about summary refs log tree commit diff
path: root/third_party/glog/src/logging.cc
blob: ddcf91007358f0857da6fb530e0a4c5adfb524c6 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
// Copyright (c) 1999, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#define _GNU_SOURCE 1 // needed for O_NOFOLLOW and pread()/pwrite()

#include "utilities.h"

#include <algorithm>
#include <assert.h>
#include <iomanip>
#include <string>
#ifdef HAVE_UNISTD_H
# include <unistd.h>  // For _exit.
#endif
#include <climits>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_SYS_UTSNAME_H
# include <sys/utsname.h>  // For uname.
#endif
#include <time.h>
#include <fcntl.h>
#include <cstdio>
#include <iostream>
#include <stdarg.h>
#include <stdlib.h>
#ifdef HAVE_PWD_H
# include <pwd.h>
#endif
#ifdef HAVE_SYSLOG_H
# include <syslog.h>
#endif
#include <vector>
#include <errno.h>                   // for errno
#include <sstream>
#ifdef OS_WINDOWS
#include "windows/dirent.h"
#else
#include <dirent.h> // for automatic removal of old logs
#endif
#include "base/commandlineflags.h"        // to get the program name
#include "glog/logging.h"
#include "glog/raw_logging.h"
#include "base/googleinit.h"

#ifdef HAVE_STACKTRACE
# include "stacktrace.h"
#endif

using std::string;
using std::vector;
using std::setw;
using std::setfill;
using std::hex;
using std::dec;
using std::min;
using std::ostream;
using std::ostringstream;

using std::FILE;
using std::fwrite;
using std::fclose;
using std::fflush;
using std::fprintf;
using std::perror;

#ifdef __QNX__
using std::fdopen;
#endif

#ifdef _WIN32
#define fdopen _fdopen
#endif

// There is no thread annotation support.
#define EXCLUSIVE_LOCKS_REQUIRED(mu)

static bool BoolFromEnv(const char *varname, bool defval) {
  const char* const valstr = getenv(varname);
  if (!valstr) {
    return defval;
  }
  return memchr("tTyY1\0", valstr[0], 6) != NULL;
}

GLOG_DEFINE_bool(timestamp_in_logfile_name,
                 BoolFromEnv("GOOGLE_TIMESTAMP_IN_LOGFILE_NAME", true),
                 "put a timestamp at the end of the log file name");
GLOG_DEFINE_bool(logtostderr, BoolFromEnv("GOOGLE_LOGTOSTDERR", false),
                 "log messages go to stderr instead of logfiles");
GLOG_DEFINE_bool(alsologtostderr, BoolFromEnv("GOOGLE_ALSOLOGTOSTDERR", false),
                 "log messages go to stderr in addition to logfiles");
GLOG_DEFINE_bool(colorlogtostderr, false,
                 "color messages logged to stderr (if supported by terminal)");
#ifdef OS_LINUX
GLOG_DEFINE_bool(drop_log_memory, true, "Drop in-memory buffers of log contents. "
                 "Logs can grow very quickly and they are rarely read before they "
                 "need to be evicted from memory. Instead, drop them from memory "
                 "as soon as they are flushed to disk.");
#endif

// By default, errors (including fatal errors) get logged to stderr as
// well as the file.
//
// The default is ERROR instead of FATAL so that users can see problems
// when they run a program without having to look in another file.
DEFINE_int32(stderrthreshold,
             GOOGLE_NAMESPACE::GLOG_ERROR,
             "log messages at or above this level are copied to stderr in "
             "addition to logfiles.  This flag obsoletes --alsologtostderr.");

GLOG_DEFINE_string(alsologtoemail, "",
                   "log messages go to these email addresses "
                   "in addition to logfiles");
GLOG_DEFINE_bool(log_prefix, true,
                 "Prepend the log prefix to the start of each log line");
GLOG_DEFINE_int32(minloglevel, 0, "Messages logged at a lower level than this don't "
                  "actually get logged anywhere");
GLOG_DEFINE_int32(logbuflevel, 0,
                  "Buffer log messages logged at this level or lower"
                  " (-1 means don't buffer; 0 means buffer INFO only;"
                  " ...)");
GLOG_DEFINE_int32(logbufsecs, 30,
                  "Buffer log messages for at most this many seconds");
GLOG_DEFINE_int32(logemaillevel, 999,
                  "Email log messages logged at this level or higher"
                  " (0 means email all; 3 means email FATAL only;"
                  " ...)");
GLOG_DEFINE_string(logmailer, "/bin/mail",
                   "Mailer used to send logging email");

// Compute the default value for --log_dir
static const char* DefaultLogDir() {
  const char* env;
  env = getenv("GOOGLE_LOG_DIR");
  if (env != NULL && env[0] != '\0') {
    return env;
  }
  env = getenv("TEST_TMPDIR");
  if (env != NULL && env[0] != '\0') {
    return env;
  }
  return "";
}

GLOG_DEFINE_int32(logfile_mode, 0664, "Log file mode/permissions.");

GLOG_DEFINE_string(log_dir, DefaultLogDir(),
                   "If specified, logfiles are written into this directory instead "
                   "of the default logging directory.");
GLOG_DEFINE_string(log_link, "", "Put additional links to the log "
                   "files in this directory");

GLOG_DEFINE_int32(max_log_size, 1800,
                  "approx. maximum log file size (in MB). A value of 0 will "
                  "be silently overridden to 1.");

GLOG_DEFINE_bool(stop_logging_if_full_disk, false,
                 "Stop attempting to log to disk if the disk is full.");

GLOG_DEFINE_string(log_backtrace_at, "",
                   "Emit a backtrace when logging at file:linenum.");

// TODO(hamaji): consider windows
#define PATH_SEPARATOR '/'

#ifndef HAVE_PREAD
#if defined(OS_WINDOWS)
#include <basetsd.h>
#define ssize_t SSIZE_T
#endif
static ssize_t pread(int fd, void* buf, size_t count, off_t offset) {
  off_t orig_offset = lseek(fd, 0, SEEK_CUR);
  if (orig_offset == (off_t)-1)
    return -1;
  if (lseek(fd, offset, SEEK_CUR) == (off_t)-1)
    return -1;
  ssize_t len = read(fd, buf, count);
  if (len < 0)
    return len;
  if (lseek(fd, orig_offset, SEEK_SET) == (off_t)-1)
    return -1;
  return len;
}
#endif  // !HAVE_PREAD

#ifndef HAVE_PWRITE
static ssize_t pwrite(int fd, void* buf, size_t count, off_t offset) {
  off_t orig_offset = lseek(fd, 0, SEEK_CUR);
  if (orig_offset == (off_t)-1)
    return -1;
  if (lseek(fd, offset, SEEK_CUR) == (off_t)-1)
    return -1;
  ssize_t len = write(fd, buf, count);
  if (len < 0)
    return len;
  if (lseek(fd, orig_offset, SEEK_SET) == (off_t)-1)
    return -1;
  return len;
}
#endif  // !HAVE_PWRITE

static void GetHostName(string* hostname) {
#if defined(HAVE_SYS_UTSNAME_H)
  struct utsname buf;
  if (0 != uname(&buf)) {
    // ensure null termination on failure
    *buf.nodename = '\0';
  }
  *hostname = buf.nodename;
#elif defined(OS_WINDOWS)
  char buf[MAX_COMPUTERNAME_LENGTH + 1];
  DWORD len = MAX_COMPUTERNAME_LENGTH + 1;
  if (GetComputerNameA(buf, &len)) {
    *hostname = buf;
  } else {
    hostname->clear();
  }
#else
# warning There is no way to retrieve the host name.
  *hostname = "(unknown)";
#endif
}

// Returns true iff terminal supports using colors in output.
static bool TerminalSupportsColor() {
  bool term_supports_color = false;
#ifdef OS_WINDOWS
  // on Windows TERM variable is usually not set, but the console does
  // support colors.
  term_supports_color = true;
#else
  // On non-Windows platforms, we rely on the TERM variable.
  const char* const term = getenv("TERM");
  if (term != NULL && term[0] != '\0') {
    term_supports_color =
      !strcmp(term, "xterm") ||
      !strcmp(term, "xterm-color") ||
      !strcmp(term, "xterm-256color") ||
      !strcmp(term, "screen-256color") ||
      !strcmp(term, "konsole") ||
      !strcmp(term, "konsole-16color") ||
      !strcmp(term, "konsole-256color") ||
      !strcmp(term, "screen") ||
      !strcmp(term, "linux") ||
      !strcmp(term, "cygwin");
  }
#endif
  return term_supports_color;
}

_START_GOOGLE_NAMESPACE_

enum GLogColor {
  COLOR_DEFAULT,
  COLOR_RED,
  COLOR_GREEN,
  COLOR_YELLOW
};

static GLogColor SeverityToColor(LogSeverity severity) {
  assert(severity >= 0 && severity < NUM_SEVERITIES);
  GLogColor color = COLOR_DEFAULT;
  switch (severity) {
  case GLOG_INFO:
    color = COLOR_DEFAULT;
    break;
  case GLOG_WARNING:
    color = COLOR_YELLOW;
    break;
  case GLOG_ERROR:
  case GLOG_FATAL:
    color = COLOR_RED;
    break;
  default:
    // should never get here.
    assert(false);
  }
  return color;
}

#ifdef OS_WINDOWS

// Returns the character attribute for the given color.
static WORD GetColorAttribute(GLogColor color) {
  switch (color) {
    case COLOR_RED:    return FOREGROUND_RED;
    case COLOR_GREEN:  return FOREGROUND_GREEN;
    case COLOR_YELLOW: return FOREGROUND_RED | FOREGROUND_GREEN;
    default:           return 0;
  }
}

#else

// Returns the ANSI color code for the given color.
static const char* GetAnsiColorCode(GLogColor color) {
  switch (color) {
  case COLOR_RED:     return "1";
  case COLOR_GREEN:   return "2";
  case COLOR_YELLOW:  return "3";
  case COLOR_DEFAULT:  return "";
  };
  return NULL; // stop warning about return type.
}

#endif  // OS_WINDOWS

// Safely get max_log_size, overriding to 1 if it somehow gets defined as 0
static int32 MaxLogSize() {
  return (FLAGS_max_log_size > 0 ? FLAGS_max_log_size : 1);
}

// An arbitrary limit on the length of a single log message.  This
// is so that streaming can be done more efficiently.
const size_t LogMessage::kMaxLogMessageLen = 30000;

struct LogMessage::LogMessageData  {
  LogMessageData();

  int preserved_errno_;      // preserved errno
  // Buffer space; contains complete message text.
  char message_text_[LogMessage::kMaxLogMessageLen+1];
  LogStream stream_;
  char severity_;      // What level is this LogMessage logged at?
  int line_;                 // line number where logging call is.
  void (LogMessage::*send_method_)();  // Call this in destructor to send
  union {  // At most one of these is used: union to keep the size low.
    LogSink* sink_;             // NULL or sink to send message to
    std::vector<std::string>* outvec_; // NULL or vector to push message onto
    std::string* message_;             // NULL or string to write message into
  };
  time_t timestamp_;            // Time of creation of LogMessage
  struct ::tm tm_time_;         // Time of creation of LogMessage
  int32 usecs_;                   // Time of creation of LogMessage - microseconds part
  size_t num_prefix_chars_;     // # of chars of prefix in this message
  size_t num_chars_to_log_;     // # of chars of msg to send to log
  size_t num_chars_to_syslog_;  // # of chars of msg to send to syslog
  const char* basename_;        // basename of file that called LOG
  const char* fullname_;        // fullname of file that called LOG
  bool has_been_flushed_;       // false => data has not been flushed
  bool first_fatal_;            // true => this was first fatal msg

 private:
  LogMessageData(const LogMessageData&);
  void operator=(const LogMessageData&);
};

// A mutex that allows only one thread to log at a time, to keep things from
// getting jumbled.  Some other very uncommon logging operations (like
// changing the destination file for log messages of a given severity) also
// lock this mutex.  Please be sure that anybody who might possibly need to
// lock it does so.
static Mutex log_mutex;

// Number of messages sent at each severity.  Under log_mutex.
int64 LogMessage::num_messages_[NUM_SEVERITIES] = {0, 0, 0, 0};

// Globally disable log writing (if disk is full)
static bool stop_writing = false;

const char*const LogSeverityNames[NUM_SEVERITIES] = {
  "INFO", "WARNING", "ERROR", "FATAL"
};

// Has the user called SetExitOnDFatal(true)?
static bool exit_on_dfatal = true;

const char* GetLogSeverityName(LogSeverity severity) {
  return LogSeverityNames[severity];
}

static bool SendEmailInternal(const char*dest, const char *subject,
                              const char*body, bool use_logging);

base::Logger::~Logger() {
}

namespace {

// Encapsulates all file-system related state
class LogFileObject : public base::Logger {
 public:
  LogFileObject(LogSeverity severity, const char* base_filename);
  ~LogFileObject();

  virtual void Write(bool force_flush, // Should we force a flush here?
                     time_t timestamp,  // Timestamp for this entry
                     const char* message,
                     int message_len);

  // Configuration options
  void SetBasename(const char* basename);
  void SetExtension(const char* ext);
  void SetSymlinkBasename(const char* symlink_basename);

  // Normal flushing routine
  virtual void Flush();

  // It is the actual file length for the system loggers,
  // i.e., INFO, ERROR, etc.
  virtual uint32 LogSize() {
    MutexLock l(&lock_);
    return file_length_;
  }

  // Internal flush routine.  Exposed so that FlushLogFilesUnsafe()
  // can avoid grabbing a lock.  Usually Flush() calls it after
  // acquiring lock_.
  void FlushUnlocked();

 private:
  static const uint32 kRolloverAttemptFrequency = 0x20;

  Mutex lock_;
  bool base_filename_selected_;
  string base_filename_;
  string symlink_basename_;
  string filename_extension_;     // option users can specify (eg to add port#)
  FILE* file_;
  LogSeverity severity_;
  uint32 bytes_since_flush_;
  uint32 dropped_mem_length_;
  uint32 file_length_;
  unsigned int rollover_attempt_;
  int64 next_flush_time_;         // cycle count at which to flush log

  // Actually create a logfile using the value of base_filename_ and the
  // optional argument time_pid_string
  // REQUIRES: lock_ is held
  bool CreateLogfile(const string& time_pid_string);
};

}  // namespace

class LogDestination {
 public:
  friend class LogMessage;
  friend void ReprintFatalMessage();
  friend base::Logger* base::GetLogger(LogSeverity);
  friend void base::SetLogger(LogSeverity, base::Logger*);

  // These methods are just forwarded to by their global versions.
  static void SetLogDestination(LogSeverity severity,
				const char* base_filename);
  static void SetLogSymlink(LogSeverity severity,
                            const char* symlink_basename);
  static void AddLogSink(LogSink *destination);
  static void RemoveLogSink(LogSink *destination);
  static void SetLogFilenameExtension(const char* filename_extension);
  static void SetStderrLogging(LogSeverity min_severity);
  static void SetEmailLogging(LogSeverity min_severity, const char* addresses);
  static void LogToStderr();
  // Flush all log files that are at least at the given severity level
  static void FlushLogFiles(int min_severity);
  static void FlushLogFilesUnsafe(int min_severity);

  // we set the maximum size of our packet to be 1400, the logic being
  // to prevent fragmentation.
  // Really this number is arbitrary.
  static const int kNetworkBytes = 1400;

  static const string& hostname();
  static const bool& terminal_supports_color() {
    return terminal_supports_color_;
  }

  static void DeleteLogDestinations();

 private:
  LogDestination(LogSeverity severity, const char* base_filename);
  ~LogDestination();

  // Take a log message of a particular severity and log it to stderr
  // iff it's of a high enough severity to deserve it.
  static void MaybeLogToStderr(LogSeverity severity, const char* message,
			       size_t len);

  // Take a log message of a particular severity and log it to email
  // iff it's of a high enough severity to deserve it.
  static void MaybeLogToEmail(LogSeverity severity, const char* message,
			      size_t len);
  // Take a log message of a particular severity and log it to a file
  // iff the base filename is not "" (which means "don't log to me")
  static void MaybeLogToLogfile(LogSeverity severity,
                                time_t timestamp,
				const char* message, size_t len);
  // Take a log message of a particular severity and log it to the file
  // for that severity and also for all files with severity less than
  // this severity.
  static void LogToAllLogfiles(LogSeverity severity,
                               time_t timestamp,
                               const char* message, size_t len);

  // Send logging info to all registered sinks.
  static void LogToSinks(LogSeverity severity,
                         const char *full_filename,
                         const char *base_filename,
                         int line,
                         const struct ::tm* tm_time,
                         const char* message,
                         size_t message_len,
                         int32 usecs);

  // Wait for all registered sinks via WaitTillSent
  // including the optional one in "data".
  static void WaitForSinks(LogMessage::LogMessageData* data);

  static LogDestination* log_destination(LogSeverity severity);

  LogFileObject fileobject_;
  base::Logger* logger_;      // Either &fileobject_, or wrapper around it

  static LogDestination* log_destinations_[NUM_SEVERITIES];
  static LogSeverity email_logging_severity_;
  static string addresses_;
  static string hostname_;
  static bool terminal_supports_color_;

  // arbitrary global logging destinations.
  static vector<LogSink*>* sinks_;

  // Protects the vector sinks_,
  // but not the LogSink objects its elements reference.
  static Mutex sink_mutex_;

  // Disallow
  LogDestination(const LogDestination&);
  LogDestination& operator=(const LogDestination&);
};

// Errors do not get logged to email by default.
LogSeverity LogDestination::email_logging_severity_ = 99999;

string LogDestination::addresses_;
string LogDestination::hostname_;

vector<LogSink*>* LogDestination::sinks_ = NULL;
Mutex LogDestination::sink_mutex_;
bool LogDestination::terminal_supports_color_ = TerminalSupportsColor();

/* static */
const string& LogDestination::hostname() {
  if (hostname_.empty()) {
    GetHostName(&hostname_);
    if (hostname_.empty()) {
      hostname_ = "(unknown)";
    }
  }
  return hostname_;
}

LogDestination::LogDestination(LogSeverity severity,
                               const char* base_filename)
  : fileobject_(severity, base_filename),
    logger_(&fileobject_) {
}

LogDestination::~LogDestination() {
  if (logger_ && logger_ != &fileobject_) {
    // Delete user-specified logger set via SetLogger().
    delete logger_;
  }
}

inline void LogDestination::FlushLogFilesUnsafe(int min_severity) {
  // assume we have the log_mutex or we simply don't care
  // about it
  for (int i = min_severity; i < NUM_SEVERITIES; i++) {
    LogDestination* log = log_destinations_[i];
    if (log != NULL) {
      // Flush the base fileobject_ logger directly instead of going
      // through any wrappers to reduce chance of deadlock.
      log->fileobject_.FlushUnlocked();
    }
  }
}

inline void LogDestination::FlushLogFiles(int min_severity) {
  // Prevent any subtle race conditions by wrapping a mutex lock around
  // all this stuff.
  MutexLock l(&log_mutex);
  for (int i = min_severity; i < NUM_SEVERITIES; i++) {
    LogDestination* log = log_destination(i);
    if (log != NULL) {
      log->logger_->Flush();
    }
  }
}

inline void LogDestination::SetLogDestination(LogSeverity severity,
					      const char* base_filename) {
  assert(severity >= 0 && severity < NUM_SEVERITIES);
  // Prevent any subtle race conditions by wrapping a mutex lock around
  // all this stuff.
  MutexLock l(&log_mutex);
  log_destination(severity)->fileobject_.SetBasename(base_filename);
}

inline void LogDestination::SetLogSymlink(LogSeverity severity,
                                          const char* symlink_basename) {
  CHECK_GE(severity, 0);
  CHECK_LT(severity, NUM_SEVERITIES);
  MutexLock l(&log_mutex);
  log_destination(severity)->fileobject_.SetSymlinkBasename(symlink_basename);
}

inline void LogDestination::AddLogSink(LogSink *destination) {
  // Prevent any subtle race conditions by wrapping a mutex lock around
  // all this stuff.
  MutexLock l(&sink_mutex_);
  if (!sinks_)  sinks_ = new vector<LogSink*>;
  sinks_->push_back(destination);
}

inline void LogDestination::RemoveLogSink(LogSink *destination) {
  // Prevent any subtle race conditions by wrapping a mutex lock around
  // all this stuff.
  MutexLock l(&sink_mutex_);
  // This doesn't keep the sinks in order, but who cares?
  if (sinks_) {
    for (int i = sinks_->size() - 1; i >= 0; i--) {
      if ((*sinks_)[i] == destination) {
        (*sinks_)[i] = (*sinks_)[sinks_->size() - 1];
        sinks_->pop_back();
        break;
      }
    }
  }
}

inline void LogDestination::SetLogFilenameExtension(const char* ext) {
  // Prevent any subtle race conditions by wrapping a mutex lock around
  // all this stuff.
  MutexLock l(&log_mutex);
  for ( int severity = 0; severity < NUM_SEVERITIES; ++severity ) {
    log_destination(severity)->fileobject_.SetExtension(ext);
  }
}

inline void LogDestination::SetStderrLogging(LogSeverity min_severity) {
  assert(min_severity >= 0 && min_severity < NUM_SEVERITIES);
  // Prevent any subtle race conditions by wrapping a mutex lock around
  // all this stuff.
  MutexLock l(&log_mutex);
  FLAGS_stderrthreshold = min_severity;
}

inline void LogDestination::LogToStderr() {
  // *Don't* put this stuff in a mutex lock, since SetStderrLogging &
  // SetLogDestination already do the locking!
  SetStderrLogging(0);            // thus everything is "also" logged to stderr
  for ( int i = 0; i < NUM_SEVERITIES; ++i ) {
    SetLogDestination(i, "");     // "" turns off logging to a logfile
  }
}

inline void LogDestination::SetEmailLogging(LogSeverity min_severity,
					    const char* addresses) {
  assert(min_severity >= 0 && min_severity < NUM_SEVERITIES);
  // Prevent any subtle race conditions by wrapping a mutex lock around
  // all this stuff.
  MutexLock l(&log_mutex);
  LogDestination::email_logging_severity_ = min_severity;
  LogDestination::addresses_ = addresses;
}

static void ColoredWriteToStderr(LogSeverity severity,
                                 const char* message, size_t len) {
  const GLogColor color =
      (LogDestination::terminal_supports_color() && FLAGS_colorlogtostderr) ?
      SeverityToColor(severity) : COLOR_DEFAULT;

  // Avoid using cerr from this module since we may get called during
  // exit code, and cerr may be partially or fully destroyed by then.
  if (COLOR_DEFAULT == color) {
    fwrite(message, len, 1, stderr);
    return;
  }
#ifdef OS_WINDOWS
  const HANDLE stderr_handle = GetStdHandle(STD_ERROR_HANDLE);

  // Gets the current text color.
  CONSOLE_SCREEN_BUFFER_INFO buffer_info;
  GetConsoleScreenBufferInfo(stderr_handle, &buffer_info);
  const WORD old_color_attrs = buffer_info.wAttributes;

  // We need to flush the stream buffers into the console before each
  // SetConsoleTextAttribute call lest it affect the text that is already
  // printed but has not yet reached the console.
  fflush(stderr);
  SetConsoleTextAttribute(stderr_handle,
                          GetColorAttribute(color) | FOREGROUND_INTENSITY);
  fwrite(message, len, 1, stderr);
  fflush(stderr);
  // Restores the text color.
  SetConsoleTextAttribute(stderr_handle, old_color_attrs);
#else
  fprintf(stderr, "\033[0;3%sm", GetAnsiColorCode(color));
  fwrite(message, len, 1, stderr);
  fprintf(stderr, "\033[m");  // Resets the terminal to default.
#endif  // OS_WINDOWS
}

static void WriteToStderr(const char* message, size_t len) {
  // Avoid using cerr from this module since we may get called during
  // exit code, and cerr may be partially or fully destroyed by then.
  fwrite(message, len, 1, stderr);
}

inline void LogDestination::MaybeLogToStderr(LogSeverity severity,
					     const char* message, size_t len) {
  if ((severity >= FLAGS_stderrthreshold) || FLAGS_alsologtostderr) {
    ColoredWriteToStderr(severity, message, len);
#ifdef OS_WINDOWS
    // On Windows, also output to the debugger
    ::OutputDebugStringA(string(message,len).c_str());
#endif
  }
}


inline void LogDestination::MaybeLogToEmail(LogSeverity severity,
					    const char* message, size_t len) {
  if (severity >= email_logging_severity_ ||
      severity >= FLAGS_logemaillevel) {
    string to(FLAGS_alsologtoemail);
    if (!addresses_.empty()) {
      if (!to.empty()) {
        to += ",";
      }
      to += addresses_;
    }
    const string subject(string("[LOG] ") + LogSeverityNames[severity] + ": " +
                         glog_internal_namespace_::ProgramInvocationShortName());
    string body(hostname());
    body += "\n\n";
    body.append(message, len);

    // should NOT use SendEmail().  The caller of this function holds the
    // log_mutex and SendEmail() calls LOG/VLOG which will block trying to
    // acquire the log_mutex object.  Use SendEmailInternal() and set
    // use_logging to false.
    SendEmailInternal(to.c_str(), subject.c_str(), body.c_str(), false);
  }
}


inline void LogDestination::MaybeLogToLogfile(LogSeverity severity,
                                              time_t timestamp,
					      const char* message,
					      size_t len) {
  const bool should_flush = severity > FLAGS_logbuflevel;
  LogDestination* destination = log_destination(severity);
  destination->logger_->Write(should_flush, timestamp, message, len);
}

inline void LogDestination::LogToAllLogfiles(LogSeverity severity,
                                             time_t timestamp,
                                             const char* message,
                                             size_t len) {

  if ( FLAGS_logtostderr ) {           // global flag: never log to file
    ColoredWriteToStderr(severity, message, len);
  } else {
    for (int i = severity; i >= 0; --i)
      LogDestination::MaybeLogToLogfile(i, timestamp, message, len);
  }
}

inline void LogDestination::LogToSinks(LogSeverity severity,
                                       const char *full_filename,
                                       const char *base_filename,
                                       int line,
                                       const struct ::tm* tm_time,
                                       const char* message,
                                       size_t message_len,
                                       int32 usecs) {
  ReaderMutexLock l(&sink_mutex_);
  if (sinks_) {
    for (int i = sinks_->size() - 1; i >= 0; i--) {
      (*sinks_)[i]->send(severity, full_filename, base_filename,
                         line, tm_time, message, message_len, usecs);
    }
  }
}

inline void LogDestination::WaitForSinks(LogMessage::LogMessageData* data) {
  ReaderMutexLock l(&sink_mutex_);
  if (sinks_) {
    for (int i = sinks_->size() - 1; i >= 0; i--) {
      (*sinks_)[i]->WaitTillSent();
    }
  }
  const bool send_to_sink =
      (data->send_method_ == &LogMessage::SendToSink) ||
      (data->send_method_ == &LogMessage::SendToSinkAndLog);
  if (send_to_sink && data->sink_ != NULL) {
    data->sink_->WaitTillSent();
  }
}

LogDestination* LogDestination::log_destinations_[NUM_SEVERITIES];

inline LogDestination* LogDestination::log_destination(LogSeverity severity) {
  assert(severity >=0 && severity < NUM_SEVERITIES);
  if (!log_destinations_[severity]) {
    log_destinations_[severity] = new LogDestination(severity, NULL);
  }
  return log_destinations_[severity];
}

void LogDestination::DeleteLogDestinations() {
  for (int severity = 0; severity < NUM_SEVERITIES; ++severity) {
    delete log_destinations_[severity];
    log_destinations_[severity] = NULL;
  }
  MutexLock l(&sink_mutex_);
  delete sinks_;
  sinks_ = NULL;
}

namespace {

bool IsGlogLog(const string& filename) {
  // Check if filename matches the pattern of a glog file:
  // "<program name>.<hostname>.<user name>.log...".
  const int kKeywordCount = 4;
  std::string keywords[kKeywordCount] = {
    glog_internal_namespace_::ProgramInvocationShortName(),
    LogDestination::hostname(),
    MyUserName(),
    "log"
  };

  int start_pos = 0;
  for (int i = 0; i < kKeywordCount; i++) {
    if (filename.find(keywords[i], start_pos) == filename.npos) {
      return false;
    }
    start_pos += keywords[i].size() + 1;
  }
  return true;
}

bool LastModifiedOver(const string& filepath, int days) {
  // Try to get the last modified time of this file.
  struct stat file_stat;

  if (stat(filepath.c_str(), &file_stat) == 0) {
    // A day is 86400 seconds, so 7 days is 86400 * 7 = 604800 seconds.
    time_t last_modified_time = file_stat.st_mtime;
    time_t current_time = time(NULL);
    return difftime(current_time, last_modified_time) > days * 86400;
  }

  // If failed to get file stat, don't return true!
  return false;
}

vector<string> GetOverdueLogNames(string log_directory, int days) {
  // The names of overdue logs.
  vector<string> overdue_log_names;

  // Try to get all files within log_directory.
  DIR *dir;
  struct dirent *ent;

  char dir_delim = '/';
#ifdef OS_WINDOWS
  dir_delim = '\\';
#endif

  // If log_directory doesn't end with a slash, append a slash to it.
  if (log_directory.at(log_directory.size() - 1) != dir_delim) {
    log_directory += dir_delim;
  }

  if ((dir=opendir(log_directory.c_str()))) {
    while ((ent=readdir(dir))) {
      if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, "..")) {
        continue;
      }
      string filepath = log_directory + ent->d_name;
      if (IsGlogLog(ent->d_name) && LastModifiedOver(filepath, days)) {
        overdue_log_names.push_back(filepath);
      }
    }
    closedir(dir);
  }

  return overdue_log_names;
}

// Is log_cleaner enabled?
// This option can be enabled by calling google::EnableLogCleaner(days)
bool log_cleaner_enabled_;
int log_cleaner_overdue_days_ = 7;

} // namespace


namespace {

LogFileObject::LogFileObject(LogSeverity severity,
                             const char* base_filename)
  : base_filename_selected_(base_filename != NULL),
    base_filename_((base_filename != NULL) ? base_filename : ""),
    symlink_basename_(glog_internal_namespace_::ProgramInvocationShortName()),
    filename_extension_(),
    file_(NULL),
    severity_(severity),
    bytes_since_flush_(0),
    dropped_mem_length_(0),
    file_length_(0),
    rollover_attempt_(kRolloverAttemptFrequency-1),
    next_flush_time_(0) {
  assert(severity >= 0);
  assert(severity < NUM_SEVERITIES);
}

LogFileObject::~LogFileObject() {
  MutexLock l(&lock_);
  if (file_ != NULL) {
    fclose(file_);
    file_ = NULL;
  }
}

void LogFileObject::SetBasename(const char* basename) {
  MutexLock l(&lock_);
  base_filename_selected_ = true;
  if (base_filename_ != basename) {
    // Get rid of old log file since we are changing names
    if (file_ != NULL) {
      fclose(file_);
      file_ = NULL;
      rollover_attempt_ = kRolloverAttemptFrequency-1;
    }
    base_filename_ = basename;
  }
}

void LogFileObject::SetExtension(const char* ext) {
  MutexLock l(&lock_);
  if (filename_extension_ != ext) {
    // Get rid of old log file since we are changing names
    if (file_ != NULL) {
      fclose(file_);
      file_ = NULL;
      rollover_attempt_ = kRolloverAttemptFrequency-1;
    }
    filename_extension_ = ext;
  }
}

void LogFileObject::SetSymlinkBasename(const char* symlink_basename) {
  MutexLock l(&lock_);
  symlink_basename_ = symlink_basename;
}

void LogFileObject::Flush() {
  MutexLock l(&lock_);
  FlushUnlocked();
}

void LogFileObject::FlushUnlocked(){
  if (file_ != NULL) {
    fflush(file_);
    bytes_since_flush_ = 0;
  }
  // Figure out when we are due for another flush.
  const int64 next = (FLAGS_logbufsecs
                      * static_cast<int64>(1000000));  // in usec
  next_flush_time_ = CycleClock_Now() + UsecToCycles(next);
}

bool LogFileObject::CreateLogfile(const string& time_pid_string) {
  string string_filename = base_filename_+filename_extension_;
  if (FLAGS_timestamp_in_logfile_name) {
    string_filename += time_pid_string;
  }
  const char* filename = string_filename.c_str();
  //only write to files, create if non-existant.
  int flags = O_WRONLY | O_CREAT;
  if (FLAGS_timestamp_in_logfile_name) {
    //demand that the file is unique for our timestamp (fail if it exists).
    flags = flags | O_EXCL;
  }
  int fd = open(filename, flags, FLAGS_logfile_mode);
  if (fd == -1) return false;
#ifdef HAVE_FCNTL
  // Mark the file close-on-exec. We don't really care if this fails
  fcntl(fd, F_SETFD, FD_CLOEXEC);

  // Mark the file as exclusive write access to avoid two clients logging to the
  // same file. This applies particularly when !FLAGS_timestamp_in_logfile_name
  // (otherwise open would fail because the O_EXCL flag on similar filename).
  // locks are released on unlock or close() automatically, only after log is
  // released.
  // This will work after a fork as it is not inherited (not stored in the fd).
  // Lock will not be lost because the file is opened with exclusive lock (write)
  // and we will never read from it inside the process.
  // TODO windows implementation of this (as flock is not available on mingw).
  static struct flock w_lock;

  w_lock.l_type = F_WRLCK;
  w_lock.l_start = 0;
  w_lock.l_whence = SEEK_SET;
  w_lock.l_len = 0;

  int wlock_ret = fcntl(fd, F_SETLK, &w_lock);
  if (wlock_ret == -1) {
      close(fd); //as we are failing already, do not check errors here
      return false;
  }
#endif

  //fdopen in append mode so if the file exists it will fseek to the end
  file_ = fdopen(fd, "a");  // Make a FILE*.
  if (file_ == NULL) {  // Man, we're screwed!
    close(fd);
    if (FLAGS_timestamp_in_logfile_name) {
      unlink(filename);  // Erase the half-baked evidence: an unusable log file, only if we just created it.
    }
    return false;
  }
#ifdef OS_WINDOWS
  // https://github.com/golang/go/issues/27638 - make sure we seek to the end to append
  // empirically replicated with wine over mingw build
  if (!FLAGS_timestamp_in_logfile_name) {
    if (fseek(file_, 0, SEEK_END) != 0) {
      return false;
    }
  }
#endif
  // We try to create a symlink called <program_name>.<severity>,
  // which is easier to use.  (Every time we create a new logfile,
  // we destroy the old symlink and create a new one, so it always
  // points to the latest logfile.)  If it fails, we're sad but it's
  // no error.
  if (!symlink_basename_.empty()) {
    // take directory from filename
    const char* slash = strrchr(filename, PATH_SEPARATOR);
    const string linkname =
      symlink_basename_ + '.' + LogSeverityNames[severity_];
    string linkpath;
    if ( slash ) linkpath = string(filename, slash-filename+1);  // get dirname
    linkpath += linkname;
    unlink(linkpath.c_str());                    // delete old one if it exists

#if defined(OS_WINDOWS)
    // TODO(hamaji): Create lnk file on Windows?
#elif defined(HAVE_UNISTD_H)
    // We must have unistd.h.
    // Make the symlink be relative (in the same dir) so that if the
    // entire log directory gets relocated the link is still valid.
    const char *linkdest = slash ? (slash + 1) : filename;
    if (symlink(linkdest, linkpath.c_str()) != 0) {
      // silently ignore failures
    }

    // Make an additional link to the log file in a place specified by
    // FLAGS_log_link, if indicated
    if (!FLAGS_log_link.empty()) {
      linkpath = FLAGS_log_link + "/" + linkname;
      unlink(linkpath.c_str());                  // delete old one if it exists
      if (symlink(filename, linkpath.c_str()) != 0) {
        // silently ignore failures
      }
    }
#endif
  }

  return true;  // Everything worked
}

void LogFileObject::Write(bool force_flush,
                          time_t timestamp,
                          const char* message,
                          int message_len) {
  MutexLock l(&lock_);

  // We don't log if the base_name_ is "" (which means "don't write")
  if (base_filename_selected_ && base_filename_.empty()) {
    return;
  }

  if (static_cast<int>(file_length_ >> 20) >= MaxLogSize() ||
      PidHasChanged()) {
    if (file_ != NULL) fclose(file_);
    file_ = NULL;
    file_length_ = bytes_since_flush_ = dropped_mem_length_ = 0;
    rollover_attempt_ = kRolloverAttemptFrequency-1;
  }

  // If there's no destination file, make one before outputting
  if (file_ == NULL) {
    // Try to rollover the log file every 32 log messages.  The only time
    // this could matter would be when we have trouble creating the log
    // file.  If that happens, we'll lose lots of log messages, of course!
    if (++rollover_attempt_ != kRolloverAttemptFrequency) return;
    rollover_attempt_ = 0;

    struct ::tm tm_time;
    localtime_r(&timestamp, &tm_time);

    // The logfile's filename will have the date/time & pid in it
    ostringstream time_pid_stream;
    time_pid_stream.fill('0');
    time_pid_stream << 1900+tm_time.tm_year
                    << setw(2) << 1+tm_time.tm_mon
                    << setw(2) << tm_time.tm_mday
                    << '-'
                    << setw(2) << tm_time.tm_hour
                    << setw(2) << tm_time.tm_min
                    << setw(2) << tm_time.tm_sec
                    << '.'
                    << GetMainThreadPid();
    const string& time_pid_string = time_pid_stream.str();

    if (base_filename_selected_) {
      if (!CreateLogfile(time_pid_string)) {
        perror("Could not create log file");
        fprintf(stderr, "COULD NOT CREATE LOGFILE '%s'!\n",
                time_pid_string.c_str());
        return;
      }
    } else {
      // If no base filename for logs of this severity has been set, use a
      // default base filename of
      // "<program name>.<hostname>.<user name>.log.<severity level>.".  So
      // logfiles will have names like
      // webserver.examplehost.root.log.INFO.19990817-150000.4354, where
      // 19990817 is a date (1999 August 17), 150000 is a time (15:00:00),
      // and 4354 is the pid of the logging process.  The date & time reflect
      // when the file was created for output.
      //
      // Where does the file get put?  Successively try the directories
      // "/tmp", and "."
      string stripped_filename(
          glog_internal_namespace_::ProgramInvocationShortName());
      string hostname;
      GetHostName(&hostname);

      string uidname = MyUserName();
      // We should not call CHECK() here because this function can be
      // called after holding on to log_mutex. We don't want to
      // attempt to hold on to the same mutex, and get into a
      // deadlock. Simply use a name like invalid-user.
      if (uidname.empty()) uidname = "invalid-user";

      stripped_filename = stripped_filename+'.'+hostname+'.'
                          +uidname+".log."
                          +LogSeverityNames[severity_]+'.';
      // We're going to (potentially) try to put logs in several different dirs
      const vector<string> & log_dirs = GetLoggingDirectories();

      // Go through the list of dirs, and try to create the log file in each
      // until we succeed or run out of options
      bool success = false;
      for (vector<string>::const_iterator dir = log_dirs.begin();
           dir != log_dirs.end();
           ++dir) {
        base_filename_ = *dir + "/" + stripped_filename;
        if ( CreateLogfile(time_pid_string) ) {
          success = true;
          break;
        }
      }
      // If we never succeeded, we have to give up
      if ( success == false ) {
        perror("Could not create logging file");
        fprintf(stderr, "COULD NOT CREATE A LOGGINGFILE %s!",
                time_pid_string.c_str());
        return;
      }
    }

    // Write a header message into the log file
    ostringstream file_header_stream;
    file_header_stream.fill('0');
    file_header_stream << "Log file created at: "
                       << 1900+tm_time.tm_year << '/'
                       << setw(2) << 1+tm_time.tm_mon << '/'
                       << setw(2) << tm_time.tm_mday
                       << ' '
                       << setw(2) << tm_time.tm_hour << ':'
                       << setw(2) << tm_time.tm_min << ':'
                       << setw(2) << tm_time.tm_sec << '\n'
                       << "Running on machine: "
                       << LogDestination::hostname() << '\n'
                       << "Log line format: [IWEF]yyyymmdd hh:mm:ss.uuuuuu "
                       << "threadid file:line] msg" << '\n';
    const string& file_header_string = file_header_stream.str();

    const int header_len = file_header_string.size();
    fwrite(file_header_string.data(), 1, header_len, file_);
    file_length_ += header_len;
    bytes_since_flush_ += header_len;
  }
 
  // Write to LOG file
  if ( !stop_writing ) {
    // fwrite() doesn't return an error when the disk is full, for
    // messages that are less than 4096 bytes. When the disk is full,
    // it returns the message length for messages that are less than
    // 4096 bytes. fwrite() returns 4096 for message lengths that are
    // greater than 4096, thereby indicating an error.
    errno = 0;
    fwrite(message, 1, message_len, file_);
    if ( FLAGS_stop_logging_if_full_disk &&
         errno == ENOSPC ) {  // disk full, stop writing to disk
      stop_writing = true;  // until the disk is
      return;
    } else {
      file_length_ += message_len;
      bytes_since_flush_ += message_len;
    }
  } else {
    if ( CycleClock_Now() >= next_flush_time_ )
      stop_writing = false;  // check to see if disk has free space.
    return;  // no need to flush
  }

  // See important msgs *now*.  Also, flush logs at least every 10^6 chars,
  // or every "FLAGS_logbufsecs" seconds.
  if ( force_flush ||
       (bytes_since_flush_ >= 1000000) ||
       (CycleClock_Now() >= next_flush_time_) ) {
    FlushUnlocked();
#ifdef OS_LINUX
    // Only consider files >= 3MiB
    if (FLAGS_drop_log_memory && file_length_ >= (3 << 20)) {
      // Don't evict the most recent 1-2MiB so as not to impact a tailer
      // of the log file and to avoid page rounding issue on linux < 4.7
      uint32 total_drop_length = (file_length_ & ~((1 << 20) - 1)) - (1 << 20);
      uint32 this_drop_length = total_drop_length - dropped_mem_length_;
      if (this_drop_length >= (2 << 20)) {
        // Only advise when >= 2MiB to drop
# if defined(__ANDROID__) && defined(__ANDROID_API__) && (__ANDROID_API__ < 21)
        // 'posix_fadvise' introduced in API 21:
        // * https://android.googlesource.com/platform/bionic/+/6880f936173081297be0dc12f687d341b86a4cfa/libc/libc.map.txt#732
# else
        posix_fadvise(fileno(file_), dropped_mem_length_, this_drop_length,
                      POSIX_FADV_DONTNEED);
# endif
        dropped_mem_length_ = total_drop_length;
      }
    }
#endif
    // Perform clean up for old logs
    if (log_cleaner_enabled_) {
      const vector<string>& dirs = GetLoggingDirectories();
      for (size_t i = 0; i < dirs.size(); i++) {
        vector<string> logs = GetOverdueLogNames(dirs[i], log_cleaner_overdue_days_);
        for (size_t j = 0; j < logs.size(); j++) {
          static_cast<void>(unlink(logs[j].c_str()));
        }
      }
    }
  }
}

}  // namespace

// Static log data space to avoid alloc failures in a LOG(FATAL)
//
// Since multiple threads may call LOG(FATAL), and we want to preserve
// the data from the first call, we allocate two sets of space.  One
// for exclusive use by the first thread, and one for shared use by
// all other threads.
static Mutex fatal_msg_lock;
static CrashReason crash_reason;
static bool fatal_msg_exclusive = true;
static LogMessage::LogMessageData fatal_msg_data_exclusive;
static LogMessage::LogMessageData fatal_msg_data_shared;

#ifdef GLOG_THREAD_LOCAL_STORAGE
// Static thread-local log data space to use, because typically at most one
// LogMessageData object exists (in this case glog makes zero heap memory
// allocations).
static GLOG_THREAD_LOCAL_STORAGE bool thread_data_available = true;

#ifdef HAVE_ALIGNED_STORAGE
static GLOG_THREAD_LOCAL_STORAGE
    std::aligned_storage<sizeof(LogMessage::LogMessageData),
                         alignof(LogMessage::LogMessageData)>::type thread_msg_data;
#else
static GLOG_THREAD_LOCAL_STORAGE
    char thread_msg_data[sizeof(void*) + sizeof(LogMessage::LogMessageData)];
#endif  // HAVE_ALIGNED_STORAGE
#endif  // defined(GLOG_THREAD_LOCAL_STORAGE)

LogMessage::LogMessageData::LogMessageData()
  : stream_(message_text_, LogMessage::kMaxLogMessageLen, 0) {
}

LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
                       int ctr, void (LogMessage::*send_method)())
    : allocated_(NULL) {
  Init(file, line, severity, send_method);
  data_->stream_.set_ctr(ctr);
}

LogMessage::LogMessage(const char* file, int line,
                       const CheckOpString& result)
    : allocated_(NULL) {
  Init(file, line, GLOG_FATAL, &LogMessage::SendToLog);
  stream() << "Check failed: " << (*result.str_) << " ";
}

LogMessage::LogMessage(const char* file, int line)
    : allocated_(NULL) {
  Init(file, line, GLOG_INFO, &LogMessage::SendToLog);
}

LogMessage::LogMessage(const char* file, int line, LogSeverity severity)
    : allocated_(NULL) {
  Init(file, line, severity, &LogMessage::SendToLog);
}

LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
                       LogSink* sink, bool also_send_to_log)
    : allocated_(NULL) {
  Init(file, line, severity, also_send_to_log ? &LogMessage::SendToSinkAndLog :
                                                &LogMessage::SendToSink);
  data_->sink_ = sink;  // override Init()'s setting to NULL
}

LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
                       vector<string> *outvec)
    : allocated_(NULL) {
  Init(file, line, severity, &LogMessage::SaveOrSendToLog);
  data_->outvec_ = outvec; // override Init()'s setting to NULL
}

LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
                       string *message)
    : allocated_(NULL) {
  Init(file, line, severity, &LogMessage::WriteToStringAndLog);
  data_->message_ = message;  // override Init()'s setting to NULL
}

void LogMessage::Init(const char* file,
                      int line,
                      LogSeverity severity,
                      void (LogMessage::*send_method)()) {
  allocated_ = NULL;
  if (severity != GLOG_FATAL || !exit_on_dfatal) {
#ifdef GLOG_THREAD_LOCAL_STORAGE
    // No need for locking, because this is thread local.
    if (thread_data_available) {
      thread_data_available = false;
#ifdef HAVE_ALIGNED_STORAGE
      data_ = new (&thread_msg_data) LogMessageData;
#else
      const uintptr_t kAlign = sizeof(void*) - 1;

      char* align_ptr =
          reinterpret_cast<char*>(reinterpret_cast<uintptr_t>(thread_msg_data + kAlign) & ~kAlign);
      data_ = new (align_ptr) LogMessageData;
      assert(reinterpret_cast<uintptr_t>(align_ptr) % sizeof(void*) == 0);
#endif
    } else {
      allocated_ = new LogMessageData();
      data_ = allocated_;
    }
#else // !defined(GLOG_THREAD_LOCAL_STORAGE)
    allocated_ = new LogMessageData();
    data_ = allocated_;
#endif // defined(GLOG_THREAD_LOCAL_STORAGE)
    data_->first_fatal_ = false;
  } else {
    MutexLock l(&fatal_msg_lock);
    if (fatal_msg_exclusive) {
      fatal_msg_exclusive = false;
      data_ = &fatal_msg_data_exclusive;
      data_->first_fatal_ = true;
    } else {
      data_ = &fatal_msg_data_shared;
      data_->first_fatal_ = false;
    }
  }

  stream().fill('0');
  data_->preserved_errno_ = errno;
  data_->severity_ = severity;
  data_->line_ = line;
  data_->send_method_ = send_method;
  data_->sink_ = NULL;
  data_->outvec_ = NULL;
  WallTime now = WallTime_Now();
  data_->timestamp_ = static_cast<time_t>(now);
  localtime_r(&data_->timestamp_, &data_->tm_time_);
  data_->usecs_ = static_cast<int32>((now - data_->timestamp_) * 1000000);

  data_->num_chars_to_log_ = 0;
  data_->num_chars_to_syslog_ = 0;
  data_->basename_ = const_basename(file);
  data_->fullname_ = file;
  data_->has_been_flushed_ = false;

  // If specified, prepend a prefix to each line.  For example:
  //    I20201018 160715 f5d4fbb0 logging.cc:1153]
  //    (log level, GMT year, month, date, time, thread_id, file basename, line)
  // We exclude the thread_id for the default thread.
  if (FLAGS_log_prefix && (line != kNoLogPrefix)) {
    stream() << LogSeverityNames[severity][0]
             << setw(4) << 1900+data_->tm_time_.tm_year
             << setw(2) << 1+data_->tm_time_.tm_mon
             << setw(2) << data_->tm_time_.tm_mday
             << ' '
             << setw(2) << data_->tm_time_.tm_hour  << ':'
             << setw(2) << data_->tm_time_.tm_min   << ':'
             << setw(2) << data_->tm_time_.tm_sec   << "."
             << setw(6) << data_->usecs_
             << ' '
             << setfill(' ') << setw(5)
             << static_cast<unsigned int>(GetTID()) << setfill('0')
             << ' '
             << data_->basename_ << ':' << data_->line_ << "] ";
  }
  data_->num_prefix_chars_ = data_->stream_.pcount();

  if (!FLAGS_log_backtrace_at.empty()) {
    char fileline[128];
    snprintf(fileline, sizeof(fileline), "%s:%d", data_->basename_, line);
#ifdef HAVE_STACKTRACE
    if (!strcmp(FLAGS_log_backtrace_at.c_str(), fileline)) {
      string stacktrace;
      DumpStackTraceToString(&stacktrace);
      stream() << " (stacktrace:\n" << stacktrace << ") ";
    }
#endif
  }
}

LogMessage::~LogMessage() {
  Flush();
#ifdef GLOG_THREAD_LOCAL_STORAGE
  if (data_ == static_cast<void*>(&thread_msg_data)) {
    data_->~LogMessageData();
    thread_data_available = true;
  }
  else {
    delete allocated_;
  }
#else // !defined(GLOG_THREAD_LOCAL_STORAGE)
  delete allocated_;
#endif // defined(GLOG_THREAD_LOCAL_STORAGE)
}

int LogMessage::preserved_errno() const {
  return data_->preserved_errno_;
}

ostream& LogMessage::stream() {
  return data_->stream_;
}

// Flush buffered message, called by the destructor, or any other function
// that needs to synchronize the log.
void LogMessage::Flush() {
  if (data_->has_been_flushed_ || data_->severity_ < FLAGS_minloglevel)
    return;

  data_->num_chars_to_log_ = data_->stream_.pcount();
  data_->num_chars_to_syslog_ =
    data_->num_chars_to_log_ - data_->num_prefix_chars_;

  // Do we need to add a \n to the end of this message?
  bool append_newline =
      (data_->message_text_[data_->num_chars_to_log_-1] != '\n');
  char original_final_char = '\0';

  // If we do need to add a \n, we'll do it by violating the memory of the
  // ostrstream buffer.  This is quick, and we'll make sure to undo our
  // modification before anything else is done with the ostrstream.  It
  // would be preferable not to do things this way, but it seems to be
  // the best way to deal with this.
  if (append_newline) {
    original_final_char = data_->message_text_[data_->num_chars_to_log_];
    data_->message_text_[data_->num_chars_to_log_++] = '\n';
  }

  // Prevent any subtle race conditions by wrapping a mutex lock around
  // the actual logging action per se.
  {
    MutexLock l(&log_mutex);
    (this->*(data_->send_method_))();
    ++num_messages_[static_cast<int>(data_->severity_)];
  }
  LogDestination::WaitForSinks(data_);

  if (append_newline) {
    // Fix the ostrstream back how it was before we screwed with it.
    // It's 99.44% certain that we don't need to worry about doing this.
    data_->message_text_[data_->num_chars_to_log_-1] = original_final_char;
  }

  // If errno was already set before we enter the logging call, we'll
  // set it back to that value when we return from the logging call.
  // It happens often that we log an error message after a syscall
  // failure, which can potentially set the errno to some other
  // values.  We would like to preserve the original errno.
  if (data_->preserved_errno_ != 0) {
    errno = data_->preserved_errno_;
  }

  // Note that this message is now safely logged.  If we're asked to flush
  // again, as a result of destruction, say, we'll do nothing on future calls.
  data_->has_been_flushed_ = true;
}

// Copy of first FATAL log message so that we can print it out again
// after all the stack traces.  To preserve legacy behavior, we don't
// use fatal_msg_data_exclusive.
static time_t fatal_time;
static char fatal_message[256];

void ReprintFatalMessage() {
  if (fatal_message[0]) {
    const int n = strlen(fatal_message);
    if (!FLAGS_logtostderr) {
      // Also write to stderr (don't color to avoid terminal checks)
      WriteToStderr(fatal_message, n);
    }
    LogDestination::LogToAllLogfiles(GLOG_ERROR, fatal_time, fatal_message, n);
  }
}

// L >= log_mutex (callers must hold the log_mutex).
void LogMessage::SendToLog() EXCLUSIVE_LOCKS_REQUIRED(log_mutex) {
  static bool already_warned_before_initgoogle = false;

  log_mutex.AssertHeld();

  RAW_DCHECK(data_->num_chars_to_log_ > 0 &&
             data_->message_text_[data_->num_chars_to_log_-1] == '\n', "");

  // Messages of a given severity get logged to lower severity logs, too

  if (!already_warned_before_initgoogle && !IsGoogleLoggingInitialized()) {
    const char w[] = "WARNING: Logging before InitGoogleLogging() is "
                     "written to STDERR\n";
    WriteToStderr(w, strlen(w));
    already_warned_before_initgoogle = true;
  }

  // global flag: never log to file if set.  Also -- don't log to a
  // file if we haven't parsed the command line flags to get the
  // program name.
  if (FLAGS_logtostderr || !IsGoogleLoggingInitialized()) {
    ColoredWriteToStderr(data_->severity_,
                         data_->message_text_, data_->num_chars_to_log_);

    // this could be protected by a flag if necessary.
    LogDestination::LogToSinks(data_->severity_,
                               data_->fullname_, data_->basename_,
                               data_->line_, &data_->tm_time_,
                               data_->message_text_ + data_->num_prefix_chars_,
                               (data_->num_chars_to_log_ -
                                data_->num_prefix_chars_ - 1),
                               data_->usecs_);
  } else {

    // log this message to all log files of severity <= severity_
    LogDestination::LogToAllLogfiles(data_->severity_, data_->timestamp_,
                                     data_->message_text_,
                                     data_->num_chars_to_log_);

    LogDestination::MaybeLogToStderr(data_->severity_, data_->message_text_,
                                     data_->num_chars_to_log_);
    LogDestination::MaybeLogToEmail(data_->severity_, data_->message_text_,
                                    data_->num_chars_to_log_);
    LogDestination::LogToSinks(data_->severity_,
                               data_->fullname_, data_->basename_,
                               data_->line_, &data_->tm_time_,
                               data_->message_text_ + data_->num_prefix_chars_,
                               (data_->num_chars_to_log_
                                - data_->num_prefix_chars_ - 1),
                               data_->usecs_);
    // NOTE: -1 removes trailing \n
  }

  // If we log a FATAL message, flush all the log destinations, then toss
  // a signal for others to catch. We leave the logs in a state that
  // someone else can use them (as long as they flush afterwards)
  if (data_->severity_ == GLOG_FATAL && exit_on_dfatal) {
    if (data_->first_fatal_) {
      // Store crash information so that it is accessible from within signal
      // handlers that may be invoked later.
      RecordCrashReason(&crash_reason);
      SetCrashReason(&crash_reason);

      // Store shortened fatal message for other logs and GWQ status
      const int copy = min<int>(data_->num_chars_to_log_,
                                sizeof(fatal_message)-1);
      memcpy(fatal_message, data_->message_text_, copy);
      fatal_message[copy] = '\0';
      fatal_time = data_->timestamp_;
    }

    if (!FLAGS_logtostderr) {
      for (int i = 0; i < NUM_SEVERITIES; ++i) {
        if ( LogDestination::log_destinations_[i] )
          LogDestination::log_destinations_[i]->logger_->Write(true, 0, "", 0);
      }
    }

    // release the lock that our caller (directly or indirectly)
    // LogMessage::~LogMessage() grabbed so that signal handlers
    // can use the logging facility. Alternately, we could add
    // an entire unsafe logging interface to bypass locking
    // for signal handlers but this seems simpler.
    log_mutex.Unlock();
    LogDestination::WaitForSinks(data_);

    const char* message = "*** Check failure stack trace: ***\n";
    if (write(STDERR_FILENO, message, strlen(message)) < 0) {
      // Ignore errors.
    }
    Fail();
  }
}

void LogMessage::RecordCrashReason(
    glog_internal_namespace_::CrashReason* reason) {
  reason->filename = fatal_msg_data_exclusive.fullname_;
  reason->line_number = fatal_msg_data_exclusive.line_;
  reason->message = fatal_msg_data_exclusive.message_text_ +
                    fatal_msg_data_exclusive.num_prefix_chars_;
#ifdef HAVE_STACKTRACE
  // Retrieve the stack trace, omitting the logging frames that got us here.
  reason->depth = GetStackTrace(reason->stack, ARRAYSIZE(reason->stack), 4);
#else
  reason->depth = 0;
#endif
}

#ifdef HAVE___ATTRIBUTE__
# define ATTRIBUTE_NORETURN __attribute__((noreturn))
#else
# define ATTRIBUTE_NORETURN
#endif

#if defined(OS_WINDOWS)
__declspec(noreturn)
#endif
static void logging_fail() ATTRIBUTE_NORETURN;

static void logging_fail() {
  abort();
}

typedef void (*logging_fail_func_t)() ATTRIBUTE_NORETURN;

GOOGLE_GLOG_DLL_DECL
logging_fail_func_t g_logging_fail_func = &logging_fail;

void InstallFailureFunction(void (*fail_func)()) {
  g_logging_fail_func = (logging_fail_func_t)fail_func;
}

void LogMessage::Fail() {
  g_logging_fail_func();
}

// L >= log_mutex (callers must hold the log_mutex).
void LogMessage::SendToSink() EXCLUSIVE_LOCKS_REQUIRED(log_mutex) {
  if (data_->sink_ != NULL) {
    RAW_DCHECK(data_->num_chars_to_log_ > 0 &&
               data_->message_text_[data_->num_chars_to_log_-1] == '\n', "");
    data_->sink_->send(data_->severity_, data_->fullname_, data_->basename_,
                       data_->line_, &data_->tm_time_,
                       data_->message_text_ + data_->num_prefix_chars_,
                       (data_->num_chars_to_log_ -
                        data_->num_prefix_chars_ - 1),
                       data_->usecs_);
  }
}

// L >= log_mutex (callers must hold the log_mutex).
void LogMessage::SendToSinkAndLog() EXCLUSIVE_LOCKS_REQUIRED(log_mutex) {
  SendToSink();
  SendToLog();
}

// L >= log_mutex (callers must hold the log_mutex).
void LogMessage::SaveOrSendToLog() EXCLUSIVE_LOCKS_REQUIRED(log_mutex) {
  if (data_->outvec_ != NULL) {
    RAW_DCHECK(data_->num_chars_to_log_ > 0 &&
               data_->message_text_[data_->num_chars_to_log_-1] == '\n', "");
    // Omit prefix of message and trailing newline when recording in outvec_.
    const char *start = data_->message_text_ + data_->num_prefix_chars_;
    int len = data_->num_chars_to_log_ - data_->num_prefix_chars_ - 1;
    data_->outvec_->push_back(string(start, len));
  } else {
    SendToLog();
  }
}

void LogMessage::WriteToStringAndLog() EXCLUSIVE_LOCKS_REQUIRED(log_mutex) {
  if (data_->message_ != NULL) {
    RAW_DCHECK(data_->num_chars_to_log_ > 0 &&
               data_->message_text_[data_->num_chars_to_log_-1] == '\n', "");
    // Omit prefix of message and trailing newline when writing to message_.
    const char *start = data_->message_text_ + data_->num_prefix_chars_;
    int len = data_->num_chars_to_log_ - data_->num_prefix_chars_ - 1;
    data_->message_->assign(start, len);
  }
  SendToLog();
}

// L >= log_mutex (callers must hold the log_mutex).
void LogMessage::SendToSyslogAndLog() {
#ifdef HAVE_SYSLOG_H
  // Before any calls to syslog(), make a single call to openlog()
  static bool openlog_already_called = false;
  if (!openlog_already_called) {
    openlog(glog_internal_namespace_::ProgramInvocationShortName(),
            LOG_CONS | LOG_NDELAY | LOG_PID,
            LOG_USER);
    openlog_already_called = true;
  }

  // This array maps Google severity levels to syslog levels
  const int SEVERITY_TO_LEVEL[] = { LOG_INFO, LOG_WARNING, LOG_ERR, LOG_EMERG };
  syslog(LOG_USER | SEVERITY_TO_LEVEL[static_cast<int>(data_->severity_)], "%.*s",
         int(data_->num_chars_to_syslog_),
         data_->message_text_ + data_->num_prefix_chars_);
  SendToLog();
#else
  LOG(ERROR) << "No syslog support: message=" << data_->message_text_;
#endif
}

base::Logger* base::GetLogger(LogSeverity severity) {
  MutexLock l(&log_mutex);
  return LogDestination::log_destination(severity)->logger_;
}

void base::SetLogger(LogSeverity severity, base::Logger* logger) {
  MutexLock l(&log_mutex);
  LogDestination::log_destination(severity)->logger_ = logger;
}

// L < log_mutex.  Acquires and releases mutex_.
int64 LogMessage::num_messages(int severity) {
  MutexLock l(&log_mutex);
  return num_messages_[severity];
}

// Output the COUNTER value. This is only valid if ostream is a
// LogStream.
ostream& operator<<(ostream &os, const PRIVATE_Counter&) {
#ifdef DISABLE_RTTI
  LogMessage::LogStream *log = static_cast<LogMessage::LogStream*>(&os);
#else
  LogMessage::LogStream *log = dynamic_cast<LogMessage::LogStream*>(&os);
#endif
  CHECK(log && log == log->self())
      << "You must not use COUNTER with non-glog ostream";
  os << log->ctr();
  return os;
}

ErrnoLogMessage::ErrnoLogMessage(const char* file, int line,
                                 LogSeverity severity, int ctr,
                                 void (LogMessage::*send_method)())
    : LogMessage(file, line, severity, ctr, send_method) {
}

ErrnoLogMessage::~ErrnoLogMessage() {
  // Don't access errno directly because it may have been altered
  // while streaming the message.
  stream() << ": " << StrError(preserved_errno()) << " ["
           << preserved_errno() << "]";
}

void FlushLogFiles(LogSeverity min_severity) {
  LogDestination::FlushLogFiles(min_severity);
}

void FlushLogFilesUnsafe(LogSeverity min_severity) {
  LogDestination::FlushLogFilesUnsafe(min_severity);
}

void SetLogDestination(LogSeverity severity, const char* base_filename) {
  LogDestination::SetLogDestination(severity, base_filename);
}

void SetLogSymlink(LogSeverity severity, const char* symlink_basename) {
  LogDestination::SetLogSymlink(severity, symlink_basename);
}

LogSink::~LogSink() {
}

void LogSink::WaitTillSent() {
  // noop default
}

string LogSink::ToString(LogSeverity severity, const char* file, int line,
                         const struct ::tm* tm_time,
                         const char* message, size_t message_len, int32 usecs) {
  ostringstream stream(string(message, message_len));
  stream.fill('0');

  stream << LogSeverityNames[severity][0]
         << setw(4) << 1900+tm_time->tm_year
         << setw(2) << 1+tm_time->tm_mon
         << setw(2) << tm_time->tm_mday
         << ' '
         << setw(2) << tm_time->tm_hour << ':'
         << setw(2) << tm_time->tm_min << ':'
         << setw(2) << tm_time->tm_sec << '.'
         << setw(6) << usecs
         << ' '
         << setfill(' ') << setw(5) << GetTID() << setfill('0')
         << ' '
         << file << ':' << line << "] ";

  stream << string(message, message_len);
  return stream.str();
}

void AddLogSink(LogSink *destination) {
  LogDestination::AddLogSink(destination);
}

void RemoveLogSink(LogSink *destination) {
  LogDestination::RemoveLogSink(destination);
}

void SetLogFilenameExtension(const char* ext) {
  LogDestination::SetLogFilenameExtension(ext);
}

void SetStderrLogging(LogSeverity min_severity) {
  LogDestination::SetStderrLogging(min_severity);
}

void SetEmailLogging(LogSeverity min_severity, const char* addresses) {
  LogDestination::SetEmailLogging(min_severity, addresses);
}

void LogToStderr() {
  LogDestination::LogToStderr();
}

namespace base {
namespace internal {

bool GetExitOnDFatal();
bool GetExitOnDFatal() {
  MutexLock l(&log_mutex);
  return exit_on_dfatal;
}

// Determines whether we exit the program for a LOG(DFATAL) message in
// debug mode.  It does this by skipping the call to Fail/FailQuietly.
// This is intended for testing only.
//
// This can have some effects on LOG(FATAL) as well.  Failure messages
// are always allocated (rather than sharing a buffer), the crash
// reason is not recorded, the "gwq" status message is not updated,
// and the stack trace is not recorded.  The LOG(FATAL) *will* still
// exit the program.  Since this function is used only in testing,
// these differences are acceptable.
void SetExitOnDFatal(bool value);
void SetExitOnDFatal(bool value) {
  MutexLock l(&log_mutex);
  exit_on_dfatal = value;
}

}  // namespace internal
}  // namespace base

// Shell-escaping as we need to shell out ot /bin/mail.
static const char kDontNeedShellEscapeChars[] =
            "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
            "abcdefghijklmnopqrstuvwxyz"
            "0123456789+-_.=/:,@";

static string ShellEscape(const string& src) {
  string result;
  if (!src.empty() &&  // empty string needs quotes
      src.find_first_not_of(kDontNeedShellEscapeChars) == string::npos) {
    // only contains chars that don't need quotes; it's fine
    result.assign(src);
  } else if (src.find_first_of('\'') == string::npos) {
    // no single quotes; just wrap it in single quotes
    result.assign("'");
    result.append(src);
    result.append("'");
  } else {
    // needs double quote escaping
    result.assign("\"");
    for (size_t i = 0; i < src.size(); ++i) {
      switch (src[i]) {
        case '\\':
        case '$':
        case '"':
        case '`':
          result.append("\\");
      }
      result.append(src, i, 1);
    }
    result.append("\"");
  }
  return result;
}


// use_logging controls whether the logging functions LOG/VLOG are used
// to log errors.  It should be set to false when the caller holds the
// log_mutex.
static bool SendEmailInternal(const char*dest, const char *subject,
                              const char*body, bool use_logging) {
  if (dest && *dest) {
    if ( use_logging ) {
      VLOG(1) << "Trying to send TITLE:" << subject
              << " BODY:" << body << " to " << dest;
    } else {
      fprintf(stderr, "Trying to send TITLE: %s BODY: %s to %s\n",
              subject, body, dest);
    }

    string cmd =
        FLAGS_logmailer + " -s" +
        ShellEscape(subject) + " " + ShellEscape(dest);
    VLOG(4) << "Mailing command: " << cmd;

    FILE* pipe = popen(cmd.c_str(), "w");
    if (pipe != NULL) {
      // Add the body if we have one
      if (body)
        fwrite(body, sizeof(char), strlen(body), pipe);
      bool ok = pclose(pipe) != -1;
      if ( !ok ) {
        if ( use_logging ) {
          LOG(ERROR) << "Problems sending mail to " << dest << ": "
                     << StrError(errno);
        } else {
          fprintf(stderr, "Problems sending mail to %s: %s\n",
                  dest, StrError(errno).c_str());
        }
      }
      return ok;
    } else {
      if ( use_logging ) {
        LOG(ERROR) << "Unable to send mail to " << dest;
      } else {
        fprintf(stderr, "Unable to send mail to %s\n", dest);
      }
    }
  }
  return false;
}

bool SendEmail(const char*dest, const char *subject, const char*body){
  return SendEmailInternal(dest, subject, body, true);
}

static void GetTempDirectories(vector<string>* list) {
  list->clear();
#ifdef OS_WINDOWS
  // On windows we'll try to find a directory in this order:
  //   C:/Documents & Settings/whomever/TEMP (or whatever GetTempPath() is)
  //   C:/TMP/
  //   C:/TEMP/
  //   C:/WINDOWS/ or C:/WINNT/
  //   .
  char tmp[MAX_PATH];
  if (GetTempPathA(MAX_PATH, tmp))
    list->push_back(tmp);
  list->push_back("C:\\tmp\\");
  list->push_back("C:\\temp\\");
#else
  // Directories, in order of preference. If we find a dir that
  // exists, we stop adding other less-preferred dirs
  const char * candidates[] = {
    // Non-null only during unittest/regtest
    getenv("TEST_TMPDIR"),

    // Explicitly-supplied temp dirs
    getenv("TMPDIR"), getenv("TMP"),

    // If all else fails
    "/tmp",
  };

  for (size_t i = 0; i < ARRAYSIZE(candidates); i++) {
    const char *d = candidates[i];
    if (!d) continue;  // Empty env var

    // Make sure we don't surprise anyone who's expecting a '/'
    string dstr = d;
    if (dstr[dstr.size() - 1] != '/') {
      dstr += "/";
    }
    list->push_back(dstr);

    struct stat statbuf;
    if (!stat(d, &statbuf) && S_ISDIR(statbuf.st_mode)) {
      // We found a dir that exists - we're done.
      return;
    }
  }

#endif
}

static vector<string>* logging_directories_list;

const vector<string>& GetLoggingDirectories() {
  // Not strictly thread-safe but we're called early in InitGoogle().
  if (logging_directories_list == NULL) {
    logging_directories_list = new vector<string>;

    if ( !FLAGS_log_dir.empty() ) {
      // A dir was specified, we should use it
      logging_directories_list->push_back(FLAGS_log_dir.c_str());
    } else {
      GetTempDirectories(logging_directories_list);
#ifdef OS_WINDOWS
      char tmp[MAX_PATH];
      if (GetWindowsDirectoryA(tmp, MAX_PATH))
        logging_directories_list->push_back(tmp);
      logging_directories_list->push_back(".\\");
#else
      logging_directories_list->push_back("./");
#endif
    }
  }
  return *logging_directories_list;
}

void TestOnly_ClearLoggingDirectoriesList() {
  fprintf(stderr, "TestOnly_ClearLoggingDirectoriesList should only be "
          "called from test code.\n");
  delete logging_directories_list;
  logging_directories_list = NULL;
}

void GetExistingTempDirectories(vector<string>* list) {
  GetTempDirectories(list);
  vector<string>::iterator i_dir = list->begin();
  while( i_dir != list->end() ) {
    // zero arg to access means test for existence; no constant
    // defined on windows
    if ( access(i_dir->c_str(), 0) ) {
      i_dir = list->erase(i_dir);
    } else {
      ++i_dir;
    }
  }
}

void TruncateLogFile(const char *path, int64 limit, int64 keep) {
#ifdef HAVE_UNISTD_H
  struct stat statbuf;
  const int kCopyBlockSize = 8 << 10;
  char copybuf[kCopyBlockSize];
  int64 read_offset, write_offset;
  // Don't follow symlinks unless they're our own fd symlinks in /proc
  int flags = O_RDWR;
  // TODO(hamaji): Support other environments.
#ifdef OS_LINUX
  const char *procfd_prefix = "/proc/self/fd/";
  if (strncmp(procfd_prefix, path, strlen(procfd_prefix))) flags |= O_NOFOLLOW;
#endif

  int fd = open(path, flags);
  if (fd == -1) {
    if (errno == EFBIG) {
      // The log file in question has got too big for us to open. The
      // real fix for this would be to compile logging.cc (or probably
      // all of base/...) with -D_FILE_OFFSET_BITS=64 but that's
      // rather scary.
      // Instead just truncate the file to something we can manage
      if (truncate(path, 0) == -1) {
        PLOG(ERROR) << "Unable to truncate " << path;
      } else {
        LOG(ERROR) << "Truncated " << path << " due to EFBIG error";
      }
    } else {
      PLOG(ERROR) << "Unable to open " << path;
    }
    return;
  }

  if (fstat(fd, &statbuf) == -1) {
    PLOG(ERROR) << "Unable to fstat()";
    goto out_close_fd;
  }

  // See if the path refers to a regular file bigger than the
  // specified limit
  if (!S_ISREG(statbuf.st_mode)) goto out_close_fd;
  if (statbuf.st_size <= limit)  goto out_close_fd;
  if (statbuf.st_size <= keep) goto out_close_fd;

  // This log file is too large - we need to truncate it
  LOG(INFO) << "Truncating " << path << " to " << keep << " bytes";

  // Copy the last "keep" bytes of the file to the beginning of the file
  read_offset = statbuf.st_size - keep;
  write_offset = 0;
  int bytesin, bytesout;
  while ((bytesin = pread(fd, copybuf, sizeof(copybuf), read_offset)) > 0) {
    bytesout = pwrite(fd, copybuf, bytesin, write_offset);
    if (bytesout == -1) {
      PLOG(ERROR) << "Unable to write to " << path;
      break;
    } else if (bytesout != bytesin) {
      LOG(ERROR) << "Expected to write " << bytesin << ", wrote " << bytesout;
    }
    read_offset += bytesin;
    write_offset += bytesout;
  }
  if (bytesin == -1) PLOG(ERROR) << "Unable to read from " << path;

  // Truncate the remainder of the file. If someone else writes to the
  // end of the file after our last read() above, we lose their latest
  // data. Too bad ...
  if (ftruncate(fd, write_offset) == -1) {
    PLOG(ERROR) << "Unable to truncate " << path;
  }

 out_close_fd:
  close(fd);
#else
  LOG(ERROR) << "No log truncation support.";
#endif
}

void TruncateStdoutStderr() {
#ifdef HAVE_UNISTD_H
  int64 limit = MaxLogSize() << 20;
  int64 keep = 1 << 20;
  TruncateLogFile("/proc/self/fd/1", limit, keep);
  TruncateLogFile("/proc/self/fd/2", limit, keep);
#else
  LOG(ERROR) << "No log truncation support.";
#endif
}


// Helper functions for string comparisons.
#define DEFINE_CHECK_STROP_IMPL(name, func, expected)                   \
  string* Check##func##expected##Impl(const char* s1, const char* s2,   \
                                      const char* names) {              \
    bool equal = s1 == s2 || (s1 && s2 && !func(s1, s2));               \
    if (equal == expected) return NULL;                                 \
    else {                                                              \
      ostringstream ss;                                                 \
      if (!s1) s1 = "";                                                 \
      if (!s2) s2 = "";                                                 \
      ss << #name " failed: " << names << " (" << s1 << " vs. " << s2 << ")"; \
      return new string(ss.str());                                      \
    }                                                                   \
  }
DEFINE_CHECK_STROP_IMPL(CHECK_STREQ, strcmp, true)
DEFINE_CHECK_STROP_IMPL(CHECK_STRNE, strcmp, false)
DEFINE_CHECK_STROP_IMPL(CHECK_STRCASEEQ, strcasecmp, true)
DEFINE_CHECK_STROP_IMPL(CHECK_STRCASENE, strcasecmp, false)
#undef DEFINE_CHECK_STROP_IMPL

int posix_strerror_r(int err, char *buf, size_t len) {
  // Sanity check input parameters
  if (buf == NULL || len <= 0) {
    errno = EINVAL;
    return -1;
  }

  // Reset buf and errno, and try calling whatever version of strerror_r()
  // is implemented by glibc
  buf[0] = '\000';
  int old_errno = errno;
  errno = 0;
  char *rc = reinterpret_cast<char *>(strerror_r(err, buf, len));

  // Both versions set errno on failure
  if (errno) {
    // Should already be there, but better safe than sorry
    buf[0]     = '\000';
    return -1;
  }
  errno = old_errno;

  // POSIX is vague about whether the string will be terminated, although
  // is indirectly implies that typically ERANGE will be returned, instead
  // of truncating the string. This is different from the GNU implementation.
  // We play it safe by always terminating the string explicitly.
  buf[len-1] = '\000';

  // If the function succeeded, we can use its exit code to determine the
  // semantics implemented by glibc
  if (!rc) {
    return 0;
  } else {
    // GNU semantics detected
    if (rc == buf) {
      return 0;
    } else {
      buf[0] = '\000';
#if defined(OS_MACOSX) || defined(OS_FREEBSD) || defined(OS_OPENBSD)
      if (reinterpret_cast<intptr_t>(rc) < sys_nerr) {
        // This means an error on MacOSX or FreeBSD.
        return -1;
      }
#endif
      strncat(buf, rc, len-1);
      return 0;
    }
  }
}

string StrError(int err) {
  char buf[100];
  int rc = posix_strerror_r(err, buf, sizeof(buf));
  if ((rc < 0) || (buf[0] == '\000')) {
    snprintf(buf, sizeof(buf), "Error number %d", err);
  }
  return buf;
}

LogMessageFatal::LogMessageFatal(const char* file, int line) :
    LogMessage(file, line, GLOG_FATAL) {}

LogMessageFatal::LogMessageFatal(const char* file, int line,
                                 const CheckOpString& result) :
    LogMessage(file, line, result) {}

LogMessageFatal::~LogMessageFatal() {
    Flush();
    LogMessage::Fail();
}

namespace base {

CheckOpMessageBuilder::CheckOpMessageBuilder(const char *exprtext)
    : stream_(new ostringstream) {
  *stream_ << exprtext << " (";
}

CheckOpMessageBuilder::~CheckOpMessageBuilder() {
  delete stream_;
}

ostream* CheckOpMessageBuilder::ForVar2() {
  *stream_ << " vs. ";
  return stream_;
}

string* CheckOpMessageBuilder::NewString() {
  *stream_ << ")";
  return new string(stream_->str());
}

}  // namespace base

template <>
void MakeCheckOpValueString(std::ostream* os, const char& v) {
  if (v >= 32 && v <= 126) {
    (*os) << "'" << v << "'";
  } else {
    (*os) << "char value " << (short)v;
  }
}

template <>
void MakeCheckOpValueString(std::ostream* os, const signed char& v) {
  if (v >= 32 && v <= 126) {
    (*os) << "'" << v << "'";
  } else {
    (*os) << "signed char value " << (short)v;
  }
}

template <>
void MakeCheckOpValueString(std::ostream* os, const unsigned char& v) {
  if (v >= 32 && v <= 126) {
    (*os) << "'" << v << "'";
  } else {
    (*os) << "unsigned char value " << (unsigned short)v;
  }
}

void InitGoogleLogging(const char* argv0) {
  glog_internal_namespace_::InitGoogleLoggingUtilities(argv0);
}

void ShutdownGoogleLogging() {
  glog_internal_namespace_::ShutdownGoogleLoggingUtilities();
  LogDestination::DeleteLogDestinations();
  delete logging_directories_list;
  logging_directories_list = NULL;
}

void EnableLogCleaner(int overdue_days) {
  log_cleaner_enabled_ = true;

  // Setting overdue_days to 0 day should not be allowed!
  // Since all logs will be deleted immediately, which will cause troubles.
  if (overdue_days > 0) {
    log_cleaner_overdue_days_ = overdue_days;
  }
}

void DisableLogCleaner() {
  log_cleaner_enabled_ = false;
}

_END_GOOGLE_NAMESPACE_