debuggerd.c revision 3bfdcc979da0f857b014318f3df5d95a0f93eb27
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/* Main entry point to get the backtrace from the crashing process */ 46extern int unwind_backtrace_with_ptrace(int tfd, pid_t pid, mapinfo *map, 47 unsigned int sp_list[], 48 int *frame0_pc_sane, 49 bool at_fault); 50 51static int logsocket = -1; 52 53#define ANDROID_LOG_INFO 4 54 55/* Log information onto the tombstone */ 56void _LOG(int tfd, bool in_tombstone_only, const char *fmt, ...) 57{ 58 char buf[128]; 59 60 va_list ap; 61 va_start(ap, fmt); 62 63 if (tfd >= 0) { 64 int len; 65 vsnprintf(buf, sizeof(buf), fmt, ap); 66 len = strlen(buf); 67 if(tfd >= 0) write(tfd, buf, len); 68 } 69 70 if (!in_tombstone_only) 71 __android_log_vprint(ANDROID_LOG_INFO, "DEBUG", fmt, ap); 72} 73 74#define LOG(fmt...) _LOG(-1, 0, fmt) 75#if 0 76#define XLOG(fmt...) _LOG(-1, 0, fmt) 77#else 78#define XLOG(fmt...) do {} while(0) 79#endif 80 81// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419 /system/lib/libcomposer.so 82// 012345678901234567890123456789012345678901234567890123456789 83// 0 1 2 3 4 5 84 85mapinfo *parse_maps_line(char *line) 86{ 87 mapinfo *mi; 88 int len = strlen(line); 89 90 if(len < 1) return 0; 91 line[--len] = 0; 92 93 if(len < 50) return 0; 94 if(line[20] != 'x') return 0; 95 96 mi = malloc(sizeof(mapinfo) + (len - 47)); 97 if(mi == 0) return 0; 98 99 mi->start = strtoul(line, 0, 16); 100 mi->end = strtoul(line + 9, 0, 16); 101 /* To be filled in parse_exidx_info if the mapped section starts with 102 * elf_header 103 */ 104 mi->exidx_start = mi->exidx_end = 0; 105 mi->next = 0; 106 strcpy(mi->name, line + 49); 107 108 return mi; 109} 110 111void dump_build_info(int tfd) 112{ 113 char fingerprint[PROPERTY_VALUE_MAX]; 114 115 property_get("ro.build.fingerprint", fingerprint, "unknown"); 116 117 _LOG(tfd, false, "Build fingerprint: '%s'\n", fingerprint); 118} 119 120 121void dump_stack_and_code(int tfd, int pid, mapinfo *map, 122 int unwind_depth, unsigned int sp_list[], 123 int frame0_pc_sane, bool at_fault) 124{ 125 unsigned int sp, pc, p, end, data; 126 struct pt_regs r; 127 int sp_depth; 128 bool only_in_tombstone = !at_fault; 129 char code_buffer[80]; 130 131 if(ptrace(PTRACE_GETREGS, pid, 0, &r)) return; 132 sp = r.ARM_sp; 133 pc = r.ARM_pc; 134 135 /* Died because calling the weeds - dump 136 * the code around the PC in the next frame instead. 137 */ 138 if (frame0_pc_sane == 0) { 139 pc = r.ARM_lr; 140 } 141 142 _LOG(tfd, only_in_tombstone, 143 "\ncode around %s:\n", frame0_pc_sane ? "pc" : "lr"); 144 145 end = p = pc & ~3; 146 p -= 16; 147 end += 16; 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 (frame0_pc_sane) { 167 _LOG(tfd, only_in_tombstone, "\ncode around lr:\n"); 168 169 end = p = r.ARM_lr & ~3; 170 p -= 16; 171 end += 16; 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 250void 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 268void 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 290const char *get_signame(int sig) 291{ 292 switch(sig) { 293 case SIGILL: return "SIGILL"; 294 case SIGABRT: return "SIGABRT"; 295 case SIGBUS: return "SIGBUS"; 296 case SIGFPE: return "SIGFPE"; 297 case SIGSEGV: return "SIGSEGV"; 298 case SIGSTKFLT: return "SIGSTKFLT"; 299 default: return "?"; 300 } 301} 302 303void dump_fault_addr(int tfd, int pid, int sig) 304{ 305 siginfo_t si; 306 307 memset(&si, 0, sizeof(si)); 308 if(ptrace(PTRACE_GETSIGINFO, pid, 0, &si)){ 309 _LOG(tfd, false, "cannot get siginfo: %s\n", strerror(errno)); 310 } else { 311 _LOG(tfd, false, "signal %d (%s), fault addr %08x\n", 312 sig, get_signame(sig), si.si_addr); 313 } 314} 315 316void dump_crash_banner(int tfd, unsigned pid, unsigned tid, int sig) 317{ 318 char data[1024]; 319 char *x = 0; 320 FILE *fp; 321 322 sprintf(data, "/proc/%d/cmdline", pid); 323 fp = fopen(data, "r"); 324 if(fp) { 325 x = fgets(data, 1024, fp); 326 fclose(fp); 327 } 328 329 _LOG(tfd, false, 330 "*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n"); 331 dump_build_info(tfd); 332 _LOG(tfd, false, "pid: %d, tid: %d >>> %s <<<\n", 333 pid, tid, x ? x : "UNKNOWN"); 334 335 if(sig) dump_fault_addr(tfd, tid, sig); 336} 337 338static void parse_exidx_info(mapinfo *milist, pid_t pid) 339{ 340 mapinfo *mi; 341 for (mi = milist; mi != NULL; mi = mi->next) { 342 Elf32_Ehdr ehdr; 343 344 memset(&ehdr, 0, sizeof(Elf32_Ehdr)); 345 /* Read in sizeof(Elf32_Ehdr) worth of data from the beginning of 346 * mapped section. 347 */ 348 get_remote_struct(pid, (void *) (mi->start), &ehdr, 349 sizeof(Elf32_Ehdr)); 350 /* Check if it has the matching magic words */ 351 if (IS_ELF(ehdr)) { 352 Elf32_Phdr phdr; 353 Elf32_Phdr *ptr; 354 int i; 355 356 ptr = (Elf32_Phdr *) (mi->start + ehdr.e_phoff); 357 for (i = 0; i < ehdr.e_phnum; i++) { 358 /* Parse the program header */ 359 get_remote_struct(pid, (char *) ptr+i, &phdr, 360 sizeof(Elf32_Phdr)); 361 /* Found a EXIDX segment? */ 362 if (phdr.p_type == PT_ARM_EXIDX) { 363 mi->exidx_start = mi->start + phdr.p_offset; 364 mi->exidx_end = mi->exidx_start + phdr.p_filesz; 365 break; 366 } 367 } 368 } 369 } 370} 371 372void dump_crash_report(int tfd, unsigned pid, unsigned tid, bool at_fault) 373{ 374 char data[1024]; 375 FILE *fp; 376 mapinfo *milist = 0; 377 unsigned int sp_list[STACK_CONTENT_DEPTH]; 378 int stack_depth; 379 int frame0_pc_sane = 1; 380 381 if (!at_fault) { 382 _LOG(tfd, true, 383 "--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---\n"); 384 _LOG(tfd, true, "pid: %d, tid: %d\n", pid, tid); 385 } 386 387 dump_registers(tfd, tid, at_fault); 388 389 /* Clear stack pointer records */ 390 memset(sp_list, 0, sizeof(sp_list)); 391 392 sprintf(data, "/proc/%d/maps", pid); 393 fp = fopen(data, "r"); 394 if(fp) { 395 while(fgets(data, 1024, fp)) { 396 mapinfo *mi = parse_maps_line(data); 397 if(mi) { 398 mi->next = milist; 399 milist = mi; 400 } 401 } 402 fclose(fp); 403 } 404 405 parse_exidx_info(milist, tid); 406 407 /* If stack unwinder fails, use the default solution to dump the stack 408 * content. 409 */ 410 stack_depth = unwind_backtrace_with_ptrace(tfd, tid, milist, sp_list, 411 &frame0_pc_sane, at_fault); 412 413 /* The stack unwinder should at least unwind two levels of stack. If less 414 * level is seen we make sure at lease pc and lr are dumped. 415 */ 416 if (stack_depth < 2) { 417 dump_pc_and_lr(tfd, tid, milist, stack_depth, at_fault); 418 } 419 420 dump_stack_and_code(tfd, tid, milist, stack_depth, sp_list, frame0_pc_sane, 421 at_fault); 422 423 while(milist) { 424 mapinfo *next = milist->next; 425 free(milist); 426 milist = next; 427 } 428} 429 430#define MAX_TOMBSTONES 10 431 432#define typecheck(x,y) { \ 433 typeof(x) __dummy1; \ 434 typeof(y) __dummy2; \ 435 (void)(&__dummy1 == &__dummy2); } 436 437#define TOMBSTONE_DIR "/data/tombstones" 438 439/* 440 * find_and_open_tombstone - find an available tombstone slot, if any, of the 441 * form tombstone_XX where XX is 00 to MAX_TOMBSTONES-1, inclusive. If no 442 * file is available, we reuse the least-recently-modified file. 443 */ 444static int find_and_open_tombstone(void) 445{ 446 unsigned long mtime = ULONG_MAX; 447 struct stat sb; 448 char path[128]; 449 int fd, i, oldest = 0; 450 451 /* 452 * XXX: Our stat.st_mtime isn't time_t. If it changes, as it probably ought 453 * to, our logic breaks. This check will generate a warning if that happens. 454 */ 455 typecheck(mtime, sb.st_mtime); 456 457 /* 458 * In a single wolf-like pass, find an available slot and, in case none 459 * exist, find and record the least-recently-modified file. 460 */ 461 for (i = 0; i < MAX_TOMBSTONES; i++) { 462 snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", i); 463 464 if (!stat(path, &sb)) { 465 if (sb.st_mtime < mtime) { 466 oldest = i; 467 mtime = sb.st_mtime; 468 } 469 continue; 470 } 471 if (errno != ENOENT) 472 continue; 473 474 fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0600); 475 if (fd < 0) 476 continue; /* raced ? */ 477 478 fchown(fd, AID_SYSTEM, AID_SYSTEM); 479 return fd; 480 } 481 482 /* we didn't find an available file, so we clobber the oldest one */ 483 snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", oldest); 484 fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600); 485 fchown(fd, AID_SYSTEM, AID_SYSTEM); 486 487 return fd; 488} 489 490/* Return true if some thread is not detached cleanly */ 491static bool dump_sibling_thread_report(int tfd, unsigned pid, unsigned tid) 492{ 493 char task_path[1024]; 494 495 sprintf(task_path, "/proc/%d/task", pid); 496 DIR *d; 497 struct dirent *de; 498 int need_cleanup = 0; 499 500 d = opendir(task_path); 501 /* Bail early if cannot open the task directory */ 502 if (d == NULL) { 503 XLOG("Cannot open /proc/%d/task\n", pid); 504 return false; 505 } 506 while ((de = readdir(d)) != NULL) { 507 unsigned new_tid; 508 /* Ignore "." and ".." */ 509 if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) 510 continue; 511 new_tid = atoi(de->d_name); 512 /* The main thread at fault has been handled individually */ 513 if (new_tid == tid) 514 continue; 515 516 /* Skip this thread if cannot ptrace it */ 517 if (ptrace(PTRACE_ATTACH, new_tid, 0, 0) < 0) 518 continue; 519 520 dump_crash_report(tfd, pid, new_tid, false); 521 need_cleanup |= ptrace(PTRACE_DETACH, new_tid, 0, 0); 522 } 523 closedir(d); 524 return need_cleanup != 0; 525} 526 527/* Return true if some thread is not detached cleanly */ 528static bool engrave_tombstone(unsigned pid, unsigned tid, int debug_uid, 529 int signal) 530{ 531 int fd; 532 bool need_cleanup = false; 533 534 mkdir(TOMBSTONE_DIR, 0755); 535 chown(TOMBSTONE_DIR, AID_SYSTEM, AID_SYSTEM); 536 537 fd = find_and_open_tombstone(); 538 if (fd < 0) 539 return need_cleanup; 540 541 dump_crash_banner(fd, pid, tid, signal); 542 dump_crash_report(fd, pid, tid, true); 543 /* 544 * If the user has requested to attach gdb, don't collect the per-thread 545 * information as it increases the chance to lose track of the process. 546 */ 547 if ((signed)pid > debug_uid) { 548 need_cleanup = dump_sibling_thread_report(fd, pid, tid); 549 } 550 551 close(fd); 552 return need_cleanup; 553} 554 555static int 556write_string(const char* file, const char* string) 557{ 558 int len; 559 int fd; 560 ssize_t amt; 561 fd = open(file, O_RDWR); 562 len = strlen(string); 563 if (fd < 0) 564 return -errno; 565 amt = write(fd, string, len); 566 close(fd); 567 return amt >= 0 ? 0 : -errno; 568} 569 570static 571void init_debug_led(void) 572{ 573 // trout leds 574 write_string("/sys/class/leds/red/brightness", "0"); 575 write_string("/sys/class/leds/green/brightness", "0"); 576 write_string("/sys/class/leds/blue/brightness", "0"); 577 write_string("/sys/class/leds/red/device/blink", "0"); 578 // sardine leds 579 write_string("/sys/class/leds/left/cadence", "0,0"); 580} 581 582static 583void enable_debug_led(void) 584{ 585 // trout leds 586 write_string("/sys/class/leds/red/brightness", "255"); 587 // sardine leds 588 write_string("/sys/class/leds/left/cadence", "1,0"); 589} 590 591static 592void disable_debug_led(void) 593{ 594 // trout leds 595 write_string("/sys/class/leds/red/brightness", "0"); 596 // sardine leds 597 write_string("/sys/class/leds/left/cadence", "0,0"); 598} 599 600extern int init_getevent(); 601extern void uninit_getevent(); 602extern int get_event(struct input_event* event, int timeout); 603 604static void wait_for_user_action(unsigned tid, struct ucred* cr) 605{ 606 (void)tid; 607 /* First log a helpful message */ 608 LOG( "********************************************************\n" 609 "* Process %d has been suspended while crashing. To\n" 610 "* attach gdbserver for a gdb connection on port 5039:\n" 611 "*\n" 612 "* adb shell gdbserver :5039 --attach %d &\n" 613 "*\n" 614 "* Press HOME key to let the process continue crashing.\n" 615 "********************************************************\n", 616 cr->pid, cr->pid); 617 618 /* wait for HOME key (TODO: something useful for devices w/o HOME key) */ 619 if (init_getevent() == 0) { 620 int ms = 1200 / 10; 621 int dit = 1; 622 int dah = 3*dit; 623 int _ = -dit; 624 int ___ = 3*_; 625 int _______ = 7*_; 626 const signed char codes[] = { 627 dit,_,dit,_,dit,___,dah,_,dah,_,dah,___,dit,_,dit,_,dit,_______ 628 }; 629 size_t s = 0; 630 struct input_event e; 631 int home = 0; 632 init_debug_led(); 633 enable_debug_led(); 634 do { 635 int timeout = abs((int)(codes[s])) * ms; 636 int res = get_event(&e, timeout); 637 if (res == 0) { 638 if (e.type==EV_KEY && e.code==KEY_HOME && e.value==0) 639 home = 1; 640 } else if (res == 1) { 641 if (++s >= sizeof(codes)/sizeof(*codes)) 642 s = 0; 643 if (codes[s] > 0) { 644 enable_debug_led(); 645 } else { 646 disable_debug_led(); 647 } 648 } 649 } while (!home); 650 uninit_getevent(); 651 } 652 653 /* don't forget to turn debug led off */ 654 disable_debug_led(); 655 656 /* close filedescriptor */ 657 LOG("debuggerd resuming process %d", cr->pid); 658 } 659 660static void handle_crashing_process(int fd) 661{ 662 char buf[64]; 663 struct stat s; 664 unsigned tid; 665 struct ucred cr; 666 int n, len, status; 667 int tid_attach_status = -1; 668 unsigned retry = 30; 669 bool need_cleanup = false; 670 671 char value[PROPERTY_VALUE_MAX]; 672 property_get("debug.db.uid", value, "-1"); 673 int debug_uid = atoi(value); 674 675 XLOG("handle_crashing_process(%d)\n", fd); 676 677 len = sizeof(cr); 678 n = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &len); 679 if(n != 0) { 680 LOG("cannot get credentials\n"); 681 goto done; 682 } 683 684 XLOG("reading tid\n"); 685 fcntl(fd, F_SETFL, O_NONBLOCK); 686 while((n = read(fd, &tid, sizeof(unsigned))) != sizeof(unsigned)) { 687 if(errno == EINTR) continue; 688 if(errno == EWOULDBLOCK) { 689 if(retry-- > 0) { 690 usleep(100 * 1000); 691 continue; 692 } 693 LOG("timed out reading tid\n"); 694 goto done; 695 } 696 LOG("read failure? %s\n", strerror(errno)); 697 goto done; 698 } 699 700 sprintf(buf,"/proc/%d/task/%d", cr.pid, tid); 701 if(stat(buf, &s)) { 702 LOG("tid %d does not exist in pid %d. ignoring debug request\n", 703 tid, cr.pid); 704 close(fd); 705 return; 706 } 707 708 XLOG("BOOM: pid=%d uid=%d gid=%d tid=%d\n", cr.pid, cr.uid, cr.gid, tid); 709 710 tid_attach_status = ptrace(PTRACE_ATTACH, tid, 0, 0); 711 if(tid_attach_status < 0) { 712 LOG("ptrace attach failed: %s\n", strerror(errno)); 713 goto done; 714 } 715 716 close(fd); 717 fd = -1; 718 719 for(;;) { 720 n = waitpid(tid, &status, __WALL); 721 722 if(n < 0) { 723 if(errno == EAGAIN) continue; 724 LOG("waitpid failed: %s\n", strerror(errno)); 725 goto done; 726 } 727 728 XLOG("waitpid: n=%d status=%08x\n", n, status); 729 730 if(WIFSTOPPED(status)){ 731 n = WSTOPSIG(status); 732 switch(n) { 733 case SIGSTOP: 734 XLOG("stopped -- continuing\n"); 735 n = ptrace(PTRACE_CONT, tid, 0, 0); 736 if(n) { 737 LOG("ptrace failed: %s\n", strerror(errno)); 738 goto done; 739 } 740 continue; 741 742 case SIGILL: 743 case SIGABRT: 744 case SIGBUS: 745 case SIGFPE: 746 case SIGSEGV: 747 case SIGSTKFLT: { 748 XLOG("stopped -- fatal signal\n"); 749 need_cleanup = engrave_tombstone(cr.pid, tid, debug_uid, n); 750 kill(tid, SIGSTOP); 751 goto done; 752 } 753 754 default: 755 XLOG("stopped -- unexpected signal\n"); 756 goto done; 757 } 758 } else { 759 XLOG("unexpected waitpid response\n"); 760 goto done; 761 } 762 } 763 764done: 765 XLOG("detaching\n"); 766 767 /* stop the process so we can debug */ 768 kill(cr.pid, SIGSTOP); 769 770 /* 771 * If a thread has been attached by ptrace, make sure it is detached 772 * successfully otherwise we will get a zombie. 773 */ 774 if (tid_attach_status == 0) { 775 int detach_status; 776 /* detach so we can attach gdbserver */ 777 detach_status = ptrace(PTRACE_DETACH, tid, 0, 0); 778 need_cleanup |= (detach_status != 0); 779 } 780 781 /* 782 * if debug.db.uid is set, its value indicates if we should wait 783 * for user action for the crashing process. 784 * in this case, we log a message and turn the debug LED on 785 * waiting for a gdb connection (for instance) 786 */ 787 788 if ((signed)cr.uid <= debug_uid) { 789 wait_for_user_action(tid, &cr); 790 } 791 792 /* resume stopped process (so it can crash in peace) */ 793 kill(cr.pid, SIGCONT); 794 795 if (need_cleanup) { 796 LOG("debuggerd committing suicide to free the zombie!\n"); 797 kill(getpid(), SIGKILL); 798 } 799 800 if(fd != -1) close(fd); 801} 802 803int main() 804{ 805 int s; 806 struct sigaction act; 807 808 logsocket = socket_local_client("logd", 809 ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_DGRAM); 810 if(logsocket < 0) { 811 logsocket = -1; 812 } else { 813 fcntl(logsocket, F_SETFD, FD_CLOEXEC); 814 } 815 816 act.sa_handler = SIG_DFL; 817 sigemptyset(&act.sa_mask); 818 sigaddset(&act.sa_mask,SIGCHLD); 819 act.sa_flags = SA_NOCLDWAIT; 820 sigaction(SIGCHLD, &act, 0); 821 822 s = socket_local_server("android:debuggerd", 823 ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM); 824 if(s < 0) return -1; 825 fcntl(s, F_SETFD, FD_CLOEXEC); 826 827 LOG("debuggerd: " __DATE__ " " __TIME__ "\n"); 828 829 for(;;) { 830 struct sockaddr addr; 831 socklen_t alen; 832 int fd; 833 834 alen = sizeof(addr); 835 fd = accept(s, &addr, &alen); 836 if(fd < 0) continue; 837 838 fcntl(fd, F_SETFD, FD_CLOEXEC); 839 840 handle_crashing_process(fd); 841 } 842 return 0; 843} 844