libc_logging.cpp revision c78368f04faa4ee17f546985809e7550f3f88636 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include "../private/libc_logging.h" // Relative path so we can #include this .cpp file for testing.
30#include "../private/ScopedPthreadMutexLocker.h"
31
32#include <assert.h>
33#include <errno.h>
34#include <fcntl.h>
35#include <pthread.h>
36#include <stdarg.h>
37#include <stddef.h>
38#include <stdlib.h>
39#include <string.h>
40#include <sys/mman.h>
41#include <sys/socket.h>
42#include <sys/types.h>
43#include <sys/uio.h>
44#include <sys/un.h>
45#include <time.h>
46#include <unistd.h>
47
48static pthread_mutex_t gAbortMsgLock = PTHREAD_MUTEX_INITIALIZER;
49
50__LIBC_HIDDEN__ abort_msg_t** __abort_message_ptr; // Accessible to __libc_init_common.
51
52// Must be kept in sync with frameworks/base/core/java/android/util/EventLog.java.
53enum AndroidEventLogType {
54  EVENT_TYPE_INT      = 0,
55  EVENT_TYPE_LONG     = 1,
56  EVENT_TYPE_STRING   = 2,
57  EVENT_TYPE_LIST     = 3,
58};
59
60struct BufferOutputStream {
61 public:
62  BufferOutputStream(char* buffer, size_t size) : total(0) {
63    buffer_ = buffer;
64    end_ = buffer + size - 1;
65    pos_ = buffer_;
66    pos_[0] = '\0';
67  }
68
69  ~BufferOutputStream() {
70  }
71
72  void Send(const char* data, int len) {
73    if (len < 0) {
74      len = strlen(data);
75    }
76
77    while (len > 0) {
78      int avail = end_ - pos_;
79      if (avail == 0) {
80        break;
81      }
82      if (avail > len) {
83        avail = len;
84      }
85      memcpy(pos_, data, avail);
86      pos_ += avail;
87      pos_[0] = '\0';
88      len -= avail;
89      total += avail;
90    }
91  }
92
93  int total;
94
95 private:
96  char* buffer_;
97  char* pos_;
98  char* end_;
99};
100
101struct FdOutputStream {
102 public:
103  FdOutputStream(int fd) : total(0), fd_(fd) {
104  }
105
106  void Send(const char* data, int len) {
107    if (len < 0) {
108      len = strlen(data);
109    }
110
111    while (len > 0) {
112      int rc = TEMP_FAILURE_RETRY(write(fd_, data, len));
113      if (rc == -1) {
114        break;
115      }
116      data += rc;
117      len -= rc;
118      total += rc;
119    }
120  }
121
122  int total;
123
124 private:
125  int fd_;
126};
127
128/*** formatted output implementation
129 ***/
130
131/* Parse a decimal string from 'format + *ppos',
132 * return the value, and writes the new position past
133 * the decimal string in '*ppos' on exit.
134 *
135 * NOTE: Does *not* handle a sign prefix.
136 */
137static unsigned parse_decimal(const char *format, int *ppos) {
138    const char* p = format + *ppos;
139    unsigned result = 0;
140
141    for (;;) {
142        int ch = *p;
143        unsigned d = static_cast<unsigned>(ch - '0');
144
145        if (d >= 10U) {
146            break;
147        }
148
149        result = result*10 + d;
150        p++;
151    }
152    *ppos = p - format;
153    return result;
154}
155
156// Writes number 'value' in base 'base' into buffer 'buf' of size 'buf_size' bytes.
157// Assumes that buf_size > 0.
158static void format_unsigned(char* buf, size_t buf_size, uint64_t value, int base, bool caps) {
159  char* p = buf;
160  char* end = buf + buf_size - 1;
161
162  // Generate digit string in reverse order.
163  while (value) {
164    unsigned d = value % base;
165    value /= base;
166    if (p != end) {
167      char ch;
168      if (d < 10) {
169        ch = '0' + d;
170      } else {
171        ch = (caps ? 'A' : 'a') + (d - 10);
172      }
173      *p++ = ch;
174    }
175  }
176
177  // Special case for 0.
178  if (p == buf) {
179    if (p != end) {
180      *p++ = '0';
181    }
182  }
183  *p = '\0';
184
185  // Reverse digit string in-place.
186  size_t length = p - buf;
187  for (size_t i = 0, j = length - 1; i < j; ++i, --j) {
188    char ch = buf[i];
189    buf[i] = buf[j];
190    buf[j] = ch;
191  }
192}
193
194static void format_integer(char* buf, size_t buf_size, uint64_t value, char conversion) {
195  // Decode the conversion specifier.
196  int is_signed = (conversion == 'd' || conversion == 'i' || conversion == 'o');
197  int base = 10;
198  if (conversion == 'x' || conversion == 'X') {
199    base = 16;
200  } else if (conversion == 'o') {
201    base = 8;
202  }
203  bool caps = (conversion == 'X');
204
205  if (is_signed && static_cast<int64_t>(value) < 0) {
206    buf[0] = '-';
207    buf += 1;
208    buf_size -= 1;
209    value = static_cast<uint64_t>(-static_cast<int64_t>(value));
210  }
211  format_unsigned(buf, buf_size, value, base, caps);
212}
213
214template <typename Out>
215static void SendRepeat(Out& o, char ch, int count) {
216  char pad[8];
217  memset(pad, ch, sizeof(pad));
218
219  const int pad_size = static_cast<int>(sizeof(pad));
220  while (count > 0) {
221    int avail = count;
222    if (avail > pad_size) {
223      avail = pad_size;
224    }
225    o.Send(pad, avail);
226    count -= avail;
227  }
228}
229
230/* Perform formatted output to an output target 'o' */
231template <typename Out>
232static void out_vformat(Out& o, const char* format, va_list args) {
233    int nn = 0;
234
235    for (;;) {
236        int mm;
237        int padZero = 0;
238        int padLeft = 0;
239        char sign = '\0';
240        int width = -1;
241        int prec  = -1;
242        size_t bytelen = sizeof(int);
243        int slen;
244        char buffer[32];  /* temporary buffer used to format numbers */
245
246        char  c;
247
248        /* first, find all characters that are not 0 or '%' */
249        /* then send them to the output directly */
250        mm = nn;
251        do {
252            c = format[mm];
253            if (c == '\0' || c == '%')
254                break;
255            mm++;
256        } while (1);
257
258        if (mm > nn) {
259            o.Send(format+nn, mm-nn);
260            nn = mm;
261        }
262
263        /* is this it ? then exit */
264        if (c == '\0')
265            break;
266
267        /* nope, we are at a '%' modifier */
268        nn++;  // skip it
269
270        /* parse flags */
271        for (;;) {
272            c = format[nn++];
273            if (c == '\0') {  /* single trailing '%' ? */
274                c = '%';
275                o.Send(&c, 1);
276                return;
277            }
278            else if (c == '0') {
279                padZero = 1;
280                continue;
281            }
282            else if (c == '-') {
283                padLeft = 1;
284                continue;
285            }
286            else if (c == ' ' || c == '+') {
287                sign = c;
288                continue;
289            }
290            break;
291        }
292
293        /* parse field width */
294        if ((c >= '0' && c <= '9')) {
295            nn --;
296            width = static_cast<int>(parse_decimal(format, &nn));
297            c = format[nn++];
298        }
299
300        /* parse precision */
301        if (c == '.') {
302            prec = static_cast<int>(parse_decimal(format, &nn));
303            c = format[nn++];
304        }
305
306        /* length modifier */
307        switch (c) {
308        case 'h':
309            bytelen = sizeof(short);
310            if (format[nn] == 'h') {
311                bytelen = sizeof(char);
312                nn += 1;
313            }
314            c = format[nn++];
315            break;
316        case 'l':
317            bytelen = sizeof(long);
318            if (format[nn] == 'l') {
319                bytelen = sizeof(long long);
320                nn += 1;
321            }
322            c = format[nn++];
323            break;
324        case 'z':
325            bytelen = sizeof(size_t);
326            c = format[nn++];
327            break;
328        case 't':
329            bytelen = sizeof(ptrdiff_t);
330            c = format[nn++];
331            break;
332        default:
333            ;
334        }
335
336        /* conversion specifier */
337        const char* str = buffer;
338        if (c == 's') {
339            /* string */
340            str = va_arg(args, const char*);
341            if (str == NULL) {
342                str = "(null)";
343            }
344        } else if (c == 'c') {
345            /* character */
346            /* NOTE: char is promoted to int when passed through the stack */
347            buffer[0] = static_cast<char>(va_arg(args, int));
348            buffer[1] = '\0';
349        } else if (c == 'p') {
350            uint64_t  value = reinterpret_cast<uintptr_t>(va_arg(args, void*));
351            buffer[0] = '0';
352            buffer[1] = 'x';
353            format_integer(buffer + 2, sizeof(buffer) - 2, value, 'x');
354        } else if (c == 'd' || c == 'i' || c == 'o' || c == 'u' || c == 'x' || c == 'X') {
355            /* integers - first read value from stack */
356            uint64_t value;
357            int is_signed = (c == 'd' || c == 'i' || c == 'o');
358
359            /* NOTE: int8_t and int16_t are promoted to int when passed
360             *       through the stack
361             */
362            switch (bytelen) {
363            case 1: value = static_cast<uint8_t>(va_arg(args, int)); break;
364            case 2: value = static_cast<uint16_t>(va_arg(args, int)); break;
365            case 4: value = va_arg(args, uint32_t); break;
366            case 8: value = va_arg(args, uint64_t); break;
367            default: return;  /* should not happen */
368            }
369
370            /* sign extension, if needed */
371            if (is_signed) {
372                int shift = 64 - 8*bytelen;
373                value = static_cast<uint64_t>((static_cast<int64_t>(value << shift)) >> shift);
374            }
375
376            /* format the number properly into our buffer */
377            format_integer(buffer, sizeof(buffer), value, c);
378        } else if (c == '%') {
379            buffer[0] = '%';
380            buffer[1] = '\0';
381        } else {
382            __assert(__FILE__, __LINE__, "conversion specifier unsupported");
383        }
384
385        /* if we are here, 'str' points to the content that must be
386         * outputted. handle padding and alignment now */
387
388        slen = strlen(str);
389
390        if (sign != '\0' || prec != -1) {
391            __assert(__FILE__, __LINE__, "sign/precision unsupported");
392        }
393
394        if (slen < width && !padLeft) {
395            char padChar = padZero ? '0' : ' ';
396            SendRepeat(o, padChar, width - slen);
397        }
398
399        o.Send(str, slen);
400
401        if (slen < width && padLeft) {
402            char padChar = padZero ? '0' : ' ';
403            SendRepeat(o, padChar, width - slen);
404        }
405    }
406}
407
408int __libc_format_buffer(char* buffer, size_t buffer_size, const char* format, ...) {
409  BufferOutputStream os(buffer, buffer_size);
410  va_list args;
411  va_start(args, format);
412  out_vformat(os, format, args);
413  va_end(args);
414  return os.total;
415}
416
417int __libc_format_fd(int fd, const char* format, ...) {
418  FdOutputStream os(fd);
419  va_list args;
420  va_start(args, format);
421  out_vformat(os, format, args);
422  va_end(args);
423  return os.total;
424}
425
426static int __libc_write_stderr(const char* tag, const char* msg) {
427  int fd = TEMP_FAILURE_RETRY(open("/dev/stderr", O_CLOEXEC | O_WRONLY));
428  if (fd == -1) {
429    return -1;
430  }
431
432  iovec vec[4];
433  vec[0].iov_base = const_cast<char*>(tag);
434  vec[0].iov_len = strlen(tag);
435  vec[1].iov_base = const_cast<char*>(": ");
436  vec[1].iov_len = 2;
437  vec[2].iov_base = const_cast<char*>(msg);
438  vec[2].iov_len = strlen(msg) + 1;
439  vec[3].iov_base = const_cast<char*>("\n");
440  vec[3].iov_len = 1;
441
442  int result = TEMP_FAILURE_RETRY(writev(fd, vec, 4));
443  close(fd);
444  return result;
445}
446
447#ifdef TARGET_USES_LOGD
448static int __libc_open_log_socket()
449{
450  // ToDo: Ideally we want this to fail if the gid of the current
451  // process is AID_LOGD, but will have to wait until we have
452  // registered this in private/android_filesystem_config.h. We have
453  // found that all logd crashes thus far have had no problem stuffing
454  // the UNIX domain socket and moving on so not critical *today*.
455
456  int log_fd = TEMP_FAILURE_RETRY(socket(PF_UNIX, SOCK_DGRAM, 0));
457  if (log_fd < 0) {
458    return -1;
459  }
460
461  if (fcntl(log_fd, F_SETFL, O_NONBLOCK) == -1) {
462    close(log_fd);
463    return -1;
464  }
465
466  union {
467    struct sockaddr    addr;
468    struct sockaddr_un addrUn;
469  } u;
470  memset(&u, 0, sizeof(u));
471  u.addrUn.sun_family = AF_UNIX;
472  strlcpy(u.addrUn.sun_path, "/dev/socket/logdw", sizeof(u.addrUn.sun_path));
473
474  if (TEMP_FAILURE_RETRY(connect(log_fd, &u.addr, sizeof(u.addrUn))) != 0) {
475    close(log_fd);
476    return -1;
477  }
478
479  return log_fd;
480}
481
482struct log_time { // Wire format
483  uint32_t tv_sec;
484  uint32_t tv_nsec;
485};
486#endif
487
488static int __libc_write_log(int priority, const char* tag, const char* msg) {
489#ifdef TARGET_USES_LOGD
490  int main_log_fd = __libc_open_log_socket();
491
492  if (main_log_fd == -1) {
493    // Try stderr instead.
494    return __libc_write_stderr(tag, msg);
495  }
496
497  iovec vec[6];
498  char log_id = LOG_ID_MAIN;
499  vec[0].iov_base = &log_id;
500  vec[0].iov_len = sizeof(log_id);
501  uint16_t tid = gettid();
502  vec[1].iov_base = &tid;
503  vec[1].iov_len = sizeof(tid);
504  timespec ts;
505  clock_gettime(CLOCK_REALTIME, &ts);
506  log_time realtime_ts;
507  realtime_ts.tv_sec = ts.tv_sec;
508  realtime_ts.tv_nsec = ts.tv_nsec;
509  vec[2].iov_base = &realtime_ts;
510  vec[2].iov_len = sizeof(realtime_ts);
511
512  vec[3].iov_base = &priority;
513  vec[3].iov_len = 1;
514  vec[4].iov_base = const_cast<char*>(tag);
515  vec[4].iov_len = strlen(tag) + 1;
516  vec[5].iov_base = const_cast<char*>(msg);
517  vec[5].iov_len = strlen(msg) + 1;
518#else
519  int main_log_fd = TEMP_FAILURE_RETRY(open("/dev/log/main", O_CLOEXEC | O_WRONLY));
520  if (main_log_fd == -1) {
521    if (errno == ENOTDIR) {
522      // /dev/log isn't a directory? Maybe we're running on the host? Try stderr instead.
523      return __libc_write_stderr(tag, msg);
524    }
525    return -1;
526  }
527
528  iovec vec[3];
529  vec[0].iov_base = &priority;
530  vec[0].iov_len = 1;
531  vec[1].iov_base = const_cast<char*>(tag);
532  vec[1].iov_len = strlen(tag) + 1;
533  vec[2].iov_base = const_cast<char*>(msg);
534  vec[2].iov_len = strlen(msg) + 1;
535#endif
536
537  int result = TEMP_FAILURE_RETRY(writev(main_log_fd, vec, sizeof(vec) / sizeof(vec[0])));
538  close(main_log_fd);
539  return result;
540}
541
542int __libc_format_log_va_list(int priority, const char* tag, const char* format, va_list args) {
543  char buffer[1024];
544  BufferOutputStream os(buffer, sizeof(buffer));
545  out_vformat(os, format, args);
546  return __libc_write_log(priority, tag, buffer);
547}
548
549int __libc_format_log(int priority, const char* tag, const char* format, ...) {
550  va_list args;
551  va_start(args, format);
552  int result = __libc_format_log_va_list(priority, tag, format, args);
553  va_end(args);
554  return result;
555}
556
557static int __libc_android_log_event(int32_t tag, char type, const void* payload, size_t len) {
558#ifdef TARGET_USES_LOGD
559  iovec vec[6];
560  char log_id = LOG_ID_EVENTS;
561  vec[0].iov_base = &log_id;
562  vec[0].iov_len = sizeof(log_id);
563  uint16_t tid = gettid();
564  vec[1].iov_base = &tid;
565  vec[1].iov_len = sizeof(tid);
566  timespec ts;
567  clock_gettime(CLOCK_REALTIME, &ts);
568  log_time realtime_ts;
569  realtime_ts.tv_sec = ts.tv_sec;
570  realtime_ts.tv_nsec = ts.tv_nsec;
571  vec[2].iov_base = &realtime_ts;
572  vec[2].iov_len = sizeof(realtime_ts);
573
574  vec[3].iov_base = &tag;
575  vec[3].iov_len = sizeof(tag);
576  vec[4].iov_base = &type;
577  vec[4].iov_len = sizeof(type);
578  vec[5].iov_base = const_cast<void*>(payload);
579  vec[5].iov_len = len;
580
581  int event_log_fd = __libc_open_log_socket();
582#else
583  iovec vec[3];
584  vec[0].iov_base = &tag;
585  vec[0].iov_len = sizeof(tag);
586  vec[1].iov_base = &type;
587  vec[1].iov_len = sizeof(type);
588  vec[2].iov_base = const_cast<void*>(payload);
589  vec[2].iov_len = len;
590
591  int event_log_fd = TEMP_FAILURE_RETRY(open("/dev/log/events", O_CLOEXEC | O_WRONLY));
592#endif
593
594  if (event_log_fd == -1) {
595    return -1;
596  }
597  int result = TEMP_FAILURE_RETRY(writev(event_log_fd, vec, sizeof(vec) / sizeof(vec[0])));
598  close(event_log_fd);
599  return result;
600}
601
602void __libc_android_log_event_int(int32_t tag, int value) {
603  __libc_android_log_event(tag, EVENT_TYPE_INT, &value, sizeof(value));
604}
605
606void __libc_android_log_event_uid(int32_t tag) {
607  __libc_android_log_event_int(tag, getuid());
608}
609
610void __fortify_chk_fail(const char* msg, uint32_t tag) {
611  if (tag != 0) {
612    __libc_android_log_event_uid(tag);
613  }
614  __libc_fatal("FORTIFY_SOURCE: %s. Calling abort().", msg);
615}
616
617static void __libc_fatal(const char* format, va_list args) {
618  char msg[1024];
619  BufferOutputStream os(msg, sizeof(msg));
620  out_vformat(os, format, args);
621
622  // TODO: log to stderr for the benefit of "adb shell" users.
623
624  // Log to the log for the benefit of regular app developers (whose stdout and stderr are closed).
625  __libc_write_log(ANDROID_LOG_FATAL, "libc", msg);
626
627  __android_set_abort_message(msg);
628}
629
630void __libc_fatal_no_abort(const char* format, ...) {
631  va_list args;
632  va_start(args, format);
633  __libc_fatal(format, args);
634  va_end(args);
635}
636
637void __libc_fatal(const char* format, ...) {
638  va_list args;
639  va_start(args, format);
640  __libc_fatal(format, args);
641  va_end(args);
642  abort();
643}
644
645void __android_set_abort_message(const char* msg) {
646  ScopedPthreadMutexLocker locker(&gAbortMsgLock);
647
648  if (__abort_message_ptr == NULL) {
649    // We must have crashed _very_ early.
650    return;
651  }
652
653  if (*__abort_message_ptr != NULL) {
654    // We already have an abort message.
655    // Assume that the first crash is the one most worth reporting.
656    return;
657  }
658
659  size_t size = sizeof(abort_msg_t) + strlen(msg) + 1;
660  void* map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
661  if (map == MAP_FAILED) {
662    return;
663  }
664
665  // TODO: if we stick to the current "one-shot" scheme, we can remove this code and
666  // stop storing the size.
667  if (*__abort_message_ptr != NULL) {
668    munmap(*__abort_message_ptr, (*__abort_message_ptr)->size);
669  }
670  abort_msg_t* new_abort_message = reinterpret_cast<abort_msg_t*>(map);
671  new_abort_message->size = size;
672  strcpy(new_abort_message->msg, msg);
673  *__abort_message_ptr = new_abort_message;
674}
675