xref: /freebsd/sys/ddb/db_sym.c (revision 2f02600abfddfc4e9f20dd384a2e729b451e16bd)
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("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/pcpu.h>
36 #include <sys/smp.h>
37 #include <sys/systm.h>
38 
39 #include <net/vnet.h>
40 
41 #include <ddb/ddb.h>
42 #include <ddb/db_sym.h>
43 #include <ddb/db_variables.h>
44 
45 #include <opt_ddb.h>
46 
47 /*
48  * Multiple symbol tables
49  */
50 #ifndef MAXNOSYMTABS
51 #define	MAXNOSYMTABS	3	/* mach, ux, emulator */
52 #endif
53 
54 static db_symtab_t	db_symtabs[MAXNOSYMTABS] = {{0,},};
55 static int db_nsymtab = 0;
56 
57 static db_symtab_t	*db_last_symtab; /* where last symbol was found */
58 
59 static c_db_sym_t	db_lookup( const char *symstr);
60 static char		*db_qualify(c_db_sym_t sym, char *symtabname);
61 static boolean_t	db_symbol_is_ambiguous(c_db_sym_t sym);
62 static boolean_t	db_line_at_pc(c_db_sym_t, char **, int *, db_expr_t);
63 
64 static int db_cpu = -1;
65 
66 #ifdef VIMAGE
67 static void *db_vnet = NULL;
68 #endif
69 
70 /*
71  * Validate the CPU number used to interpret per-CPU variables so we can
72  * avoid later confusion if an invalid CPU is requested.
73  */
74 int
75 db_var_db_cpu(struct db_variable *vp, db_expr_t *valuep, int op)
76 {
77 
78 	switch (op) {
79 	case DB_VAR_GET:
80 		*valuep = db_cpu;
81 		return (1);
82 
83 	case DB_VAR_SET:
84 		if (*(int *)valuep < -1 && *(int *)valuep > mp_maxid) {
85 			db_printf("Invalid value: %d", *(int*)valuep);
86 			return (0);
87 		}
88 		db_cpu = *(int *)valuep;
89 		return (1);
90 
91 	default:
92 		db_printf("db_var_db_cpu: unknown operation\n");
93 		return (0);
94 	}
95 }
96 
97 /*
98  * Read-only variable reporting the current CPU, which is what we use when
99  * db_cpu is set to -1.
100  */
101 int
102 db_var_curcpu(struct db_variable *vp, db_expr_t *valuep, int op)
103 {
104 
105 	switch (op) {
106 	case DB_VAR_GET:
107 		*valuep = curcpu;
108 		return (1);
109 
110 	case DB_VAR_SET:
111 		db_printf("Read-only variable.\n");
112 		return (0);
113 
114 	default:
115 		db_printf("db_var_curcpu: unknown operation\n");
116 		return (0);
117 	}
118 }
119 
120 #ifdef VIMAGE
121 /*
122  * Validate the virtual network pointer used to interpret per-vnet global
123  * variable expansion.  Right now we don't do much here, really we should
124  * walk the global vnet list to check it's an OK pointer.
125  */
126 int
127 db_var_db_vnet(struct db_variable *vp, db_expr_t *valuep, int op)
128 {
129 
130 	switch (op) {
131 	case DB_VAR_GET:
132 		*valuep = (db_expr_t)db_vnet;
133 		return (1);
134 
135 	case DB_VAR_SET:
136 		db_vnet = *(void **)valuep;
137 		return (1);
138 
139 	default:
140 		db_printf("db_var_db_vnet: unknown operation\n");
141 		return (0);
142 	}
143 }
144 
145 /*
146  * Read-only variable reporting the current vnet, which is what we use when
147  * db_vnet is set to NULL.
148  */
149 int
150 db_var_curvnet(struct db_variable *vp, db_expr_t *valuep, int op)
151 {
152 
153 	switch (op) {
154 	case DB_VAR_GET:
155 		*valuep = (db_expr_t)curvnet;
156 		return (1);
157 
158 	case DB_VAR_SET:
159 		db_printf("Read-only variable.\n");
160 		return (0);
161 
162 	default:
163 		db_printf("db_var_curcpu: unknown operation\n");
164 		return (0);
165 	}
166 }
167 #endif
168 
169 /*
170  * Add symbol table, with given name, to list of symbol tables.
171  */
172 void
173 db_add_symbol_table(start, end, name, ref)
174 	char *start;
175 	char *end;
176 	char *name;
177 	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(sym, symtabname)
199 	c_db_sym_t	sym;
200 	register char	*symtabname;
201 {
202 	const char	*symname;
203 	static char     tmp[256];
204 
205 	db_symbol_values(sym, &symname, 0);
206 	snprintf(tmp, sizeof(tmp), "%s:%s", symtabname, symname);
207 	return tmp;
208 }
209 
210 
211 boolean_t
212 db_eqname(src, dst, c)
213 	const char *src;
214 	const char *dst;
215 	int c;
216 {
217 	if (!strcmp(src, dst))
218 	    return (TRUE);
219 	if (src[0] == c)
220 	    return (!strcmp(src+1,dst));
221 	return (FALSE);
222 }
223 
224 boolean_t
225 db_value_of_name(name, valuep)
226 	const char	*name;
227 	db_expr_t	*valuep;
228 {
229 	c_db_sym_t	sym;
230 
231 	sym = db_lookup(name);
232 	if (sym == C_DB_SYM_NULL)
233 	    return (FALSE);
234 	db_symbol_values(sym, &name, valuep);
235 	return (TRUE);
236 }
237 
238 boolean_t
239 db_value_of_name_pcpu(name, valuep)
240 	const char	*name;
241 	db_expr_t	*valuep;
242 {
243 	static char     tmp[256];
244 	db_expr_t	value;
245 	c_db_sym_t	sym;
246 	int		cpu;
247 
248 	if (db_cpu != -1)
249 		cpu = db_cpu;
250 	else
251 		cpu = curcpu;
252 	snprintf(tmp, sizeof(tmp), "pcpu_entry_%s", name);
253 	sym = db_lookup(tmp);
254 	if (sym == C_DB_SYM_NULL)
255 		return (FALSE);
256 	db_symbol_values(sym, &name, &value);
257 	if (value < DPCPU_START || value >= DPCPU_STOP)
258 		return (FALSE);
259 	*valuep = (db_expr_t)((uintptr_t)value + dpcpu_off[cpu]);
260 	return (TRUE);
261 }
262 
263 boolean_t
264 db_value_of_name_vnet(name, valuep)
265 	const char	*name;
266 	db_expr_t	*valuep;
267 {
268 #ifdef VIMAGE
269 	static char     tmp[256];
270 	db_expr_t	value;
271 	c_db_sym_t	sym;
272 	struct vnet	*vnet;
273 
274 	if (db_vnet != NULL)
275 		vnet = db_vnet;
276 	else
277 		vnet = curvnet;
278 	snprintf(tmp, sizeof(tmp), "vnet_entry_%s", name);
279 	sym = db_lookup(tmp);
280 	if (sym == C_DB_SYM_NULL)
281 		return (FALSE);
282 	db_symbol_values(sym, &name, &value);
283 	if (value < VNET_START || value >= VNET_STOP)
284 		return (FALSE);
285 	*valuep = (db_expr_t)((uintptr_t)value + vnet->vnet_data_base);
286 	return (TRUE);
287 #else
288 	return (FALSE);
289 #endif
290 }
291 
292 /*
293  * Lookup a symbol.
294  * If the symbol has a qualifier (e.g., ux:vm_map),
295  * then only the specified symbol table will be searched;
296  * otherwise, all symbol tables will be searched.
297  */
298 static c_db_sym_t
299 db_lookup(symstr)
300 	const char *symstr;
301 {
302 	c_db_sym_t sp;
303 	register int i;
304 	int symtab_start = 0;
305 	int symtab_end = db_nsymtab;
306 	register const char *cp;
307 
308 	/*
309 	 * Look for, remove, and remember any symbol table specifier.
310 	 */
311 	for (cp = symstr; *cp; cp++) {
312 		if (*cp == ':') {
313 			for (i = 0; i < db_nsymtab; i++) {
314 				int n = strlen(db_symtabs[i].name);
315 
316 				if (
317 				    n == (cp - symstr) &&
318 				    strncmp(symstr, db_symtabs[i].name, n) == 0
319 				) {
320 					symtab_start = i;
321 					symtab_end = i + 1;
322 					break;
323 				}
324 			}
325 			if (i == db_nsymtab) {
326 				db_error("invalid symbol table name");
327 			}
328 			symstr = cp+1;
329 		}
330 	}
331 
332 	/*
333 	 * Look in the specified set of symbol tables.
334 	 * Return on first match.
335 	 */
336 	for (i = symtab_start; i < symtab_end; i++) {
337 		sp = X_db_lookup(&db_symtabs[i], symstr);
338 		if (sp) {
339 			db_last_symtab = &db_symtabs[i];
340 			return sp;
341 		}
342 	}
343 	return 0;
344 }
345 
346 /*
347  * If TRUE, check across symbol tables for multiple occurrences
348  * of a name.  Might slow things down quite a bit.
349  */
350 static volatile boolean_t db_qualify_ambiguous_names = FALSE;
351 
352 /*
353  * Does this symbol name appear in more than one symbol table?
354  * Used by db_symbol_values to decide whether to qualify a symbol.
355  */
356 static boolean_t
357 db_symbol_is_ambiguous(sym)
358 	c_db_sym_t	sym;
359 {
360 	const char	*sym_name;
361 	register int	i;
362 	register
363 	boolean_t	found_once = FALSE;
364 
365 	if (!db_qualify_ambiguous_names)
366 		return FALSE;
367 
368 	db_symbol_values(sym, &sym_name, 0);
369 	for (i = 0; i < db_nsymtab; i++) {
370 		if (X_db_lookup(&db_symtabs[i], sym_name)) {
371 			if (found_once)
372 				return TRUE;
373 			found_once = TRUE;
374 		}
375 	}
376 	return FALSE;
377 }
378 
379 /*
380  * Find the closest symbol to val, and return its name
381  * and the difference between val and the symbol found.
382  */
383 c_db_sym_t
384 db_search_symbol( val, strategy, offp)
385 	register db_addr_t	val;
386 	db_strategy_t		strategy;
387 	db_expr_t		*offp;
388 {
389 	register
390 	unsigned int	diff;
391 	size_t		newdiff;
392 	register int	i;
393 	c_db_sym_t	ret = C_DB_SYM_NULL, sym;
394 
395 	newdiff = diff = ~0;
396 	for (i = 0; i < db_nsymtab; i++) {
397 	    sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff);
398 	    if (newdiff < diff) {
399 		db_last_symtab = &db_symtabs[i];
400 		diff = newdiff;
401 		ret = sym;
402 	    }
403 	}
404 	*offp = diff;
405 	return ret;
406 }
407 
408 /*
409  * Return name and value of a symbol
410  */
411 void
412 db_symbol_values(sym, namep, valuep)
413 	c_db_sym_t	sym;
414 	const char	**namep;
415 	db_expr_t	*valuep;
416 {
417 	db_expr_t	value;
418 
419 	if (sym == DB_SYM_NULL) {
420 		*namep = 0;
421 		return;
422 	}
423 
424 	X_db_symbol_values(db_last_symtab, sym, namep, &value);
425 
426 	if (db_symbol_is_ambiguous(sym))
427 		*namep = db_qualify(sym, db_last_symtab->name);
428 	if (valuep)
429 		*valuep = value;
430 }
431 
432 
433 /*
434  * Print a the closest symbol to value
435  *
436  * After matching the symbol according to the given strategy
437  * we print it in the name+offset format, provided the symbol's
438  * value is close enough (eg smaller than db_maxoff).
439  * We also attempt to print [filename:linenum] when applicable
440  * (eg for procedure names).
441  *
442  * If we could not find a reasonable name+offset representation,
443  * then we just print the value in hex.  Small values might get
444  * bogus symbol associations, e.g. 3 might get some absolute
445  * value like _INCLUDE_VERSION or something, therefore we do
446  * not accept symbols whose value is "small" (and use plain hex).
447  */
448 
449 db_expr_t	db_maxoff = 0x10000;
450 
451 void
452 db_printsym(off, strategy)
453 	db_expr_t	off;
454 	db_strategy_t	strategy;
455 {
456 	db_expr_t	d;
457 	char 		*filename;
458 	const char	*name;
459 	db_expr_t	value;
460 	int 		linenum;
461 	c_db_sym_t	cursym;
462 
463 	cursym = db_search_symbol(off, strategy, &d);
464 	db_symbol_values(cursym, &name, &value);
465 	if (name == 0)
466 		value = off;
467 	if (value >= DB_SMALL_VALUE_MIN && value <= DB_SMALL_VALUE_MAX) {
468 		db_printf("%+#lr", (long)off);
469 		return;
470 	}
471 	if (name == 0 || d >= (unsigned long)db_maxoff) {
472 		db_printf("%#lr", (unsigned long)off);
473 		return;
474 	}
475 #ifdef DDB_NUMSYM
476 	db_printf("%#lr = %s", (unsigned long)off, name);
477 #else
478 	db_printf("%s", name);
479 #endif
480 	if (d)
481 		db_printf("+%+#lr", (long)d);
482 	if (strategy == DB_STGY_PROC) {
483 		if (db_line_at_pc(cursym, &filename, &linenum, off))
484 			db_printf(" [%s:%d]", filename, linenum);
485 	}
486 }
487 
488 static boolean_t
489 db_line_at_pc( sym, filename, linenum, pc)
490 	c_db_sym_t	sym;
491 	char		**filename;
492 	int		*linenum;
493 	db_expr_t	pc;
494 {
495 	return X_db_line_at_pc( db_last_symtab, sym, filename, linenum, pc);
496 }
497 
498 int
499 db_sym_numargs(sym, nargp, argnames)
500 	c_db_sym_t	sym;
501 	int		*nargp;
502 	char		**argnames;
503 {
504 	return X_db_sym_numargs(db_last_symtab, sym, nargp, argnames);
505 }
506