debuggerd.c revision 44659e90fe8df25c71195936eabe0cc9158c18a6
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 <errno.h> 20#include <signal.h> 21#include <pthread.h> 22#include <stdarg.h> 23#include <fcntl.h> 24#include <sys/types.h> 25#include <dirent.h> 26 27#include <sys/ptrace.h> 28#include <sys/wait.h> 29#include <sys/exec_elf.h> 30#include <sys/stat.h> 31 32#include <cutils/sockets.h> 33#include <cutils/logd.h> 34#include <cutils/properties.h> 35 36#include <linux/input.h> 37 38#include <private/android_filesystem_config.h> 39 40#include "debuggerd.h" 41#include "utility.h" 42 43#define ANDROID_LOG_INFO 4 44 45/* Log information onto the tombstone */ 46void _LOG(int tfd, bool in_tombstone_only, const char *fmt, ...) 47{ 48 char buf[512]; 49 50 va_list ap; 51 va_start(ap, fmt); 52 53 if (tfd >= 0) { 54 int len; 55 vsnprintf(buf, sizeof(buf), fmt, ap); 56 len = strlen(buf); 57 if(tfd >= 0) write(tfd, buf, len); 58 } 59 60 if (!in_tombstone_only) 61 __android_log_vprint(ANDROID_LOG_INFO, "DEBUG", fmt, ap); 62} 63 64// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419 /system/lib/libcomposer.so 65// 012345678901234567890123456789012345678901234567890123456789 66// 0 1 2 3 4 5 67 68mapinfo *parse_maps_line(char *line) 69{ 70 mapinfo *mi; 71 int len = strlen(line); 72 73 if(len < 1) return 0; 74 line[--len] = 0; 75 76 if(len < 50) return 0; 77 if(line[20] != 'x') return 0; 78 79 mi = malloc(sizeof(mapinfo) + (len - 47)); 80 if(mi == 0) return 0; 81 82 mi->start = strtoul(line, 0, 16); 83 mi->end = strtoul(line + 9, 0, 16); 84 /* To be filled in parse_elf_info if the mapped section starts with 85 * elf_header 86 */ 87 mi->exidx_start = mi->exidx_end = 0; 88 mi->symbols = 0; 89 mi->next = 0; 90 strcpy(mi->name, line + 49); 91 92 return mi; 93} 94 95void dump_build_info(int tfd) 96{ 97 char fingerprint[PROPERTY_VALUE_MAX]; 98 99 property_get("ro.build.fingerprint", fingerprint, "unknown"); 100 101 _LOG(tfd, false, "Build fingerprint: '%s'\n", fingerprint); 102} 103 104const char *get_signame(int sig) 105{ 106 switch(sig) { 107 case SIGILL: return "SIGILL"; 108 case SIGABRT: return "SIGABRT"; 109 case SIGBUS: return "SIGBUS"; 110 case SIGFPE: return "SIGFPE"; 111 case SIGSEGV: return "SIGSEGV"; 112 case SIGSTKFLT: return "SIGSTKFLT"; 113 default: return "?"; 114 } 115} 116 117const char *get_sigcode(int signo, int code) 118{ 119 switch (signo) { 120 case SIGILL: 121 switch (code) { 122 case ILL_ILLOPC: return "ILL_ILLOPC"; 123 case ILL_ILLOPN: return "ILL_ILLOPN"; 124 case ILL_ILLADR: return "ILL_ILLADR"; 125 case ILL_ILLTRP: return "ILL_ILLTRP"; 126 case ILL_PRVOPC: return "ILL_PRVOPC"; 127 case ILL_PRVREG: return "ILL_PRVREG"; 128 case ILL_COPROC: return "ILL_COPROC"; 129 case ILL_BADSTK: return "ILL_BADSTK"; 130 } 131 break; 132 case SIGBUS: 133 switch (code) { 134 case BUS_ADRALN: return "BUS_ADRALN"; 135 case BUS_ADRERR: return "BUS_ADRERR"; 136 case BUS_OBJERR: return "BUS_OBJERR"; 137 } 138 break; 139 case SIGFPE: 140 switch (code) { 141 case FPE_INTDIV: return "FPE_INTDIV"; 142 case FPE_INTOVF: return "FPE_INTOVF"; 143 case FPE_FLTDIV: return "FPE_FLTDIV"; 144 case FPE_FLTOVF: return "FPE_FLTOVF"; 145 case FPE_FLTUND: return "FPE_FLTUND"; 146 case FPE_FLTRES: return "FPE_FLTRES"; 147 case FPE_FLTINV: return "FPE_FLTINV"; 148 case FPE_FLTSUB: return "FPE_FLTSUB"; 149 } 150 break; 151 case SIGSEGV: 152 switch (code) { 153 case SEGV_MAPERR: return "SEGV_MAPERR"; 154 case SEGV_ACCERR: return "SEGV_ACCERR"; 155 } 156 break; 157 } 158 return "?"; 159} 160 161void dump_fault_addr(int tfd, int pid, int sig) 162{ 163 siginfo_t si; 164 165 memset(&si, 0, sizeof(si)); 166 if(ptrace(PTRACE_GETSIGINFO, pid, 0, &si)){ 167 _LOG(tfd, false, "cannot get siginfo: %s\n", strerror(errno)); 168 } else { 169 _LOG(tfd, false, "signal %d (%s), code %d (%s), fault addr %08x\n", 170 sig, get_signame(sig), 171 si.si_code, get_sigcode(sig, si.si_code), 172 si.si_addr); 173 } 174} 175 176void dump_crash_banner(int tfd, unsigned pid, unsigned tid, int sig) 177{ 178 char data[1024]; 179 char *x = 0; 180 FILE *fp; 181 182 sprintf(data, "/proc/%d/cmdline", pid); 183 fp = fopen(data, "r"); 184 if(fp) { 185 x = fgets(data, 1024, fp); 186 fclose(fp); 187 } 188 189 _LOG(tfd, false, 190 "*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n"); 191 dump_build_info(tfd); 192 _LOG(tfd, false, "pid: %d, tid: %d >>> %s <<<\n", 193 pid, tid, x ? x : "UNKNOWN"); 194 195 if(sig) dump_fault_addr(tfd, tid, sig); 196} 197 198static void parse_elf_info(mapinfo *milist, pid_t pid) 199{ 200 mapinfo *mi; 201 for (mi = milist; mi != NULL; mi = mi->next) { 202 Elf32_Ehdr ehdr; 203 204 memset(&ehdr, 0, sizeof(Elf32_Ehdr)); 205 /* Read in sizeof(Elf32_Ehdr) worth of data from the beginning of 206 * mapped section. 207 */ 208 get_remote_struct(pid, (void *) (mi->start), &ehdr, 209 sizeof(Elf32_Ehdr)); 210 /* Check if it has the matching magic words */ 211 if (IS_ELF(ehdr)) { 212 Elf32_Phdr phdr; 213 Elf32_Phdr *ptr; 214 int i; 215 216 ptr = (Elf32_Phdr *) (mi->start + ehdr.e_phoff); 217 for (i = 0; i < ehdr.e_phnum; i++) { 218 /* Parse the program header */ 219 get_remote_struct(pid, (char *) (ptr+i), &phdr, 220 sizeof(Elf32_Phdr)); 221#ifdef __arm__ 222 /* Found a EXIDX segment? */ 223 if (phdr.p_type == PT_ARM_EXIDX) { 224 mi->exidx_start = mi->start + phdr.p_offset; 225 mi->exidx_end = mi->exidx_start + phdr.p_filesz; 226 break; 227 } 228#endif 229 } 230 231 /* Try to load symbols from this file */ 232 mi->symbols = symbol_table_create(mi->name); 233 } 234 } 235} 236 237void dump_crash_report(int tfd, unsigned pid, unsigned tid, bool at_fault) 238{ 239 char data[1024]; 240 FILE *fp; 241 mapinfo *milist = 0; 242 unsigned int sp_list[STACK_CONTENT_DEPTH]; 243 int stack_depth; 244#ifdef __arm__ 245 int frame0_pc_sane = 1; 246#endif 247 248 if (!at_fault) { 249 _LOG(tfd, true, 250 "--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---\n"); 251 _LOG(tfd, true, "pid: %d, tid: %d\n", pid, tid); 252 } 253 254 dump_registers(tfd, tid, at_fault); 255 256 /* Clear stack pointer records */ 257 memset(sp_list, 0, sizeof(sp_list)); 258 259 sprintf(data, "/proc/%d/maps", pid); 260 fp = fopen(data, "r"); 261 if(fp) { 262 while(fgets(data, 1024, fp)) { 263 mapinfo *mi = parse_maps_line(data); 264 if(mi) { 265 mi->next = milist; 266 milist = mi; 267 } 268 } 269 fclose(fp); 270 } 271 272 parse_elf_info(milist, tid); 273 274#if __arm__ 275 /* If stack unwinder fails, use the default solution to dump the stack 276 * content. 277 */ 278 stack_depth = unwind_backtrace_with_ptrace(tfd, tid, milist, sp_list, 279 &frame0_pc_sane, at_fault); 280 281 /* The stack unwinder should at least unwind two levels of stack. If less 282 * level is seen we make sure at lease pc and lr are dumped. 283 */ 284 if (stack_depth < 2) { 285 dump_pc_and_lr(tfd, tid, milist, stack_depth, at_fault); 286 } 287 288 dump_stack_and_code(tfd, tid, milist, stack_depth, sp_list, at_fault); 289#elif __i386__ 290 /* If stack unwinder fails, use the default solution to dump the stack 291 * content. 292 */ 293 stack_depth = unwind_backtrace_with_ptrace_x86(tfd, tid, milist,at_fault); 294#else 295#error "Unsupported architecture" 296#endif 297 298 while(milist) { 299 mapinfo *next = milist->next; 300 symbol_table_free(milist->symbols); 301 free(milist); 302 milist = next; 303 } 304} 305 306#define MAX_TOMBSTONES 10 307 308#define typecheck(x,y) { \ 309 typeof(x) __dummy1; \ 310 typeof(y) __dummy2; \ 311 (void)(&__dummy1 == &__dummy2); } 312 313#define TOMBSTONE_DIR "/data/tombstones" 314 315/* 316 * find_and_open_tombstone - find an available tombstone slot, if any, of the 317 * form tombstone_XX where XX is 00 to MAX_TOMBSTONES-1, inclusive. If no 318 * file is available, we reuse the least-recently-modified file. 319 */ 320static int find_and_open_tombstone(void) 321{ 322 unsigned long mtime = ULONG_MAX; 323 struct stat sb; 324 char path[128]; 325 int fd, i, oldest = 0; 326 327 /* 328 * XXX: Our stat.st_mtime isn't time_t. If it changes, as it probably ought 329 * to, our logic breaks. This check will generate a warning if that happens. 330 */ 331 typecheck(mtime, sb.st_mtime); 332 333 /* 334 * In a single wolf-like pass, find an available slot and, in case none 335 * exist, find and record the least-recently-modified file. 336 */ 337 for (i = 0; i < MAX_TOMBSTONES; i++) { 338 snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", i); 339 340 if (!stat(path, &sb)) { 341 if (sb.st_mtime < mtime) { 342 oldest = i; 343 mtime = sb.st_mtime; 344 } 345 continue; 346 } 347 if (errno != ENOENT) 348 continue; 349 350 fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0600); 351 if (fd < 0) 352 continue; /* raced ? */ 353 354 fchown(fd, AID_SYSTEM, AID_SYSTEM); 355 return fd; 356 } 357 358 /* we didn't find an available file, so we clobber the oldest one */ 359 snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", oldest); 360 fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600); 361 fchown(fd, AID_SYSTEM, AID_SYSTEM); 362 363 return fd; 364} 365 366/* Return true if some thread is not detached cleanly */ 367static bool dump_sibling_thread_report(int tfd, unsigned pid, unsigned tid) 368{ 369 char task_path[1024]; 370 371 sprintf(task_path, "/proc/%d/task", pid); 372 DIR *d; 373 struct dirent *de; 374 int need_cleanup = 0; 375 376 d = opendir(task_path); 377 /* Bail early if cannot open the task directory */ 378 if (d == NULL) { 379 XLOG("Cannot open /proc/%d/task\n", pid); 380 return false; 381 } 382 while ((de = readdir(d)) != NULL) { 383 unsigned new_tid; 384 /* Ignore "." and ".." */ 385 if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) 386 continue; 387 new_tid = atoi(de->d_name); 388 /* The main thread at fault has been handled individually */ 389 if (new_tid == tid) 390 continue; 391 392 /* Skip this thread if cannot ptrace it */ 393 if (ptrace(PTRACE_ATTACH, new_tid, 0, 0) < 0) 394 continue; 395 396 dump_crash_report(tfd, pid, new_tid, false); 397 need_cleanup |= ptrace(PTRACE_DETACH, new_tid, 0, 0); 398 } 399 closedir(d); 400 return need_cleanup != 0; 401} 402 403/* Return true if some thread is not detached cleanly */ 404static bool engrave_tombstone(unsigned pid, unsigned tid, int debug_uid, 405 int signal) 406{ 407 int fd; 408 bool need_cleanup = false; 409 410 mkdir(TOMBSTONE_DIR, 0755); 411 chown(TOMBSTONE_DIR, AID_SYSTEM, AID_SYSTEM); 412 413 fd = find_and_open_tombstone(); 414 if (fd < 0) 415 return need_cleanup; 416 417 dump_crash_banner(fd, pid, tid, signal); 418 dump_crash_report(fd, pid, tid, true); 419 /* 420 * If the user has requested to attach gdb, don't collect the per-thread 421 * information as it increases the chance to lose track of the process. 422 */ 423 if ((signed)pid > debug_uid) { 424 need_cleanup = dump_sibling_thread_report(fd, pid, tid); 425 } 426 427 close(fd); 428 return need_cleanup; 429} 430 431static int 432write_string(const char* file, const char* string) 433{ 434 int len; 435 int fd; 436 ssize_t amt; 437 fd = open(file, O_RDWR); 438 len = strlen(string); 439 if (fd < 0) 440 return -errno; 441 amt = write(fd, string, len); 442 close(fd); 443 return amt >= 0 ? 0 : -errno; 444} 445 446static 447void init_debug_led(void) 448{ 449 // trout leds 450 write_string("/sys/class/leds/red/brightness", "0"); 451 write_string("/sys/class/leds/green/brightness", "0"); 452 write_string("/sys/class/leds/blue/brightness", "0"); 453 write_string("/sys/class/leds/red/device/blink", "0"); 454 // sardine leds 455 write_string("/sys/class/leds/left/cadence", "0,0"); 456} 457 458static 459void enable_debug_led(void) 460{ 461 // trout leds 462 write_string("/sys/class/leds/red/brightness", "255"); 463 // sardine leds 464 write_string("/sys/class/leds/left/cadence", "1,0"); 465} 466 467static 468void disable_debug_led(void) 469{ 470 // trout leds 471 write_string("/sys/class/leds/red/brightness", "0"); 472 // sardine leds 473 write_string("/sys/class/leds/left/cadence", "0,0"); 474} 475 476extern int init_getevent(); 477extern void uninit_getevent(); 478extern int get_event(struct input_event* event, int timeout); 479 480static void wait_for_user_action(unsigned tid, struct ucred* cr) 481{ 482 (void)tid; 483 /* First log a helpful message */ 484 LOG( "********************************************************\n" 485 "* Process %d has been suspended while crashing. To\n" 486 "* attach gdbserver for a gdb connection on port 5039:\n" 487 "*\n" 488 "* adb shell gdbserver :5039 --attach %d &\n" 489 "*\n" 490 "* Press HOME key to let the process continue crashing.\n" 491 "********************************************************\n", 492 cr->pid, cr->pid); 493 494 /* wait for HOME key (TODO: something useful for devices w/o HOME key) */ 495 if (init_getevent() == 0) { 496 int ms = 1200 / 10; 497 int dit = 1; 498 int dah = 3*dit; 499 int _ = -dit; 500 int ___ = 3*_; 501 int _______ = 7*_; 502 const signed char codes[] = { 503 dit,_,dit,_,dit,___,dah,_,dah,_,dah,___,dit,_,dit,_,dit,_______ 504 }; 505 size_t s = 0; 506 struct input_event e; 507 int home = 0; 508 init_debug_led(); 509 enable_debug_led(); 510 do { 511 int timeout = abs((int)(codes[s])) * ms; 512 int res = get_event(&e, timeout); 513 if (res == 0) { 514 if (e.type==EV_KEY && e.code==KEY_HOME && e.value==0) 515 home = 1; 516 } else if (res == 1) { 517 if (++s >= sizeof(codes)/sizeof(*codes)) 518 s = 0; 519 if (codes[s] > 0) { 520 enable_debug_led(); 521 } else { 522 disable_debug_led(); 523 } 524 } 525 } while (!home); 526 uninit_getevent(); 527 } 528 529 /* don't forget to turn debug led off */ 530 disable_debug_led(); 531 532 /* close filedescriptor */ 533 LOG("debuggerd resuming process %d", cr->pid); 534 } 535 536static void handle_crashing_process(int fd) 537{ 538 char buf[64]; 539 struct stat s; 540 unsigned tid; 541 struct ucred cr; 542 int n, len, status; 543 int tid_attach_status = -1; 544 unsigned retry = 30; 545 bool need_cleanup = false; 546 547 char value[PROPERTY_VALUE_MAX]; 548 property_get("debug.db.uid", value, "-1"); 549 int debug_uid = atoi(value); 550 551 XLOG("handle_crashing_process(%d)\n", fd); 552 553 len = sizeof(cr); 554 n = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &len); 555 if(n != 0) { 556 LOG("cannot get credentials\n"); 557 goto done; 558 } 559 560 XLOG("reading tid\n"); 561 fcntl(fd, F_SETFL, O_NONBLOCK); 562 while((n = read(fd, &tid, sizeof(unsigned))) != sizeof(unsigned)) { 563 if(errno == EINTR) continue; 564 if(errno == EWOULDBLOCK) { 565 if(retry-- > 0) { 566 usleep(100 * 1000); 567 continue; 568 } 569 LOG("timed out reading tid\n"); 570 goto done; 571 } 572 LOG("read failure? %s\n", strerror(errno)); 573 goto done; 574 } 575 576 sprintf(buf,"/proc/%d/task/%d", cr.pid, tid); 577 if(stat(buf, &s)) { 578 LOG("tid %d does not exist in pid %d. ignoring debug request\n", 579 tid, cr.pid); 580 close(fd); 581 return; 582 } 583 584 XLOG("BOOM: pid=%d uid=%d gid=%d tid=%d\n", cr.pid, cr.uid, cr.gid, tid); 585 586 tid_attach_status = ptrace(PTRACE_ATTACH, tid, 0, 0); 587 if(tid_attach_status < 0) { 588 LOG("ptrace attach failed: %s\n", strerror(errno)); 589 goto done; 590 } 591 592 close(fd); 593 fd = -1; 594 595 for(;;) { 596 n = waitpid(tid, &status, __WALL); 597 598 if(n < 0) { 599 if(errno == EAGAIN) continue; 600 LOG("waitpid failed: %s\n", strerror(errno)); 601 goto done; 602 } 603 604 XLOG("waitpid: n=%d status=%08x\n", n, status); 605 606 if(WIFSTOPPED(status)){ 607 n = WSTOPSIG(status); 608 switch(n) { 609 case SIGSTOP: 610 XLOG("stopped -- continuing\n"); 611 n = ptrace(PTRACE_CONT, tid, 0, 0); 612 if(n) { 613 LOG("ptrace failed: %s\n", strerror(errno)); 614 goto done; 615 } 616 continue; 617 618 case SIGILL: 619 case SIGABRT: 620 case SIGBUS: 621 case SIGFPE: 622 case SIGSEGV: 623 case SIGSTKFLT: { 624 XLOG("stopped -- fatal signal\n"); 625 need_cleanup = engrave_tombstone(cr.pid, tid, debug_uid, n); 626 kill(tid, SIGSTOP); 627 goto done; 628 } 629 630 default: 631 XLOG("stopped -- unexpected signal\n"); 632 goto done; 633 } 634 } else { 635 XLOG("unexpected waitpid response\n"); 636 goto done; 637 } 638 } 639 640done: 641 XLOG("detaching\n"); 642 643 /* stop the process so we can debug */ 644 kill(cr.pid, SIGSTOP); 645 646 /* 647 * If a thread has been attached by ptrace, make sure it is detached 648 * successfully otherwise we will get a zombie. 649 */ 650 if (tid_attach_status == 0) { 651 int detach_status; 652 /* detach so we can attach gdbserver */ 653 detach_status = ptrace(PTRACE_DETACH, tid, 0, 0); 654 need_cleanup |= (detach_status != 0); 655 } 656 657 /* 658 * if debug.db.uid is set, its value indicates if we should wait 659 * for user action for the crashing process. 660 * in this case, we log a message and turn the debug LED on 661 * waiting for a gdb connection (for instance) 662 */ 663 664 if ((signed)cr.uid <= debug_uid) { 665 wait_for_user_action(tid, &cr); 666 } 667 668 /* resume stopped process (so it can crash in peace) */ 669 kill(cr.pid, SIGCONT); 670 671 if (need_cleanup) { 672 LOG("debuggerd committing suicide to free the zombie!\n"); 673 kill(getpid(), SIGKILL); 674 } 675 676 if(fd != -1) close(fd); 677} 678 679 680int main() 681{ 682 int s; 683 struct sigaction act; 684 int logsocket = -1; 685 686 logsocket = socket_local_client("logd", 687 ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_DGRAM); 688 if(logsocket < 0) { 689 logsocket = -1; 690 } else { 691 fcntl(logsocket, F_SETFD, FD_CLOEXEC); 692 } 693 694 act.sa_handler = SIG_DFL; 695 sigemptyset(&act.sa_mask); 696 sigaddset(&act.sa_mask,SIGCHLD); 697 act.sa_flags = SA_NOCLDWAIT; 698 sigaction(SIGCHLD, &act, 0); 699 700 s = socket_local_server("android:debuggerd", 701 ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM); 702 if(s < 0) return -1; 703 fcntl(s, F_SETFD, FD_CLOEXEC); 704 705 LOG("debuggerd: " __DATE__ " " __TIME__ "\n"); 706 707 for(;;) { 708 struct sockaddr addr; 709 socklen_t alen; 710 int fd; 711 712 alen = sizeof(addr); 713 fd = accept(s, &addr, &alen); 714 if(fd < 0) continue; 715 716 fcntl(fd, F_SETFD, FD_CLOEXEC); 717 718 handle_crashing_process(fd); 719 } 720 return 0; 721} 722