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/systm.h> 40 #include <sys/pcpu.h> 41 #include <sys/smp.h> 42 #include <sys/sysent.h> 43 44 #include <net/vnet.h> 45 46 #include <ddb/ddb.h> 47 #include <ddb/db_sym.h> 48 #include <ddb/db_variables.h> 49 50 #include "opt_ddb.h" 51 52 /* 53 * Multiple symbol tables 54 */ 55 #ifndef MAXNOSYMTABS 56 #define MAXNOSYMTABS 3 /* mach, ux, emulator */ 57 #endif 58 59 static db_symtab_t db_symtabs[MAXNOSYMTABS] = {{0,},}; 60 static int db_nsymtab = 0; 61 62 static db_symtab_t *db_last_symtab; /* where last symbol was found */ 63 64 static c_db_sym_t db_lookup( const char *symstr); 65 static char *db_qualify(c_db_sym_t sym, char *symtabname); 66 static bool db_symbol_is_ambiguous(c_db_sym_t sym); 67 static bool db_line_at_pc(c_db_sym_t, char **, int *, db_expr_t); 68 69 static int db_cpu = -1; 70 71 #ifdef VIMAGE 72 static void *db_vnet = NULL; 73 #endif 74 75 /* 76 * Validate the CPU number used to interpret per-CPU variables so we can 77 * avoid later confusion if an invalid CPU is requested. 78 */ 79 int 80 db_var_db_cpu(struct db_variable *vp, db_expr_t *valuep, int op) 81 { 82 83 switch (op) { 84 case DB_VAR_GET: 85 *valuep = db_cpu; 86 return (1); 87 88 case DB_VAR_SET: 89 if (*(int *)valuep < -1 || *(int *)valuep > mp_maxid) { 90 db_printf("Invalid value: %d\n", *(int*)valuep); 91 return (0); 92 } 93 db_cpu = *(int *)valuep; 94 return (1); 95 96 default: 97 db_printf("db_var_db_cpu: unknown operation\n"); 98 return (0); 99 } 100 } 101 102 /* 103 * Read-only variable reporting the current CPU, which is what we use when 104 * db_cpu is set to -1. 105 */ 106 int 107 db_var_curcpu(struct db_variable *vp, db_expr_t *valuep, int op) 108 { 109 110 switch (op) { 111 case DB_VAR_GET: 112 *valuep = curcpu; 113 return (1); 114 115 case DB_VAR_SET: 116 db_printf("Read-only variable.\n"); 117 return (0); 118 119 default: 120 db_printf("db_var_curcpu: unknown operation\n"); 121 return (0); 122 } 123 } 124 125 #ifdef VIMAGE 126 /* 127 * Validate the virtual network pointer used to interpret per-vnet global 128 * variable expansion. Right now we don't do much here, really we should 129 * walk the global vnet list to check it's an OK pointer. 130 */ 131 int 132 db_var_db_vnet(struct db_variable *vp, db_expr_t *valuep, int op) 133 { 134 135 switch (op) { 136 case DB_VAR_GET: 137 *valuep = (db_expr_t)db_vnet; 138 return (1); 139 140 case DB_VAR_SET: 141 db_vnet = *(void **)valuep; 142 return (1); 143 144 default: 145 db_printf("db_var_db_vnet: unknown operation\n"); 146 return (0); 147 } 148 } 149 150 /* 151 * Read-only variable reporting the current vnet, which is what we use when 152 * db_vnet is set to NULL. 153 */ 154 int 155 db_var_curvnet(struct db_variable *vp, db_expr_t *valuep, int op) 156 { 157 158 switch (op) { 159 case DB_VAR_GET: 160 *valuep = (db_expr_t)curvnet; 161 return (1); 162 163 case DB_VAR_SET: 164 db_printf("Read-only variable.\n"); 165 return (0); 166 167 default: 168 db_printf("db_var_curvnet: unknown operation\n"); 169 return (0); 170 } 171 } 172 #endif 173 174 /* 175 * Add symbol table, with given name, to list of symbol tables. 176 */ 177 void 178 db_add_symbol_table(char *start, char *end, char *name, char *ref) 179 { 180 if (db_nsymtab >= MAXNOSYMTABS) { 181 printf ("No slots left for %s symbol table", name); 182 panic ("db_sym.c: db_add_symbol_table"); 183 } 184 185 db_symtabs[db_nsymtab].start = start; 186 db_symtabs[db_nsymtab].end = end; 187 db_symtabs[db_nsymtab].name = name; 188 db_symtabs[db_nsymtab].private = ref; 189 db_nsymtab++; 190 } 191 192 /* 193 * db_qualify("vm_map", "ux") returns "unix:vm_map". 194 * 195 * Note: return value points to static data whose content is 196 * overwritten by each call... but in practice this seems okay. 197 */ 198 static char * 199 db_qualify(c_db_sym_t sym, char *symtabname) 200 { 201 const char *symname; 202 static char tmp[256]; 203 204 db_symbol_values(sym, &symname, 0); 205 snprintf(tmp, sizeof(tmp), "%s:%s", symtabname, symname); 206 return tmp; 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, sym; 376 377 /* 378 * The kernel will never map the first page, so any symbols in that 379 * range cannot refer to addresses. Some third-party assembly files 380 * define internal constants which appear in their symbol table. 381 * Avoiding the lookup for those symbols avoids replacing small offsets 382 * with those symbols during disassembly. 383 */ 384 if (val < PAGE_SIZE) { 385 *offp = 0; 386 return (C_DB_SYM_NULL); 387 } 388 389 ret = C_DB_SYM_NULL; 390 newdiff = diff = val; 391 for (i = 0; i < db_nsymtab; i++) { 392 sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff); 393 if ((uintmax_t)newdiff < (uintmax_t)diff) { 394 db_last_symtab = &db_symtabs[i]; 395 diff = newdiff; 396 ret = sym; 397 } 398 } 399 *offp = diff; 400 return ret; 401 } 402 403 /* 404 * Return name and value of a symbol 405 */ 406 void 407 db_symbol_values(c_db_sym_t sym, const char **namep, db_expr_t *valuep) 408 { 409 db_expr_t value; 410 411 if (sym == DB_SYM_NULL) { 412 *namep = NULL; 413 return; 414 } 415 416 X_db_symbol_values(db_last_symtab, sym, namep, &value); 417 418 if (db_symbol_is_ambiguous(sym)) 419 *namep = db_qualify(sym, db_last_symtab->name); 420 if (valuep) 421 *valuep = value; 422 } 423 424 /* 425 * Print a the closest symbol to value 426 * 427 * After matching the symbol according to the given strategy 428 * we print it in the name+offset format, provided the symbol's 429 * value is close enough (eg smaller than db_maxoff). 430 * We also attempt to print [filename:linenum] when applicable 431 * (eg for procedure names). 432 * 433 * If we could not find a reasonable name+offset representation, 434 * then we just print the value in hex. Small values might get 435 * bogus symbol associations, e.g. 3 might get some absolute 436 * value like _INCLUDE_VERSION or something, therefore we do 437 * not accept symbols whose value is "small" (and use plain hex). 438 */ 439 440 db_expr_t db_maxoff = 0x10000; 441 442 void 443 db_printsym(db_expr_t off, db_strategy_t strategy) 444 { 445 db_expr_t d; 446 char *filename; 447 const char *name; 448 int linenum; 449 c_db_sym_t cursym; 450 451 if (off < 0 && off >= -db_maxoff) { 452 db_printf("%+#lr", (long)off); 453 return; 454 } 455 cursym = db_search_symbol(off, strategy, &d); 456 db_symbol_values(cursym, &name, NULL); 457 if (name == NULL || d >= (db_addr_t)db_maxoff) { 458 db_printf("%#lr", (unsigned long)off); 459 return; 460 } 461 #ifdef DDB_NUMSYM 462 db_printf("%#lr = %s", (unsigned long)off, name); 463 #else 464 db_printf("%s", name); 465 #endif 466 if (d) 467 db_printf("+%+#lr", (long)d); 468 if (strategy == DB_STGY_PROC) { 469 if (db_line_at_pc(cursym, &filename, &linenum, off)) 470 db_printf(" [%s:%d]", filename, linenum); 471 } 472 } 473 474 static bool 475 db_line_at_pc(c_db_sym_t sym, char **filename, int *linenum, db_expr_t pc) 476 { 477 return (X_db_line_at_pc(db_last_symtab, sym, filename, linenum, pc)); 478 } 479 480 bool 481 db_sym_numargs(c_db_sym_t sym, int *nargp, char **argnames) 482 { 483 return (X_db_sym_numargs(db_last_symtab, sym, nargp, argnames)); 484 } 485 486 void 487 db_decode_syscall(int number, struct thread *td) 488 { 489 struct proc *p; 490 c_db_sym_t sym; 491 db_expr_t diff; 492 sy_call_t *f; 493 const char *symname; 494 495 db_printf(" (%d", number); 496 p = (td != NULL) ? td->td_proc : NULL; 497 if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) { 498 f = p->p_sysent->sv_table[number].sy_call; 499 sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff); 500 if (sym != DB_SYM_NULL && diff == 0) { 501 db_symbol_values(sym, &symname, NULL); 502 db_printf(", %s, %s", p->p_sysent->sv_name, symname); 503 } 504 } 505 db_printf(")"); 506 } 507