1 /* system/debuggerd/debuggerd.c 2 ** 3 ** Copyright 2006, The Android Open Source Project 4 ** 5 ** Licensed under the Apache License, Version 2.0 (the "License"); 6 ** you may not use this file except in compliance with the License. 7 ** You may obtain a copy of the License at 8 ** 9 ** http://www.apache.org/licenses/LICENSE-2.0 10 ** 11 ** Unless required by applicable law or agreed to in writing, software 12 ** distributed under the License is distributed on an "AS IS" BASIS, 13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 ** See the License for the specific language governing permissions and 15 ** limitations under the License. 16 */ 17 18 #include <stdio.h> 19 #include <stdlib.h> 20 #include <unistd.h> 21 #include <errno.h> 22 #include <signal.h> 23 #include <pthread.h> 24 #include <stdarg.h> 25 #include <fcntl.h> 26 #include <sys/types.h> 27 #include <dirent.h> 28 29 #include <sys/ptrace.h> 30 #include <sys/wait.h> 31 #include <sys/exec_elf.h> 32 #include <sys/stat.h> 33 34 #include <cutils/sockets.h> 35 #include <cutils/logd.h> 36 #include <cutils/sockets.h> 37 #include <cutils/properties.h> 38 39 #include <linux/input.h> 40 41 #include <private/android_filesystem_config.h> 42 43 #include "utility.h" 44 45 #ifdef WITH_VFP 46 #ifdef WITH_VFP_D32 47 #define NUM_VFP_REGS 32 48 #else 49 #define NUM_VFP_REGS 16 50 #endif 51 #endif 52 53 /* Main entry point to get the backtrace from the crashing process */ 54 extern int unwind_backtrace_with_ptrace(int tfd, pid_t pid, mapinfo *map, 55 unsigned int sp_list[], 56 int *frame0_pc_sane, 57 bool at_fault); 58 59 static int logsocket = -1; 60 61 #define ANDROID_LOG_INFO 4 62 63 /* Log information onto the tombstone */ 64 void _LOG(int tfd, bool in_tombstone_only, const char *fmt, ...) 65 { 66 char buf[128]; 67 68 va_list ap; 69 va_start(ap, fmt); 70 71 if (tfd >= 0) { 72 int len; 73 vsnprintf(buf, sizeof(buf), fmt, ap); 74 len = strlen(buf); 75 if(tfd >= 0) write(tfd, buf, len); 76 } 77 78 if (!in_tombstone_only) 79 __android_log_vprint(ANDROID_LOG_INFO, "DEBUG", fmt, ap); 80 } 81 82 #define LOG(fmt...) _LOG(-1, 0, fmt) 83 #if 0 84 #define XLOG(fmt...) _LOG(-1, 0, fmt) 85 #else 86 #define XLOG(fmt...) do {} while(0) 87 #endif 88 89 // 6f000000-6f01e000 rwxp 00000000 00:0c 16389419 /system/lib/libcomposer.so 90 // 012345678901234567890123456789012345678901234567890123456789 91 // 0 1 2 3 4 5 92 93 mapinfo *parse_maps_line(char *line) 94 { 95 mapinfo *mi; 96 int len = strlen(line); 97 98 if(len < 1) return 0; 99 line[--len] = 0; 100 101 if(len < 50) return 0; 102 if(line[20] != 'x') return 0; 103 104 mi = malloc(sizeof(mapinfo) + (len - 47)); 105 if(mi == 0) return 0; 106 107 mi->start = strtoul(line, 0, 16); 108 mi->end = strtoul(line + 9, 0, 16); 109 /* To be filled in parse_exidx_info if the mapped section starts with 110 * elf_header 111 */ 112 mi->exidx_start = mi->exidx_end = 0; 113 mi->next = 0; 114 strcpy(mi->name, line + 49); 115 116 return mi; 117 } 118 119 void dump_build_info(int tfd) 120 { 121 char fingerprint[PROPERTY_VALUE_MAX]; 122 123 property_get("ro.build.fingerprint", fingerprint, "unknown"); 124 125 _LOG(tfd, false, "Build fingerprint: '%s'\n", fingerprint); 126 } 127 128 129 void dump_stack_and_code(int tfd, int pid, mapinfo *map, 130 int unwind_depth, unsigned int sp_list[], 131 bool at_fault) 132 { 133 unsigned int sp, pc, p, end, data; 134 struct pt_regs r; 135 int sp_depth; 136 bool only_in_tombstone = !at_fault; 137 char code_buffer[80]; 138 139 if(ptrace(PTRACE_GETREGS, pid, 0, &r)) return; 140 sp = r.ARM_sp; 141 pc = r.ARM_pc; 142 143 _LOG(tfd, only_in_tombstone, "\ncode around pc:\n"); 144 145 end = p = pc & ~3; 146 p -= 32; 147 end += 32; 148 149 /* Dump the code around PC as: 150 * addr contents 151 * 00008d34 fffffcd0 4c0eb530 b0934a0e 1c05447c 152 * 00008d44 f7ff18a0 490ced94 68035860 d0012b00 153 */ 154 while (p <= end) { 155 int i; 156 157 sprintf(code_buffer, "%08x ", p); 158 for (i = 0; i < 4; i++) { 159 data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL); 160 sprintf(code_buffer + strlen(code_buffer), "%08x ", data); 161 p += 4; 162 } 163 _LOG(tfd, only_in_tombstone, "%s\n", code_buffer); 164 } 165 166 if ((unsigned) r.ARM_lr != pc) { 167 _LOG(tfd, only_in_tombstone, "\ncode around lr:\n"); 168 169 end = p = r.ARM_lr & ~3; 170 p -= 32; 171 end += 32; 172 173 /* Dump the code around LR as: 174 * addr contents 175 * 00008d34 fffffcd0 4c0eb530 b0934a0e 1c05447c 176 * 00008d44 f7ff18a0 490ced94 68035860 d0012b00 177 */ 178 while (p <= end) { 179 int i; 180 181 sprintf(code_buffer, "%08x ", p); 182 for (i = 0; i < 4; i++) { 183 data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL); 184 sprintf(code_buffer + strlen(code_buffer), "%08x ", data); 185 p += 4; 186 } 187 _LOG(tfd, only_in_tombstone, "%s\n", code_buffer); 188 } 189 } 190 191 p = sp - 64; 192 p &= ~3; 193 if (unwind_depth != 0) { 194 if (unwind_depth < STACK_CONTENT_DEPTH) { 195 end = sp_list[unwind_depth-1]; 196 } 197 else { 198 end = sp_list[STACK_CONTENT_DEPTH-1]; 199 } 200 } 201 else { 202 end = sp | 0x000000ff; 203 end += 0xff; 204 } 205 206 _LOG(tfd, only_in_tombstone, "\nstack:\n"); 207 208 /* If the crash is due to PC == 0, there will be two frames that 209 * have identical SP value. 210 */ 211 if (sp_list[0] == sp_list[1]) { 212 sp_depth = 1; 213 } 214 else { 215 sp_depth = 0; 216 } 217 218 while (p <= end) { 219 char *prompt; 220 char level[16]; 221 data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL); 222 if (p == sp_list[sp_depth]) { 223 sprintf(level, "#%02d", sp_depth++); 224 prompt = level; 225 } 226 else { 227 prompt = " "; 228 } 229 230 /* Print the stack content in the log for the first 3 frames. For the 231 * rest only print them in the tombstone file. 232 */ 233 _LOG(tfd, (sp_depth > 2) || only_in_tombstone, 234 "%s %08x %08x %s\n", prompt, p, data, 235 map_to_name(map, data, "")); 236 p += 4; 237 } 238 /* print another 64-byte of stack data after the last frame */ 239 240 end = p+64; 241 while (p <= end) { 242 data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL); 243 _LOG(tfd, (sp_depth > 2) || only_in_tombstone, 244 " %08x %08x %s\n", p, data, 245 map_to_name(map, data, "")); 246 p += 4; 247 } 248 } 249 250 void dump_pc_and_lr(int tfd, int pid, mapinfo *map, int unwound_level, 251 bool at_fault) 252 { 253 struct pt_regs r; 254 255 if(ptrace(PTRACE_GETREGS, pid, 0, &r)) { 256 _LOG(tfd, !at_fault, "tid %d not responding!\n", pid); 257 return; 258 } 259 260 if (unwound_level == 0) { 261 _LOG(tfd, !at_fault, " #%02d pc %08x %s\n", 0, r.ARM_pc, 262 map_to_name(map, r.ARM_pc, "<unknown>")); 263 } 264 _LOG(tfd, !at_fault, " #%02d lr %08x %s\n", 1, r.ARM_lr, 265 map_to_name(map, r.ARM_lr, "<unknown>")); 266 } 267 268 void dump_registers(int tfd, int pid, bool at_fault) 269 { 270 struct pt_regs r; 271 bool only_in_tombstone = !at_fault; 272 273 if(ptrace(PTRACE_GETREGS, pid, 0, &r)) { 274 _LOG(tfd, only_in_tombstone, 275 "cannot get registers: %s\n", strerror(errno)); 276 return; 277 } 278 279 _LOG(tfd, only_in_tombstone, " r0 %08x r1 %08x r2 %08x r3 %08x\n", 280 r.ARM_r0, r.ARM_r1, r.ARM_r2, r.ARM_r3); 281 _LOG(tfd, only_in_tombstone, " r4 %08x r5 %08x r6 %08x r7 %08x\n", 282 r.ARM_r4, r.ARM_r5, r.ARM_r6, r.ARM_r7); 283 _LOG(tfd, only_in_tombstone, " r8 %08x r9 %08x 10 %08x fp %08x\n", 284 r.ARM_r8, r.ARM_r9, r.ARM_r10, r.ARM_fp); 285 _LOG(tfd, only_in_tombstone, 286 " ip %08x sp %08x lr %08x pc %08x cpsr %08x\n", 287 r.ARM_ip, r.ARM_sp, r.ARM_lr, r.ARM_pc, r.ARM_cpsr); 288 289 #ifdef WITH_VFP 290 struct user_vfp vfp_regs; 291 int i; 292 293 if(ptrace(PTRACE_GETVFPREGS, pid, 0, &vfp_regs)) { 294 _LOG(tfd, only_in_tombstone, 295 "cannot get registers: %s\n", strerror(errno)); 296 return; 297 } 298 299 for (i = 0; i < NUM_VFP_REGS; i += 2) { 300 _LOG(tfd, only_in_tombstone, 301 " d%-2d %016llx d%-2d %016llx\n", 302 i, vfp_regs.fpregs[i], i+1, vfp_regs.fpregs[i+1]); 303 } 304 _LOG(tfd, only_in_tombstone, " scr %08lx\n\n", vfp_regs.fpscr); 305 #endif 306 } 307 308 const char *get_signame(int sig) 309 { 310 switch(sig) { 311 case SIGILL: return "SIGILL"; 312 case SIGABRT: return "SIGABRT"; 313 case SIGBUS: return "SIGBUS"; 314 case SIGFPE: return "SIGFPE"; 315 case SIGSEGV: return "SIGSEGV"; 316 case SIGSTKFLT: return "SIGSTKFLT"; 317 default: return "?"; 318 } 319 } 320 321 void dump_fault_addr(int tfd, int pid, int sig) 322 { 323 siginfo_t si; 324 325 memset(&si, 0, sizeof(si)); 326 if(ptrace(PTRACE_GETSIGINFO, pid, 0, &si)){ 327 _LOG(tfd, false, "cannot get siginfo: %s\n", strerror(errno)); 328 } else { 329 _LOG(tfd, false, "signal %d (%s), fault addr %08x\n", 330 sig, get_signame(sig), si.si_addr); 331 } 332 } 333 334 void dump_crash_banner(int tfd, unsigned pid, unsigned tid, int sig) 335 { 336 char data[1024]; 337 char *x = 0; 338 FILE *fp; 339 340 sprintf(data, "/proc/%d/cmdline", pid); 341 fp = fopen(data, "r"); 342 if(fp) { 343 x = fgets(data, 1024, fp); 344 fclose(fp); 345 } 346 347 _LOG(tfd, false, 348 "*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n"); 349 dump_build_info(tfd); 350 _LOG(tfd, false, "pid: %d, tid: %d >>> %s <<<\n", 351 pid, tid, x ? x : "UNKNOWN"); 352 353 if(sig) dump_fault_addr(tfd, tid, sig); 354 } 355 356 static void parse_exidx_info(mapinfo *milist, pid_t pid) 357 { 358 mapinfo *mi; 359 for (mi = milist; mi != NULL; mi = mi->next) { 360 Elf32_Ehdr ehdr; 361 362 memset(&ehdr, 0, sizeof(Elf32_Ehdr)); 363 /* Read in sizeof(Elf32_Ehdr) worth of data from the beginning of 364 * mapped section. 365 */ 366 get_remote_struct(pid, (void *) (mi->start), &ehdr, 367 sizeof(Elf32_Ehdr)); 368 /* Check if it has the matching magic words */ 369 if (IS_ELF(ehdr)) { 370 Elf32_Phdr phdr; 371 Elf32_Phdr *ptr; 372 int i; 373 374 ptr = (Elf32_Phdr *) (mi->start + ehdr.e_phoff); 375 for (i = 0; i < ehdr.e_phnum; i++) { 376 /* Parse the program header */ 377 get_remote_struct(pid, (char *) ptr+i, &phdr, 378 sizeof(Elf32_Phdr)); 379 /* Found a EXIDX segment? */ 380 if (phdr.p_type == PT_ARM_EXIDX) { 381 mi->exidx_start = mi->start + phdr.p_offset; 382 mi->exidx_end = mi->exidx_start + phdr.p_filesz; 383 break; 384 } 385 } 386 } 387 } 388 } 389 390 void dump_crash_report(int tfd, unsigned pid, unsigned tid, bool at_fault) 391 { 392 char data[1024]; 393 FILE *fp; 394 mapinfo *milist = 0; 395 unsigned int sp_list[STACK_CONTENT_DEPTH]; 396 int stack_depth; 397 int frame0_pc_sane = 1; 398 399 if (!at_fault) { 400 _LOG(tfd, true, 401 "--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---\n"); 402 _LOG(tfd, true, "pid: %d, tid: %d\n", pid, tid); 403 } 404 405 dump_registers(tfd, tid, at_fault); 406 407 /* Clear stack pointer records */ 408 memset(sp_list, 0, sizeof(sp_list)); 409 410 sprintf(data, "/proc/%d/maps", pid); 411 fp = fopen(data, "r"); 412 if(fp) { 413 while(fgets(data, 1024, fp)) { 414 mapinfo *mi = parse_maps_line(data); 415 if(mi) { 416 mi->next = milist; 417 milist = mi; 418 } 419 } 420 fclose(fp); 421 } 422 423 parse_exidx_info(milist, tid); 424 425 /* If stack unwinder fails, use the default solution to dump the stack 426 * content. 427 */ 428 stack_depth = unwind_backtrace_with_ptrace(tfd, tid, milist, sp_list, 429 &frame0_pc_sane, at_fault); 430 431 /* The stack unwinder should at least unwind two levels of stack. If less 432 * level is seen we make sure at lease pc and lr are dumped. 433 */ 434 if (stack_depth < 2) { 435 dump_pc_and_lr(tfd, tid, milist, stack_depth, at_fault); 436 } 437 438 dump_stack_and_code(tfd, tid, milist, stack_depth, sp_list, at_fault); 439 440 while(milist) { 441 mapinfo *next = milist->next; 442 free(milist); 443 milist = next; 444 } 445 } 446 447 #define MAX_TOMBSTONES 10 448 449 #define typecheck(x,y) { \ 450 typeof(x) __dummy1; \ 451 typeof(y) __dummy2; \ 452 (void)(&__dummy1 == &__dummy2); } 453 454 #define TOMBSTONE_DIR "/data/tombstones" 455 456 /* 457 * find_and_open_tombstone - find an available tombstone slot, if any, of the 458 * form tombstone_XX where XX is 00 to MAX_TOMBSTONES-1, inclusive. If no 459 * file is available, we reuse the least-recently-modified file. 460 */ 461 static int find_and_open_tombstone(void) 462 { 463 unsigned long mtime = ULONG_MAX; 464 struct stat sb; 465 char path[128]; 466 int fd, i, oldest = 0; 467 468 /* 469 * XXX: Our stat.st_mtime isn't time_t. If it changes, as it probably ought 470 * to, our logic breaks. This check will generate a warning if that happens. 471 */ 472 typecheck(mtime, sb.st_mtime); 473 474 /* 475 * In a single wolf-like pass, find an available slot and, in case none 476 * exist, find and record the least-recently-modified file. 477 */ 478 for (i = 0; i < MAX_TOMBSTONES; i++) { 479 snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", i); 480 481 if (!stat(path, &sb)) { 482 if (sb.st_mtime < mtime) { 483 oldest = i; 484 mtime = sb.st_mtime; 485 } 486 continue; 487 } 488 if (errno != ENOENT) 489 continue; 490 491 fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0600); 492 if (fd < 0) 493 continue; /* raced ? */ 494 495 fchown(fd, AID_SYSTEM, AID_SYSTEM); 496 return fd; 497 } 498 499 /* we didn't find an available file, so we clobber the oldest one */ 500 snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", oldest); 501 fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600); 502 fchown(fd, AID_SYSTEM, AID_SYSTEM); 503 504 return fd; 505 } 506 507 /* Return true if some thread is not detached cleanly */ 508 static bool dump_sibling_thread_report(int tfd, unsigned pid, unsigned tid) 509 { 510 char task_path[1024]; 511 512 sprintf(task_path, "/proc/%d/task", pid); 513 DIR *d; 514 struct dirent *de; 515 int need_cleanup = 0; 516 517 d = opendir(task_path); 518 /* Bail early if cannot open the task directory */ 519 if (d == NULL) { 520 XLOG("Cannot open /proc/%d/task\n", pid); 521 return false; 522 } 523 while ((de = readdir(d)) != NULL) { 524 unsigned new_tid; 525 /* Ignore "." and ".." */ 526 if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) 527 continue; 528 new_tid = atoi(de->d_name); 529 /* The main thread at fault has been handled individually */ 530 if (new_tid == tid) 531 continue; 532 533 /* Skip this thread if cannot ptrace it */ 534 if (ptrace(PTRACE_ATTACH, new_tid, 0, 0) < 0) 535 continue; 536 537 dump_crash_report(tfd, pid, new_tid, false); 538 need_cleanup |= ptrace(PTRACE_DETACH, new_tid, 0, 0); 539 } 540 closedir(d); 541 return need_cleanup != 0; 542 } 543 544 /* Return true if some thread is not detached cleanly */ 545 static bool engrave_tombstone(unsigned pid, unsigned tid, int debug_uid, 546 int signal) 547 { 548 int fd; 549 bool need_cleanup = false; 550 551 mkdir(TOMBSTONE_DIR, 0755); 552 chown(TOMBSTONE_DIR, AID_SYSTEM, AID_SYSTEM); 553 554 fd = find_and_open_tombstone(); 555 if (fd < 0) 556 return need_cleanup; 557 558 dump_crash_banner(fd, pid, tid, signal); 559 dump_crash_report(fd, pid, tid, true); 560 /* 561 * If the user has requested to attach gdb, don't collect the per-thread 562 * information as it increases the chance to lose track of the process. 563 */ 564 if ((signed)pid > debug_uid) { 565 need_cleanup = dump_sibling_thread_report(fd, pid, tid); 566 } 567 568 close(fd); 569 return need_cleanup; 570 } 571 572 static int 573 write_string(const char* file, const char* string) 574 { 575 int len; 576 int fd; 577 ssize_t amt; 578 fd = open(file, O_RDWR); 579 len = strlen(string); 580 if (fd < 0) 581 return -errno; 582 amt = write(fd, string, len); 583 close(fd); 584 return amt >= 0 ? 0 : -errno; 585 } 586 587 static 588 void init_debug_led(void) 589 { 590 // trout leds 591 write_string("/sys/class/leds/red/brightness", "0"); 592 write_string("/sys/class/leds/green/brightness", "0"); 593 write_string("/sys/class/leds/blue/brightness", "0"); 594 write_string("/sys/class/leds/red/device/blink", "0"); 595 // sardine leds 596 write_string("/sys/class/leds/left/cadence", "0,0"); 597 } 598 599 static 600 void enable_debug_led(void) 601 { 602 // trout leds 603 write_string("/sys/class/leds/red/brightness", "255"); 604 // sardine leds 605 write_string("/sys/class/leds/left/cadence", "1,0"); 606 } 607 608 static 609 void disable_debug_led(void) 610 { 611 // trout leds 612 write_string("/sys/class/leds/red/brightness", "0"); 613 // sardine leds 614 write_string("/sys/class/leds/left/cadence", "0,0"); 615 } 616 617 extern int init_getevent(); 618 extern void uninit_getevent(); 619 extern int get_event(struct input_event* event, int timeout); 620 621 static void wait_for_user_action(unsigned tid, struct ucred* cr) 622 { 623 (void)tid; 624 /* First log a helpful message */ 625 LOG( "********************************************************\n" 626 "* Process %d has been suspended while crashing. To\n" 627 "* attach gdbserver for a gdb connection on port 5039:\n" 628 "*\n" 629 "* adb shell gdbserver :5039 --attach %d &\n" 630 "*\n" 631 "* Press HOME key to let the process continue crashing.\n" 632 "********************************************************\n", 633 cr->pid, cr->pid); 634 635 /* wait for HOME key (TODO: something useful for devices w/o HOME key) */ 636 if (init_getevent() == 0) { 637 int ms = 1200 / 10; 638 int dit = 1; 639 int dah = 3*dit; 640 int _ = -dit; 641 int ___ = 3*_; 642 int _______ = 7*_; 643 const signed char codes[] = { 644 dit,_,dit,_,dit,___,dah,_,dah,_,dah,___,dit,_,dit,_,dit,_______ 645 }; 646 size_t s = 0; 647 struct input_event e; 648 int home = 0; 649 init_debug_led(); 650 enable_debug_led(); 651 do { 652 int timeout = abs((int)(codes[s])) * ms; 653 int res = get_event(&e, timeout); 654 if (res == 0) { 655 if (e.type==EV_KEY && e.code==KEY_HOME && e.value==0) 656 home = 1; 657 } else if (res == 1) { 658 if (++s >= sizeof(codes)/sizeof(*codes)) 659 s = 0; 660 if (codes[s] > 0) { 661 enable_debug_led(); 662 } else { 663 disable_debug_led(); 664 } 665 } 666 } while (!home); 667 uninit_getevent(); 668 } 669 670 /* don't forget to turn debug led off */ 671 disable_debug_led(); 672 673 /* close filedescriptor */ 674 LOG("debuggerd resuming process %d", cr->pid); 675 } 676 677 static void handle_crashing_process(int fd) 678 { 679 char buf[64]; 680 struct stat s; 681 unsigned tid; 682 struct ucred cr; 683 int n, len, status; 684 int tid_attach_status = -1; 685 unsigned retry = 30; 686 bool need_cleanup = false; 687 688 char value[PROPERTY_VALUE_MAX]; 689 property_get("debug.db.uid", value, "-1"); 690 int debug_uid = atoi(value); 691 692 XLOG("handle_crashing_process(%d)\n", fd); 693 694 len = sizeof(cr); 695 n = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &len); 696 if(n != 0) { 697 LOG("cannot get credentials\n"); 698 goto done; 699 } 700 701 XLOG("reading tid\n"); 702 fcntl(fd, F_SETFL, O_NONBLOCK); 703 while((n = read(fd, &tid, sizeof(unsigned))) != sizeof(unsigned)) { 704 if(errno == EINTR) continue; 705 if(errno == EWOULDBLOCK) { 706 if(retry-- > 0) { 707 usleep(100 * 1000); 708 continue; 709 } 710 LOG("timed out reading tid\n"); 711 goto done; 712 } 713 LOG("read failure? %s\n", strerror(errno)); 714 goto done; 715 } 716 717 sprintf(buf,"/proc/%d/task/%d", cr.pid, tid); 718 if(stat(buf, &s)) { 719 LOG("tid %d does not exist in pid %d. ignoring debug request\n", 720 tid, cr.pid); 721 close(fd); 722 return; 723 } 724 725 XLOG("BOOM: pid=%d uid=%d gid=%d tid=%d\n", cr.pid, cr.uid, cr.gid, tid); 726 727 tid_attach_status = ptrace(PTRACE_ATTACH, tid, 0, 0); 728 if(tid_attach_status < 0) { 729 LOG("ptrace attach failed: %s\n", strerror(errno)); 730 goto done; 731 } 732 733 close(fd); 734 fd = -1; 735 736 for(;;) { 737 n = waitpid(tid, &status, __WALL); 738 739 if(n < 0) { 740 if(errno == EAGAIN) continue; 741 LOG("waitpid failed: %s\n", strerror(errno)); 742 goto done; 743 } 744 745 XLOG("waitpid: n=%d status=%08x\n", n, status); 746 747 if(WIFSTOPPED(status)){ 748 n = WSTOPSIG(status); 749 switch(n) { 750 case SIGSTOP: 751 XLOG("stopped -- continuing\n"); 752 n = ptrace(PTRACE_CONT, tid, 0, 0); 753 if(n) { 754 LOG("ptrace failed: %s\n", strerror(errno)); 755 goto done; 756 } 757 continue; 758 759 case SIGILL: 760 case SIGABRT: 761 case SIGBUS: 762 case SIGFPE: 763 case SIGSEGV: 764 case SIGSTKFLT: { 765 XLOG("stopped -- fatal signal\n"); 766 need_cleanup = engrave_tombstone(cr.pid, tid, debug_uid, n); 767 kill(tid, SIGSTOP); 768 goto done; 769 } 770 771 default: 772 XLOG("stopped -- unexpected signal\n"); 773 goto done; 774 } 775 } else { 776 XLOG("unexpected waitpid response\n"); 777 goto done; 778 } 779 } 780 781 done: 782 XLOG("detaching\n"); 783 784 /* stop the process so we can debug */ 785 kill(cr.pid, SIGSTOP); 786 787 /* 788 * If a thread has been attached by ptrace, make sure it is detached 789 * successfully otherwise we will get a zombie. 790 */ 791 if (tid_attach_status == 0) { 792 int detach_status; 793 /* detach so we can attach gdbserver */ 794 detach_status = ptrace(PTRACE_DETACH, tid, 0, 0); 795 need_cleanup |= (detach_status != 0); 796 } 797 798 /* 799 * if debug.db.uid is set, its value indicates if we should wait 800 * for user action for the crashing process. 801 * in this case, we log a message and turn the debug LED on 802 * waiting for a gdb connection (for instance) 803 */ 804 805 if ((signed)cr.uid <= debug_uid) { 806 wait_for_user_action(tid, &cr); 807 } 808 809 /* resume stopped process (so it can crash in peace) */ 810 kill(cr.pid, SIGCONT); 811 812 if (need_cleanup) { 813 LOG("debuggerd committing suicide to free the zombie!\n"); 814 kill(getpid(), SIGKILL); 815 } 816 817 if(fd != -1) close(fd); 818 } 819 820 int main() 821 { 822 int s; 823 struct sigaction act; 824 825 logsocket = socket_local_client("logd", 826 ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_DGRAM); 827 if(logsocket < 0) { 828 logsocket = -1; 829 } else { 830 fcntl(logsocket, F_SETFD, FD_CLOEXEC); 831 } 832 833 act.sa_handler = SIG_DFL; 834 sigemptyset(&act.sa_mask); 835 sigaddset(&act.sa_mask,SIGCHLD); 836 act.sa_flags = SA_NOCLDWAIT; 837 sigaction(SIGCHLD, &act, 0); 838 839 s = socket_local_server("android:debuggerd", 840 ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM); 841 if(s < 0) return -1; 842 fcntl(s, F_SETFD, FD_CLOEXEC); 843 844 LOG("debuggerd: " __DATE__ " " __TIME__ "\n"); 845 846 for(;;) { 847 struct sockaddr addr; 848 socklen_t alen; 849 int fd; 850 851 alen = sizeof(addr); 852 fd = accept(s, &addr, &alen); 853 if(fd < 0) continue; 854 855 fcntl(fd, F_SETFD, FD_CLOEXEC); 856 857 handle_crashing_process(fd); 858 } 859 return 0; 860 } 861
