今天给网站换服务器结果无法正常运行，一步步排查后发现是没有安装xxtea扩展导致加解密函数无法使用，于是就安装xxtea扩展
pecl install xxtea结果提示一堆警告加一个错误提示ERROR: failed to run 'phpize'
WARNING: channel "pecl.php.net" has updated its protocols, use "pecl channel-update pecl.php.net" to update
Warning: readlink() has been disabled for security reasons in OS/Guess.php on line 201
PHP Warning: readlink() has been disabled for security reasons in /usr/local/php/lib/php/OS/Guess.php on line 201
Warning: popen() has been disabled for security reasons in OS/Guess.php on line 254
PHP Warning: popen() has been disabled for security reasons in /usr/local/php/lib/php/OS/Guess.php on line 254
Warning: fgets() expects parameter 1 to be resource, null given in OS/Guess.php on line 255
PHP Warning: fgets() expects parameter 1 to be resource, null given in /usr/local/php/lib/php/OS/Guess.php on line 255
Warning: pclose() expects parameter 1 to be resource, null given in OS/Guess.php on line 264
PHP Warning: pclose() expects parameter 1 to be resource, null given in /usr/local/php/lib/php/OS/Guess.php on line 264
downloading xxtea-1.0.11.tgz ...
Starting to download xxtea-1.0.11.tgz (7,404 bytes)
.....done: 7,404 bytes
4 source files, building
running: phpize
Warning: popen() has been disabled for security reasons in PEAR/Builder.php on line 525
PHP Warning: popen() has been disabled for security reasons in /usr/local/php/lib/php/PEAR/Builder.php on line 525
ERROR: failed to run `phpize'于是开始疯狂的百度，百度给出的结果大概意思是在php.ini里将popen函数禁用了，只需要将php.ini里disable_functions的值里面的popen去掉即可
最初：
disable_functions = passthru,exec,system,chroot,chgrp,chown,shell_exec,proc_open,proc_get_status,`popen`,ini_alter,ini_restore,dl,openlog,syslog,readlink,symlink,popepassthru,stream_socket_server修改后:
disable_functions = passthru,exec,system,chroot,chgrp,chown,shell_exec,proc_open,proc_get_status,ini_alter,ini_restore,dl,openlog,syslog,readlink,symlink,popepassthru,stream_socket_server然后重启php-fpm
/etc/init.d/php-fpm restart再次安装xxtea扩展成功，重启php-fpm，网站正常运行！