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android_system_core/logd/LogKlog.cpp
Mark Salyzyn b6bee33182 liblog: logd: support logd.timestamp = monotonic 
if ro.logd.timestamp or persist.logd.timestamp are set to the value
monotonic then liblog writer, liblog printing and logd all switch to
recording/printing monotonic time rather than realtime. If reinit
detects a change for presist.logd.timestamp, correct the older entry
timestamps in place.

ToDo: A corner case condition where new log entries in monotonic time
      occur before logd reinit detects persist.logd.timestamp, there
      will be a few out-of-order entries, but with accurate
      timestamps. This problem does not happen for ro.logd.timestamp
      as it is set before logd starts.

NB: This offers a nano second time accuracy on all log entries
    that may be more suitable for merging with other system
    activities, such as systrace, that also use monotonic time. This
    feature is for debugging.

Bug: 23668800
Change-Id: Iee6dab7140061b1a6627254921411f61b01aa5c2
2015-11-03 15:15:51 -08:00

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/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <stdarg.h>
#include <stdlib.h>
#include <sys/prctl.h>
#include <sys/uio.h>
#include <syslog.h>
#include <log/logger.h>
#include "LogKlog.h"
#define KMSG_PRIORITY(PRI) \
'<', \
'0' + (LOG_SYSLOG | (PRI)) / 10, \
'0' + (LOG_SYSLOG | (PRI)) % 10, \
'>'
static const char priority_message[] = { KMSG_PRIORITY(LOG_INFO), '\0' };
// Parsing is hard
// called if we see a '<', s is the next character, returns pointer after '>'
static char *is_prio(char *s, size_t len) {
if (!len || !isdigit(*s++)) {
return NULL;
}
--len;
static const size_t max_prio_len = (len < 4) ? len : 4;
size_t priolen = 0;
char c;
while (((c = *s++)) && (++priolen <= max_prio_len)) {
if (!isdigit(c)) {
return ((c == '>') && (*s == '[')) ? s : NULL;
}
}
return NULL;
}
// called if we see a '[', s is the next character, returns pointer after ']'
static char *is_timestamp(char *s, size_t len) {
while (len && (*s == ' ')) {
++s;
--len;
}
if (!len || !isdigit(*s++)) {
return NULL;
}
--len;
bool first_period = true;
char c;
while (len && ((c = *s++))) {
--len;
if ((c == '.') && first_period) {
first_period = false;
} else if (!isdigit(c)) {
return ((c == ']') && !first_period && (*s == ' ')) ? s : NULL;
}
}
return NULL;
}
// Like strtok_r with "\r\n" except that we look for log signatures (regex)
// \(\(<[0-9]\{1,4\}>\)\([[] *[0-9]+[.][0-9]+[]] \)\{0,1\}\|[[] *[0-9]+[.][0-9]+[]] \)
// and split if we see a second one without a newline.
// We allow nuls in content, monitoring the overall length and sub-length of
// the discovered tokens.
#define SIGNATURE_MASK 0xF0
// <digit> following ('0' to '9' masked with ~SIGNATURE_MASK) added to signature
#define LESS_THAN_SIG SIGNATURE_MASK
#define OPEN_BRACKET_SIG ((SIGNATURE_MASK << 1) & SIGNATURE_MASK)
// space is one more than <digit> of 9
#define OPEN_BRACKET_SPACE ((char)(OPEN_BRACKET_SIG | 10))
char *log_strntok_r(char *s, size_t *len, char **last, size_t *sublen) {
*sublen = 0;
if (!*len) {
return NULL;
}
if (!s) {
if (!(s = *last)) {
return NULL;
}
// fixup for log signature split <,
// LESS_THAN_SIG + <digit>
if ((*s & SIGNATURE_MASK) == LESS_THAN_SIG) {
*s = (*s & ~SIGNATURE_MASK) + '0';
*--s = '<';
++*len;
}
// fixup for log signature split [,
// OPEN_BRACKET_SPACE is space, OPEN_BRACKET_SIG + <digit>
if ((*s & SIGNATURE_MASK) == OPEN_BRACKET_SIG) {
if (*s == OPEN_BRACKET_SPACE) {
*s = ' ';
} else {
*s = (*s & ~SIGNATURE_MASK) + '0';
}
*--s = '[';
++*len;
}
}
while (*len && ((*s == '\r') || (*s == '\n'))) {
++s;
--*len;
}
if (!*len) {
*last = NULL;
return NULL;
}
char *peek, *tok = s;
for (;;) {
if (*len == 0) {
*last = NULL;
return tok;
}
char c = *s++;
--*len;
size_t adjust;
switch (c) {
case '\r':
case '\n':
s[-1] = '\0';
*last = s;
return tok;
case '<':
peek = is_prio(s, *len);
if (!peek) {
break;
}
if (s != (tok + 1)) { // not first?
s[-1] = '\0';
*s &= ~SIGNATURE_MASK;
*s |= LESS_THAN_SIG; // signature for '<'
*last = s;
return tok;
}
adjust = peek - s;
if (adjust > *len) {
adjust = *len;
}
*sublen += adjust;
*len -= adjust;
s = peek;
if ((*s == '[') && ((peek = is_timestamp(s + 1, *len - 1)))) {
adjust = peek - s;
if (adjust > *len) {
adjust = *len;
}
*sublen += adjust;
*len -= adjust;
s = peek;
}
break;
case '[':
peek = is_timestamp(s, *len);
if (!peek) {
break;
}
if (s != (tok + 1)) { // not first?
s[-1] = '\0';
if (*s == ' ') {
*s = OPEN_BRACKET_SPACE;
} else {
*s &= ~SIGNATURE_MASK;
*s |= OPEN_BRACKET_SIG; // signature for '['
}
*last = s;
return tok;
}
adjust = peek - s;
if (adjust > *len) {
adjust = *len;
}
*sublen += adjust;
*len -= adjust;
s = peek;
break;
}
++*sublen;
}
// NOTREACHED
}
log_time LogKlog::correction = log_time(CLOCK_REALTIME) - log_time(CLOCK_MONOTONIC);
LogKlog::LogKlog(LogBuffer *buf, LogReader *reader, int fdWrite, int fdRead, bool auditd) :
SocketListener(fdRead, false),
logbuf(buf),
reader(reader),
signature(CLOCK_MONOTONIC),
initialized(false),
enableLogging(true),
auditd(auditd) {
static const char klogd_message[] = "%slogd.klogd: %" PRIu64 "\n";
char buffer[sizeof(priority_message) + sizeof(klogd_message) + 20 - 4];
snprintf(buffer, sizeof(buffer), klogd_message, priority_message,
signature.nsec());
write(fdWrite, buffer, strlen(buffer));
}
bool LogKlog::onDataAvailable(SocketClient *cli) {
if (!initialized) {
prctl(PR_SET_NAME, "logd.klogd");
initialized = true;
enableLogging = false;
}
char buffer[LOGGER_ENTRY_MAX_PAYLOAD];
size_t len = 0;
for(;;) {
ssize_t retval = 0;
if ((sizeof(buffer) - 1 - len) > 0) {
retval = read(cli->getSocket(), buffer + len, sizeof(buffer) - 1 - len);
}
if ((retval == 0) && (len == 0)) {
break;
}
if (retval < 0) {
return false;
}
len += retval;
bool full = len == (sizeof(buffer) - 1);
char *ep = buffer + len;
*ep = '\0';
size_t sublen;
for(char *ptr = NULL, *tok = buffer;
((tok = log_strntok_r(tok, &len, &ptr, &sublen)));
tok = NULL) {
if (((tok + sublen) >= ep) && (retval != 0) && full) {
memmove(buffer, tok, sublen);
len = sublen;
break;
}
if (*tok) {
log(tok, sublen);
}
}
}
return true;
}
void LogKlog::calculateCorrection(const log_time &monotonic,
const char *real_string,
size_t len) {
log_time real;
const char *ep = real.strptime(real_string, "%Y-%m-%d %H:%M:%S.%09q UTC");
if (!ep || (ep > &real_string[len])) {
return;
}
// kernel report UTC, log_time::strptime is localtime from calendar.
// Bionic and liblog strptime does not support %z or %Z to pick up
// timezone so we are calculating our own correction.
time_t now = real.tv_sec;
struct tm tm;
memset(&tm, 0, sizeof(tm));
tm.tm_isdst = -1;
localtime_r(&now, &tm);
real.tv_sec += tm.tm_gmtoff;
correction = real - monotonic;
}
static const char suspendStr[] = "PM: suspend entry ";
static const char resumeStr[] = "PM: suspend exit ";
static const char suspendedStr[] = "Suspended for ";
static const char *strnstr(const char *s, size_t len, const char *needle) {
char c;
if (!len) {
return NULL;
}
if ((c = *needle++) != 0) {
size_t needleLen = strlen(needle);
do {
do {
if (len <= needleLen) {
return NULL;
}
--len;
} while (*s++ != c);
} while (fast<memcmp>(s, needle, needleLen));
s--;
}
return s;
}
void LogKlog::sniffTime(log_time &now,
const char **buf, size_t len,
bool reverse) {
const char *cp = now.strptime(*buf, "[ %s.%q]");
if (cp && (cp >= &(*buf)[len])) {
cp = NULL;
}
len -= cp - *buf;
if (cp) {
static const char healthd[] = "healthd";
static const char battery[] = ": battery ";
if (len && isspace(*cp)) {
++cp;
--len;
}
*buf = cp;
if (isMonotonic()) {
return;
}
const char *b;
if (((b = strnstr(cp, len, suspendStr)))
&& ((size_t)((b += sizeof(suspendStr) - 1) - cp) < len)) {
len -= b - cp;
calculateCorrection(now, b, len);
} else if (((b = strnstr(cp, len, resumeStr)))
&& ((size_t)((b += sizeof(resumeStr) - 1) - cp) < len)) {
len -= b - cp;
calculateCorrection(now, b, len);
} else if (((b = strnstr(cp, len, healthd)))
&& ((size_t)((b += sizeof(healthd) - 1) - cp) < len)
&& ((b = strnstr(b, len -= b - cp, battery)))
&& ((size_t)((b += sizeof(battery) - 1) - cp) < len)) {
len -= b - cp;
// NB: healthd is roughly 150us late, worth the price to deal with
// ntp-induced or hardware clock drift.
// look for " 2???-??-?? ??:??:??.????????? ???"
for (; len && *b && (*b != '\n'); ++b, --len) {
if ((b[0] == ' ') && (b[1] == '2') && (b[5] == '-')) {
calculateCorrection(now, b + 1, len - 1);
break;
}
}
} else if (((b = strnstr(cp, len, suspendedStr)))
&& ((size_t)((b += sizeof(suspendStr) - 1) - cp) < len)) {
len -= b - cp;
log_time real;
char *endp;
real.tv_sec = strtol(b, &endp, 10);
if ((*endp == '.') && ((size_t)(endp - b) < len)) {
unsigned long multiplier = NS_PER_SEC;
real.tv_nsec = 0;
len -= endp - b;
while (--len && isdigit(*++endp) && (multiplier /= 10)) {
real.tv_nsec += (*endp - '0') * multiplier;
}
if (reverse) {
correction -= real;
} else {
correction += real;
}
}
}
convertMonotonicToReal(now);
} else {
if (isMonotonic()) {
now = log_time(CLOCK_MONOTONIC);
} else {
now = log_time(CLOCK_REALTIME);
}
}
}
pid_t LogKlog::sniffPid(const char *cp, size_t len) {
while (len) {
// Mediatek kernels with modified printk
if (*cp == '[') {
int pid = 0;
char dummy;
if (sscanf(cp, "[%d:%*[a-z_./0-9:A-Z]]%c", &pid, &dummy) == 2) {
return pid;
}
break; // Only the first one
}
++cp;
--len;
}
return 0;
}
// kernel log prefix, convert to a kernel log priority number
static int parseKernelPrio(const char **buf, size_t len) {
int pri = LOG_USER | LOG_INFO;
const char *cp = *buf;
if (len && (*cp == '<')) {
pri = 0;
while(--len && isdigit(*++cp)) {
pri = (pri * 10) + *cp - '0';
}
if (len && (*cp == '>')) {
++cp;
} else {
cp = *buf;
pri = LOG_USER | LOG_INFO;
}
*buf = cp;
}
return pri;
}
// Passed the entire SYSLOG_ACTION_READ_ALL buffer and interpret a
// compensated start time.
void LogKlog::synchronize(const char *buf, size_t len) {
const char *cp = strnstr(buf, len, suspendStr);
if (!cp) {
cp = strnstr(buf, len, resumeStr);
if (!cp) {
return;
}
} else {
const char *rp = strnstr(buf, len, resumeStr);
if (rp && (rp < cp)) {
cp = rp;
}
}
do {
--cp;
} while ((cp > buf) && (*cp != '\n'));
if (*cp == '\n') {
++cp;
}
parseKernelPrio(&cp, len - (cp - buf));
log_time now;
sniffTime(now, &cp, len - (cp - buf), true);
const char *suspended = strnstr(buf, len, suspendedStr);
if (!suspended || (suspended > cp)) {
return;
}
cp = suspended;
do {
--cp;
} while ((cp > buf) && (*cp != '\n'));
if (*cp == '\n') {
++cp;
}
parseKernelPrio(&cp, len - (cp - buf));
sniffTime(now, &cp, len - (cp - buf), true);
}
// Convert kernel log priority number into an Android Logger priority number
static int convertKernelPrioToAndroidPrio(int pri) {
switch(pri & LOG_PRIMASK) {
case LOG_EMERG:
// FALLTHRU
case LOG_ALERT:
// FALLTHRU
case LOG_CRIT:
return ANDROID_LOG_FATAL;
case LOG_ERR:
return ANDROID_LOG_ERROR;
case LOG_WARNING:
return ANDROID_LOG_WARN;
default:
// FALLTHRU
case LOG_NOTICE:
// FALLTHRU
case LOG_INFO:
break;
case LOG_DEBUG:
return ANDROID_LOG_DEBUG;
}
return ANDROID_LOG_INFO;
}
static const char *strnrchr(const char *s, size_t len, char c) {
const char *save = NULL;
for (;len; ++s, len--) {
if (*s == c) {
save = s;
}
}
return save;
}
//
// log a message into the kernel log buffer
//
// Filter rules to parse <PRI> <TIME> <tag> and <message> in order for
// them to appear correct in the logcat output:
//
// LOG_KERN (0):
// <PRI>[<TIME>] <tag> ":" <message>
// <PRI>[<TIME>] <tag> <tag> ":" <message>
// <PRI>[<TIME>] <tag> <tag>_work ":" <message>
// <PRI>[<TIME>] <tag> '<tag>.<num>' ":" <message>
// <PRI>[<TIME>] <tag> '<tag><num>' ":" <message>
// <PRI>[<TIME>] <tag>_host '<tag>.<num>' ":" <message>
// (unimplemented) <PRI>[<TIME>] <tag> '<num>.<tag>' ":" <message>
// <PRI>[<TIME>] "[INFO]"<tag> : <message>
// <PRI>[<TIME>] "------------[ cut here ]------------" (?)
// <PRI>[<TIME>] "---[ end trace 3225a3070ca3e4ac ]---" (?)
// LOG_USER, LOG_MAIL, LOG_DAEMON, LOG_AUTH, LOG_SYSLOG, LOG_LPR, LOG_NEWS
// LOG_UUCP, LOG_CRON, LOG_AUTHPRIV, LOG_FTP:
// <PRI+TAG>[<TIME>] (see sys/syslog.h)
// Observe:
// Minimum tag length = 3 NB: drops things like r5:c00bbadf, but allow PM:
// Maximum tag words = 2
// Maximum tag length = 16 NB: we are thinking of how ugly logcat can get.
// Not a Tag if there is no message content.
// leading additional spaces means no tag, inherit last tag.
// Not a Tag if <tag>: is "ERROR:", "WARNING:", "INFO:" or "CPU:"
// Drop:
// empty messages
// messages with ' audit(' in them if auditd is running
// logd.klogd:
// return -1 if message logd.klogd: <signature>
//
int LogKlog::log(const char *buf, size_t len) {
if (auditd && strnstr(buf, len, " audit(")) {
return 0;
}
const char *p = buf;
int pri = parseKernelPrio(&p, len);
log_time now;
sniffTime(now, &p, len - (p - buf), false);
// sniff for start marker
const char klogd_message[] = "logd.klogd: ";
const char *start = strnstr(p, len - (p - buf), klogd_message);
if (start) {
uint64_t sig = strtoll(start + sizeof(klogd_message) - 1, NULL, 10);
if (sig == signature.nsec()) {
if (initialized) {
enableLogging = true;
} else {
enableLogging = false;
}
return -1;
}
return 0;
}
if (!enableLogging) {
return 0;
}
// Parse pid, tid and uid
const pid_t pid = sniffPid(p, len - (p - buf));
const pid_t tid = pid;
const uid_t uid = pid ? logbuf->pidToUid(pid) : 0;
// Parse (rules at top) to pull out a tag from the incoming kernel message.
// Some may view the following as an ugly heuristic, the desire is to
// beautify the kernel logs into an Android Logging format; the goal is
// admirable but costly.
while ((isspace(*p) || !*p) && (p < &buf[len])) {
++p;
}
if (p >= &buf[len]) { // timestamp, no content
return 0;
}
start = p;
const char *tag = "";
const char *etag = tag;
size_t taglen = len - (p - buf);
if (!isspace(*p) && *p) {
const char *bt, *et, *cp;
bt = p;
if (!fast<strncmp>(p, "[INFO]", 6)) {
// <PRI>[<TIME>] "[INFO]"<tag> ":" message
bt = p + 6;
taglen -= 6;
}
for(et = bt; taglen && *et && (*et != ':') && !isspace(*et); ++et, --taglen) {
// skip ':' within [ ... ]
if (*et == '[') {
while (taglen && *et && *et != ']') {
++et;
--taglen;
}
}
}
for(cp = et; taglen && isspace(*cp); ++cp, --taglen);
size_t size;
if (*cp == ':') {
// One Word
tag = bt;
etag = et;
p = cp + 1;
} else if (taglen) {
size = et - bt;
if ((*bt == *cp) && fast<strncmp>(bt + 1, cp + 1, size - 1)) {
// <PRI>[<TIME>] <tag>_host '<tag>.<num>' : message
if (!fast<strncmp>(bt + size - 5, "_host", 5)
&& !fast<strncmp>(bt + 1, cp + 1, size - 6)) {
const char *b = cp;
cp += size - 5;
taglen -= size - 5;
if (*cp == '.') {
while (--taglen && !isspace(*++cp) && (*cp != ':'));
const char *e;
for(e = cp; taglen && isspace(*cp); ++cp, --taglen);
if (*cp == ':') {
tag = b;
etag = e;
p = cp + 1;
}
}
} else {
while (--taglen && !isspace(*++cp) && (*cp != ':'));
const char *e;
for(e = cp; taglen && isspace(*cp); ++cp, --taglen);
// Two words
if (*cp == ':') {
tag = bt;
etag = e;
p = cp + 1;
}
}
} else if (isspace(cp[size])) {
cp += size;
taglen -= size;
while (--taglen && isspace(*++cp));
// <PRI>[<TIME>] <tag> <tag> : message
if (*cp == ':') {
tag = bt;
etag = et;
p = cp + 1;
}
} else if (cp[size] == ':') {
// <PRI>[<TIME>] <tag> <tag> : message
tag = bt;
etag = et;
p = cp + size + 1;
} else if ((cp[size] == '.') || isdigit(cp[size])) {
// <PRI>[<TIME>] <tag> '<tag>.<num>' : message
// <PRI>[<TIME>] <tag> '<tag><num>' : message
const char *b = cp;
cp += size;
taglen -= size;
while (--taglen && !isspace(*++cp) && (*cp != ':'));
const char *e = cp;
while (taglen && isspace(*cp)) {
++cp;
--taglen;
}
if (*cp == ':') {
tag = b;
etag = e;
p = cp + 1;
}
} else {
while (--taglen && !isspace(*++cp) && (*cp != ':'));
const char *e = cp;
while (taglen && isspace(*cp)) {
++cp;
--taglen;
}
// Two words
if (*cp == ':') {
tag = bt;
etag = e;
p = cp + 1;
}
}
}
size = etag - tag;
if ((size <= 1)
// register names like x9
|| ((size == 2) && (isdigit(tag[0]) || isdigit(tag[1])))
// register names like x18 but not driver names like en0
|| ((size == 3) && (isdigit(tag[1]) && isdigit(tag[2])))
// blacklist
|| ((size == 3) && !fast<strncmp>(tag, "CPU", 3))
|| ((size == 7) && !fast<strncasecmp>(tag, "WARNING", 7))
|| ((size == 5) && !fast<strncasecmp>(tag, "ERROR", 5))
|| ((size == 4) && !fast<strncasecmp>(tag, "INFO", 4))) {
p = start;
etag = tag = "";
}
}
// Suppress additional stutter in tag:
// eg: [143:healthd]healthd -> [143:healthd]
taglen = etag - tag;
// Mediatek-special printk induced stutter
const char *mp = strnrchr(tag, ']', taglen);
if (mp && (++mp < etag)) {
size_t s = etag - mp;
if (((s + s) < taglen) && !fast<memcmp>(mp, mp - 1 - s, s)) {
taglen = mp - tag;
}
}
// skip leading space
while ((isspace(*p) || !*p) && (p < &buf[len])) {
++p;
}
// truncate trailing space or nuls
size_t b = len - (p - buf);
while (b && (isspace(p[b-1]) || !p[b-1])) {
--b;
}
// trick ... allow tag with empty content to be logged. log() drops empty
if (!b && taglen) {
p = " ";
b = 1;
}
if (b > LOGGER_ENTRY_MAX_PAYLOAD) {
b = LOGGER_ENTRY_MAX_PAYLOAD;
}
size_t n = 1 + taglen + 1 + b + 1;
int rc = n;
if ((taglen > n) || (b > n)) { // Can not happen ...
rc = -EINVAL;
return rc;
}
char newstr[n];
char *np = newstr;
// Convert priority into single-byte Android logger priority
*np = convertKernelPrioToAndroidPrio(pri);
++np;
// Copy parsed tag following priority
memcpy(np, tag, taglen);
np += taglen;
*np = '\0';
++np;
// Copy main message to the remainder
memcpy(np, p, b);
np[b] = '\0';
// Log message
rc = logbuf->log(LOG_ID_KERNEL, now, uid, pid, tid, newstr,
(n <= USHRT_MAX) ? (unsigned short) n : USHRT_MAX);
// notify readers
if (!rc) {
reader->notifyNewLog();
}
return rc;
}
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