2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2008 Robert N. M. Watson
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/types.h>
33 #include <sys/sysctl.h>
49 * Interface with the ddb(4) capture buffer of a live kernel using sysctl, or
50 * for a crash dump using libkvm.
52 #define SYSCTL_DDB_CAPTURE_BUFOFF "debug.ddb.capture.bufoff"
53 #define SYSCTL_DDB_CAPTURE_BUFSIZE "debug.ddb.capture.bufsize"
54 #define SYSCTL_DDB_CAPTURE_MAXBUFSIZE "debug.ddb.capture.maxbufsize"
55 #define SYSCTL_DDB_CAPTURE_DATA "debug.ddb.capture.data"
56 #define SYSCTL_DDB_CAPTURE_INPROGRESS "debug.ddb.capture.inprogress"
58 static struct nlist namelist[] = {
59 #define X_DB_CAPTURE_BUF 0
60 { .n_name = "_db_capture_buf" },
61 #define X_DB_CAPTURE_BUFSIZE 1
62 { .n_name = "_db_capture_bufsize" },
63 #define X_DB_CAPTURE_MAXBUFSIZE 2
64 { .n_name = "_db_capture_maxbufsize" },
65 #define X_DB_CAPTURE_BUFOFF 3
66 { .n_name = "_db_capture_bufoff" },
67 #define X_DB_CAPTURE_INPROGRESS 4
68 { .n_name = "_db_capture_inprogress" },
73 kread(kvm_t *kvm, void *kvm_pointer, void *address, size_t size,
78 ret = kvm_read(kvm, (unsigned long)kvm_pointer + offset, address,
80 if (ret < 0 || (size_t)ret != size)
86 kread_symbol(kvm_t *kvm, int read_index, void *address, size_t size,
91 ret = kvm_read(kvm, namelist[read_index].n_value + offset, address, size);
92 if (ret < 0 || (size_t)ret != size)
98 ddb_capture_print_kvm(kvm_t *kvm)
100 u_int db_capture_bufoff;
101 char *buffer, *db_capture_buf;
103 if (kread_symbol(kvm, X_DB_CAPTURE_BUF, &db_capture_buf,
104 sizeof(db_capture_buf), 0) < 0)
105 errx(-1, "kvm: unable to read db_capture_buf");
107 if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff,
108 sizeof(db_capture_bufoff), 0) < 0)
109 errx(-1, "kvm: unable to read db_capture_bufoff");
111 buffer = malloc(db_capture_bufoff + 1);
113 err(-1, "malloc: db_capture_bufoff (%u)",
115 bzero(buffer, db_capture_bufoff + 1);
117 if (kread(kvm, db_capture_buf, buffer, db_capture_bufoff, 0) < 0)
118 errx(-1, "kvm: unable to read buffer");
120 printf("%s\n", buffer);
125 ddb_capture_print_sysctl(void)
132 if (sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, NULL, &buflen, NULL, 0) < 0)
133 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
136 buffer = malloc(buflen);
138 err(EX_OSERR, "malloc");
139 bzero(buffer, buflen);
141 ret = sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, buffer, &len, NULL, 0);
142 if (ret < 0 && errno != ENOMEM)
143 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
149 printf("%s\n", buffer);
154 ddb_capture_status_kvm(kvm_t *kvm)
156 u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
158 if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff,
159 sizeof(db_capture_bufoff), 0) < 0)
160 errx(-1, "kvm: unable to read db_capture_bufoff");
161 if (kread_symbol(kvm, X_DB_CAPTURE_BUFSIZE, &db_capture_bufsize,
162 sizeof(db_capture_bufsize), 0) < 0)
163 errx(-1, "kvm: unable to read db_capture_bufsize");
164 if (kread_symbol(kvm, X_DB_CAPTURE_INPROGRESS,
165 &db_capture_inprogress, sizeof(db_capture_inprogress), 0) < 0)
166 err(-1, "kvm: unable to read db_capture_inprogress");
167 printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize);
168 if (db_capture_inprogress)
169 printf("capture is on\n");
171 printf("capture is off\n");
176 ddb_capture_status_sysctl(void)
178 u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
181 len = sizeof(db_capture_bufoff);
182 if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFOFF, &db_capture_bufoff, &len,
184 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFOFF);
185 len = sizeof(db_capture_bufoff);
186 if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFSIZE, &db_capture_bufsize,
188 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFSIZE);
189 len = sizeof(db_capture_inprogress);
190 if (sysctlbyname(SYSCTL_DDB_CAPTURE_INPROGRESS,
191 &db_capture_inprogress, &len, NULL, 0) < 0)
192 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_INPROGRESS);
193 printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize);
194 if (db_capture_inprogress)
195 printf("capture is on\n");
197 printf("capture is off\n");
201 ddb_capture(int argc, char *argv[])
203 char *mflag, *nflag, errbuf[_POSIX2_LINE_MAX];
210 while ((ch = getopt(argc, argv, "M:N:")) != -1) {
231 kvm = kvm_openfiles(nflag, mflag, NULL, O_RDONLY, errbuf);
233 errx(-1, "ddb_capture: kvm_openfiles: %s", errbuf);
234 if (kvm_nlist(kvm, namelist) != 0)
235 errx(-1, "ddb_capture: kvm_nlist");
236 } else if (nflag != NULL)
238 if (strcmp(argv[0], "print") == 0) {
240 ddb_capture_print_kvm(kvm);
242 ddb_capture_print_sysctl();
243 } else if (strcmp(argv[0], "status") == 0) {
245 ddb_capture_status_kvm(kvm);
247 ddb_capture_status_sysctl();