540 lines
12 KiB
C
540 lines
12 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1989, 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software developed by the Computer Systems
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* Engineering group at Lawrence Berkeley Laboratory under DARPA contract
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* BG 91-66 and contributed to Berkeley.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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__SCCSID("@(#)kvm.c 8.2 (Berkeley) 2/13/94");
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#include <sys/param.h>
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#include <sys/fnv_hash.h>
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#define _WANT_VNET
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#include <sys/user.h>
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#include <sys/linker.h>
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#include <sys/pcpu.h>
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#include <sys/stat.h>
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#include <sys/sysctl.h>
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#include <sys/mman.h>
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#include <stdbool.h>
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#include <net/vnet.h>
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#include <fcntl.h>
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#include <kvm.h>
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#include <limits.h>
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#include <paths.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "kvm_private.h"
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SET_DECLARE(kvm_arch, struct kvm_arch);
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static char _kd_is_null[] = "";
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char *
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kvm_geterr(kvm_t *kd)
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{
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if (kd == NULL)
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return (_kd_is_null);
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return (kd->errbuf);
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}
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static int
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_kvm_read_kernel_ehdr(kvm_t *kd)
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{
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Elf *elf;
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if (elf_version(EV_CURRENT) == EV_NONE) {
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_kvm_err(kd, kd->program, "Unsupported libelf");
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return (-1);
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}
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elf = elf_begin(kd->nlfd, ELF_C_READ, NULL);
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if (elf == NULL) {
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_kvm_err(kd, kd->program, "%s", elf_errmsg(0));
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return (-1);
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}
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if (elf_kind(elf) != ELF_K_ELF) {
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_kvm_err(kd, kd->program, "kernel is not an ELF file");
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return (-1);
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}
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if (gelf_getehdr(elf, &kd->nlehdr) == NULL) {
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_kvm_err(kd, kd->program, "%s", elf_errmsg(0));
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elf_end(elf);
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return (-1);
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}
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elf_end(elf);
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switch (kd->nlehdr.e_ident[EI_DATA]) {
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case ELFDATA2LSB:
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case ELFDATA2MSB:
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return (0);
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default:
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_kvm_err(kd, kd->program,
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"unsupported ELF data encoding for kernel");
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return (-1);
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}
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}
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static kvm_t *
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_kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
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{
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struct kvm_arch **parch;
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struct stat st;
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kd->vmfd = -1;
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kd->pmfd = -1;
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kd->nlfd = -1;
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kd->vmst = NULL;
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kd->procbase = NULL;
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kd->argspc = NULL;
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kd->argv = NULL;
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if (uf == NULL)
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uf = getbootfile();
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else if (strlen(uf) >= MAXPATHLEN) {
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_kvm_err(kd, kd->program, "exec file name too long");
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goto failed;
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}
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if (flag & ~O_RDWR) {
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_kvm_err(kd, kd->program, "bad flags arg");
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goto failed;
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}
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if (mf == NULL)
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mf = _PATH_MEM;
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if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) {
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_kvm_syserr(kd, kd->program, "%s", mf);
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goto failed;
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}
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if (fstat(kd->pmfd, &st) < 0) {
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_kvm_syserr(kd, kd->program, "%s", mf);
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goto failed;
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}
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if (S_ISREG(st.st_mode) && st.st_size <= 0) {
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errno = EINVAL;
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_kvm_syserr(kd, kd->program, "empty file");
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goto failed;
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}
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if (S_ISCHR(st.st_mode)) {
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/*
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* If this is a character special device, then check that
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* it's /dev/mem. If so, open kmem too. (Maybe we should
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* make it work for either /dev/mem or /dev/kmem -- in either
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* case you're working with a live kernel.)
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*/
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if (strcmp(mf, _PATH_DEVNULL) == 0) {
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kd->vmfd = open(_PATH_DEVNULL, O_RDONLY | O_CLOEXEC);
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return (kd);
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} else if (strcmp(mf, _PATH_MEM) == 0) {
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if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) <
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0) {
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_kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
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goto failed;
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}
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return (kd);
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}
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}
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/*
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* This is either a crash dump or a remote live system with its physical
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* memory fully accessible via a special device.
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* Open the namelist fd and determine the architecture.
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*/
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if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) {
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_kvm_syserr(kd, kd->program, "%s", uf);
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goto failed;
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}
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if (_kvm_read_kernel_ehdr(kd) < 0)
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goto failed;
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if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0 ||
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strncmp(mf, _PATH_DEVVMM, strlen(_PATH_DEVVMM)) == 0) {
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kd->rawdump = 1;
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kd->writable = 1;
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}
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SET_FOREACH(parch, kvm_arch) {
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if ((*parch)->ka_probe(kd)) {
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kd->arch = *parch;
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break;
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}
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}
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if (kd->arch == NULL) {
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_kvm_err(kd, kd->program, "unsupported architecture");
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goto failed;
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}
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/*
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* Non-native kernels require a symbol resolver.
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*/
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if (!kd->arch->ka_native(kd) && kd->resolve_symbol == NULL) {
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_kvm_err(kd, kd->program,
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"non-native kernel requires a symbol resolver");
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goto failed;
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}
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/*
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* Initialize the virtual address translation machinery.
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*/
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if (kd->arch->ka_initvtop(kd) < 0)
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goto failed;
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return (kd);
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failed:
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/*
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* Copy out the error if doing sane error semantics.
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*/
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if (errout != NULL)
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strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX);
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(void)kvm_close(kd);
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return (NULL);
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}
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kvm_t *
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kvm_openfiles(const char *uf, const char *mf, const char *sf __unused, int flag,
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char *errout)
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{
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kvm_t *kd;
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if ((kd = calloc(1, sizeof(*kd))) == NULL) {
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if (errout != NULL)
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(void)strlcpy(errout, strerror(errno),
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_POSIX2_LINE_MAX);
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return (NULL);
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}
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return (_kvm_open(kd, uf, mf, flag, errout));
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}
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kvm_t *
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kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag,
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const char *errstr)
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{
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kvm_t *kd;
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if ((kd = calloc(1, sizeof(*kd))) == NULL) {
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if (errstr != NULL)
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(void)fprintf(stderr, "%s: %s\n",
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errstr, strerror(errno));
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return (NULL);
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}
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kd->program = errstr;
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return (_kvm_open(kd, uf, mf, flag, NULL));
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}
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kvm_t *
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kvm_open2(const char *uf, const char *mf, int flag, char *errout,
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int (*resolver)(const char *, kvaddr_t *))
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{
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kvm_t *kd;
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if ((kd = calloc(1, sizeof(*kd))) == NULL) {
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if (errout != NULL)
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(void)strlcpy(errout, strerror(errno),
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_POSIX2_LINE_MAX);
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return (NULL);
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}
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kd->resolve_symbol = resolver;
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return (_kvm_open(kd, uf, mf, flag, errout));
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}
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int
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kvm_close(kvm_t *kd)
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{
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int error = 0;
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if (kd == NULL) {
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errno = EINVAL;
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return (-1);
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}
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if (kd->vmst != NULL)
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kd->arch->ka_freevtop(kd);
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if (kd->pmfd >= 0)
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error |= close(kd->pmfd);
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if (kd->vmfd >= 0)
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error |= close(kd->vmfd);
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if (kd->nlfd >= 0)
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error |= close(kd->nlfd);
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if (kd->procbase != 0)
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free((void *)kd->procbase);
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if (kd->argbuf != 0)
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free((void *) kd->argbuf);
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if (kd->argspc != 0)
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free((void *) kd->argspc);
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if (kd->argv != 0)
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free((void *)kd->argv);
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if (kd->dpcpu_initialized != 0)
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free(kd->dpcpu_off);
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if (kd->pt_map != NULL)
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free(kd->pt_map);
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if (kd->page_map != NULL)
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free(kd->page_map);
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if (kd->sparse_map != MAP_FAILED && kd->sparse_map != NULL)
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munmap(kd->sparse_map, kd->pt_sparse_size);
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free((void *)kd);
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return (error);
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}
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int
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kvm_nlist2(kvm_t *kd, struct kvm_nlist *nl)
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{
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/*
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* If called via the public interface, permit initialization of
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* further virtualized modules on demand.
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*/
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return (_kvm_nlist(kd, nl, 1));
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}
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int
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kvm_nlist(kvm_t *kd, struct nlist *nl)
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{
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struct kvm_nlist *kl;
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int count, i, nfail;
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/*
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* Avoid reporting truncated addresses by failing for non-native
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* cores.
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*/
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if (!kvm_native(kd)) {
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_kvm_err(kd, kd->program, "kvm_nlist of non-native vmcore");
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return (-1);
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}
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for (count = 0; nl[count].n_name != NULL && nl[count].n_name[0] != '\0';
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count++)
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;
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if (count == 0)
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return (0);
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kl = calloc(count + 1, sizeof(*kl));
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if (kl == NULL) {
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_kvm_err(kd, kd->program, "cannot allocate memory");
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return (-1);
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}
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for (i = 0; i < count; i++)
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kl[i].n_name = nl[i].n_name;
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nfail = kvm_nlist2(kd, kl);
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for (i = 0; i < count; i++) {
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nl[i].n_type = kl[i].n_type;
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nl[i].n_other = 0;
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nl[i].n_desc = 0;
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nl[i].n_value = kl[i].n_value;
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}
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free(kl);
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return (nfail);
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}
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ssize_t
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kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len)
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{
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return (kvm_read2(kd, kva, buf, len));
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}
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ssize_t
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kvm_read2(kvm_t *kd, kvaddr_t kva, void *buf, size_t len)
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{
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int cc;
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ssize_t cr;
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off_t pa;
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char *cp;
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if (ISALIVE(kd)) {
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/*
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* We're using /dev/kmem. Just read straight from the
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* device and let the active kernel do the address translation.
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*/
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errno = 0;
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if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
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_kvm_err(kd, 0, "invalid address (0x%jx)",
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(uintmax_t)kva);
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return (-1);
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}
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cr = read(kd->vmfd, buf, len);
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if (cr < 0) {
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_kvm_syserr(kd, 0, "kvm_read");
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return (-1);
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} else if (cr < (ssize_t)len)
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_kvm_err(kd, kd->program, "short read");
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return (cr);
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}
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cp = buf;
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while (len > 0) {
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cc = kd->arch->ka_kvatop(kd, kva, &pa);
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if (cc == 0)
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return (-1);
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if (cc > (ssize_t)len)
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cc = len;
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errno = 0;
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if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
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_kvm_syserr(kd, 0, _PATH_MEM);
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break;
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}
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cr = read(kd->pmfd, cp, cc);
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if (cr < 0) {
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_kvm_syserr(kd, kd->program, "kvm_read");
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break;
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}
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/*
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* If ka_kvatop returns a bogus value or our core file is
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* truncated, we might wind up seeking beyond the end of the
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* core file in which case the read will return 0 (EOF).
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*/
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if (cr == 0)
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break;
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cp += cr;
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kva += cr;
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len -= cr;
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}
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return (cp - (char *)buf);
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}
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ssize_t
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kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len)
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{
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int cc;
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ssize_t cw;
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off_t pa;
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const char *cp;
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if (!ISALIVE(kd) && !kd->writable) {
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_kvm_err(kd, kd->program,
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"kvm_write not implemented for dead kernels");
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return (-1);
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}
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if (ISALIVE(kd)) {
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/*
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* Just like kvm_read, only we write.
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*/
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errno = 0;
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if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) {
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_kvm_err(kd, 0, "invalid address (%lx)", kva);
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return (-1);
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}
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cc = write(kd->vmfd, buf, len);
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if (cc < 0) {
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_kvm_syserr(kd, 0, "kvm_write");
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return (-1);
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} else if ((size_t)cc < len)
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_kvm_err(kd, kd->program, "short write");
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return (cc);
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}
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cp = buf;
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while (len > 0) {
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cc = kd->arch->ka_kvatop(kd, kva, &pa);
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if (cc == 0)
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return (-1);
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if (cc > (ssize_t)len)
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cc = len;
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errno = 0;
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if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
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_kvm_syserr(kd, 0, _PATH_MEM);
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break;
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}
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cw = write(kd->pmfd, cp, cc);
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if (cw < 0) {
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_kvm_syserr(kd, kd->program, "kvm_write");
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break;
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}
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/*
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* If ka_kvatop returns a bogus value or our core file is
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* truncated, we might wind up seeking beyond the end of the
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* core file in which case the read will return 0 (EOF).
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*/
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if (cw == 0)
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break;
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cp += cw;
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kva += cw;
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len -= cw;
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}
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return (cp - (const char *)buf);
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}
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int
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kvm_native(kvm_t *kd)
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{
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if (ISALIVE(kd))
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return (1);
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return (kd->arch->ka_native(kd));
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}
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int
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kvm_walk_pages(kvm_t *kd, kvm_walk_pages_cb_t *cb, void *closure)
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{
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if (kd->arch->ka_walk_pages == NULL)
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return (0);
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return (kd->arch->ka_walk_pages(kd, cb, closure));
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}
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kssize_t
|
|
kvm_kerndisp(kvm_t *kd)
|
|
{
|
|
unsigned long kernbase, rel_kernbase;
|
|
size_t kernbase_len = sizeof(kernbase);
|
|
size_t rel_kernbase_len = sizeof(rel_kernbase);
|
|
|
|
if (ISALIVE(kd)) {
|
|
if (sysctlbyname("kern.base_address", &kernbase,
|
|
&kernbase_len, NULL, 0) == -1) {
|
|
_kvm_syserr(kd, kd->program,
|
|
"failed to get kernel base address");
|
|
return (0);
|
|
}
|
|
if (sysctlbyname("kern.relbase_address", &rel_kernbase,
|
|
&rel_kernbase_len, NULL, 0) == -1) {
|
|
_kvm_syserr(kd, kd->program,
|
|
"failed to get relocated kernel base address");
|
|
return (0);
|
|
}
|
|
return (rel_kernbase - kernbase);
|
|
}
|
|
|
|
if (kd->arch->ka_kerndisp == NULL)
|
|
return (0);
|
|
|
|
return (kd->arch->ka_kerndisp(kd));
|
|
}
|