diff options
Diffstat (limited to 'lib/libkvm/kvm.c')
| -rw-r--r-- | lib/libkvm/kvm.c | 536 |
1 files changed, 536 insertions, 0 deletions
diff --git a/lib/libkvm/kvm.c b/lib/libkvm/kvm.c new file mode 100644 index 000000000000..4ed48951a327 --- /dev/null +++ b/lib/libkvm/kvm.c @@ -0,0 +1,536 @@ +/*- + * SPDX-License-Identifier: BSD-3-Clause + * + * Copyright (c) 1989, 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software developed by the Computer Systems + * Engineering group at Lawrence Berkeley Laboratory under DARPA contract + * BG 91-66 and contributed to Berkeley. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + + +#include <sys/param.h> +#include <sys/fnv_hash.h> + +#define _WANT_VNET + +#include <sys/user.h> +#include <sys/linker.h> +#include <sys/pcpu.h> +#include <sys/stat.h> +#include <sys/sysctl.h> +#include <sys/mman.h> + +#include <stdbool.h> +#include <net/vnet.h> + +#include <fcntl.h> +#include <kvm.h> +#include <limits.h> +#include <paths.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "kvm_private.h" + +SET_DECLARE(kvm_arch, struct kvm_arch); + +static char _kd_is_null[] = ""; + +char * +kvm_geterr(kvm_t *kd) +{ + + if (kd == NULL) + return (_kd_is_null); + return (kd->errbuf); +} + +static int +_kvm_read_kernel_ehdr(kvm_t *kd) +{ + Elf *elf; + + if (elf_version(EV_CURRENT) == EV_NONE) { + _kvm_err(kd, kd->program, "Unsupported libelf"); + return (-1); + } + elf = elf_begin(kd->nlfd, ELF_C_READ, NULL); + if (elf == NULL) { + _kvm_err(kd, kd->program, "%s", elf_errmsg(0)); + return (-1); + } + if (elf_kind(elf) != ELF_K_ELF) { + _kvm_err(kd, kd->program, "kernel is not an ELF file"); + return (-1); + } + if (gelf_getehdr(elf, &kd->nlehdr) == NULL) { + _kvm_err(kd, kd->program, "%s", elf_errmsg(0)); + elf_end(elf); + return (-1); + } + elf_end(elf); + + switch (kd->nlehdr.e_ident[EI_DATA]) { + case ELFDATA2LSB: + case ELFDATA2MSB: + return (0); + default: + _kvm_err(kd, kd->program, + "unsupported ELF data encoding for kernel"); + return (-1); + } +} + +static kvm_t * +_kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout) +{ + struct kvm_arch **parch; + struct stat st; + + kd->vmfd = -1; + kd->pmfd = -1; + kd->nlfd = -1; + kd->vmst = NULL; + kd->procbase = NULL; + kd->argspc = NULL; + kd->argv = NULL; + + if (uf == NULL) + uf = getbootfile(); + else if (strlen(uf) >= MAXPATHLEN) { + _kvm_err(kd, kd->program, "exec file name too long"); + goto failed; + } + if (flag & ~O_RDWR) { + _kvm_err(kd, kd->program, "bad flags arg"); + goto failed; + } + if (mf == NULL) + mf = _PATH_MEM; + + if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) { + _kvm_syserr(kd, kd->program, "%s", mf); + goto failed; + } + if (fstat(kd->pmfd, &st) < 0) { + _kvm_syserr(kd, kd->program, "%s", mf); + goto failed; + } + if (S_ISREG(st.st_mode) && st.st_size <= 0) { + errno = EINVAL; + _kvm_syserr(kd, kd->program, "empty file"); + goto failed; + } + if (S_ISCHR(st.st_mode)) { + /* + * If this is a character special device, then check that + * it's /dev/mem. If so, open kmem too. (Maybe we should + * make it work for either /dev/mem or /dev/kmem -- in either + * case you're working with a live kernel.) + */ + if (strcmp(mf, _PATH_DEVNULL) == 0) { + kd->vmfd = open(_PATH_DEVNULL, O_RDONLY | O_CLOEXEC); + return (kd); + } else if (strcmp(mf, _PATH_MEM) == 0) { + if ((kd->vmfd = open(_PATH_KMEM, flag | O_CLOEXEC)) < + 0) { + _kvm_syserr(kd, kd->program, "%s", _PATH_KMEM); + goto failed; + } + return (kd); + } + } + + /* + * This is either a crash dump or a remote live system with its physical + * memory fully accessible via a special device. + * Open the namelist fd and determine the architecture. + */ + if ((kd->nlfd = open(uf, O_RDONLY | O_CLOEXEC, 0)) < 0) { + _kvm_syserr(kd, kd->program, "%s", uf); + goto failed; + } + if (_kvm_read_kernel_ehdr(kd) < 0) + goto failed; + if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0 || + strncmp(mf, _PATH_DEVVMM, strlen(_PATH_DEVVMM)) == 0) { + kd->rawdump = 1; + kd->writable = 1; + } + SET_FOREACH(parch, kvm_arch) { + if ((*parch)->ka_probe(kd)) { + kd->arch = *parch; + break; + } + } + if (kd->arch == NULL) { + _kvm_err(kd, kd->program, "unsupported architecture"); + goto failed; + } + + /* + * Non-native kernels require a symbol resolver. + */ + if (!kd->arch->ka_native(kd) && kd->resolve_symbol == NULL) { + _kvm_err(kd, kd->program, + "non-native kernel requires a symbol resolver"); + goto failed; + } + + /* + * Initialize the virtual address translation machinery. + */ + if (kd->arch->ka_initvtop(kd) < 0) + goto failed; + return (kd); +failed: + /* + * Copy out the error if doing sane error semantics. + */ + if (errout != NULL) + strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX); + (void)kvm_close(kd); + return (NULL); +} + +kvm_t * +kvm_openfiles(const char *uf, const char *mf, const char *sf __unused, int flag, + char *errout) +{ + kvm_t *kd; + + if ((kd = calloc(1, sizeof(*kd))) == NULL) { + if (errout != NULL) + (void)strlcpy(errout, strerror(errno), + _POSIX2_LINE_MAX); + return (NULL); + } + return (_kvm_open(kd, uf, mf, flag, errout)); +} + +kvm_t * +kvm_open(const char *uf, const char *mf, const char *sf __unused, int flag, + const char *errstr) +{ + kvm_t *kd; + + if ((kd = calloc(1, sizeof(*kd))) == NULL) { + if (errstr != NULL) + (void)fprintf(stderr, "%s: %s\n", + errstr, strerror(errno)); + return (NULL); + } + kd->program = errstr; + return (_kvm_open(kd, uf, mf, flag, NULL)); +} + +kvm_t * +kvm_open2(const char *uf, const char *mf, int flag, char *errout, + int (*resolver)(const char *, kvaddr_t *)) +{ + kvm_t *kd; + + if ((kd = calloc(1, sizeof(*kd))) == NULL) { + if (errout != NULL) + (void)strlcpy(errout, strerror(errno), + _POSIX2_LINE_MAX); + return (NULL); + } + kd->resolve_symbol = resolver; + return (_kvm_open(kd, uf, mf, flag, errout)); +} + +int +kvm_close(kvm_t *kd) +{ + int error = 0; + + if (kd == NULL) { + errno = EINVAL; + return (-1); + } + if (kd->vmst != NULL) + kd->arch->ka_freevtop(kd); + if (kd->pmfd >= 0) + error |= close(kd->pmfd); + if (kd->vmfd >= 0) + error |= close(kd->vmfd); + if (kd->nlfd >= 0) + error |= close(kd->nlfd); + if (kd->procbase != 0) + free((void *)kd->procbase); + if (kd->argbuf != 0) + free((void *) kd->argbuf); + if (kd->argspc != 0) + free((void *) kd->argspc); + if (kd->argv != 0) + free((void *)kd->argv); + if (kd->dpcpu_initialized != 0) + free(kd->dpcpu_off); + if (kd->pt_map != NULL) + free(kd->pt_map); + if (kd->page_map != NULL) + free(kd->page_map); + if (kd->sparse_map != MAP_FAILED && kd->sparse_map != NULL) + munmap(kd->sparse_map, kd->pt_sparse_size); + free((void *)kd); + + return (error); +} + +int +kvm_nlist2(kvm_t *kd, struct kvm_nlist *nl) +{ + + /* + * If called via the public interface, permit initialization of + * further virtualized modules on demand. + */ + return (_kvm_nlist(kd, nl, 1)); +} + +int +kvm_nlist(kvm_t *kd, struct nlist *nl) +{ + struct kvm_nlist *kl; + int count, i, nfail; + + /* + * Avoid reporting truncated addresses by failing for non-native + * cores. + */ + if (!kvm_native(kd)) { + _kvm_err(kd, kd->program, "kvm_nlist of non-native vmcore"); + return (-1); + } + + for (count = 0; nl[count].n_name != NULL && nl[count].n_name[0] != '\0'; + count++) + ; + if (count == 0) + return (0); + kl = calloc(count + 1, sizeof(*kl)); + if (kl == NULL) { + _kvm_err(kd, kd->program, "cannot allocate memory"); + return (-1); + } + for (i = 0; i < count; i++) + kl[i].n_name = nl[i].n_name; + nfail = kvm_nlist2(kd, kl); + for (i = 0; i < count; i++) { + nl[i].n_type = kl[i].n_type; + nl[i].n_other = 0; + nl[i].n_desc = 0; + nl[i].n_value = kl[i].n_value; + } + free(kl); + return (nfail); +} + +ssize_t +kvm_read(kvm_t *kd, u_long kva, void *buf, size_t len) +{ + + return (kvm_read2(kd, kva, buf, len)); +} + +ssize_t +kvm_read2(kvm_t *kd, kvaddr_t kva, void *buf, size_t len) +{ + int cc; + ssize_t cr; + off_t pa; + char *cp; + + if (ISALIVE(kd)) { + /* + * We're using /dev/kmem. Just read straight from the + * device and let the active kernel do the address translation. + */ + errno = 0; + if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { + _kvm_err(kd, 0, "invalid address (0x%jx)", + (uintmax_t)kva); + return (-1); + } + cr = read(kd->vmfd, buf, len); + if (cr < 0) { + _kvm_syserr(kd, 0, "kvm_read"); + return (-1); + } else if (cr < (ssize_t)len) + _kvm_err(kd, kd->program, "short read"); + return (cr); + } + + cp = buf; + while (len > 0) { + cc = kd->arch->ka_kvatop(kd, kva, &pa); + if (cc == 0) + return (-1); + if (cc > (ssize_t)len) + cc = len; + errno = 0; + if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { + _kvm_syserr(kd, 0, _PATH_MEM); + break; + } + cr = read(kd->pmfd, cp, cc); + if (cr < 0) { + _kvm_syserr(kd, kd->program, "kvm_read"); + break; + } + /* + * If ka_kvatop returns a bogus value or our core file is + * truncated, we might wind up seeking beyond the end of the + * core file in which case the read will return 0 (EOF). + */ + if (cr == 0) + break; + cp += cr; + kva += cr; + len -= cr; + } + + return (cp - (char *)buf); +} + +ssize_t +kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len) +{ + int cc; + ssize_t cw; + off_t pa; + const char *cp; + + if (!ISALIVE(kd) && !kd->writable) { + _kvm_err(kd, kd->program, + "kvm_write not implemented for dead kernels"); + return (-1); + } + + if (ISALIVE(kd)) { + /* + * Just like kvm_read, only we write. + */ + errno = 0; + if (lseek(kd->vmfd, (off_t)kva, 0) == -1 && errno != 0) { + _kvm_err(kd, 0, "invalid address (%lx)", kva); + return (-1); + } + cc = write(kd->vmfd, buf, len); + if (cc < 0) { + _kvm_syserr(kd, 0, "kvm_write"); + return (-1); + } else if ((size_t)cc < len) + _kvm_err(kd, kd->program, "short write"); + return (cc); + } + + cp = buf; + while (len > 0) { + cc = kd->arch->ka_kvatop(kd, kva, &pa); + if (cc == 0) + return (-1); + if (cc > (ssize_t)len) + cc = len; + errno = 0; + if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) { + _kvm_syserr(kd, 0, _PATH_MEM); + break; + } + cw = write(kd->pmfd, cp, cc); + if (cw < 0) { + _kvm_syserr(kd, kd->program, "kvm_write"); + break; + } + /* + * If ka_kvatop returns a bogus value or our core file is + * truncated, we might wind up seeking beyond the end of the + * core file in which case the read will return 0 (EOF). + */ + if (cw == 0) + break; + cp += cw; + kva += cw; + len -= cw; + } + + return (cp - (const char *)buf); +} + +int +kvm_native(kvm_t *kd) +{ + + if (ISALIVE(kd)) + return (1); + return (kd->arch->ka_native(kd)); +} + +int +kvm_walk_pages(kvm_t *kd, kvm_walk_pages_cb_t *cb, void *closure) +{ + + if (kd->arch->ka_walk_pages == NULL) + return (0); + + return (kd->arch->ka_walk_pages(kd, cb, closure)); +} + +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)); +} |