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
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
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20 * may be used to endorse or promote products derived from this software
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36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 __SCCSID("@(#)kvm.c 8.2 (Berkeley) 2/13/94");
40 #include <sys/param.h>
41 #include <sys/fnv_hash.h>
46 #include <sys/linker.h>
63 #include "kvm_private.h"
65 SET_DECLARE(kvm_arch, struct kvm_arch);
67 static char _kd_is_null[] = "";
79 _kvm_read_kernel_ehdr(kvm_t *kd)
83 if (elf_version(EV_CURRENT) == EV_NONE) {
84 _kvm_err(kd, kd->program, "Unsupported libelf");
87 elf = elf_begin(kd->nlfd, ELF_C_READ, NULL);
89 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
92 if (elf_kind(elf) != ELF_K_ELF) {
93 _kvm_err(kd, kd->program, "kernel is not an ELF file");
96 if (gelf_getehdr(elf, &kd->nlehdr) == NULL) {
97 _kvm_err(kd, kd->program, "%s", elf_errmsg(0));
103 switch (kd->nlehdr.e_ident[EI_DATA]) {
108 _kvm_err(kd, kd->program,
109 "unsupported ELF data encoding for kernel");
115 _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
117 struct kvm_arch **parch;
130 else if (strlen(uf) >= MAXPATHLEN) {
131 _kvm_err(kd, kd->program, "exec file name too long");
134 if (flag & ~O_RDWR) {
135 _kvm_err(kd, kd->program, "bad flags arg");
141 if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) {
142 _kvm_syserr(kd, kd->program, "%s", mf);
145 if (fstat(kd->pmfd, &st) < 0) {
146 _kvm_syserr(kd, kd->program, "%s", mf);
149 if (S_ISREG(st.st_mode) && st.st_size <= 0) {
151 _kvm_syserr(kd, kd->program, "empty file");
154 if (S_ISCHR(st.st_mode)) {
156 * If this is a character special device, then check that
157 * it's /dev/mem. If so, open kmem too. (Maybe we should
158 * make it work for either /dev/mem or /dev/kmem -- in either
159 * case you're working with a live kernel.)
161 if (strcmp(mf, _PATH_DEVNULL) == 0) {
162 kd->vmfd = open(_PATH_DEVNULL, O_RDONLY | O_CLOEXEC);
164 } else if (strcmp(mf, _PATH_MEM) == 0) {
165 if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) <
167 _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
175 * This is either a crash dump or a remote live system with its physical
176 * memory fully accessible via a special device.
177 * Open the namelist fd and determine the architecture.
179 if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) {
180 _kvm_syserr(kd, kd->program, "%s", uf);
183 if (_kvm_read_kernel_ehdr(kd) < 0)
185 if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0 ||
186 strncmp(mf, _PATH_DEVVMM, strlen(_PATH_DEVVMM)) == 0) {
190 SET_FOREACH(parch, kvm_arch) {
191 if ((*parch)->ka_probe(kd)) {
196 if (kd->arch == NULL) {
197 _kvm_err(kd, kd->program, "unsupported architecture");
202 * Non-native kernels require a symbol resolver.
204 if (!kd->arch->ka_native(kd) && kd->resolve_symbol == NULL) {
205 _kvm_err(kd, kd->program,
206 "non-native kernel requires a symbol resolver");
211 * Initialize the virtual address translation machinery.
213 if (kd->arch->ka_initvtop(kd) < 0)
218 * Copy out the error if doing sane error semantics.
221 strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX);
227 kvm_openfiles(const char *uf, const char *mf, const char *sf __unused, int flag,
232 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
234 (void)strlcpy(errout, strerror(errno),
238 return (_kvm_open(kd, uf, mf, flag, errout));
242 kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag,
247 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
249 (void)fprintf(stderr, "%s: %s\n",
250 errstr, strerror(errno));
253 kd->program = errstr;
254 return (_kvm_open(kd, uf, mf, flag, NULL));
258 kvm_open2(const char *uf, const char *mf, int flag, char *errout,
259 int (*resolver)(const char *, kvaddr_t *))
263 if ((kd = calloc(1, sizeof(*kd))) == NULL) {
265 (void)strlcpy(errout, strerror(errno),
269 kd->resolve_symbol = resolver;
270 return (_kvm_open(kd, uf, mf, flag, errout));
282 if (kd->vmst != NULL)
283 kd->arch->ka_freevtop(kd);
285 error |= close(kd->pmfd);
287 error |= close(kd->vmfd);
289 error |= close(kd->nlfd);
290 if (kd->procbase != 0)
291 free((void *)kd->procbase);
293 free((void *) kd->argbuf);
295 free((void *) kd->argspc);
297 free((void *)kd->argv);
298 if (kd->pt_map != NULL)
300 if (kd->page_map != NULL)
302 if (kd->sparse_map != MAP_FAILED)
303 munmap(kd->sparse_map, kd->pt_sparse_size);
310 kvm_nlist2(kvm_t *kd, struct kvm_nlist *nl)
314 * If called via the public interface, permit initialization of
315 * further virtualized modules on demand.
317 return (_kvm_nlist(kd, nl, 1));
321 kvm_nlist(kvm_t *kd, struct nlist *nl)
323 struct kvm_nlist *kl;
327 * Avoid reporting truncated addresses by failing for non-native
330 if (!kvm_native(kd)) {
331 _kvm_err(kd, kd->program, "kvm_nlist of non-native vmcore");
335 for (count = 0; nl[count].n_name != NULL && nl[count].n_name[0] != '\0';
340 kl = calloc(count + 1, sizeof(*kl));
341 for (i = 0; i < count; i++)
342 kl[i].n_name = nl[i].n_name;
343 nfail = kvm_nlist2(kd, kl);
344 for (i = 0; i < count; i++) {
345 nl[i].n_type = kl[i].n_type;
348 nl[i].n_value = kl[i].n_value;
354 kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len)
357 return (kvm_read2(kd, kva, buf, len));
361 kvm_read2(kvm_t *kd, kvaddr_t kva, void *buf, size_t len)
370 * We're using /dev/kmem. Just read straight from the
371 * device and let the active kernel do the address translation.
374 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
375 _kvm_err(kd, 0, "invalid address (0x%jx)",
379 cr = read(kd->vmfd, buf, len);
381 _kvm_syserr(kd, 0, "kvm_read");
383 } else if (cr < (ssize_t)len)
384 _kvm_err(kd, kd->program, "short read");
390 cc = kd->arch->ka_kvatop(kd, kva, &pa);
393 if (cc > (ssize_t)len)
396 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
397 _kvm_syserr(kd, 0, _PATH_MEM);
400 cr = read(kd->pmfd, cp, cc);
402 _kvm_syserr(kd, kd->program, "kvm_read");
406 * If ka_kvatop returns a bogus value or our core file is
407 * truncated, we might wind up seeking beyond the end of the
408 * core file in which case the read will return 0 (EOF).
417 return (cp - (char *)buf);
421 kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len)
428 if (!ISALIVE(kd) && !kd->writable) {
429 _kvm_err(kd, kd->program,
430 "kvm_write not implemented for dead kernels");
436 * Just like kvm_read, only we write.
439 if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
440 _kvm_err(kd, 0, "invalid address (%lx)", kva);
443 cc = write(kd->vmfd, buf, len);
445 _kvm_syserr(kd, 0, "kvm_write");
447 } else if ((size_t)cc < len)
448 _kvm_err(kd, kd->program, "short write");
454 cc = kd->arch->ka_kvatop(kd, kva, &pa);
457 if (cc > (ssize_t)len)
460 if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
461 _kvm_syserr(kd, 0, _PATH_MEM);
464 cw = write(kd->pmfd, cp, cc);
466 _kvm_syserr(kd, kd->program, "kvm_write");
470 * If ka_kvatop returns a bogus value or our core file is
471 * truncated, we might wind up seeking beyond the end of the
472 * core file in which case the read will return 0 (EOF).
481 return (cp - (const char *)buf);
485 kvm_native(kvm_t *kd)
490 return (kd->arch->ka_native(kd));
494 kvm_walk_pages(kvm_t *kd, kvm_walk_pages_cb_t *cb, void *closure)
497 if (kd->arch->ka_walk_pages == NULL)
500 return (kd->arch->ka_walk_pages(kd, cb, closure));