5ef5fd6e53
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
249 lines
6.8 KiB
C
249 lines
6.8 KiB
C
/*-
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* Copyright (c) 2008 Robert N. M. Watson
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* All rights reserved.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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#include <sys/types.h>
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#include <sys/sysctl.h>
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#include <err.h>
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#include <errno.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 <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sysexits.h>
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#include <unistd.h>
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#include "ddb.h"
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/*
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* Interface with the ddb(4) capture buffer of a live kernel using sysctl, or
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* for a crash dump using libkvm.
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*/
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#define SYSCTL_DDB_CAPTURE_BUFOFF "debug.ddb.capture.bufoff"
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#define SYSCTL_DDB_CAPTURE_BUFSIZE "debug.ddb.capture.bufsize"
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#define SYSCTL_DDB_CAPTURE_MAXBUFSIZE "debug.ddb.capture.maxbufsize"
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#define SYSCTL_DDB_CAPTURE_DATA "debug.ddb.capture.data"
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#define SYSCTL_DDB_CAPTURE_INPROGRESS "debug.ddb.capture.inprogress"
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static struct nlist namelist[] = {
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#define X_DB_CAPTURE_BUF 0
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{ .n_name = "_db_capture_buf" },
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#define X_DB_CAPTURE_BUFSIZE 1
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{ .n_name = "_db_capture_bufsize" },
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#define X_DB_CAPTURE_MAXBUFSIZE 2
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{ .n_name = "_db_capture_maxbufsize" },
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#define X_DB_CAPTURE_BUFOFF 3
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{ .n_name = "_db_capture_bufoff" },
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#define X_DB_CAPTURE_INPROGRESS 4
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{ .n_name = "_db_capture_inprogress" },
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{ .n_name = "" },
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};
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static int
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kread(kvm_t *kvm, void *kvm_pointer, void *address, size_t size,
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size_t offset)
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{
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ssize_t ret;
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ret = kvm_read(kvm, (unsigned long)kvm_pointer + offset, address,
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size);
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if (ret < 0 || (size_t)ret != size)
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return (-1);
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return (0);
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}
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static int
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kread_symbol(kvm_t *kvm, int index, void *address, size_t size,
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size_t offset)
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{
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ssize_t ret;
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ret = kvm_read(kvm, namelist[index].n_value + offset, address, size);
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if (ret < 0 || (size_t)ret != size)
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return (-1);
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return (0);
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}
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static void
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ddb_capture_print_kvm(kvm_t *kvm)
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{
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u_int db_capture_bufoff;
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char *buffer, *db_capture_buf;
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if (kread_symbol(kvm, X_DB_CAPTURE_BUF, &db_capture_buf,
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sizeof(db_capture_buf), 0) < 0)
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errx(-1, "kvm: unable to read db_capture_buf");
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if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff,
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sizeof(db_capture_bufoff), 0) < 0)
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errx(-1, "kvm: unable to read db_capture_bufoff");
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buffer = malloc(db_capture_bufoff + 1);
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if (buffer == NULL)
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err(-1, "malloc: db_capture_bufoff (%u)",
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db_capture_bufoff);
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bzero(buffer, db_capture_bufoff + 1);
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if (kread(kvm, db_capture_buf, buffer, db_capture_bufoff, 0) < 0)
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errx(-1, "kvm: unable to read buffer");
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printf("%s\n", buffer);
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free(buffer);
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}
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static void
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ddb_capture_print_sysctl(void)
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{
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size_t buflen, len;
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char *buffer;
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int ret;
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repeat:
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if (sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, NULL, &buflen, NULL, 0) < 0)
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err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
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if (buflen == 0)
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return;
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buffer = malloc(buflen);
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if (buffer == NULL)
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err(EX_OSERR, "malloc");
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bzero(buffer, buflen);
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len = buflen;
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ret = sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, buffer, &len, NULL, 0);
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if (ret < 0 && errno != ENOMEM)
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err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
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if (ret < 0) {
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free(buffer);
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goto repeat;
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}
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printf("%s\n", buffer);
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free(buffer);
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}
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static void
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ddb_capture_status_kvm(kvm_t *kvm)
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{
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u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
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if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff,
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sizeof(db_capture_bufoff), 0) < 0)
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errx(-1, "kvm: unable to read db_capture_bufoff");
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if (kread_symbol(kvm, X_DB_CAPTURE_BUFSIZE, &db_capture_bufsize,
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sizeof(db_capture_bufsize), 0) < 0)
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errx(-1, "kvm: unable to read db_capture_bufsize");
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if (kread_symbol(kvm, X_DB_CAPTURE_INPROGRESS,
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&db_capture_inprogress, sizeof(db_capture_inprogress), 0) < 0)
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err(-1, "kvm: unable to read db_capture_inprogress");
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printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize);
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if (db_capture_inprogress)
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printf("capture is on\n");
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else
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printf("capture is off\n");
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}
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static void
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ddb_capture_status_sysctl(void)
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{
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u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
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size_t len;
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len = sizeof(db_capture_bufoff);
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if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFOFF, &db_capture_bufoff, &len,
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NULL, 0) < 0)
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err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFOFF);
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len = sizeof(db_capture_bufoff);
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if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFSIZE, &db_capture_bufsize,
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&len, NULL, 0) < 0)
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err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFSIZE);
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len = sizeof(db_capture_inprogress);
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if (sysctlbyname(SYSCTL_DDB_CAPTURE_INPROGRESS,
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&db_capture_inprogress, &len, NULL, 0) < 0)
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err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_INPROGRESS);
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printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize);
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if (db_capture_inprogress)
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printf("capture is on\n");
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else
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printf("capture is off\n");
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}
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void
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ddb_capture(int argc, char *argv[])
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{
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char *mflag, *nflag, errbuf[_POSIX2_LINE_MAX];
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kvm_t *kvm;
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int ch;
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mflag = NULL;
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nflag = NULL;
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kvm = NULL;
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while ((ch = getopt(argc, argv, "M:N:")) != -1) {
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switch (ch) {
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case 'M':
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mflag = optarg;
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break;
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case 'N':
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nflag = optarg;
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break;
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default:
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usage();
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}
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}
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argc -= optind;
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argv += optind;
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if (argc != 1)
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usage();
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if (mflag != NULL) {
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kvm = kvm_openfiles(nflag, mflag, NULL, O_RDONLY, errbuf);
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if (kvm == NULL)
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errx(-1, "ddb_capture: kvm_openfiles: %s", errbuf);
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if (kvm_nlist(kvm, namelist) != 0)
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errx(-1, "ddb_capture: kvm_nlist");
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} else if (nflag != NULL)
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usage();
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if (strcmp(argv[0], "print") == 0) {
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if (kvm != NULL)
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ddb_capture_print_kvm(kvm);
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else
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ddb_capture_print_sysctl();
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} else if (strcmp(argv[0], "status") == 0) {
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if (kvm != NULL)
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ddb_capture_status_kvm(kvm);
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else
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ddb_capture_status_sysctl();
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} else
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usage();
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}
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