• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * Copyright (C) 2012-2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #define LOG_TAG "DEBUG"
18 
19 #include <dirent.h>
20 #include <errno.h>
21 #include <fcntl.h>
22 #include <inttypes.h>
23 #include <signal.h>
24 #include <stddef.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <time.h>
29 #include <sys/ptrace.h>
30 #include <sys/stat.h>
31 
32 #include <memory>
33 #include <string>
34 
35 #include <private/android_filesystem_config.h>
36 
37 #include <android-base/stringprintf.h>
38 #include <cutils/properties.h>
39 #include <log/log.h>
40 #include <log/logger.h>
41 #include <log/logprint.h>
42 
43 #include <backtrace/Backtrace.h>
44 #include <backtrace/BacktraceMap.h>
45 
46 #include <selinux/android.h>
47 
48 #include "backtrace.h"
49 #include "elf_utils.h"
50 #include "machine.h"
51 #include "tombstone.h"
52 
53 #define STACK_WORDS 16
54 
55 #define MAX_TOMBSTONES  10
56 #define TOMBSTONE_DIR   "/data/tombstones"
57 #define TOMBSTONE_TEMPLATE (TOMBSTONE_DIR"/tombstone_%02d")
58 
signal_has_si_addr(int sig)59 static bool signal_has_si_addr(int sig) {
60   switch (sig) {
61     case SIGBUS:
62     case SIGFPE:
63     case SIGILL:
64     case SIGSEGV:
65     case SIGTRAP:
66       return true;
67     default:
68       return false;
69   }
70 }
71 
get_signame(int sig)72 static const char* get_signame(int sig) {
73   switch(sig) {
74     case SIGABRT: return "SIGABRT";
75     case SIGBUS: return "SIGBUS";
76     case SIGFPE: return "SIGFPE";
77     case SIGILL: return "SIGILL";
78     case SIGSEGV: return "SIGSEGV";
79 #if defined(SIGSTKFLT)
80     case SIGSTKFLT: return "SIGSTKFLT";
81 #endif
82     case SIGSTOP: return "SIGSTOP";
83     case SIGTRAP: return "SIGTRAP";
84     default: return "?";
85   }
86 }
87 
get_sigcode(int signo,int code)88 static const char* get_sigcode(int signo, int code) {
89   // Try the signal-specific codes...
90   switch (signo) {
91     case SIGILL:
92       switch (code) {
93         case ILL_ILLOPC: return "ILL_ILLOPC";
94         case ILL_ILLOPN: return "ILL_ILLOPN";
95         case ILL_ILLADR: return "ILL_ILLADR";
96         case ILL_ILLTRP: return "ILL_ILLTRP";
97         case ILL_PRVOPC: return "ILL_PRVOPC";
98         case ILL_PRVREG: return "ILL_PRVREG";
99         case ILL_COPROC: return "ILL_COPROC";
100         case ILL_BADSTK: return "ILL_BADSTK";
101       }
102       static_assert(NSIGILL == ILL_BADSTK, "missing ILL_* si_code");
103       break;
104     case SIGBUS:
105       switch (code) {
106         case BUS_ADRALN: return "BUS_ADRALN";
107         case BUS_ADRERR: return "BUS_ADRERR";
108         case BUS_OBJERR: return "BUS_OBJERR";
109         case BUS_MCEERR_AR: return "BUS_MCEERR_AR";
110         case BUS_MCEERR_AO: return "BUS_MCEERR_AO";
111       }
112       static_assert(NSIGBUS == BUS_MCEERR_AO, "missing BUS_* si_code");
113       break;
114     case SIGFPE:
115       switch (code) {
116         case FPE_INTDIV: return "FPE_INTDIV";
117         case FPE_INTOVF: return "FPE_INTOVF";
118         case FPE_FLTDIV: return "FPE_FLTDIV";
119         case FPE_FLTOVF: return "FPE_FLTOVF";
120         case FPE_FLTUND: return "FPE_FLTUND";
121         case FPE_FLTRES: return "FPE_FLTRES";
122         case FPE_FLTINV: return "FPE_FLTINV";
123         case FPE_FLTSUB: return "FPE_FLTSUB";
124       }
125       static_assert(NSIGFPE == FPE_FLTSUB, "missing FPE_* si_code");
126       break;
127     case SIGSEGV:
128       switch (code) {
129         case SEGV_MAPERR: return "SEGV_MAPERR";
130         case SEGV_ACCERR: return "SEGV_ACCERR";
131 #if defined(SEGV_BNDERR)
132         case SEGV_BNDERR: return "SEGV_BNDERR";
133 #endif
134       }
135 #if defined(SEGV_BNDERR)
136       static_assert(NSIGSEGV == SEGV_BNDERR, "missing SEGV_* si_code");
137 #else
138       static_assert(NSIGSEGV == SEGV_ACCERR, "missing SEGV_* si_code");
139 #endif
140       break;
141     case SIGTRAP:
142       switch (code) {
143         case TRAP_BRKPT: return "TRAP_BRKPT";
144         case TRAP_TRACE: return "TRAP_TRACE";
145         case TRAP_BRANCH: return "TRAP_BRANCH";
146         case TRAP_HWBKPT: return "TRAP_HWBKPT";
147       }
148       static_assert(NSIGTRAP == TRAP_HWBKPT, "missing TRAP_* si_code");
149       break;
150   }
151   // Then the other codes...
152   switch (code) {
153     case SI_USER: return "SI_USER";
154     case SI_KERNEL: return "SI_KERNEL";
155     case SI_QUEUE: return "SI_QUEUE";
156     case SI_TIMER: return "SI_TIMER";
157     case SI_MESGQ: return "SI_MESGQ";
158     case SI_ASYNCIO: return "SI_ASYNCIO";
159     case SI_SIGIO: return "SI_SIGIO";
160     case SI_TKILL: return "SI_TKILL";
161     case SI_DETHREAD: return "SI_DETHREAD";
162   }
163   // Then give up...
164   return "?";
165 }
166 
dump_header_info(log_t * log)167 static void dump_header_info(log_t* log) {
168   char fingerprint[PROPERTY_VALUE_MAX];
169   char revision[PROPERTY_VALUE_MAX];
170 
171   property_get("ro.build.fingerprint", fingerprint, "unknown");
172   property_get("ro.revision", revision, "unknown");
173 
174   _LOG(log, logtype::HEADER, "Build fingerprint: '%s'\n", fingerprint);
175   _LOG(log, logtype::HEADER, "Revision: '%s'\n", revision);
176   _LOG(log, logtype::HEADER, "ABI: '%s'\n", ABI_STRING);
177 }
178 
dump_signal_info(log_t * log,pid_t tid,int signal,int si_code)179 static void dump_signal_info(log_t* log, pid_t tid, int signal, int si_code) {
180   siginfo_t si;
181   memset(&si, 0, sizeof(si));
182   if (ptrace(PTRACE_GETSIGINFO, tid, 0, &si) == -1) {
183     ALOGE("cannot get siginfo: %s\n", strerror(errno));
184     return;
185   }
186 
187   // bionic has to re-raise some signals, which overwrites the si_code with SI_TKILL.
188   si.si_code = si_code;
189 
190   char addr_desc[32]; // ", fault addr 0x1234"
191   if (signal_has_si_addr(signal)) {
192     snprintf(addr_desc, sizeof(addr_desc), "%p", si.si_addr);
193   } else {
194     snprintf(addr_desc, sizeof(addr_desc), "--------");
195   }
196 
197   _LOG(log, logtype::HEADER, "signal %d (%s), code %d (%s), fault addr %s\n",
198        signal, get_signame(signal), si.si_code, get_sigcode(signal, si.si_code), addr_desc);
199 }
200 
dump_thread_info(log_t * log,pid_t pid,pid_t tid)201 static void dump_thread_info(log_t* log, pid_t pid, pid_t tid) {
202   char path[64];
203   char threadnamebuf[1024];
204   char* threadname = nullptr;
205   FILE *fp;
206 
207   snprintf(path, sizeof(path), "/proc/%d/comm", tid);
208   if ((fp = fopen(path, "r"))) {
209     threadname = fgets(threadnamebuf, sizeof(threadnamebuf), fp);
210     fclose(fp);
211     if (threadname) {
212       size_t len = strlen(threadname);
213       if (len && threadname[len - 1] == '\n') {
214         threadname[len - 1] = '\0';
215       }
216     }
217   }
218   // Blacklist logd, logd.reader, logd.writer, logd.auditd, logd.control ...
219   static const char logd[] = "logd";
220   if (threadname != nullptr && !strncmp(threadname, logd, sizeof(logd) - 1)
221       && (!threadname[sizeof(logd) - 1] || (threadname[sizeof(logd) - 1] == '.'))) {
222     log->should_retrieve_logcat = false;
223   }
224 
225   char procnamebuf[1024];
226   char* procname = nullptr;
227 
228   snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
229   if ((fp = fopen(path, "r"))) {
230     procname = fgets(procnamebuf, sizeof(procnamebuf), fp);
231     fclose(fp);
232   }
233 
234   _LOG(log, logtype::HEADER, "pid: %d, tid: %d, name: %s  >>> %s <<<\n", pid, tid,
235        threadname ? threadname : "UNKNOWN", procname ? procname : "UNKNOWN");
236 }
237 
dump_stack_segment(Backtrace * backtrace,log_t * log,uintptr_t * sp,size_t words,int label)238 static void dump_stack_segment(
239     Backtrace* backtrace, log_t* log, uintptr_t* sp, size_t words, int label) {
240   // Read the data all at once.
241   word_t stack_data[words];
242   size_t bytes_read = backtrace->Read(*sp, reinterpret_cast<uint8_t*>(&stack_data[0]), sizeof(word_t) * words);
243   words = bytes_read / sizeof(word_t);
244   std::string line;
245   for (size_t i = 0; i < words; i++) {
246     line = "    ";
247     if (i == 0 && label >= 0) {
248       // Print the label once.
249       line += android::base::StringPrintf("#%02d  ", label);
250     } else {
251       line += "     ";
252     }
253     line += android::base::StringPrintf("%" PRIPTR "  %" PRIPTR, *sp, stack_data[i]);
254 
255     backtrace_map_t map;
256     backtrace->FillInMap(stack_data[i], &map);
257     if (BacktraceMap::IsValid(map) && !map.name.empty()) {
258       line += "  " + map.name;
259       uintptr_t offset = 0;
260       std::string func_name(backtrace->GetFunctionName(stack_data[i], &offset));
261       if (!func_name.empty()) {
262         line += " (" + func_name;
263         if (offset) {
264           line += android::base::StringPrintf("+%" PRIuPTR, offset);
265         }
266         line += ')';
267       }
268     }
269     _LOG(log, logtype::STACK, "%s\n", line.c_str());
270 
271     *sp += sizeof(word_t);
272   }
273 }
274 
dump_stack(Backtrace * backtrace,log_t * log)275 static void dump_stack(Backtrace* backtrace, log_t* log) {
276   size_t first = 0, last;
277   for (size_t i = 0; i < backtrace->NumFrames(); i++) {
278     const backtrace_frame_data_t* frame = backtrace->GetFrame(i);
279     if (frame->sp) {
280       if (!first) {
281         first = i+1;
282       }
283       last = i;
284     }
285   }
286   if (!first) {
287     return;
288   }
289   first--;
290 
291   // Dump a few words before the first frame.
292   word_t sp = backtrace->GetFrame(first)->sp - STACK_WORDS * sizeof(word_t);
293   dump_stack_segment(backtrace, log, &sp, STACK_WORDS, -1);
294 
295   // Dump a few words from all successive frames.
296   // Only log the first 3 frames, put the rest in the tombstone.
297   for (size_t i = first; i <= last; i++) {
298     const backtrace_frame_data_t* frame = backtrace->GetFrame(i);
299     if (sp != frame->sp) {
300       _LOG(log, logtype::STACK, "         ........  ........\n");
301       sp = frame->sp;
302     }
303     if (i == last) {
304       dump_stack_segment(backtrace, log, &sp, STACK_WORDS, i);
305       if (sp < frame->sp + frame->stack_size) {
306         _LOG(log, logtype::STACK, "         ........  ........\n");
307       }
308     } else {
309       size_t words = frame->stack_size / sizeof(word_t);
310       if (words == 0) {
311         words = 1;
312       } else if (words > STACK_WORDS) {
313         words = STACK_WORDS;
314       }
315       dump_stack_segment(backtrace, log, &sp, words, i);
316     }
317   }
318 }
319 
get_addr_string(uintptr_t addr)320 static std::string get_addr_string(uintptr_t addr) {
321   std::string addr_str;
322 #if defined(__LP64__)
323   addr_str = android::base::StringPrintf("%08x'%08x",
324                                          static_cast<uint32_t>(addr >> 32),
325                                          static_cast<uint32_t>(addr & 0xffffffff));
326 #else
327   addr_str = android::base::StringPrintf("%08x", addr);
328 #endif
329   return addr_str;
330 }
331 
dump_abort_message(Backtrace * backtrace,log_t * log,uintptr_t address)332 static void dump_abort_message(Backtrace* backtrace, log_t* log, uintptr_t address) {
333   if (address == 0) {
334     return;
335   }
336 
337   address += sizeof(size_t);  // Skip the buffer length.
338 
339   char msg[512];
340   memset(msg, 0, sizeof(msg));
341   char* p = &msg[0];
342   while (p < &msg[sizeof(msg)]) {
343     word_t data;
344     size_t len = sizeof(word_t);
345     if (!backtrace->ReadWord(address, &data)) {
346       break;
347     }
348     address += sizeof(word_t);
349 
350     while (len > 0 && (*p++ = (data >> (sizeof(word_t) - len) * 8) & 0xff) != 0) {
351       len--;
352     }
353   }
354   msg[sizeof(msg) - 1] = '\0';
355 
356   _LOG(log, logtype::HEADER, "Abort message: '%s'\n", msg);
357 }
358 
dump_all_maps(Backtrace * backtrace,BacktraceMap * map,log_t * log,pid_t tid)359 static void dump_all_maps(Backtrace* backtrace, BacktraceMap* map, log_t* log, pid_t tid) {
360   bool print_fault_address_marker = false;
361   uintptr_t addr = 0;
362   siginfo_t si;
363   memset(&si, 0, sizeof(si));
364   if (ptrace(PTRACE_GETSIGINFO, tid, 0, &si) != -1) {
365     print_fault_address_marker = signal_has_si_addr(si.si_signo);
366     addr = reinterpret_cast<uintptr_t>(si.si_addr);
367   } else {
368     ALOGE("Cannot get siginfo for %d: %s\n", tid, strerror(errno));
369   }
370 
371   _LOG(log, logtype::MAPS, "\n");
372   if (!print_fault_address_marker) {
373     _LOG(log, logtype::MAPS, "memory map:\n");
374   } else {
375     _LOG(log, logtype::MAPS, "memory map: (fault address prefixed with --->)\n");
376     if (map->begin() != map->end() && addr < map->begin()->start) {
377       _LOG(log, logtype::MAPS, "--->Fault address falls at %s before any mapped regions\n",
378            get_addr_string(addr).c_str());
379       print_fault_address_marker = false;
380     }
381   }
382 
383   std::string line;
384   for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) {
385     line = "    ";
386     if (print_fault_address_marker) {
387       if (addr < it->start) {
388         _LOG(log, logtype::MAPS, "--->Fault address falls at %s between mapped regions\n",
389              get_addr_string(addr).c_str());
390         print_fault_address_marker = false;
391       } else if (addr >= it->start && addr < it->end) {
392         line = "--->";
393         print_fault_address_marker = false;
394       }
395     }
396     line += get_addr_string(it->start) + '-' + get_addr_string(it->end - 1) + ' ';
397     if (it->flags & PROT_READ) {
398       line += 'r';
399     } else {
400       line += '-';
401     }
402     if (it->flags & PROT_WRITE) {
403       line += 'w';
404     } else {
405       line += '-';
406     }
407     if (it->flags & PROT_EXEC) {
408       line += 'x';
409     } else {
410       line += '-';
411     }
412     line += android::base::StringPrintf("  %8" PRIxPTR "  %8" PRIxPTR,
413                                         it->offset, it->end - it->start);
414     bool space_needed = true;
415     if (it->name.length() > 0) {
416       space_needed = false;
417       line += "  " + it->name;
418       std::string build_id;
419       if ((it->flags & PROT_READ) && elf_get_build_id(backtrace, it->start, &build_id)) {
420         line += " (BuildId: " + build_id + ")";
421       }
422     }
423     if (it->load_base != 0) {
424       if (space_needed) {
425         line += ' ';
426       }
427       line += android::base::StringPrintf(" (load base 0x%" PRIxPTR ")", it->load_base);
428     }
429     _LOG(log, logtype::MAPS, "%s\n", line.c_str());
430   }
431   if (print_fault_address_marker) {
432     _LOG(log, logtype::MAPS, "--->Fault address falls at %s after any mapped regions\n",
433          get_addr_string(addr).c_str());
434   }
435 }
436 
dump_backtrace_and_stack(Backtrace * backtrace,log_t * log)437 static void dump_backtrace_and_stack(Backtrace* backtrace, log_t* log) {
438   if (backtrace->NumFrames()) {
439     _LOG(log, logtype::BACKTRACE, "\nbacktrace:\n");
440     dump_backtrace_to_log(backtrace, log, "    ");
441 
442     _LOG(log, logtype::STACK, "\nstack:\n");
443     dump_stack(backtrace, log);
444   }
445 }
446 
dump_thread(log_t * log,pid_t pid,pid_t tid,BacktraceMap * map,int signal,int si_code,uintptr_t abort_msg_address,bool primary_thread)447 static void dump_thread(log_t* log, pid_t pid, pid_t tid, BacktraceMap* map, int signal,
448                         int si_code, uintptr_t abort_msg_address, bool primary_thread) {
449   log->current_tid = tid;
450   if (!primary_thread) {
451     _LOG(log, logtype::THREAD, "--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---\n");
452   }
453   dump_thread_info(log, pid, tid);
454 
455   if (signal) {
456     dump_signal_info(log, tid, signal, si_code);
457   }
458 
459   std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, tid, map));
460   if (primary_thread) {
461     dump_abort_message(backtrace.get(), log, abort_msg_address);
462   }
463   dump_registers(log, tid);
464   if (backtrace->Unwind(0)) {
465     dump_backtrace_and_stack(backtrace.get(), log);
466   } else {
467     ALOGE("Unwind failed: pid = %d, tid = %d", pid, tid);
468   }
469 
470   if (primary_thread) {
471     dump_memory_and_code(log, backtrace.get());
472     if (map) {
473       dump_all_maps(backtrace.get(), map, log, tid);
474     }
475   }
476 
477   log->current_tid = log->crashed_tid;
478 }
479 
480 // Reads the contents of the specified log device, filters out the entries
481 // that don't match the specified pid, and writes them to the tombstone file.
482 //
483 // If "tail" is non-zero, log the last "tail" number of lines.
484 static EventTagMap* g_eventTagMap = NULL;
485 
dump_log_file(log_t * log,pid_t pid,const char * filename,unsigned int tail)486 static void dump_log_file(
487     log_t* log, pid_t pid, const char* filename, unsigned int tail) {
488   bool first = true;
489   struct logger_list* logger_list;
490 
491   if (!log->should_retrieve_logcat) {
492     return;
493   }
494 
495   logger_list = android_logger_list_open(
496       android_name_to_log_id(filename), ANDROID_LOG_RDONLY | ANDROID_LOG_NONBLOCK, tail, pid);
497 
498   if (!logger_list) {
499     ALOGE("Unable to open %s: %s\n", filename, strerror(errno));
500     return;
501   }
502 
503   struct log_msg log_entry;
504 
505   while (true) {
506     ssize_t actual = android_logger_list_read(logger_list, &log_entry);
507     struct logger_entry* entry;
508 
509     if (actual < 0) {
510       if (actual == -EINTR) {
511         // interrupted by signal, retry
512         continue;
513       } else if (actual == -EAGAIN) {
514         // non-blocking EOF; we're done
515         break;
516       } else {
517         ALOGE("Error while reading log: %s\n", strerror(-actual));
518         break;
519       }
520     } else if (actual == 0) {
521       ALOGE("Got zero bytes while reading log: %s\n", strerror(errno));
522       break;
523     }
524 
525     // NOTE: if you ALOGV something here, this will spin forever,
526     // because you will be writing as fast as you're reading.  Any
527     // high-frequency debug diagnostics should just be written to
528     // the tombstone file.
529 
530     entry = &log_entry.entry_v1;
531 
532     if (first) {
533       _LOG(log, logtype::LOGS, "--------- %slog %s\n",
534         tail ? "tail end of " : "", filename);
535       first = false;
536     }
537 
538     // Msg format is: <priority:1><tag:N>\0<message:N>\0
539     //
540     // We want to display it in the same format as "logcat -v threadtime"
541     // (although in this case the pid is redundant).
542     static const char* kPrioChars = "!.VDIWEFS";
543     unsigned hdr_size = log_entry.entry.hdr_size;
544     if (!hdr_size) {
545       hdr_size = sizeof(log_entry.entry_v1);
546     }
547     char* msg = reinterpret_cast<char*>(log_entry.buf) + hdr_size;
548 
549     char timeBuf[32];
550     time_t sec = static_cast<time_t>(entry->sec);
551     struct tm tmBuf;
552     struct tm* ptm;
553     ptm = localtime_r(&sec, &tmBuf);
554     strftime(timeBuf, sizeof(timeBuf), "%m-%d %H:%M:%S", ptm);
555 
556     if (log_entry.id() == LOG_ID_EVENTS) {
557       if (!g_eventTagMap) {
558         g_eventTagMap = android_openEventTagMap(EVENT_TAG_MAP_FILE);
559       }
560       AndroidLogEntry e;
561       char buf[512];
562       android_log_processBinaryLogBuffer(entry, &e, g_eventTagMap, buf, sizeof(buf));
563       _LOG(log, logtype::LOGS, "%s.%03d %5d %5d %c %-8s: %s\n",
564          timeBuf, entry->nsec / 1000000, entry->pid, entry->tid,
565          'I', e.tag, e.message);
566       continue;
567     }
568 
569     unsigned char prio = msg[0];
570     char* tag = msg + 1;
571     msg = tag + strlen(tag) + 1;
572 
573     // consume any trailing newlines
574     char* nl = msg + strlen(msg) - 1;
575     while (nl >= msg && *nl == '\n') {
576       *nl-- = '\0';
577     }
578 
579     char prioChar = (prio < strlen(kPrioChars) ? kPrioChars[prio] : '?');
580 
581     // Look for line breaks ('\n') and display each text line
582     // on a separate line, prefixed with the header, like logcat does.
583     do {
584       nl = strchr(msg, '\n');
585       if (nl) {
586         *nl = '\0';
587         ++nl;
588       }
589 
590       _LOG(log, logtype::LOGS, "%s.%03d %5d %5d %c %-8s: %s\n",
591          timeBuf, entry->nsec / 1000000, entry->pid, entry->tid,
592          prioChar, tag, msg);
593     } while ((msg = nl));
594   }
595 
596   android_logger_list_free(logger_list);
597 }
598 
599 // Dumps the logs generated by the specified pid to the tombstone, from both
600 // "system" and "main" log devices.  Ideally we'd interleave the output.
dump_logs(log_t * log,pid_t pid,unsigned int tail)601 static void dump_logs(log_t* log, pid_t pid, unsigned int tail) {
602   dump_log_file(log, pid, "system", tail);
603   dump_log_file(log, pid, "main", tail);
604 }
605 
606 // Dumps all information about the specified pid to the tombstone.
dump_crash(log_t * log,BacktraceMap * map,pid_t pid,pid_t tid,const std::set<pid_t> & siblings,int signal,int si_code,uintptr_t abort_msg_address)607 static void dump_crash(log_t* log, BacktraceMap* map, pid_t pid, pid_t tid,
608                        const std::set<pid_t>& siblings, int signal, int si_code,
609                        uintptr_t abort_msg_address) {
610   // don't copy log messages to tombstone unless this is a dev device
611   char value[PROPERTY_VALUE_MAX];
612   property_get("ro.debuggable", value, "0");
613   bool want_logs = (value[0] == '1');
614 
615   _LOG(log, logtype::HEADER,
616        "*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n");
617   dump_header_info(log);
618   dump_thread(log, pid, tid, map, signal, si_code, abort_msg_address, true);
619   if (want_logs) {
620     dump_logs(log, pid, 5);
621   }
622 
623   if (!siblings.empty()) {
624     for (pid_t sibling : siblings) {
625       dump_thread(log, pid, sibling, map, 0, 0, 0, false);
626     }
627   }
628 
629   if (want_logs) {
630     dump_logs(log, pid, 0);
631   }
632 }
633 
634 // open_tombstone - find an available tombstone slot, if any, of the
635 // form tombstone_XX where XX is 00 to MAX_TOMBSTONES-1, inclusive. If no
636 // file is available, we reuse the least-recently-modified file.
open_tombstone(std::string * out_path)637 int open_tombstone(std::string* out_path) {
638   // In a single pass, find an available slot and, in case none
639   // exist, find and record the least-recently-modified file.
640   char path[128];
641   int fd = -1;
642   int oldest = -1;
643   struct stat oldest_sb;
644   for (int i = 0; i < MAX_TOMBSTONES; i++) {
645     snprintf(path, sizeof(path), TOMBSTONE_TEMPLATE, i);
646 
647     struct stat sb;
648     if (stat(path, &sb) == 0) {
649       if (oldest < 0 || sb.st_mtime < oldest_sb.st_mtime) {
650         oldest = i;
651         oldest_sb.st_mtime = sb.st_mtime;
652       }
653       continue;
654     }
655     if (errno != ENOENT) continue;
656 
657     fd = open(path, O_CREAT | O_EXCL | O_WRONLY | O_NOFOLLOW | O_CLOEXEC, 0600);
658     if (fd < 0) continue;  // raced ?
659 
660     if (out_path) {
661       *out_path = path;
662     }
663     fchown(fd, AID_SYSTEM, AID_SYSTEM);
664     return fd;
665   }
666 
667   if (oldest < 0) {
668     ALOGE("debuggerd: failed to find a valid tombstone, default to using tombstone 0.\n");
669     oldest = 0;
670   }
671 
672   // we didn't find an available file, so we clobber the oldest one
673   snprintf(path, sizeof(path), TOMBSTONE_TEMPLATE, oldest);
674   fd = open(path, O_CREAT | O_TRUNC | O_WRONLY | O_NOFOLLOW | O_CLOEXEC, 0600);
675   if (fd < 0) {
676     ALOGE("debuggerd: failed to open tombstone file '%s': %s\n", path, strerror(errno));
677     return -1;
678   }
679 
680   if (out_path) {
681     *out_path = path;
682   }
683   fchown(fd, AID_SYSTEM, AID_SYSTEM);
684   return fd;
685 }
686 
engrave_tombstone(int tombstone_fd,BacktraceMap * map,pid_t pid,pid_t tid,const std::set<pid_t> & siblings,int signal,int original_si_code,uintptr_t abort_msg_address,std::string * amfd_data)687 void engrave_tombstone(int tombstone_fd, BacktraceMap* map, pid_t pid, pid_t tid,
688                        const std::set<pid_t>& siblings, int signal, int original_si_code,
689                        uintptr_t abort_msg_address, std::string* amfd_data) {
690   log_t log;
691   log.current_tid = tid;
692   log.crashed_tid = tid;
693 
694   if (tombstone_fd < 0) {
695     ALOGE("debuggerd: skipping tombstone write, nothing to do.\n");
696     return;
697   }
698 
699   log.tfd = tombstone_fd;
700   log.amfd_data = amfd_data;
701   dump_crash(&log, map, pid, tid, siblings, signal, original_si_code, abort_msg_address);
702 }
703