1 /* $NetBSD: kern_ksyms.c,v 1.59 2010/05/03 09:51:36 darran Exp $ */ 2 3 /*- 4 * Copyright (c) 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software developed for The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 2001, 2003 Anders Magnusson (ragge@ludd.luth.se). 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions 38 * are met: 39 * 1. Redistributions of source code must retain the above copyright 40 * notice, this list of conditions and the following disclaimer. 41 * 2. Redistributions in binary form must reproduce the above copyright 42 * notice, this list of conditions and the following disclaimer in the 43 * documentation and/or other materials provided with the distribution. 44 * 3. The name of the author may not be used to endorse or promote products 45 * derived from this software without specific prior written permission 46 * 47 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 48 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 49 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 50 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 51 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 52 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 53 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 54 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 55 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 56 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 57 */ 58 59 /* 60 * Code to deal with in-kernel symbol table management + /dev/ksyms. 61 * 62 * For each loaded module the symbol table info is kept track of by a 63 * struct, placed in a circular list. The first entry is the kernel 64 * symbol table. 65 */ 66 67 /* 68 * TODO: 69 * 70 * Add support for mmap, poll. 71 */ 72 73 #include <sys/cdefs.h> 74 __KERNEL_RCSID(0, "$NetBSD: kern_ksyms.c,v 1.59 2010/05/03 09:51:36 darran Exp $"); 75 76 #if defined(_KERNEL) && defined(_KERNEL_OPT) 77 #include "opt_ddb.h" 78 #include "opt_ddbparam.h" /* for SYMTAB_SPACE */ 79 #include "opt_dtrace.h" 80 #endif 81 82 #define _KSYMS_PRIVATE 83 84 #include <sys/param.h> 85 #include <sys/queue.h> 86 #include <sys/exec.h> 87 #include <sys/systm.h> 88 #include <sys/conf.h> 89 #include <sys/kmem.h> 90 #include <sys/proc.h> 91 #include <sys/atomic.h> 92 #include <sys/ksyms.h> 93 94 #include <uvm/uvm_extern.h> 95 96 #ifdef DDB 97 #include <ddb/db_output.h> 98 #endif 99 100 #include "ksyms.h" 101 102 #define KSYMS_MAX_ID 65536 103 #ifdef KDTRACE_HOOKS 104 static uint32_t ksyms_nmap[KSYMS_MAX_ID]; /* sorted symbol table map */ 105 #else 106 static uint32_t *ksyms_nmap = NULL; 107 #endif 108 109 static int ksyms_maxlen; 110 static bool ksyms_isopen; 111 static bool ksyms_initted; 112 static struct ksyms_hdr ksyms_hdr; 113 static kmutex_t ksyms_lock; 114 115 void ksymsattach(int); 116 static void ksyms_hdr_init(void *); 117 static void ksyms_sizes_calc(void); 118 119 #ifdef KSYMS_DEBUG 120 #define FOLLOW_CALLS 1 121 #define FOLLOW_MORE_CALLS 2 122 #define FOLLOW_DEVKSYMS 4 123 static int ksyms_debug; 124 #endif 125 126 #ifdef SYMTAB_SPACE 127 #define SYMTAB_FILLER "|This is the symbol table!" 128 129 char db_symtab[SYMTAB_SPACE] = SYMTAB_FILLER; 130 int db_symtabsize = SYMTAB_SPACE; 131 #endif 132 133 int ksyms_symsz; 134 int ksyms_strsz; 135 int ksyms_ctfsz; 136 TAILQ_HEAD(, ksyms_symtab) ksyms_symtabs = 137 TAILQ_HEAD_INITIALIZER(ksyms_symtabs); 138 static struct ksyms_symtab kernel_symtab; 139 140 static int 141 ksyms_verify(void *symstart, void *strstart) 142 { 143 #if defined(DIAGNOSTIC) || defined(DEBUG) 144 if (symstart == NULL) 145 printf("ksyms: Symbol table not found\n"); 146 if (strstart == NULL) 147 printf("ksyms: String table not found\n"); 148 if (symstart == NULL || strstart == NULL) 149 printf("ksyms: Perhaps the kernel is stripped?\n"); 150 #endif 151 if (symstart == NULL || strstart == NULL) 152 return 0; 153 return 1; 154 } 155 156 /* 157 * Finds a certain symbol name in a certain symbol table. 158 */ 159 static Elf_Sym * 160 findsym(const char *name, struct ksyms_symtab *table, int type) 161 { 162 Elf_Sym *sym, *maxsym; 163 int low, mid, high, nglob; 164 char *str, *cmp; 165 166 sym = table->sd_symstart; 167 str = table->sd_strstart - table->sd_usroffset; 168 nglob = table->sd_nglob; 169 low = 0; 170 high = nglob; 171 172 /* 173 * Start with a binary search of all global symbols in this table. 174 * Global symbols must have unique names. 175 */ 176 while (low < high) { 177 mid = (low + high) >> 1; 178 cmp = sym[mid].st_name + str; 179 if (cmp[0] < name[0] || strcmp(cmp, name) < 0) { 180 low = mid + 1; 181 } else { 182 high = mid; 183 } 184 } 185 KASSERT(low == high); 186 if (__predict_true(low < nglob && 187 strcmp(sym[low].st_name + str, name) == 0)) { 188 KASSERT(ELF_ST_BIND(sym[low].st_info) == STB_GLOBAL); 189 return &sym[low]; 190 } 191 192 /* 193 * Perform a linear search of local symbols (rare). Many local 194 * symbols with the same name can exist so are not included in 195 * the binary search. 196 */ 197 if (type != KSYMS_EXTERN) { 198 maxsym = sym + table->sd_symsize / sizeof(Elf_Sym); 199 for (sym += nglob; sym < maxsym; sym++) { 200 if (strcmp(name, sym->st_name + str) == 0) { 201 return sym; 202 } 203 } 204 } 205 return NULL; 206 } 207 208 /* 209 * The "attach" is in reality done in ksyms_init(). 210 */ 211 void 212 ksymsattach(int arg) 213 { 214 215 } 216 217 void 218 ksyms_init(void) 219 { 220 221 #ifdef SYMTAB_SPACE 222 if (!ksyms_initted && 223 strncmp(db_symtab, SYMTAB_FILLER, sizeof(SYMTAB_FILLER))) { 224 ksyms_addsyms_elf(db_symtabsize, db_symtab, 225 db_symtab + db_symtabsize); 226 } 227 #endif 228 229 mutex_init(&ksyms_lock, MUTEX_DEFAULT, IPL_NONE); 230 } 231 232 /* 233 * Add a symbol table. 234 * This is intended for use when the symbol table and its corresponding 235 * string table are easily available. If they are embedded in an ELF 236 * image, use addsymtab_elf() instead. 237 * 238 * name - Symbol's table name. 239 * symstart, symsize - Address and size of the symbol table. 240 * strstart, strsize - Address and size of the string table. 241 * tab - Symbol table to be updated with this information. 242 * newstart - Address to which the symbol table has to be copied during 243 * shrinking. If NULL, it is not moved. 244 */ 245 static const char *addsymtab_strstart; 246 247 static int 248 addsymtab_compar(const void *a, const void *b) 249 { 250 const Elf_Sym *sa, *sb; 251 252 sa = a; 253 sb = b; 254 255 /* 256 * Split the symbol table into two, with globals at the start 257 * and locals at the end. 258 */ 259 if (ELF_ST_BIND(sa->st_info) != ELF_ST_BIND(sb->st_info)) { 260 if (ELF_ST_BIND(sa->st_info) == STB_GLOBAL) { 261 return -1; 262 } 263 if (ELF_ST_BIND(sb->st_info) == STB_GLOBAL) { 264 return 1; 265 } 266 } 267 268 /* Within each band, sort by name. */ 269 return strcmp(sa->st_name + addsymtab_strstart, 270 sb->st_name + addsymtab_strstart); 271 } 272 273 static void 274 addsymtab(const char *name, void *symstart, size_t symsize, 275 void *strstart, size_t strsize, struct ksyms_symtab *tab, 276 void *newstart, void *ctfstart, size_t ctfsize, uint32_t *nmap) 277 { 278 Elf_Sym *sym, *nsym, ts; 279 int i, j, n, nglob; 280 char *str; 281 int nsyms = symsize / sizeof(Elf_Sym); 282 283 /* sanity check for pre-malloc map table used during startup */ 284 if ((nmap == ksyms_nmap) && (nsyms >= KSYMS_MAX_ID)) { 285 printf("kern_ksyms: ERROR %d > %d, increase KSYMS_MAX_ID\n", 286 nsyms, KSYMS_MAX_ID); 287 288 /* truncate for now */ 289 nsyms = KSYMS_MAX_ID-1; 290 } 291 292 tab->sd_symstart = symstart; 293 tab->sd_symsize = symsize; 294 tab->sd_strstart = strstart; 295 tab->sd_strsize = strsize; 296 tab->sd_name = name; 297 tab->sd_minsym = UINTPTR_MAX; 298 tab->sd_maxsym = 0; 299 tab->sd_usroffset = 0; 300 tab->sd_gone = false; 301 #ifdef KDTRACE_HOOKS 302 tab->sd_ctfstart = ctfstart; 303 tab->sd_ctfsize = ctfsize; 304 tab->sd_nmap = nmap; 305 tab->sd_nmapsize = nsyms; 306 #endif 307 #ifdef KSYMS_DEBUG 308 printf("newstart %p sym %p ksyms_symsz %d str %p strsz %d send %p\n", 309 newstart, symstart, symsize, strstart, strsize, 310 tab->sd_strstart + tab->sd_strsize); 311 #endif 312 313 if (nmap) { 314 memset(nmap, 0, nsyms * sizeof(uint32_t)); 315 } 316 317 /* Pack symbol table by removing all file name references. */ 318 sym = tab->sd_symstart; 319 nsym = (Elf_Sym *)newstart; 320 str = tab->sd_strstart; 321 nglob = 0; 322 for (i = n = 0; i < nsyms; i++) { 323 324 /* This breaks CTF mapping, so don't do it when 325 * DTrace is enabled 326 */ 327 #ifndef KDTRACE_HOOKS 328 /* 329 * Remove useless symbols. 330 * Should actually remove all typeless symbols. 331 */ 332 if (sym[i].st_name == 0) 333 continue; /* Skip nameless entries */ 334 if (sym[i].st_shndx == SHN_UNDEF) 335 continue; /* Skip external references */ 336 if (ELF_ST_TYPE(sym[i].st_info) == STT_FILE) 337 continue; /* Skip filenames */ 338 if (ELF_ST_TYPE(sym[i].st_info) == STT_NOTYPE && 339 sym[i].st_value == 0 && 340 strcmp(str + sym[i].st_name, "*ABS*") == 0) 341 continue; /* XXX */ 342 if (ELF_ST_TYPE(sym[i].st_info) == STT_NOTYPE && 343 strcmp(str + sym[i].st_name, "gcc2_compiled.") == 0) 344 continue; /* XXX */ 345 #endif 346 347 /* Save symbol. Set it as an absolute offset */ 348 nsym[n] = sym[i]; 349 350 #ifdef KDTRACE_HOOKS 351 if (nmap != NULL) { 352 /* Save the size, replace it with the symbol id so 353 * the mapping can be done after the cleanup and sort. 354 */ 355 nmap[i] = nsym[n].st_size; 356 nsym[n].st_size = i+1; /* zero is reserved */ 357 } 358 #endif 359 360 nsym[n].st_shndx = SHBSS; 361 j = strlen(nsym[n].st_name + str) + 1; 362 if (j > ksyms_maxlen) 363 ksyms_maxlen = j; 364 nglob += (ELF_ST_BIND(nsym[n].st_info) == STB_GLOBAL); 365 366 /* Compute min and max symbols. */ 367 if (nsym[n].st_value < tab->sd_minsym) { 368 tab->sd_minsym = nsym[n].st_value; 369 } 370 if (nsym[n].st_value > tab->sd_maxsym) { 371 tab->sd_maxsym = nsym[n].st_value; 372 } 373 n++; 374 } 375 376 /* Fill the rest of the record, and sort the symbols. */ 377 tab->sd_symstart = nsym; 378 tab->sd_symsize = n * sizeof(Elf_Sym); 379 tab->sd_nglob = nglob; 380 addsymtab_strstart = str; 381 if (kheapsort(nsym, n, sizeof(Elf_Sym), addsymtab_compar, &ts) != 0) 382 panic("addsymtab"); 383 384 #ifdef KDTRACE_HOOKS 385 /* 386 * Build the mapping from original symbol id to new symbol table. 387 * Deleted symbols will have a zero map, indices will be one based 388 * instead of zero based. 389 * Resulting map is sd_nmap[original_index] = new_index + 1 390 */ 391 if (nmap != NULL) { 392 int new; 393 for (new=0; new<n; new++) { 394 uint32_t orig = nsym[new].st_size - 1; 395 uint32_t size = nmap[orig]; 396 397 nmap[orig] = new + 1; 398 399 /* restore the size */ 400 nsym[new].st_size = size; 401 } 402 } 403 #endif 404 405 /* ksymsread() is unlocked, so membar. */ 406 membar_producer(); 407 TAILQ_INSERT_TAIL(&ksyms_symtabs, tab, sd_queue); 408 ksyms_sizes_calc(); 409 ksyms_initted = true; 410 } 411 412 /* 413 * Setup the kernel symbol table stuff. 414 */ 415 void 416 ksyms_addsyms_elf(int symsize, void *start, void *end) 417 { 418 int i, j; 419 Elf_Shdr *shdr; 420 char *symstart = NULL, *strstart = NULL; 421 size_t strsize = 0; 422 Elf_Ehdr *ehdr; 423 char *ctfstart = NULL; 424 size_t ctfsize = 0; 425 426 if (symsize <= 0) { 427 printf("[ Kernel symbol table missing! ]\n"); 428 return; 429 } 430 431 /* Sanity check */ 432 if (ALIGNED_POINTER(start, long) == 0) { 433 printf("[ Kernel symbol table has bad start address %p ]\n", 434 start); 435 return; 436 } 437 438 ehdr = (Elf_Ehdr *)start; 439 440 /* check if this is a valid ELF header */ 441 /* No reason to verify arch type, the kernel is actually running! */ 442 if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) || 443 ehdr->e_ident[EI_CLASS] != ELFCLASS || 444 ehdr->e_version > 1) { 445 printf("[ Kernel symbol table invalid! ]\n"); 446 return; /* nothing to do */ 447 } 448 449 /* Loaded header will be scratched in addsymtab */ 450 ksyms_hdr_init(start); 451 452 /* Find the symbol table and the corresponding string table. */ 453 shdr = (Elf_Shdr *)((uint8_t *)start + ehdr->e_shoff); 454 for (i = 1; i < ehdr->e_shnum; i++) { 455 if (shdr[i].sh_type != SHT_SYMTAB) 456 continue; 457 if (shdr[i].sh_offset == 0) 458 continue; 459 symstart = (uint8_t *)start + shdr[i].sh_offset; 460 symsize = shdr[i].sh_size; 461 j = shdr[i].sh_link; 462 if (shdr[j].sh_offset == 0) 463 continue; /* Can this happen? */ 464 strstart = (uint8_t *)start + shdr[j].sh_offset; 465 strsize = shdr[j].sh_size; 466 break; 467 } 468 469 #ifdef KDTRACE_HOOKS 470 /* Find the CTF section */ 471 shdr = (Elf_Shdr *)((uint8_t *)start + ehdr->e_shoff); 472 if (ehdr->e_shstrndx != 0) { 473 char *shstr = (uint8_t*)start + 474 shdr[ehdr->e_shstrndx].sh_offset; 475 for (i = 1; i < ehdr->e_shnum; i++) { 476 #ifdef DEBUG 477 printf("ksyms: checking %s\n", &shstr[shdr[i].sh_name]); 478 #endif 479 if (shdr[i].sh_type != SHT_PROGBITS) 480 continue; 481 if (strncmp(".SUNW_ctf", &shstr[shdr[i].sh_name] ,10) != 0) 482 continue; 483 ctfstart = (uint8_t *)start + shdr[i].sh_offset; 484 ctfsize = shdr[i].sh_size; 485 ksyms_ctfsz = ctfsize; 486 #ifdef DEBUG 487 aprint_normal("Found CTF at %p, size 0x%zx\n", 488 ctfstart, ctfsize); 489 #endif 490 break; 491 } 492 #ifdef DEBUG 493 } else { 494 printf("ksyms: e_shstrndx == 0\n"); 495 #endif 496 } 497 #endif 498 499 if (!ksyms_verify(symstart, strstart)) 500 return; 501 502 addsymtab("netbsd", symstart, symsize, strstart, strsize, 503 &kernel_symtab, start, ctfstart, ctfsize, ksyms_nmap); 504 505 #ifdef DEBUG 506 aprint_normal("Loaded initial symtab at %p, strtab at %p, # entries %ld\n", 507 kernel_symtab.sd_symstart, kernel_symtab.sd_strstart, 508 (long)kernel_symtab.sd_symsize/sizeof(Elf_Sym)); 509 #endif 510 } 511 512 /* 513 * Setup the kernel symbol table stuff. 514 * Use this when the address of the symbol and string tables are known; 515 * otherwise use ksyms_init with an ELF image. 516 * We need to pass a minimal ELF header which will later be completed by 517 * ksyms_hdr_init and handed off to userland through /dev/ksyms. We use 518 * a void *rather than a pointer to avoid exposing the Elf_Ehdr type. 519 */ 520 void 521 ksyms_addsyms_explicit(void *ehdr, void *symstart, size_t symsize, 522 void *strstart, size_t strsize) 523 { 524 525 if (!ksyms_verify(symstart, strstart)) 526 return; 527 528 ksyms_hdr_init(ehdr); 529 addsymtab("netbsd", symstart, symsize, strstart, strsize, 530 &kernel_symtab, symstart, NULL, 0, ksyms_nmap); 531 } 532 533 /* 534 * Get the value associated with a symbol. 535 * "mod" is the module name, or null if any module. 536 * "sym" is the symbol name. 537 * "val" is a pointer to the corresponding value, if call succeeded. 538 * Returns 0 if success or ENOENT if no such entry. 539 * 540 * Call with ksyms_lock, unless known that the symbol table can't change. 541 */ 542 int 543 ksyms_getval_unlocked(const char *mod, const char *sym, unsigned long *val, 544 int type) 545 { 546 struct ksyms_symtab *st; 547 Elf_Sym *es; 548 549 #ifdef KSYMS_DEBUG 550 if (ksyms_debug & FOLLOW_CALLS) 551 printf("ksyms_getval_unlocked: mod %s sym %s valp %p\n", 552 mod, sym, val); 553 #endif 554 555 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 556 if (__predict_false(st->sd_gone)) 557 continue; 558 if (mod != NULL && strcmp(st->sd_name, mod)) 559 continue; 560 if ((es = findsym(sym, st, type)) != NULL) { 561 *val = es->st_value; 562 return 0; 563 } 564 } 565 return ENOENT; 566 } 567 568 int 569 ksyms_getval(const char *mod, const char *sym, unsigned long *val, int type) 570 { 571 int rc; 572 573 if (!ksyms_initted) 574 return ENOENT; 575 576 mutex_enter(&ksyms_lock); 577 rc = ksyms_getval_unlocked(mod, sym, val, type); 578 mutex_exit(&ksyms_lock); 579 return rc; 580 } 581 582 struct ksyms_symtab * 583 ksyms_get_mod(const char *mod) 584 { 585 struct ksyms_symtab *st; 586 587 mutex_enter(&ksyms_lock); 588 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 589 if (__predict_false(st->sd_gone)) 590 continue; 591 if (mod != NULL && strcmp(st->sd_name, mod)) 592 continue; 593 break; 594 } 595 mutex_exit(&ksyms_lock); 596 597 return st; 598 } 599 600 601 /* 602 * ksyms_mod_foreach() 603 * 604 * Iterate over the symbol table of the specified module, calling the callback 605 * handler for each symbol. Stop iterating if the handler return is non-zero. 606 * 607 */ 608 609 int 610 ksyms_mod_foreach(const char *mod, ksyms_callback_t callback, void *opaque) 611 { 612 struct ksyms_symtab *st; 613 Elf_Sym *sym, *maxsym; 614 char *str; 615 int symindx; 616 617 if (!ksyms_initted) 618 return ENOENT; 619 620 mutex_enter(&ksyms_lock); 621 622 /* find the module */ 623 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 624 if (__predict_false(st->sd_gone)) 625 continue; 626 if (mod != NULL && strcmp(st->sd_name, mod)) 627 continue; 628 629 sym = st->sd_symstart; 630 str = st->sd_strstart - st->sd_usroffset; 631 632 /* now iterate through the symbols */ 633 maxsym = sym + st->sd_symsize / sizeof(Elf_Sym); 634 for (symindx=0; sym < maxsym; sym++,symindx++) { 635 if (callback(str + sym->st_name, symindx, 636 (void *)sym->st_value, 637 sym->st_size, 638 sym->st_info, 639 opaque) != 0) { 640 break; 641 } 642 } 643 } 644 mutex_exit(&ksyms_lock); 645 646 return 0; 647 } 648 649 /* 650 * Get "mod" and "symbol" associated with an address. 651 * Returns 0 if success or ENOENT if no such entry. 652 * 653 * Call with ksyms_lock, unless known that the symbol table can't change. 654 */ 655 int 656 ksyms_getname(const char **mod, const char **sym, vaddr_t v, int f) 657 { 658 struct ksyms_symtab *st; 659 Elf_Sym *les, *es = NULL; 660 vaddr_t laddr = 0; 661 const char *lmod = NULL; 662 char *stable = NULL; 663 int type, i, sz; 664 665 if (!ksyms_initted) 666 return ENOENT; 667 668 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 669 if (st->sd_gone) 670 continue; 671 if (v < st->sd_minsym || v > st->sd_maxsym) 672 continue; 673 sz = st->sd_symsize/sizeof(Elf_Sym); 674 for (i = 0; i < sz; i++) { 675 les = st->sd_symstart + i; 676 type = ELF_ST_TYPE(les->st_info); 677 678 if ((f & KSYMS_PROC) && (type != STT_FUNC)) 679 continue; 680 681 if (type == STT_NOTYPE) 682 continue; 683 684 if (((f & KSYMS_ANY) == 0) && 685 (type != STT_FUNC) && (type != STT_OBJECT)) 686 continue; 687 688 if ((les->st_value <= v) && (les->st_value > laddr)) { 689 laddr = les->st_value; 690 es = les; 691 lmod = st->sd_name; 692 stable = st->sd_strstart - st->sd_usroffset; 693 } 694 } 695 } 696 if (es == NULL) 697 return ENOENT; 698 if ((f & KSYMS_EXACT) && (v != es->st_value)) 699 return ENOENT; 700 if (mod) 701 *mod = lmod; 702 if (sym) 703 *sym = stable + es->st_name; 704 return 0; 705 } 706 707 /* 708 * Add a symbol table from a loadable module. 709 */ 710 void 711 ksyms_modload(const char *name, void *symstart, vsize_t symsize, 712 char *strstart, vsize_t strsize) 713 { 714 struct ksyms_symtab *st; 715 716 st = kmem_zalloc(sizeof(*st), KM_SLEEP); 717 mutex_enter(&ksyms_lock); 718 addsymtab(name, symstart, symsize, strstart, strsize, st, symstart, 719 NULL, 0, NULL); 720 mutex_exit(&ksyms_lock); 721 } 722 723 /* 724 * Remove a symbol table from a loadable module. 725 */ 726 void 727 ksyms_modunload(const char *name) 728 { 729 struct ksyms_symtab *st; 730 731 mutex_enter(&ksyms_lock); 732 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 733 if (st->sd_gone) 734 continue; 735 if (strcmp(name, st->sd_name) != 0) 736 continue; 737 st->sd_gone = true; 738 if (!ksyms_isopen) { 739 TAILQ_REMOVE(&ksyms_symtabs, st, sd_queue); 740 ksyms_sizes_calc(); 741 kmem_free(st, sizeof(*st)); 742 } 743 break; 744 } 745 mutex_exit(&ksyms_lock); 746 KASSERT(st != NULL); 747 } 748 749 #ifdef DDB 750 /* 751 * Keep sifting stuff here, to avoid export of ksyms internals. 752 * 753 * Systems is expected to be quiescent, so no locking done. 754 */ 755 int 756 ksyms_sift(char *mod, char *sym, int mode) 757 { 758 struct ksyms_symtab *st; 759 char *sb; 760 int i, sz; 761 762 if (!ksyms_initted) 763 return ENOENT; 764 765 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 766 if (st->sd_gone) 767 continue; 768 if (mod && strcmp(mod, st->sd_name)) 769 continue; 770 sb = st->sd_strstart - st->sd_usroffset; 771 772 sz = st->sd_symsize/sizeof(Elf_Sym); 773 for (i = 0; i < sz; i++) { 774 Elf_Sym *les = st->sd_symstart + i; 775 char c; 776 777 if (strstr(sb + les->st_name, sym) == NULL) 778 continue; 779 780 if (mode == 'F') { 781 switch (ELF_ST_TYPE(les->st_info)) { 782 case STT_OBJECT: 783 c = '+'; 784 break; 785 case STT_FUNC: 786 c = '*'; 787 break; 788 case STT_SECTION: 789 c = '&'; 790 break; 791 case STT_FILE: 792 c = '/'; 793 break; 794 default: 795 c = ' '; 796 break; 797 } 798 db_printf("%s%c ", sb + les->st_name, c); 799 } else 800 db_printf("%s ", sb + les->st_name); 801 } 802 } 803 return ENOENT; 804 } 805 #endif /* DDB */ 806 807 /* 808 * In case we exposing the symbol table to the userland using the pseudo- 809 * device /dev/ksyms, it is easier to provide all the tables as one. 810 * However, it means we have to change all the st_name fields for the 811 * symbols so they match the ELF image that the userland will read 812 * through the device. 813 * 814 * The actual (correct) value of st_name is preserved through a global 815 * offset stored in the symbol table structure. 816 * 817 * Call with ksyms_lock held. 818 */ 819 static void 820 ksyms_sizes_calc(void) 821 { 822 struct ksyms_symtab *st; 823 int i, delta; 824 825 ksyms_symsz = ksyms_strsz = 0; 826 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 827 delta = ksyms_strsz - st->sd_usroffset; 828 if (delta != 0) { 829 for (i = 0; i < st->sd_symsize/sizeof(Elf_Sym); i++) 830 st->sd_symstart[i].st_name += delta; 831 st->sd_usroffset = ksyms_strsz; 832 } 833 ksyms_symsz += st->sd_symsize; 834 ksyms_strsz += st->sd_strsize; 835 } 836 } 837 838 static void 839 ksyms_hdr_init(void *hdraddr) 840 { 841 842 /* Copy the loaded elf exec header */ 843 memcpy(&ksyms_hdr.kh_ehdr, hdraddr, sizeof(Elf_Ehdr)); 844 845 /* Set correct program/section header sizes, offsets and numbers */ 846 ksyms_hdr.kh_ehdr.e_phoff = offsetof(struct ksyms_hdr, kh_phdr[0]); 847 ksyms_hdr.kh_ehdr.e_phentsize = sizeof(Elf_Phdr); 848 ksyms_hdr.kh_ehdr.e_phnum = NPRGHDR; 849 ksyms_hdr.kh_ehdr.e_shoff = offsetof(struct ksyms_hdr, kh_shdr[0]); 850 ksyms_hdr.kh_ehdr.e_shentsize = sizeof(Elf_Shdr); 851 ksyms_hdr.kh_ehdr.e_shnum = NSECHDR; 852 ksyms_hdr.kh_ehdr.e_shstrndx = SHSTRTAB; 853 854 /* Text/data - fake */ 855 ksyms_hdr.kh_phdr[0].p_type = PT_LOAD; 856 ksyms_hdr.kh_phdr[0].p_memsz = (unsigned long)-1L; 857 ksyms_hdr.kh_phdr[0].p_flags = PF_R | PF_X | PF_W; 858 859 /* First section is null */ 860 861 /* Second section header; ".symtab" */ 862 ksyms_hdr.kh_shdr[SYMTAB].sh_name = 1; /* Section 3 offset */ 863 ksyms_hdr.kh_shdr[SYMTAB].sh_type = SHT_SYMTAB; 864 ksyms_hdr.kh_shdr[SYMTAB].sh_offset = sizeof(struct ksyms_hdr); 865 /* ksyms_hdr.kh_shdr[SYMTAB].sh_size = filled in at open */ 866 ksyms_hdr.kh_shdr[SYMTAB].sh_link = 2; /* Corresponding strtab */ 867 ksyms_hdr.kh_shdr[SYMTAB].sh_addralign = sizeof(long); 868 ksyms_hdr.kh_shdr[SYMTAB].sh_entsize = sizeof(Elf_Sym); 869 870 /* Third section header; ".strtab" */ 871 ksyms_hdr.kh_shdr[STRTAB].sh_name = 9; /* Section 3 offset */ 872 ksyms_hdr.kh_shdr[STRTAB].sh_type = SHT_STRTAB; 873 /* ksyms_hdr.kh_shdr[STRTAB].sh_offset = filled in at open */ 874 /* ksyms_hdr.kh_shdr[STRTAB].sh_size = filled in at open */ 875 ksyms_hdr.kh_shdr[STRTAB].sh_addralign = sizeof(char); 876 877 /* Fourth section, ".shstrtab" */ 878 ksyms_hdr.kh_shdr[SHSTRTAB].sh_name = 17; /* This section name offset */ 879 ksyms_hdr.kh_shdr[SHSTRTAB].sh_type = SHT_STRTAB; 880 ksyms_hdr.kh_shdr[SHSTRTAB].sh_offset = 881 offsetof(struct ksyms_hdr, kh_strtab); 882 ksyms_hdr.kh_shdr[SHSTRTAB].sh_size = SHSTRSIZ; 883 ksyms_hdr.kh_shdr[SHSTRTAB].sh_addralign = sizeof(char); 884 885 /* Fifth section, ".bss". All symbols reside here. */ 886 ksyms_hdr.kh_shdr[SHBSS].sh_name = 27; /* This section name offset */ 887 ksyms_hdr.kh_shdr[SHBSS].sh_type = SHT_NOBITS; 888 ksyms_hdr.kh_shdr[SHBSS].sh_offset = 0; 889 ksyms_hdr.kh_shdr[SHBSS].sh_size = (unsigned long)-1L; 890 ksyms_hdr.kh_shdr[SHBSS].sh_addralign = PAGE_SIZE; 891 ksyms_hdr.kh_shdr[SHBSS].sh_flags = SHF_ALLOC | SHF_EXECINSTR; 892 893 #ifdef KDTRACE_HOOKS 894 /* Sixth section header; ".SUNW_ctf" */ 895 ksyms_hdr.kh_shdr[SHCTF].sh_name = 32; /* Section 6 offset */ 896 ksyms_hdr.kh_shdr[SHCTF].sh_type = SHT_PROGBITS; 897 /* ksyms_hdr.kh_shdr[SHCTF].sh_offset = filled in at open */ 898 /* ksyms_hdr.kh_shdr[SHCTF].sh_size = filled in at open */ 899 ksyms_hdr.kh_shdr[SHCTF].sh_link = SYMTAB; /* Corresponding symtab */ 900 ksyms_hdr.kh_shdr[SHCTF].sh_addralign = sizeof(char); 901 #endif 902 903 /* Set section names */ 904 strlcpy(&ksyms_hdr.kh_strtab[1], ".symtab", 905 sizeof(ksyms_hdr.kh_strtab) - 1); 906 strlcpy(&ksyms_hdr.kh_strtab[9], ".strtab", 907 sizeof(ksyms_hdr.kh_strtab) - 9); 908 strlcpy(&ksyms_hdr.kh_strtab[17], ".shstrtab", 909 sizeof(ksyms_hdr.kh_strtab) - 17); 910 strlcpy(&ksyms_hdr.kh_strtab[27], ".bss", 911 sizeof(ksyms_hdr.kh_strtab) - 27); 912 #ifdef KDTRACE_HOOKS 913 strlcpy(&ksyms_hdr.kh_strtab[32], ".SUNW_ctf", 914 sizeof(ksyms_hdr.kh_strtab) - 32); 915 #endif 916 } 917 918 static int 919 ksymsopen(dev_t dev, int oflags, int devtype, struct lwp *l) 920 { 921 922 if (minor(dev) != 0 || !ksyms_initted) 923 return ENXIO; 924 925 /* 926 * Create a "snapshot" of the kernel symbol table. Setting 927 * ksyms_isopen will prevent symbol tables from being freed. 928 */ 929 mutex_enter(&ksyms_lock); 930 ksyms_hdr.kh_shdr[SYMTAB].sh_size = ksyms_symsz; 931 ksyms_hdr.kh_shdr[SYMTAB].sh_info = ksyms_symsz / sizeof(Elf_Sym); 932 ksyms_hdr.kh_shdr[STRTAB].sh_offset = ksyms_symsz + 933 ksyms_hdr.kh_shdr[SYMTAB].sh_offset; 934 ksyms_hdr.kh_shdr[STRTAB].sh_size = ksyms_strsz; 935 #ifdef KDTRACE_HOOKS 936 ksyms_hdr.kh_shdr[SHCTF].sh_offset = ksyms_strsz + 937 ksyms_hdr.kh_shdr[STRTAB].sh_offset; 938 ksyms_hdr.kh_shdr[SHCTF].sh_size = ksyms_ctfsz; 939 #endif 940 ksyms_isopen = true; 941 mutex_exit(&ksyms_lock); 942 943 return 0; 944 } 945 946 static int 947 ksymsclose(dev_t dev, int oflags, int devtype, struct lwp *l) 948 { 949 struct ksyms_symtab *st, *next; 950 bool resize; 951 952 /* Discard refernces to symbol tables. */ 953 mutex_enter(&ksyms_lock); 954 ksyms_isopen = false; 955 resize = false; 956 for (st = TAILQ_FIRST(&ksyms_symtabs); st != NULL; st = next) { 957 next = TAILQ_NEXT(st, sd_queue); 958 if (st->sd_gone) { 959 TAILQ_REMOVE(&ksyms_symtabs, st, sd_queue); 960 kmem_free(st, sizeof(*st)); 961 resize = true; 962 } 963 } 964 if (resize) 965 ksyms_sizes_calc(); 966 mutex_exit(&ksyms_lock); 967 968 return 0; 969 } 970 971 static int 972 ksymsread(dev_t dev, struct uio *uio, int ioflag) 973 { 974 struct ksyms_symtab *st; 975 size_t filepos, inpos, off; 976 int error; 977 #ifdef KDTRACE_HOOKS 978 struct ksyms_symtab *cst; 979 #endif 980 981 /* 982 * First: Copy out the ELF header. XXX Lose if ksymsopen() 983 * occurs during read of the header. 984 */ 985 off = uio->uio_offset; 986 if (off < sizeof(struct ksyms_hdr)) { 987 error = uiomove((char *)&ksyms_hdr + off, 988 sizeof(struct ksyms_hdr) - off, uio); 989 if (error != 0) 990 return error; 991 } 992 993 /* 994 * Copy out the symbol table. 995 */ 996 filepos = sizeof(struct ksyms_hdr); 997 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 998 if (uio->uio_resid == 0) 999 return 0; 1000 if (uio->uio_offset <= st->sd_symsize + filepos) { 1001 inpos = uio->uio_offset - filepos; 1002 error = uiomove((char *)st->sd_symstart + inpos, 1003 st->sd_symsize - inpos, uio); 1004 if (error != 0) 1005 return error; 1006 } 1007 filepos += st->sd_symsize; 1008 } 1009 1010 /* 1011 * Copy out the string table 1012 */ 1013 KASSERT(filepos == sizeof(struct ksyms_hdr) + 1014 ksyms_hdr.kh_shdr[SYMTAB].sh_size); 1015 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 1016 if (uio->uio_resid == 0) 1017 return 0; 1018 if (uio->uio_offset <= st->sd_strsize + filepos) { 1019 inpos = uio->uio_offset - filepos; 1020 error = uiomove((char *)st->sd_strstart + inpos, 1021 st->sd_strsize - inpos, uio); 1022 if (error != 0) 1023 return error; 1024 } 1025 filepos += st->sd_strsize; 1026 } 1027 1028 #ifdef KDTRACE_HOOKS 1029 /* 1030 * Copy out the CTF table. 1031 */ 1032 cst = TAILQ_FIRST(&ksyms_symtabs); 1033 if (cst->sd_ctfstart != NULL) { 1034 if (uio->uio_resid == 0) 1035 return 0; 1036 if (uio->uio_offset <= cst->sd_ctfsize + filepos) { 1037 inpos = uio->uio_offset - filepos; 1038 error = uiomove((char *)cst->sd_ctfstart + inpos, 1039 cst->sd_ctfsize - inpos, uio); 1040 if (error != 0) 1041 return error; 1042 } 1043 filepos += cst->sd_ctfsize; 1044 } 1045 #endif 1046 1047 return 0; 1048 } 1049 1050 static int 1051 ksymswrite(dev_t dev, struct uio *uio, int ioflag) 1052 { 1053 1054 return EROFS; 1055 } 1056 1057 static int 1058 ksymsioctl(dev_t dev, u_long cmd, void *data, int fflag, struct lwp *l) 1059 { 1060 struct ksyms_gsymbol *kg = (struct ksyms_gsymbol *)data; 1061 struct ksyms_symtab *st; 1062 Elf_Sym *sym = NULL, copy; 1063 unsigned long val; 1064 int error = 0; 1065 char *str = NULL; 1066 int len; 1067 1068 /* Read ksyms_maxlen only once while not holding the lock. */ 1069 len = ksyms_maxlen; 1070 1071 if (cmd == KIOCGVALUE || cmd == KIOCGSYMBOL) { 1072 str = kmem_alloc(len, KM_SLEEP); 1073 if ((error = copyinstr(kg->kg_name, str, len, NULL)) != 0) { 1074 kmem_free(str, len); 1075 return error; 1076 } 1077 } 1078 1079 switch (cmd) { 1080 case KIOCGVALUE: 1081 /* 1082 * Use the in-kernel symbol lookup code for fast 1083 * retreival of a value. 1084 */ 1085 error = ksyms_getval(NULL, str, &val, KSYMS_EXTERN); 1086 if (error == 0) 1087 error = copyout(&val, kg->kg_value, sizeof(long)); 1088 kmem_free(str, len); 1089 break; 1090 1091 case KIOCGSYMBOL: 1092 /* 1093 * Use the in-kernel symbol lookup code for fast 1094 * retreival of a symbol. 1095 */ 1096 mutex_enter(&ksyms_lock); 1097 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 1098 if (st->sd_gone) 1099 continue; 1100 if ((sym = findsym(str, st, KSYMS_ANY)) == NULL) 1101 continue; 1102 #ifdef notdef 1103 /* Skip if bad binding */ 1104 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL) { 1105 sym = NULL; 1106 continue; 1107 } 1108 #endif 1109 break; 1110 } 1111 if (sym != NULL) { 1112 memcpy(©, sym, sizeof(copy)); 1113 mutex_exit(&ksyms_lock); 1114 error = copyout(©, kg->kg_sym, sizeof(Elf_Sym)); 1115 } else { 1116 mutex_exit(&ksyms_lock); 1117 error = ENOENT; 1118 } 1119 kmem_free(str, len); 1120 break; 1121 1122 case KIOCGSIZE: 1123 /* 1124 * Get total size of symbol table. 1125 */ 1126 mutex_enter(&ksyms_lock); 1127 *(int *)data = ksyms_strsz + ksyms_symsz + 1128 sizeof(struct ksyms_hdr); 1129 mutex_exit(&ksyms_lock); 1130 break; 1131 1132 default: 1133 error = ENOTTY; 1134 break; 1135 } 1136 1137 return error; 1138 } 1139 1140 const struct cdevsw ksyms_cdevsw = { 1141 ksymsopen, ksymsclose, ksymsread, ksymswrite, ksymsioctl, 1142 nullstop, notty, nopoll, nommap, nullkqfilter, D_OTHER | D_MPSAFE 1143 }; 1144