FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_sym.c
1 /*-
2 * SPDX-License-Identifier: MIT-CMU
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
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 * Author: David B. Golub, Carnegie Mellon University
30 * Date: 7/90
31 */
32
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35
36 #include "opt_kstack_pages.h"
37
38 #include <sys/param.h>
39 #include <sys/pcpu.h>
40 #include <sys/smp.h>
41 #include <sys/systm.h>
42
43 #include <net/vnet.h>
44
45 #include <ddb/ddb.h>
46 #include <ddb/db_sym.h>
47 #include <ddb/db_variables.h>
48
49 #include "opt_ddb.h"
50
51 /*
52 * Multiple symbol tables
53 */
54 #ifndef MAXNOSYMTABS
55 #define MAXNOSYMTABS 3 /* mach, ux, emulator */
56 #endif
57
58 static db_symtab_t db_symtabs[MAXNOSYMTABS] = {{0,},};
59 static int db_nsymtab = 0;
60
61 static db_symtab_t *db_last_symtab; /* where last symbol was found */
62
63 static c_db_sym_t db_lookup( const char *symstr);
64 static char *db_qualify(c_db_sym_t sym, char *symtabname);
65 static bool db_symbol_is_ambiguous(c_db_sym_t sym);
66 static bool db_line_at_pc(c_db_sym_t, char **, int *, db_expr_t);
67
68 static int db_cpu = -1;
69
70 #ifdef VIMAGE
71 static void *db_vnet = NULL;
72 #endif
73
74 /*
75 * Validate the CPU number used to interpret per-CPU variables so we can
76 * avoid later confusion if an invalid CPU is requested.
77 */
78 int
79 db_var_db_cpu(struct db_variable *vp, db_expr_t *valuep, int op)
80 {
81
82 switch (op) {
83 case DB_VAR_GET:
84 *valuep = db_cpu;
85 return (1);
86
87 case DB_VAR_SET:
88 if (*(int *)valuep < -1 || *(int *)valuep > mp_maxid) {
89 db_printf("Invalid value: %d\n", *(int*)valuep);
90 return (0);
91 }
92 db_cpu = *(int *)valuep;
93 return (1);
94
95 default:
96 db_printf("db_var_db_cpu: unknown operation\n");
97 return (0);
98 }
99 }
100
101 /*
102 * Read-only variable reporting the current CPU, which is what we use when
103 * db_cpu is set to -1.
104 */
105 int
106 db_var_curcpu(struct db_variable *vp, db_expr_t *valuep, int op)
107 {
108
109 switch (op) {
110 case DB_VAR_GET:
111 *valuep = curcpu;
112 return (1);
113
114 case DB_VAR_SET:
115 db_printf("Read-only variable.\n");
116 return (0);
117
118 default:
119 db_printf("db_var_curcpu: unknown operation\n");
120 return (0);
121 }
122 }
123
124 #ifdef VIMAGE
125 /*
126 * Validate the virtual network pointer used to interpret per-vnet global
127 * variable expansion. Right now we don't do much here, really we should
128 * walk the global vnet list to check it's an OK pointer.
129 */
130 int
131 db_var_db_vnet(struct db_variable *vp, db_expr_t *valuep, int op)
132 {
133
134 switch (op) {
135 case DB_VAR_GET:
136 *valuep = (db_expr_t)db_vnet;
137 return (1);
138
139 case DB_VAR_SET:
140 db_vnet = *(void **)valuep;
141 return (1);
142
143 default:
144 db_printf("db_var_db_vnet: unknown operation\n");
145 return (0);
146 }
147 }
148
149 /*
150 * Read-only variable reporting the current vnet, which is what we use when
151 * db_vnet is set to NULL.
152 */
153 int
154 db_var_curvnet(struct db_variable *vp, db_expr_t *valuep, int op)
155 {
156
157 switch (op) {
158 case DB_VAR_GET:
159 *valuep = (db_expr_t)curvnet;
160 return (1);
161
162 case DB_VAR_SET:
163 db_printf("Read-only variable.\n");
164 return (0);
165
166 default:
167 db_printf("db_var_curvnet: unknown operation\n");
168 return (0);
169 }
170 }
171 #endif
172
173 /*
174 * Add symbol table, with given name, to list of symbol tables.
175 */
176 void
177 db_add_symbol_table(char *start, char *end, char *name, char *ref)
178 {
179 if (db_nsymtab >= MAXNOSYMTABS) {
180 printf ("No slots left for %s symbol table", name);
181 panic ("db_sym.c: db_add_symbol_table");
182 }
183
184 db_symtabs[db_nsymtab].start = start;
185 db_symtabs[db_nsymtab].end = end;
186 db_symtabs[db_nsymtab].name = name;
187 db_symtabs[db_nsymtab].private = ref;
188 db_nsymtab++;
189 }
190
191 /*
192 * db_qualify("vm_map", "ux") returns "unix:vm_map".
193 *
194 * Note: return value points to static data whose content is
195 * overwritten by each call... but in practice this seems okay.
196 */
197 static char *
198 db_qualify(c_db_sym_t sym, char *symtabname)
199 {
200 const char *symname;
201 static char tmp[256];
202
203 db_symbol_values(sym, &symname, 0);
204 snprintf(tmp, sizeof(tmp), "%s:%s", symtabname, symname);
205 return tmp;
206 }
207
208
209 bool
210 db_eqname(const char *src, const char *dst, int c)
211 {
212 if (!strcmp(src, dst))
213 return (true);
214 if (src[0] == c)
215 return (!strcmp(src+1,dst));
216 return (false);
217 }
218
219 bool
220 db_value_of_name(const char *name, db_expr_t *valuep)
221 {
222 c_db_sym_t sym;
223
224 sym = db_lookup(name);
225 if (sym == C_DB_SYM_NULL)
226 return (false);
227 db_symbol_values(sym, &name, valuep);
228 return (true);
229 }
230
231 bool
232 db_value_of_name_pcpu(const char *name, db_expr_t *valuep)
233 {
234 static char tmp[256];
235 db_expr_t value;
236 c_db_sym_t sym;
237 int cpu;
238
239 if (db_cpu != -1)
240 cpu = db_cpu;
241 else
242 cpu = curcpu;
243 snprintf(tmp, sizeof(tmp), "pcpu_entry_%s", name);
244 sym = db_lookup(tmp);
245 if (sym == C_DB_SYM_NULL)
246 return (false);
247 db_symbol_values(sym, &name, &value);
248 if (value < DPCPU_START || value >= DPCPU_STOP)
249 return (false);
250 *valuep = (db_expr_t)((uintptr_t)value + dpcpu_off[cpu]);
251 return (true);
252 }
253
254 bool
255 db_value_of_name_vnet(const char *name, db_expr_t *valuep)
256 {
257 #ifdef VIMAGE
258 static char tmp[256];
259 db_expr_t value;
260 c_db_sym_t sym;
261 struct vnet *vnet;
262
263 if (db_vnet != NULL)
264 vnet = db_vnet;
265 else
266 vnet = curvnet;
267 snprintf(tmp, sizeof(tmp), "vnet_entry_%s", name);
268 sym = db_lookup(tmp);
269 if (sym == C_DB_SYM_NULL)
270 return (false);
271 db_symbol_values(sym, &name, &value);
272 if (value < VNET_START || value >= VNET_STOP)
273 return (false);
274 *valuep = (db_expr_t)((uintptr_t)value + vnet->vnet_data_base);
275 return (true);
276 #else
277 return (false);
278 #endif
279 }
280
281 /*
282 * Lookup a symbol.
283 * If the symbol has a qualifier (e.g., ux:vm_map),
284 * then only the specified symbol table will be searched;
285 * otherwise, all symbol tables will be searched.
286 */
287 static c_db_sym_t
288 db_lookup(const char *symstr)
289 {
290 c_db_sym_t sp;
291 int i;
292 int symtab_start = 0;
293 int symtab_end = db_nsymtab;
294 const char *cp;
295
296 /*
297 * Look for, remove, and remember any symbol table specifier.
298 */
299 for (cp = symstr; *cp; cp++) {
300 if (*cp == ':') {
301 for (i = 0; i < db_nsymtab; i++) {
302 int n = strlen(db_symtabs[i].name);
303
304 if (
305 n == (cp - symstr) &&
306 strncmp(symstr, db_symtabs[i].name, n) == 0
307 ) {
308 symtab_start = i;
309 symtab_end = i + 1;
310 break;
311 }
312 }
313 if (i == db_nsymtab) {
314 db_error("invalid symbol table name");
315 }
316 symstr = cp+1;
317 }
318 }
319
320 /*
321 * Look in the specified set of symbol tables.
322 * Return on first match.
323 */
324 for (i = symtab_start; i < symtab_end; i++) {
325 sp = X_db_lookup(&db_symtabs[i], symstr);
326 if (sp) {
327 db_last_symtab = &db_symtabs[i];
328 return sp;
329 }
330 }
331 return 0;
332 }
333
334 /*
335 * If true, check across symbol tables for multiple occurrences
336 * of a name. Might slow things down quite a bit.
337 */
338 static volatile bool db_qualify_ambiguous_names = false;
339
340 /*
341 * Does this symbol name appear in more than one symbol table?
342 * Used by db_symbol_values to decide whether to qualify a symbol.
343 */
344 static bool
345 db_symbol_is_ambiguous(c_db_sym_t sym)
346 {
347 const char *sym_name;
348 int i;
349 bool found_once = false;
350
351 if (!db_qualify_ambiguous_names)
352 return (false);
353
354 db_symbol_values(sym, &sym_name, 0);
355 for (i = 0; i < db_nsymtab; i++) {
356 if (X_db_lookup(&db_symtabs[i], sym_name)) {
357 if (found_once)
358 return (true);
359 found_once = true;
360 }
361 }
362 return (false);
363 }
364
365 /*
366 * Find the closest symbol to val, and return its name
367 * and the difference between val and the symbol found.
368 */
369 c_db_sym_t
370 db_search_symbol(db_addr_t val, db_strategy_t strategy, db_expr_t *offp)
371 {
372 unsigned int diff;
373 size_t newdiff;
374 int i;
375 c_db_sym_t ret = C_DB_SYM_NULL, sym;
376
377 newdiff = diff = val;
378 for (i = 0; i < db_nsymtab; i++) {
379 sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff);
380 if ((uintmax_t)newdiff < (uintmax_t)diff) {
381 db_last_symtab = &db_symtabs[i];
382 diff = newdiff;
383 ret = sym;
384 }
385 }
386 *offp = diff;
387 return ret;
388 }
389
390 /*
391 * Return name and value of a symbol
392 */
393 void
394 db_symbol_values(c_db_sym_t sym, const char **namep, db_expr_t *valuep)
395 {
396 db_expr_t value;
397
398 if (sym == DB_SYM_NULL) {
399 *namep = NULL;
400 return;
401 }
402
403 X_db_symbol_values(db_last_symtab, sym, namep, &value);
404
405 if (db_symbol_is_ambiguous(sym))
406 *namep = db_qualify(sym, db_last_symtab->name);
407 if (valuep)
408 *valuep = value;
409 }
410
411
412 /*
413 * Print a the closest symbol to value
414 *
415 * After matching the symbol according to the given strategy
416 * we print it in the name+offset format, provided the symbol's
417 * value is close enough (eg smaller than db_maxoff).
418 * We also attempt to print [filename:linenum] when applicable
419 * (eg for procedure names).
420 *
421 * If we could not find a reasonable name+offset representation,
422 * then we just print the value in hex. Small values might get
423 * bogus symbol associations, e.g. 3 might get some absolute
424 * value like _INCLUDE_VERSION or something, therefore we do
425 * not accept symbols whose value is "small" (and use plain hex).
426 */
427
428 db_expr_t db_maxoff = 0x10000;
429
430 void
431 db_printsym(db_expr_t off, db_strategy_t strategy)
432 {
433 db_expr_t d;
434 char *filename;
435 const char *name;
436 int linenum;
437 c_db_sym_t cursym;
438
439 if (off < 0 && off >= -db_maxoff) {
440 db_printf("%+#lr", (long)off);
441 return;
442 }
443 cursym = db_search_symbol(off, strategy, &d);
444 db_symbol_values(cursym, &name, NULL);
445 if (name == NULL || d >= (db_addr_t)db_maxoff) {
446 db_printf("%#lr", (unsigned long)off);
447 return;
448 }
449 #ifdef DDB_NUMSYM
450 db_printf("%#lr = %s", (unsigned long)off, name);
451 #else
452 db_printf("%s", name);
453 #endif
454 if (d)
455 db_printf("+%+#lr", (long)d);
456 if (strategy == DB_STGY_PROC) {
457 if (db_line_at_pc(cursym, &filename, &linenum, off))
458 db_printf(" [%s:%d]", filename, linenum);
459 }
460 }
461
462 static bool
463 db_line_at_pc(c_db_sym_t sym, char **filename, int *linenum, db_expr_t pc)
464 {
465 return (X_db_line_at_pc(db_last_symtab, sym, filename, linenum, pc));
466 }
467
468 bool
469 db_sym_numargs(c_db_sym_t sym, int *nargp, char **argnames)
470 {
471 return (X_db_sym_numargs(db_last_symtab, sym, nargp, argnames));
472 }
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