android_system_core/logd
Tom Cherry b3e163399a logd: move leading_dropped logic into FlushTo()
This logic isn't generic, so it should not be in the generic
LogReaderThread.

Moreover, it's currently broken in essentially every case except when
filtering by UID, because it runs as in the filter functions before
the actual filtering by pid/etc takes place.  For example, when
filtering by pid, it's possible to get leading chatty messages.  The
newly added test was failing previously but is fixed by this change.

It's fundamentally broken in the tail case.  Take this example:
1: Normal message
2: Chatty message
3: Normal message
4: Normal message

If you read that log buffer with a tail value of 3, there are three
possible outcomes:
1) Messages #2-4, however this would include a leading chatty message,
   which is not allowed.
2) Messages #3-4, however this is only 2, not 3 messages.
3) Messages #1-4, however this is 4, more than the 3 requested
   messages.

This code chooses 2) as the correct solution, in this case, we don't
need to account for leading chatty messages when counting the total
logs in the buffer.  A test is added for this case as well.

Test: new unit test
Change-Id: Id02eb81a8e77390aba4f85aac659c6cab498dbcd
2020-06-02 13:26:48 -07:00
..
fuzz logd: make LogBuffer an interface 2020-05-12 15:39:19 -07:00
.clang-format
Android.bp logd: create SimpleLogBuffer and implement ChattyLogBuffer in terms of it 2020-05-21 14:23:45 -07:00
AndroidTest.xml logd: add LogBufferTest.cpp 2020-05-18 15:51:08 -07:00
ChattyLogBuffer.cpp logd: format LogBufferElement and LogStatistics correctly 2020-06-02 11:38:44 -07:00
ChattyLogBuffer.h logd: create SimpleLogBuffer and implement ChattyLogBuffer in terms of it 2020-05-21 14:23:45 -07:00
ChattyLogBufferTest.cpp logd: move leading_dropped logic into FlushTo() 2020-06-02 13:26:48 -07:00
CommandListener.cpp logd: remove class LogCommand, rename LogCommand.cpp to LogPermissions.cpp 2020-05-15 11:58:47 -07:00
CommandListener.h logd: remove class LogCommand, rename LogCommand.cpp to LogPermissions.cpp 2020-05-15 11:58:47 -07:00
LogAudit.cpp logd: make LogBuffer an interface 2020-05-12 15:39:19 -07:00
LogAudit.h logd: refactor LastLogTimes a bit 2020-05-12 15:39:11 -07:00
LogBuffer.h logd: move leading_dropped logic into FlushTo() 2020-06-02 13:26:48 -07:00
LogBufferElement.cpp logd: format LogBufferElement and LogStatistics correctly 2020-06-02 11:38:44 -07:00
LogBufferElement.h logd: format LogBufferElement and LogStatistics correctly 2020-06-02 11:38:44 -07:00
LogBufferTest.cpp logd: move leading_dropped logic into FlushTo() 2020-06-02 13:26:48 -07:00
LogBufferTest.h logd: drop can_read_security_logs 2020-06-01 14:45:02 -07:00
LogKlog.cpp logd: make LogBuffer an interface 2020-05-12 15:39:19 -07:00
LogKlog.h logd: remove SocketClient from LogBuffer and LogBufferElement 2020-05-14 19:53:45 -07:00
LogListener.cpp logd: remove class LogCommand, rename LogCommand.cpp to LogPermissions.cpp 2020-05-15 11:58:47 -07:00
LogListener.h logd: remove SocketClient from LogBuffer and LogBufferElement 2020-05-14 19:53:45 -07:00
LogPermissions.cpp logd: remove class LogCommand, rename LogCommand.cpp to LogPermissions.cpp 2020-05-15 11:58:47 -07:00
LogPermissions.h logd: remove class LogCommand, rename LogCommand.cpp to LogPermissions.cpp 2020-05-15 11:58:47 -07:00
LogReader.cpp logd: move leading_dropped logic into FlushTo() 2020-06-02 13:26:48 -07:00
LogReader.h logd: remove SocketClient from LogBuffer and LogBufferElement 2020-05-14 19:53:45 -07:00
LogReaderList.cpp logd: create FlushToState class 2020-06-01 14:45:02 -07:00
LogReaderList.h logd: create FlushToState class 2020-06-01 14:45:02 -07:00
LogReaderThread.cpp logd: move leading_dropped logic into FlushTo() 2020-06-02 13:26:48 -07:00
LogReaderThread.h logd: move leading_dropped logic into FlushTo() 2020-06-02 13:26:48 -07:00
LogStatistics.cpp logd: format LogBufferElement and LogStatistics correctly 2020-06-02 11:38:44 -07:00
LogStatistics.h logd: format LogBufferElement and LogStatistics correctly 2020-06-02 11:38:44 -07:00
LogTags.cpp logd: build liblogd and its test on host 2020-05-18 15:54:06 -07:00
LogTags.h logd: create SimpleLogBuffer and implement ChattyLogBuffer in terms of it 2020-05-21 14:23:45 -07:00
LogUtils.h logd: build liblogd and its test on host 2020-05-18 15:54:06 -07:00
LogWhiteBlackList.cpp logd: don't use libcutils properties 2020-05-15 10:26:09 -07:00
LogWhiteBlackList.h logd: format LogBufferElement and LogStatistics correctly 2020-06-02 11:38:44 -07:00
LogWriter.h logd: drop can_read_security_logs 2020-06-01 14:45:02 -07:00
OWNERS
README.auditd
README.property Remove the monotonic option for logging 2020-05-06 13:37:33 -07:00
SimpleLogBuffer.cpp logd: move leading_dropped logic into FlushTo() 2020-06-02 13:26:48 -07:00
SimpleLogBuffer.h logd: move leading_dropped logic into FlushTo() 2020-06-02 13:26:48 -07:00
auditctl.cpp
event.logtags
libaudit.cpp logd: make liblogd just the core logd functionality 2020-05-18 13:03:48 -07:00
libaudit.h logd: make liblogd just the core logd functionality 2020-05-18 13:03:48 -07:00
logd.rc
logd_test.cpp logd: add LogBufferTest.cpp 2020-05-18 15:51:08 -07:00
logtagd.rc Relax permissions on /data/misc/logd 2020-01-21 18:39:19 -08:00
main.cpp logd: create SimpleLogBuffer and implement ChattyLogBuffer in terms of it 2020-05-21 14:23:45 -07:00
rwlock.h logd: use RAII locks and thread annotations 2020-05-21 11:07:04 -07:00

README.property

The properties that logd and friends react to are:

name                       type default  description
ro.logd.auditd             bool   true   Enable selinux audit daemon
ro.logd.auditd.dmesg       bool   true   selinux audit messages sent to dmesg.
ro.logd.auditd.main        bool   true   selinux audit messages sent to main.
ro.logd.auditd.events      bool   true   selinux audit messages sent to events.
persist.logd.security      bool   false  Enable security buffer.
ro.organization_owned      bool   false  Override persist.logd.security to false
ro.logd.kernel             bool+ svelte+ Enable klogd daemon
ro.logd.statistics         bool+ svelte+ Enable logcat -S statistics.
ro.debuggable              number        if not "1", logd.statistics &
                                         ro.logd.kernel default false.
logd.logpersistd.enable    bool   auto   Safe to start logpersist daemon service
logd.logpersistd          string persist Enable logpersist daemon, "logcatd"
                                         turns on logcat -f in logd context.
					 Responds to logcatd, clear and stop.
logd.logpersistd.buffer          persist logpersistd buffers to collect
logd.logpersistd.size            persist logpersistd size in MB
logd.logpersistd.rotate_kbytes   	 persist logpersistd outout file size in KB.
persist.logd.logpersistd   string        Enable logpersist daemon, "logcatd"
                                         turns on logcat -f in logd context.
persist.logd.logpersistd.buffer    all   logpersistd buffers to collect
persist.logd.logpersistd.size      256   logpersistd size in MB
persist.logd.logpersistd.count     256   sets max number of rotated logs to <count>.
persist.logd.logpersistd.rotate_kbytes   1024  logpersistd output file size in KB
persist.logd.size          number  ro    Global default size of the buffer for
                                         all log ids at initial startup, at
                                         runtime use: logcat -b all -G <value>
ro.logd.size               number svelte default for persist.logd.size. Larger
                                         platform default sizes than 256KB are
                                         known to not scale well under log spam
                                         pressure. Address the spam first,
                                         resist increasing the log buffer.
persist.logd.size.<buffer> number  ro    Size of the buffer for <buffer> log
ro.logd.size.<buffer>      number svelte default for persist.logd.size.<buffer>
ro.config.low_ram          bool   false  if true, logd.statistics,
                                         ro.logd.kernel default false,
                                         logd.size 64K instead of 256K.
persist.logd.filter        string        Pruning filter to optimize content.
                                         At runtime use: logcat -P "<string>"
ro.logd.filter       string "~! ~1000/!" default for persist.logd.filter.
                                         This default means to prune the
                                         oldest entries of chattiest UID, and
                                         the chattiest PID of system
                                         (1000, or AID_SYSTEM).
log.tag                   string persist The global logging level, VERBOSE,
                                         DEBUG, INFO, WARN, ERROR, ASSERT or
                                         SILENT. Only the first character is
                                         the key character.
persist.log.tag            string build  default for log.tag
log.tag.<tag>             string persist The <tag> specific logging level.
persist.log.tag.<tag>      string build  default for log.tag.<tag>

NB:
- auto - managed by /init
- bool+ - "true", "false" and comma separated list of "eng" (forced false if
  ro.debuggable is not "1") or "svelte" (forced false if ro.config.low_ram is
  true).
- svelte - see ro.config.low_ram for details.
- svelte+ - see ro.config.low_ram and ro.debuggable for details.
- ro - <base property> temporary override, ro.<base property> platform default.
- persist - <base property> override, persist.<base property> platform default.
- build - VERBOSE for native, DEBUG for jvm isLoggable, or developer option.
- number - support multipliers (K or M) for convenience. Range is limited
  to between 64K and 256M for log buffer sizes. Individual log buffer ids
  such as main, system, ... override global default.
- Pruning filter is of form of a space-separated list of [~][UID][/PID]
  references, where '~' prefix means to blacklist otherwise whitelist. For
  blacklisting, UID or PID may be a '!' to instead reference the chattiest
  client, with the restriction that the PID must be in the UID group 1000
  (system or AID_SYSTEM).