1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright (c) 1996, 2010, Oracle and/or its affiliates. All rights reserved. 24 */ 25 #include <link.h> 26 #include <stdlib.h> 27 #include <unistd.h> 28 #include <sys/types.h> 29 #include <sys/stat.h> 30 #include <sys/regset.h> 31 #include <sys/frame.h> 32 #include <sys/lwp.h> 33 #include <fcntl.h> 34 #include <stdio.h> 35 #include <sys/mman.h> 36 #include <errno.h> 37 #include <signal.h> 38 #include <synch.h> 39 #include <string.h> 40 41 #include "bindings.h" 42 #include "env.h" 43 44 static Elist *bindto_list = NULL; 45 static Elist *bindfrom_list = NULL; 46 47 static bindhead *bhp = NULL; 48 static unsigned int current_map_len = 0; 49 static char *buffer_name; 50 static const sigset_t iset = { ~0U, ~0U, ~0U, ~0U }; 51 static lwp_mutex_t sharedmutex = SHAREDMUTEX; 52 53 /* 54 * This routine was stolen from libelf.so.1 55 */ 56 static unsigned long 57 ehash(const char *name) 58 { 59 unsigned int g, h = 0; 60 const unsigned char *nm = (unsigned char *)name; 61 62 while (*nm != '\0') { 63 h = (h << 4) + *nm++; 64 /* LINTED */ 65 if ((g = (unsigned int)(h & MASK)) != 0) 66 h ^= g >> 24; 67 h &= ~MASK; 68 } 69 return ((unsigned long)h); 70 } 71 72 73 static void 74 output_err_message(const char *msg) 75 { 76 int fd; 77 if ((fd = open("/tmp/bind_err", O_RDWR | O_CREAT, 0666)) == -1) { 78 (void) fprintf(stderr, "bindings.so: unable to open err_log\n"); 79 perror("open"); 80 } 81 (void) lseek(fd, 0, SEEK_END); 82 (void) write(fd, msg, strlen(msg)); 83 (void) close(fd); 84 } 85 86 /* 87 * common mutex locking & unlocking routines for this module. This is to 88 * control the setting of 'lock_held'. 89 */ 90 static void 91 bt_lock(lwp_mutex_t *lock) 92 { 93 if (_lwp_mutex_lock(lock) != 0) { 94 output_err_message("bt_lock failed!!\n"); 95 (void) fprintf(stderr, "bindings.so: unable to obtain lock\n"); 96 perror("_lwp_mutex_lock"); 97 } 98 } 99 100 static void 101 bt_unlock(lwp_mutex_t *lock) 102 { 103 if (_lwp_mutex_unlock(lock) != 0) { 104 output_err_message("bt_unlock failed!!\n"); 105 (void) fprintf(stderr, "bindings.so: unable to unlock lock\n"); 106 perror("_lwp_mutex_unlock"); 107 } 108 } 109 110 111 112 /* 113 * It's always possible that another process sharing our buffer 114 * has caused it to grow. If this is the case we must adjust our 115 * mappings to compensate. 116 */ 117 static void 118 remap_buffer(int fd) 119 { 120 void * new_bhp; 121 if ((new_bhp = mmap(0, bhp->bh_size, PROT_READ | PROT_WRITE, 122 MAP_SHARED, fd, 0)) == MAP_FAILED) { 123 (void) fprintf(stderr, "bindings: remap: mmap failed\n"); 124 perror("mmap"); 125 126 bt_unlock(&bhp->bh_lock); 127 exit(1); 128 } 129 /* 130 * clean up old mapping 131 */ 132 (void) munmap((caddr_t)bhp, current_map_len); 133 bhp = (bindhead *)new_bhp; 134 current_map_len = bhp->bh_size; 135 } 136 137 static void 138 grow_buffer(void) 139 { 140 int fd; 141 if ((fd = open(buffer_name, O_RDWR)) == -1) { 142 (void) fprintf(stderr, 143 "bidings: grow_buffer: open failed: %s\n", buffer_name); 144 perror("open"); 145 bt_unlock(&bhp->bh_lock); 146 exit(1); 147 } 148 if (ftruncate(fd, bhp->bh_size + BLKSIZE) == -1) { 149 (void) fprintf(stderr, "grow_buffer failed\n"); 150 perror("ftruncate"); 151 bt_unlock(&bhp->bh_lock); 152 exit(1); 153 } 154 bhp->bh_size += BLKSIZE; 155 remap_buffer(fd); 156 (void) close(fd); 157 } 158 159 static void 160 get_new_strbuf(void) 161 { 162 bt_lock(&bhp->bh_lock); 163 while (bhp->bh_end + STRBLKSIZE > bhp->bh_size) 164 grow_buffer(); 165 166 bhp->bh_strcur = bhp->bh_end; 167 bhp->bh_end = bhp->bh_strend = bhp->bh_strcur + STRBLKSIZE; 168 bt_unlock(&bhp->bh_lock); 169 } 170 171 static unsigned int 172 save_str(const char *str) 173 { 174 char *sptr; 175 unsigned int bptr; 176 unsigned int slen; 177 178 bt_lock(&bhp->bh_strlock); 179 /* LINTED */ 180 slen = (unsigned int)strlen(str); 181 182 /* 183 * will string fit into our current string buffer? 184 */ 185 if ((slen + 1) > (bhp->bh_strend - bhp->bh_strcur)) 186 get_new_strbuf(); 187 bptr = bhp->bh_strcur; 188 sptr = (char *)bhp + bhp->bh_strcur; 189 bhp->bh_strcur += slen + 1; 190 (void) strncpy(sptr, str, slen); 191 sptr[slen] = '\0'; 192 bt_unlock(&bhp->bh_strlock); 193 return (bptr); 194 } 195 196 197 static unsigned int 198 get_new_entry(void) 199 { 200 unsigned int new_ent; 201 bt_lock(&bhp->bh_lock); 202 while ((sizeof (binding_entry) + bhp->bh_end) > bhp->bh_size) 203 grow_buffer(); 204 new_ent = bhp->bh_end; 205 bhp->bh_end += sizeof (binding_entry); 206 bt_unlock(&bhp->bh_lock); 207 return (new_ent); 208 } 209 210 211 212 static void 213 init_locks(void) 214 { 215 int i; 216 217 (void) memcpy(&bhp->bh_lock, &sharedmutex, sizeof (lwp_mutex_t)); 218 for (i = 0; i < DEFBKTS; i++) 219 (void) memcpy(&bhp->bh_bkts[i].bb_lock, &sharedmutex, 220 sizeof (lwp_mutex_t)); 221 222 (void) memcpy(&bhp->bh_strlock, &sharedmutex, sizeof (lwp_mutex_t)); 223 } 224 225 uint_t 226 la_version(uint_t version) 227 { 228 int fd; 229 sigset_t omask; 230 231 if (version < LAV_CURRENT) { 232 (void) fprintf(stderr, 233 "bindings.so: unexpected link_audit version: %d\n", 234 version); 235 return (0); 236 } 237 238 build_env_list(&bindto_list, (const char *)"BT_BINDTO"); 239 build_env_list(&bindfrom_list, (const char *)"BT_BINDFROM"); 240 241 if ((buffer_name = getenv(FILEENV)) == NULL) 242 buffer_name = DEFFILE; 243 244 (void) sigprocmask(SIG_BLOCK, &iset, &omask); 245 if ((fd = open(buffer_name, O_RDWR | O_CREAT | O_EXCL, 0666)) != -1) { 246 int init_size = sizeof (bindhead) + BLKSIZE; 247 248 if (ftruncate(fd, init_size) == -1) { 249 perror("ftruncate"); 250 return (0); 251 } 252 253 /* LINTED */ 254 if ((bhp = (bindhead *)mmap(0, init_size, 255 PROT_READ | PROT_WRITE, 256 MAP_SHARED, fd, 0)) == MAP_FAILED) { 257 perror("bindings.so: mmap"); 258 return (0); 259 } 260 261 (void) close(fd); 262 263 init_locks(); 264 /* 265 * Lock our structure and then initialize the data 266 */ 267 bt_lock(&bhp->bh_lock); 268 bhp->bh_vers = BINDCURVERS; 269 current_map_len = bhp->bh_size = init_size; 270 bhp->bh_end = sizeof (bindhead); 271 bhp->bh_bktcnt = DEFBKTS; 272 bt_unlock(&bhp->bh_lock); 273 /* 274 * Set up our initial string buffer 275 */ 276 get_new_strbuf(); 277 } else if ((fd = open(buffer_name, O_RDWR)) != -1) { 278 struct stat stbuf; 279 int i; 280 for (i = 0; i < 4; i++) { 281 if (fstat(fd, &stbuf) == -1) { 282 (void) sleep(1); 283 continue; 284 } 285 if (stbuf.st_size < sizeof (bindhead)) { 286 (void) sleep(1); 287 continue; 288 } 289 /* LINTED */ 290 if ((bhp = (bindhead *)mmap(0, stbuf.st_size, 291 PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)) == 292 MAP_FAILED) { 293 (void) fprintf(stderr, 294 "bindings: mmap failed\n"); 295 perror("mmap"); 296 return (0); 297 } 298 299 /* LINTED */ 300 current_map_len = (unsigned int)stbuf.st_size; 301 } 302 if (bhp == NULL) { 303 (void) fprintf(stderr, 304 "bindings: buffer mapping timed out\n"); 305 return (0); 306 } 307 for (i = 0; i < 4; i++) { 308 if (bhp->bh_vers == 0) { 309 (void) sleep(1); 310 continue; 311 } 312 } 313 if (bhp->bh_vers == 0) { 314 (void) fprintf(stderr, 315 "bindings: %s not initialized\n", buffer_name); 316 return (0); 317 } 318 319 bt_lock(&bhp->bh_lock); 320 321 if (bhp->bh_size != current_map_len) 322 remap_buffer(fd); 323 (void) close(fd); 324 } else { 325 (void) fprintf(stderr, "bindings: unable to open %s\n", 326 buffer_name); 327 perror("open"); 328 return (0); 329 } 330 331 (void) sigprocmask(SIG_SETMASK, &omask, NULL); 332 bt_unlock(&bhp->bh_lock); 333 334 return (LAV_CURRENT); 335 } 336 337 /* ARGSUSED 0 */ 338 uint_t 339 la_objopen(Link_map *lmp, Lmid_t lmid, uintptr_t *cookie) 340 { 341 uint_t flags; 342 343 if ((bindto_list == NULL) || 344 (check_list(bindto_list, lmp->l_name))) 345 flags = LA_FLG_BINDTO; 346 else 347 flags = 0; 348 349 if ((bindfrom_list == NULL) || 350 (check_list(bindfrom_list, lmp->l_name))) 351 flags |= LA_FLG_BINDFROM; 352 353 return (flags); 354 } 355 356 357 /* ARGSUSED 1 */ 358 #if defined(__sparcv9) 359 uintptr_t 360 la_sparcv9_pltenter(Elf64_Sym *symp, uint_t symndx, uintptr_t *refcooke, 361 uintptr_t *defcook, La_sparcv9_regs *regset, uint_t *sb_flags, 362 const char *sym_name) 363 #elif defined(__sparc) 364 uintptr_t 365 la_sparcv8_pltenter(Elf32_Sym *symp, uint_t symndx, uintptr_t *refcooke, 366 uintptr_t *defcook, La_sparcv8_regs *regset, uint_t *sb_flags) 367 #elif defined(__amd64) 368 uintptr_t 369 la_amd64_pltenter(Elf64_Sym *symp, uint_t symndx, uintptr_t *refcooke, 370 uintptr_t *defcook, La_amd64_regs *regset, uint_t *sb_flags, 371 const char *sym_name) 372 #elif defined(__i386) 373 uintptr_t 374 la_i86_pltenter(Elf32_Sym *symp, uint_t symndx, uintptr_t *refcooke, 375 uintptr_t *defcook, La_i86_regs *regset, uint_t *sb_flags) 376 #endif 377 { 378 unsigned long bktno; 379 Link_map *dlmp = (Link_map *)*defcook; 380 const char *lib_name; 381 sigset_t omask; 382 #if !defined(_LP64) 383 const char *sym_name = (const char *)symp->st_name; 384 #endif 385 386 387 lib_name = dlmp->l_name; 388 389 (void) sigprocmask(SIG_BLOCK, &iset, &omask); 390 if (sym_name == NULL) { 391 output_err_message("null symname\n"); 392 return (symp->st_value); 393 } 394 395 bktno = ehash(sym_name) % bhp->bh_bktcnt; 396 397 bt_lock(&bhp->bh_bkts[bktno].bb_lock); 398 399 /* 400 * The buffer has been grown (by another process) and 401 * we need to remap it into memory. 402 */ 403 if (bhp->bh_size != current_map_len) { 404 int fd; 405 if ((fd = open(buffer_name, O_RDWR)) == -1) { 406 (void) fprintf(stderr, 407 "bidings: plt_enter: open failed: %s\n", 408 buffer_name); 409 perror("open"); 410 bt_unlock(&bhp->bh_lock); 411 exit(1); 412 } 413 bt_lock(&bhp->bh_lock); 414 remap_buffer(fd); 415 bt_unlock(&bhp->bh_lock); 416 (void) close(fd); 417 } 418 419 if (bhp->bh_bkts[bktno].bb_head == NULL) { 420 binding_entry * bep; 421 unsigned int be_off; 422 unsigned int sym_off; 423 unsigned int lib_off; 424 425 be_off = get_new_entry(); 426 sym_off = save_str(sym_name); 427 lib_off = save_str(lib_name); 428 /* LINTED */ 429 bep = (binding_entry *)((char *)bhp + be_off); 430 bep->be_next = 0; 431 bep->be_sym_name = sym_off; 432 bep->be_lib_name = lib_off; 433 bep->be_count = 1; 434 bhp->bh_bkts[bktno].bb_head = be_off; 435 } else { 436 int strcmp_res; 437 unsigned int prev_off = 0; 438 binding_entry *prev_bep = NULL; 439 unsigned int cur_off; 440 binding_entry *cur_bep; 441 unsigned int lib_off = 0; 442 443 /* 444 * Once we get to the bucket, we do a two tiered 445 * search. First we search for a library match, then 446 * we search for a symbol match. 447 */ 448 cur_off = bhp->bh_bkts[bktno].bb_head; 449 /* LINTED */ 450 cur_bep = (binding_entry *)((char *)bhp + 451 cur_off); 452 while (cur_off && (strcmp_res = strcmp((char *)bhp + 453 cur_bep->be_lib_name, lib_name)) < 0) { 454 prev_off = cur_off; 455 cur_off = cur_bep->be_next; 456 /* LINTED */ 457 cur_bep = (binding_entry *)((char *)bhp + 458 cur_off); 459 } 460 if (cur_off && (strcmp_res == 0)) { 461 /* 462 * This is a small optimization. For 463 * each bucket we will only record a library 464 * name once. Once it has been recorded in 465 * a bucket we will just re-use the same 466 * string. 467 */ 468 lib_off = cur_bep->be_lib_name; 469 while (cur_off && (strcmp_res = strcmp((char *)bhp + 470 cur_bep->be_sym_name, sym_name)) < 0) { 471 prev_off = cur_off; 472 cur_off = cur_bep->be_next; 473 /* LINTED */ 474 cur_bep = (binding_entry *)((char *)bhp + 475 cur_off); 476 } 477 } 478 if (strcmp_res == 0) { 479 /* 480 * We've got a match 481 */ 482 cur_bep->be_count++; 483 } else { 484 unsigned int new_off; 485 binding_entry * new_bep; 486 unsigned int sym_off; 487 488 new_off = get_new_entry(); 489 if (lib_off == 0) 490 lib_off = save_str(lib_name); 491 sym_off = save_str(sym_name); 492 493 /* LINTED */ 494 new_bep = (binding_entry *)((char *)bhp + 495 new_off); 496 new_bep->be_sym_name = sym_off; 497 new_bep->be_lib_name = lib_off; 498 new_bep->be_count = 1; 499 new_bep->be_next = cur_off; 500 if (prev_off) { 501 /* LINTED */ 502 prev_bep = (binding_entry *)((char *)bhp + 503 prev_off); 504 prev_bep->be_next = new_off; 505 } else 506 /* 507 * Insert at head of list. 508 */ 509 bhp->bh_bkts[bktno].bb_head = new_off; 510 511 } 512 } 513 bt_unlock(&bhp->bh_bkts[bktno].bb_lock); 514 (void) sigprocmask(SIG_SETMASK, &omask, NULL); 515 return (symp->st_value); 516 } 517