freebsd-skq/lib/libkvm/kvm.c
2016-05-01 19:37:33 +00:00

902 lines
21 KiB
C

/*-
* 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.
* 4. 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/cdefs.h>
__FBSDID("$FreeBSD$");
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)kvm.c 8.2 (Berkeley) 2/13/94";
#endif
#endif /* LIBC_SCCS and not lint */
#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 <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);
/* from src/lib/libc/gen/nlist.c */
int __fdnlist(int, struct nlist *);
static int
kvm_fdnlist(kvm_t *kd, struct kvm_nlist *list)
{
kvaddr_t addr;
int error, nfail;
if (kd->resolve_symbol == NULL) {
struct nlist *nl;
int count, i;
for (count = 0; list[count].n_name != NULL &&
list[count].n_name[0] != '\0'; count++)
;
nl = calloc(count + 1, sizeof(*nl));
for (i = 0; i < count; i++)
nl[i].n_name = list[i].n_name;
nfail = __fdnlist(kd->nlfd, nl);
for (i = 0; i < count; i++) {
list[i].n_type = nl[i].n_type;
list[i].n_value = nl[i].n_value;
}
free(nl);
return (nfail);
}
nfail = 0;
while (list->n_name != NULL && list->n_name[0] != '\0') {
error = kd->resolve_symbol(list->n_name, &addr);
if (error != 0) {
nfail++;
list->n_value = 0;
list->n_type = 0;
} else {
list->n_value = addr;
list->n_type = N_DATA | N_EXT;
}
list++;
}
return (nfail);
}
char *
kvm_geterr(kvm_t *kd)
{
return (kd->errbuf);
}
#include <stdarg.h>
/*
* Report an error using printf style arguments. "program" is kd->program
* on hard errors, and 0 on soft errors, so that under sun error emulation,
* only hard errors are printed out (otherwise, programs like gdb will
* generate tons of error messages when trying to access bogus pointers).
*/
void
_kvm_err(kvm_t *kd, const char *program, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
if (program != NULL) {
(void)fprintf(stderr, "%s: ", program);
(void)vfprintf(stderr, fmt, ap);
(void)fputc('\n', stderr);
} else
(void)vsnprintf(kd->errbuf,
sizeof(kd->errbuf), fmt, ap);
va_end(ap);
}
void
_kvm_syserr(kvm_t *kd, const char *program, const char *fmt, ...)
{
va_list ap;
int n;
va_start(ap, fmt);
if (program != NULL) {
(void)fprintf(stderr, "%s: ", program);
(void)vfprintf(stderr, fmt, ap);
(void)fprintf(stderr, ": %s\n", strerror(errno));
} else {
char *cp = kd->errbuf;
(void)vsnprintf(cp, sizeof(kd->errbuf), fmt, ap);
n = strlen(cp);
(void)snprintf(&cp[n], sizeof(kd->errbuf) - n, ": %s",
strerror(errno));
}
va_end(ap);
}
void *
_kvm_malloc(kvm_t *kd, size_t n)
{
void *p;
if ((p = calloc(n, sizeof(char))) == NULL)
_kvm_err(kd, kd->program, "can't allocate %zu bytes: %s",
n, strerror(errno));
return (p);
}
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);
}
}
int
_kvm_probe_elf_kernel(kvm_t *kd, int class, int machine)
{
return (kd->nlehdr.e_ident[EI_CLASS] == class &&
kd->nlehdr.e_type == ET_EXEC &&
kd->nlehdr.e_machine == machine);
}
int
_kvm_is_minidump(kvm_t *kd)
{
char minihdr[8];
if (kd->rawdump)
return (0);
if (pread(kd->pmfd, &minihdr, 8, 0) == 8 &&
memcmp(&minihdr, "minidump", 8) == 0)
return (1);
return (0);
}
/*
* The powerpc backend has a hack to strip a leading kerneldump
* header from the core before treating it as an ELF header.
*
* We can add that here if we can get a change to libelf to support
* an initial offset into the file. Alternatively we could patch
* savecore to extract cores from a regular file instead.
*/
int
_kvm_read_core_phdrs(kvm_t *kd, size_t *phnump, GElf_Phdr **phdrp)
{
GElf_Ehdr ehdr;
GElf_Phdr *phdr;
Elf *elf;
size_t i, phnum;
elf = elf_begin(kd->pmfd, 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, "invalid core");
goto bad;
}
if (gelf_getclass(elf) != kd->nlehdr.e_ident[EI_CLASS]) {
_kvm_err(kd, kd->program, "invalid core");
goto bad;
}
if (gelf_getehdr(elf, &ehdr) == NULL) {
_kvm_err(kd, kd->program, "%s", elf_errmsg(0));
goto bad;
}
if (ehdr.e_type != ET_CORE) {
_kvm_err(kd, kd->program, "invalid core");
goto bad;
}
if (ehdr.e_machine != kd->nlehdr.e_machine) {
_kvm_err(kd, kd->program, "invalid core");
goto bad;
}
if (elf_getphdrnum(elf, &phnum) == -1) {
_kvm_err(kd, kd->program, "%s", elf_errmsg(0));
goto bad;
}
phdr = calloc(phnum, sizeof(*phdr));
if (phdr == NULL) {
_kvm_err(kd, kd->program, "failed to allocate phdrs");
goto bad;
}
for (i = 0; i < phnum; i++) {
if (gelf_getphdr(elf, i, &phdr[i]) == NULL) {
_kvm_err(kd, kd->program, "%s", elf_errmsg(0));
goto bad;
}
}
elf_end(elf);
*phnump = phnum;
*phdrp = phdr;
return (0);
bad:
elf_end(elf);
return (-1);
}
static void
_kvm_hpt_insert(struct hpt *hpt, uint64_t pa, off_t off)
{
struct hpte *hpte;
uint32_t fnv = FNV1_32_INIT;
fnv = fnv_32_buf(&pa, sizeof(pa), fnv);
fnv &= (HPT_SIZE - 1);
hpte = malloc(sizeof(*hpte));
hpte->pa = pa;
hpte->off = off;
hpte->next = hpt->hpt_head[fnv];
hpt->hpt_head[fnv] = hpte;
}
void
_kvm_hpt_init(kvm_t *kd, struct hpt *hpt, void *base, size_t len, off_t off,
int page_size, int word_size)
{
uint64_t bits, idx, pa;
uint64_t *base64;
uint32_t *base32;
base64 = base;
base32 = base;
for (idx = 0; idx < len / word_size; idx++) {
if (word_size == sizeof(uint64_t))
bits = _kvm64toh(kd, base64[idx]);
else
bits = _kvm32toh(kd, base32[idx]);
pa = idx * word_size * NBBY * page_size;
for (; bits != 0; bits >>= 1, pa += page_size) {
if ((bits & 1) == 0)
continue;
_kvm_hpt_insert(hpt, pa, off);
off += page_size;
}
}
}
off_t
_kvm_hpt_find(struct hpt *hpt, uint64_t pa)
{
struct hpte *hpte;
uint32_t fnv = FNV1_32_INIT;
fnv = fnv_32_buf(&pa, sizeof(pa), fnv);
fnv &= (HPT_SIZE - 1);
for (hpte = hpt->hpt_head[fnv]; hpte != NULL; hpte = hpte->next) {
if (pa == hpte->pa)
return (hpte->off);
}
return (-1);
}
void
_kvm_hpt_free(struct hpt *hpt)
{
struct hpte *hpte, *next;
int i;
for (i = 0; i < HPT_SIZE; i++) {
for (hpte = hpt->hpt_head[i]; hpte != NULL; hpte = next) {
next = hpte->next;
free(hpte);
}
}
}
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 a crash dump.
* 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)
kd->rawdump = 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 (0);
}
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 (0);
}
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 (0);
}
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 (0);
}
kd->resolve_symbol = resolver;
return (_kvm_open(kd, uf, mf, flag, errout));
}
int
kvm_close(kvm_t *kd)
{
int error = 0;
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);
free((void *)kd);
return (0);
}
/*
* Walk the list of unresolved symbols, generate a new list and prefix the
* symbol names, try again, and merge back what we could resolve.
*/
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))
{
struct kvm_nlist *n, *np, *p;
char *cp, *ce;
const char *ccp;
size_t len;
int slen, unresolved;
/*
* Calculate the space we need to malloc for nlist and names.
* We are going to store the name twice for later lookups: once
* with the prefix and once the unmodified name delmited by \0.
*/
len = 0;
unresolved = 0;
for (p = nl; p->n_name && p->n_name[0]; ++p) {
if (p->n_type != N_UNDF)
continue;
len += sizeof(struct kvm_nlist) + strlen(prefix) +
2 * (strlen(p->n_name) + 1);
unresolved++;
}
if (unresolved == 0)
return (unresolved);
/* Add space for the terminating nlist entry. */
len += sizeof(struct kvm_nlist);
unresolved++;
/* Alloc one chunk for (nlist, [names]) and setup pointers. */
n = np = malloc(len);
bzero(n, len);
if (n == NULL)
return (missing);
cp = ce = (char *)np;
cp += unresolved * sizeof(struct kvm_nlist);
ce += len;
/* Generate shortened nlist with special prefix. */
unresolved = 0;
for (p = nl; p->n_name && p->n_name[0]; ++p) {
if (p->n_type != N_UNDF)
continue;
*np = *p;
/* Save the new\0orig. name so we can later match it again. */
slen = snprintf(cp, ce - cp, "%s%s%c%s", prefix,
(prefix[0] != '\0' && p->n_name[0] == '_') ?
(p->n_name + 1) : p->n_name, '\0', p->n_name);
if (slen < 0 || slen >= ce - cp)
continue;
np->n_name = cp;
cp += slen + 1;
np++;
unresolved++;
}
/* Do lookup on the reduced list. */
np = n;
unresolved = kvm_fdnlist(kd, np);
/* Check if we could resolve further symbols and update the list. */
if (unresolved >= 0 && unresolved < missing) {
/* Find the first freshly resolved entry. */
for (; np->n_name && np->n_name[0]; np++)
if (np->n_type != N_UNDF)
break;
/*
* The lists are both in the same order,
* so we can walk them in parallel.
*/
for (p = nl; np->n_name && np->n_name[0] &&
p->n_name && p->n_name[0]; ++p) {
if (p->n_type != N_UNDF)
continue;
/* Skip expanded name and compare to orig. one. */
ccp = np->n_name + strlen(np->n_name) + 1;
if (strcmp(ccp, p->n_name) != 0)
continue;
/* Update nlist with new, translated results. */
p->n_type = np->n_type;
if (validate_fn)
p->n_value = (*validate_fn)(kd, np->n_value);
else
p->n_value = np->n_value;
missing--;
/* Find next freshly resolved entry. */
for (np++; np->n_name && np->n_name[0]; np++)
if (np->n_type != N_UNDF)
break;
}
}
/* We could assert missing = unresolved here. */
free(n);
return (unresolved);
}
int
_kvm_nlist(kvm_t *kd, struct kvm_nlist *nl, int initialize)
{
struct kvm_nlist *p;
int nvalid;
struct kld_sym_lookup lookup;
int error;
const char *prefix = "";
char symname[1024]; /* XXX-BZ symbol name length limit? */
int tried_vnet, tried_dpcpu;
/*
* If we can't use the kld symbol lookup, revert to the
* slow library call.
*/
if (!ISALIVE(kd)) {
error = kvm_fdnlist(kd, nl);
if (error <= 0) /* Hard error or success. */
return (error);
if (_kvm_vnet_initialized(kd, initialize))
error = kvm_fdnlist_prefix(kd, nl, error,
VNET_SYMPREFIX, _kvm_vnet_validaddr);
if (error > 0 && _kvm_dpcpu_initialized(kd, initialize))
error = kvm_fdnlist_prefix(kd, nl, error,
DPCPU_SYMPREFIX, _kvm_dpcpu_validaddr);
return (error);
}
/*
* We can use the kld lookup syscall. Go through each nlist entry
* and look it up with a kldsym(2) syscall.
*/
nvalid = 0;
tried_vnet = 0;
tried_dpcpu = 0;
again:
for (p = nl; p->n_name && p->n_name[0]; ++p) {
if (p->n_type != N_UNDF)
continue;
lookup.version = sizeof(lookup);
lookup.symvalue = 0;
lookup.symsize = 0;
error = snprintf(symname, sizeof(symname), "%s%s", prefix,
(prefix[0] != '\0' && p->n_name[0] == '_') ?
(p->n_name + 1) : p->n_name);
if (error < 0 || error >= (int)sizeof(symname))
continue;
lookup.symname = symname;
if (lookup.symname[0] == '_')
lookup.symname++;
if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) {
p->n_type = N_TEXT;
if (_kvm_vnet_initialized(kd, initialize) &&
strcmp(prefix, VNET_SYMPREFIX) == 0)
p->n_value =
_kvm_vnet_validaddr(kd, lookup.symvalue);
else if (_kvm_dpcpu_initialized(kd, initialize) &&
strcmp(prefix, DPCPU_SYMPREFIX) == 0)
p->n_value =
_kvm_dpcpu_validaddr(kd, lookup.symvalue);
else
p->n_value = lookup.symvalue;
++nvalid;
/* lookup.symsize */
}
}
/*
* Check the number of entries that weren't found. If they exist,
* try again with a prefix for virtualized or DPCPU symbol names.
*/
error = ((p - nl) - nvalid);
if (error && _kvm_vnet_initialized(kd, initialize) && !tried_vnet) {
tried_vnet = 1;
prefix = VNET_SYMPREFIX;
goto again;
}
if (error && _kvm_dpcpu_initialized(kd, initialize) && !tried_dpcpu) {
tried_dpcpu = 1;
prefix = DPCPU_SYMPREFIX;
goto again;
}
/*
* Return the number of entries that weren't found. If they exist,
* also fill internal error buffer.
*/
error = ((p - nl) - nvalid);
if (error)
_kvm_syserr(kd, kd->program, "kvm_nlist");
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));
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;
}
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;
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);
} else {
_kvm_err(kd, kd->program,
"kvm_write not implemented for dead kernels");
return (-1);
}
/* NOTREACHED */
}
int
kvm_native(kvm_t *kd)
{
if (ISALIVE(kd))
return (1);
return (kd->arch->ka_native(kd));
}