1 /* $NetBSD: db_variables.c,v 1.47 2020/03/10 15:58:37 christos Exp $ */
2
3 /*
4 * Mach Operating System
5 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
15 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
21 * School of Computer Science
22 * Carnegie Mellon University
23 * Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 */
28
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: db_variables.c,v 1.47 2020/03/10 15:58:37 christos Exp $");
31
32 #ifdef _KERNEL_OPT
33 #include "opt_ddbparam.h"
34 #endif
35
36 #include <sys/param.h>
37 #include <sys/proc.h>
38 #include <uvm/uvm_extern.h>
39 #include <sys/sysctl.h>
40
41 #include <ddb/ddb.h>
42 #include <ddb/ddbvar.h>
43
44 /*
45 * If this is non-zero, the DDB will be entered when the system
46 * panics. Initialize it so that it's patchable.
47 */
48 #ifndef DDB_ONPANIC
49 #define DDB_ONPANIC 1
50 #endif
51 int db_onpanic = DDB_ONPANIC;
52
53 /*
54 * Can DDB can be entered from the console?
55 */
56 #ifndef DDB_FROMCONSOLE
57 #define DDB_FROMCONSOLE 1
58 #endif
59 int db_fromconsole = DDB_FROMCONSOLE;
60
61 /*
62 * Output DDB output to the message buffer?
63 */
64 #ifndef DDB_TEE_MSGBUF
65 #define DDB_TEE_MSGBUF 0
66 #endif
67 int db_tee_msgbuf = DDB_TEE_MSGBUF;
68
69 #ifndef DDB_PANICSTACKFRAMES
70 #define DDB_PANICSTACKFRAMES 65535
71 #endif
72 int db_panicstackframes = DDB_PANICSTACKFRAMES;
73
74 #ifndef DDB_DUMPSTACK
75 #define DDB_DUMPSTACK 1
76 #endif
77 int db_dumpstack = DDB_DUMPSTACK;
78
79 static int db_rw_internal_variable(const struct db_variable *, db_expr_t *,
80 int);
81 static int db_find_variable(const struct db_variable **);
82
83 /* XXX must all be ints for sysctl. */
84 const struct db_variable db_vars[] = {
85 {
86 .name = "fromconsole",
87 .valuep = &db_fromconsole,
88 .fcn = db_rw_internal_variable,
89 .modif = NULL,
90 },
91 {
92 .name = "maxoff",
93 .valuep = &db_maxoff,
94 .fcn = db_rw_internal_variable,
95 .modif = NULL,
96 },
97 {
98 .name = "maxwidth",
99 .valuep = &db_max_width,
100 .fcn = db_rw_internal_variable,
101 .modif = NULL,
102 },
103 {
104 .name = "lines",
105 .valuep = &db_max_line,
106 .fcn = db_rw_internal_variable,
107 .modif = NULL,
108 },
109 {
110 .name = "onpanic",
111 .valuep = &db_onpanic,
112 .fcn = db_rw_internal_variable,
113 .modif = NULL,
114 },
115 {
116 .name = "panicstackframes",
117 .valuep = &db_panicstackframes,
118 .fcn = db_rw_internal_variable,
119 .modif = NULL,
120 },
121 {
122 .name = "dumpstack",
123 .valuep = &db_dumpstack,
124 .fcn = db_rw_internal_variable,
125 .modif = NULL,
126 },
127 {
128 .name = "radix",
129 .valuep = &db_radix,
130 .fcn = db_rw_internal_variable,
131 .modif = NULL,
132 },
133 {
134 .name = "tabstops",
135 .valuep = &db_tab_stop_width,
136 .fcn = db_rw_internal_variable,
137 .modif = NULL,
138 },
139 {
140 .name = "tee_msgbuf",
141 .valuep = &db_tee_msgbuf,
142 .fcn = db_rw_internal_variable,
143 .modif = NULL,
144 },
145 };
146 const struct db_variable * const db_evars = db_vars + __arraycount(db_vars);
147
148 /*
149 * ddb command line access to the DDB variables defined above.
150 */
151 static int
db_rw_internal_variable(const struct db_variable * vp,db_expr_t * valp,int rw)152 db_rw_internal_variable(const struct db_variable *vp, db_expr_t *valp, int rw)
153 {
154
155 if (rw == DB_VAR_GET)
156 *valp = *(int *)vp->valuep;
157 else
158 *(int *)vp->valuep = *valp;
159 return (0);
160 }
161
162 /*
163 * sysctl(3) access to the DDB variables defined above.
164 */
165 #ifdef _KERNEL
166 SYSCTL_SETUP(sysctl_ddb_setup, "sysctl ddb subtree setup")
167 {
168
169 sysctl_createv(clog, 0, NULL, NULL,
170 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
171 CTLTYPE_INT, "radix",
172 SYSCTL_DESCR("Input and output radix"),
173 NULL, 0, &db_radix, 0,
174 CTL_DDB, DDBCTL_RADIX, CTL_EOL);
175 sysctl_createv(clog, 0, NULL, NULL,
176 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
177 CTLTYPE_INT, "maxoff",
178 SYSCTL_DESCR("Maximum symbol offset"),
179 NULL, 0, &db_maxoff, 0,
180 CTL_DDB, DDBCTL_MAXOFF, CTL_EOL);
181 sysctl_createv(clog, 0, NULL, NULL,
182 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
183 CTLTYPE_INT, "maxwidth",
184 SYSCTL_DESCR("Maximum output line width"),
185 NULL, 0, &db_max_width, 0,
186 CTL_DDB, DDBCTL_MAXWIDTH, CTL_EOL);
187 sysctl_createv(clog, 0, NULL, NULL,
188 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
189 CTLTYPE_INT, "lines",
190 SYSCTL_DESCR("Number of display lines"),
191 NULL, 0, &db_max_line, 0,
192 CTL_DDB, DDBCTL_LINES, CTL_EOL);
193 sysctl_createv(clog, 0, NULL, NULL,
194 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
195 CTLTYPE_INT, "tabstops",
196 SYSCTL_DESCR("Output tab width"),
197 NULL, 0, &db_tab_stop_width, 0,
198 CTL_DDB, DDBCTL_TABSTOPS, CTL_EOL);
199 sysctl_createv(clog, 0, NULL, NULL,
200 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
201 CTLTYPE_INT, "onpanic",
202 SYSCTL_DESCR("Whether to enter ddb on a kernel panic"),
203 NULL, 0, &db_onpanic, 0,
204 CTL_DDB, DDBCTL_ONPANIC, CTL_EOL);
205 sysctl_createv(clog, 0, NULL, NULL,
206 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
207 CTLTYPE_INT, "fromconsole",
208 SYSCTL_DESCR("Whether ddb can be entered from the "
209 "console"),
210 NULL, 0, &db_fromconsole, 0,
211 CTL_DDB, DDBCTL_FROMCONSOLE, CTL_EOL);
212 sysctl_createv(clog, 0, NULL, NULL,
213 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
214 CTLTYPE_INT, "tee_msgbuf",
215 SYSCTL_DESCR("Whether to tee ddb output to the msgbuf"),
216 NULL, 0, &db_tee_msgbuf, 0,
217 CTL_DDB, CTL_CREATE, CTL_EOL);
218 sysctl_createv(clog, 0, NULL, NULL,
219 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
220 CTLTYPE_STRING, "commandonenter",
221 SYSCTL_DESCR("Command to be executed on each ddb enter"),
222 NULL, 0, db_cmd_on_enter, DB_LINE_MAXLEN,
223 CTL_DDB, CTL_CREATE, CTL_EOL);
224 sysctl_createv(clog, 0, NULL, NULL,
225 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
226 CTLTYPE_INT, "panicstackframes",
227 SYSCTL_DESCR("Number of stack frames to print on panic"),
228 NULL, 0, &db_panicstackframes, 0,
229 CTL_DDB, CTL_CREATE, CTL_EOL);
230 sysctl_createv(clog, 0, NULL, NULL,
231 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
232 CTLTYPE_INT, "dumpstack",
233 SYSCTL_DESCR("On panic print stack trace"),
234 NULL, 0, &db_dumpstack, 0,
235 CTL_DDB, CTL_CREATE, CTL_EOL);
236 }
237 #endif /* _KERNEL */
238
239 int
db_find_variable(const struct db_variable ** varp)240 db_find_variable(const struct db_variable **varp)
241 {
242 int t;
243 const struct db_variable *vp;
244
245 t = db_read_token();
246 if (t == tIDENT) {
247 for (vp = db_vars; vp < db_evars; vp++) {
248 if (!strcmp(db_tok_string, vp->name)) {
249 *varp = vp;
250 return (1);
251 }
252 }
253 #ifdef _KERNEL
254 for (vp = db_regs; vp < db_eregs; vp++) {
255 if (!strcmp(db_tok_string, vp->name)) {
256 *varp = vp;
257 return (1);
258 }
259 }
260 #endif
261 }
262 db_error("Unknown variable\n");
263 /*NOTREACHED*/
264 return 0;
265 }
266
267 int
db_get_variable(db_expr_t * valuep)268 db_get_variable(db_expr_t *valuep)
269 {
270 const struct db_variable *vp;
271
272 if (!db_find_variable(&vp))
273 return (0);
274
275 db_read_variable(vp, valuep);
276
277 return (1);
278 }
279
280 int
db_set_variable(db_expr_t value)281 db_set_variable(db_expr_t value)
282 {
283 const struct db_variable *vp;
284
285 if (!db_find_variable(&vp))
286 return (0);
287
288 db_write_variable(vp, &value);
289
290 return (1);
291 }
292
293
294 void
db_read_variable(const struct db_variable * vp,db_expr_t * valuep)295 db_read_variable(const struct db_variable *vp, db_expr_t *valuep)
296 {
297 int (*func)(const struct db_variable *, db_expr_t *, int) = vp->fcn;
298
299 if (func == FCN_NULL)
300 *valuep = *(db_expr_t *)vp->valuep;
301 else
302 (*func)(vp, valuep, DB_VAR_GET);
303 }
304
305 void
db_write_variable(const struct db_variable * vp,db_expr_t * valuep)306 db_write_variable(const struct db_variable *vp, db_expr_t *valuep)
307 {
308 int (*func)(const struct db_variable *, db_expr_t *, int) = vp->fcn;
309
310 if (func == FCN_NULL)
311 *(db_expr_t *)vp->valuep = *valuep;
312 else
313 (*func)(vp, valuep, DB_VAR_SET);
314 }
315
316 /*ARGSUSED*/
317 void
db_set_cmd(db_expr_t addr,bool have_addr,db_expr_t count,const char * modif)318 db_set_cmd(db_expr_t addr, bool have_addr,
319 db_expr_t count, const char *modif)
320 {
321 db_expr_t value;
322 db_expr_t old_value;
323 const struct db_variable *vp = NULL; /* XXX: GCC */
324 int t;
325
326 t = db_read_token();
327 if (t != tDOLLAR) {
328 db_error("Unknown variable\n");
329 /*NOTREACHED*/
330 }
331 if (!db_find_variable(&vp)) {
332 db_error("Unknown variable\n");
333 /*NOTREACHED*/
334 }
335
336 t = db_read_token();
337 if (t != tEQ)
338 db_unread_token(t);
339
340 if (!db_expression(&value)) {
341 db_error("No value\n");
342 /*NOTREACHED*/
343 }
344 if (db_read_token() != tEOL) {
345 db_error("?\n");
346 /*NOTREACHED*/
347 }
348
349 db_read_variable(vp, &old_value);
350 db_printf("$%s\t\t%s = ", vp->name, db_num_to_str(old_value));
351 db_printf("%s\n", db_num_to_str(value));
352 db_write_variable(vp, &value);
353 }
354