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/proc.h> 42 #include <sys/smp.h> 43 #include <sys/sysent.h> 44 45 #include <net/vnet.h> 46 47 #include <ddb/ddb.h> 48 #include <ddb/db_sym.h> 49 #include <ddb/db_variables.h> 50 51 #include "opt_ddb.h" 52 53 /* 54 * Multiple symbol tables 55 */ 56 #ifndef MAXNOSYMTABS 57 #define MAXNOSYMTABS 3 /* mach, ux, emulator */ 58 #endif 59 60 static db_symtab_t db_symtabs[MAXNOSYMTABS] = {{0,},}; 61 static int db_nsymtab = 0; 62 63 static db_symtab_t *db_last_symtab; /* where last symbol was found */ 64 65 static c_db_sym_t db_lookup( const char *symstr); 66 static char *db_qualify(c_db_sym_t sym, char *symtabname); 67 static bool db_symbol_is_ambiguous(c_db_sym_t sym); 68 static bool db_line_at_pc(c_db_sym_t, char **, int *, db_expr_t); 69 70 static int db_cpu = -1; 71 72 #ifdef VIMAGE 73 static void *db_vnet = NULL; 74 #endif 75 76 /* 77 * Validate the CPU number used to interpret per-CPU variables so we can 78 * avoid later confusion if an invalid CPU is requested. 79 */ 80 int 81 db_var_db_cpu(struct db_variable *vp, db_expr_t *valuep, int op) 82 { 83 84 switch (op) { 85 case DB_VAR_GET: 86 *valuep = db_cpu; 87 return (1); 88 89 case DB_VAR_SET: 90 if (*(int *)valuep < -1 || *(int *)valuep > mp_maxid) { 91 db_printf("Invalid value: %d\n", *(int*)valuep); 92 return (0); 93 } 94 db_cpu = *(int *)valuep; 95 return (1); 96 97 default: 98 db_printf("db_var_db_cpu: unknown operation\n"); 99 return (0); 100 } 101 } 102 103 /* 104 * Read-only variable reporting the current CPU, which is what we use when 105 * db_cpu is set to -1. 106 */ 107 int 108 db_var_curcpu(struct db_variable *vp, db_expr_t *valuep, int op) 109 { 110 111 switch (op) { 112 case DB_VAR_GET: 113 *valuep = curcpu; 114 return (1); 115 116 case DB_VAR_SET: 117 db_printf("Read-only variable.\n"); 118 return (0); 119 120 default: 121 db_printf("db_var_curcpu: unknown operation\n"); 122 return (0); 123 } 124 } 125 126 #ifdef VIMAGE 127 /* 128 * Validate the virtual network pointer used to interpret per-vnet global 129 * variable expansion. Right now we don't do much here, really we should 130 * walk the global vnet list to check it's an OK pointer. 131 */ 132 int 133 db_var_db_vnet(struct db_variable *vp, db_expr_t *valuep, int op) 134 { 135 136 switch (op) { 137 case DB_VAR_GET: 138 *valuep = (db_expr_t)db_vnet; 139 return (1); 140 141 case DB_VAR_SET: 142 db_vnet = *(void **)valuep; 143 return (1); 144 145 default: 146 db_printf("db_var_db_vnet: unknown operation\n"); 147 return (0); 148 } 149 } 150 151 /* 152 * Read-only variable reporting the current vnet, which is what we use when 153 * db_vnet is set to NULL. 154 */ 155 int 156 db_var_curvnet(struct db_variable *vp, db_expr_t *valuep, int op) 157 { 158 159 switch (op) { 160 case DB_VAR_GET: 161 *valuep = (db_expr_t)curvnet; 162 return (1); 163 164 case DB_VAR_SET: 165 db_printf("Read-only variable.\n"); 166 return (0); 167 168 default: 169 db_printf("db_var_curvnet: unknown operation\n"); 170 return (0); 171 } 172 } 173 #endif 174 175 /* 176 * Add symbol table, with given name, to list of symbol tables. 177 */ 178 void 179 db_add_symbol_table(char *start, char *end, char *name, char *ref) 180 { 181 if (db_nsymtab >= MAXNOSYMTABS) { 182 printf ("No slots left for %s symbol table", name); 183 panic ("db_sym.c: db_add_symbol_table"); 184 } 185 186 db_symtabs[db_nsymtab].start = start; 187 db_symtabs[db_nsymtab].end = end; 188 db_symtabs[db_nsymtab].name = name; 189 db_symtabs[db_nsymtab].private = ref; 190 db_nsymtab++; 191 } 192 193 /* 194 * db_qualify("vm_map", "ux") returns "unix:vm_map". 195 * 196 * Note: return value points to static data whose content is 197 * overwritten by each call... but in practice this seems okay. 198 */ 199 static char * 200 db_qualify(c_db_sym_t sym, 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 bool 211 db_eqname(const char *src, const char *dst, int c) 212 { 213 if (!strcmp(src, dst)) 214 return (true); 215 if (src[0] == c) 216 return (!strcmp(src+1,dst)); 217 return (false); 218 } 219 220 bool 221 db_value_of_name(const char *name, db_expr_t *valuep) 222 { 223 c_db_sym_t sym; 224 225 sym = db_lookup(name); 226 if (sym == C_DB_SYM_NULL) 227 return (false); 228 db_symbol_values(sym, &name, valuep); 229 return (true); 230 } 231 232 bool 233 db_value_of_name_pcpu(const char *name, db_expr_t *valuep) 234 { 235 static char tmp[256]; 236 db_expr_t value; 237 c_db_sym_t sym; 238 int cpu; 239 240 if (db_cpu != -1) 241 cpu = db_cpu; 242 else 243 cpu = curcpu; 244 snprintf(tmp, sizeof(tmp), "pcpu_entry_%s", name); 245 sym = db_lookup(tmp); 246 if (sym == C_DB_SYM_NULL) 247 return (false); 248 db_symbol_values(sym, &name, &value); 249 if (value < DPCPU_START || value >= DPCPU_STOP) 250 return (false); 251 *valuep = (db_expr_t)((uintptr_t)value + dpcpu_off[cpu]); 252 return (true); 253 } 254 255 bool 256 db_value_of_name_vnet(const char *name, db_expr_t *valuep) 257 { 258 #ifdef VIMAGE 259 static char tmp[256]; 260 db_expr_t value; 261 c_db_sym_t sym; 262 struct vnet *vnet; 263 264 if (db_vnet != NULL) 265 vnet = db_vnet; 266 else 267 vnet = curvnet; 268 snprintf(tmp, sizeof(tmp), "vnet_entry_%s", name); 269 sym = db_lookup(tmp); 270 if (sym == C_DB_SYM_NULL) 271 return (false); 272 db_symbol_values(sym, &name, &value); 273 if (value < VNET_START || value >= VNET_STOP) 274 return (false); 275 *valuep = (db_expr_t)((uintptr_t)value + vnet->vnet_data_base); 276 return (true); 277 #else 278 return (false); 279 #endif 280 } 281 282 /* 283 * Lookup a symbol. 284 * If the symbol has a qualifier (e.g., ux:vm_map), 285 * then only the specified symbol table will be searched; 286 * otherwise, all symbol tables will be searched. 287 */ 288 static c_db_sym_t 289 db_lookup(const char *symstr) 290 { 291 c_db_sym_t sp; 292 int i; 293 int symtab_start = 0; 294 int symtab_end = db_nsymtab; 295 const char *cp; 296 297 /* 298 * Look for, remove, and remember any symbol table specifier. 299 */ 300 for (cp = symstr; *cp; cp++) { 301 if (*cp == ':') { 302 for (i = 0; i < db_nsymtab; i++) { 303 int n = strlen(db_symtabs[i].name); 304 305 if ( 306 n == (cp - symstr) && 307 strncmp(symstr, db_symtabs[i].name, n) == 0 308 ) { 309 symtab_start = i; 310 symtab_end = i + 1; 311 break; 312 } 313 } 314 if (i == db_nsymtab) { 315 db_error("invalid symbol table name"); 316 } 317 symstr = cp+1; 318 } 319 } 320 321 /* 322 * Look in the specified set of symbol tables. 323 * Return on first match. 324 */ 325 for (i = symtab_start; i < symtab_end; i++) { 326 sp = X_db_lookup(&db_symtabs[i], symstr); 327 if (sp) { 328 db_last_symtab = &db_symtabs[i]; 329 return sp; 330 } 331 } 332 return 0; 333 } 334 335 /* 336 * If true, check across symbol tables for multiple occurrences 337 * of a name. Might slow things down quite a bit. 338 */ 339 static volatile bool db_qualify_ambiguous_names = false; 340 341 /* 342 * Does this symbol name appear in more than one symbol table? 343 * Used by db_symbol_values to decide whether to qualify a symbol. 344 */ 345 static bool 346 db_symbol_is_ambiguous(c_db_sym_t sym) 347 { 348 const char *sym_name; 349 int i; 350 bool found_once = false; 351 352 if (!db_qualify_ambiguous_names) 353 return (false); 354 355 db_symbol_values(sym, &sym_name, 0); 356 for (i = 0; i < db_nsymtab; i++) { 357 if (X_db_lookup(&db_symtabs[i], sym_name)) { 358 if (found_once) 359 return (true); 360 found_once = true; 361 } 362 } 363 return (false); 364 } 365 366 /* 367 * Find the closest symbol to val, and return its name 368 * and the difference between val and the symbol found. 369 */ 370 c_db_sym_t 371 db_search_symbol(db_addr_t val, db_strategy_t strategy, db_expr_t *offp) 372 { 373 unsigned int diff; 374 size_t newdiff; 375 int i; 376 c_db_sym_t ret, sym; 377 378 /* 379 * The kernel will never map the first page, so any symbols in that 380 * range cannot refer to addresses. Some third-party assembly files 381 * define internal constants which appear in their symbol table. 382 * Avoiding the lookup for those symbols avoids replacing small offsets 383 * with those symbols during disassembly. 384 */ 385 if (val < PAGE_SIZE) { 386 *offp = 0; 387 return (C_DB_SYM_NULL); 388 } 389 390 ret = C_DB_SYM_NULL; 391 newdiff = diff = val; 392 for (i = 0; i < db_nsymtab; i++) { 393 sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff); 394 if ((uintmax_t)newdiff < (uintmax_t)diff) { 395 db_last_symtab = &db_symtabs[i]; 396 diff = newdiff; 397 ret = sym; 398 } 399 } 400 *offp = diff; 401 return ret; 402 } 403 404 /* 405 * Return name and value of a symbol 406 */ 407 void 408 db_symbol_values(c_db_sym_t sym, const char **namep, db_expr_t *valuep) 409 { 410 db_expr_t value; 411 412 if (sym == DB_SYM_NULL) { 413 *namep = NULL; 414 return; 415 } 416 417 X_db_symbol_values(db_last_symtab, sym, namep, &value); 418 419 if (db_symbol_is_ambiguous(sym)) 420 *namep = db_qualify(sym, db_last_symtab->name); 421 if (valuep) 422 *valuep = value; 423 } 424 425 /* 426 * Print a the closest symbol to value 427 * 428 * After matching the symbol according to the given strategy 429 * we print it in the name+offset format, provided the symbol's 430 * value is close enough (eg smaller than db_maxoff). 431 * We also attempt to print [filename:linenum] when applicable 432 * (eg for procedure names). 433 * 434 * If we could not find a reasonable name+offset representation, 435 * then we just print the value in hex. Small values might get 436 * bogus symbol associations, e.g. 3 might get some absolute 437 * value like _INCLUDE_VERSION or something, therefore we do 438 * not accept symbols whose value is "small" (and use plain hex). 439 */ 440 441 db_expr_t db_maxoff = 0x10000; 442 443 void 444 db_printsym(db_expr_t off, db_strategy_t strategy) 445 { 446 db_expr_t d; 447 char *filename; 448 const char *name; 449 int linenum; 450 c_db_sym_t cursym; 451 452 if (off < 0 && off >= -db_maxoff) { 453 db_printf("%+#lr", (long)off); 454 return; 455 } 456 cursym = db_search_symbol(off, strategy, &d); 457 db_symbol_values(cursym, &name, NULL); 458 if (name == NULL || d >= (db_addr_t)db_maxoff) { 459 db_printf("%#lr", (unsigned long)off); 460 return; 461 } 462 #ifdef DDB_NUMSYM 463 db_printf("%#lr = %s", (unsigned long)off, name); 464 #else 465 db_printf("%s", name); 466 #endif 467 if (d) 468 db_printf("+%+#lr", (long)d); 469 if (strategy == DB_STGY_PROC) { 470 if (db_line_at_pc(cursym, &filename, &linenum, off)) 471 db_printf(" [%s:%d]", filename, linenum); 472 } 473 } 474 475 static bool 476 db_line_at_pc(c_db_sym_t sym, char **filename, int *linenum, db_expr_t pc) 477 { 478 return (X_db_line_at_pc(db_last_symtab, sym, filename, linenum, pc)); 479 } 480 481 bool 482 db_sym_numargs(c_db_sym_t sym, int *nargp, char **argnames) 483 { 484 return (X_db_sym_numargs(db_last_symtab, sym, nargp, argnames)); 485 } 486 487 void 488 db_decode_syscall(struct thread *td, u_int number) 489 { 490 struct proc *p; 491 492 db_printf(" (%u", number); 493 p = (td != NULL) ? td->td_proc : NULL; 494 if (p != NULL) { 495 db_printf(", %s, %s", p->p_sysent->sv_name, 496 syscallname(p, number)); 497 } 498 db_printf(")"); 499 } 500