qiushao@qiushao-PC:~$ tail .profile # set PATH so it includes user's private bin if it exists if [ -d "$HOME/.local/bin" ] ; then PATH="$HOME/.local/bin:$PATH" fi
mint@mint-pc:~$ apt search libqt | grep dev | grep -v i386 p libqt5-ukui-style-dev - Development files of libqt5-ukui-style1 p libqt5charts5-dev - Qt charts development files p libqt5datavisualization5-dev - APIs for data visualization functionality - development files p libqt5gamepad5-dev - Qt 5 gamepad module - development files p libqt5gstreamer-dev - Development headers for QtGStreamer - Qt 5 build p libqt5networkauth5-dev - online account access for Qt apps - Development Files v libqt5opengl5-desktop-dev - i A libqt5opengl5-dev - Qt 5 OpenGL library development files p libqt5pas-dev - Development files for Qt5Pas p libqt5remoteobjects5-dev - Qt module for IPC — development files v libqt5scintilla2-dev - p libqt5scxml5-dev - Qt module for creating state machines from SCXML files development p libqt5sensors5-dev - Qt 5 Sensors development files p libqt5serialbus5-dev - Qt serialbus serial bus access development p libqt5serialport5-dev - Qt 5 serial port development files p libqt5svg5-dev - Qt 5 SVG module development files p libqt5texttospeech5-dev - Speech library for Qt - development files p libqt5virtualkeyboard5-dev - Qt virtual keyboard - development files p libqt5waylandclient5-dev - QtWayland client development files p libqt5waylandcompositor5-dev - QtWayland compositor development files p libqt5webchannel5-dev - Web communication library for Qt - development files p libqt5webkit5-dev - Web content engine library for Qt - development files p libqt5websockets5-dev - Qt 5 Web Sockets module - development files
mint@mint-pc:~$ apt search qt5serialport p A libqt5serialport5 - Qt 5 serial port support p libqt5serialport5-dev - Qt 5 serial port development files p qt5serialport-examples - Qt 5 serial port examples
]]>
<p>最近想写些 pc 的小工具给自己使用。决定使用 qt5 来开发，首先需要安装开发包。网上的教程基本都是从 qt 官网上下载安装包安装的，另外一些教程则只是安装了基本开发包而已，没有安装文档和 example 的。<br>因此记录一下使用 apt 安装 qt5 开发包及文档，
Linux Mint 20 安装微信http://qiushao.net/2020/07/28/Linux/linuxmint-install-wechat/2020-07-28T14:00:00.000Z2021-01-04T13:37:15.247Z最近 Linux Mint 20 发布了，手痒又折腾了一下。体验了几天，个人感觉非常好，就是国产那堆应用安装麻烦了一点。感谢 deepin 对很多国产应用做了移植，适配工作，让我们可以直接在 debian 系的系统上直接安装使用。下面以安装微信为例说明一下在 debian 系的系统上怎么安装 deepin 适配过的部分国产应用。
mint@mint-pc:~$ apt search deepin p deepin-calculator - Calculator for DDE (Deepin Desktop Environment) p deepin-deb-installer - Deepin Package Manager i A deepin-fonts-wine - Windows API implementation - fonts v deepin-fonts-wine:i386 - p deepin-gettext-tools - Deepin Internationalization utilities p deepin-icon-theme - Icon Theme for Deepin software and Deepin Desktop Environment p deepin-image-viewer - Image Viewer for Deepin Desktop Environment i A deepin-libwine:i386 - Windows API implementation - library p deepin-menu - Deepin menu service p deepin-movie - Deepin movie player p deepin-music - music player with brilliant and tweakful UI p deepin-notifications - System notifications for Deepin Desktop Environment p deepin-picker - Color picker tool for deepin p deepin-screen-recorder - Simple recorder tools for deepin 视频录制工具 p deepin-screenshot - Advanced screen shoting tool 截图工具 p deepin-shortcut-viewer - Pop-up shortcut viewer for Deepin applications p deepin-terminal - Deepin terminal emulator application p deepin-voice-recorder - Deepin's Voice recorder 录音工具 i A deepin-wine - Windows API implementation - standard suite v deepin-wine:i386 - i A deepin-wine-helper:i386 - Deepin Wine Helper v deepin-wine-plugin - i A deepin-wine-plugin:i386 - Deepin Wine plugin i A deepin-wine-plugin-virtual - Deepin Wine plugin virtual package v deepin-wine-plugin-virtual:i386 - i A deepin-wine-uninstaller:i386 - Deepin Wine Uninstaller Tool v deepin-wine32 - i A deepin-wine32:i386 - Windows API implementation - 32-bit binary loader i A deepin-wine32-preloader:i386 - Windows API implementation - prelinked 32-bit binary loader p deepin.cn.360.yasuo:i386 - 360zip on Deepin Wine p deepin.cn.com.winrar:i386 - WinRAR on Deepin Wine p deepin.com.95579.cjsc:i386 - CHANGJIANG SECURITIES Client on Deepin Wine p deepin.com.aaa-logo:i386 - SWGSoft AAALogo on Deepin Wine p deepin.com.baidu.pan:i386 - Baidu net disk client on Deepin Wine 百度网盘 p deepin.com.cmbchina:i386 - CMBChina Client on Deepin Wine i deepin.com.foxmail:i386 - Tencent Foxmail Client on Deepin Wine p deepin.com.gtja.fuyi:i386 - GUOTAI JUNAN SECURITIES RichEasy Client on Deepin Wine p deepin.com.qq.b.crm:i386 - Tencent bizQQ Client on Deepin Wine p deepin.com.qq.b.eim:i386 - Tencent QQEIM Client on Deepin Wine p deepin.com.qq.im:i386 - Tencent QQ Client on Deepin Wine QQ p deepin.com.qq.im.light:i386 - Tencent QQ Client on Deepin Wine TIM p deepin.com.qq.office:i386 - Tencent TIM Client on Deepin Wine p deepin.com.qq.rtx2015:i386 - Tencent QQ Client on Deepin Wine p deepin.com.taobao.aliclient.qianniu:i386 - Ali Qian Niu Client on Deepin Wine 阿里千牛 p deepin.com.taobao.wangwang:i386 - Ali WangWang Client on Deepin Wine 阿里旺旺 p deepin.com.thunderspeed:i386 - Thunder Speed Client on Deepin Wine 迅雷下载 i deepin.com.wechat:i386 - Tencent WeChat Client on Deepin Wine 微信 p deepin.com.weixin.work:i386 - Tencent WeChat Work Client on Deepin Wine 企业微信 p deepin.net.263.em:i386 - 263 EM Client on Deepin Wine p deepin.org.7-zip:i386 - 7-Zip on Deepin Wine p deepin.org.foobar2000:i386 - Foobar2000 on Deepin Wine v deepinwine-cmbchina:i386 - v libqt5deepintheme-plugin - mint@mint-pc:~$
XDG_DATA_DIRS=${XDG_DATA_DIRS:-/usr/local/share:/usr/share} for deepin_dir in /opt/apps/*/entries; do if [ -d "$deepin_dir/applications" ]; then XDG_DATA_DIRS="$XDG_DATA_DIRS:$deepin_dir" fi done export XDG_DATA_DIRS
qiushao@qiushao-pc:~/projects/opensources/gperftools$ file .libs/libtcmalloc.so* .libs/libtcmalloc.so: symbolic link to libtcmalloc.so.4.5.5 .libs/libtcmalloc.so.4: symbolic link to libtcmalloc.so.4.5.5 .libs/libtcmalloc.so.4.5.5: ELF 32-bit LSB shared object, ARM, EABI5 version 1 (GNU/Linux), dynamically linked, with debug_info, not stripped qiushao@qiushao-pc:~/projects/opensources/gperftools$
2. tcmalloc 使用
我们先在 pc 上测试一下效果，如果能满足我们的需求的话，再到板子上进行测试。 先写个有内存泄漏的 demo：
qiushao@qiushao-pc:~/projects/test$ LD_PRELOAD=/usr/local/lib/libtcmalloc.so HEAPCHECK=normal ./tcmalloc_test WARNING: Perftools heap leak checker is active -- Performance may suffer tcmalloc testdo something with buffer do something with buffer do something with buffer do something with buffer do something with buffer do something with buffer do something with buffer do something with buffer do something with buffer do something with buffer Have memory regions w/o callers: might report false leaks Leak check _main_ detected leaks of 10485760 bytes in 10 objects The 1 largest leaks: *** WARNING: Cannot convert addresses to symbols in output below. *** Reason: Cannot find 'pprof' (is PPROF_PATH set correctly?) *** If you cannot fix this, try running pprof directly. Leak of 10485760 bytes in 10 objects allocated from: @ 55d4280a4732 @ 55d4280a4763 @ 55d4280a47d2 @ 7fc6cb53bb97 @ 55d4280a463a
If the preceding stack traces are not enough to find the leaks, try running THIS shell command:
If you are still puzzled about why the leaks are there, try rerunning this program with HEAP_CHECK_TEST_POINTER_ALIGNMENT=1 and/or with HEAP_CHECK_MAX_POINTER_OFFSET=-1 If the leak report occurs in a small fraction of runs, try running with TCMALLOC_MAX_FREE_QUEUE_SIZE of few hundred MB or with TCMALLOC_RECLAIM_MEMORY=false, it might help find lea Exiting with error code (instead of crashing) because of whole-program memory leaks qiushao@qiushao-pc:~/projects/test$
tcmalloc 的内存泄漏检查生效时会有这个警告：WARNING: Perftools heap leak checker is active -- Performance may suffer 运行完程序之后，提示: Leak of 10485760 bytes in 10 objects allocated from: 。即有 10 处内存地址泄漏了，总共泄漏了 10485760 bytes。 tcmalloc 会在 /tmp 目录下生成一个 heap 文件：/tmp/tcmalloc_test.14180.main-end.heap。这个文件记录了所有的内存分配信息。 pprof 是 gperftools 自带的一个 perl 脚本，如果我们之前有 make install 的话，直接使用就行，没有 make install 的话，就得设置一下环境变量了。 我们可以通过 pprof 脚本来解析 heap 文件，获取每一个内存泄漏的位置及调用堆栈：
qiushao@qiushao-pc:~/projects/test$ pprof ./tcmalloc_test "/tmp/tcmalloc_test.14180._main_-end.heap" --lines --text --stack Using local file ./tcmalloc_test. Using local file /tmp/tcmalloc_test.14180._main_-end.heap. Total: 10 objects Stacks:
~ # LD_PRELOAD=/vendor/lib/libtcmalloc.so HEAPCHECK=normal /vendor/bin/tcmalloc_ test WARNING: Perftools heap leak checker is active -- Performance may suffer tcmalloc testdo something with buffer do something with buffer do something with buffer do something with buffer do something with buffer do something with buffer do something with buffer do something with buffer do something with buffer do something with buffer Have memory regions w/o callers: might report false leaks Leak check _main_ detected leaks of 10485760 bytes in 10 objects The 1 largest leaks: *** WARNING: Cannot convert addresses to symbols in output below. *** Reason: Cannot find 'pprof' (is PPROF_PATH set correctly?) *** If you cannot fix this, try running pprof directly. Leak of 10485760 bytes in 10 objects allocated from:
If the preceding stack traces are not enough to find the leaks, try running THIS shell command:
If you are still puzzled about why the leaks are there, try rerunning this program with HEAP_CHECK_TEST_POINTER_ALIGNMENT=1 and/or with HEAP_CHECK_MAX_POINTER_OFFSET=-1 If the leak report occurs in a small fraction of runs, try running with TCMALLOC_MAX_FREE_QUEUE_SIZE of few hundred MB or with TCMALLOC_RECLAIM_MEMORY=false, it might help Exiting with error code (instead of crashing) because of whole-program memory leaks ~ #
同样也生成了 “/tmp/tcmalloc_test.251.main-end.heap” 文件。由于在板子上没法跑 pprof 脚本。这个脚本实际上是 perl 脚本，还依赖一大堆其他工具。 我们可以把 “/tmp/tcmalloc_test.251.main-end.heap” 文件 copy 到 pc 上，然后在 pc 用 pprof 进行分析。
如何替换标准库的内存分配，释放函数： LD_PRELOAD 是 Linux 系统的一个环境变量，它可以影响程序的运行时的链接，它允许你定义在程序运行前优先加载的动态链接库。这个功能主要就是用来有选择性的载入不同动态链接库中的相同函数。通过这个环境变量，我们可以在主程序和其动态链接库的中间加载别的动态链接库，甚至覆盖正常的函数库。一方面，我们可以以此功能来使用自己的或是更好的函数（无需别人的源码），而另一方面，我们也可以以向别人的程序注入程序，从而达到特定的目的。
如何在程序 main 函数结束后，执行内存泄漏分析： 只要定义一个全局静态类变量就行，这个变量的构造函数会在 main 之前执行，析构函数会在 main 函数之后执行。
func helloHook(ctx android.LoadHookContext) { //AConfig() function is at build/soong/android/config.go fmt.Println("PlatformSdkVersion = ", ctx.AConfig().PlatformSdkVersion()) type props struct { Enabled *bool } p := &props{} var int_platform_sdk_version int int_platform_sdk_version = ctx.AConfig().PlatformSdkVersionInt()
海思提供的媒体处理软件平台(Media Process Platform,简称 MPP),可支持应用软件快速开发。该平台对应用软件屏蔽了芯片相关的复杂的底层处理,并对应用软件直接提供 MPI(MPP Program Interface)接口完成相应功能。该平台支持应用软件快速开发以下功能:输入视频捕获、H.265/H.264/JPEG 编码、H.265/H.264/JPEG 解码、视频输出显示、视频图像前处理(包括去噪、增强、锐化)、图像拼接、图像几何矫正、智能、音频捕获及输出、音频编解码等功能。
2. 系统分层结构
系统大概层次结构如下：
硬件层 硬件层由 Hi35xx 芯片加上必要的外围器件构成。外围器件包括 Flash、DDR、视频 Sensor 或 AD、音频 AD 等。
视频缓存池主要向媒体业务提供大块物理内存管理功能，负责内存的分配和回收，充分发挥内存缓存池的作用，让物理内存资源在各个媒体处理模块中合理使用。一组大小相同、物理地址连续的缓存块组成一个视频缓存池。 视频输入通道需要使用公共视频缓存池。所有的视频输入通道都可以从公共视频缓存池中获取视频缓存块用于保存采集的图像（如图中所示从公共视频缓存池 B 中获取视频缓存块 Bm）。由于视频输入通道不提供创建和销毁公共视频缓存池功能，因此，在系统初始化之前，必须为视频输入通道配置公共视频缓存池。
典型的公共视频缓存池数据流图如下：
VI 从公共视频缓存池 B 中获取视频缓存块 Bm,缓存块 Bm 经 VI发送给 VPSS,输入缓存块 Bm 经过 VPSS 处理之后被释放回公共视频缓存池。假设 VPSS 通道的工作模式是 USER, 则 VPSS 通道 0 从公共视频缓存池 B 中获取缓存块 Bi 作为输出图像缓存 buffer 发送给 VENC,VPSS 通道 1 从公共视频缓存池 B 中获取缓存块 Bk 作为输出图像缓存 buffer 发送给 VO,Bi 经 VENC 编码完之后释放回公共视频缓存池,Bk 经 VO 显示完之后释放回公共视频缓存池。
%p - insert pid into filename 添加pid %u - insert current uid into filename 添加当前uid %g - insert current gid into filename 添加当前gid %s - insert signal that caused the coredump into the filename 添加导致产生core的信号 %t - insert UNIX time that the coredump occurred into filename 添加core文件生成时的unix时间 %h - insert hostname where the coredump happened into filename 添加主机名 %e - insert coredumping executable name into filename 添加命令名
/data # ls core_test_252 test /data # gdb test core_test_252 GNU gdb (GDB) 7.9.1 Copyright (C) 2015 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "arm-himix200-linux". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from test...done. [New LWP 252]
warning: Could not load shared library symbols for linux-vdso.so.1. Do you need "set solib-search-path" or "set sysroot"? Core was generated by `./test'. Program terminated with signal SIGSEGV, Segmentation fault. #0 0x00010530 in get_value (value=0x0) at main.cpp:4 4 main.cpp: No such file or directory. (gdb) bt #0 0x00010530 in get_value (value=0x0) at main.cpp:4 #1 0x00010568 in main (argc=1, argv=0xbeedfe34) at main.cpp:9 (gdb)
经过上面的步骤，我们的系统是跑起来了，但只是把 kernel 启动了，根文件系统挂载了而已，什么业务都没有运行的。我们需要编写自己的应用在上面运行才可以。 在写代码之前我们还需要配置一下板子的网络环境，以便开发调试。在开发阶段,推荐使用 NFS 作为开发环境,可以省去重新制作和烧写根文件系统的工作。也不需要频繁用 u 盘 copy 文件。
4.1 pc端配置nfs服务
pc 端 nfs 服务的配置之前已经介绍过了，这里面就不再重复。我们把 nfs share 的目录改成 Hi3519AV100_SDK：
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qiushao@qiushao-pc:/etc$ cat exports # /etc/exports: the access control list for filesystems which may be exported # to NFS clients. See exports(5). # # Example for NFSv2 and NFSv3: # /srv/homes hostname1(rw,sync,no_subtree_check) hostname2(ro,sync,no_subtree_check) # # Example for NFSv4: # /srv/nfs4 gss/krb5i(rw,sync,fsid=0,crossmnt,no_subtree_check) # /srv/nfs4/homes gss/krb5i(rw,sync,no_subtree_check) # /media/qiushao/source-code/Hi3519AV100_SDK *(rw,sync,no_subtree_check,root_squash) qiushao@qiushao-pc:/etc$ qiushao@qiushao-pc:/etc$ sudo exportfs -a qiushao@qiushao-pc:/etc$ sudo service nfs-kernel-server restart
4.2 设置板子的 mac,ip 等信息
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~ # ifconfig eth0 hw ether 40:74:e0:b3:f2:64 ~ # ifconfig eth0 192.168.3.30 netmask 255.255.255.0 IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready ~ # hi_gmac_v200 40e0000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
~ # route add default gw 192.168.3.1 ~ # ping 192.168.3.29 PING 192.168.3.29 (192.168.3.29): 56 data bytes 64 bytes from 192.168.3.29: seq=0 ttl=64 time=43.142 ms 64 bytes from 192.168.3.29: seq=1 ttl=64 time=62.610 ms 64 bytes from 192.168.3.29: seq=2 ttl=64 time=76.662 ms
qiushao@qiushao-pc:/media/qiushao/source-code/Hi3519AV100_SDK/smp/a53_linux/mpp/sample$ cd vio qiushao@qiushao-pc:/media/qiushao/source-code/Hi3519AV100_SDK/smp/a53_linux/mpp/sample/vio$ ls Makefile res sample_vio.h sample_vio_main.c smp qiushao@qiushao-pc:/media/qiushao/source-code/Hi3519AV100_SDK/smp/a53_linux/mpp/sample/vio$ make ... qiushao@qiushao-pc:/media/qiushao/source-code/Hi3519AV100_SDK/smp/a53_linux/mpp/sample/vio$ ls Makefile res sample_vio.h sample_vio_main sample_vio_main.c sample_vio_main.o smp
qiushao@qiushao-pc:~$ sudo exportfs -a qiushao@qiushao-pc:~$ sudo service nfs-kernel-server restart qiushao@qiushao-pc:~$
这样服务端就配置完成啦。
3. 客户端访问测试
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qiushao@qiushao-pc:~$ sudo mount localhost:/home/qiushao/nfs-share /mnt qiushao@qiushao-pc:~$ cd /mnt qiushao@qiushao-pc:/mnt$ ls qiushao@qiushao-pc:/mnt$ touch foobar qiushao@qiushao-pc:/mnt$ ls ~/nfs-share/ foobar
我们先在 /home/qiushao/tftp-root 目录下创建一个文件 foobar， 然后在 /home/qiushao 目录执行 tftp get 来下载文件:
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qiushao@qiushao-pc:~$ cd tftp-root/ qiushao@qiushao-pc:~/tftp-root$ touch foobar qiushao@qiushao-pc:~/tftp-root$ ls foobar qiushao@qiushao-pc:~/tftp-root$ cd qiushao@qiushao-pc:~$ tftp localhost tftp> get foobar qiushao@qiushao-pc:~$ ls foobar foobar qiushao@qiushao-pc:~$
qiushao@qiushao-pc:~/projects/opensources/TscanCode$ tscancode -h TscanCode - A tool for static C/C++ code analysis
Syntax: tscancode [OPTIONS] [files or paths]
If a directory is given instead of a filename, *.cpp, *.cxx, *.cc, *.c++, *.c, *.tpp, and *.txx files are checked recursively from the given directory.
Options: -D<ID> Define preprocessor symbol. Unless --max-configs or --force is used, TscanCode will only check the given configuration when -D is used. Example: '-DDEBUG=1 -D__cplusplus'. -U<ID> Undefine preprocessor symbol. Use -U to explicitly hide certain #ifdef <ID> code paths from checking. Example: '-UDEBUG' --enable=<id> Enable additional checks. The available ids are: * all Enable all checks. It is recommended to only use --enable=all when the whole program is scanned, because this enables unusedFunction. * warning Enable warning messages * style Enable all coding style checks. All messages with the severities 'style', 'performance' and 'portability' are enabled. * performance Enable performance messages * portability Enable portability messages * information Enable information messages * unusedFunction Check for unused functions. It is recommend to only enable this when the whole program is scanned. * missingInclude Warn if there are missing includes. For detailed information, use '--check-config'. Several ids can be given if you separate them with commas. See also --std -h, --help Print this help. -I <dir> Give path to search for include files. Give several -I parameters to give several paths. First given path is searched for contained header files first. If paths are relative to source files, this is not needed. -j <jobs> Start [jobs] threads to do the checking simultaneously. -q, --quiet Do not show progress reports. --xml Write results in xml format to error stream (stderr).
Example usage: # Recursively check the current folder. Print the progress on the screen and # write errors to a file: tscancode . 2> err.txt
qiushao@qiushao-pc:~/projects/opensources/TscanCode$ tscancode samples 2> result.txt Failed to load setting file 'cfg.xml'. File not found Failed to load library configuration file 'std.cfg'. File not found Failed to load library configuration file 'posix.cfg'. File not found Failed to load library configuration file 'windows.cfg'. File not found
qiushao@qiushao-pc:~/source/android-10/system/core/adb$ cpplint.py --verbose=5 --counting=toplevel adb.cpp adb.cpp:33: <chrono> is an unapproved C++11 header. [build/c++11] [5] adb.cpp:34: <condition_variable> is an unapproved C++11 header. [build/c++11] [5] adb.cpp:35: <mutex> is an unapproved C++11 header. [build/c++11] [5] adb.cpp:37: <thread> is an unapproved C++11 header. [build/c++11] [5] adb.cpp:62: Do not use namespace using-directives. Use using-declarations instead. [build/namespaces] [5] adb.cpp:135: Missing space before ( in switch( [whitespace/parens] [5] adb.cpp:135: Missing space before { [whitespace/braces] [5] adb.cpp:322: Missing space before ( in switch( [whitespace/parens] [5] adb.cpp:322: Missing space before { [whitespace/braces] [5] adb.cpp:390: Missing space before ( in if( [whitespace/parens] [5] Done processing adb.cpp Category 'build' errors found: 5 Category 'whitespace' errors found: 5 Total errors found: 10
#!/bin/sh # # An example hook script to verify what is about to be committed. # Called by "git commit" with no arguments. The hook should #exit with non-zero status after issuing an appropriate message if # it wants to stop the commit. # # To enable this hook, rename this file to "pre-commit".
if git rev-parse --verify HEAD >/dev/null 2>&1 then against=HEAD else # Initial commit: diff against an empty tree object against=4b825dc642cb6eb9a060e54bf8d69288fbee4904 fi
# Redirect output to stderr. exec 1>&2
cpplint=cpplint.py sum=0 filters='-whitespace/line_length,-build/include' #for cpp for file in $(git diff-index --name-status $against -- | grep -E '\.[ch](pp)?$' | awk '{print $2}'); do $cpplint --filter=$filters $file sum=$(expr ${sum} + $?) done if [ ${sum} -eq 0 ]; then exit 0 else exit 1 fi
我们来尝试提交一个有错误的代码：
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qiushao@qiushao-pc:~/projects/clion/test$ git commit -m 'test' main.cpp:0: No copyright message found. You should have a line: "Copyright [year] <Copyright Owner>" [legal/copyright] [5] main.cpp:2: Line contains invalid UTF-8 (or Unicode replacement character). [readability/utf8] [5] main.cpp:7: Could not find a newline character at the end of the file. [whitespace/ending_newline] [5] Done processing main.cpp Total errors found: 3 qiushao@qiushao-pc:~/projects/clion/test$
]]>
<p>上一篇文章我们已经制定了编码规范，但规范条例这么多，是不可能人工 review 的，必须得用工具自动化检查才行。<br>因为我们使用的是 google 的编码规范，所以我们直接使用 google 提供的编码规范检查工具 <a href="https://github.com
c++编码规范http://qiushao.net/2020/03/11/c++/c++%E7%BC%96%E7%A0%81%E8%A7%84%E8%8C%83/2020-03-11T06:00:00.000Z2020-12-27T01:22:23.748Z本文中的规范大部分是参考 google 发布的 c++ 编码规范，有同学翻译成了中文版本。但这个规范我觉得顺序有点乱，有些地方讨论太详细，有些地方又表达得不清楚。因此整理，挑选了部分规范。
1. 文件编码格式
1.1 文件编码：统一使用 utf-8 编码
如果文件编码不统一，又有同学使用中文注释的话，就很容易出现乱码的问题。应该所有的文本编辑器都是支持 utf-8 编码的。Linux 的文本编辑器默认使用的都是 utf-8 编码。但 windows 的系统文本编辑器大部分默认编码是 gbk， 所以使用 windows 的同学需要检测一下自己使用的代码编辑器是否已经设置默认编码为 utf-8 了。
int price_count_reader; // 无缩写 int num_errors; // "num" 是一个常见的写法 int num_dns_connections; // 人人都知道 "DNS" 是什么
不好的命名：
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int n; // 毫无意义. int nerr; // 含糊不清的缩写. int n_comp_conns; // 含糊不清的缩写. int wgc_connections; // 只有贵团队知道是什么意思. int pc_reader; // "pc" 有太多可能的解释了. int cstmr_id; // 删减了若干字母.
// Returns an iterator for this table. It is the client's // responsibility to delete the iterator when it is done with it, // and it must not use the iterator once the GargantuanTable object // on which the iterator was created has been deleted. // // The iterator is initially positioned at the beginning of the table. // // This method is equivalent to: // Iterator* iter = table->NewIterator(); // iter->Seek(""); // return iter; // If you are going to immediately seek to another place in the // returned iterator, it will be faster to use NewIterator() // and avoid the extra seek. Iterator* GetIterator()const;
private: // Used to bounds-check table accesses. -1 means // that we don't yet know how many entries the table has. int num_total_entries_;
全局变量 和数据成员一样, 所有全局变量也要注释说明含义及用途, 以及作为全局变量的原因。 比如:
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// The total number of tests cases that we run through in this regression test. constint kNumTestCases = 6;
7.6 实现注释
总述 对于代码中巧妙的, 晦涩的, 有趣的, 重要的地方加以注释。
说明
代码前注释 巧妙或复杂的代码段前要加注释. 比如:
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// Divide result by two, taking into account that x // contains the carry from the add. for (int i = 0; i < result->size(); i++) { x = (x << 8) + (*result)[i]; (*result)[i] = x >> 1; x &= 1; }
行注释 比较隐晦的地方要在行尾加入注释, 在行尾空两格进行注释. 比如:
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// If we have enough memory, mmap the data portion too. mmap_budget = max<int64>(0, mmap_budget - index_->length()); if (mmap_budget >= data_size_ && !MmapData(mmap_chunk_bytes, mlock)) return; // Error already logged.
不允许的行为 不要描述显而易见的现象, 永远不要 用自然语言翻译代码作为注释, 除非即使对深入理解 C++ 的读者来说代码的行为都是不明显的。 要假设读代码的人 C++ 水平比你高, 即便他/她可能不知道你的用意。 你所提供的注释应当解释代码为什么要这么做和代码的目的, 或者最好是让代码自文档化. 比较这样的注释:
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// Find the element in the vector. <-- 差: 这太明显了! auto iter = std::find(v.begin(), v.end(), element); if (iter != v.end()) { Process(element); }
和这样的注释:
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// Process "element" unless it was already processed. auto iter = std::find(v.begin(), v.end(), element); if (iter != v.end()) { Process(element); }
自文档化的代码根本就不需要注释. 上面例子中的注释对下面的代码来说就是毫无必要的:
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if (!IsAlreadyProcessed(element)) { Process(element); }
7.7 TODO 注释
总述 对那些临时的, 短期的解决方案, 或已经够好但仍不完美的代码使用 TODO 注释。
说明 TODO 注释要使用全大写的字符串 TODO, 在随后的圆括号里写上你的名字, 邮件地址, bug ID, 或其它身份标识和与这一 TODO 相关的 issue。 主要目的是让添加注释的人 (也是可以请求提供更多细节的人) 可根据规范的 TODO 格式进行查找. 添加 TODO 注释并不意味着你要自己来修正, 因此当你加上带有姓名的 TODO 时, 一般都是写上自己的名字。
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// TODO(kl@gmail.com): Use a "*" here for concatenation operator. // TODO(Zeke) change this to use relations. // TODO(bug 12345): remove the "Last visitors" feature
如果加 TODO 是为了在 “将来某一天做某事”, 可以附上一个非常明确的时间 (“Fix by November 2005”), 或者一个明确的事项 (“Remove this code when all clients can handle XML responses.”)。
on init # 创建各种系统运行所需的目录，更改各种目录的权限 mkdir /mnt/media_rw 0750 root media_rw mkdir /mnt/user 0755 root root # Start logd before any other services run to ensure we capture all of their logs. start logd
enter_namespace <type> <path> Enters the namespace of type type located at path. Only network namespaces are supported with type set to “net”. Note that only one namespace of a given type may be entered.
service vendor.drm-hal-1-0 /vendor/bin/hw/android.hardware.drm@1.0-service interface android.hardware.drm@1.0::ICryptoFactory default interface android.hardware.drm@1.0::IDrmFactory default class hal user media group mediadrm drmrpc
Mark that the service can be overridden (via the ‘override’ option) later in the boot sequence by APEXes. When a service with updatable option is started before APEXes are all activated, the execution is delayed until the activation is finished. A service that is not marked as updatable cannot be overridden by APEXes.
user <username> 在启动 Service 前修改进程的所属用户, 默认启动时 user 为 root (安全起见，或许默认应该是 nobody)。 在Android M版本，如果一个进程想拥有 Linux capabilities（相当于Android中的权限吧），也只能通过设置这个值。 以前，一个程序要想有 Linux capabilities，必须先以root身份运行，然后再降级到所需的uid。现在已经有一套新的机制取而代之，它通过 fs_config 允许厂商赋予特殊二进制文件 Linux capabilities。 这套机制的说明文档在 https://source.android.google.cn/devices/tech/config/filesystem.html。 当使用这套新的机制时，程序可以通过 user 参数选择自己所需的 uid, 而不需要以 root 权限运行. 在 Android O 版本，程序可以通过 capabilities option 直接申请所需的能力，参见上面的 capabilities 说明。
This version of init contains code to perform “bootcharting”: generating log files that can be later processed by the tools provided by http://www.bootchart.org/.
On the emulator, use the -bootchart timeout option to boot with bootcharting activated for timeout seconds.
On a device:
adb shell 'touch /data/bootchart/enabled'
Don’t forget to delete this file when you’re done collecting data!
The log files are written to /data/bootchart/. A script is provided to retrieve them and create a bootchart.tgz file that can be used with the bootchart command-line utility:
One thing to watch for is that the bootchart will show init as if it started running at 0s. You’ll have to look at dmesg to work out when the kernel actually started init.
Comparing two bootcharts
A handy script named compare-bootcharts.py can be used to compare the start/end time of selected processes. The aforementioned grab-bootchart.sh will leave a bootchart tarball named bootchart.tgz at /tmp/android-bootchart. If two such barballs are preserved on the host machine under different directories, the script can list the timestamps differences. For example:
process: baseline experiment (delta) - Unit is ms (a jiffy is 10 ms on the system)------------------------------------/init: 50 40 (-10)/system/bin/surfaceflinger: 4320 4470 (+150)/system/bin/bootanimation: 6980 6990 (+10)zygote64: 10410 10640 (+230)zygote: 10410 10640 (+230)system_server: 15350 15150 (-200)bootanimation ends at: 33790 31230 (-2560)
Here is an example of trace events of “wm” and “am” categories:
$ANDROID_BUILD_TOP/external/chromium-trace/systrace.py \ wm am --boot
This command will cause the device to reboot. After the device is rebooted and the boot sequence has finished, the trace report is obtained from the device and written as trace.html on the host by hitting Ctrl+C.
Limitation: recording trace events is started after persistent properties are loaded, so the trace events that are emitted before that are not recorded. Several services such as vold, surfaceflinger, and servicemanager are affected by this limitation since they are started before persistent properties are loaded. Zygote initialization and the processes that are forked from the zygote are not affected.
Debugging init
Launching init services without init is not recommended as init sets up a significant amount of environment (user, groups, security label, capabilities, etc) that is hard to replicate manually.
If it is required to debug a service from its very start, the sigstop service option is added. This option will send SIGSTOP to a service immediately before calling exec. This gives a window where developers can attach a debugger, strace, etc before continuing the service with SIGCONT.
This flag can also be dynamically controled via the ctl.sigstop_on and ctl.sigstop_off properties.
Below is an example of dynamically debugging logd via the above:
stop logdsetprop ctl.sigstop_on logdstart logdps -e | grep logd> logd 4343 1 18156 1684 do_signal_stop 538280 T initgdbclient.py -p 4343b mainccc> Breakpoint 1, main (argc=1, argv=0x7ff8c9a488) at system/core/logd/main.cpp:427
Below is an example of doing the same but with strace
stop logdsetprop ctl.sigstop_on logdstart logdps -e | grep logd> logd 4343 1 18156 1684 do_signal_stop 538280 T initstrace -p 4343(From a different shell)kill -SIGCONT 4343> strace runs
Host Init Script Verification
Init scripts are checked for correctness during build time. Specifically the below is checked.
1) Well formatted action, service and import sections, e.g. no actions without a preceding ‘on’ line, and no extraneous lines after an ‘import’ statement. 2) All commands map to a valid keyword and the argument count is within the correct range. 3) All service options are valid. This is stricter than how commands are checked as the service options’ arguments are fully parsed, e.g. UIDs and GIDs must resolve.
There are other parts of init scripts that are only parsed at runtime and therefore not checked during build time, among them are the below.
1) The validity of the arguments of commands, e.g. no checking if file paths actually exist, if SELinux would permit the operation, or if the UIDs and GIDs resolve. 2) No checking if a service exists or has a valid SELinux domain defined 3) No checking if a service has not been previously defined in a different init script.
Early Init Boot Sequence
The early init boot sequence is broken up into three stages: first stage init, SELinux setup, and second stage init.
First stage init is responsible for setting up the bare minimum requirements to load the rest of the system. Specifically this includes mounting /dev, /proc, mounting ‘early mount’ partitions (which needs to include all partitions that contain system code, for example system and vendor), and moving the system.img mount to / for devices with a ramdisk.
Note that in Android Q, system.img always contains TARGET_ROOT_OUT and always is mounted at / by the time first stage init finishes. Android Q will also require dynamic partitions and therefore will require using a ramdisk to boot Android. The recovery ramdisk can be used to boot to Android instead of a dedicated ramdisk as well.
First stage init has three variations depending on the device configuration:
1) For system-as-root devices, first stage init is part of /system/bin/init and a symlink at /init points to /system/bin/init for backwards compatibility. These devices do not need to do anything to mount system.img, since it is by definition already mounted as the rootfs by the kernel.
2) For devices with a ramdisk, first stage init is a static executable located at /init. These devices mount system.img as /system then perform a switch root operation to move the mount at /system to /. The contents of the ramdisk are freed after mounting has completed.
3) For devices that use recovery as a ramdisk, first stage init it contained within the shared init located at /init within the recovery ramdisk. These devices first switch root to /first_stage_ramdisk to remove the recovery components from the environment, then proceed the same as 2). Note that the decision to boot normally into Android instead of booting into recovery mode is made if androidboot.force_normal_boot=1 is present in the kernel commandline.
Once first stage init finishes it execs /system/bin/init with the “selinux_setup” argument. This phase is where SELinux is optionally compiled and loaded onto the system. selinux.cpp contains more information on the specifics of this process.
Lastly once that phase finishes, it execs /system/bin/init again with the “second_stage” argument. At this point the main phase of init runs and continues the boot process via the init.rc scripts.
qiushao@qiushao-pc:~$ uname -a Linux qiushao-pc 5.3.0-28-generic #30~18.04.1-Ubuntu SMP Fri Jan 17 06:14:09 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux qiushao@qiushao-pc:~$
qiushao@qiushao-pc:~/Downloads/kernel$ ls linux-headers-5.4.23-050423_5.4.23-050423.202002281329_all.deb linux-image-unsigned-5.4.23-050423-generic_5.4.23-050423.202002281329_amd64.deb linux-headers-5.4.23-050423-generic_5.4.23-050423.202002281329_amd64.deb linux-modules-5.4.23-050423-generic_5.4.23-050423.202002281329_amd64.deb qiushao@qiushao-pc:~/Downloads/kernel$ qiushao@qiushao-pc:~/Downloads/kernel$ sudo dpkg -i *.deb (Reading database ... 244666 files and directories currently installed.) Preparing to unpack linux-headers-5.4.23-050423_5.4.23-050423.202002281329_all.deb ... Unpacking linux-headers-5.4.23-050423 (5.4.23-050423.202002281329) over (5.4.23-050423.202002281329) ... Preparing to unpack linux-headers-5.4.23-050423-generic_5.4.23-050423.202002281329_amd64.deb ... Unpacking linux-headers-5.4.23-050423-generic (5.4.23-050423.202002281329) over (5.4.23-050423.202002281329) ... Preparing to unpack linux-image-unsigned-5.4.23-050423-generic_5.4.23-050423.202002281329_amd64.deb ... Unpacking linux-image-unsigned-5.4.23-050423-generic (5.4.23-050423.202002281329) over (5.4.23-050423.202002281329) ... Preparing to unpack linux-modules-5.4.23-050423-generic_5.4.23-050423.202002281329_amd64.deb ... Unpacking linux-modules-5.4.23-050423-generic (5.4.23-050423.202002281329) over (5.4.23-050423.202002281329) ... Setting up linux-headers-5.4.23-050423 (5.4.23-050423.202002281329) ... Setting up linux-headers-5.4.23-050423-generic (5.4.23-050423.202002281329) ... Setting up linux-modules-5.4.23-050423-generic (5.4.23-050423.202002281329) ... Setting up linux-image-unsigned-5.4.23-050423-generic (5.4.23-050423.202002281329) ... Processing triggers for linux-image-unsigned-5.4.23-050423-generic (5.4.23-050423.202002281329) ... /etc/kernel/postinst.d/initramfs-tools: update-initramfs: Generating /boot/initrd.img-5.4.23-050423-generic W: Possible missing firmware /lib/firmware/rtl_nic/rtl8125a-3.fw for module r8169 I: The initramfs will attempt to resume from /dev/nvme0n1p4 I: (UUID=5d386fca-a168-4aae-9b13-425eae5932ea) I: Set the RESUME variable to override this. /etc/kernel/postinst.d/zz-update-grub: Sourcing file `/etc/default/grub' Generating grub configuration file ... Found linux image: /boot/vmlinuz-5.4.23-050423-generic Found initrd image: /boot/initrd.img-5.4.23-050423-generic Found linux image: /boot/vmlinuz-5.3.0-28-generic Found initrd image: /boot/initrd.img-5.3.0-28-generic Found linux image: /boot/vmlinuz-5.0.0-37-generic Found initrd image: /boot/initrd.img-5.0.0-37-generic Found Manjaro Linux (19.0.1) on /dev/nvme0n1p3 Adding boot menu entry for EFI firmware configuration done qiushao@qiushao-pc:~/Downloads/kernel$ qiushao@qiushao-pc:~/Downloads/kernel$ reboot
3. 重启验证
重启后，查看一下内核的版本信息：
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qiushao@qiushao-pc:~$ uname -a Linux qiushao-pc 5.3.0-28-generic #30~18.04.1-Ubuntu SMP Fri Jan 17 06:14:09 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux qiushao@qiushao-pc:~$
menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-697f7639-b38d-4e6c-a994-d36c5542dae5' { recordfail load_video gfxmode $linux_gfx_mode insmod gzio if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi insmod part_gpt insmod ext2 if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root 697f7639-b38d-4e6c-a994-d36c5542dae5 else search --no-floppy --fs-uuid --set=root 697f7639-b38d-4e6c-a994-d36c5542dae5 fi linux /boot/vmlinuz-5.4.23-050423-generic root=UUID=697f7639-b38d-4e6c-a994-d36c5542dae5 ro quiet splash $vt_handoff initrd /boot/initrd.img-5.4.23-050423-generic }
我们看到最后两行配置是内核相关的，其中指定了使用哪个版本的内核来启动系统。关于 grub 的知识，是 Linux 通用的，任何发行版都是一样的。
解决方案很简单，先进入 manjaro 系统先，然后执行这个命令更新 grub 启动信息：
1
sudo update-grub
更新完之后， reboot 重启进入 ubuntu 再看看内核的版本：
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qiushao@qiushao-pc:~$ uname -a Linux qiushao-pc 5.4.23-050423-generic #202002281329 SMP Fri Feb 28 18:33:31 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux qiushao@qiushao-pc:~$
