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 bool 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 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 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 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 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 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 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 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 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 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 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