1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2008 Robert N. M. Watson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
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.
15 *
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
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/types.h>
30 #include <sys/sysctl.h>
31
32 #include <err.h>
33 #include <errno.h>
34 #include <fcntl.h>
35 #include <kvm.h>
36 #include <limits.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <sysexits.h>
41 #include <unistd.h>
42
43 #include "ddb.h"
44
45 /*
46 * Interface with the ddb(4) capture buffer of a live kernel using sysctl, or
47 * for a crash dump using libkvm.
48 */
49 #define SYSCTL_DDB_CAPTURE_BUFOFF "debug.ddb.capture.bufoff"
50 #define SYSCTL_DDB_CAPTURE_BUFSIZE "debug.ddb.capture.bufsize"
51 #define SYSCTL_DDB_CAPTURE_MAXBUFSIZE "debug.ddb.capture.maxbufsize"
52 #define SYSCTL_DDB_CAPTURE_DATA "debug.ddb.capture.data"
53 #define SYSCTL_DDB_CAPTURE_INPROGRESS "debug.ddb.capture.inprogress"
54
55 static struct nlist namelist[] = {
56 #define X_DB_CAPTURE_BUF 0
57 { .n_name = "_db_capture_buf" },
58 #define X_DB_CAPTURE_BUFSIZE 1
59 { .n_name = "_db_capture_bufsize" },
60 #define X_DB_CAPTURE_MAXBUFSIZE 2
61 { .n_name = "_db_capture_maxbufsize" },
62 #define X_DB_CAPTURE_BUFOFF 3
63 { .n_name = "_db_capture_bufoff" },
64 #define X_DB_CAPTURE_INPROGRESS 4
65 { .n_name = "_db_capture_inprogress" },
66 { .n_name = "" },
67 };
68
69 static int
kread(kvm_t * kvm,void * kvm_pointer,void * address,size_t size,size_t offset)70 kread(kvm_t *kvm, void *kvm_pointer, void *address, size_t size,
71 size_t offset)
72 {
73 ssize_t ret;
74
75 ret = kvm_read(kvm, (unsigned long)kvm_pointer + offset, address,
76 size);
77 if (ret < 0 || (size_t)ret != size)
78 return (-1);
79 return (0);
80 }
81
82 static int
kread_symbol(kvm_t * kvm,int read_index,void * address,size_t size,size_t offset)83 kread_symbol(kvm_t *kvm, int read_index, void *address, size_t size,
84 size_t offset)
85 {
86 ssize_t ret;
87
88 ret = kvm_read(kvm, namelist[read_index].n_value + offset, address, size);
89 if (ret < 0 || (size_t)ret != size)
90 return (-1);
91 return (0);
92 }
93
94 static void
ddb_capture_print_kvm(kvm_t * kvm)95 ddb_capture_print_kvm(kvm_t *kvm)
96 {
97 u_int db_capture_bufoff;
98 char *buffer, *db_capture_buf;
99
100 if (kread_symbol(kvm, X_DB_CAPTURE_BUF, &db_capture_buf,
101 sizeof(db_capture_buf), 0) < 0)
102 errx(-1, "kvm: unable to read db_capture_buf");
103
104 if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff,
105 sizeof(db_capture_bufoff), 0) < 0)
106 errx(-1, "kvm: unable to read db_capture_bufoff");
107
108 buffer = malloc(db_capture_bufoff + 1);
109 if (buffer == NULL)
110 err(-1, "malloc: db_capture_bufoff (%u)",
111 db_capture_bufoff);
112 bzero(buffer, db_capture_bufoff + 1);
113
114 if (kread(kvm, db_capture_buf, buffer, db_capture_bufoff, 0) < 0)
115 errx(-1, "kvm: unable to read buffer");
116
117 printf("%s\n", buffer);
118 free(buffer);
119 }
120
121 static void
ddb_capture_print_sysctl(void)122 ddb_capture_print_sysctl(void)
123 {
124 size_t buflen, len;
125 char *buffer;
126 int ret;
127
128 repeat:
129 if (sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, NULL, &buflen, NULL, 0) < 0)
130 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
131 if (buflen == 0)
132 return;
133 buffer = malloc(buflen);
134 if (buffer == NULL)
135 err(EX_OSERR, "malloc");
136 bzero(buffer, buflen);
137 len = buflen;
138 ret = sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, buffer, &len, NULL, 0);
139 if (ret < 0 && errno != ENOMEM)
140 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
141 if (ret < 0) {
142 free(buffer);
143 goto repeat;
144 }
145
146 printf("%s\n", buffer);
147 free(buffer);
148 }
149
150 static void
ddb_capture_status_kvm(kvm_t * kvm)151 ddb_capture_status_kvm(kvm_t *kvm)
152 {
153 u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
154
155 if (kread_symbol(kvm, X_DB_CAPTURE_BUFOFF, &db_capture_bufoff,
156 sizeof(db_capture_bufoff), 0) < 0)
157 errx(-1, "kvm: unable to read db_capture_bufoff");
158 if (kread_symbol(kvm, X_DB_CAPTURE_BUFSIZE, &db_capture_bufsize,
159 sizeof(db_capture_bufsize), 0) < 0)
160 errx(-1, "kvm: unable to read db_capture_bufsize");
161 if (kread_symbol(kvm, X_DB_CAPTURE_INPROGRESS,
162 &db_capture_inprogress, sizeof(db_capture_inprogress), 0) < 0)
163 err(-1, "kvm: unable to read db_capture_inprogress");
164 printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize);
165 if (db_capture_inprogress)
166 printf("capture is on\n");
167 else
168 printf("capture is off\n");
169
170 }
171
172 static void
ddb_capture_status_sysctl(void)173 ddb_capture_status_sysctl(void)
174 {
175 u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
176 size_t len;
177
178 len = sizeof(db_capture_bufoff);
179 if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFOFF, &db_capture_bufoff, &len,
180 NULL, 0) < 0)
181 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFOFF);
182 len = sizeof(db_capture_bufoff);
183 if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFSIZE, &db_capture_bufsize,
184 &len, NULL, 0) < 0)
185 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_BUFSIZE);
186 len = sizeof(db_capture_inprogress);
187 if (sysctlbyname(SYSCTL_DDB_CAPTURE_INPROGRESS,
188 &db_capture_inprogress, &len, NULL, 0) < 0)
189 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_INPROGRESS);
190 printf("%u/%u bytes used\n", db_capture_bufoff, db_capture_bufsize);
191 if (db_capture_inprogress)
192 printf("capture is on\n");
193 else
194 printf("capture is off\n");
195 }
196
197 void
ddb_capture(int argc,char * argv[])198 ddb_capture(int argc, char *argv[])
199 {
200 char *mflag, *nflag, errbuf[_POSIX2_LINE_MAX];
201 kvm_t *kvm;
202 int ch;
203
204 mflag = NULL;
205 nflag = NULL;
206 kvm = NULL;
207 while ((ch = getopt(argc, argv, "M:N:")) != -1) {
208 switch (ch) {
209 case 'M':
210 mflag = optarg;
211 break;
212
213 case 'N':
214 nflag = optarg;
215 break;
216
217 default:
218 usage();
219 }
220 }
221 argc -= optind;
222 argv += optind;
223
224 if (argc != 1)
225 usage();
226
227 if (mflag != NULL) {
228 kvm = kvm_openfiles(nflag, mflag, NULL, O_RDONLY, errbuf);
229 if (kvm == NULL)
230 errx(-1, "ddb_capture: kvm_openfiles: %s", errbuf);
231 if (kvm_nlist(kvm, namelist) != 0)
232 errx(-1, "ddb_capture: kvm_nlist");
233 } else if (nflag != NULL)
234 usage();
235 if (strcmp(argv[0], "print") == 0) {
236 if (kvm != NULL)
237 ddb_capture_print_kvm(kvm);
238 else
239 ddb_capture_print_sysctl();
240 } else if (strcmp(argv[0], "status") == 0) {
241 if (kvm != NULL)
242 ddb_capture_status_kvm(kvm);
243 else
244 ddb_capture_status_sysctl();
245 } else
246 usage();
247 }
248