debuggerd.c revision 4f6e8d7a00cbeda1e70cc15be9c4af1018bdad53 
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 char **process_name_ptr;
52
53static int logsocket = -1;
54
55#define ANDROID_LOG_INFO 4
56
57/* Log information onto the tombstone */
58void _LOG(int tfd, bool in_tombstone_only, const char *fmt, ...)
59{
60    char buf[128];
61
62    va_list ap;
63    va_start(ap, fmt);
64
65    if (tfd >= 0) {
66        int len;
67        vsnprintf(buf, sizeof(buf), fmt, ap);
68        len = strlen(buf);
69        if(tfd >= 0) write(tfd, buf, len);
70    }
71
72    if (!in_tombstone_only)
73        __android_log_vprint(ANDROID_LOG_INFO, "DEBUG", fmt, ap);
74}
75
76#define LOG(fmt...) _LOG(-1, 0, fmt)
77#if 0
78#define XLOG(fmt...) _LOG(-1, 0, fmt)
79#else
80#define XLOG(fmt...) do {} while(0)
81#endif
82
83// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419   /system/lib/libcomposer.so
84// 012345678901234567890123456789012345678901234567890123456789
85// 0         1         2         3         4         5
86
87mapinfo *parse_maps_line(char *line)
88{
89    mapinfo *mi;
90    int len = strlen(line);
91
92    if(len < 1) return 0;
93    line[--len] = 0;
94
95    if(len < 50) return 0;
96    if(line[20] != 'x') return 0;
97
98    mi = malloc(sizeof(mapinfo) + (len - 47));
99    if(mi == 0) return 0;
100
101    mi->start = strtoul(line, 0, 16);
102    mi->end = strtoul(line + 9, 0, 16);
103    /* To be filled in parse_exidx_info if the mapped section starts with
104     * elf_header
105     */
106    mi->exidx_start = mi->exidx_end = 0;
107    mi->next = 0;
108    strcpy(mi->name, line + 49);
109
110    return mi;
111}
112
113void dump_build_info(int tfd)
114{
115    char fingerprint[PROPERTY_VALUE_MAX];
116
117    property_get("ro.build.fingerprint", fingerprint, "unknown");
118
119    _LOG(tfd, false, "Build fingerprint: '%s'\n", fingerprint);
120}
121
122
123void dump_stack_and_code(int tfd, int pid, mapinfo *map,
124                         int unwind_depth, unsigned int sp_list[],
125                         int frame0_pc_sane, bool at_fault)
126{
127    unsigned int sp, pc, p, end, data;
128    struct pt_regs r;
129    int sp_depth;
130    bool only_in_tombstone = !at_fault;
131
132    if(ptrace(PTRACE_GETREGS, pid, 0, &r)) return;
133    sp = r.ARM_sp;
134    pc = r.ARM_pc;
135
136    /* Died because calling the weeds - dump
137     * the code around the PC in the next frame instead.
138     */
139    if (frame0_pc_sane == 0) {
140        pc = r.ARM_lr;
141    }
142
143    _LOG(tfd, true, "code%s:\n", frame0_pc_sane ? "" : " (around frame #01)");
144
145    end = p = pc & ~3;
146    p -= 16;
147
148    /* Dump the code as:
149     *  PC         contents
150     *  00008d34   fffffcd0 4c0eb530 b0934a0e 1c05447c
151     *  00008d44   f7ff18a0 490ced94 68035860 d0012b00
152     */
153    while (p <= end) {
154        int i;
155
156        _LOG(tfd, true, " %08x  ", p);
157        for (i = 0; i < 4; i++) {
158            data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL);
159            _LOG(tfd, true, " %08x", data);
160            p += 4;
161        }
162        _LOG(tfd, true, "\n", p);
163    }
164
165    p = sp - 64;
166    p &= ~3;
167    if (unwind_depth != 0) {
168        if (unwind_depth < STACK_CONTENT_DEPTH) {
169            end = sp_list[unwind_depth-1];
170        }
171        else {
172            end = sp_list[STACK_CONTENT_DEPTH-1];
173        }
174    }
175    else {
176        end = sp | 0x000000ff;
177        end += 0xff;
178    }
179
180    _LOG(tfd, only_in_tombstone, "stack:\n");
181
182    /* If the crash is due to PC == 0, there will be two frames that
183     * have identical SP value.
184     */
185    if (sp_list[0] == sp_list[1]) {
186        sp_depth = 1;
187    }
188    else {
189        sp_depth = 0;
190    }
191
192    while (p <= end) {
193         char *prompt;
194         char level[16];
195         data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL);
196         if (p == sp_list[sp_depth]) {
197             sprintf(level, "#%02d", sp_depth++);
198             prompt = level;
199         }
200         else {
201             prompt = "   ";
202         }
203
204         /* Print the stack content in the log for the first 3 frames. For the
205          * rest only print them in the tombstone file.
206          */
207         _LOG(tfd, (sp_depth > 2) || only_in_tombstone,
208              "%s %08x  %08x  %s\n", prompt, p, data,
209              map_to_name(map, data, ""));
210         p += 4;
211    }
212    /* print another 64-byte of stack data after the last frame */
213
214    end = p+64;
215    while (p <= end) {
216         data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL);
217         _LOG(tfd, (sp_depth > 2) || only_in_tombstone,
218              "    %08x  %08x  %s\n", p, data,
219              map_to_name(map, data, ""));
220         p += 4;
221    }
222}
223
224void dump_pc_and_lr(int tfd, int pid, mapinfo *map, int unwound_level,
225                    bool at_fault)
226{
227    struct pt_regs r;
228
229    if(ptrace(PTRACE_GETREGS, pid, 0, &r)) {
230        _LOG(tfd, !at_fault, "tid %d not responding!\n", pid);
231        return;
232    }
233
234    if (unwound_level == 0) {
235        _LOG(tfd, !at_fault, "         #%02d  pc %08x  %s\n", 0, r.ARM_pc,
236             map_to_name(map, r.ARM_pc, "<unknown>"));
237    }
238    _LOG(tfd, !at_fault, "         #%02d  lr %08x  %s\n", 1, r.ARM_lr,
239            map_to_name(map, r.ARM_lr, "<unknown>"));
240}
241
242void dump_registers(int tfd, int pid, bool at_fault)
243{
244    struct pt_regs r;
245    bool only_in_tombstone = !at_fault;
246
247    if(ptrace(PTRACE_GETREGS, pid, 0, &r)) {
248        _LOG(tfd, only_in_tombstone,
249             "cannot get registers: %s\n", strerror(errno));
250        return;
251    }
252
253    _LOG(tfd, only_in_tombstone, " r0 %08x  r1 %08x  r2 %08x  r3 %08x\n",
254         r.ARM_r0, r.ARM_r1, r.ARM_r2, r.ARM_r3);
255    _LOG(tfd, only_in_tombstone, " r4 %08x  r5 %08x  r6 %08x  r7 %08x\n",
256         r.ARM_r4, r.ARM_r5, r.ARM_r6, r.ARM_r7);
257    _LOG(tfd, only_in_tombstone, " r8 %08x  r9 %08x  10 %08x  fp %08x\n",
258         r.ARM_r8, r.ARM_r9, r.ARM_r10, r.ARM_fp);
259    _LOG(tfd, only_in_tombstone,
260         " ip %08x  sp %08x  lr %08x  pc %08x  cpsr %08x\n",
261         r.ARM_ip, r.ARM_sp, r.ARM_lr, r.ARM_pc, r.ARM_cpsr);
262}
263
264const char *get_signame(int sig)
265{
266    switch(sig) {
267    case SIGILL:     return "SIGILL";
268    case SIGABRT:    return "SIGABRT";
269    case SIGBUS:     return "SIGBUS";
270    case SIGFPE:     return "SIGFPE";
271    case SIGSEGV:    return "SIGSEGV";
272    case SIGSTKFLT:  return "SIGSTKFLT";
273    default:         return "?";
274    }
275}
276
277void dump_fault_addr(int tfd, int pid, int sig)
278{
279    siginfo_t si;
280
281    memset(&si, 0, sizeof(si));
282    if(ptrace(PTRACE_GETSIGINFO, pid, 0, &si)){
283        _LOG(tfd, false, "cannot get siginfo: %s\n", strerror(errno));
284    } else {
285        _LOG(tfd, false, "signal %d (%s), fault addr %08x\n",
286            sig, get_signame(sig), si.si_addr);
287    }
288}
289
290void dump_crash_banner(int tfd, unsigned pid, unsigned tid, int sig)
291{
292    char data[1024];
293    char *x = 0;
294    FILE *fp;
295
296    sprintf(data, "/proc/%d/cmdline", pid);
297    fp = fopen(data, "r");
298    if(fp) {
299        x = fgets(data, 1024, fp);
300        fclose(fp);
301    }
302
303    _LOG(tfd, false,
304         "*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n");
305    dump_build_info(tfd);
306    _LOG(tfd, false, "pid: %d, tid: %d  >>> %s <<<\n",
307         pid, tid, x ? x : "UNKNOWN");
308
309    if(sig) dump_fault_addr(tfd, tid, sig);
310}
311
312static void parse_exidx_info(mapinfo *milist, pid_t pid)
313{
314    mapinfo *mi;
315    for (mi = milist; mi != NULL; mi = mi->next) {
316        Elf32_Ehdr ehdr;
317
318        memset(&ehdr, 0, sizeof(Elf32_Ehdr));
319        /* Read in sizeof(Elf32_Ehdr) worth of data from the beginning of
320         * mapped section.
321         */
322        get_remote_struct(pid, (void *) (mi->start), &ehdr,
323                          sizeof(Elf32_Ehdr));
324        /* Check if it has the matching magic words */
325        if (IS_ELF(ehdr)) {
326            Elf32_Phdr phdr;
327            Elf32_Phdr *ptr;
328            int i;
329
330            ptr = (Elf32_Phdr *) (mi->start + ehdr.e_phoff);
331            for (i = 0; i < ehdr.e_phnum; i++) {
332                /* Parse the program header */
333                get_remote_struct(pid, (void *) ptr+i, &phdr,
334                                  sizeof(Elf32_Phdr));
335                /* Found a EXIDX segment? */
336                if (phdr.p_type == PT_ARM_EXIDX) {
337                    mi->exidx_start = mi->start + phdr.p_offset;
338                    mi->exidx_end = mi->exidx_start + phdr.p_filesz;
339                    break;
340                }
341            }
342        }
343    }
344}
345
346void dump_crash_report(int tfd, unsigned pid, unsigned tid, bool at_fault)
347{
348    char data[1024];
349    FILE *fp;
350    mapinfo *milist = 0;
351    unsigned int sp_list[STACK_CONTENT_DEPTH];
352    int stack_depth;
353    int frame0_pc_sane = 1;
354
355    if (!at_fault) {
356        _LOG(tfd, true,
357         "--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---\n");
358        _LOG(tfd, true, "pid: %d, tid: %d\n", pid, tid);
359    }
360
361    dump_registers(tfd, tid, at_fault);
362
363    /* Clear stack pointer records */
364    memset(sp_list, 0, sizeof(sp_list));
365
366    sprintf(data, "/proc/%d/maps", pid);
367    fp = fopen(data, "r");
368    if(fp) {
369        while(fgets(data, 1024, fp)) {
370            mapinfo *mi = parse_maps_line(data);
371            if(mi) {
372                mi->next = milist;
373                milist = mi;
374            }
375        }
376        fclose(fp);
377    }
378
379    parse_exidx_info(milist, tid);
380
381    /* If stack unwinder fails, use the default solution to dump the stack
382     * content.
383     */
384    stack_depth = unwind_backtrace_with_ptrace(tfd, tid, milist, sp_list,
385                                               &frame0_pc_sane, at_fault);
386
387    /* The stack unwinder should at least unwind two levels of stack. If less
388     * level is seen we make sure at lease pc and lr are dumped.
389     */
390    if (stack_depth < 2) {
391        dump_pc_and_lr(tfd, tid, milist, stack_depth, at_fault);
392    }
393
394    dump_stack_and_code(tfd, tid, milist, stack_depth, sp_list, frame0_pc_sane,
395                        at_fault);
396
397    while(milist) {
398        mapinfo *next = milist->next;
399        free(milist);
400        milist = next;
401    }
402}
403
404/* FIXME: unused: use it or lose it*/
405#if 0
406static
407void start_gdbserver_vs(int pid, int port)
408{
409    pid_t p;
410    char *args[5];
411    char commspec[16];
412    char pidspec[16];
413
414    p = fork();
415    if(p < 0) {
416        LOG("could not fork()\n");
417        return;
418    }
419
420    if(p == 0) {
421        sprintf(commspec, ":%d", port);
422        sprintf(pidspec, "%d", pid);
423        args[0] = "/system/bin/gdbserver";
424        args[1] = commspec;
425        args[2] = "--attach";
426        args[3] = pidspec;
427        args[4] = 0;
428        exit(execv(args[0], args));
429    } else {
430        LOG("gdbserver pid=%d port=%d targetpid=%d\n",
431            p, port, pid);
432
433        sleep(5);
434    }
435}
436#endif
437
438#define MAX_TOMBSTONES	10
439
440#define typecheck(x,y) {    \
441    typeof(x) __dummy1;     \
442    typeof(y) __dummy2;     \
443    (void)(&__dummy1 == &__dummy2); }
444
445#define TOMBSTONE_DIR	"/data/tombstones"
446
447/*
448 * find_and_open_tombstone - find an available tombstone slot, if any, of the
449 * form tombstone_XX where XX is 00 to MAX_TOMBSTONES-1, inclusive. If no
450 * file is available, we reuse the least-recently-modified file.
451 */
452static int find_and_open_tombstone(void)
453{
454    unsigned long mtime = ULONG_MAX;
455    struct stat sb;
456    char path[128];
457    int fd, i, oldest = 0;
458
459    /*
460     * XXX: Our stat.st_mtime isn't time_t. If it changes, as it probably ought
461     * to, our logic breaks. This check will generate a warning if that happens.
462     */
463    typecheck(mtime, sb.st_mtime);
464
465    /*
466     * In a single wolf-like pass, find an available slot and, in case none
467     * exist, find and record the least-recently-modified file.
468     */
469    for (i = 0; i < MAX_TOMBSTONES; i++) {
470        snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", i);
471
472        if (!stat(path, &sb)) {
473            if (sb.st_mtime < mtime) {
474                oldest = i;
475                mtime = sb.st_mtime;
476            }
477            continue;
478        }
479        if (errno != ENOENT)
480            continue;
481
482        fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0600);
483        if (fd < 0)
484            continue;	/* raced ? */
485
486        fchown(fd, AID_SYSTEM, AID_SYSTEM);
487        return fd;
488    }
489
490    /* we didn't find an available file, so we clobber the oldest one */
491    snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", oldest);
492    fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
493    fchown(fd, AID_SYSTEM, AID_SYSTEM);
494
495    return fd;
496}
497
498/* Return true if some thread is not detached cleanly */
499static bool dump_sibling_thread_report(int tfd, unsigned pid, unsigned tid)
500{
501    char task_path[1024];
502
503    sprintf(task_path, "/proc/%d/task", pid);
504    DIR *d;
505    struct dirent *de;
506    int need_cleanup = 0;
507
508    d = opendir(task_path);
509    /* Bail early if cannot open the task directory */
510    if (d == NULL) {
511        XLOG("Cannot open /proc/%d/task\n", pid);
512        return false;
513    }
514    while ((de = readdir(d)) != NULL) {
515        unsigned new_tid;
516        /* Ignore "." and ".." */
517        if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
518            continue;
519        new_tid = atoi(de->d_name);
520        /* The main thread at fault has been handled individually */
521        if (new_tid == tid)
522            continue;
523
524        /* Skip this thread if cannot ptrace it */
525        if (ptrace(PTRACE_ATTACH, new_tid, 0, 0) < 0)
526            continue;
527
528        dump_crash_report(tfd, pid, new_tid, false);
529        need_cleanup |= ptrace(PTRACE_DETACH, new_tid, 0, 0);
530    }
531    closedir(d);
532    return need_cleanup != 0;
533}
534
535/* Return true if some thread is not detached cleanly */
536static bool engrave_tombstone(unsigned pid, unsigned tid, int debug_uid,
537                              int signal)
538{
539    int fd;
540    bool need_cleanup = false;
541
542    mkdir(TOMBSTONE_DIR, 0755);
543    chown(TOMBSTONE_DIR, AID_SYSTEM, AID_SYSTEM);
544
545    fd = find_and_open_tombstone();
546    if (fd < 0)
547        return need_cleanup;
548
549    dump_crash_banner(fd, pid, tid, signal);
550    dump_crash_report(fd, pid, tid, true);
551    /*
552     * If the user has requested to attach gdb, don't collect the per-thread
553     * information as it increases the chance to lose track of the process.
554     */
555    if ((signed)pid > debug_uid) {
556        need_cleanup = dump_sibling_thread_report(fd, pid, tid);
557    }
558
559    close(fd);
560    return need_cleanup;
561}
562
563static int
564write_string(const char* file, const char* string)
565{
566    int len;
567    int fd;
568    ssize_t amt;
569    fd = open(file, O_RDWR);
570    len = strlen(string);
571    if (fd < 0)
572        return -errno;
573    amt = write(fd, string, len);
574    close(fd);
575    return amt >= 0 ? 0 : -errno;
576}
577
578static
579void init_debug_led(void)
580{
581    // trout leds
582    write_string("/sys/class/leds/red/brightness", "0");
583    write_string("/sys/class/leds/green/brightness", "0");
584    write_string("/sys/class/leds/blue/brightness", "0");
585    write_string("/sys/class/leds/red/device/blink", "0");
586    // sardine leds
587    write_string("/sys/class/leds/left/cadence", "0,0");
588}
589
590static
591void enable_debug_led(void)
592{
593    // trout leds
594    write_string("/sys/class/leds/red/brightness", "255");
595    // sardine leds
596    write_string("/sys/class/leds/left/cadence", "1,0");
597}
598
599static
600void disable_debug_led(void)
601{
602    // trout leds
603    write_string("/sys/class/leds/red/brightness", "0");
604    // sardine leds
605    write_string("/sys/class/leds/left/cadence", "0,0");
606}
607
608extern int init_getevent();
609extern void uninit_getevent();
610extern int get_event(struct input_event* event, int timeout);
611
612static void wait_for_user_action(unsigned tid, struct ucred* cr)
613{
614    (void)tid;
615    /* First log a helpful message */
616    LOG(    "********************************************************\n"
617            "* process %d crashed. debuggerd waiting for gdbserver   \n"
618            "*                                                       \n"
619            "*     adb shell gdbserver :port --attach %d &           \n"
620            "*                                                       \n"
621            "* and press the HOME key.                               \n"
622            "********************************************************\n",
623            cr->pid, cr->pid);
624
625    /* wait for HOME key */
626    if (init_getevent() == 0) {
627        int ms = 1200 / 10;
628        int dit = 1;
629        int dah = 3*dit;
630        int _       = -dit;
631        int ___     = 3*_;
632        int _______ = 7*_;
633        const signed char codes[] = {
634           dit,_,dit,_,dit,___,dah,_,dah,_,dah,___,dit,_,dit,_,dit,_______
635        };
636        size_t s = 0;
637        struct input_event e;
638        int home = 0;
639        init_debug_led();
640        enable_debug_led();
641        do {
642            int timeout = abs((int)(codes[s])) * ms;
643            int res = get_event(&e, timeout);
644            if (res == 0) {
645                if (e.type==EV_KEY && e.code==KEY_HOME && e.value==0)
646                    home = 1;
647            } else if (res == 1) {
648                if (++s >= sizeof(codes)/sizeof(*codes))
649                    s = 0;
650                if (codes[s] > 0) {
651                    enable_debug_led();
652                } else {
653                    disable_debug_led();
654                }
655            }
656        } while (!home);
657        uninit_getevent();
658    }
659
660    /* don't forget to turn debug led off */
661    disable_debug_led();
662
663    /* close filedescriptor */
664    LOG("debuggerd resuming process %d", cr->pid);
665 }
666
667static void handle_crashing_process(int fd)
668{
669    char buf[64];
670    struct stat s;
671    unsigned tid;
672    struct ucred cr;
673    int n, len, status;
674    int tid_attach_status = -1;
675    unsigned retry = 30;
676    bool need_cleanup = false;
677
678    char value[PROPERTY_VALUE_MAX];
679    property_get("debug.db.uid", value, "-1");
680    int debug_uid = atoi(value);
681
682    XLOG("handle_crashing_process(%d)\n", fd);
683
684    len = sizeof(cr);
685    n = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &len);
686    if(n != 0) {
687        LOG("cannot get credentials\n");
688        goto done;
689    }
690
691    XLOG("reading tid\n");
692    fcntl(fd, F_SETFL, O_NONBLOCK);
693    while((n = read(fd, &tid, sizeof(unsigned))) != sizeof(unsigned)) {
694        if(errno == EINTR) continue;
695        if(errno == EWOULDBLOCK) {
696            if(retry-- > 0) {
697                usleep(100 * 1000);
698                continue;
699            }
700            LOG("timed out reading tid\n");
701            goto done;
702        }
703        LOG("read failure? %s\n", strerror(errno));
704        goto done;
705    }
706
707    sprintf(buf,"/proc/%d/task/%d", cr.pid, tid);
708    if(stat(buf, &s)) {
709        LOG("tid %d does not exist in pid %d. ignorning debug request\n",
710            tid, cr.pid);
711        close(fd);
712        return;
713    }
714
715    XLOG("BOOM: pid=%d uid=%d gid=%d tid=%d\n", cr.pid, cr.uid, cr.gid, tid);
716
717    tid_attach_status = ptrace(PTRACE_ATTACH, tid, 0, 0);
718    if(tid_attach_status < 0) {
719        LOG("ptrace attach failed: %s\n", strerror(errno));
720        goto done;
721    }
722
723    close(fd);
724    fd = -1;
725
726    for(;;) {
727        n = waitpid(tid, &status, __WALL);
728
729        if(n < 0) {
730            if(errno == EAGAIN) continue;
731            LOG("waitpid failed: %s\n", strerror(errno));
732            goto done;
733        }
734
735        XLOG("waitpid: n=%d status=%08x\n", n, status);
736
737        if(WIFSTOPPED(status)){
738            n = WSTOPSIG(status);
739            switch(n) {
740            case SIGSTOP:
741                XLOG("stopped -- continuing\n");
742                n = ptrace(PTRACE_CONT, tid, 0, 0);
743                if(n) {
744                    LOG("ptrace failed: %s\n", strerror(errno));
745                    goto done;
746                }
747                continue;
748
749            case SIGILL:
750            case SIGABRT:
751            case SIGBUS:
752            case SIGFPE:
753            case SIGSEGV:
754            case SIGSTKFLT: {
755                XLOG("stopped -- fatal signal\n");
756                need_cleanup = engrave_tombstone(cr.pid, tid, debug_uid, n);
757                kill(tid, SIGSTOP);
758                goto done;
759            }
760
761            default:
762                XLOG("stopped -- unexpected signal\n");
763                goto done;
764            }
765        } else {
766            XLOG("unexpected waitpid response\n");
767            goto done;
768        }
769    }
770
771done:
772    XLOG("detaching\n");
773
774    /* stop the process so we can debug */
775    kill(cr.pid, SIGSTOP);
776
777    /*
778     * If a thread has been attached by ptrace, make sure it is detached
779     * successfully otherwise we will get a zombie.
780     */
781    if (tid_attach_status == 0) {
782        int detach_status;
783        /* detach so we can attach gdbserver */
784        detach_status = ptrace(PTRACE_DETACH, tid, 0, 0);
785        need_cleanup |= (detach_status != 0);
786    }
787
788    /*
789     * if debug.db.uid is set, its value indicates if we should wait
790     * for user action for the crashing process.
791     * in this case, we log a message and turn the debug LED on
792     * waiting for a gdb connection (for instance)
793     */
794
795    if ((signed)cr.uid <= debug_uid) {
796        wait_for_user_action(tid, &cr);
797    }
798
799    /* resume stopped process (so it can crash in peace) */
800    kill(cr.pid, SIGCONT);
801
802    if (need_cleanup) {
803        LOG("debuggerd committing suicide to free the zombie!\n");
804        kill(getpid(), SIGKILL);
805    }
806
807    if(fd != -1) close(fd);
808}
809
810int main(int argc, char **argv)
811{
812    int s;
813    struct sigaction act;
814
815    process_name_ptr = argv;
816
817    logsocket = socket_local_client("logd",
818            ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_DGRAM);
819    if(logsocket < 0) {
820        logsocket = -1;
821    } else {
822        fcntl(logsocket, F_SETFD, FD_CLOEXEC);
823    }
824
825    act.sa_handler = SIG_DFL;
826    sigemptyset(&act.sa_mask);
827    sigaddset(&act.sa_mask,SIGCHLD);
828    act.sa_flags = SA_NOCLDWAIT;
829    sigaction(SIGCHLD, &act, 0);
830
831    s = socket_local_server("android:debuggerd",
832            ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM);
833    if(s < 0) return -1;
834    fcntl(s, F_SETFD, FD_CLOEXEC);
835
836    LOG("debuggerd: " __DATE__ " " __TIME__ "\n");
837
838    for(;;) {
839        struct sockaddr addr;
840        socklen_t alen;
841        int fd;
842
843        alen = sizeof(addr);
844        fd = accept(s, &addr, &alen);
845        if(fd < 0) continue;
846
847        fcntl(fd, F_SETFD, FD_CLOEXEC);
848
849        handle_crashing_process(fd);
850    }
851    return 0;
852}
853