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 #include "opt_kstack_pages.h"
35
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/pcpu.h>
39 #include <sys/proc.h>
40 #include <sys/smp.h>
41 #include <sys/sysent.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
db_var_db_cpu(struct db_variable * vp,db_expr_t * valuep,int op)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
db_var_curcpu(struct db_variable * vp,db_expr_t * valuep,int op)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
db_var_db_vnet(struct db_variable * vp,db_expr_t * valuep,int op)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
db_var_curvnet(struct db_variable * vp,db_expr_t * valuep,int op)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
db_add_symbol_table(char * start,char * end,char * name,char * ref)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 *
db_qualify(c_db_sym_t sym,char * symtabname)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 bool
db_eqname(const char * src,const char * dst,int c)209 db_eqname(const char *src, const char *dst, int c)
210 {
211 if (!strcmp(src, dst))
212 return (true);
213 if (src[0] == c)
214 return (!strcmp(src+1,dst));
215 return (false);
216 }
217
218 bool
db_value_of_name(const char * name,db_expr_t * valuep)219 db_value_of_name(const char *name, db_expr_t *valuep)
220 {
221 c_db_sym_t sym;
222
223 sym = db_lookup(name);
224 if (sym == C_DB_SYM_NULL)
225 return (false);
226 db_symbol_values(sym, &name, valuep);
227 return (true);
228 }
229
230 bool
db_value_of_name_pcpu(const char * name,db_expr_t * valuep)231 db_value_of_name_pcpu(const char *name, db_expr_t *valuep)
232 {
233 static char tmp[256];
234 db_expr_t value;
235 c_db_sym_t sym;
236 int cpu;
237
238 if (db_cpu != -1)
239 cpu = db_cpu;
240 else
241 cpu = curcpu;
242 snprintf(tmp, sizeof(tmp), "pcpu_entry_%s", name);
243 sym = db_lookup(tmp);
244 if (sym == C_DB_SYM_NULL)
245 return (false);
246 db_symbol_values(sym, &name, &value);
247 if (value < DPCPU_START || value >= DPCPU_STOP)
248 return (false);
249 *valuep = (db_expr_t)((uintptr_t)value + dpcpu_off[cpu]);
250 return (true);
251 }
252
253 bool
db_value_of_name_vnet(const char * name,db_expr_t * valuep)254 db_value_of_name_vnet(const char *name, db_expr_t *valuep)
255 {
256 #ifdef VIMAGE
257 static char tmp[256];
258 db_expr_t value;
259 c_db_sym_t sym;
260 struct vnet *vnet;
261
262 if (db_vnet != NULL)
263 vnet = db_vnet;
264 else
265 vnet = curvnet;
266 snprintf(tmp, sizeof(tmp), "vnet_entry_%s", name);
267 sym = db_lookup(tmp);
268 if (sym == C_DB_SYM_NULL)
269 return (false);
270 db_symbol_values(sym, &name, &value);
271 if (value < VNET_START || value >= VNET_STOP)
272 return (false);
273 *valuep = (db_expr_t)((uintptr_t)value + vnet->vnet_data_base);
274 return (true);
275 #else
276 return (false);
277 #endif
278 }
279
280 /*
281 * Lookup a symbol.
282 * If the symbol has a qualifier (e.g., ux:vm_map),
283 * then only the specified symbol table will be searched;
284 * otherwise, all symbol tables will be searched.
285 */
286 static c_db_sym_t
db_lookup(const char * symstr)287 db_lookup(const char *symstr)
288 {
289 c_db_sym_t sp;
290 int i;
291 int symtab_start = 0;
292 int symtab_end = db_nsymtab;
293 const char *cp;
294
295 /*
296 * Look for, remove, and remember any symbol table specifier.
297 */
298 for (cp = symstr; *cp; cp++) {
299 if (*cp == ':') {
300 for (i = 0; i < db_nsymtab; i++) {
301 int n = strlen(db_symtabs[i].name);
302
303 if (
304 n == (cp - symstr) &&
305 strncmp(symstr, db_symtabs[i].name, n) == 0
306 ) {
307 symtab_start = i;
308 symtab_end = i + 1;
309 break;
310 }
311 }
312 if (i == db_nsymtab) {
313 db_error("invalid symbol table name");
314 }
315 symstr = cp+1;
316 }
317 }
318
319 /*
320 * Look in the specified set of symbol tables.
321 * Return on first match.
322 */
323 for (i = symtab_start; i < symtab_end; i++) {
324 sp = X_db_lookup(&db_symtabs[i], symstr);
325 if (sp) {
326 db_last_symtab = &db_symtabs[i];
327 return sp;
328 }
329 }
330 return 0;
331 }
332
333 /*
334 * If true, check across symbol tables for multiple occurrences
335 * of a name. Might slow things down quite a bit.
336 */
337 static volatile bool db_qualify_ambiguous_names = false;
338
339 /*
340 * Does this symbol name appear in more than one symbol table?
341 * Used by db_symbol_values to decide whether to qualify a symbol.
342 */
343 static bool
db_symbol_is_ambiguous(c_db_sym_t sym)344 db_symbol_is_ambiguous(c_db_sym_t sym)
345 {
346 const char *sym_name;
347 int i;
348 bool found_once = false;
349
350 if (!db_qualify_ambiguous_names)
351 return (false);
352
353 db_symbol_values(sym, &sym_name, 0);
354 for (i = 0; i < db_nsymtab; i++) {
355 if (X_db_lookup(&db_symtabs[i], sym_name)) {
356 if (found_once)
357 return (true);
358 found_once = true;
359 }
360 }
361 return (false);
362 }
363
364 /*
365 * Find the closest symbol to val, and return its name
366 * and the difference between val and the symbol found.
367 */
368 c_db_sym_t
db_search_symbol(db_addr_t val,db_strategy_t strategy,db_expr_t * offp)369 db_search_symbol(db_addr_t val, db_strategy_t strategy, db_expr_t *offp)
370 {
371 unsigned int diff;
372 size_t newdiff;
373 int i;
374 c_db_sym_t ret, sym;
375
376 /*
377 * The kernel will never map the first page, so any symbols in that
378 * range cannot refer to addresses. Some third-party assembly files
379 * define internal constants which appear in their symbol table.
380 * Avoiding the lookup for those symbols avoids replacing small offsets
381 * with those symbols during disassembly.
382 */
383 if (val < PAGE_SIZE) {
384 *offp = 0;
385 return (C_DB_SYM_NULL);
386 }
387
388 ret = C_DB_SYM_NULL;
389 newdiff = diff = val;
390 for (i = 0; i < db_nsymtab; i++) {
391 sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff);
392 if ((uintmax_t)newdiff < (uintmax_t)diff) {
393 db_last_symtab = &db_symtabs[i];
394 diff = newdiff;
395 ret = sym;
396 }
397 }
398 *offp = diff;
399 return ret;
400 }
401
402 /*
403 * Return name and value of a symbol
404 */
405 void
db_symbol_values(c_db_sym_t sym,const char ** namep,db_expr_t * valuep)406 db_symbol_values(c_db_sym_t sym, const char **namep, db_expr_t *valuep)
407 {
408 db_expr_t value;
409
410 if (sym == DB_SYM_NULL) {
411 *namep = NULL;
412 return;
413 }
414
415 X_db_symbol_values(db_last_symtab, sym, namep, &value);
416
417 if (db_symbol_is_ambiguous(sym))
418 *namep = db_qualify(sym, db_last_symtab->name);
419 if (valuep)
420 *valuep = value;
421 }
422
423 /*
424 * Print a the closest symbol to value
425 *
426 * After matching the symbol according to the given strategy
427 * we print it in the name+offset format, provided the symbol's
428 * value is close enough (eg smaller than db_maxoff).
429 * We also attempt to print [filename:linenum] when applicable
430 * (eg for procedure names).
431 *
432 * If we could not find a reasonable name+offset representation,
433 * then we just print the value in hex. Small values might get
434 * bogus symbol associations, e.g. 3 might get some absolute
435 * value like _INCLUDE_VERSION or something, therefore we do
436 * not accept symbols whose value is "small" (and use plain hex).
437 */
438
439 db_expr_t db_maxoff = 0x10000;
440
441 void
db_printsym(db_expr_t off,db_strategy_t strategy)442 db_printsym(db_expr_t off, db_strategy_t strategy)
443 {
444 db_expr_t d;
445 char *filename;
446 const char *name;
447 int linenum;
448 c_db_sym_t cursym;
449
450 if (off < 0 && off >= -db_maxoff) {
451 db_printf("%+#lr", (long)off);
452 return;
453 }
454 cursym = db_search_symbol(off, strategy, &d);
455 db_symbol_values(cursym, &name, NULL);
456 if (name == NULL || d >= (db_addr_t)db_maxoff) {
457 db_printf("%#lr", (unsigned long)off);
458 return;
459 }
460 #ifdef DDB_NUMSYM
461 db_printf("%#lr = %s", (unsigned long)off, name);
462 #else
463 db_printf("%s", name);
464 #endif
465 if (d)
466 db_printf("+%+#lr", (long)d);
467 if (strategy == DB_STGY_PROC) {
468 if (db_line_at_pc(cursym, &filename, &linenum, off))
469 db_printf(" [%s:%d]", filename, linenum);
470 }
471 }
472
473 static bool
db_line_at_pc(c_db_sym_t sym,char ** filename,int * linenum,db_expr_t pc)474 db_line_at_pc(c_db_sym_t sym, char **filename, int *linenum, db_expr_t pc)
475 {
476 return (X_db_line_at_pc(db_last_symtab, sym, filename, linenum, pc));
477 }
478
479 bool
db_sym_numargs(c_db_sym_t sym,int * nargp,char ** argnames)480 db_sym_numargs(c_db_sym_t sym, int *nargp, char **argnames)
481 {
482 return (X_db_sym_numargs(db_last_symtab, sym, nargp, argnames));
483 }
484
485 void
db_decode_syscall(struct thread * td,u_int number)486 db_decode_syscall(struct thread *td, u_int number)
487 {
488 struct proc *p;
489
490 db_printf(" (%u", number);
491 p = (td != NULL) ? td->td_proc : NULL;
492 if (p != NULL) {
493 db_printf(", %s, %s", p->p_sysent->sv_name,
494 syscallname(p, number));
495 }
496 db_printf(")");
497 }
498