1 /* 2 * This file is part of ltrace. 3 * Copyright (C) 2011,2012,2013,2014 Petr Machata, Red Hat Inc. 4 * Copyright (C) 2010 Joe Damato 5 * Copyright (C) 1998,2009 Juan Cespedes 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License as 9 * published by the Free Software Foundation; either version 2 of the 10 * License, or (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, but 13 * WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 20 * 02110-1301 USA 21 */ 22 23 #include "config.h" 24 25 #include <sys/types.h> 26 #include <assert.h> 27 #include <errno.h> 28 #include <stdio.h> 29 #include <stdlib.h> 30 #include <string.h> 31 32 #include "backend.h" 33 #include "breakpoint.h" 34 #include "debug.h" 35 #include "fetch.h" 36 #include "options.h" 37 #include "proc.h" 38 #include "value_dict.h" 39 40 #ifndef OS_HAVE_PROCESS_DATA 41 int 42 os_process_init(struct process *proc) 43 { 44 return 0; 45 } 46 47 void 48 os_process_destroy(struct process *proc) 49 { 50 } 51 52 int 53 os_process_clone(struct process *retp, struct process *proc) 54 { 55 return 0; 56 } 57 58 int 59 os_process_exec(struct process *proc) 60 { 61 return 0; 62 } 63 #endif 64 65 #ifndef ARCH_HAVE_PROCESS_DATA 66 int 67 arch_process_init(struct process *proc) 68 { 69 return 0; 70 } 71 72 void 73 arch_process_destroy(struct process *proc) 74 { 75 } 76 77 int 78 arch_process_clone(struct process *retp, struct process *proc) 79 { 80 return 0; 81 } 82 83 int 84 arch_process_exec(struct process *proc) 85 { 86 return 0; 87 } 88 #endif 89 90 #ifndef ARCH_HAVE_DYNLINK_DONE 91 void 92 arch_dynlink_done(struct process *proc) 93 { 94 } 95 #endif 96 97 static int add_process(struct process *proc, int was_exec); 98 static void unlist_process(struct process *proc); 99 100 static void 101 destroy_unwind(struct process *proc) 102 { 103 #if defined(HAVE_LIBUNWIND) 104 if (proc->unwind_priv != NULL) 105 _UPT_destroy(proc->unwind_priv); 106 if (proc->unwind_as != NULL) 107 unw_destroy_addr_space(proc->unwind_as); 108 #endif /* defined(HAVE_LIBUNWIND) */ 109 110 #if defined(HAVE_LIBDW) 111 if (proc->dwfl != NULL) 112 dwfl_end(proc->dwfl); 113 #endif /* defined(HAVE_LIBDW) */ 114 } 115 116 static int 117 process_bare_init(struct process *proc, const char *filename, 118 pid_t pid, int was_exec) 119 { 120 if (!was_exec) { 121 memset(proc, 0, sizeof(*proc)); 122 123 proc->filename = strdup(filename); 124 if (proc->filename == NULL) { 125 fail: 126 free(proc->filename); 127 if (proc->breakpoints != NULL) { 128 dict_destroy(proc->breakpoints, 129 NULL, NULL, NULL); 130 free(proc->breakpoints); 131 proc->breakpoints = NULL; 132 } 133 return -1; 134 } 135 } 136 137 /* Add process so that we know who the leader is. */ 138 proc->pid = pid; 139 if (add_process(proc, was_exec) < 0) 140 goto fail; 141 if (proc->leader == NULL) { 142 unlist_and_fail: 143 if (!was_exec) 144 unlist_process(proc); 145 goto fail; 146 } 147 148 if (proc->leader == proc) { 149 proc->breakpoints = malloc(sizeof(*proc->breakpoints)); 150 if (proc->breakpoints == NULL) 151 goto unlist_and_fail; 152 DICT_INIT(proc->breakpoints, 153 arch_addr_t, struct breakpoint *, 154 arch_addr_hash, arch_addr_eq, NULL); 155 } else { 156 proc->breakpoints = NULL; 157 } 158 159 #if defined(HAVE_LIBUNWIND) 160 if (options.bt_depth > 0) { 161 proc->unwind_priv = _UPT_create(pid); 162 proc->unwind_as = unw_create_addr_space(&_UPT_accessors, 0); 163 164 if (proc->unwind_priv == NULL || proc->unwind_as == NULL) { 165 fprintf(stderr, 166 "Couldn't initialize unwinding " 167 "for process %d\n", proc->pid); 168 destroy_unwind(proc); 169 proc->unwind_priv = NULL; 170 proc->unwind_as = NULL; 171 } 172 } 173 #endif /* defined(HAVE_LIBUNWIND) */ 174 175 #if defined(HAVE_LIBDW) 176 proc->dwfl = NULL; /* Initialize for leader only on first library. */ 177 #endif /* defined(HAVE_LIBDW) */ 178 179 return 0; 180 } 181 182 static void 183 process_bare_destroy(struct process *proc, int was_exec) 184 { 185 dict_destroy(proc->breakpoints, NULL, NULL, NULL); 186 free(proc->breakpoints); 187 if (!was_exec) { 188 free(proc->filename); 189 unlist_process(proc); 190 destroy_unwind(proc); 191 } 192 } 193 194 static int 195 process_init_main(struct process *proc) 196 { 197 if (breakpoints_init(proc) < 0) { 198 fprintf(stderr, "failed to init breakpoints %d\n", 199 proc->pid); 200 return -1; 201 } 202 203 return 0; 204 } 205 206 int 207 process_init(struct process *proc, const char *filename, pid_t pid) 208 { 209 if (process_bare_init(proc, filename, pid, 0) < 0) { 210 fail: 211 fprintf(stderr, "failed to initialize process %d: %s\n", 212 pid, strerror(errno)); 213 return -1; 214 } 215 216 if (os_process_init(proc) < 0) { 217 process_bare_destroy(proc, 0); 218 goto fail; 219 } 220 221 if (arch_process_init(proc) < 0) { 222 os_process_destroy(proc); 223 process_bare_destroy(proc, 0); 224 goto fail; 225 } 226 227 if (proc->leader != proc) { 228 proc->e_machine = proc->leader->e_machine; 229 proc->e_class = proc->leader->e_class; 230 get_arch_dep(proc); 231 } else if (process_init_main(proc) < 0) { 232 process_bare_destroy(proc, 0); 233 goto fail; 234 } 235 return 0; 236 } 237 238 static enum callback_status 239 destroy_breakpoint_cb(struct process *proc, struct breakpoint *bp, void *data) 240 { 241 breakpoint_destroy(bp); 242 free(bp); 243 return CBS_CONT; 244 } 245 246 // XXX see comment in handle_event.c 247 void callstack_pop(struct process *proc); 248 249 static void 250 private_process_destroy(struct process *proc, int was_exec) 251 { 252 /* Pop remaining stack elements. */ 253 while (proc->callstack_depth > 0) { 254 /* When this is called just before a process is 255 * destroyed, the breakpoints should either have been 256 * retracted by now, or were killed by exec. In any 257 * case, it's safe to pretend that there are no 258 * breakpoints associated with the stack elements, so 259 * that stack_pop doesn't attempt to destroy them. */ 260 size_t i = proc->callstack_depth - 1; 261 if (!proc->callstack[i].is_syscall) 262 proc->callstack[i].return_addr = 0; 263 264 callstack_pop(proc); 265 } 266 267 if (!was_exec) 268 free(proc->filename); 269 270 /* Libraries and symbols. This is only relevant in 271 * leader. */ 272 struct library *lib; 273 for (lib = proc->libraries; lib != NULL; ) { 274 struct library *next = lib->next; 275 library_destroy(lib); 276 free(lib); 277 lib = next; 278 } 279 proc->libraries = NULL; 280 281 /* Breakpoints. */ 282 if (proc->breakpoints != NULL) { 283 proc_each_breakpoint(proc, NULL, destroy_breakpoint_cb, NULL); 284 dict_destroy(proc->breakpoints, NULL, NULL, NULL); 285 free(proc->breakpoints); 286 proc->breakpoints = NULL; 287 } 288 289 destroy_unwind(proc); 290 } 291 292 void 293 process_destroy(struct process *proc) 294 { 295 arch_process_destroy(proc); 296 os_process_destroy(proc); 297 private_process_destroy(proc, 0); 298 } 299 300 int 301 process_exec(struct process *proc) 302 { 303 /* Call exec handlers first, before we destroy the main 304 * state. */ 305 if (arch_process_exec(proc) < 0 306 || os_process_exec(proc) < 0) 307 return -1; 308 309 private_process_destroy(proc, 1); 310 311 if (process_bare_init(proc, NULL, proc->pid, 1) < 0) 312 return -1; 313 if (process_init_main(proc) < 0) { 314 process_bare_destroy(proc, 1); 315 return -1; 316 } 317 return 0; 318 } 319 320 struct process * 321 open_program(const char *filename, pid_t pid) 322 { 323 assert(pid != 0); 324 struct process *proc = malloc(sizeof(*proc)); 325 if (proc == NULL || process_init(proc, filename, pid) < 0) { 326 free(proc); 327 return NULL; 328 } 329 return proc; 330 } 331 332 struct clone_single_bp_data { 333 struct process *old_proc; 334 struct process *new_proc; 335 }; 336 337 static enum callback_status 338 clone_single_bp(arch_addr_t *key, struct breakpoint **bpp, void *u) 339 { 340 struct breakpoint *bp = *bpp; 341 struct clone_single_bp_data *data = u; 342 343 struct breakpoint *clone = malloc(sizeof(*clone)); 344 if (clone == NULL 345 || breakpoint_clone(clone, data->new_proc, bp) < 0) { 346 fail: 347 free(clone); 348 return CBS_STOP; 349 } 350 if (proc_add_breakpoint(data->new_proc->leader, clone) < 0) { 351 breakpoint_destroy(clone); 352 goto fail; 353 } 354 return CBS_CONT; 355 } 356 357 int 358 process_clone(struct process *retp, struct process *proc, pid_t pid) 359 { 360 if (process_bare_init(retp, proc->filename, pid, 0) < 0) { 361 fail1: 362 fprintf(stderr, "Failed to clone process %d to %d: %s\n", 363 proc->pid, pid, strerror(errno)); 364 return -1; 365 } 366 367 retp->tracesysgood = proc->tracesysgood; 368 retp->e_machine = proc->e_machine; 369 retp->e_class = proc->e_class; 370 371 /* For non-leader processes, that's all we need to do. */ 372 if (retp->leader != retp) 373 return 0; 374 375 /* Clone symbols first so that we can clone and relink 376 * breakpoints. */ 377 struct library *lib; 378 struct library **nlibp = &retp->libraries; 379 for (lib = proc->leader->libraries; lib != NULL; lib = lib->next) { 380 *nlibp = malloc(sizeof(**nlibp)); 381 382 if (*nlibp == NULL 383 || library_clone(*nlibp, lib) < 0) { 384 free(*nlibp); 385 *nlibp = NULL; 386 387 fail2: 388 process_bare_destroy(retp, 0); 389 390 /* Error when cloning. Unroll what was done. */ 391 for (lib = retp->libraries; lib != NULL; ) { 392 struct library *next = lib->next; 393 library_destroy(lib); 394 free(lib); 395 lib = next; 396 } 397 goto fail1; 398 } 399 400 nlibp = &(*nlibp)->next; 401 } 402 403 /* Now clone breakpoints. Symbol relinking is done in 404 * clone_single_bp. */ 405 struct clone_single_bp_data data = { 406 .old_proc = proc, 407 .new_proc = retp, 408 }; 409 if (DICT_EACH(proc->leader->breakpoints, 410 arch_addr_t, struct breakpoint *, NULL, 411 clone_single_bp, &data) != NULL) 412 goto fail2; 413 414 /* And finally the call stack. */ 415 /* XXX clearly the callstack handling should be moved to a 416 * separate module and this whole business extracted to 417 * callstack_clone, or callstack_element_clone. */ 418 memcpy(retp->callstack, proc->callstack, sizeof(retp->callstack)); 419 retp->callstack_depth = proc->callstack_depth; 420 421 size_t i; 422 for (i = 0; i < retp->callstack_depth; ++i) { 423 struct callstack_element *elem = &retp->callstack[i]; 424 struct fetch_context *ctx = elem->fetch_context; 425 if (ctx != NULL) { 426 struct fetch_context *nctx = fetch_arg_clone(retp, ctx); 427 if (nctx == NULL) { 428 size_t j; 429 fail3: 430 for (j = 0; j < i; ++j) { 431 nctx = retp->callstack[j].fetch_context; 432 fetch_arg_done(nctx); 433 elem->fetch_context = NULL; 434 } 435 goto fail2; 436 } 437 elem->fetch_context = nctx; 438 } 439 440 if (elem->arguments != NULL) { 441 struct value_dict *nargs = malloc(sizeof(*nargs)); 442 if (nargs == NULL 443 || val_dict_clone(nargs, elem->arguments) < 0) { 444 size_t j; 445 for (j = 0; j < i; ++j) { 446 nargs = retp->callstack[j].arguments; 447 val_dict_destroy(nargs); 448 free(nargs); 449 elem->arguments = NULL; 450 } 451 452 /* Pretend that this round went well, 453 * so that fail3 frees I-th 454 * fetch_context. */ 455 ++i; 456 goto fail3; 457 } 458 elem->arguments = nargs; 459 } 460 461 /* If it's not a syscall, we need to find the 462 * corresponding library symbol in the cloned 463 * library. */ 464 if (!elem->is_syscall && elem->c_un.libfunc != NULL) { 465 struct library_symbol *libfunc = elem->c_un.libfunc; 466 int rc = proc_find_symbol(retp, libfunc, 467 NULL, &elem->c_un.libfunc); 468 assert(rc == 0); 469 } 470 } 471 472 /* At this point, retp is fully initialized, except for OS and 473 * arch parts, and we can call private_process_destroy. */ 474 if (os_process_clone(retp, proc) < 0) { 475 private_process_destroy(retp, 0); 476 return -1; 477 } 478 if (arch_process_clone(retp, proc) < 0) { 479 os_process_destroy(retp); 480 private_process_destroy(retp, 0); 481 return -1; 482 } 483 484 return 0; 485 } 486 487 static int 488 open_one_pid(pid_t pid) 489 { 490 debug(DEBUG_PROCESS, "open_one_pid(pid=%d)", pid); 491 492 /* Get the filename first. Should the trace_pid fail, we can 493 * easily free it, untracing is more work. */ 494 char *filename = pid2name(pid); 495 if (filename == NULL || trace_pid(pid) < 0) { 496 fail: 497 free(filename); 498 return -1; 499 } 500 501 struct process *proc = open_program(filename, pid); 502 if (proc == NULL) 503 goto fail; 504 free(filename); 505 trace_set_options(proc); 506 507 return 0; 508 } 509 510 static enum callback_status 511 start_one_pid(struct process *proc, void *data) 512 { 513 continue_process(proc->pid); 514 return CBS_CONT; 515 } 516 517 static enum callback_status 518 is_main(struct process *proc, struct library *lib, void *data) 519 { 520 return CBS_STOP_IF(lib->type == LT_LIBTYPE_MAIN); 521 } 522 523 void 524 process_hit_start(struct process *proc) 525 { 526 struct process *leader = proc->leader; 527 assert(leader != NULL); 528 529 struct library *mainlib 530 = proc_each_library(leader, NULL, is_main, NULL); 531 assert(mainlib != NULL); 532 linkmap_init(leader, mainlib->dyn_addr); 533 arch_dynlink_done(leader); 534 } 535 536 void 537 open_pid(pid_t pid) 538 { 539 debug(DEBUG_PROCESS, "open_pid(pid=%d)", pid); 540 /* If we are already tracing this guy, we should be seeing all 541 * his children via normal tracing route. */ 542 if (pid2proc(pid) != NULL) 543 return; 544 545 /* First, see if we can attach the requested PID itself. */ 546 if (open_one_pid(pid) < 0) { 547 fprintf(stderr, "Cannot attach to pid %u: %s\n", 548 pid, strerror(errno)); 549 trace_fail_warning(pid); 550 return; 551 } 552 553 /* Now attach to all tasks that belong to that PID. There's a 554 * race between process_tasks and open_one_pid. So when we 555 * fail in open_one_pid below, we just do another round. 556 * Chances are that by then that PID will have gone away, and 557 * that's why we have seen the failure. The processes that we 558 * manage to open_one_pid are stopped, so we should eventually 559 * reach a point where process_tasks doesn't give any new 560 * processes (because there's nobody left to produce 561 * them). */ 562 size_t old_ntasks = 0; 563 int have_all; 564 while (1) { 565 pid_t *tasks; 566 size_t ntasks; 567 size_t i; 568 569 if (process_tasks(pid, &tasks, &ntasks) < 0) { 570 fprintf(stderr, "Cannot obtain tasks of pid %u: %s\n", 571 pid, strerror(errno)); 572 break; 573 } 574 575 have_all = 1; 576 for (i = 0; i < ntasks; ++i) 577 if (pid2proc(tasks[i]) == NULL 578 && open_one_pid(tasks[i]) < 0) 579 have_all = 0; 580 581 free(tasks); 582 583 if (have_all && old_ntasks == ntasks) 584 break; 585 old_ntasks = ntasks; 586 } 587 588 struct process *leader = pid2proc(pid)->leader; 589 590 /* XXX Is there a way to figure out whether _start has 591 * actually already been hit? */ 592 process_hit_start(leader); 593 594 /* Done. Continue everyone. */ 595 each_task(leader, NULL, start_one_pid, NULL); 596 } 597 598 static enum callback_status 599 find_proc(struct process *proc, void *data) 600 { 601 return CBS_STOP_IF(proc->pid == (pid_t)(uintptr_t)data); 602 } 603 604 struct process * 605 pid2proc(pid_t pid) 606 { 607 return each_process(NULL, &find_proc, (void *)(uintptr_t)pid); 608 } 609 610 static struct process *list_of_processes = NULL; 611 612 static void 613 unlist_process(struct process *proc) 614 { 615 if (list_of_processes == proc) { 616 list_of_processes = list_of_processes->next; 617 return; 618 } 619 620 struct process *tmp; 621 for (tmp = list_of_processes; ; tmp = tmp->next) { 622 /* If the following assert fails, the process wasn't 623 * in the list. */ 624 assert(tmp->next != NULL); 625 626 if (tmp->next == proc) { 627 tmp->next = tmp->next->next; 628 return; 629 } 630 } 631 } 632 633 struct process * 634 each_process(struct process *start_after, 635 enum callback_status(*cb)(struct process *proc, void *data), 636 void *data) 637 { 638 struct process *it = start_after == NULL ? list_of_processes 639 : start_after->next; 640 641 while (it != NULL) { 642 /* Callback might call remove_process. */ 643 struct process *next = it->next; 644 switch ((*cb)(it, data)) { 645 case CBS_FAIL: 646 /* XXX handle me */ 647 case CBS_STOP: 648 return it; 649 case CBS_CONT: 650 break; 651 } 652 it = next; 653 } 654 return NULL; 655 } 656 657 struct process * 658 each_task(struct process *proc, struct process *start_after, 659 enum callback_status(*cb)(struct process *proc, void *data), 660 void *data) 661 { 662 assert(proc != NULL); 663 struct process *it = start_after == NULL ? proc->leader 664 : start_after->next; 665 666 if (it != NULL) { 667 struct process *leader = it->leader; 668 while (it != NULL && it->leader == leader) { 669 /* Callback might call remove_process. */ 670 struct process *next = it->next; 671 switch ((*cb)(it, data)) { 672 case CBS_FAIL: 673 /* XXX handle me */ 674 case CBS_STOP: 675 return it; 676 case CBS_CONT: 677 break; 678 } 679 it = next; 680 } 681 } 682 return NULL; 683 } 684 685 static int 686 add_process(struct process *proc, int was_exec) 687 { 688 struct process **leaderp = &list_of_processes; 689 if (proc->pid) { 690 pid_t tgid = process_leader(proc->pid); 691 if (tgid == 0) 692 /* Must have been terminated before we managed 693 * to fully attach. */ 694 return -1; 695 if (tgid == proc->pid) { 696 proc->leader = proc; 697 } else { 698 struct process *leader = pid2proc(tgid); 699 proc->leader = leader; 700 if (leader != NULL) 701 leaderp = &leader->next; 702 } 703 } 704 705 if (!was_exec) { 706 proc->next = *leaderp; 707 *leaderp = proc; 708 } 709 return 0; 710 } 711 712 void 713 change_process_leader(struct process *proc, struct process *leader) 714 { 715 struct process **leaderp = &list_of_processes; 716 if (proc->leader == leader) 717 return; 718 719 assert(leader != NULL); 720 unlist_process(proc); 721 if (proc != leader) 722 leaderp = &leader->next; 723 724 proc->leader = leader; 725 proc->next = *leaderp; 726 *leaderp = proc; 727 } 728 729 static enum callback_status 730 clear_leader(struct process *proc, void *data) 731 { 732 debug(DEBUG_FUNCTION, "detach_task %d from leader %d", 733 proc->pid, proc->leader->pid); 734 proc->leader = NULL; 735 return CBS_CONT; 736 } 737 738 void 739 remove_process(struct process *proc) 740 { 741 debug(DEBUG_FUNCTION, "remove_proc(pid=%d)", proc->pid); 742 743 if (proc->leader == proc) 744 each_task(proc, NULL, &clear_leader, NULL); 745 746 unlist_process(proc); 747 process_removed(proc); 748 process_destroy(proc); 749 free(proc); 750 } 751 752 void 753 install_event_handler(struct process *proc, struct event_handler *handler) 754 { 755 debug(DEBUG_FUNCTION, "install_event_handler(pid=%d, %p)", proc->pid, handler); 756 assert(proc->event_handler == NULL); 757 proc->event_handler = handler; 758 } 759 760 void 761 destroy_event_handler(struct process *proc) 762 { 763 struct event_handler *handler = proc->event_handler; 764 debug(DEBUG_FUNCTION, "destroy_event_handler(pid=%d, %p)", proc->pid, handler); 765 assert(handler != NULL); 766 if (handler->destroy != NULL) 767 handler->destroy(handler); 768 free(handler); 769 proc->event_handler = NULL; 770 } 771 772 static int 773 breakpoint_for_symbol(struct library_symbol *libsym, struct process *proc) 774 { 775 arch_addr_t bp_addr; 776 assert(proc->leader == proc); 777 778 /* Don't enable latent or delayed symbols. */ 779 if (libsym->latent || libsym->delayed) { 780 debug(DEBUG_FUNCTION, 781 "delayed and/or latent breakpoint pid=%d, %s@%p", 782 proc->pid, libsym->name, libsym->enter_addr); 783 return 0; 784 } 785 786 bp_addr = sym2addr(proc, libsym); 787 788 /* If there is an artificial breakpoint on the same address, 789 * its libsym will be NULL, and we can smuggle our libsym 790 * there. That artificial breakpoint is there presumably for 791 * the callbacks, which we don't touch. If there is a real 792 * breakpoint, then this is a bug. ltrace-elf.c should filter 793 * symbols and ignore extra symbol aliases. 794 * 795 * The other direction is more complicated and currently not 796 * supported. If a breakpoint has custom callbacks, it might 797 * be also custom-allocated, and we would really need to swap 798 * the two: delete the one now in the dictionary, swap values 799 * around, and put the new breakpoint back in. */ 800 struct breakpoint *bp; 801 if (DICT_FIND_VAL(proc->breakpoints, &bp_addr, &bp) == 0) { 802 /* MIPS backend makes duplicate requests. This is 803 * likely a bug in the backend. Currently there's no 804 * point assigning more than one symbol to a 805 * breakpoint, because when it hits, we won't know 806 * what to print out. But it's easier to fix it here 807 * before someone who understands MIPS has the time to 808 * look into it. So turn the sanity check off on 809 * MIPS. References: 810 * 811 * http://lists.alioth.debian.org/pipermail/ltrace-devel/2012-November/000764.html 812 * http://lists.alioth.debian.org/pipermail/ltrace-devel/2012-November/000770.html 813 */ 814 #ifndef __mips__ 815 assert(bp->libsym == NULL); 816 bp->libsym = libsym; 817 #endif 818 return 0; 819 } 820 821 bp = malloc(sizeof(*bp)); 822 if (bp == NULL 823 || breakpoint_init(bp, proc, bp_addr, libsym) < 0) { 824 fail: 825 free(bp); 826 return -1; 827 } 828 if (proc_add_breakpoint(proc, bp) < 0) { 829 breakpoint_destroy(bp); 830 goto fail; 831 } 832 833 if (breakpoint_turn_on(bp, proc) < 0) { 834 proc_remove_breakpoint(proc, bp); 835 breakpoint_destroy(bp); 836 goto fail; 837 } 838 839 return 0; 840 } 841 842 static enum callback_status 843 cb_breakpoint_for_symbol(struct library_symbol *libsym, void *data) 844 { 845 return CBS_STOP_IF(breakpoint_for_symbol(libsym, data) < 0); 846 } 847 848 static int 849 proc_activate_latent_symbol(struct process *proc, 850 struct library_symbol *libsym) 851 { 852 assert(libsym->latent); 853 libsym->latent = 0; 854 debug(DEBUG_FUNCTION, "activated latent symbol"); 855 return breakpoint_for_symbol(libsym, proc); 856 } 857 858 int 859 proc_activate_delayed_symbol(struct process *proc, 860 struct library_symbol *libsym) 861 { 862 assert(libsym->delayed); 863 libsym->delayed = 0; 864 debug(DEBUG_FUNCTION, "activated delayed symbol"); 865 return breakpoint_for_symbol(libsym, proc); 866 } 867 868 static enum callback_status 869 activate_latent_in(struct process *proc, struct library *lib, void *data) 870 { 871 struct library_exported_name *exported; 872 for (exported = data; exported != NULL; exported = exported->next) { 873 struct library_symbol *libsym = NULL; 874 while ((libsym = library_each_symbol(lib, libsym, 875 library_symbol_named_cb, 876 (void *)exported->name)) 877 != NULL) 878 if (libsym->latent 879 && proc_activate_latent_symbol(proc, libsym) < 0) 880 return CBS_FAIL; 881 } 882 return CBS_CONT; 883 } 884 885 void 886 proc_add_library(struct process *proc, struct library *lib) 887 { 888 assert(lib->next == NULL); 889 lib->next = proc->libraries; 890 proc->libraries = lib; 891 debug(DEBUG_PROCESS, "added library %s@%p (%s) to %d", 892 lib->soname, lib->base, lib->pathname, proc->pid); 893 894 #if defined(HAVE_LIBDW) 895 if (options.bt_depth > 0) { 896 /* Setup module tracking for libdwfl unwinding. */ 897 struct process *leader = proc->leader; 898 Dwfl *dwfl = leader->dwfl; 899 if (dwfl == NULL) { 900 static const Dwfl_Callbacks proc_callbacks = { 901 .find_elf = dwfl_linux_proc_find_elf, 902 .find_debuginfo = dwfl_standard_find_debuginfo 903 }; 904 dwfl = dwfl_begin(&proc_callbacks); 905 if (dwfl == NULL) 906 fprintf(stderr, 907 "Couldn't initialize libdwfl unwinding " 908 "for process %d: %s\n", leader->pid, 909 dwfl_errmsg (-1)); 910 } 911 912 if (dwfl != NULL) { 913 dwfl_report_begin_add(dwfl); 914 if (dwfl_report_elf(dwfl, lib->soname, 915 lib->pathname, -1, 916 (GElf_Addr) lib->base, 917 false) == NULL) 918 fprintf(stderr, 919 "dwfl_report_elf %s@%p (%s) %d: %s\n", 920 lib->soname, lib->base, lib->pathname, 921 proc->pid, dwfl_errmsg (-1)); 922 dwfl_report_end(dwfl, NULL, NULL); 923 924 if (leader->dwfl == NULL) { 925 int r = dwfl_linux_proc_attach(dwfl, 926 leader->pid, 927 true); 928 if (r == 0) 929 leader->dwfl = dwfl; 930 else { 931 const char *msg; 932 dwfl_end(dwfl); 933 if (r < 0) 934 msg = dwfl_errmsg(-1); 935 else 936 msg = strerror(r); 937 fprintf(stderr, "Couldn't initialize " 938 "libdwfl unwinding for " 939 "process %d: %s\n", 940 leader->pid, msg); 941 } 942 } 943 } 944 } 945 #endif /* defined(HAVE_LIBDW) */ 946 947 /* Insert breakpoints for all active (non-latent) symbols. */ 948 struct library_symbol *libsym = NULL; 949 while ((libsym = library_each_symbol(lib, libsym, 950 cb_breakpoint_for_symbol, 951 proc)) != NULL) 952 fprintf(stderr, 953 "Couldn't insert breakpoint for %s to %d: %s.\n", 954 libsym->name, proc->pid, strerror(errno)); 955 956 /* Look through export list of the new library and compare it 957 * with latent symbols of all libraries (including this 958 * library itself). */ 959 struct library *lib2 = NULL; 960 while ((lib2 = proc_each_library(proc, lib2, activate_latent_in, 961 lib->exported_names)) != NULL) 962 fprintf(stderr, 963 "Couldn't activate latent symbols for %s in %d: %s.\n", 964 lib2->soname, proc->pid, strerror(errno)); 965 } 966 967 int 968 proc_remove_library(struct process *proc, struct library *lib) 969 { 970 struct library **libp; 971 for (libp = &proc->libraries; *libp != NULL; libp = &(*libp)->next) 972 if (*libp == lib) { 973 *libp = lib->next; 974 return 0; 975 } 976 return -1; 977 } 978 979 struct library * 980 proc_each_library(struct process *proc, struct library *it, 981 enum callback_status (*cb)(struct process *proc, 982 struct library *lib, void *data), 983 void *data) 984 { 985 if (it == NULL) 986 it = proc->libraries; 987 else 988 it = it->next; 989 990 while (it != NULL) { 991 struct library *next = it->next; 992 993 switch (cb(proc, it, data)) { 994 case CBS_FAIL: 995 /* XXX handle me */ 996 case CBS_STOP: 997 return it; 998 case CBS_CONT: 999 break; 1000 } 1001 1002 it = next; 1003 } 1004 1005 return NULL; 1006 } 1007 1008 static void 1009 check_leader(struct process *proc) 1010 { 1011 /* Only the group leader should be getting the breakpoints and 1012 * thus have ->breakpoint initialized. */ 1013 assert(proc->leader != NULL); 1014 assert(proc->leader == proc); 1015 assert(proc->breakpoints != NULL); 1016 } 1017 1018 int 1019 proc_add_breakpoint(struct process *proc, struct breakpoint *bp) 1020 { 1021 debug(DEBUG_FUNCTION, "proc_add_breakpoint(pid=%d, %s@%p)", 1022 proc->pid, breakpoint_name(bp), bp->addr); 1023 check_leader(proc); 1024 1025 /* XXX We might merge bp->libsym instead of the following 1026 * assert, but that's not necessary right now. Read the 1027 * comment in breakpoint_for_symbol. */ 1028 assert(dict_find(proc->breakpoints, &bp->addr) == NULL); 1029 1030 if (DICT_INSERT(proc->breakpoints, &bp->addr, &bp) < 0) { 1031 fprintf(stderr, 1032 "couldn't enter breakpoint %s@%p to dictionary: %s\n", 1033 breakpoint_name(bp), bp->addr, strerror(errno)); 1034 return -1; 1035 } 1036 1037 return 0; 1038 } 1039 1040 void 1041 proc_remove_breakpoint(struct process *proc, struct breakpoint *bp) 1042 { 1043 debug(DEBUG_FUNCTION, "proc_remove_breakpoint(pid=%d, %s@%p)", 1044 proc->pid, breakpoint_name(bp), bp->addr); 1045 check_leader(proc); 1046 int rc = DICT_ERASE(proc->breakpoints, &bp->addr, struct breakpoint *, 1047 NULL, NULL, NULL); 1048 assert(rc == 0); 1049 } 1050 1051 struct each_breakpoint_data 1052 { 1053 struct process *proc; 1054 enum callback_status (*cb)(struct process *proc, 1055 struct breakpoint *bp, 1056 void *data); 1057 void *cb_data; 1058 }; 1059 1060 static enum callback_status 1061 each_breakpoint_cb(arch_addr_t *key, struct breakpoint **bpp, void *d) 1062 { 1063 struct each_breakpoint_data *data = d; 1064 return data->cb(data->proc, *bpp, data->cb_data); 1065 } 1066 1067 arch_addr_t * 1068 proc_each_breakpoint(struct process *proc, arch_addr_t *start, 1069 enum callback_status (*cb)(struct process *proc, 1070 struct breakpoint *bp, 1071 void *data), void *data) 1072 { 1073 struct each_breakpoint_data dd = { 1074 .proc = proc, 1075 .cb = cb, 1076 .cb_data = data, 1077 }; 1078 return DICT_EACH(proc->breakpoints, 1079 arch_addr_t, struct breakpoint *, start, 1080 &each_breakpoint_cb, &dd); 1081 } 1082 1083 int 1084 proc_find_symbol(struct process *proc, struct library_symbol *sym, 1085 struct library **retlib, struct library_symbol **retsym) 1086 { 1087 struct library *lib = sym->lib; 1088 assert(lib != NULL); 1089 1090 struct library *flib 1091 = proc_each_library(proc, NULL, library_with_key_cb, &lib->key); 1092 if (flib == NULL) 1093 return -1; 1094 1095 struct library_symbol *fsym 1096 = library_each_symbol(flib, NULL, library_symbol_named_cb, 1097 (char *)sym->name); 1098 if (fsym == NULL) 1099 return -1; 1100 1101 if (retlib != NULL) 1102 *retlib = flib; 1103 if (retsym != NULL) 1104 *retsym = fsym; 1105 1106 return 0; 1107 } 1108 1109 struct library_symbol * 1110 proc_each_symbol(struct process *proc, struct library_symbol *start_after, 1111 enum callback_status (*cb)(struct library_symbol *, void *), 1112 void *data) 1113 { 1114 struct library *lib; 1115 for (lib = start_after != NULL ? start_after->lib : proc->libraries; 1116 lib != NULL; lib = lib->next) { 1117 start_after = library_each_symbol(lib, start_after, cb, data); 1118 if (start_after != NULL) 1119 return start_after; 1120 } 1121 1122 return NULL; 1123 } 1124 1125 #define DEF_READER(NAME, SIZE) \ 1126 int \ 1127 NAME(struct process *proc, arch_addr_t addr, \ 1128 uint##SIZE##_t *lp) \ 1129 { \ 1130 union { \ 1131 uint##SIZE##_t dst; \ 1132 char buf[0]; \ 1133 } u; \ 1134 if (umovebytes(proc, addr, &u.buf, sizeof(u.dst)) \ 1135 != sizeof(u.dst)) \ 1136 return -1; \ 1137 *lp = u.dst; \ 1138 return 0; \ 1139 } 1140 1141 DEF_READER(proc_read_8, 8) 1142 DEF_READER(proc_read_16, 16) 1143 DEF_READER(proc_read_32, 32) 1144 DEF_READER(proc_read_64, 64) 1145 1146 #undef DEF_READER 1147
