1 /* $OpenBSD: db_sym.c,v 1.57 2024/11/07 16:02:29 miod Exp $ */
2 /* $NetBSD: db_sym.c,v 1.24 2000/08/11 22:50:47 tv Exp $ */
3
4 /*
5 * Mach Operating System
6 * Copyright (c) 1993,1992,1991,1990 Carnegie Mellon University
7 * All Rights Reserved.
8 *
9 * Permission to use, copy, modify and distribute this software and its
10 * documentation is hereby granted, provided that both the copyright
11 * notice and this permission notice appear in all copies of the
12 * software, derivative works or modified versions, and any portions
13 * thereof, and that both notices appear in supporting documentation.
14 *
15 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
16 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
17 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
18 *
19 * Carnegie Mellon requests users of this software to return to
20 *
21 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
22 * School of Computer Science
23 * Carnegie Mellon University
24 * Pittsburgh PA 15213-3890
25 *
26 * any improvements or extensions that they make and grant Carnegie Mellon
27 * the rights to redistribute these changes.
28 */
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32
33 #include <machine/db_machdep.h>
34
35 #include <ddb/db_lex.h>
36 #include <ddb/db_sym.h>
37 #include <ddb/db_output.h>
38 #include <ddb/db_command.h>
39
40 extern char end[];
41
42 /*
43 * Initialize the kernel debugger by initializing the master symbol
44 * table. Note that if initializing the master symbol table fails,
45 * no other symbol tables can be loaded.
46 */
47 void
ddb_init(void)48 ddb_init(void)
49 {
50 const char *name = "bsd";
51 extern char *esym;
52 #if defined(__sparc64__) || defined(__mips__) || defined(__amd64__) || \
53 defined(__i386__)
54 extern char *ssym;
55 #endif
56 char *xssym, *xesym;
57
58 xesym = esym;
59 #if defined(__sparc64__) || defined(__mips__) || defined(__amd64__) || \
60 defined(__i386__)
61 xssym = ssym;
62 #else
63 xssym = (char *)&end;
64 #endif
65 /*
66 * Do this check now for the master symbol table to avoid printing
67 * the message N times.
68 */
69 if ((((vaddr_t)xssym) & (sizeof(long) - 1)) != 0) {
70 printf("[ %s symbol table has bad start address %p ]\n",
71 name, xssym);
72 return;
73 }
74
75 if (xesym != NULL && xesym != xssym) {
76 if (db_elf_sym_init((vaddr_t)xesym - (vaddr_t)xssym, xssym,
77 xesym, name) == 1)
78 return;
79 }
80
81 printf("[ no symbol table formats found ]\n");
82 }
83
84 int
db_eqname(const char * src,const char * dst,int c)85 db_eqname(const char *src, const char *dst, int c)
86 {
87 if (!strcmp(src, dst))
88 return (1);
89 if (src[0] == c)
90 return (!strcmp(src+1,dst));
91 return (0);
92 }
93
94 /*
95 * Find the closest symbol to val, and return its name
96 * and the difference between val and the symbol found.
97 */
98 Elf_Sym *
db_search_symbol(vaddr_t val,db_strategy_t strategy,db_expr_t * offp)99 db_search_symbol(vaddr_t val, db_strategy_t strategy, db_expr_t *offp)
100 {
101 unsigned int diff;
102 db_expr_t newdiff;
103 Elf_Sym *ret = NULL, *sym;
104
105 newdiff = diff = ~0;
106 sym = db_elf_sym_search(val, strategy, &newdiff);
107 if (newdiff < diff) {
108 diff = newdiff;
109 ret = sym;
110 }
111 *offp = diff;
112 return ret;
113 }
114
115 /*
116 * Print the closest symbol to a value.
117 *
118 * After matching the symbol according to the given strategy
119 * we print it in the name+offset format, provided the symbol's
120 * value is close enough (eg smaller than db_maxoff).
121 * We also attempt to print [filename:linenum] when applicable
122 * (eg for procedure names).
123 *
124 * If we could not find a reasonable name+offset representation,
125 * then we just print the value in hex. Small values might get
126 * bogus symbol associations, e.g. 3 might get some absolute
127 * value like _INCLUDE_VERSION or something, therefore we do
128 * not accept symbols whose value is zero (and use plain hex).
129 * Also, avoid printing as "end+0x????" which is useless.
130 * The variable db_lastsym is used instead of "end" in case we
131 * add support for symbols in loadable driver modules.
132 */
133 unsigned long db_lastsym = (unsigned long)end;
134 unsigned int db_maxoff = 0x10000000;
135
136
137 void
db_printsym(db_expr_t off,db_strategy_t strategy,int (* pr)(const char *,...))138 db_printsym(db_expr_t off, db_strategy_t strategy,
139 int (*pr)(const char *, ...))
140 {
141 db_expr_t d;
142 const char *filename;
143 const char *name;
144 db_expr_t value;
145 int linenum;
146 Elf_Sym *cursym;
147 char buf[DB_FORMAT_BUF_SIZE];
148
149 if (off <= db_lastsym) {
150 cursym = db_search_symbol(off, strategy, &d);
151 db_symbol_values(cursym, &name, &value);
152 if (name && (d < db_maxoff) && value) {
153 (*pr)("%s", name);
154 if (d) {
155 (*pr)("+%s", db_format(buf, sizeof(buf),
156 d, DB_FORMAT_R, 1, 0));
157 }
158 if (strategy == DB_STGY_PROC) {
159 if (db_elf_line_at_pc(cursym, &filename,
160 &linenum, off))
161 (*pr)(" [%s:%d]", filename, linenum);
162 }
163 return;
164 }
165 }
166
167 (*pr)("%s", db_format(buf, sizeof(buf), off, DB_FORMAT_N, 1, 0));
168 return;
169 }
170