2 * Copyright (c) 2008 Robert N. M. Watson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/types.h>
31 #include <sys/sysctl.h>
47 * Interface with the ddb(4) capture buffer of a live kernel using sysctl, or
48 * for a crash dump using libkvm.
50 #define SYSCTL_DDB_CAPTURE_BUFOFF "debug.ddb.capture.bufoff"
51 #define SYSCTL_DDB_CAPTURE_BUFSIZE "debug.ddb.capture.bufsize"
52 #define SYSCTL_DDB_CAPTURE_MAXBUFSIZE "debug.ddb.capture.maxbufsize"
53 #define SYSCTL_DDB_CAPTURE_DATA "debug.ddb.capture.data"
54 #define SYSCTL_DDB_CAPTURE_INPROGRESS "debug.ddb.capture.inprogress"
56 static struct nlist namelist[] = {
57 #define X_DB_CAPTURE_BUF 0
58 { .n_name = "_db_capture_buf" },
59 #define X_DB_CAPTURE_BUFSIZE 1
60 { .n_name = "_db_capture_bufsize" },
61 #define X_DB_CAPTURE_MAXBUFSIZE 2
62 { .n_name = "_db_capture_maxbufsize" },
63 #define X_DB_CAPTURE_BUFOFF 3
64 { .n_name = "_db_capture_bufoff" },
65 #define X_DB_CAPTURE_INPROGRESS 4
66 { .n_name = "_db_capture_inprogress" },
71 kread(kvm_t *kvm, void *kvm_pointer, void *address, size_t size,
76 ret = kvm_read(kvm, (unsigned long)kvm_pointer + offset, address,
78 if (ret < 0 || (size_t)ret != size)
84 kread_symbol(kvm_t *kvm, int index, void *address, size_t size,
89 ret = kvm_read(kvm, namelist[index].n_value + offset, address, size);
90 if (ret < 0 || (size_t)ret != size)
96 ddb_capture_print_kvm(kvm_t *kvm)
98 u_int db_capture_bufoff;
99 char *buffer, *db_capture_buf;
101 if (kread_symbol(kvm, X_DB_CAPTURE_BUF, &db_capture_buf,
102 sizeof(db_capture_buf), 0) < 0)
103 errx(-1, "kvm: unable to read db_capture_buf");
105 if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff,
106 sizeof(db_capture_bufoff), 0) < 0)
107 errx(-1, "kvm: unable to read db_capture_bufoff");
109 buffer = malloc(db_capture_bufoff + 1);
111 err(-1, "malloc: db_capture_bufoff (%u)",
113 bzero(buffer, db_capture_bufoff + 1);
115 if (kread(kvm, db_capture_buf, buffer, db_capture_bufoff, 0) < 0)
116 errx(-1, "kvm: unable to read buffer");
118 printf("%s\n", buffer);
123 ddb_capture_print_sysctl(void)
130 if (sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, NULL, &buflen, NULL, 0) < 0)
131 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
134 buffer = malloc(buflen);
136 err(EX_OSERR, "malloc");
137 bzero(buffer, buflen);
139 ret = sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, buffer, &len, NULL, 0);
140 if (ret < 0 && errno != ENOMEM)
141 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
147 printf("%s\n", buffer);
152 ddb_capture_status_kvm(kvm_t *kvm)
154 u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
156 if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff,
157 sizeof(db_capture_bufoff), 0) < 0)
158 errx(-1, "kvm: unable to read db_capture_bufoff");
159 if (kread_symbol(kvm, X_DB_CAPTURE_BUFSIZE, &db_capture_bufsize,
160 sizeof(db_capture_bufsize), 0) < 0)
161 errx(-1, "kvm: unable to read db_capture_bufsize");
162 if (kread_symbol(kvm, X_DB_CAPTURE_INPROGRESS,
163 &db_capture_inprogress, sizeof(db_capture_inprogress), 0) < 0)
164 err(-1, "kvm: unable to read db_capture_inprogress");
165 printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize);
166 if (db_capture_inprogress)
167 printf("capture is on\n");
169 printf("capture is off\n");
174 ddb_capture_status_sysctl(void)
176 u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
179 len = sizeof(db_capture_bufoff);
180 if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFOFF, &db_capture_bufoff, &len,
182 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFOFF);
183 len = sizeof(db_capture_bufoff);
184 if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFSIZE, &db_capture_bufsize,
186 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFSIZE);
187 len = sizeof(db_capture_inprogress);
188 if (sysctlbyname(SYSCTL_DDB_CAPTURE_INPROGRESS,
189 &db_capture_inprogress, &len, NULL, 0) < 0)
190 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_INPROGRESS);
191 printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize);
192 if (db_capture_inprogress)
193 printf("capture is on\n");
195 printf("capture is off\n");
199 ddb_capture(int argc, char *argv[])
201 char *mflag, *nflag, errbuf[_POSIX2_LINE_MAX];
208 while ((ch = getopt(argc, argv, "M:N:")) != -1) {
229 kvm = kvm_openfiles(nflag, mflag, NULL, O_RDONLY, errbuf);
231 errx(-1, "ddb_capture: kvm_openfiles: %s", errbuf);
232 if (kvm_nlist(kvm, namelist) != 0)
233 errx(-1, "ddb_capture: kvm_nlist");
234 } else if (nflag != NULL)
236 if (strcmp(argv[0], "print") == 0) {
238 ddb_capture_print_kvm(kvm);
240 ddb_capture_print_sysctl();
241 } else if (strcmp(argv[0], "status") == 0) {
243 ddb_capture_status_kvm(kvm);
245 ddb_capture_status_sysctl();