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 */
46 extern 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
51 static int logsocket = -1;
52
53 #define ANDROID_LOG_INFO 4
54
55 /* Log information onto the tombstone */
_LOG(int tfd,bool in_tombstone_only,const char * fmt,...)56 void _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
parse_maps_line(char * line)85 mapinfo *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
dump_build_info(int tfd)111 void 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
dump_stack_and_code(int tfd,int pid,mapinfo * map,int unwind_depth,unsigned int sp_list[],int frame0_pc_sane,bool at_fault)121 void 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
dump_pc_and_lr(int tfd,int pid,mapinfo * map,int unwound_level,bool at_fault)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
dump_registers(int tfd,int pid,bool at_fault)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
get_signame(int sig)290 const 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
dump_fault_addr(int tfd,int pid,int sig)303 void 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
dump_crash_banner(int tfd,unsigned pid,unsigned tid,int sig)316 void 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
parse_exidx_info(mapinfo * milist,pid_t pid)338 static 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
dump_crash_report(int tfd,unsigned pid,unsigned tid,bool at_fault)372 void 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 */
find_and_open_tombstone(void)444 static 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 */
dump_sibling_thread_report(int tfd,unsigned pid,unsigned tid)491 static 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 */
engrave_tombstone(unsigned pid,unsigned tid,int debug_uid,int signal)528 static 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
555 static int
write_string(const char * file,const char * string)556 write_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
570 static
init_debug_led(void)571 void 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
582 static
enable_debug_led(void)583 void 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
591 static
disable_debug_led(void)592 void 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
600 extern int init_getevent();
601 extern void uninit_getevent();
602 extern int get_event(struct input_event* event, int timeout);
603
wait_for_user_action(unsigned tid,struct ucred * cr)604 static 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 crashed. debuggerd waiting for gdbserver \n"
610 "* \n"
611 "* adb shell gdbserver :port --attach %d & \n"
612 "* \n"
613 "* and press the HOME key. \n"
614 "********************************************************\n",
615 cr->pid, cr->pid);
616
617 /* wait for HOME key */
618 if (init_getevent() == 0) {
619 int ms = 1200 / 10;
620 int dit = 1;
621 int dah = 3*dit;
622 int _ = -dit;
623 int ___ = 3*_;
624 int _______ = 7*_;
625 const signed char codes[] = {
626 dit,_,dit,_,dit,___,dah,_,dah,_,dah,___,dit,_,dit,_,dit,_______
627 };
628 size_t s = 0;
629 struct input_event e;
630 int home = 0;
631 init_debug_led();
632 enable_debug_led();
633 do {
634 int timeout = abs((int)(codes[s])) * ms;
635 int res = get_event(&e, timeout);
636 if (res == 0) {
637 if (e.type==EV_KEY && e.code==KEY_HOME && e.value==0)
638 home = 1;
639 } else if (res == 1) {
640 if (++s >= sizeof(codes)/sizeof(*codes))
641 s = 0;
642 if (codes[s] > 0) {
643 enable_debug_led();
644 } else {
645 disable_debug_led();
646 }
647 }
648 } while (!home);
649 uninit_getevent();
650 }
651
652 /* don't forget to turn debug led off */
653 disable_debug_led();
654
655 /* close filedescriptor */
656 LOG("debuggerd resuming process %d", cr->pid);
657 }
658
handle_crashing_process(int fd)659 static void handle_crashing_process(int fd)
660 {
661 char buf[64];
662 struct stat s;
663 unsigned tid;
664 struct ucred cr;
665 int n, len, status;
666 int tid_attach_status = -1;
667 unsigned retry = 30;
668 bool need_cleanup = false;
669
670 char value[PROPERTY_VALUE_MAX];
671 property_get("debug.db.uid", value, "-1");
672 int debug_uid = atoi(value);
673
674 XLOG("handle_crashing_process(%d)\n", fd);
675
676 len = sizeof(cr);
677 n = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &len);
678 if(n != 0) {
679 LOG("cannot get credentials\n");
680 goto done;
681 }
682
683 XLOG("reading tid\n");
684 fcntl(fd, F_SETFL, O_NONBLOCK);
685 while((n = read(fd, &tid, sizeof(unsigned))) != sizeof(unsigned)) {
686 if(errno == EINTR) continue;
687 if(errno == EWOULDBLOCK) {
688 if(retry-- > 0) {
689 usleep(100 * 1000);
690 continue;
691 }
692 LOG("timed out reading tid\n");
693 goto done;
694 }
695 LOG("read failure? %s\n", strerror(errno));
696 goto done;
697 }
698
699 sprintf(buf,"/proc/%d/task/%d", cr.pid, tid);
700 if(stat(buf, &s)) {
701 LOG("tid %d does not exist in pid %d. ignorning debug request\n",
702 tid, cr.pid);
703 close(fd);
704 return;
705 }
706
707 XLOG("BOOM: pid=%d uid=%d gid=%d tid=%d\n", cr.pid, cr.uid, cr.gid, tid);
708
709 tid_attach_status = ptrace(PTRACE_ATTACH, tid, 0, 0);
710 if(tid_attach_status < 0) {
711 LOG("ptrace attach failed: %s\n", strerror(errno));
712 goto done;
713 }
714
715 close(fd);
716 fd = -1;
717
718 for(;;) {
719 n = waitpid(tid, &status, __WALL);
720
721 if(n < 0) {
722 if(errno == EAGAIN) continue;
723 LOG("waitpid failed: %s\n", strerror(errno));
724 goto done;
725 }
726
727 XLOG("waitpid: n=%d status=%08x\n", n, status);
728
729 if(WIFSTOPPED(status)){
730 n = WSTOPSIG(status);
731 switch(n) {
732 case SIGSTOP:
733 XLOG("stopped -- continuing\n");
734 n = ptrace(PTRACE_CONT, tid, 0, 0);
735 if(n) {
736 LOG("ptrace failed: %s\n", strerror(errno));
737 goto done;
738 }
739 continue;
740
741 case SIGILL:
742 case SIGABRT:
743 case SIGBUS:
744 case SIGFPE:
745 case SIGSEGV:
746 case SIGSTKFLT: {
747 XLOG("stopped -- fatal signal\n");
748 need_cleanup = engrave_tombstone(cr.pid, tid, debug_uid, n);
749 kill(tid, SIGSTOP);
750 goto done;
751 }
752
753 default:
754 XLOG("stopped -- unexpected signal\n");
755 goto done;
756 }
757 } else {
758 XLOG("unexpected waitpid response\n");
759 goto done;
760 }
761 }
762
763 done:
764 XLOG("detaching\n");
765
766 /* stop the process so we can debug */
767 kill(cr.pid, SIGSTOP);
768
769 /*
770 * If a thread has been attached by ptrace, make sure it is detached
771 * successfully otherwise we will get a zombie.
772 */
773 if (tid_attach_status == 0) {
774 int detach_status;
775 /* detach so we can attach gdbserver */
776 detach_status = ptrace(PTRACE_DETACH, tid, 0, 0);
777 need_cleanup |= (detach_status != 0);
778 }
779
780 /*
781 * if debug.db.uid is set, its value indicates if we should wait
782 * for user action for the crashing process.
783 * in this case, we log a message and turn the debug LED on
784 * waiting for a gdb connection (for instance)
785 */
786
787 if ((signed)cr.uid <= debug_uid) {
788 wait_for_user_action(tid, &cr);
789 }
790
791 /* resume stopped process (so it can crash in peace) */
792 kill(cr.pid, SIGCONT);
793
794 if (need_cleanup) {
795 LOG("debuggerd committing suicide to free the zombie!\n");
796 kill(getpid(), SIGKILL);
797 }
798
799 if(fd != -1) close(fd);
800 }
801
main()802 int main()
803 {
804 int s;
805 struct sigaction act;
806
807 logsocket = socket_local_client("logd",
808 ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_DGRAM);
809 if(logsocket < 0) {
810 logsocket = -1;
811 } else {
812 fcntl(logsocket, F_SETFD, FD_CLOEXEC);
813 }
814
815 act.sa_handler = SIG_DFL;
816 sigemptyset(&act.sa_mask);
817 sigaddset(&act.sa_mask,SIGCHLD);
818 act.sa_flags = SA_NOCLDWAIT;
819 sigaction(SIGCHLD, &act, 0);
820
821 s = socket_local_server("android:debuggerd",
822 ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM);
823 if(s < 0) return -1;
824 fcntl(s, F_SETFD, FD_CLOEXEC);
825
826 LOG("debuggerd: " __DATE__ " " __TIME__ "\n");
827
828 for(;;) {
829 struct sockaddr addr;
830 socklen_t alen;
831 int fd;
832
833 alen = sizeof(addr);
834 fd = accept(s, &addr, &alen);
835 if(fd < 0) continue;
836
837 fcntl(fd, F_SETFD, FD_CLOEXEC);
838
839 handle_crashing_process(fd);
840 }
841 return 0;
842 }
843