db_variables.c revision 139747 
1/*-
2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
4 * All Rights Reserved.
5 *
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
11 *
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
19 *  School of Computer Science
20 *  Carnegie Mellon University
21 *  Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
25 */
26/*
27 * 	Author: David B. Golub, Carnegie Mellon University
28 *	Date:	7/90
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD: head/sys/ddb/db_variables.c 139747 2005-01-06 01:34:41Z imp $");
33
34#include <sys/param.h>
35#include <sys/systm.h>
36
37#include <ddb/ddb.h>
38#include <ddb/db_lex.h>
39#include <ddb/db_variables.h>
40
41static int	db_find_variable(struct db_variable **varp);
42
43static struct db_variable db_vars[] = {
44	{ "radix",	&db_radix, FCN_NULL },
45	{ "maxoff",	&db_maxoff, FCN_NULL },
46	{ "maxwidth",	&db_max_width, FCN_NULL },
47	{ "tabstops",	&db_tab_stop_width, FCN_NULL },
48	{ "lines",	&db_lines_per_page, FCN_NULL },
49};
50static struct db_variable *db_evars =
51	db_vars + sizeof(db_vars)/sizeof(db_vars[0]);
52
53static int
54db_find_variable(struct db_variable **varp)
55{
56	struct db_variable *vp;
57	int t;
58
59	t = db_read_token();
60	if (t == tIDENT) {
61		for (vp = db_vars; vp < db_evars; vp++) {
62			if (!strcmp(db_tok_string, vp->name)) {
63				*varp = vp;
64				return (1);
65			}
66		}
67		for (vp = db_regs; vp < db_eregs; vp++) {
68			if (!strcmp(db_tok_string, vp->name)) {
69				*varp = vp;
70				return (1);
71			}
72		}
73	}
74	db_error("Unknown variable\n");
75	return (0);
76}
77
78int
79db_get_variable(db_expr_t *valuep)
80{
81	struct db_variable *vp;
82
83	if (!db_find_variable(&vp))
84		return (0);
85
86	return (db_read_variable(vp, valuep));
87}
88
89int
90db_set_variable(db_expr_t value)
91{
92	struct db_variable *vp;
93
94	if (!db_find_variable(&vp))
95		return (0);
96
97	return (db_write_variable(vp, value));
98}
99
100int
101db_read_variable(struct db_variable *vp, db_expr_t *valuep)
102{
103	db_varfcn_t *func = vp->fcn;
104
105	if (func == FCN_NULL) {
106		*valuep = *(vp->valuep);
107		return (1);
108	}
109	return ((*func)(vp, valuep, DB_VAR_GET));
110}
111
112int
113db_write_variable(struct db_variable *vp, db_expr_t value)
114{
115	db_varfcn_t *func = vp->fcn;
116
117	if (func == FCN_NULL) {
118		*(vp->valuep) = value;
119		return (1);
120	}
121	return ((*func)(vp, &value, DB_VAR_SET));
122}
123
124void
125db_set_cmd(db_expr_t dummy1, boolean_t dummy2, db_expr_t dummy3, char *dummy4)
126{
127	struct db_variable *vp;
128	db_expr_t value;
129	int t;
130
131	t = db_read_token();
132	if (t != tDOLLAR) {
133		db_error("Unknown variable\n");
134		return;
135	}
136	if (!db_find_variable(&vp)) {
137		db_error("Unknown variable\n");
138		return;
139	}
140
141	t = db_read_token();
142	if (t != tEQ)
143		db_unread_token(t);
144
145	if (!db_expression(&value)) {
146		db_error("No value\n");
147		return;
148	}
149	if (db_read_token() != tEOL)
150		db_error("?\n");
151
152	db_write_variable(vp, value);
153}
154