PHP监控linux服务器负载

　　由于Web Server以及PHP的实现方式所限，我们在现实环境中很难利用PHP去调用一些Linux中需要root权限才能执行的程序，对此，我从网上找到另外一种方式来绕开这个限制。首先先写个c程序中转调用系统命令，然后用PHP去执行此c程序。

　　c程序

　　首先写个c文件，比如/usr/local/ismole/w.c

 

<ol class="dp-c">
<li class="alt"><span><span class="comment">//note 由于wordpress编辑器的原因，请将此代码中头文件多余的空格去除 </span> </span></li>
<li><span><span class="preprocessor">#include  </span> </span></li>
<li class="alt"><span><span class="preprocessor">#include  </span> </span></li>
<li><span><span class="preprocessor">#include  </span> </span></li>
<li class="alt"><span><span class="preprocessor">#include  </span><span> </span></span></li>
<li><span> </span></li>
<li class="alt">
<span class="keyword">int</span><span> main()  </span>
</li>
<li><span>{  </span></li>
<li class="alt"><span>    uid_t uid ,euid;  </span></li>
<li><span> </span></li>
<li class="alt">
<span>    </span><span class="comment">//note 获得当前的uid </span><span> </span>
</li>
<li><span>    uid = getuid();  </span></li>
<li class="alt">
<span>    </span><span class="comment">//note 获得当前euid </span><span> </span>
</li>
<li><span>    euid = geteuid();  </span></li>
<li class="alt"><span> </span></li>
<li>
<span>    </span><span class="comment">//note 交换这两个id </span><span> </span>
</li>
<li class="alt">
<span>    </span><span class="keyword">if</span><span>(setreuid(euid, uid))  </span>
</li>
<li>
<span>        perror(</span><span class="string">"setreuid"</span><span>);  </span>
</li>
<li class="alt"><span> </span></li>
<li>
<span>    </span><span class="comment">//note 执行将要执行linux系统命令 </span><span> </span>
</li>
<li class="alt">
<span>    system(</span><span class="string">"/usr/bin/w"</span><span>);  </span>
</li>
<li>
<span>    </span><span class="keyword">return</span><span> 0;  </span>
</li>
<li class="alt"><span>}  </span></li>
</ol>

　　//note 由于wordpress编辑器的原因，请将此代码中头文件多余的空格去除

　　编译该文件gcc -o ipt -Wall w.c，这时会在当前目录下生成程序w。

　　改变此程序的属主chmod u+s ./w。

　　PHP执行

　　文件内容如下，放在web目录下，访问就会输出当前的服务器负载情况。

 

<ol class="dp-c">
<li class="alt"><span><span></span></span></li>
<li>
<span class="comment">//note key的验证过程 </span><span> </span>
</li>
<li class="alt">
<span class="keyword">if</span><span>(</span><span class="vars">$key</span><span> != </span><span class="vars">$authkey</span><span>) {  </span>
</li>
<li>
<span class="comment">//        exit(key error); </span><span> </span>
</li>
<li class="alt"><span>}  </span></li>
<li><span> </span></li>
<li class="alt">
<span class="vars">$last_line</span><span> = </span><span class="func">exec</span><span>(</span><span class="string">/usr/local/ismole/w</span><span>, </span><span class="vars">$retval</span><span>);  </span>
</li>
<li><span> </span></li>
<li class="alt">
<span class="vars">$returnArray</span><span> = </span><span class="func">explode</span><span>(</span><span class="string">"load average: "</span><span>, </span><span class="vars">$retval</span><span>[0]);  </span>
</li>
<li>
<span class="vars">$returnString</span><span> = </span><span class="vars">$returnArray</span><span>[1];  </span>
</li>
<li class="alt"><span> </span></li>
<li>
<span class="func">echo</span><span> </span><span class="vars">$returnString</span><span>;  </span>
</li>
</ol>

　　按照上面的实例，我们可以用PHP来做任何我们想执行的Linux系统命令，SVN更新，服务器监控，备份，恢复，日常维护等等。比如《利用SVN搭建测试服务器》