更改当前流程环境的LD_LIBRARY_PATH [英] Change current process environment's LD_LIBRARY_PATH

问题描述

是否可以更改当前进程的环境变量？

更具体地说，在python脚本中，我想更改 LD_LIBRARY_PATH ，以便在导入一个模块'x'时取决于一些 xyz.so ， xyz.so 取自LD_LIBRARY_PATH中的给定路径

是否有任何其他方式动态更改加载库的路径？

编辑：我认为我需要提到，我已经尝试过像
os.environ [LD_LIBRARY_PATH] = mypath
os.putenv（'LD_LIBRARY_PATH'，mypath）

但这些修改了env。对于生成的子进程，不是当前进程，模块加载不考虑新的LD_LIBRARY_PATH

Edit2 ，所以问题是可以改变环境或图书馆装载机看到的东西，从那里加载？

解决方案

原因

  os.environ [LD_LIBRARY_PATH] = ... 
  

不工作很简单：这个环境变量控制Linux上的动态加载器（ ld-linux.so.2 ）的行为， ld.so.1 在Solaris），但加载程序只在进程启动时查看 LD_LIBRARY_PATH 。在之后的当前进程中更改 LD_LIBRARY_PATH 的值不起作用（就像这个问题说）。

你有一些选择：

A。如果你知道你需要从 / some / path 需要 xyz.so ，并控制python的执行脚本从一开始，然后简单地设置 LD_LIBRARY_PATH 为您的喜好（在检查它尚未设置后），并重新执行自己。这就是 Java 。

B。您可以在导入 x.so 导入 /some/path/xyz.so $ C>。当您导入 x.so 时，加载程序将发现它已经加载了 xyz.so ，并将使用已经加载的模块，而不是再次搜索。

C。如果您自己构建 x.so ，可以在其链接中添加 -Wl，-rpath = / some / path 行，然后导入 x.so 将导致加载程序在 / some / path 中查找依赖模块。 / p>

Is it possible to change environment variables of current process?

More specifically in a python script I want to change LD_LIBRARY_PATH so that on import of a module 'x' which depends on some xyz.so, xyz.so is taken from my given path in LD_LIBRARY_PATH

is there any other way to dynamically change path from where library is loaded?

Edit: I think I need to mention that I have already tried thing like os.environ["LD_LIBRARY_PATH"] = mypath os.putenv('LD_LIBRARY_PATH', mypath)

but these modify the env. for spawned sub-process, not the current process, and module loading doesn't consider the new LD_LIBRARY_PATH

Edit2, so question is can we change environment or something so the library loader sees it and loads from there?

解决方案

The reason

os.environ["LD_LIBRARY_PATH"] = ...

doesn't work is simple: this environment variable controls behavior of the dynamic loader (ld-linux.so.2 on Linux, ld.so.1 on Solaris), but the loader only looks at LD_LIBRARY_PATH once at process startup. Changing the value of LD_LIBRARY_PATH in the current process after that point has no effect (just as the answer to this question says).

You do have some options:

A. If you know that you are going to need xyz.so from /some/path, and control the execution of python script from the start, then simply set LD_LIBRARY_PATH to your liking (after checking that it is not already so set), and re-execute yourself. This is what Java does.

B. You can import /some/path/xyz.so via its absolute path before importing x.so. When you then import x.so, the loader will discover that it has already loaded xyz.so, and will use the already loaded module instead of searching for it again.

C. If you build x.so yourself, you can add -Wl,-rpath=/some/path to its link line, and then importing x.so will cause the loader to look for dependent modules in /some/path.

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