承接各类网站建设,网站seo心态,台州网站优化,营商环境建设局网站logd守护进程1、adb logcat命令2、logd守护进程启动2.1 logd文件目录2.2 main方法启动3、LogBuffer缓存大小3.1 缓存大小优先级设置3.2 缓存大小相关代码位置android12-release1、adb logcat命令
命令功能adb bugreport bugreport.txtbugreport 日志adb shell dmesg …
logd守护进程1、adb logcat命令2、logd守护进程启动2.1 logd文件目录2.2 main方法启动3、LogBuffer缓存大小3.1 缓存大小优先级设置3.2 缓存大小相关代码位置android12-release1、adb logcat命令
命令功能adb bugreport bugreport.txtbugreport 日志adb shell dmesg dmesg.txtdmesg 日志adb logcat -d -v time -b “main” main.txtmain 日志adb logcat -d -v time -b “system” system.txtsystem日志adb logcat -d -v time -b “events” events.txtevents 日志adb logcat -b crash输出crash日志… …等等adb logcat -h查看logcat命令帮助
Usage: logcat [options] [filterspecs]General options:-b, --bufferbuffer Request alternate ring buffer(s):main system radio events crash default allAdditionally, kernel for userdebug and eng builds, andsecurity for Device Owner installations.Multiple -b parameters or comma separated list of buffers areallowed. Buffers are interleaved.Default -b main,system,crash,kernel.-L, --last Dump logs from prior to last reboot from pstore.-c, --clear Clear (flush) the entire log and exit.if -f is specified, clear the specified file and its related rotatedlog files instead.if -L is specified, clear pstore log instead.-d Dump the log and then exit (dont block).--pidpid Only print logs from the given pid.--wrap Sleep for 2 hours or when buffer about to wrap whichevercomes first. Improves efficiency of polling by providingan about-to-wrap wakeup.Formatting:-v, --formatformat Sets log print format verb and adverbs, where format is one of:brief help long process raw tag thread threadtime timeModifying adverbs can be added:color descriptive epoch monotonic printable uid usec UTC year zoneMultiple -v parameters or comma separated list of format and formatmodifiers are allowed.-D, --dividers Print dividers between each log buffer.-B, --binary Output the log in binary.Outfile files:-f, --filefile Log to file instead of stdout.-r, --rotate-kbytesn Rotate log every n kbytes. Requires -f option.-n, --rotate-countcount Sets max number of rotated logs to count, default 4.--idid If the signature id for logging to file changes, then clear theassociated files and continue.Logd control:These options send a control message to the logd daemon on device, print its return message ifapplicable, then exit. They are incompatible with -L, as these attributes do not apply to pstore.-g, --buffer-size Get the size of the ring buffers within logd.-G, --buffer-sizesize Set size of a ring buffer in logd. May suffix with K or M.This can individually control each buffers size with -b.-S, --statistics Output statistics.--pid can be used to provide pid specific stats.-p, --prune Print prune rules. Each rule is specified as UID, UID/PID or /PID. A~ prefix indicates that elements matching the rule should be prunedwith higher priority otherwise theyre pruned with lower priority. Allother pruning activity is oldest first. Special case ~! represents anautomatic pruning for the noisiest UID as determined by the currentstatistics. Special case ~1000/! represents pruning of the worst PIDwithin AID_SYSTEM when AID_SYSTEM is the noisiest UID.-P, --prunelist ... Set prune rules, using same format as listed above. Must be quoted.Filtering:-s Set default filter to silent. Equivalent to filterspec *:S-e, --regexexpr Only print lines where the log message matches expr where expr isan ECMAScript regular expression.-m, --max-countcount Quit after printing count lines. This is meant to be paired with--regex, but will work on its own.--print This option is only applicable when --regex is set and only useful if--max-count is also provided.With --print, logcat will print all messages even if they do notmatch the regex. Logcat will quit after printing the max-count numberof lines that match the regex.-t count Print only the most recent count lines (implies -d).-t time Print the lines since specified time (implies -d).-T count Print only the most recent count lines (does not imply -d).-T time Print the lines since specified time (not imply -d).count is pure numerical, time is MM-DD hh:mm:ss.mmm...YYYY-MM-DD hh:mm:ss.mmm... or sssss.mmm... format.--uiduids Only display log messages from UIDs present in the comma separate listuids. No name look-up is performed, so UIDs must be provided asnumeric values. This option is only useful for the root, log, andsystem users since only those users can view logs from other users.filterspecs are a series oftag[:priority]where tag is a log component tag (or * for all) and priority is:V Verbose (default for tag)D Debug (default for *)I InfoW WarnE ErrorF FatalS Silent (suppress all output)* by itself means *:D and tag by itself means tag:V.
If no * filterspec or -s on command line, all filter defaults to *:V.
eg: *:S tag prints only tag, tag:S suppresses all tag log messages.If not specified on the command line, filterspec is set from ANDROID_LOG_TAGS.If not specified with -v on command line, format is set from ANDROID_PRINTF_LOG
or defaults to threadtime-v format, --formatformat options:Sets log print format verb and adverbs, where format is:brief long process raw tag thread threadtime timeand individually flagged modifying adverbs can be added:color descriptive epoch monotonic printable uid usec UTC year zoneSingle format verbs:brief — Display priority/tag and PID of the process issuing the message.long — Display all metadata fields, separate messages with blank lines.process — Display PID only.raw — Display the raw log message, with no other metadata fields.tag — Display the priority/tag only.thread — Display priority, PID and TID of process issuing the message.threadtime — Display the date, invocation time, priority, tag, and the PIDand TID of the thread issuing the message. (the default format).time — Display the date, invocation time, priority/tag, and PID of theprocess issuing the message.Adverb modifiers can be used in combination:color — Display in highlighted color to match priority. i.e. VERBOSEDEBUG INFO WARNING ERROR FATALdescriptive — events logs only, descriptions from event-log-tags database.epoch — Display time as seconds since Jan 1 1970.monotonic — Display time as cpu seconds since last boot.printable — Ensure that any binary logging content is escaped.uid — If permitted, display the UID or Android ID of logged process.usec — Display time down the microsecond precision.UTC — Display time as UTC.year — Add the year to the displayed time.zone — Add the local timezone to the displayed time.zone — Print using this public named timezone (experimental).2、logd守护进程启动
2.1 logd文件目录
Android系统启动 查看 init 进程解析 rc 文件其中解析 logd.rc调用到logd/main.cpp主函数。 相关目录 system/logging/logd/logd.rc system/logging/logd/main.cpp logd.rc文件
service logd /system/bin/logdsocket logd stream 0666 logd logdsocket logdr seqpacket 0666 logd logdsocket logdw dgrampasscred 0222 logd logdfile /proc/kmsg rfile /dev/kmsg wuser logdgroup logd system package_info readproccapabilities SYSLOG AUDIT_CONTROLpriority 10writepid /dev/cpuset/system-background/tasksservice logd-reinit /system/bin/logd --reinitoneshotdisableduser logdgroup logdwritepid /dev/cpuset/system-background/tasks# Limit SELinux denial generation to 5/second
service logd-auditctl /system/bin/auditctl -r 5oneshotdisableduser logdgroup logdcapabilities AUDIT_CONTROLon fswrite /dev/event-log-tags # content owned by logd
chown logd logd /dev/event-log-tagschmod 0644 /dev/event-log-tagson property:sys.boot_completed1start logd-auditctl
2.2 main方法启动 使用 android::base::KernelLogger 调试logd内部的日志输出这部分日志输出到kernel log中通过dmesg获取/dev/kmsg 处理“reinit”命令 ro.logd.kernel 属性控制获取/proc/kmsg的FD log_buffer 有chatty、serialized、simple模式默认serialized通过属性logd.buffer_type获取LogBuffer 是负责保存所有日志条目的对象。 相关监听线程 /dev/socket/logdr LogReader监听/dev/socket/logdw LogListener监听/dev/socket/logd CommandListener监听
int main(int argc, char* argv[]) {// We want EPIPE when a reader disconnects, not to terminate logd.signal(SIGPIPE, SIG_IGN);// logd is written under the assumption that the timezone is UTC.// If TZ is not set, persist.sys.timezone is looked up in some time utility// libc functions, including mktime. It confuses the logd time handling,// so here explicitly set TZ to UTC, which overrides the property.setenv(TZ, UTC, 1);// issue reinit command. KISS argument parsing.if ((argc 1) argv[1] !strcmp(argv[1], --reinit)) {return issueReinit();}android::base::InitLogging(argv, [](android::base::LogId log_id, android::base::LogSeverity severity,const char* tag, const char* file, unsigned int line, const char* message) {if (tag strcmp(tag, logd) ! 0) {auto prefixed_message android::base::StringPrintf(%s: %s, tag, message);android::base::KernelLogger(log_id, severity, logd, file, line,prefixed_message.c_str());} else {android::base::KernelLogger(log_id, severity, logd, file, line, message);}});static const char dev_kmsg[] /dev/kmsg;int fdDmesg android_get_control_file(dev_kmsg);if (fdDmesg 0) {fdDmesg TEMP_FAILURE_RETRY(open(dev_kmsg, O_WRONLY | O_CLOEXEC));}int fdPmesg -1;bool klogd GetBoolPropertyEngSvelteDefault(ro.logd.kernel);if (klogd) {SetProperty(ro.logd.kernel, true);static const char proc_kmsg[] /proc/kmsg;fdPmesg android_get_control_file(proc_kmsg);if (fdPmesg 0) {fdPmesg TEMP_FAILURE_RETRY(open(proc_kmsg, O_RDONLY | O_NDELAY | O_CLOEXEC));}if (fdPmesg 0) PLOG(ERROR) Failed to open proc_kmsg;}bool auditd GetBoolProperty(ro.logd.auditd, true);DropPrivs(klogd, auditd);// A cache of event log tagsLogTags log_tags;// Pruning configuration.PruneList prune_list;std::string buffer_type GetProperty(logd.buffer_type, serialized);// Partial (required for chatty) or full logging statistics.LogStatistics log_statistics(GetBoolPropertyEngSvelteDefault(logd.statistics),buffer_type serialized);// Serves the purpose of managing the last logs times read on a socket connection, and as a// reader lock on a range of log entries.LogReaderList reader_list;// LogBuffer is the object which is responsible for holding all log entries.LogBuffer* log_buffer nullptr;if (buffer_type chatty) {log_buffer new ChattyLogBuffer(reader_list, log_tags, prune_list, log_statistics);} else if (buffer_type serialized) {log_buffer new SerializedLogBuffer(reader_list, log_tags, log_statistics);} else if (buffer_type simple) {log_buffer new SimpleLogBuffer(reader_list, log_tags, log_statistics);} else {LOG(FATAL) buffer_type must be one of chatty, serialized, or simple;}// LogReader listens on /dev/socket/logdr. When a client// connects, log entries in the LogBuffer are written to the client.LogReader* reader new LogReader(log_buffer, reader_list);if (reader-startListener()) {return EXIT_FAILURE;}// LogListener listens on /dev/socket/logdw for client// initiated log messages. New log entries are added to LogBuffer// and LogReader is notified to send updates to connected clients.LogListener* swl new LogListener(log_buffer);if (!swl-StartListener()) {return EXIT_FAILURE;}// Command listener listens on /dev/socket/logd for incoming logd// administrative commands.CommandListener* cl new CommandListener(log_buffer, log_tags, prune_list, log_statistics);if (cl-startListener()) {return EXIT_FAILURE;}// LogAudit listens on NETLINK_AUDIT socket for selinux// initiated log messages. New log entries are added to LogBuffer// and LogReader is notified to send updates to connected clients.LogAudit* al nullptr;if (auditd) {int dmesg_fd GetBoolProperty(ro.logd.auditd.dmesg, true) ? fdDmesg : -1;al new LogAudit(log_buffer, dmesg_fd, log_statistics);}LogKlog* kl nullptr;if (klogd) {kl new LogKlog(log_buffer, fdDmesg, fdPmesg, al ! nullptr, log_statistics);}readDmesg(al, kl);// failure is an option ... messages are in dmesg (required by standard)if (kl kl-startListener()) {delete kl;}if (al al-startListener()) {delete al;}TEMP_FAILURE_RETRY(pause());return EXIT_SUCCESS;
}3、LogBuffer缓存大小
3.1 缓存大小优先级设置
1、persist.logd.size.[buffer_name]; 比如buffer_name为main、system、events、crash; 2、ro.logd.size.[buffer_name] 3、persist.logd.size 开发模式中可以设置大小 4、ro.logd.size 5、kLogBufferMinSize 64 * 1024 默认64k
3.2 缓存大小相关代码位置
system/logging/logd/SerializedLogBuffer.cpp system/logging/logd/SimpleLogBuffer.cpp system/logging/logd/ChattyLogBuffer.cpp system/logging/logd/LogBuffer.h system/logging/logd/LogSize.cpp system/logging/liblog/logger_name.cpp
