freebsd-dev/sbin/ddb/ddb_capture.c
John Baldwin 5ef5fd6e53 Ensure 'kvm' is always initialized. If "-M" was not specified and the
garbage value on the stack was not zero, then 'ddb capture' would try to
use the garbage value as a kvm_t pointer.

MFC after:	1 week
2009-11-02 20:18:50 +00:00

249 lines
6.8 KiB
C

/*-
* Copyright (c) 2008 Robert N. M. Watson
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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("$FreeBSD$");
#include <sys/types.h>
#include <sys/sysctl.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <kvm.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>
#include "ddb.h"
/*
* Interface with the ddb(4) capture buffer of a live kernel using sysctl, or
* for a crash dump using libkvm.
*/
#define SYSCTL_DDB_CAPTURE_BUFOFF "debug.ddb.capture.bufoff"
#define SYSCTL_DDB_CAPTURE_BUFSIZE "debug.ddb.capture.bufsize"
#define SYSCTL_DDB_CAPTURE_MAXBUFSIZE "debug.ddb.capture.maxbufsize"
#define SYSCTL_DDB_CAPTURE_DATA "debug.ddb.capture.data"
#define SYSCTL_DDB_CAPTURE_INPROGRESS "debug.ddb.capture.inprogress"
static struct nlist namelist[] = {
#define X_DB_CAPTURE_BUF 0
{ .n_name = "_db_capture_buf" },
#define X_DB_CAPTURE_BUFSIZE 1
{ .n_name = "_db_capture_bufsize" },
#define X_DB_CAPTURE_MAXBUFSIZE 2
{ .n_name = "_db_capture_maxbufsize" },
#define X_DB_CAPTURE_BUFOFF 3
{ .n_name = "_db_capture_bufoff" },
#define X_DB_CAPTURE_INPROGRESS 4
{ .n_name = "_db_capture_inprogress" },
{ .n_name = "" },
};
static int
kread(kvm_t *kvm, void *kvm_pointer, void *address, size_t size,
size_t offset)
{
ssize_t ret;
ret = kvm_read(kvm, (unsigned long)kvm_pointer + offset, address,
size);
if (ret < 0 || (size_t)ret != size)
return (-1);
return (0);
}
static int
kread_symbol(kvm_t *kvm, int index, void *address, size_t size,
size_t offset)
{
ssize_t ret;
ret = kvm_read(kvm, namelist[index].n_value + offset, address, size);
if (ret < 0 || (size_t)ret != size)
return (-1);
return (0);
}
static void
ddb_capture_print_kvm(kvm_t *kvm)
{
u_int db_capture_bufoff;
char *buffer, *db_capture_buf;
if (kread_symbol(kvm, X_DB_CAPTURE_BUF, &db_capture_buf,
sizeof(db_capture_buf), 0) < 0)
errx(-1, "kvm: unable to read db_capture_buf");
if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff,
sizeof(db_capture_bufoff), 0) < 0)
errx(-1, "kvm: unable to read db_capture_bufoff");
buffer = malloc(db_capture_bufoff + 1);
if (buffer == NULL)
err(-1, "malloc: db_capture_bufoff (%u)",
db_capture_bufoff);
bzero(buffer, db_capture_bufoff + 1);
if (kread(kvm, db_capture_buf, buffer, db_capture_bufoff, 0) < 0)
errx(-1, "kvm: unable to read buffer");
printf("%s\n", buffer);
free(buffer);
}
static void
ddb_capture_print_sysctl(void)
{
size_t buflen, len;
char *buffer;
int ret;
repeat:
if (sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, NULL, &buflen, NULL, 0) < 0)
err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
if (buflen == 0)
return;
buffer = malloc(buflen);
if (buffer == NULL)
err(EX_OSERR, "malloc");
bzero(buffer, buflen);
len = buflen;
ret = sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, buffer, &len, NULL, 0);
if (ret < 0 && errno != ENOMEM)
err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
if (ret < 0) {
free(buffer);
goto repeat;
}
printf("%s\n", buffer);
free(buffer);
}
static void
ddb_capture_status_kvm(kvm_t *kvm)
{
u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff,
sizeof(db_capture_bufoff), 0) < 0)
errx(-1, "kvm: unable to read db_capture_bufoff");
if (kread_symbol(kvm, X_DB_CAPTURE_BUFSIZE, &db_capture_bufsize,
sizeof(db_capture_bufsize), 0) < 0)
errx(-1, "kvm: unable to read db_capture_bufsize");
if (kread_symbol(kvm, X_DB_CAPTURE_INPROGRESS,
&db_capture_inprogress, sizeof(db_capture_inprogress), 0) < 0)
err(-1, "kvm: unable to read db_capture_inprogress");
printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize);
if (db_capture_inprogress)
printf("capture is on\n");
else
printf("capture is off\n");
}
static void
ddb_capture_status_sysctl(void)
{
u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
size_t len;
len = sizeof(db_capture_bufoff);
if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFOFF, &db_capture_bufoff, &len,
NULL, 0) < 0)
err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFOFF);
len = sizeof(db_capture_bufoff);
if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFSIZE, &db_capture_bufsize,
&len, NULL, 0) < 0)
err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFSIZE);
len = sizeof(db_capture_inprogress);
if (sysctlbyname(SYSCTL_DDB_CAPTURE_INPROGRESS,
&db_capture_inprogress, &len, NULL, 0) < 0)
err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_INPROGRESS);
printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize);
if (db_capture_inprogress)
printf("capture is on\n");
else
printf("capture is off\n");
}
void
ddb_capture(int argc, char *argv[])
{
char *mflag, *nflag, errbuf[_POSIX2_LINE_MAX];
kvm_t *kvm;
int ch;
mflag = NULL;
nflag = NULL;
kvm = NULL;
while ((ch = getopt(argc, argv, "M:N:")) != -1) {
switch (ch) {
case 'M':
mflag = optarg;
break;
case 'N':
nflag = optarg;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (argc != 1)
usage();
if (mflag != NULL) {
kvm = kvm_openfiles(nflag, mflag, NULL, O_RDONLY, errbuf);
if (kvm == NULL)
errx(-1, "ddb_capture: kvm_openfiles: %s", errbuf);
if (kvm_nlist(kvm, namelist) != 0)
errx(-1, "ddb_capture: kvm_nlist");
} else if (nflag != NULL)
usage();
if (strcmp(argv[0], "print") == 0) {
if (kvm != NULL)
ddb_capture_print_kvm(kvm);
else
ddb_capture_print_sysctl();
} else if (strcmp(argv[0], "status") == 0) {
if (kvm != NULL)
ddb_capture_status_kvm(kvm);
else
ddb_capture_status_sysctl();
} else
usage();
}