1 /* $NetBSD: kern_ksyms.c,v 1.57 2010/03/13 16:27:06 christos 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 1.57 2010/03/13 16:27:06 christos 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 tab->sd_ctfstart = ctfstart; 302 tab->sd_ctfsize = ctfsize; 303 tab->sd_nmap = nmap; 304 tab->sd_nmapsize = nsyms; 305 #ifdef KSYMS_DEBUG 306 printf("newstart %p sym %p ksyms_symsz %d str %p strsz %d send %p\n", 307 newstart, symstart, symsize, strstart, strsize, 308 tab->sd_strstart + tab->sd_strsize); 309 #endif 310 311 if (nmap) { 312 memset(nmap, 0, nsyms * sizeof(uint32_t)); 313 } 314 315 /* Pack symbol table by removing all file name references. */ 316 sym = tab->sd_symstart; 317 nsym = (Elf_Sym *)newstart; 318 str = tab->sd_strstart; 319 nglob = 0; 320 for (i = n = 0; i < nsyms; i++) { 321 322 /* This breaks CTF mapping, so don't do it when 323 * DTrace is enabled 324 */ 325 #ifndef KDTRACE_HOOKS 326 /* 327 * Remove useless symbols. 328 * Should actually remove all typeless symbols. 329 */ 330 if (sym[i].st_name == 0) 331 continue; /* Skip nameless entries */ 332 if (sym[i].st_shndx == SHN_UNDEF) 333 continue; /* Skip external references */ 334 if (ELF_ST_TYPE(sym[i].st_info) == STT_FILE) 335 continue; /* Skip filenames */ 336 if (ELF_ST_TYPE(sym[i].st_info) == STT_NOTYPE && 337 sym[i].st_value == 0 && 338 strcmp(str + sym[i].st_name, "*ABS*") == 0) 339 continue; /* XXX */ 340 if (ELF_ST_TYPE(sym[i].st_info) == STT_NOTYPE && 341 strcmp(str + sym[i].st_name, "gcc2_compiled.") == 0) 342 continue; /* XXX */ 343 #endif 344 345 /* Save symbol. Set it as an absolute offset */ 346 nsym[n] = sym[i]; 347 348 if (nmap != NULL) { 349 /* Save the size, replace it with the symbol id so 350 * the mapping can be done after the cleanup and sort. 351 */ 352 nmap[i] = nsym[n].st_size; 353 nsym[n].st_size = i+1; /* zero is reserved */ 354 } 355 356 nsym[n].st_shndx = SHBSS; 357 j = strlen(nsym[n].st_name + str) + 1; 358 if (j > ksyms_maxlen) 359 ksyms_maxlen = j; 360 nglob += (ELF_ST_BIND(nsym[n].st_info) == STB_GLOBAL); 361 362 /* Compute min and max symbols. */ 363 if (nsym[n].st_value < tab->sd_minsym) { 364 tab->sd_minsym = nsym[n].st_value; 365 } 366 if (nsym[n].st_value > tab->sd_maxsym) { 367 tab->sd_maxsym = nsym[n].st_value; 368 } 369 n++; 370 } 371 372 /* Fill the rest of the record, and sort the symbols. */ 373 tab->sd_symstart = nsym; 374 tab->sd_symsize = n * sizeof(Elf_Sym); 375 tab->sd_nglob = nglob; 376 addsymtab_strstart = str; 377 if (kheapsort(nsym, n, sizeof(Elf_Sym), addsymtab_compar, &ts) != 0) 378 panic("addsymtab"); 379 380 /* 381 * Build the mapping from original symbol id to new symbol table. 382 * Deleted symbols will have a zero map, indices will be one based 383 * instead of zero based. 384 * Resulting map is sd_nmap[original_index] = new_index + 1 385 */ 386 if (nmap != NULL) { 387 int new; 388 for (new=0; new<n; new++) { 389 uint32_t orig = nsym[new].st_size - 1; 390 uint32_t size = nmap[orig]; 391 392 nmap[orig] = new + 1; 393 394 /* restore the size */ 395 nsym[new].st_size = size; 396 } 397 } 398 399 /* ksymsread() is unlocked, so membar. */ 400 membar_producer(); 401 TAILQ_INSERT_TAIL(&ksyms_symtabs, tab, sd_queue); 402 ksyms_sizes_calc(); 403 ksyms_initted = true; 404 } 405 406 /* 407 * Setup the kernel symbol table stuff. 408 */ 409 void 410 ksyms_addsyms_elf(int symsize, void *start, void *end) 411 { 412 int i, j; 413 Elf_Shdr *shdr; 414 char *symstart = NULL, *strstart = NULL; 415 size_t strsize = 0; 416 Elf_Ehdr *ehdr; 417 char *ctfstart = NULL; 418 size_t ctfsize = 0; 419 char *shstr = NULL; 420 421 if (symsize <= 0) { 422 printf("[ Kernel symbol table missing! ]\n"); 423 return; 424 } 425 426 /* Sanity check */ 427 if (ALIGNED_POINTER(start, long) == 0) { 428 printf("[ Kernel symbol table has bad start address %p ]\n", 429 start); 430 return; 431 } 432 433 ehdr = (Elf_Ehdr *)start; 434 435 /* check if this is a valid ELF header */ 436 /* No reason to verify arch type, the kernel is actually running! */ 437 if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) || 438 ehdr->e_ident[EI_CLASS] != ELFCLASS || 439 ehdr->e_version > 1) { 440 printf("[ Kernel symbol table invalid! ]\n"); 441 return; /* nothing to do */ 442 } 443 444 /* Loaded header will be scratched in addsymtab */ 445 ksyms_hdr_init(start); 446 447 /* Find the symbol table and the corresponding string table. */ 448 shdr = (Elf_Shdr *)((uint8_t *)start + ehdr->e_shoff); 449 for (i = 1; i < ehdr->e_shnum; i++) { 450 if (shdr[i].sh_type != SHT_SYMTAB) 451 continue; 452 if (shdr[i].sh_offset == 0) 453 continue; 454 symstart = (uint8_t *)start + shdr[i].sh_offset; 455 symsize = shdr[i].sh_size; 456 j = shdr[i].sh_link; 457 if (shdr[j].sh_offset == 0) 458 continue; /* Can this happen? */ 459 strstart = (uint8_t *)start + shdr[j].sh_offset; 460 strsize = shdr[j].sh_size; 461 break; 462 } 463 464 /* Find the CTF section */ 465 shdr = (Elf_Shdr *)((uint8_t *)start + ehdr->e_shoff); 466 if (ehdr->e_shstrndx != 0) { 467 shstr = (uint8_t*)start + shdr[ehdr->e_shstrndx].sh_offset; 468 for (i = 1; i < ehdr->e_shnum; i++) { 469 if (shdr[i].sh_type != SHT_PROGBITS) 470 continue; 471 if (strncmp(".SUNW_ctf", &shstr[shdr[i].sh_name] ,10) != 0) 472 continue; 473 ctfstart = (uint8_t *)start + shdr[i].sh_offset; 474 ctfsize = shdr[i].sh_size; 475 ksyms_ctfsz = ctfsize; 476 #ifdef DEBUG 477 aprint_normal("Found CTF at %p, size 0x%zx\n", 478 ctfstart, ctfsize); 479 #endif 480 break; 481 } 482 } 483 484 if (!ksyms_verify(symstart, strstart)) 485 return; 486 487 addsymtab("netbsd", symstart, symsize, strstart, strsize, 488 &kernel_symtab, start, ctfstart, ctfsize, ksyms_nmap); 489 490 #ifdef DEBUG 491 aprint_normal("Loaded initial symtab at %p, strtab at %p, # entries %ld\n", 492 kernel_symtab.sd_symstart, kernel_symtab.sd_strstart, 493 (long)kernel_symtab.sd_symsize/sizeof(Elf_Sym)); 494 #endif 495 } 496 497 /* 498 * Setup the kernel symbol table stuff. 499 * Use this when the address of the symbol and string tables are known; 500 * otherwise use ksyms_init with an ELF image. 501 * We need to pass a minimal ELF header which will later be completed by 502 * ksyms_hdr_init and handed off to userland through /dev/ksyms. We use 503 * a void *rather than a pointer to avoid exposing the Elf_Ehdr type. 504 */ 505 void 506 ksyms_addsyms_explicit(void *ehdr, void *symstart, size_t symsize, 507 void *strstart, size_t strsize) 508 { 509 510 if (!ksyms_verify(symstart, strstart)) 511 return; 512 513 ksyms_hdr_init(ehdr); 514 addsymtab("netbsd", symstart, symsize, strstart, strsize, 515 &kernel_symtab, symstart, NULL, 0, ksyms_nmap); 516 } 517 518 /* 519 * Get the value associated with a symbol. 520 * "mod" is the module name, or null if any module. 521 * "sym" is the symbol name. 522 * "val" is a pointer to the corresponding value, if call succeeded. 523 * Returns 0 if success or ENOENT if no such entry. 524 * 525 * Call with ksyms_lock, unless known that the symbol table can't change. 526 */ 527 int 528 ksyms_getval_unlocked(const char *mod, const char *sym, unsigned long *val, 529 int type) 530 { 531 struct ksyms_symtab *st; 532 Elf_Sym *es; 533 534 #ifdef KSYMS_DEBUG 535 if (ksyms_debug & FOLLOW_CALLS) 536 printf("ksyms_getval_unlocked: mod %s sym %s valp %p\n", 537 mod, sym, val); 538 #endif 539 540 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 541 if (__predict_false(st->sd_gone)) 542 continue; 543 if (mod != NULL && strcmp(st->sd_name, mod)) 544 continue; 545 if ((es = findsym(sym, st, type)) != NULL) { 546 *val = es->st_value; 547 return 0; 548 } 549 } 550 return ENOENT; 551 } 552 553 int 554 ksyms_getval(const char *mod, const char *sym, unsigned long *val, int type) 555 { 556 int rc; 557 558 if (!ksyms_initted) 559 return ENOENT; 560 561 mutex_enter(&ksyms_lock); 562 rc = ksyms_getval_unlocked(mod, sym, val, type); 563 mutex_exit(&ksyms_lock); 564 return rc; 565 } 566 567 struct ksyms_symtab * 568 ksyms_get_mod(const char *mod) 569 { 570 struct ksyms_symtab *st; 571 572 mutex_enter(&ksyms_lock); 573 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 574 if (__predict_false(st->sd_gone)) 575 continue; 576 if (mod != NULL && strcmp(st->sd_name, mod)) 577 continue; 578 break; 579 } 580 mutex_exit(&ksyms_lock); 581 582 return st; 583 } 584 585 586 /* 587 * ksyms_mod_foreach() 588 * 589 * Iterate over the symbol table of the specified module, calling the callback 590 * handler for each symbol. Stop iterating if the handler return is non-zero. 591 * 592 */ 593 594 int 595 ksyms_mod_foreach(const char *mod, ksyms_callback_t callback, void *opaque) 596 { 597 struct ksyms_symtab *st; 598 Elf_Sym *sym, *maxsym; 599 char *str; 600 int symindx; 601 602 if (!ksyms_initted) 603 return ENOENT; 604 605 mutex_enter(&ksyms_lock); 606 607 /* find the module */ 608 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 609 if (__predict_false(st->sd_gone)) 610 continue; 611 if (mod != NULL && strcmp(st->sd_name, mod)) 612 continue; 613 614 sym = st->sd_symstart; 615 str = st->sd_strstart - st->sd_usroffset; 616 617 /* now iterate through the symbols */ 618 maxsym = sym + st->sd_symsize / sizeof(Elf_Sym); 619 for (symindx=0; sym < maxsym; sym++,symindx++) { 620 if (callback(str + sym->st_name, symindx, 621 (void *)sym->st_value, 622 sym->st_size, 623 sym->st_info, 624 opaque) != 0) { 625 break; 626 } 627 } 628 } 629 mutex_exit(&ksyms_lock); 630 631 return 0; 632 } 633 634 /* 635 * Get "mod" and "symbol" associated with an address. 636 * Returns 0 if success or ENOENT if no such entry. 637 * 638 * Call with ksyms_lock, unless known that the symbol table can't change. 639 */ 640 int 641 ksyms_getname(const char **mod, const char **sym, vaddr_t v, int f) 642 { 643 struct ksyms_symtab *st; 644 Elf_Sym *les, *es = NULL; 645 vaddr_t laddr = 0; 646 const char *lmod = NULL; 647 char *stable = NULL; 648 int type, i, sz; 649 650 if (!ksyms_initted) 651 return ENOENT; 652 653 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 654 if (st->sd_gone) 655 continue; 656 if (v < st->sd_minsym || v > st->sd_maxsym) 657 continue; 658 sz = st->sd_symsize/sizeof(Elf_Sym); 659 for (i = 0; i < sz; i++) { 660 les = st->sd_symstart + i; 661 type = ELF_ST_TYPE(les->st_info); 662 663 if ((f & KSYMS_PROC) && (type != STT_FUNC)) 664 continue; 665 666 if (type == STT_NOTYPE) 667 continue; 668 669 if (((f & KSYMS_ANY) == 0) && 670 (type != STT_FUNC) && (type != STT_OBJECT)) 671 continue; 672 673 if ((les->st_value <= v) && (les->st_value > laddr)) { 674 laddr = les->st_value; 675 es = les; 676 lmod = st->sd_name; 677 stable = st->sd_strstart - st->sd_usroffset; 678 } 679 } 680 } 681 if (es == NULL) 682 return ENOENT; 683 if ((f & KSYMS_EXACT) && (v != es->st_value)) 684 return ENOENT; 685 if (mod) 686 *mod = lmod; 687 if (sym) 688 *sym = stable + es->st_name; 689 return 0; 690 } 691 692 /* 693 * Add a symbol table from a loadable module. 694 */ 695 void 696 ksyms_modload(const char *name, void *symstart, vsize_t symsize, 697 char *strstart, vsize_t strsize) 698 { 699 struct ksyms_symtab *st; 700 701 st = kmem_zalloc(sizeof(*st), KM_SLEEP); 702 mutex_enter(&ksyms_lock); 703 addsymtab(name, symstart, symsize, strstart, strsize, st, symstart, 704 NULL, 0, NULL); 705 mutex_exit(&ksyms_lock); 706 } 707 708 /* 709 * Remove a symbol table from a loadable module. 710 */ 711 void 712 ksyms_modunload(const char *name) 713 { 714 struct ksyms_symtab *st; 715 716 mutex_enter(&ksyms_lock); 717 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 718 if (st->sd_gone) 719 continue; 720 if (strcmp(name, st->sd_name) != 0) 721 continue; 722 st->sd_gone = true; 723 if (!ksyms_isopen) { 724 TAILQ_REMOVE(&ksyms_symtabs, st, sd_queue); 725 ksyms_sizes_calc(); 726 kmem_free(st, sizeof(*st)); 727 } 728 break; 729 } 730 mutex_exit(&ksyms_lock); 731 KASSERT(st != NULL); 732 } 733 734 #ifdef DDB 735 /* 736 * Keep sifting stuff here, to avoid export of ksyms internals. 737 * 738 * Systems is expected to be quiescent, so no locking done. 739 */ 740 int 741 ksyms_sift(char *mod, char *sym, int mode) 742 { 743 struct ksyms_symtab *st; 744 char *sb; 745 int i, sz; 746 747 if (!ksyms_initted) 748 return ENOENT; 749 750 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 751 if (st->sd_gone) 752 continue; 753 if (mod && strcmp(mod, st->sd_name)) 754 continue; 755 sb = st->sd_strstart - st->sd_usroffset; 756 757 sz = st->sd_symsize/sizeof(Elf_Sym); 758 for (i = 0; i < sz; i++) { 759 Elf_Sym *les = st->sd_symstart + i; 760 char c; 761 762 if (strstr(sb + les->st_name, sym) == NULL) 763 continue; 764 765 if (mode == 'F') { 766 switch (ELF_ST_TYPE(les->st_info)) { 767 case STT_OBJECT: 768 c = '+'; 769 break; 770 case STT_FUNC: 771 c = '*'; 772 break; 773 case STT_SECTION: 774 c = '&'; 775 break; 776 case STT_FILE: 777 c = '/'; 778 break; 779 default: 780 c = ' '; 781 break; 782 } 783 db_printf("%s%c ", sb + les->st_name, c); 784 } else 785 db_printf("%s ", sb + les->st_name); 786 } 787 } 788 return ENOENT; 789 } 790 #endif /* DDB */ 791 792 /* 793 * In case we exposing the symbol table to the userland using the pseudo- 794 * device /dev/ksyms, it is easier to provide all the tables as one. 795 * However, it means we have to change all the st_name fields for the 796 * symbols so they match the ELF image that the userland will read 797 * through the device. 798 * 799 * The actual (correct) value of st_name is preserved through a global 800 * offset stored in the symbol table structure. 801 * 802 * Call with ksyms_lock held. 803 */ 804 static void 805 ksyms_sizes_calc(void) 806 { 807 struct ksyms_symtab *st; 808 int i, delta; 809 810 ksyms_symsz = ksyms_strsz = 0; 811 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 812 delta = ksyms_strsz - st->sd_usroffset; 813 if (delta != 0) { 814 for (i = 0; i < st->sd_symsize/sizeof(Elf_Sym); i++) 815 st->sd_symstart[i].st_name += delta; 816 st->sd_usroffset = ksyms_strsz; 817 } 818 ksyms_symsz += st->sd_symsize; 819 ksyms_strsz += st->sd_strsize; 820 } 821 } 822 823 static void 824 ksyms_hdr_init(void *hdraddr) 825 { 826 827 /* Copy the loaded elf exec header */ 828 memcpy(&ksyms_hdr.kh_ehdr, hdraddr, sizeof(Elf_Ehdr)); 829 830 /* Set correct program/section header sizes, offsets and numbers */ 831 ksyms_hdr.kh_ehdr.e_phoff = offsetof(struct ksyms_hdr, kh_phdr[0]); 832 ksyms_hdr.kh_ehdr.e_phentsize = sizeof(Elf_Phdr); 833 ksyms_hdr.kh_ehdr.e_phnum = NPRGHDR; 834 ksyms_hdr.kh_ehdr.e_shoff = offsetof(struct ksyms_hdr, kh_shdr[0]); 835 ksyms_hdr.kh_ehdr.e_shentsize = sizeof(Elf_Shdr); 836 ksyms_hdr.kh_ehdr.e_shnum = NSECHDR; 837 ksyms_hdr.kh_ehdr.e_shstrndx = SHSTRTAB; 838 839 /* Text/data - fake */ 840 ksyms_hdr.kh_phdr[0].p_type = PT_LOAD; 841 ksyms_hdr.kh_phdr[0].p_memsz = (unsigned long)-1L; 842 ksyms_hdr.kh_phdr[0].p_flags = PF_R | PF_X | PF_W; 843 844 /* First section is null */ 845 846 /* Second section header; ".symtab" */ 847 ksyms_hdr.kh_shdr[SYMTAB].sh_name = 1; /* Section 3 offset */ 848 ksyms_hdr.kh_shdr[SYMTAB].sh_type = SHT_SYMTAB; 849 ksyms_hdr.kh_shdr[SYMTAB].sh_offset = sizeof(struct ksyms_hdr); 850 /* ksyms_hdr.kh_shdr[SYMTAB].sh_size = filled in at open */ 851 ksyms_hdr.kh_shdr[SYMTAB].sh_link = 2; /* Corresponding strtab */ 852 ksyms_hdr.kh_shdr[SYMTAB].sh_addralign = sizeof(long); 853 ksyms_hdr.kh_shdr[SYMTAB].sh_entsize = sizeof(Elf_Sym); 854 855 /* Third section header; ".strtab" */ 856 ksyms_hdr.kh_shdr[STRTAB].sh_name = 9; /* Section 3 offset */ 857 ksyms_hdr.kh_shdr[STRTAB].sh_type = SHT_STRTAB; 858 /* ksyms_hdr.kh_shdr[STRTAB].sh_offset = filled in at open */ 859 /* ksyms_hdr.kh_shdr[STRTAB].sh_size = filled in at open */ 860 ksyms_hdr.kh_shdr[STRTAB].sh_addralign = sizeof(char); 861 862 /* Fourth section, ".shstrtab" */ 863 ksyms_hdr.kh_shdr[SHSTRTAB].sh_name = 17; /* This section name offset */ 864 ksyms_hdr.kh_shdr[SHSTRTAB].sh_type = SHT_STRTAB; 865 ksyms_hdr.kh_shdr[SHSTRTAB].sh_offset = 866 offsetof(struct ksyms_hdr, kh_strtab); 867 ksyms_hdr.kh_shdr[SHSTRTAB].sh_size = SHSTRSIZ; 868 ksyms_hdr.kh_shdr[SHSTRTAB].sh_addralign = sizeof(char); 869 870 /* Fifth section, ".bss". All symbols reside here. */ 871 ksyms_hdr.kh_shdr[SHBSS].sh_name = 27; /* This section name offset */ 872 ksyms_hdr.kh_shdr[SHBSS].sh_type = SHT_NOBITS; 873 ksyms_hdr.kh_shdr[SHBSS].sh_offset = 0; 874 ksyms_hdr.kh_shdr[SHBSS].sh_size = (unsigned long)-1L; 875 ksyms_hdr.kh_shdr[SHBSS].sh_addralign = PAGE_SIZE; 876 ksyms_hdr.kh_shdr[SHBSS].sh_flags = SHF_ALLOC | SHF_EXECINSTR; 877 878 /* Sixth section header; ".SUNW_ctf" */ 879 ksyms_hdr.kh_shdr[SHCTF].sh_name = 32; /* Section 6 offset */ 880 ksyms_hdr.kh_shdr[SHCTF].sh_type = SHT_PROGBITS; 881 /* ksyms_hdr.kh_shdr[SHCTF].sh_offset = filled in at open */ 882 /* ksyms_hdr.kh_shdr[SHCTF].sh_size = filled in at open */ 883 ksyms_hdr.kh_shdr[SHCTF].sh_link = SYMTAB; /* Corresponding symtab */ 884 ksyms_hdr.kh_shdr[SHCTF].sh_addralign = sizeof(char); 885 886 /* Set section names */ 887 strlcpy(&ksyms_hdr.kh_strtab[1], ".symtab", 888 sizeof(ksyms_hdr.kh_strtab) - 1); 889 strlcpy(&ksyms_hdr.kh_strtab[9], ".strtab", 890 sizeof(ksyms_hdr.kh_strtab) - 9); 891 strlcpy(&ksyms_hdr.kh_strtab[17], ".shstrtab", 892 sizeof(ksyms_hdr.kh_strtab) - 17); 893 strlcpy(&ksyms_hdr.kh_strtab[27], ".bss", 894 sizeof(ksyms_hdr.kh_strtab) - 27); 895 strlcpy(&ksyms_hdr.kh_strtab[32], ".SUNW_ctf", 896 sizeof(ksyms_hdr.kh_strtab) - 32); 897 } 898 899 static int 900 ksymsopen(dev_t dev, int oflags, int devtype, struct lwp *l) 901 { 902 903 if (minor(dev) != 0 || !ksyms_initted) 904 return ENXIO; 905 906 /* 907 * Create a "snapshot" of the kernel symbol table. Setting 908 * ksyms_isopen will prevent symbol tables from being freed. 909 */ 910 mutex_enter(&ksyms_lock); 911 ksyms_hdr.kh_shdr[SYMTAB].sh_size = ksyms_symsz; 912 ksyms_hdr.kh_shdr[SYMTAB].sh_info = ksyms_symsz / sizeof(Elf_Sym); 913 ksyms_hdr.kh_shdr[STRTAB].sh_offset = ksyms_symsz + 914 ksyms_hdr.kh_shdr[SYMTAB].sh_offset; 915 ksyms_hdr.kh_shdr[STRTAB].sh_size = ksyms_strsz; 916 ksyms_hdr.kh_shdr[SHCTF].sh_offset = ksyms_strsz + 917 ksyms_hdr.kh_shdr[STRTAB].sh_offset; 918 ksyms_hdr.kh_shdr[SHCTF].sh_size = ksyms_ctfsz; 919 ksyms_isopen = true; 920 mutex_exit(&ksyms_lock); 921 922 return 0; 923 } 924 925 static int 926 ksymsclose(dev_t dev, int oflags, int devtype, struct lwp *l) 927 { 928 struct ksyms_symtab *st, *next; 929 bool resize; 930 931 /* Discard refernces to symbol tables. */ 932 mutex_enter(&ksyms_lock); 933 ksyms_isopen = false; 934 resize = false; 935 for (st = TAILQ_FIRST(&ksyms_symtabs); st != NULL; st = next) { 936 next = TAILQ_NEXT(st, sd_queue); 937 if (st->sd_gone) { 938 TAILQ_REMOVE(&ksyms_symtabs, st, sd_queue); 939 kmem_free(st, sizeof(*st)); 940 resize = true; 941 } 942 } 943 if (resize) 944 ksyms_sizes_calc(); 945 mutex_exit(&ksyms_lock); 946 947 return 0; 948 } 949 950 static int 951 ksymsread(dev_t dev, struct uio *uio, int ioflag) 952 { 953 struct ksyms_symtab *st, *cst; 954 size_t filepos, inpos, off; 955 int error; 956 957 /* 958 * First: Copy out the ELF header. XXX Lose if ksymsopen() 959 * occurs during read of the header. 960 */ 961 off = uio->uio_offset; 962 if (off < sizeof(struct ksyms_hdr)) { 963 error = uiomove((char *)&ksyms_hdr + off, 964 sizeof(struct ksyms_hdr) - off, uio); 965 if (error != 0) 966 return error; 967 } 968 969 /* 970 * Copy out the symbol table. 971 */ 972 filepos = sizeof(struct ksyms_hdr); 973 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 974 if (uio->uio_resid == 0) 975 return 0; 976 if (uio->uio_offset <= st->sd_symsize + filepos) { 977 inpos = uio->uio_offset - filepos; 978 error = uiomove((char *)st->sd_symstart + inpos, 979 st->sd_symsize - inpos, uio); 980 if (error != 0) 981 return error; 982 } 983 filepos += st->sd_symsize; 984 } 985 986 /* 987 * Copy out the string table 988 */ 989 KASSERT(filepos == sizeof(struct ksyms_hdr) + 990 ksyms_hdr.kh_shdr[SYMTAB].sh_size); 991 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 992 if (uio->uio_resid == 0) 993 return 0; 994 if (uio->uio_offset <= st->sd_strsize + filepos) { 995 inpos = uio->uio_offset - filepos; 996 error = uiomove((char *)st->sd_strstart + inpos, 997 st->sd_strsize - inpos, uio); 998 if (error != 0) 999 return error; 1000 } 1001 filepos += st->sd_strsize; 1002 } 1003 1004 /* 1005 * Copy out the CTF table. 1006 */ 1007 cst = TAILQ_FIRST(&ksyms_symtabs); 1008 if (cst->sd_ctfstart != NULL) { 1009 if (uio->uio_resid == 0) 1010 return 0; 1011 if (uio->uio_offset <= cst->sd_ctfsize + filepos) { 1012 inpos = uio->uio_offset - filepos; 1013 error = uiomove((char *)cst->sd_ctfstart + inpos, 1014 cst->sd_ctfsize - inpos, uio); 1015 if (error != 0) 1016 return error; 1017 } 1018 filepos += cst->sd_ctfsize; 1019 } 1020 1021 1022 return 0; 1023 } 1024 1025 static int 1026 ksymswrite(dev_t dev, struct uio *uio, int ioflag) 1027 { 1028 1029 return EROFS; 1030 } 1031 1032 static int 1033 ksymsioctl(dev_t dev, u_long cmd, void *data, int fflag, struct lwp *l) 1034 { 1035 struct ksyms_gsymbol *kg = (struct ksyms_gsymbol *)data; 1036 struct ksyms_symtab *st; 1037 Elf_Sym *sym = NULL, copy; 1038 unsigned long val; 1039 int error = 0; 1040 char *str = NULL; 1041 int len; 1042 1043 /* Read ksyms_maxlen only once while not holding the lock. */ 1044 len = ksyms_maxlen; 1045 1046 if (cmd == KIOCGVALUE || cmd == KIOCGSYMBOL) { 1047 str = kmem_alloc(len, KM_SLEEP); 1048 if ((error = copyinstr(kg->kg_name, str, len, NULL)) != 0) { 1049 kmem_free(str, len); 1050 return error; 1051 } 1052 } 1053 1054 switch (cmd) { 1055 case KIOCGVALUE: 1056 /* 1057 * Use the in-kernel symbol lookup code for fast 1058 * retreival of a value. 1059 */ 1060 error = ksyms_getval(NULL, str, &val, KSYMS_EXTERN); 1061 if (error == 0) 1062 error = copyout(&val, kg->kg_value, sizeof(long)); 1063 kmem_free(str, len); 1064 break; 1065 1066 case KIOCGSYMBOL: 1067 /* 1068 * Use the in-kernel symbol lookup code for fast 1069 * retreival of a symbol. 1070 */ 1071 mutex_enter(&ksyms_lock); 1072 TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) { 1073 if (st->sd_gone) 1074 continue; 1075 if ((sym = findsym(str, st, KSYMS_ANY)) == NULL) 1076 continue; 1077 #ifdef notdef 1078 /* Skip if bad binding */ 1079 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL) { 1080 sym = NULL; 1081 continue; 1082 } 1083 #endif 1084 break; 1085 } 1086 if (sym != NULL) { 1087 memcpy(©, sym, sizeof(copy)); 1088 mutex_exit(&ksyms_lock); 1089 error = copyout(©, kg->kg_sym, sizeof(Elf_Sym)); 1090 } else { 1091 mutex_exit(&ksyms_lock); 1092 error = ENOENT; 1093 } 1094 kmem_free(str, len); 1095 break; 1096 1097 case KIOCGSIZE: 1098 /* 1099 * Get total size of symbol table. 1100 */ 1101 mutex_enter(&ksyms_lock); 1102 *(int *)data = ksyms_strsz + ksyms_symsz + 1103 sizeof(struct ksyms_hdr); 1104 mutex_exit(&ksyms_lock); 1105 break; 1106 1107 default: 1108 error = ENOTTY; 1109 break; 1110 } 1111 1112 return error; 1113 } 1114 1115 const struct cdevsw ksyms_cdevsw = { 1116 ksymsopen, ksymsclose, ksymsread, ksymswrite, ksymsioctl, 1117 nullstop, notty, nopoll, nommap, nullkqfilter, D_OTHER | D_MPSAFE 1118 }; 1119