linux 查看可执行文件动态链接库相关信息

ldd <可执行文件名><wbr><wbr><wbr><wbr><wbr><wbr>查看可执行文件链接了哪些<wbr>系统动态链接库<br> nm &lt;可执行文件名&gt;<wbr><wbr><wbr><wbr><wbr><wbr>查看可执行文件里面有哪些符号<br> strip &lt;可执行文件名&gt;<wbr><wbr><wbr><wbr><wbr>去除符号表可以给可执行文件瘦身<br> 如果我们想从可执行程序里面提取出来一点什么文本信息的话，还可以用strings命令<br> strings &lt;可执行文件名&gt;<br><br><br><p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> Linux操作系统上面的动态共享库大致分为三类：</p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> 1、操作系统级别的共享库和基础的系统工具库</p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> 比方说libc.so, libz.so, libpthread.so等等，这些系统库会被放在/lib和/usr/lib目录下面，如果是64位操作系统，还会有/lib64和/usr /lib64目录。如果操作系统带有图形界面，那么还会有/usr/X11R6/lib目录，如果是64位操作系统，还有/usr/X11R6 /lib64目录。此外还可能有其他特定Linux版本的系统库目录。</p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> 这些系统库文件的完整和版本的正确，确保了Linux上面各种程序能够正常的运行。</p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> 2、应用程序级别的系统共享库</p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> 并非操作系统自带，但是可能被很多应用程序所共享的库，一般会被放在/usr/local/lib和/usr/local/lib64这两个目录下 面。很多你自行编译安装的程序都会在编译的时候自动把/usr/local/lib加入gcc的-L参数，而在运行的时候自动到/usr/local /lib下面去寻找共享库。</p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> 以上两类的动态共享库，应用程序会自动寻找到他们，并不需要你额外的设置和担心。这是为什么呢？ 因为以上这些目录默认就被加入到动态链接程序的搜索路径里面了。Linux的系统共享库搜索路径定义在/etc/ld.so.conf这个配置文件里面。 这个文件的内容格式大致如下：</p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> <br> /usr/X11R6/lib64<wbr><wbr><br> /usr/X11R6/lib<wbr><wbr><br> /usr/local/lib<wbr><wbr><br> /lib64<wbr><wbr><br> /lib<wbr><wbr><br> /usr/lib64<wbr><wbr><br> /usr/lib<wbr><wbr><br> /usr/local/lib64<wbr><wbr><br> /usr/local/ImageMagick/lib</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> 假设我们自己编译安装的ImageMagick图形库在/usr/local/ImageMagick目录下面，并且希望其他应用程序都可以使用 ImageMagick的动态共享库，那么我们只需要把/usr/local/ImageMagick/lib目录加入/etc/ld.so.conf文 件里面，然后执行：ldconfig 命令即可。</p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> ldcofig将搜索以上所有的目录，为共享库建立一个缓存文件/etc/ld.so.cache。为了确认ldconfig已经搜索到ImageMagick的库，我们可以用上面介绍的strings命令从ld.so.cache里面抽取文本信息来检查一下：<br><br> strings /etc/ld.so.cache | grep ImageMagick<wbr><wbr><br></wbr></wbr></p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> <br> 输出结果为：<br><br> /usr/local/ImageMagick/lib/libWand.so.10<wbr><wbr><br> /usr/local/ImageMagick/lib/libWand.so<wbr><wbr><br> /usr/local/ImageMagick/lib/libMagick.so.10<wbr><wbr><br> /usr/local/ImageMagick/lib/libMagick.so<wbr><wbr><br> /usr/local/ImageMagick/lib/libMagick++.so.10<wbr><wbr><br> /usr/local/ImageMagick/lib/libMagick++.so<br> 已经成功了！</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> 3、应用程序独享的动态共享库</p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> 有很多共享库只被特定的应用程序使用，那么就没有必要加入系统库路径，以免应用程序的共享库之间发生版本冲突。因此Linux还可以通过设置环境变 量LD_LIBRARY_PATH来临时指定应用程序的共享库搜索路径，就像我们上面举的那个例子一样，我们可以在应用程序的启动脚本里面预先设置 LD_LIBRARY_PATH，指定本应用程序附加的共享库搜索路径，从而让应用程序找到它。</p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> <br></p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> <br></p> <p style="margin-top:0px; margin-right:0px; margin-bottom:5px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; list-style-type:none; list-style-position:initial; word-wrap:normal; word-break:normal; line-height:21px"> <a href="http://blog.sina.com.cn/s/blog_67eb1f2f0100mgd8.html" target="_blank">文章引自</a></p> </wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>