最近被安排来搞定android、ios、mac、windows下的webrtc、ffmpeg和x264的编译问题。
除了由于webrtc配置工程的问题在windows下我自己的搭建环境无法使用，最终求助于之前使用的虚拟机环境以外，android下的webrtc都比较顺利，同样也是编译anroid环境的和windows环境的ffmpeg，相对来说也是比较顺畅（虽然还是出现了一些坎坷）。
但在Mac环境下编译webrtc、ffmpeg和x264就没有那么幸运了。简直就是人间地狱，首先说明一下，这个Mac机原先是有其他开发者在上面编译成功过这三个工程的，到我之后就开始出现了一大堆问题（当然也有可能我用的是用户新帐号的缘故）。
人间地狱的开始
- 先说一说编译webrtc遇到的坑爹问题。由于webrtc编译环境我们只输出静态库，并不输出一个framework或者app，所以并不需要关心太多app层面的问题（如证书相关）。虽知道在webrtc的gyp检查项目中会对证书冲突做检查，由于机器中存在多个证书，导致gyp阶段无法生成正确的编译配置参数。导致折腾了一周，最后才发现和证书有关。虽然这个问题和gyp有一定的关系，但也只是我对mac上编译和交叉编译的被坑的起点。
- 接着是x264和ffmpeg编译时，由于给我的工程之前都是能够成功编译的，现如今拿过来，除了Mac平台可以通过以外，真机和模拟器都不行。折腾来折腾去几天，最后发现是clang去找依赖的时候找错了，找了mac的依赖环境，而不是去找iphoneos的依赖，然后怎么调都没用。很是坑爹，就拿网上的现成脚本来跑也是不行。
最后去查config.log，发现一堆错误，其中ffmpeg的错误还有一个叫做gas-preprocessor.pl的执行错误，由于是通过git直接从网上拿下来的脚本，在没有任何修改的情况下，通过sftp发到mac里面，给了执行权限之后通过命令行直接执行一点问题都没有，但通过configure执行时就一直报没有权限的错，怎么也想不明白；后来试着用curl拿文件，居然通了。当时我就估计如果不是字符集的问题，就是权限标记位的问题。
接着再继续修改关于依赖的问题，仅仅一个交叉编译工具clang，居然在不同的工程里面对同一个路径参数能够出现多种不同的行为，后来还特意看了一下clang是不是GNU开源社区的代码，通过–version看到的内容如下：
Apple LLVM version 8.0.0 (clang-800.0.42.1)
Target: x86_64-apple-darwin16.4.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
可见这个坑是苹果自己的。可能是由于命令行的长度的不同，导致解析命令行的bug？或者其他什么坑爹问题？反正我是不知道了，近几年开始苹果的产品也不见得有多少优势了，正在被一点点拉小差距。如果不是为了混口饭吃，苹果的任何产品我真的不想去碰！
不知道什么时候，vps上面的mysql不启动了，后来果断来了个apt-get upgrade。还是无解，发现mysql.err为空。怎么弄头看不明白。
后来查看/var/log/syslog，发现如下记录:
May 28 07:36:53 emhct mysqld: 160528 7:36:53 [Warning] Using unique option prefix key_buffer instead of key_buffer_size is deprecated and will be removed in a future release. P$
May 28 07:36:53 emhct mysqld: 160528 7:36:53 [Note] /usr/sbin/mysqld (mysqld 5.5.49-0+deb7u1) starting as process 2208 …
May 28 07:36:53 emhct mysqld: 160528 7:36:53 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future$
May 28 07:36:53 emhct mysqld: 160528 7:36:53 [Note] Plugin ‘FEDERATED’ is disabled.
May 28 07:36:53 emhct mysqld: 160528 7:36:53 InnoDB: The InnoDB memory heap is disabled
May 28 07:36:53 emhct mysqld: 160528 7:36:53 InnoDB: Mutexes and rw_locks use GCC atomic builtins
May 28 07:36:53 emhct mysqld: 160528 7:36:53 InnoDB: Compressed tables use zlib 1.2.7
May 28 07:36:53 emhct mysqld: 160528 7:36:53 InnoDB: Using Linux native AIO
May 28 07:36:53 emhct mysqld: 160528 7:36:53 InnoDB: Initializing buffer pool, size = 128.0M
May 28 07:36:53 emhct mysqld: 160528 7:36:53 InnoDB: Completed initialization of buffer pool
May 28 07:36:53 emhct mysqld: 160528 7:36:53 InnoDB: highest supported file format is Barracuda.
May 28 07:36:53 emhct mysqld: InnoDB: The log sequence number in ibdata files does not match
May 28 07:36:53 emhct mysqld: InnoDB: the log sequence number in the ib_logfiles!
May 28 07:36:53 emhct mysqld: 160528 7:36:53 InnoDB: Database was not shut down normally!
May 28 07:36:53 emhct mysqld: InnoDB: Starting crash recovery.
May 28 07:36:53 emhct mysqld: InnoDB: Reading tablespace information from the .ibd files…
May 28 07:36:53 emhct mysqld: InnoDB: Restoring possible half-written data pages from the doublewrite
May 28 07:36:53 emhct mysqld: InnoDB: buffer…
May 28 07:36:53 emhct mysqld: 160528 7:36:53 InnoDB: ERROR: We were only able to scan the log up to
May 28 07:36:53 emhct mysqld: InnoDB: 16701665280, but a checkpoint was at 16701665306.
May 28 07:36:53 emhct mysqld: InnoDB: It is possible that the database is now corrupt!
May 28 07:36:53 emhct mysqld: 160528 7:36:53 InnoDB: Assertion failure in thread 3064944864 in file fut0lst.ic line 83
May 28 07:36:53 emhct mysqld: InnoDB: Failing assertion: addr.page == FIL_NULL || addr.boffset >= FIL_PAGE_DATA
mysql居然crash了，后来网上了一下，发现好像是innodb顺坏了，简单扫描了mysql官方文档，看的云里雾里。
最终，把mysql数据库存放目录下的ibdata1、ib_*文件删除后，mysql正常启动。
这个脚本的原型来自之前提到的db备份脚本，但做了一些改动略有不同。
这次的脚本支持逗号分隔的kv输入，具体输入文本格式如下
+------------------+--------------+----------------+
| folder full path | separator(,) | folder descript|
+------------------+--------------+----------------+
| /var/aaaaa/ | , | aaaa11111 |
+------------------+--------------+----------------+
发送到邮箱的标题命名：web_bak_${folder descript}_${data}
具体shell代码如下：
#!/bin/bash
#need 2 var
if (($# != 2)); then
echo "need input [Web Site Name Full Path in File] [mode]"
echo "mode -> 0, <Web Site Name Full Path in File> read!"
echo "mode -> 1, do Web Site bak!"
exit;
fi
if (($2 < 0 && $2 > 1)); then
echo "err mode!"
exit
fi
#filter some lines:
# 1. pure tab line
# 2. pure \r\n
# 3. pure space line
WebSiteFullPathInFilePath=$1
sed /^[[:space:]]*$/d $WebSiteFullPathInFilePath > $WebSiteFullPathInFilePath".tmp"
####################################################
#pre-info
#
# +----------+--------------+-------------+
# | fullpath | separator(,) | description |
# +----------+--------------+-------------+
#
####################################################
loop_count=0
bak_WebSiteFullPathInFilePath_target=1
bak_WebSiteDescriptionFilePath_target=1
echo "WebSiteFullPathInFilePath: "$WebSiteFullPathInFilePath" <<<>>> WebSiteFullPathInFilePath_tmp: "$WebSiteFullPathInFilePath".tmp"
echo ============ output all web site info $(date +"%Y%m%d") ==================
while read -r line
do
#echo $line
stringlen=${#line}
keyend=$(expr index $line ',')
key=${line:0:$keyend-1}
value=${line:$keyend:$stringlen-$keyend}
#echo "stringlen: "$stringlen" keyend: "$keyend" key: "$key" value: "$value
bak_WebSiteFullPathInFilePath_target[loop_count]=$key
bak_WebSiteDescriptionFilePath_target[loop_count]=$value
((loop_count++))
done < $WebSiteFullPathInFilePath".tmp"
i=0
for ((;i<$loop_count && $loop_count>0;i++))
do
echo "website name: "${bak_WebSiteDescriptionFilePath_target[$i]}
echo -e "\twebsite full path: "${bak_WebSiteFullPathInFilePath_target[$i]}"\n"
done
echo "total - "$i
echo ============ end ==================
if (($2 == 0)); then
echo "test over"
exit;
fi
if (($i<=0)); then
echo "don't have website full path!"
exit
fi
#do work
i=0
for ((;i<$loop_count && $loop_count>0;i++))
do
WebSiteFullPath=${bak_WebSiteFullPathInFilePath_target[$i]}
WebSiteDescription=${bak_WebSiteDescriptionFilePath_target[$i]}
BakName_tmp=website_bak_${WebSiteDescription}_$(date +"%Y%m%d")
#mkdir
mkdir /tmp/website_bak
mkdir /tmp/website_bak/${WebSiteDescription}
#del bak file before 3 days
rm -rf /tmp/website_bak/${WebSiteDescription}/website_bak_${WebSiteDescription}_$(date -d -3day +"%Y%m%d").tar.gz
#compact file
tar zcf /tmp/website_bak/${WebSiteDescription}/$BakName_tmp.tar.gz $WebSiteFullPath
#Send mail
mutt -s $BakName_tmp "email@163.com" -a /tmp/website_bak/${WebSiteDescription}/$BakName_tmp.tar.gz < /var/auto_script/emptytext.txt
done
同样作为定时任务，将命令执行放在crontab中
在创建自动任务之前需要安装的安装包：
cron
使用crontab来对当前用户的定时任务进行编辑
crontab -u //设定某个用户的cron服务，一般root用户在执行这个命令的时候需要此参数
crontab -l //列出当前(某个)用户cron服务的详细内容
crontab -r //删除当前(某个)用户的cron服务
crontab -e //编辑当前(某个)用户的cron服务
这里使用root创建的用户，所以直接在root用户下，执行crontab -e编辑好以后然后退出编辑器即可。
如果不放心还可以执行以下/etc/init.d/cron restart
编辑好以后的脚本如下
# Edit this file to introduce tasks to be run by cron.
#
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
#
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').#
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
#
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
#
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
#
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h dom mon dow command
25 22 * * 4 /var/auto_script/db_bak/dbbak.sh /var/auto_script/db_bak/dbname.txt 1 >> /var/auto_script/db_bak/autoworker_log.txt
其中的25代表时间的25分钟
22代表时间的22点
4代表每周星期4
/var/auto_script/db_bak/dbbak.sh /var/auto_script/db_bak/dbname.txt 1 >> /var/auto_script/db_bak/autoworker_log.txt 则是命令行
对于cron自身的配置来说，他的配置放在/etc/crontab，内容如下：
# /etc/crontab: system-wide crontab
# Unlike any other crontab you don't have to run the `crontab'
# command to install the new version when you edit this file
# and files in /etc/cron.d. These files also have username fields,
# that none of the other crontabs do.
SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
# m h dom mon dow user command
51 * * * * root cd / && run-parts --report /etc/cron.hourly
40 1 * * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
48 5 * * 7 root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
28 2 23 * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
#
对于cron的配置来说，尽量不要去修改，网上有些文章说，如果要执行周期性任务，可以到/etc/cron.*目录下保存脚本，我这边看到的是，大部分都是系统类任务；最好不要去这样做。混淆了脚本的分类很麻烦
首先需要安装这几个包：
mutt、uuencode、sendmail
脚本如下：
#!/bin/bash
#need 2 var
if (($# != 2)); then
echo "need input [DBNamefile] [mode]"
echo "mode -> 0, test DBNamefile read!"
echo "mode -> 1, do DB bak!"
exit;
fi
if (($2 < 0 && $2 > 1)); then
echo "err mode!"
exit
fi
#filter some lines:
# 1. pure tab line
# 2. pure \r\n
# 3. pure space line
DBNameFilePath=$1
sed /^[[:space:]]*$/d $DBNameFilePath > $DBNameFilePath".tmp"
#pre-info
loop_count=0
bak_DBName_target=1
echo "DBNameFilePath: "$DBNameFilePath" <<<>>> DBNameFilePath_tmp: "$DBNameFilePath".tmp"
echo ============ output all db Name $(date +"%Y%m%d") ==================
while read -r line
do
#echo $line
bak_DBName_target[loop_count]=$line
((loop_count++))
done < $DBNameFilePath".tmp"
i=0
for ((;i<$loop_count && $loop_count>0;i++))
do
echo ${bak_DBName_target[$i]}
done
echo "total - "$i
echo ============ end ==================
if (($2 == 0)); then
echo "test over"
exit;
fi
if (($i<=0)); then
echo "empty db name!"
exit
fi
#do work
i=0
for ((;i<$loop_count && $loop_count>0;i++))
do
DBName_Tmp=${bak_DBName_target[$i]}
DataBakName_tmp=Data_bak_${DBName_Tmp}_$(date +"%Y%m%d")
#del db before 3 days
rm -rf /home/backup/Data_$(date -d -3day +"%Y%m%d").tar.gz
#expory mysql db
mysqldump -u root -ppassword $DBName_Tmp > /tmp/mysql_db_bak/$DataBakName_tmp.sql
#compact db file
tar zcf /tmp/mysql_db_bak/$DataBakName_tmp.tar.gz /tmp/mysql_db_bak/$DataBakName_tmp.sql
#del temporary sql
rm -rf /tmp/mysql_db_bak/$DataBakName_tmp.sql
#Send mail
mutt -s $DataBakName_tmp "email@163.com" -a /tmp/mysql_db_bak/$DataBakName_tmp.tar.gz < mailbody.txt
done
上面脚本的用法是:
./a.sh 1.txt 0
1.txt是保存要备份数据库名称的文件。