1 /*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "LogKlog.h"
18
19 #include <ctype.h>
20 #include <errno.h>
21 #include <inttypes.h>
22 #include <limits.h>
23 #include <stdarg.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <sys/prctl.h>
27 #include <sys/uio.h>
28 #include <syslog.h>
29
30 #include <private/android_filesystem_config.h>
31 #include <private/android_logger.h>
32
33 #include "LogBuffer.h"
34
35 #define KMSG_PRIORITY(PRI) \
36 '<', '0' + (LOG_SYSLOG | (PRI)) / 10, '0' + (LOG_SYSLOG | (PRI)) % 10, '>'
37
38 static const char priority_message[] = { KMSG_PRIORITY(LOG_INFO), '\0' };
39
40 // List of the _only_ needles we supply here to android::strnstr
41 static const char suspendStr[] = "PM: suspend entry ";
42 static const char resumeStr[] = "PM: suspend exit ";
43 static const char suspendedStr[] = "Suspended for ";
44 static const char healthdStr[] = "healthd";
45 static const char batteryStr[] = ": battery ";
46 static const char auditStr[] = " audit(";
47 static const char klogdStr[] = "logd.klogd: ";
48
49 // Parsing is hard
50
51 // called if we see a '<', s is the next character, returns pointer after '>'
is_prio(char * s,ssize_t len)52 static char* is_prio(char* s, ssize_t len) {
53 if ((len <= 0) || !isdigit(*s++)) return nullptr;
54 --len;
55 static const size_t max_prio_len = (len < 4) ? len : 4;
56 size_t priolen = 0;
57 char c;
58 while (((c = *s++)) && (++priolen <= max_prio_len)) {
59 if (!isdigit(c)) return ((c == '>') && (*s == '[')) ? s : nullptr;
60 }
61 return nullptr;
62 }
63
64 // called if we see a '[', s is the next character, returns pointer after ']'
is_timestamp(char * s,ssize_t len)65 static char* is_timestamp(char* s, ssize_t len) {
66 while ((len > 0) && (*s == ' ')) {
67 ++s;
68 --len;
69 }
70 if ((len <= 0) || !isdigit(*s++)) return nullptr;
71 --len;
72 bool first_period = true;
73 char c;
74 while ((len > 0) && ((c = *s++))) {
75 --len;
76 if ((c == '.') && first_period) {
77 first_period = false;
78 } else if (!isdigit(c)) {
79 return ((c == ']') && !first_period && (*s == ' ')) ? s : nullptr;
80 }
81 }
82 return nullptr;
83 }
84
85 // Like strtok_r with "\r\n" except that we look for log signatures (regex)
86 // \(\(<[0-9]\{1,4\}>\)\([[] *[0-9]+[.][0-9]+[]] \)\{0,1\}\|[[]
87 // *[0-9]+[.][0-9]+[]] \)
88 // and split if we see a second one without a newline.
89 // We allow nuls in content, monitoring the overall length and sub-length of
90 // the discovered tokens.
91
92 #define SIGNATURE_MASK 0xF0
93 // <digit> following ('0' to '9' masked with ~SIGNATURE_MASK) added to signature
94 #define LESS_THAN_SIG SIGNATURE_MASK
95 #define OPEN_BRACKET_SIG ((SIGNATURE_MASK << 1) & SIGNATURE_MASK)
96 // space is one more than <digit> of 9
97 #define OPEN_BRACKET_SPACE ((char)(OPEN_BRACKET_SIG | 10))
98
log_strntok_r(char * s,ssize_t & len,char * & last,ssize_t & sublen)99 char* android::log_strntok_r(char* s, ssize_t& len, char*& last,
100 ssize_t& sublen) {
101 sublen = 0;
102 if (len <= 0) return nullptr;
103 if (!s) {
104 if (!(s = last)) return nullptr;
105 // fixup for log signature split <,
106 // LESS_THAN_SIG + <digit>
107 if ((*s & SIGNATURE_MASK) == LESS_THAN_SIG) {
108 *s = (*s & ~SIGNATURE_MASK) + '0';
109 *--s = '<';
110 ++len;
111 }
112 // fixup for log signature split [,
113 // OPEN_BRACKET_SPACE is space, OPEN_BRACKET_SIG + <digit>
114 if ((*s & SIGNATURE_MASK) == OPEN_BRACKET_SIG) {
115 *s = (*s == OPEN_BRACKET_SPACE) ? ' ' : (*s & ~SIGNATURE_MASK) + '0';
116 *--s = '[';
117 ++len;
118 }
119 }
120
121 while ((len > 0) && ((*s == '\r') || (*s == '\n'))) {
122 ++s;
123 --len;
124 }
125
126 if (len <= 0) return last = nullptr;
127 char *peek, *tok = s;
128
129 for (;;) {
130 if (len <= 0) {
131 last = nullptr;
132 return tok;
133 }
134 char c = *s++;
135 --len;
136 ssize_t adjust;
137 switch (c) {
138 case '\r':
139 case '\n':
140 s[-1] = '\0';
141 last = s;
142 return tok;
143
144 case '<':
145 peek = is_prio(s, len);
146 if (!peek) break;
147 if (s != (tok + 1)) { // not first?
148 s[-1] = '\0';
149 *s &= ~SIGNATURE_MASK;
150 *s |= LESS_THAN_SIG; // signature for '<'
151 last = s;
152 return tok;
153 }
154 adjust = peek - s;
155 if (adjust > len) {
156 adjust = len;
157 }
158 sublen += adjust;
159 len -= adjust;
160 s = peek;
161 if ((*s == '[') && ((peek = is_timestamp(s + 1, len - 1)))) {
162 adjust = peek - s;
163 if (adjust > len) {
164 adjust = len;
165 }
166 sublen += adjust;
167 len -= adjust;
168 s = peek;
169 }
170 break;
171
172 case '[':
173 peek = is_timestamp(s, len);
174 if (!peek) break;
175 if (s != (tok + 1)) { // not first?
176 s[-1] = '\0';
177 if (*s == ' ') {
178 *s = OPEN_BRACKET_SPACE;
179 } else {
180 *s &= ~SIGNATURE_MASK;
181 *s |= OPEN_BRACKET_SIG; // signature for '['
182 }
183 last = s;
184 return tok;
185 }
186 adjust = peek - s;
187 if (adjust > len) {
188 adjust = len;
189 }
190 sublen += adjust;
191 len -= adjust;
192 s = peek;
193 break;
194 }
195 ++sublen;
196 }
197 // NOTREACHED
198 }
199
200 log_time LogKlog::correction = (log_time(CLOCK_REALTIME) < log_time(CLOCK_MONOTONIC))
201 ? log_time(log_time::EPOCH)
202 : (log_time(CLOCK_REALTIME) - log_time(CLOCK_MONOTONIC));
203
LogKlog(LogBuffer * buf,int fdWrite,int fdRead,bool auditd,LogStatistics * stats)204 LogKlog::LogKlog(LogBuffer* buf, int fdWrite, int fdRead, bool auditd, LogStatistics* stats)
205 : SocketListener(fdRead, false),
206 logbuf(buf),
207 signature(CLOCK_MONOTONIC),
208 initialized(false),
209 enableLogging(true),
210 auditd(auditd),
211 stats_(stats) {
212 static const char klogd_message[] = "%s%s%" PRIu64 "\n";
213 char buffer[strlen(priority_message) + strlen(klogdStr) +
214 strlen(klogd_message) + 20];
215 snprintf(buffer, sizeof(buffer), klogd_message, priority_message, klogdStr,
216 signature.nsec());
217 write(fdWrite, buffer, strlen(buffer));
218 }
219
onDataAvailable(SocketClient * cli)220 bool LogKlog::onDataAvailable(SocketClient* cli) {
221 if (!initialized) {
222 prctl(PR_SET_NAME, "logd.klogd");
223 initialized = true;
224 enableLogging = false;
225 }
226
227 char buffer[LOGGER_ENTRY_MAX_PAYLOAD];
228 ssize_t len = 0;
229
230 for (;;) {
231 ssize_t retval = 0;
232 if (len < (ssize_t)(sizeof(buffer) - 1)) {
233 retval =
234 read(cli->getSocket(), buffer + len, sizeof(buffer) - 1 - len);
235 }
236 if ((retval == 0) && (len <= 0)) {
237 break;
238 }
239 if (retval < 0) {
240 return false;
241 }
242 len += retval;
243 bool full = len == (sizeof(buffer) - 1);
244 char* ep = buffer + len;
245 *ep = '\0';
246 ssize_t sublen;
247 for (char *ptr = nullptr, *tok = buffer;
248 !!(tok = android::log_strntok_r(tok, len, ptr, sublen));
249 tok = nullptr) {
250 if (((tok + sublen) >= ep) && (retval != 0) && full) {
251 if (sublen > 0) memmove(buffer, tok, sublen);
252 len = sublen;
253 break;
254 }
255 if ((sublen > 0) && *tok) {
256 log(tok, sublen);
257 }
258 }
259 }
260
261 return true;
262 }
263
calculateCorrection(const log_time & monotonic,const char * real_string,ssize_t len)264 void LogKlog::calculateCorrection(const log_time& monotonic,
265 const char* real_string, ssize_t len) {
266 static const char real_format[] = "%Y-%m-%d %H:%M:%S.%09q UTC";
267 if (len < (ssize_t)(strlen(real_format) + 5)) return;
268
269 log_time real(log_time::EPOCH);
270 const char* ep = real.strptime(real_string, real_format);
271 if (!ep || (ep > &real_string[len]) || (real > log_time(CLOCK_REALTIME))) {
272 return;
273 }
274 // kernel report UTC, log_time::strptime is localtime from calendar.
275 // Bionic and liblog strptime does not support %z or %Z to pick up
276 // timezone so we are calculating our own correction.
277 time_t now = real.tv_sec;
278 struct tm tm = {.tm_isdst = -1};
279 localtime_r(&now, &tm);
280 if ((tm.tm_gmtoff < 0) && ((-tm.tm_gmtoff) > (long)real.tv_sec)) {
281 real = log_time(log_time::EPOCH);
282 } else {
283 real.tv_sec += tm.tm_gmtoff;
284 }
285 if (monotonic > real) {
286 correction = log_time(log_time::EPOCH);
287 } else {
288 correction = real - monotonic;
289 }
290 }
291
sniffTime(const char * & buf,ssize_t len,bool reverse)292 log_time LogKlog::sniffTime(const char*& buf, ssize_t len, bool reverse) {
293 log_time now(log_time::EPOCH);
294 if (len <= 0) return now;
295
296 const char* cp = nullptr;
297 if ((len > 10) && (*buf == '[')) {
298 cp = now.strptime(buf, "[ %s.%q]"); // can index beyond buffer bounds
299 if (cp && (cp > &buf[len - 1])) cp = nullptr;
300 }
301 if (cp) {
302 len -= cp - buf;
303 if ((len > 0) && isspace(*cp)) {
304 ++cp;
305 --len;
306 }
307 buf = cp;
308
309 const char* b;
310 if (((b = android::strnstr(cp, len, suspendStr))) &&
311 (((b += strlen(suspendStr)) - cp) < len)) {
312 len -= b - cp;
313 calculateCorrection(now, b, len);
314 } else if (((b = android::strnstr(cp, len, resumeStr))) &&
315 (((b += strlen(resumeStr)) - cp) < len)) {
316 len -= b - cp;
317 calculateCorrection(now, b, len);
318 } else if (((b = android::strnstr(cp, len, healthdStr))) &&
319 (((b += strlen(healthdStr)) - cp) < len) &&
320 ((b = android::strnstr(b, len -= b - cp, batteryStr))) &&
321 (((b += strlen(batteryStr)) - cp) < len)) {
322 // NB: healthd is roughly 150us late, so we use it instead to
323 // trigger a check for ntp-induced or hardware clock drift.
324 log_time real(CLOCK_REALTIME);
325 log_time mono(CLOCK_MONOTONIC);
326 correction = (real < mono) ? log_time(log_time::EPOCH) : (real - mono);
327 } else if (((b = android::strnstr(cp, len, suspendedStr))) &&
328 (((b += strlen(suspendStr)) - cp) < len)) {
329 len -= b - cp;
330 log_time real(log_time::EPOCH);
331 char* endp;
332 real.tv_sec = strtol(b, &endp, 10);
333 if ((*endp == '.') && ((endp - b) < len)) {
334 unsigned long multiplier = NS_PER_SEC;
335 real.tv_nsec = 0;
336 len -= endp - b;
337 while (--len && isdigit(*++endp) && (multiplier /= 10)) {
338 real.tv_nsec += (*endp - '0') * multiplier;
339 }
340 if (reverse) {
341 if (real > correction) {
342 correction = log_time(log_time::EPOCH);
343 } else {
344 correction -= real;
345 }
346 } else {
347 correction += real;
348 }
349 }
350 }
351
352 convertMonotonicToReal(now);
353 } else {
354 now = log_time(CLOCK_REALTIME);
355 }
356 return now;
357 }
358
sniffPid(const char * & buf,ssize_t len)359 pid_t LogKlog::sniffPid(const char*& buf, ssize_t len) {
360 if (len <= 0) return 0;
361
362 const char* cp = buf;
363 // sscanf does a strlen, let's check if the string is not nul terminated.
364 // pseudo out-of-bounds access since we always have an extra char on buffer.
365 if (((ssize_t)strnlen(cp, len) == len) && cp[len]) {
366 return 0;
367 }
368 while (len) {
369 // Mediatek kernels with modified printk
370 if (*cp == '[') {
371 int pid = 0;
372 char placeholder;
373 if (sscanf(cp, "[%d:%*[a-z_./0-9:A-Z]]%c", &pid, &placeholder) == 2) {
374 return pid;
375 }
376 break; // Only the first one
377 }
378 ++cp;
379 --len;
380 }
381 if (len > 8 && cp[0] == '[' && cp[7] == ']' && isdigit(cp[6])) {
382 // Linux 5.10 and above, e.g. "[ T1] init: init first stage started!"
383 int i = 5;
384 while (i > 1 && isdigit(cp[i])) {
385 --i;
386 }
387 int pos = i + 1;
388 if (cp[i] != 'T') {
389 return 0;
390 }
391 while (i > 1) {
392 --i;
393 if (cp[i] != ' ') {
394 return 0;
395 }
396 }
397 buf = cp + 8;
398 return atoi(cp + pos);
399 }
400 return 0;
401 }
402
403 // kernel log prefix, convert to a kernel log priority number
parseKernelPrio(const char * & buf,ssize_t len)404 static int parseKernelPrio(const char*& buf, ssize_t len) {
405 int pri = LOG_USER | LOG_INFO;
406 const char* cp = buf;
407 if ((len > 0) && (*cp == '<')) {
408 pri = 0;
409 while (--len && isdigit(*++cp)) {
410 pri = (pri * 10) + *cp - '0';
411 }
412 if ((len > 0) && (*cp == '>')) {
413 ++cp;
414 } else {
415 cp = buf;
416 pri = LOG_USER | LOG_INFO;
417 }
418 buf = cp;
419 }
420 return pri;
421 }
422
423 // Convert kernel log priority number into an Android Logger priority number
convertKernelPrioToAndroidPrio(int pri)424 static int convertKernelPrioToAndroidPrio(int pri) {
425 switch (pri & LOG_PRIMASK) {
426 case LOG_EMERG:
427 case LOG_ALERT:
428 case LOG_CRIT:
429 return ANDROID_LOG_FATAL;
430
431 case LOG_ERR:
432 return ANDROID_LOG_ERROR;
433
434 case LOG_WARNING:
435 return ANDROID_LOG_WARN;
436
437 default:
438 case LOG_NOTICE:
439 case LOG_INFO:
440 break;
441
442 case LOG_DEBUG:
443 return ANDROID_LOG_DEBUG;
444 }
445
446 return ANDROID_LOG_INFO;
447 }
448
strnrchr(const char * s,ssize_t len,char c)449 static const char* strnrchr(const char* s, ssize_t len, char c) {
450 const char* save = nullptr;
451 for (; len > 0; ++s, len--) {
452 if (*s == c) {
453 save = s;
454 }
455 }
456 return save;
457 }
458
459 //
460 // log a message into the kernel log buffer
461 //
462 // Filter rules to parse <PRI> <TIME> <tag> and <message> in order for
463 // them to appear correct in the logcat output:
464 //
465 // LOG_KERN (0):
466 // <PRI>[<TIME>] <tag> ":" <message>
467 // <PRI>[<TIME>] <tag> <tag> ":" <message>
468 // <PRI>[<TIME>] <tag> <tag>_work ":" <message>
469 // <PRI>[<TIME>] <tag> '<tag>.<num>' ":" <message>
470 // <PRI>[<TIME>] <tag> '<tag><num>' ":" <message>
471 // <PRI>[<TIME>] <tag>_host '<tag>.<num>' ":" <message>
472 // (unimplemented) <PRI>[<TIME>] <tag> '<num>.<tag>' ":" <message>
473 // <PRI>[<TIME>] "[INFO]"<tag> : <message>
474 // <PRI>[<TIME>] "------------[ cut here ]------------" (?)
475 // <PRI>[<TIME>] "---[ end trace 3225a3070ca3e4ac ]---" (?)
476 // LOG_USER, LOG_MAIL, LOG_DAEMON, LOG_AUTH, LOG_SYSLOG, LOG_LPR, LOG_NEWS
477 // LOG_UUCP, LOG_CRON, LOG_AUTHPRIV, LOG_FTP:
478 // <PRI+TAG>[<TIME>] (see sys/syslog.h)
479 // Observe:
480 // Minimum tag length = 3 NB: drops things like r5:c00bbadf, but allow PM:
481 // Maximum tag words = 2
482 // Maximum tag length = 16 NB: we are thinking of how ugly logcat can get.
483 // Not a Tag if there is no message content.
484 // leading additional spaces means no tag, inherit last tag.
485 // Not a Tag if <tag>: is "ERROR:", "WARNING:", "INFO:" or "CPU:"
486 // Drop:
487 // empty messages
488 // messages with ' audit(' in them if auditd is running
489 // logd.klogd:
490 // return -1 if message logd.klogd: <signature>
491 //
log(const char * buf,ssize_t len)492 int LogKlog::log(const char* buf, ssize_t len) {
493 if (auditd && android::strnstr(buf, len, auditStr)) {
494 return 0;
495 }
496
497 const char* p = buf;
498 int pri = parseKernelPrio(p, len);
499
500 log_time now = sniffTime(p, len - (p - buf), false);
501
502 // sniff for start marker
503 const char* start = android::strnstr(p, len - (p - buf), klogdStr);
504 if (start) {
505 uint64_t sig = strtoll(start + strlen(klogdStr), nullptr, 10);
506 if (sig == signature.nsec()) {
507 if (initialized) {
508 enableLogging = true;
509 } else {
510 enableLogging = false;
511 }
512 return -1;
513 }
514 return 0;
515 }
516
517 if (!enableLogging) {
518 return 0;
519 }
520
521 // Parse pid, tid and uid
522 const pid_t pid = sniffPid(p, len - (p - buf));
523 const pid_t tid = pid;
524 uid_t uid = AID_ROOT;
525 if (pid) {
526 uid = stats_->PidToUid(pid);
527 }
528
529 // Parse (rules at top) to pull out a tag from the incoming kernel message.
530 // Some may view the following as an ugly heuristic, the desire is to
531 // beautify the kernel logs into an Android Logging format; the goal is
532 // admirable but costly.
533 while ((p < &buf[len]) && (isspace(*p) || !*p)) {
534 ++p;
535 }
536 if (p >= &buf[len]) { // timestamp, no content
537 return 0;
538 }
539 start = p;
540 const char* tag = "";
541 const char* etag = tag;
542 ssize_t taglen = len - (p - buf);
543 const char* bt = p;
544
545 static const char infoBrace[] = "[INFO]";
546 static const ssize_t infoBraceLen = strlen(infoBrace);
547 if ((taglen >= infoBraceLen) &&
548 !fastcmp<strncmp>(p, infoBrace, infoBraceLen)) {
549 // <PRI>[<TIME>] "[INFO]"<tag> ":" message
550 bt = p + infoBraceLen;
551 taglen -= infoBraceLen;
552 }
553
554 const char* et;
555 for (et = bt; (taglen > 0) && *et && (*et != ':') && !isspace(*et);
556 ++et, --taglen) {
557 // skip ':' within [ ... ]
558 if (*et == '[') {
559 while ((taglen > 0) && *et && *et != ']') {
560 ++et;
561 --taglen;
562 }
563 if (taglen <= 0) {
564 break;
565 }
566 }
567 }
568 const char* cp;
569 for (cp = et; (taglen > 0) && isspace(*cp); ++cp, --taglen) {
570 }
571
572 // Validate tag
573 ssize_t size = et - bt;
574 if ((taglen > 0) && (size > 0)) {
575 if (*cp == ':') {
576 // ToDo: handle case insensitive colon separated logging stutter:
577 // <tag> : <tag>: ...
578
579 // One Word
580 tag = bt;
581 etag = et;
582 p = cp + 1;
583 } else if ((taglen > size) && (tolower(*bt) == tolower(*cp))) {
584 // clean up any tag stutter
585 if (!fastcmp<strncasecmp>(bt + 1, cp + 1, size - 1)) { // no match
586 // <PRI>[<TIME>] <tag> <tag> : message
587 // <PRI>[<TIME>] <tag> <tag>: message
588 // <PRI>[<TIME>] <tag> '<tag>.<num>' : message
589 // <PRI>[<TIME>] <tag> '<tag><num>' : message
590 // <PRI>[<TIME>] <tag> '<tag><stuff>' : message
591 const char* b = cp;
592 cp += size;
593 taglen -= size;
594 while ((--taglen > 0) && !isspace(*++cp) && (*cp != ':')) {
595 }
596 const char* e;
597 for (e = cp; (taglen > 0) && isspace(*cp); ++cp, --taglen) {
598 }
599 if ((taglen > 0) && (*cp == ':')) {
600 tag = b;
601 etag = e;
602 p = cp + 1;
603 }
604 } else {
605 // what about <PRI>[<TIME>] <tag>_host '<tag><stuff>' : message
606 static const char host[] = "_host";
607 static const ssize_t hostlen = strlen(host);
608 if ((size > hostlen) &&
609 !fastcmp<strncmp>(bt + size - hostlen, host, hostlen) &&
610 !fastcmp<strncmp>(bt + 1, cp + 1, size - hostlen - 1)) {
611 const char* b = cp;
612 cp += size - hostlen;
613 taglen -= size - hostlen;
614 if (*cp == '.') {
615 while ((--taglen > 0) && !isspace(*++cp) &&
616 (*cp != ':')) {
617 }
618 const char* e;
619 for (e = cp; (taglen > 0) && isspace(*cp);
620 ++cp, --taglen) {
621 }
622 if ((taglen > 0) && (*cp == ':')) {
623 tag = b;
624 etag = e;
625 p = cp + 1;
626 }
627 }
628 } else {
629 goto twoWord;
630 }
631 }
632 } else {
633 // <PRI>[<TIME>] <tag> <stuff>' : message
634 twoWord:
635 while ((--taglen > 0) && !isspace(*++cp) && (*cp != ':')) {
636 }
637 const char* e;
638 for (e = cp; (taglen > 0) && isspace(*cp); ++cp, --taglen) {
639 }
640 // Two words
641 if ((taglen > 0) && (*cp == ':')) {
642 tag = bt;
643 etag = e;
644 p = cp + 1;
645 }
646 }
647 } // else no tag
648
649 static const char cpu[] = "CPU";
650 static const ssize_t cpuLen = strlen(cpu);
651 static const char warning[] = "WARNING";
652 static const ssize_t warningLen = strlen(warning);
653 static const char error[] = "ERROR";
654 static const ssize_t errorLen = strlen(error);
655 static const char info[] = "INFO";
656 static const ssize_t infoLen = strlen(info);
657
658 size = etag - tag;
659 if ((size <= 1) ||
660 // register names like x9
661 ((size == 2) && (isdigit(tag[0]) || isdigit(tag[1]))) ||
662 // register names like x18 but not driver names like en0
663 ((size == 3) && (isdigit(tag[1]) && isdigit(tag[2]))) ||
664 // ignore
665 ((size == cpuLen) && !fastcmp<strncmp>(tag, cpu, cpuLen)) ||
666 ((size == warningLen) && !fastcmp<strncasecmp>(tag, warning, warningLen)) ||
667 ((size == errorLen) && !fastcmp<strncasecmp>(tag, error, errorLen)) ||
668 ((size == infoLen) && !fastcmp<strncasecmp>(tag, info, infoLen))) {
669 p = start;
670 etag = tag = "";
671 }
672
673 // Suppress additional stutter in tag:
674 // eg: [143:healthd]healthd -> [143:healthd]
675 taglen = etag - tag;
676 // Mediatek-special printk induced stutter
677 const char* mp = strnrchr(tag, taglen, ']');
678 if (mp && (++mp < etag)) {
679 ssize_t s = etag - mp;
680 if (((s + s) < taglen) && !fastcmp<memcmp>(mp, mp - 1 - s, s)) {
681 taglen = mp - tag;
682 }
683 }
684 // Deal with sloppy and simplistic harmless p = cp + 1 etc above.
685 if (len < (p - buf)) {
686 p = &buf[len];
687 }
688 // skip leading space
689 while ((p < &buf[len]) && (isspace(*p) || !*p)) {
690 ++p;
691 }
692 // truncate trailing space or nuls
693 ssize_t b = len - (p - buf);
694 while ((b > 0) && (isspace(p[b - 1]) || !p[b - 1])) {
695 --b;
696 }
697 // trick ... allow tag with empty content to be logged. log() drops empty
698 if ((b <= 0) && (taglen > 0)) {
699 p = " ";
700 b = 1;
701 }
702 // This shouldn't happen, but clamp the size if it does.
703 if (b > LOGGER_ENTRY_MAX_PAYLOAD) {
704 b = LOGGER_ENTRY_MAX_PAYLOAD;
705 }
706 if (taglen > LOGGER_ENTRY_MAX_PAYLOAD) {
707 taglen = LOGGER_ENTRY_MAX_PAYLOAD;
708 }
709 // calculate buffer copy requirements
710 ssize_t n = 1 + taglen + 1 + b + 1;
711 // Extra checks for likely impossible cases.
712 if ((taglen > n) || (b > n) || (n > (ssize_t)USHRT_MAX) || (n <= 0)) {
713 return -EINVAL;
714 }
715
716 // Careful.
717 // We are using the stack to house the log buffer for speed reasons.
718 // If we malloc'd this buffer, we could get away without n's USHRT_MAX
719 // test above, but we would then required a max(n, USHRT_MAX) as
720 // truncating length argument to logbuf->log() below. Gain is protection
721 // against stack corruption and speedup, loss is truncated long-line content.
722 char newstr[n];
723 char* np = newstr;
724
725 // Convert priority into single-byte Android logger priority
726 *np = convertKernelPrioToAndroidPrio(pri);
727 ++np;
728
729 // Copy parsed tag following priority
730 memcpy(np, tag, taglen);
731 np += taglen;
732 *np = '\0';
733 ++np;
734
735 // Copy main message to the remainder
736 memcpy(np, p, b);
737 np[b] = '\0';
738
739 {
740 // Watch out for singular race conditions with timezone causing near
741 // integer quarter-hour jumps in the time and compensate accordingly.
742 // Entries will be temporal within near_seconds * 2. b/21868540
743 static uint32_t vote_time[3];
744 vote_time[2] = vote_time[1];
745 vote_time[1] = vote_time[0];
746 vote_time[0] = now.tv_sec;
747
748 if (vote_time[1] && vote_time[2]) {
749 static const unsigned near_seconds = 10;
750 static const unsigned timezones_seconds = 900;
751 int diff0 = (vote_time[0] - vote_time[1]) / near_seconds;
752 unsigned abs0 = (diff0 < 0) ? -diff0 : diff0;
753 int diff1 = (vote_time[1] - vote_time[2]) / near_seconds;
754 unsigned abs1 = (diff1 < 0) ? -diff1 : diff1;
755 if ((abs1 <= 1) && // last two were in agreement on timezone
756 ((abs0 + 1) % (timezones_seconds / near_seconds)) <= 2) {
757 abs0 = (abs0 + 1) / (timezones_seconds / near_seconds) *
758 timezones_seconds;
759 now.tv_sec -= (diff0 < 0) ? -abs0 : abs0;
760 }
761 }
762 }
763
764 // Log message
765 int rc = logbuf->Log(LOG_ID_KERNEL, now, uid, pid, tid, newstr, (uint16_t)n);
766
767 return rc;
768 }
769