm_dpcpu_validaddr);
678
679 return (error);
680 }
681
682 /*
683 * We can use the kld lookup syscall. Go through each nlist entry
684 * and look it up with a kldsym(2) syscall.
685 */
686 nvalid = 0;
687 tried_vnet = 0;
688 tried_dpcpu = 0;
689 again:
690 for (p = nl; p->n_name && p->n_name[0]; ++p) {
691 if (p->n_type != N_UNDF)
692 continue;
693
694 lookup.version = sizeof(lookup);
695 lookup.symvalue = 0;
696 lookup.symsize = 0;
697
698 error = snprintf(symname, sizeof(symname), "%s%s", prefix,
699 (prefix[0] != '\0' && p->n_name[0] == '_') ?
700 (p->n_name + 1) : p->n_name);
701 if (error < 0 || error >= (int)sizeof(symname))
702 continue;
703 lookup.symname = symname;
704 if (lookup.symname[0] == '_')
705 lookup.symname++;
706
707 if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) {
708 p->n_type = N_TEXT;
709 if (_kvm_vnet_initialized(kd, initialize) &&
710 strcmp(prefix, VNET_SYMPREFIX) == 0)
711 p->n_value =
712 _kvm_vnet_validaddr(kd, lookup.symvalue);
713 else if (_kvm_dpcpu_initialized(kd, initialize) &&
714 strcmp(prefix, DPCPU_SYMPREFIX) == 0)
715 p->n_value =
716 _kvm_dpcpu_validaddr(kd, lookup.symvalue);
717 else
718 p->n_value = lookup.symvalue;
719 ++nvalid;
720 /* lookup.symsize */
721 }
722 }
723
724 /*
725 * Check the number of entries that weren't found. If they exist,
726 * try again with a prefix for virtualized or DPCPU symbol names.
727 */
728 error = ((p - nl) - nvalid);
729 if (error && _kvm_vnet_initialized(kd, initialize) && !tried_vnet) {
730 tried_vnet = 1;
731 prefix = VNET_SYMPREFIX;
732 goto again;
733 }
734 if (error && _kvm_dpcpu_initialized(kd, initialize) && !tried_dpcpu) {
735 tried_dpcpu = 1;
736 prefix = DPCPU_SYMPREFIX;
737 goto again;
738 }
739
740 /*
741 * Return the number of entries that weren't found. If they exist,
742 * also fill internal error buffer.
743 */
744 error = ((p - nl) - nvalid);
745 if (error)
746 _kvm_syserr(kd, kd->program, "kvm_nlist");
747 return (error);
748 }
749
750 int
kvm_nlist2(kvm_t * kd,struct kvm_nlist * nl)751 kvm_nlist2(kvm_t *kd, struct kvm_nlist *nl)
752 {
753
754 /*
755 * If called via the public interface, permit intialization of
756 * further virtualized modules on demand.
757 */
758 return (_kvm_nlist(kd, nl, 1));
759 }
760
761 int
kvm_nlist(kvm_t * kd,struct nlist * nl)762 kvm_nlist(kvm_t *kd, struct nlist *nl)
763 {
764 struct kvm_nlist *kl;
765 int count, i, nfail;
766
767 /*
768 * Avoid reporting truncated addresses by failing for non-native
769 * cores.
770 */
771 if (!kvm_native(kd)) {
772 _kvm_err(kd, kd->program, "kvm_nlist of non-native vmcore");
773 return (-1);
774 }
775
776 for (count = 0; nl[count].n_name != NULL && nl[count].n_name[0] != '\0';
777 count++)
778 ;
779 if (count == 0)
780 return (0);
781 kl = calloc(count + 1, sizeof(*kl));
782 for (i = 0; i < count; i++)
783 kl[i].n_name = nl[i].n_name;
784 nfail = kvm_nlist2(kd, kl);
785 for (i = 0; i < count; i++) {
786 nl[i].n_type = kl[i].n_type;
787 nl[i].n_other = 0;
788 nl[i].n_desc = 0;
789 nl[i].n_value = kl[i].n_value;
790 }
791 return (nfail);
792 }
793
794 ssize_t
kvm_read(kvm_t * kd,u_long kva,void * buf,size_t len)795 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len)
796 {
797
798 return (kvm_read2(kd, kva, buf, len));
799 }
800
801 ssize_t
kvm_read2(kvm_t * kd,kvaddr_t kva,void * buf,size_t len)802 kvm_read2(kvm_t *kd, kvaddr_t kva, void *buf, size_t len)
803 {
804 int cc;
805 ssize_t cr;
806 off_t pa;
807 char *cp;
808
809 if (ISALIVE(kd)) {
810 /*
811 * We're using /dev/kmem. Just read straight from the
812 * device and let the active kernel do the address translation.
813 */
814 errno = 0;
815 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
816 _kvm_err(kd, 0, "invalid address (0x%jx)",
817 (uintmax_t)kva);
818 return (-1);
819 }
820 cr = read(kd->vmfd, buf, len);
821 if (cr < 0) {
822 _kvm_syserr(kd, 0, "kvm_read");
823 return (-1);
824 } else if (cr < (ssize_t)len)
825 _kvm_err(kd, kd->program, "short read");
826 return (cr);
827 }
828
829 cp = buf;
830 while (len > 0) {
831 cc = kd->arch->ka_kvatop(kd, kva, &pa);
832 if (cc == 0)
833 return (-1);
834 if (cc > (ssize_t)len)
835 cc = len;
836 errno = 0;
837 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
838 _kvm_syserr(kd, 0, _PATH_MEM);
839 break;
840 }
841 cr = read(kd->pmfd, cp, cc);
842 if (cr < 0) {
843 _kvm_syserr(kd, kd->program, "kvm_read");
844 break;
845 }
846 /*
847 * If ka_kvatop returns a bogus value or our core file is
848 * truncated, we might wind up seeking beyond the end of the
849 * core file in which case the read will return 0 (EOF).
850 */
851 if (cr == 0)
852 break;
853 cp += cr;
854 kva += cr;
855 len -= cr;
856 }
857
858 return (cp - (char *)buf);
859 }
860
861 ssize_t
kvm_write(kvm_t * kd,u_long kva,const void * buf,size_t len)862 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len)
863 {
864 int cc;
865
866 if (ISALIVE(kd)) {
867 /*
868 * Just like kvm_read, only we write.
869 */
870 errno = 0;
871 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
872 _kvm_err(kd, 0, "invalid address (%lx)", kva);
873 return (-1);
874 }
875 cc = write(kd->vmfd, buf, len);
876 if (cc < 0) {
877 _kvm_syserr(kd, 0, "kvm_write");
878 return (-1);
879 } else if ((size_t)cc < len)
880 _kvm_err(kd, kd->program, "short write");
881 return (cc);
882 } else {
883 _kvm_err(kd, kd->program,
884 "kvm_write not implemented for dead kernels");
885 return (-1);
886 }
887 /* NOTREACHED */
888 }
889
890 int
kvm_native(kvm_t * kd)891 kvm_native(kvm_t *kd)
892 {
893
894 if (ISALIVE(kd))
895 return (1);
896 return (kd->arch->ka_native(kd));
897 }
898