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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/src/lib/libkvm/kvm.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: release/9.1.0/lib/libkvm/kvm.c 218196 2011-02-02 17:01:26Z uqs $");
#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>
#define _WANT_VNET
#include <sys/user.h>
#include <sys/proc.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/linker.h>
#include <sys/pcpu.h>
#include <net/vnet.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <machine/vmparam.h>
#include <ctype.h>
#include <fcntl.h>
#include <kvm.h>
#include <limits.h>
#include <nlist.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include "kvm_private.h"
/* from src/lib/libc/gen/nlist.c */
int __fdnlist(int, struct nlist *);
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 kvm_t *
_kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
{
struct stat st;
kd->vmfd = -1;
kd->pmfd = -1;
kd->nlfd = -1;
kd->vmst = 0;
kd->procbase = 0;
kd->argspc = 0;
kd->argv = 0;
if (uf == 0)
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 == 0)
mf = _PATH_MEM;
if ((kd->pmfd = open(mf, flag, 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 (fcntl(kd->pmfd, F_SETFD, FD_CLOEXEC) < 0) {
_kvm_syserr(kd, kd->program, "%s", mf);
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);
return (kd);
} else if (strcmp(mf, _PATH_MEM) == 0) {
if ((kd->vmfd = open(_PATH_KMEM, flag)) < 0) {
_kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
goto failed;
}
if (fcntl(kd->vmfd, F_SETFD, FD_CLOEXEC) < 0) {
_kvm_syserr(kd, kd->program, "%s", _PATH_KMEM);
goto failed;
}
return (kd);
}
}
/*
* This is a crash dump.
* Initialize the virtual address translation machinery,
* but first setup the namelist fd.
*/
if ((kd->nlfd = open(uf, O_RDONLY, 0)) < 0) {
_kvm_syserr(kd, kd->program, "%s", uf);
goto failed;
}
if (fcntl(kd->nlfd, F_SETFD, FD_CLOEXEC) < 0) {
_kvm_syserr(kd, kd->program, "%s", uf);
goto failed;
}
if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0)
kd->rawdump = 1;
if (_kvm_initvtop(kd) < 0)
goto failed;
return (kd);
failed:
/*
* Copy out the error if doing sane error semantics.
*/
if (errout != 0)
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) {
(void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX);
return (0);
}
kd->program = 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));
}
int
kvm_close(kvm_t *kd)
{
int error = 0;
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->vmst)
_kvm_freevtop(kd);
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 nlist *nl, int missing, const char *prefix,
uintptr_t (*validate_fn)(kvm_t *, uintptr_t))
{
struct 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 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 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 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;
bcopy(p, np, sizeof(struct nlist));
/* 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 = __fdnlist(kd->nlfd, 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;
p->n_other = np->n_other;
p->n_desc = np->n_desc;
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 nlist *nl, int initialize)
{
struct 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 = __fdnlist(kd->nlfd, 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;
p->n_other = 0;
p->n_desc = 0;
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_nlist(kvm_t *kd, struct nlist *nl)
{
/*
* If called via the public interface, permit intialization of
* further virtualized modules on demand.
*/
return (_kvm_nlist(kd, nl, 1));
}
ssize_t
kvm_read(kvm_t *kd, u_long 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 (%lx)", 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 = _kvm_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 kvm_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 */
}