1 /* 2 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include <jni.h> 26 #include <unistd.h> 27 #include <fcntl.h> 28 #include <string.h> 29 #include <stdlib.h> 30 #include <stddef.h> 31 #include <elf.h> 32 #include <link.h> 33 #include "libproc_impl.h" 34 #include "salibelf.h" 35 36 // This file has the libproc implementation to read core files. 37 // For live processes, refer to ps_proc.c. Portions of this is adapted 38 // /modelled after Solaris libproc.so (in particular Pcore.c) 39 40 //---------------------------------------------------------------------- 41 // ps_prochandle cleanup helper functions 42 43 // close all file descriptors 44 static void close_elf_files(struct ps_prochandle* ph) { 45 lib_info* lib = NULL; 46 47 // close core file descriptor 48 if (ph->core->core_fd >= 0) 49 close(ph->core->core_fd); 50 51 // close exec file descriptor 52 if (ph->core->exec_fd >= 0) 53 close(ph->core->exec_fd); 54 55 // close interp file descriptor 56 if (ph->core->interp_fd >= 0) 57 close(ph->core->interp_fd); 58 59 // close class share archive file 60 if (ph->core->classes_jsa_fd >= 0) 61 close(ph->core->classes_jsa_fd); 62 63 // close all library file descriptors 64 lib = ph->libs; 65 while (lib) { 66 int fd = lib->fd; 67 if (fd >= 0 && fd != ph->core->exec_fd) close(fd); 68 lib = lib->next; 69 } 70 } 71 72 // clean all map_info stuff 73 static void destroy_map_info(struct ps_prochandle* ph) { 74 map_info* map = ph->core->maps; 75 while (map) { 76 map_info* next = map->next; 77 free(map); 78 map = next; 79 } 80 81 if (ph->core->map_array) { 82 free(ph->core->map_array); 83 } 84 85 // Part of the class sharing workaround 86 map = ph->core->class_share_maps; 87 while (map) { 88 map_info* next = map->next; 89 free(map); 90 map = next; 91 } 92 } 93 94 // ps_prochandle operations 95 static void core_release(struct ps_prochandle* ph) { 96 if (ph->core) { 97 close_elf_files(ph); 98 destroy_map_info(ph); 99 free(ph->core); 100 } 101 } 102 103 static map_info* allocate_init_map(int fd, off_t offset, uintptr_t vaddr, size_t memsz) { 104 map_info* map; 105 if ( (map = (map_info*) calloc(1, sizeof(map_info))) == NULL) { 106 print_debug("can't allocate memory for map_info\n"); 107 return NULL; 108 } 109 110 // initialize map 111 map->fd = fd; 112 map->offset = offset; 113 map->vaddr = vaddr; 114 map->memsz = memsz; 115 return map; 116 } 117 118 // add map info with given fd, offset, vaddr and memsz 119 static map_info* add_map_info(struct ps_prochandle* ph, int fd, off_t offset, 120 uintptr_t vaddr, size_t memsz) { 121 map_info* map; 122 if ((map = allocate_init_map(fd, offset, vaddr, memsz)) == NULL) { 123 return NULL; 124 } 125 126 // add this to map list 127 map->next = ph->core->maps; 128 ph->core->maps = map; 129 ph->core->num_maps++; 130 131 return map; 132 } 133 134 // Part of the class sharing workaround 135 static map_info* add_class_share_map_info(struct ps_prochandle* ph, off_t offset, 136 uintptr_t vaddr, size_t memsz) { 137 map_info* map; 138 if ((map = allocate_init_map(ph->core->classes_jsa_fd, 139 offset, vaddr, memsz)) == NULL) { 140 return NULL; 141 } 142 143 map->next = ph->core->class_share_maps; 144 ph->core->class_share_maps = map; 145 return map; 146 } 147 148 // Return the map_info for the given virtual address. We keep a sorted 149 // array of pointers in ph->map_array, so we can binary search. 150 static map_info* core_lookup(struct ps_prochandle *ph, uintptr_t addr) 151 { 152 int mid, lo = 0, hi = ph->core->num_maps - 1; 153 map_info *mp; 154 155 while (hi - lo > 1) { 156 mid = (lo + hi) / 2; 157 if (addr >= ph->core->map_array[mid]->vaddr) 158 lo = mid; 159 else 160 hi = mid; 161 } 162 163 if (addr < ph->core->map_array[hi]->vaddr) 164 mp = ph->core->map_array[lo]; 165 else 166 mp = ph->core->map_array[hi]; 167 168 if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) 169 return (mp); 170 171 172 // Part of the class sharing workaround 173 // Unfortunately, we have no way of detecting -Xshare state. 174 // Check out the share maps atlast, if we don't find anywhere. 175 // This is done this way so to avoid reading share pages 176 // ahead of other normal maps. For eg. with -Xshare:off we don't 177 // want to prefer class sharing data to data from core. 178 mp = ph->core->class_share_maps; 179 if (mp) { 180 print_debug("can't locate map_info at 0x%lx, trying class share maps\n", 181 addr); 182 } 183 while (mp) { 184 if (addr >= mp->vaddr && addr < mp->vaddr + mp->memsz) { 185 print_debug("located map_info at 0x%lx from class share maps\n", 186 addr); 187 return (mp); 188 } 189 mp = mp->next; 190 } 191 192 print_debug("can't locate map_info at 0x%lx\n", addr); 193 return (NULL); 194 } 195 196 //--------------------------------------------------------------- 197 // Part of the class sharing workaround: 198 // 199 // With class sharing, pages are mapped from classes[_g].jsa file. 200 // The read-only class sharing pages are mapped as MAP_SHARED, 201 // PROT_READ pages. These pages are not dumped into core dump. 202 // With this workaround, these pages are read from classes[_g].jsa. 203 204 // FIXME: !HACK ALERT! 205 // The format of sharing achive file header is needed to read shared heap 206 // file mappings. For now, I am hard coding portion of FileMapHeader here. 207 // Refer to filemap.hpp. 208 209 // FileMapHeader describes the shared space data in the file to be 210 // mapped. This structure gets written to a file. It is not a class, 211 // so that the compilers don't add any compiler-private data to it. 212 213 // Refer to CompactingPermGenGen::n_regions in compactingPermGenGen.hpp 214 #define NUM_SHARED_MAPS 4 215 216 // Refer to FileMapInfo::_current_version in filemap.hpp 217 #define CURRENT_ARCHIVE_VERSION 1 218 219 struct FileMapHeader { 220 int _magic; // identify file type. 221 int _version; // (from enum, above.) 222 size_t _alignment; // how shared archive should be aligned 223 224 struct space_info { 225 int _file_offset; // sizeof(this) rounded to vm page size 226 char* _base; // copy-on-write base address 227 size_t _capacity; // for validity checking 228 size_t _used; // for setting space top on read 229 230 // 4991491 NOTICE These are C++ bool's in filemap.hpp and must match up with 231 // the C type matching the C++ bool type on any given platform. For 232 // Hotspot on BSD we assume the corresponding C type is char but 233 // licensees on BSD versions may need to adjust the type of these fields. 234 char _read_only; // read only space? 235 char _allow_exec; // executable code in space? 236 237 } _space[NUM_SHARED_MAPS]; // was _space[CompactingPermGenGen::n_regions]; 238 239 // Ignore the rest of the FileMapHeader. We don't need those fields here. 240 }; 241 242 static bool read_jboolean(struct ps_prochandle* ph, uintptr_t addr, jboolean* pvalue) { 243 jboolean i; 244 if (ps_pread(ph, (psaddr_t) addr, &i, sizeof(i)) == PS_OK) { 245 *pvalue = i; 246 return true; 247 } else { 248 return false; 249 } 250 } 251 252 static bool read_pointer(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* pvalue) { 253 uintptr_t uip; 254 if (ps_pread(ph, (psaddr_t) addr, &uip, sizeof(uip)) == PS_OK) { 255 *pvalue = uip; 256 return true; 257 } else { 258 return false; 259 } 260 } 261 262 // used to read strings from debuggee 263 static bool read_string(struct ps_prochandle* ph, uintptr_t addr, char* buf, size_t size) { 264 size_t i = 0; 265 char c = ' '; 266 267 while (c != '\0') { 268 if (ps_pread(ph, (psaddr_t) addr, &c, sizeof(char)) != PS_OK) 269 return false; 270 if (i < size - 1) 271 buf[i] = c; 272 else // smaller buffer 273 return false; 274 i++; addr++; 275 } 276 277 buf[i] = '\0'; 278 return true; 279 } 280 281 #define USE_SHARED_SPACES_SYM "UseSharedSpaces" 282 // mangled name of Arguments::SharedArchivePath 283 #define SHARED_ARCHIVE_PATH_SYM "_ZN9Arguments17SharedArchivePathE" 284 285 static bool init_classsharing_workaround(struct ps_prochandle* ph) { 286 lib_info* lib = ph->libs; 287 while (lib != NULL) { 288 // we are iterating over shared objects from the core dump. look for 289 // libjvm[_g].so. 290 const char *jvm_name = 0; 291 if ((jvm_name = strstr(lib->name, "/libjvm.so")) != 0 || 292 (jvm_name = strstr(lib->name, "/libjvm_g.so")) != 0) { 293 char classes_jsa[PATH_MAX]; 294 struct FileMapHeader header; 295 size_t n = 0; 296 int fd = -1, m = 0; 297 uintptr_t base = 0, useSharedSpacesAddr = 0; 298 uintptr_t sharedArchivePathAddrAddr = 0, sharedArchivePathAddr = 0; 299 jboolean useSharedSpaces = 0; 300 301 memset(classes_jsa, 0, sizeof(classes_jsa)); 302 jvm_name = lib->name; 303 useSharedSpacesAddr = lookup_symbol(ph, jvm_name, USE_SHARED_SPACES_SYM); 304 if (useSharedSpacesAddr == 0) { 305 print_debug("can't lookup 'UseSharedSpaces' flag\n"); 306 return false; 307 } 308 309 // Hotspot vm types are not exported to build this library. So 310 // using equivalent type jboolean to read the value of 311 // UseSharedSpaces which is same as hotspot type "bool". 312 if (read_jboolean(ph, useSharedSpacesAddr, &useSharedSpaces) != true) { 313 print_debug("can't read the value of 'UseSharedSpaces' flag\n"); 314 return false; 315 } 316 317 if ((int)useSharedSpaces == 0) { 318 print_debug("UseSharedSpaces is false, assuming -Xshare:off!\n"); 319 return true; 320 } 321 322 sharedArchivePathAddrAddr = lookup_symbol(ph, jvm_name, SHARED_ARCHIVE_PATH_SYM); 323 if (sharedArchivePathAddrAddr == 0) { 324 print_debug("can't lookup shared archive path symbol\n"); 325 return false; 326 } 327 328 if (read_pointer(ph, sharedArchivePathAddrAddr, &sharedArchivePathAddr) != true) { 329 print_debug("can't read shared archive path pointer\n"); 330 return false; 331 } 332 333 if (read_string(ph, sharedArchivePathAddr, classes_jsa, sizeof(classes_jsa)) != true) { 334 print_debug("can't read shared archive path value\n"); 335 return false; 336 } 337 338 print_debug("looking for %s\n", classes_jsa); 339 // open the class sharing archive file 340 fd = pathmap_open(classes_jsa); 341 if (fd < 0) { 342 print_debug("can't open %s!\n", classes_jsa); 343 ph->core->classes_jsa_fd = -1; 344 return false; 345 } else { 346 print_debug("opened %s\n", classes_jsa); 347 } 348 349 // read FileMapHeader from the file 350 memset(&header, 0, sizeof(struct FileMapHeader)); 351 if ((n = read(fd, &header, sizeof(struct FileMapHeader))) 352 != sizeof(struct FileMapHeader)) { 353 print_debug("can't read shared archive file map header from %s\n", classes_jsa); 354 close(fd); 355 return false; 356 } 357 358 // check file magic 359 if (header._magic != 0xf00baba2) { 360 print_debug("%s has bad shared archive file magic number 0x%x, expecing 0xf00baba2\n", 361 classes_jsa, header._magic); 362 close(fd); 363 return false; 364 } 365 366 // check version 367 if (header._version != CURRENT_ARCHIVE_VERSION) { 368 print_debug("%s has wrong shared archive file version %d, expecting %d\n", 369 classes_jsa, header._version, CURRENT_ARCHIVE_VERSION); 370 close(fd); 371 return false; 372 } 373 374 ph->core->classes_jsa_fd = fd; 375 // add read-only maps from classes[_g].jsa to the list of maps 376 for (m = 0; m < NUM_SHARED_MAPS; m++) { 377 if (header._space[m]._read_only) { 378 base = (uintptr_t) header._space[m]._base; 379 // no need to worry about the fractional pages at-the-end. 380 // possible fractional pages are handled by core_read_data. 381 add_class_share_map_info(ph, (off_t) header._space[m]._file_offset, 382 base, (size_t) header._space[m]._used); 383 print_debug("added a share archive map at 0x%lx\n", base); 384 } 385 } 386 return true; 387 } 388 lib = lib->next; 389 } 390 return true; 391 } 392 393 394 //--------------------------------------------------------------------------- 395 // functions to handle map_info 396 397 // Order mappings based on virtual address. We use this function as the 398 // callback for sorting the array of map_info pointers. 399 static int core_cmp_mapping(const void *lhsp, const void *rhsp) 400 { 401 const map_info *lhs = *((const map_info **)lhsp); 402 const map_info *rhs = *((const map_info **)rhsp); 403 404 if (lhs->vaddr == rhs->vaddr) 405 return (0); 406 407 return (lhs->vaddr < rhs->vaddr ? -1 : 1); 408 } 409 410 // we sort map_info by starting virtual address so that we can do 411 // binary search to read from an address. 412 static bool sort_map_array(struct ps_prochandle* ph) { 413 size_t num_maps = ph->core->num_maps; 414 map_info* map = ph->core->maps; 415 int i = 0; 416 417 // allocate map_array 418 map_info** array; 419 if ( (array = (map_info**) malloc(sizeof(map_info*) * num_maps)) == NULL) { 420 print_debug("can't allocate memory for map array\n"); 421 return false; 422 } 423 424 // add maps to array 425 while (map) { 426 array[i] = map; 427 i++; 428 map = map->next; 429 } 430 431 // sort is called twice. If this is second time, clear map array 432 if (ph->core->map_array) free(ph->core->map_array); 433 ph->core->map_array = array; 434 // sort the map_info array by base virtual address. 435 qsort(ph->core->map_array, ph->core->num_maps, sizeof (map_info*), 436 core_cmp_mapping); 437 438 // print map 439 if (is_debug()) { 440 int j = 0; 441 print_debug("---- sorted virtual address map ----\n"); 442 for (j = 0; j < ph->core->num_maps; j++) { 443 print_debug("base = 0x%lx\tsize = %d\n", ph->core->map_array[j]->vaddr, 444 ph->core->map_array[j]->memsz); 445 } 446 } 447 448 return true; 449 } 450 451 #ifndef MIN 452 #define MIN(x, y) (((x) < (y))? (x): (y)) 453 #endif 454 455 static bool core_read_data(struct ps_prochandle* ph, uintptr_t addr, char *buf, size_t size) { 456 ssize_t resid = size; 457 int page_size=sysconf(_SC_PAGE_SIZE); 458 while (resid != 0) { 459 map_info *mp = core_lookup(ph, addr); 460 uintptr_t mapoff; 461 ssize_t len, rem; 462 off_t off; 463 int fd; 464 465 if (mp == NULL) 466 break; /* No mapping for this address */ 467 468 fd = mp->fd; 469 mapoff = addr - mp->vaddr; 470 len = MIN(resid, mp->memsz - mapoff); 471 off = mp->offset + mapoff; 472 473 if ((len = pread(fd, buf, len, off)) <= 0) 474 break; 475 476 resid -= len; 477 addr += len; 478 buf = (char *)buf + len; 479 480 // mappings always start at page boundary. But, may end in fractional 481 // page. fill zeros for possible fractional page at the end of a mapping. 482 rem = mp->memsz % page_size; 483 if (rem > 0) { 484 rem = page_size - rem; 485 len = MIN(resid, rem); 486 resid -= len; 487 addr += len; 488 // we are not assuming 'buf' to be zero initialized. 489 memset(buf, 0, len); 490 buf += len; 491 } 492 } 493 494 if (resid) { 495 print_debug("core read failed for %d byte(s) @ 0x%lx (%d more bytes)\n", 496 size, addr, resid); 497 return false; 498 } else { 499 return true; 500 } 501 } 502 503 // null implementation for write 504 static bool core_write_data(struct ps_prochandle* ph, 505 uintptr_t addr, const char *buf , size_t size) { 506 return false; 507 } 508 509 static bool core_get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, 510 struct reg* regs) { 511 // for core we have cached the lwp regs from NOTE section 512 thread_info* thr = ph->threads; 513 while (thr) { 514 if (thr->lwp_id == lwp_id) { 515 memcpy(regs, &thr->regs, sizeof(struct reg)); 516 return true; 517 } 518 thr = thr->next; 519 } 520 return false; 521 } 522 523 static bool core_get_lwp_info(struct ps_prochandle *ph, lwpid_t lwp_id, void *linfo) { 524 print_debug("core_get_lwp_info not implemented\n"); 525 return false; 526 } 527 528 static ps_prochandle_ops core_ops = { 529 .release= core_release, 530 .p_pread= core_read_data, 531 .p_pwrite= core_write_data, 532 .get_lwp_regs= core_get_lwp_regs, 533 .get_lwp_info= core_get_lwp_info 534 }; 535 536 // read regs and create thread from NT_PRSTATUS entries from core file 537 static bool core_handle_prstatus(struct ps_prochandle* ph, const char* buf, size_t nbytes) { 538 // we have to read prstatus_t from buf 539 // assert(nbytes == sizeof(prstaus_t), "size mismatch on prstatus_t"); 540 prstatus_t* prstat = (prstatus_t*) buf; 541 thread_info* newthr; 542 print_debug("got integer regset for lwp %d\n", prstat->pr_pid); 543 // we set pthread_t to -1 for core dump 544 if((newthr = add_thread_info(ph, (pthread_t) -1, prstat->pr_pid)) == NULL) 545 return false; 546 547 // copy regs 548 memcpy(&newthr->regs, &prstat->pr_reg, sizeof(struct reg)); 549 550 if (is_debug()) { 551 print_debug("integer regset\n"); 552 #ifdef i386 553 // print the regset 554 print_debug("\teax = 0x%x\n", newthr->regs.r_eax); 555 print_debug("\tebx = 0x%x\n", newthr->regs.r_ebx); 556 print_debug("\tecx = 0x%x\n", newthr->regs.r_ecx); 557 print_debug("\tedx = 0x%x\n", newthr->regs.r_edx); 558 print_debug("\tesp = 0x%x\n", newthr->regs.r_esp); 559 print_debug("\tebp = 0x%x\n", newthr->regs.r_ebp); 560 print_debug("\tesi = 0x%x\n", newthr->regs.r_esi); 561 print_debug("\tedi = 0x%x\n", newthr->regs.r_edi); 562 print_debug("\teip = 0x%x\n", newthr->regs.r_eip); 563 #endif 564 565 #if defined(amd64) || defined(x86_64) 566 // print the regset 567 print_debug("\tr15 = 0x%lx\n", newthr->regs.r_r15); 568 print_debug("\tr14 = 0x%lx\n", newthr->regs.r_r14); 569 print_debug("\tr13 = 0x%lx\n", newthr->regs.r_r13); 570 print_debug("\tr12 = 0x%lx\n", newthr->regs.r_r12); 571 print_debug("\trbp = 0x%lx\n", newthr->regs.r_rbp); 572 print_debug("\trbx = 0x%lx\n", newthr->regs.r_rbx); 573 print_debug("\tr11 = 0x%lx\n", newthr->regs.r_r11); 574 print_debug("\tr10 = 0x%lx\n", newthr->regs.r_r10); 575 print_debug("\tr9 = 0x%lx\n", newthr->regs.r_r9); 576 print_debug("\tr8 = 0x%lx\n", newthr->regs.r_r8); 577 print_debug("\trax = 0x%lx\n", newthr->regs.r_rax); 578 print_debug("\trcx = 0x%lx\n", newthr->regs.r_rcx); 579 print_debug("\trdx = 0x%lx\n", newthr->regs.r_rdx); 580 print_debug("\trsi = 0x%lx\n", newthr->regs.r_rsi); 581 print_debug("\trdi = 0x%lx\n", newthr->regs.r_rdi); 582 //print_debug("\torig_rax = 0x%lx\n", newthr->regs.orig_rax); 583 print_debug("\trip = 0x%lx\n", newthr->regs.r_rip); 584 print_debug("\tcs = 0x%lx\n", newthr->regs.r_cs); 585 //print_debug("\teflags = 0x%lx\n", newthr->regs.eflags); 586 print_debug("\trsp = 0x%lx\n", newthr->regs.r_rsp); 587 print_debug("\tss = 0x%lx\n", newthr->regs.r_ss); 588 //print_debug("\tfs_base = 0x%lx\n", newthr->regs.fs_base); 589 //print_debug("\tgs_base = 0x%lx\n", newthr->regs.gs_base); 590 //print_debug("\tds = 0x%lx\n", newthr->regs.ds); 591 //print_debug("\tes = 0x%lx\n", newthr->regs.es); 592 //print_debug("\tfs = 0x%lx\n", newthr->regs.fs); 593 //print_debug("\tgs = 0x%lx\n", newthr->regs.gs); 594 #endif 595 } 596 597 return true; 598 } 599 600 #define ROUNDUP(x, y) ((((x)+((y)-1))/(y))*(y)) 601 602 // read NT_PRSTATUS entries from core NOTE segment 603 static bool core_handle_note(struct ps_prochandle* ph, ELF_PHDR* note_phdr) { 604 char* buf = NULL; 605 char* p = NULL; 606 size_t size = note_phdr->p_filesz; 607 608 // we are interested in just prstatus entries. we will ignore the rest. 609 // Advance the seek pointer to the start of the PT_NOTE data 610 if (lseek(ph->core->core_fd, note_phdr->p_offset, SEEK_SET) == (off_t)-1) { 611 print_debug("failed to lseek to PT_NOTE data\n"); 612 return false; 613 } 614 615 // Now process the PT_NOTE structures. Each one is preceded by 616 // an Elf{32/64}_Nhdr structure describing its type and size. 617 if ( (buf = (char*) malloc(size)) == NULL) { 618 print_debug("can't allocate memory for reading core notes\n"); 619 goto err; 620 } 621 622 // read notes into buffer 623 if (read(ph->core->core_fd, buf, size) != size) { 624 print_debug("failed to read notes, core file must have been truncated\n"); 625 goto err; 626 } 627 628 p = buf; 629 while (p < buf + size) { 630 ELF_NHDR* notep = (ELF_NHDR*) p; 631 char* descdata = p + sizeof(ELF_NHDR) + ROUNDUP(notep->n_namesz, 4); 632 print_debug("Note header with n_type = %d and n_descsz = %u\n", 633 notep->n_type, notep->n_descsz); 634 635 if (notep->n_type == NT_PRSTATUS) { 636 if (core_handle_prstatus(ph, descdata, notep->n_descsz) != true) 637 return false; 638 } 639 p = descdata + ROUNDUP(notep->n_descsz, 4); 640 } 641 642 free(buf); 643 return true; 644 645 err: 646 if (buf) free(buf); 647 return false; 648 } 649 650 // read all segments from core file 651 static bool read_core_segments(struct ps_prochandle* ph, ELF_EHDR* core_ehdr) { 652 int i = 0; 653 ELF_PHDR* phbuf = NULL; 654 ELF_PHDR* core_php = NULL; 655 656 if ((phbuf = read_program_header_table(ph->core->core_fd, core_ehdr)) == NULL) 657 return false; 658 659 /* 660 * Now iterate through the program headers in the core file. 661 * We're interested in two types of Phdrs: PT_NOTE (which 662 * contains a set of saved /proc structures), and PT_LOAD (which 663 * represents a memory mapping from the process's address space). 664 * 665 * Difference b/w Solaris PT_NOTE and BSD PT_NOTE: 666 * 667 * In Solaris there are two PT_NOTE segments the first PT_NOTE (if present) 668 * contains /proc structs in the pre-2.6 unstructured /proc format. the last 669 * PT_NOTE has data in new /proc format. 670 * 671 * In Solaris, there is only one pstatus (process status). pstatus contains 672 * integer register set among other stuff. For each LWP, we have one lwpstatus 673 * entry that has integer regset for that LWP. 674 * 675 * Linux threads are actually 'clone'd processes. To support core analysis 676 * of "multithreaded" process, Linux creates more than one pstatus (called 677 * "prstatus") entry in PT_NOTE. Each prstatus entry has integer regset for one 678 * "thread". Please refer to Linux kernel src file 'fs/binfmt_elf.c', in particular 679 * function "elf_core_dump". 680 */ 681 682 for (core_php = phbuf, i = 0; i < core_ehdr->e_phnum; i++) { 683 switch (core_php->p_type) { 684 case PT_NOTE: 685 if (core_handle_note(ph, core_php) != true) goto err; 686 break; 687 688 case PT_LOAD: { 689 if (core_php->p_filesz != 0) { 690 if (add_map_info(ph, ph->core->core_fd, core_php->p_offset, 691 core_php->p_vaddr, core_php->p_filesz) == NULL) goto err; 692 } 693 break; 694 } 695 } 696 697 core_php++; 698 } 699 700 free(phbuf); 701 return true; 702 err: 703 free(phbuf); 704 return false; 705 } 706 707 // read segments of a shared object 708 static bool read_lib_segments(struct ps_prochandle* ph, int lib_fd, ELF_EHDR* lib_ehdr, uintptr_t lib_base) { 709 int i = 0; 710 ELF_PHDR* phbuf; 711 ELF_PHDR* lib_php = NULL; 712 713 if ((phbuf = read_program_header_table(lib_fd, lib_ehdr)) == NULL) 714 return false; 715 716 // we want to process only PT_LOAD segments that are not writable. 717 // i.e., text segments. The read/write/exec (data) segments would 718 // have been already added from core file segments. 719 for (lib_php = phbuf, i = 0; i < lib_ehdr->e_phnum; i++) { 720 if ((lib_php->p_type == PT_LOAD) && !(lib_php->p_flags & PF_W) && (lib_php->p_filesz != 0)) { 721 if (add_map_info(ph, lib_fd, lib_php->p_offset, lib_php->p_vaddr + lib_base, lib_php->p_filesz) == NULL) 722 goto err; 723 } 724 lib_php++; 725 } 726 727 free(phbuf); 728 return true; 729 err: 730 free(phbuf); 731 return false; 732 } 733 734 // process segments from interpreter (ld-elf.so.1) 735 static bool read_interp_segments(struct ps_prochandle* ph) { 736 ELF_EHDR interp_ehdr; 737 738 if (read_elf_header(ph->core->interp_fd, &interp_ehdr) != true) { 739 print_debug("interpreter is not a valid ELF file\n"); 740 return false; 741 } 742 743 if (read_lib_segments(ph, ph->core->interp_fd, &interp_ehdr, ph->core->ld_base_addr) != true) { 744 print_debug("can't read segments of interpreter\n"); 745 return false; 746 } 747 748 return true; 749 } 750 751 // process segments of a a.out 752 static bool read_exec_segments(struct ps_prochandle* ph, ELF_EHDR* exec_ehdr) { 753 int i = 0; 754 ELF_PHDR* phbuf = NULL; 755 ELF_PHDR* exec_php = NULL; 756 757 if ((phbuf = read_program_header_table(ph->core->exec_fd, exec_ehdr)) == NULL) 758 return false; 759 760 for (exec_php = phbuf, i = 0; i < exec_ehdr->e_phnum; i++) { 761 switch (exec_php->p_type) { 762 763 // add mappings for PT_LOAD segments 764 case PT_LOAD: { 765 // add only non-writable segments of non-zero filesz 766 if (!(exec_php->p_flags & PF_W) && exec_php->p_filesz != 0) { 767 if (add_map_info(ph, ph->core->exec_fd, exec_php->p_offset, exec_php->p_vaddr, exec_php->p_filesz) == NULL) goto err; 768 } 769 break; 770 } 771 772 // read the interpreter and it's segments 773 case PT_INTERP: { 774 char interp_name[BUF_SIZE]; 775 776 pread(ph->core->exec_fd, interp_name, MIN(exec_php->p_filesz, BUF_SIZE), exec_php->p_offset); 777 print_debug("ELF interpreter %s\n", interp_name); 778 // read interpreter segments as well 779 if ((ph->core->interp_fd = pathmap_open(interp_name)) < 0) { 780 print_debug("can't open runtime loader\n"); 781 goto err; 782 } 783 break; 784 } 785 786 // from PT_DYNAMIC we want to read address of first link_map addr 787 case PT_DYNAMIC: { 788 ph->core->dynamic_addr = exec_php->p_vaddr; 789 print_debug("address of _DYNAMIC is 0x%lx\n", ph->core->dynamic_addr); 790 break; 791 } 792 793 } // switch 794 exec_php++; 795 } // for 796 797 free(phbuf); 798 return true; 799 err: 800 free(phbuf); 801 return false; 802 } 803 804 805 #define FIRST_LINK_MAP_OFFSET offsetof(struct r_debug, r_map) 806 #define LD_BASE_OFFSET offsetof(struct r_debug, r_ldbase) 807 #define LINK_MAP_ADDR_OFFSET offsetof(struct link_map, l_addr) 808 #define LINK_MAP_NAME_OFFSET offsetof(struct link_map, l_name) 809 #define LINK_MAP_NEXT_OFFSET offsetof(struct link_map, l_next) 810 811 // read shared library info from runtime linker's data structures. 812 // This work is done by librtlb_db in Solaris 813 static bool read_shared_lib_info(struct ps_prochandle* ph) { 814 uintptr_t addr = ph->core->dynamic_addr; 815 uintptr_t debug_base; 816 uintptr_t first_link_map_addr; 817 uintptr_t ld_base_addr; 818 uintptr_t link_map_addr; 819 uintptr_t lib_base_diff; 820 uintptr_t lib_base; 821 uintptr_t lib_name_addr; 822 char lib_name[BUF_SIZE]; 823 ELF_DYN dyn; 824 ELF_EHDR elf_ehdr; 825 int lib_fd; 826 827 // _DYNAMIC has information of the form 828 // [tag] [data] [tag] [data] ..... 829 // Both tag and data are pointer sized. 830 // We look for dynamic info with DT_DEBUG. This has shared object info. 831 // refer to struct r_debug in link.h 832 833 dyn.d_tag = DT_NULL; 834 while (dyn.d_tag != DT_DEBUG) { 835 if (ps_pread(ph, (psaddr_t) addr, &dyn, sizeof(ELF_DYN)) != PS_OK) { 836 print_debug("can't read debug info from _DYNAMIC\n"); 837 return false; 838 } 839 addr += sizeof(ELF_DYN); 840 } 841 842 // we have got Dyn entry with DT_DEBUG 843 debug_base = dyn.d_un.d_ptr; 844 // at debug_base we have struct r_debug. This has first link map in r_map field 845 if (ps_pread(ph, (psaddr_t) debug_base + FIRST_LINK_MAP_OFFSET, 846 &first_link_map_addr, sizeof(uintptr_t)) != PS_OK) { 847 print_debug("can't read first link map address\n"); 848 return false; 849 } 850 851 // read ld_base address from struct r_debug 852 // XXX: There is no r_ldbase member on BSD 853 /* 854 if (ps_pread(ph, (psaddr_t) debug_base + LD_BASE_OFFSET, &ld_base_addr, 855 sizeof(uintptr_t)) != PS_OK) { 856 print_debug("can't read ld base address\n"); 857 return false; 858 } 859 ph->core->ld_base_addr = ld_base_addr; 860 */ 861 ph->core->ld_base_addr = 0; 862 863 print_debug("interpreter base address is 0x%lx\n", ld_base_addr); 864 865 // now read segments from interp (i.e ld-elf.so.1) 866 if (read_interp_segments(ph) != true) 867 return false; 868 869 // after adding interpreter (ld.so) mappings sort again 870 if (sort_map_array(ph) != true) 871 return false; 872 873 print_debug("first link map is at 0x%lx\n", first_link_map_addr); 874 875 link_map_addr = first_link_map_addr; 876 while (link_map_addr != 0) { 877 // read library base address of the .so. Note that even though <sys/link.h> calls 878 // link_map->l_addr as "base address", this is * not * really base virtual 879 // address of the shared object. This is actually the difference b/w the virtual 880 // address mentioned in shared object and the actual virtual base where runtime 881 // linker loaded it. We use "base diff" in read_lib_segments call below. 882 883 if (ps_pread(ph, (psaddr_t) link_map_addr + LINK_MAP_ADDR_OFFSET, 884 &lib_base_diff, sizeof(uintptr_t)) != PS_OK) { 885 print_debug("can't read shared object base address diff\n"); 886 return false; 887 } 888 889 // read address of the name 890 if (ps_pread(ph, (psaddr_t) link_map_addr + LINK_MAP_NAME_OFFSET, 891 &lib_name_addr, sizeof(uintptr_t)) != PS_OK) { 892 print_debug("can't read address of shared object name\n"); 893 return false; 894 } 895 896 // read name of the shared object 897 if (read_string(ph, (uintptr_t) lib_name_addr, lib_name, sizeof(lib_name)) != true) { 898 print_debug("can't read shared object name\n"); 899 return false; 900 } 901 902 if (lib_name[0] != '\0') { 903 // ignore empty lib names 904 lib_fd = pathmap_open(lib_name); 905 906 if (lib_fd < 0) { 907 print_debug("can't open shared object %s\n", lib_name); 908 // continue with other libraries... 909 } else { 910 if (read_elf_header(lib_fd, &elf_ehdr)) { 911 lib_base = lib_base_diff + find_base_address(lib_fd, &elf_ehdr); 912 print_debug("reading library %s @ 0x%lx [ 0x%lx ]\n", 913 lib_name, lib_base, lib_base_diff); 914 // while adding library mappings we need to use "base difference". 915 if (! read_lib_segments(ph, lib_fd, &elf_ehdr, lib_base_diff)) { 916 print_debug("can't read shared object's segments\n"); 917 close(lib_fd); 918 return false; 919 } 920 add_lib_info_fd(ph, lib_name, lib_fd, lib_base); 921 // Map info is added for the library (lib_name) so 922 // we need to re-sort it before calling the p_pdread. 923 if (sort_map_array(ph) != true) 924 return false; 925 } else { 926 print_debug("can't read ELF header for shared object %s\n", lib_name); 927 close(lib_fd); 928 // continue with other libraries... 929 } 930 } 931 } 932 933 // read next link_map address 934 if (ps_pread(ph, (psaddr_t) link_map_addr + LINK_MAP_NEXT_OFFSET, 935 &link_map_addr, sizeof(uintptr_t)) != PS_OK) { 936 print_debug("can't read next link in link_map\n"); 937 return false; 938 } 939 } 940 941 return true; 942 } 943 944 // the one and only one exposed stuff from this file 945 struct ps_prochandle* Pgrab_core(const char* exec_file, const char* core_file) { 946 ELF_EHDR core_ehdr; 947 ELF_EHDR exec_ehdr; 948 949 struct ps_prochandle* ph = (struct ps_prochandle*) calloc(1, sizeof(struct ps_prochandle)); 950 if (ph == NULL) { 951 print_debug("can't allocate ps_prochandle\n"); 952 return NULL; 953 } 954 955 if ((ph->core = (struct core_data*) calloc(1, sizeof(struct core_data))) == NULL) { 956 free(ph); 957 print_debug("can't allocate ps_prochandle\n"); 958 return NULL; 959 } 960 961 // initialize ph 962 ph->ops = &core_ops; 963 ph->core->core_fd = -1; 964 ph->core->exec_fd = -1; 965 ph->core->interp_fd = -1; 966 967 // open the core file 968 if ((ph->core->core_fd = open(core_file, O_RDONLY)) < 0) { 969 print_debug("can't open core file\n"); 970 goto err; 971 } 972 973 // read core file ELF header 974 if (read_elf_header(ph->core->core_fd, &core_ehdr) != true || core_ehdr.e_type != ET_CORE) { 975 print_debug("core file is not a valid ELF ET_CORE file\n"); 976 goto err; 977 } 978 979 if ((ph->core->exec_fd = open(exec_file, O_RDONLY)) < 0) { 980 print_debug("can't open executable file\n"); 981 goto err; 982 } 983 984 if (read_elf_header(ph->core->exec_fd, &exec_ehdr) != true || exec_ehdr.e_type != ET_EXEC) { 985 print_debug("executable file is not a valid ELF ET_EXEC file\n"); 986 goto err; 987 } 988 989 // process core file segments 990 if (read_core_segments(ph, &core_ehdr) != true) 991 goto err; 992 993 // process exec file segments 994 if (read_exec_segments(ph, &exec_ehdr) != true) 995 goto err; 996 997 // exec file is also treated like a shared object for symbol search 998 if (add_lib_info_fd(ph, exec_file, ph->core->exec_fd, 999 (uintptr_t)0 + find_base_address(ph->core->exec_fd, &exec_ehdr)) == NULL) 1000 goto err; 1001 1002 // allocate and sort maps into map_array, we need to do this 1003 // here because read_shared_lib_info needs to read from debuggee 1004 // address space 1005 if (sort_map_array(ph) != true) 1006 goto err; 1007 1008 if (read_shared_lib_info(ph) != true) 1009 goto err; 1010 1011 // sort again because we have added more mappings from shared objects 1012 if (sort_map_array(ph) != true) 1013 goto err; 1014 1015 if (init_classsharing_workaround(ph) != true) 1016 goto err; 1017 1018 return ph; 1019 1020 err: 1021 Prelease(ph); 1022 return NULL; 1023 }