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/cdefs.h>
30 #include <sys/types.h>
31 #include <sys/sysctl.h>
32
33 #include <err.h>
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <kvm.h>
37 #include <limits.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <sysexits.h>
42 #include <unistd.h>
43
44 #include "ddb.h"
45
46 /*
47 * Interface with the ddb(4) capture buffer of a live kernel using sysctl, or
48 * for a crash dump using libkvm.
49 */
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"
55
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" },
67 { .n_name = "" },
68 };
69
70 static int
kread(kvm_t * kvm,void * kvm_pointer,void * address,size_t size,size_t offset)71 kread(kvm_t *kvm, void *kvm_pointer, void *address, size_t size,
72 size_t offset)
73 {
74 ssize_t ret;
75
76 ret = kvm_read(kvm, (unsigned long)kvm_pointer + offset, address,
77 size);
78 if (ret < 0 || (size_t)ret != size)
79 return (-1);
80 return (0);
81 }
82
83 static int
kread_symbol(kvm_t * kvm,int read_index,void * address,size_t size,size_t offset)84 kread_symbol(kvm_t *kvm, int read_index, void *address, size_t size,
85 size_t offset)
86 {
87 ssize_t ret;
88
89 ret = kvm_read(kvm, namelist[read_index].n_value + offset, address, size);
90 if (ret < 0 || (size_t)ret != size)
91 return (-1);
92 return (0);
93 }
94
95 static void
ddb_capture_print_kvm(kvm_t * kvm)96 ddb_capture_print_kvm(kvm_t *kvm)
97 {
98 u_int db_capture_bufoff;
99 char *buffer, *db_capture_buf;
100
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");
104
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");
108
109 buffer = malloc(db_capture_bufoff + 1);
110 if (buffer == NULL)
111 err(-1, "malloc: db_capture_bufoff (%u)",
112 db_capture_bufoff);
113 bzero(buffer, db_capture_bufoff + 1);
114
115 if (kread(kvm, db_capture_buf, buffer, db_capture_bufoff, 0) < 0)
116 errx(-1, "kvm: unable to read buffer");
117
118 printf("%s\n", buffer);
119 free(buffer);
120 }
121
122 static void
ddb_capture_print_sysctl(void)123 ddb_capture_print_sysctl(void)
124 {
125 size_t buflen, len;
126 char *buffer;
127 int ret;
128
129 repeat:
130 if (sysctlbyname(SYSCTL_DDB_CAPTURE_DATA, NULL, &buflen, NULL, 0) < 0)
131 err(EX_OSERR, "sysctl: %s", SYSCTL_DDB_CAPTURE_DATA);
132 if (buflen == 0)
133 return;
134 buffer = malloc(buflen);
135 if (buffer == NULL)
136 err(EX_OSERR, "malloc");
137 bzero(buffer, buflen);
138 len = 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);
142 if (ret < 0) {
143 free(buffer);
144 goto repeat;
145 }
146
147 printf("%s\n", buffer);
148 free(buffer);
149 }
150
151 static void
ddb_capture_status_kvm(kvm_t * kvm)152 ddb_capture_status_kvm(kvm_t *kvm)
153 {
154 u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
155
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");
168 else
169 printf("capture is off\n");
170
171 }
172
173 static void
ddb_capture_status_sysctl(void)174 ddb_capture_status_sysctl(void)
175 {
176 u_int db_capture_bufoff, db_capture_bufsize, db_capture_inprogress;
177 size_t len;
178
179 len = sizeof(db_capture_bufoff);
180 if (sysctlbyname(SYSCTL_DDB_CAPTURE_BUFOFF, &db_capture_bufoff, &len,
181 NULL, 0) < 0)
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,
185 &len, NULL, 0) < 0)
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");
194 else
195 printf("capture is off\n");
196 }
197
198 void
ddb_capture(int argc,char * argv[])199 ddb_capture(int argc, char *argv[])
200 {
201 char *mflag, *nflag, errbuf[_POSIX2_LINE_MAX];
202 kvm_t *kvm;
203 int ch;
204
205 mflag = NULL;
206 nflag = NULL;
207 kvm = NULL;
208 while ((ch = getopt(argc, argv, "M:N:")) != -1) {
209 switch (ch) {
210 case 'M':
211 mflag = optarg;
212 break;
213
214 case 'N':
215 nflag = optarg;
216 break;
217
218 default:
219 usage();
220 }
221 }
222 argc -= optind;
223 argv += optind;
224
225 if (argc != 1)
226 usage();
227
228 if (mflag != NULL) {
229 kvm = kvm_openfiles(nflag, mflag, NULL, O_RDONLY, errbuf);
230 if (kvm == NULL)
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)
235 usage();
236 if (strcmp(argv[0], "print") == 0) {
237 if (kvm != NULL)
238 ddb_capture_print_kvm(kvm);
239 else
240 ddb_capture_print_sysctl();
241 } else if (strcmp(argv[0], "status") == 0) {
242 if (kvm != NULL)
243 ddb_capture_status_kvm(kvm);
244 else
245 ddb_capture_status_sysctl();
246 } else
247 usage();
248 }
249