2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1989, 1992, 1993
5 * The Regents of the University of California. All rights reserved.
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.
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12 * modification, are permitted provided that the following conditions
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15 * notice, this list of conditions and the following disclaimer.
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36 #include <sys/cdefs.h>
37 __SCCSID("@(#)kvm.c 8.2 (Berkeley) 2/13/94");
39 #include <sys/param.h>
40 #include <sys/fnv_hash.h>
45 #include <sys/linker.h>
48 #include <sys/sysctl.h>
64 #include "kvm_private.h"
66 SET_DECLARE(kvm_arch, struct kvm_arch);
68 static char _kd_is_null[] = "";
80 _kvm_read_kernel_ehdr(kvm_t *kd)
84 if (elf_version(EV_CURRENT) == EV_NONE) {
85 _kvm_err(kd, kd->program, "Unsupported libelf");
88 elf = elf_begin(kd->nlfd, ELF_C_READ, NULL);
90 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
93 if (elf_kind(elf) != ELF_K_ELF) {
94 _kvm_err(kd, kd->program, "kernel is not an ELF file");
97 if (gelf_getehdr(elf, &kd->nlehdr) == NULL) {
98 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
104 switch (kd->nlehdr.e_ident[EI_DATA]) {
109 _kvm_err(kd, kd->program,
110 "unsupported ELF data encoding for kernel");
116 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
118 struct kvm_arch **parch;
131 else if (strlen(uf) >= MAXPATHLEN) {
132 _kvm_err(kd, kd->program, "exec file name too long");
135 if (flag & ~O_RDWR) {
136 _kvm_err(kd, kd->program, "bad flags arg");
142 if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) {
143 _kvm_syserr(kd, kd->program, "%s", mf);
146 if (fstat(kd->pmfd, &st) < 0) {
147 _kvm_syserr(kd, kd->program, "%s", mf);
150 if (S_ISREG(st.st_mode) && st.st_size <= 0) {
152 _kvm_syserr(kd, kd->program, "empty file");
155 if (S_ISCHR(st.st_mode)) {
157 * If this is a character special device, then check that
158 * it's /dev/mem. If so, open kmem too. (Maybe we should
159 * make it work for either /dev/mem or /dev/kmem -- in either
160 * case you're working with a live kernel.)
162 if (strcmp(mf, _PATH_DEVNULL) == 0) {
163 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY | O_CLOEXEC);
165 } else if (strcmp(mf, _PATH_MEM) == 0) {
166 if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) <
168 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
176 * This is either a crash dump or a remote live system with its physical
177 * memory fully accessible via a special device.
178 * Open the namelist fd and determine the architecture.
180 if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) {
181 _kvm_syserr(kd, kd->program, "%s", uf);
184 if (_kvm_read_kernel_ehdr(kd) < 0)
186 if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0 ||
187 strncmp(mf, _PATH_DEVVMM, strlen(_PATH_DEVVMM)) == 0) {
191 SET_FOREACH(parch, kvm_arch) {
192 if ((*parch)->ka_probe(kd)) {
197 if (kd->arch == NULL) {
198 _kvm_err(kd, kd->program, "unsupported architecture");
203 * Non-native kernels require a symbol resolver.
205 if (!kd->arch->ka_native(kd) && kd->resolve_symbol == NULL) {
206 _kvm_err(kd, kd->program,
207 "non-native kernel requires a symbol resolver");
212 * Initialize the virtual address translation machinery.
214 if (kd->arch->ka_initvtop(kd) < 0)
219 * Copy out the error if doing sane error semantics.
222 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX);
228 kvm_openfiles(const char *uf, const char *mf, const char *sf __unused, int flag,
233 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
235 (void)strlcpy(errout, strerror(errno),
239 return (_kvm_open(kd, uf, mf, flag, errout));
243 kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag,
248 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
250 (void)fprintf(stderr, "%s: %s\n",
251 errstr, strerror(errno));
254 kd->program = errstr;
255 return (_kvm_open(kd, uf, mf, flag, NULL));
259 kvm_open2(const char *uf, const char *mf, int flag, char *errout,
260 int (*resolver)(const char *, kvaddr_t *))
264 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
266 (void)strlcpy(errout, strerror(errno),
270 kd->resolve_symbol = resolver;
271 return (_kvm_open(kd, uf, mf, flag, errout));
283 if (kd->vmst != NULL)
284 kd->arch->ka_freevtop(kd);
286 error |= close(kd->pmfd);
288 error |= close(kd->vmfd);
290 error |= close(kd->nlfd);
291 if (kd->procbase != 0)
292 free((void *)kd->procbase);
294 free((void *) kd->argbuf);
296 free((void *) kd->argspc);
298 free((void *)kd->argv);
299 if (kd->dpcpu_initialized != 0)
301 if (kd->pt_map != NULL)
303 if (kd->page_map != NULL)
305 if (kd->sparse_map != MAP_FAILED && kd->sparse_map != NULL)
306 munmap(kd->sparse_map, kd->pt_sparse_size);
313 kvm_nlist2(kvm_t *kd, struct kvm_nlist *nl)
317 * If called via the public interface, permit initialization of
318 * further virtualized modules on demand.
320 return (_kvm_nlist(kd, nl, 1));
324 kvm_nlist(kvm_t *kd, struct nlist *nl)
326 struct kvm_nlist *kl;
330 * Avoid reporting truncated addresses by failing for non-native
333 if (!kvm_native(kd)) {
334 _kvm_err(kd, kd->program, "kvm_nlist of non-native vmcore");
338 for (count = 0; nl[count].n_name != NULL && nl[count].n_name[0] != '\0';
343 kl = calloc(count + 1, sizeof(*kl));
345 _kvm_err(kd, kd->program, "cannot allocate memory");
348 for (i = 0; i < count; i++)
349 kl[i].n_name = nl[i].n_name;
350 nfail = kvm_nlist2(kd, kl);
351 for (i = 0; i < count; i++) {
352 nl[i].n_type = kl[i].n_type;
355 nl[i].n_value = kl[i].n_value;
362 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len)
365 return (kvm_read2(kd, kva, buf, len));
369 kvm_read2(kvm_t *kd, kvaddr_t kva, void *buf, size_t len)
378 * We're using /dev/kmem. Just read straight from the
379 * device and let the active kernel do the address translation.
382 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
383 _kvm_err(kd, 0, "invalid address (0x%jx)",
387 cr = read(kd->vmfd, buf, len);
389 _kvm_syserr(kd, 0, "kvm_read");
391 } else if (cr < (ssize_t)len)
392 _kvm_err(kd, kd->program, "short read");
398 cc = kd->arch->ka_kvatop(kd, kva, &pa);
401 if (cc > (ssize_t)len)
404 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
405 _kvm_syserr(kd, 0, _PATH_MEM);
408 cr = read(kd->pmfd, cp, cc);
410 _kvm_syserr(kd, kd->program, "kvm_read");
414 * If ka_kvatop returns a bogus value or our core file is
415 * truncated, we might wind up seeking beyond the end of the
416 * core file in which case the read will return 0 (EOF).
425 return (cp - (char *)buf);
429 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len)
436 if (!ISALIVE(kd) && !kd->writable) {
437 _kvm_err(kd, kd->program,
438 "kvm_write not implemented for dead kernels");
444 * Just like kvm_read, only we write.
447 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
448 _kvm_err(kd, 0, "invalid address (%lx)", kva);
451 cc = write(kd->vmfd, buf, len);
453 _kvm_syserr(kd, 0, "kvm_write");
455 } else if ((size_t)cc < len)
456 _kvm_err(kd, kd->program, "short write");
462 cc = kd->arch->ka_kvatop(kd, kva, &pa);
465 if (cc > (ssize_t)len)
468 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
469 _kvm_syserr(kd, 0, _PATH_MEM);
472 cw = write(kd->pmfd, cp, cc);
474 _kvm_syserr(kd, kd->program, "kvm_write");
478 * If ka_kvatop returns a bogus value or our core file is
479 * truncated, we might wind up seeking beyond the end of the
480 * core file in which case the read will return 0 (EOF).
489 return (cp - (const char *)buf);
493 kvm_native(kvm_t *kd)
498 return (kd->arch->ka_native(kd));
502 kvm_walk_pages(kvm_t *kd, kvm_walk_pages_cb_t *cb, void *closure)
505 if (kd->arch->ka_walk_pages == NULL)
508 return (kd->arch->ka_walk_pages(kd, cb, closure));
512 kvm_kerndisp(kvm_t *kd)
514 unsigned long kernbase, rel_kernbase;
515 size_t kernbase_len = sizeof(kernbase);
516 size_t rel_kernbase_len = sizeof(rel_kernbase);
519 if (sysctlbyname("kern.base_address", &kernbase,
520 &kernbase_len, NULL, 0) == -1) {
521 _kvm_syserr(kd, kd->program,
522 "failed to get kernel base address");
525 if (sysctlbyname("kern.relbase_address", &rel_kernbase,
526 &rel_kernbase_len, NULL, 0) == -1) {
527 _kvm_syserr(kd, kd->program,
528 "failed to get relocated kernel base address");
531 return (rel_kernbase - kernbase);
534 if (kd->arch->ka_kerndisp == NULL)
537 return (kd->arch->ka_kerndisp(kd));