LD_DEBUG 命令

最新推荐文章于 2024-12-16 13:34:01 发布

原创最新推荐文章于 2024-12-16 13:34:01 发布 · 1.1k 阅读

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CC 4.0 BY-SA版权

文章标签：

#file #memcached #search #library #path #object

本文介绍如何通过设置LD_DEBUG环境变量来诊断并解决memcached在运行时找不到libevent-2.0.so.5库文件的问题，并给出了创建正确软链接的方法。

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LD_DEBUG是glibc中的 loader 设置的一个环境变量，主要的应用便于定位加载库模块时出现的问题

以memcached安装过程中遇到的问题为例：

命令： /usr/local/bin/memcached -p 11211 -m 64m -vv
错误：/usr/local/bin/memcached: error while loading shared libraries: libevent-2.0.so.5: cannot open shared object file: No such file or directory

使用LD_DEBUG显示库寻找信息

LD_DEBUG=libs /usr/local/bin/memcached -vv
     15759:    find library=libevent-2.0.so.5 [0]; searching
     15759:    search cache=/etc/ld.so.cache
     15759:    search path=/lib64/tls/x86_64:/lib64/tls:/lib64/x86_64:/lib64:/usr/lib64/tls/x86_64:/usr/lib64/tls:/usr/lib64/x86_64:/usr/lib64           (system search path)
     15759:    trying file=/lib64/tls/x86_64/libevent-2.0.so.5
     15759:    trying file=/lib64/tls/libevent-2.0.so.5
     15759:    trying file=/lib64/x86_64/libevent-2.0.so.5
     15759:    trying file=/lib64/libevent-2.0.so.5
     15759:    trying file=/usr/lib64/tls/x86_64/libevent-2.0.so.5
     15759:    trying file=/usr/lib64/tls/libevent-2.0.so.5
     15759:    trying file=/usr/lib64/x86_64/libevent-2.0.so.5
     15759:    trying file=/usr/lib64/libevent-2.0.so.5

最后一行可以看出，memcached去/usr/lib64目录下寻找libevent-2.0.so.5，先定位libevent-2.0.so.5实际目录

命令：whereis libevent-2.0.so.5

结果：libevent-2.0.so: /usr/lib/libevent-2.0.so.5

这时候需要将做一个软连接

命令：ln -s /usr/lib/libevent-2.0.so.5 /usr/lib64/libevent-2.0.so.5