Ubuntu 20.04升级，Python 丢失 libffi.so

我最近把我的操作系统升级到了 Ubuntu 20.04 LTS。

现在，当我尝试在 Python 中导入 Numpy 这样的库时，会得到以下错误:

ImportError: libffi.so.6: cannot open shared object file: No such file or directory

我尝试安装 libffi软件包，但 apt 找不到它:

sudo apt-get install libffi
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package libffi
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最佳答案

It seems like I fixed it. I could be wrong, but here is what I think happened:

  1. Ubuntu 20.04 upgraded libffi6 to libffi7
  2. Python is still looking for libffi6

What I did to fix it :

Locate libffi.so.7 in your system

$ find /usr/lib -name "libffi.so*"

Create a simlink named libffi.so.6 that points to libffi.so.7:

sudo ln -s /usr/path/to/libffi.so.7 /usr/lib/path/to/libffi.so.6

UPDATE:

As noted by many users, this fix could have unintended consequences. The better way to do it is to reinstall python as @amichaud explained. This should be used as a last resort IF you're not using pyenv/virtualenv/etc in which case removing python will cause a lot of dependencies to be removed as well.

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If you are using pyenv, you should just uninstall the used python version and then reinstall it.

Example:

pyenv uninstall 3.7.4
pyenv install 3.7.4

It's cleaner and safer than renaming system library from my point of view.

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I am using Xubuntu 20.04 and recompiling the python version 3.7 did not work for me.

The way I solved this was to download the 19.10 version of the package from here: http://mirrors.kernel.org/ubuntu/pool/main/libf/libffi/libffi6_3.2.1-8_amd64.deb

and then installing it

sudo apt install ./libffi6_3.2.1-8_amd64.deb

This will unpack the libffi.so.6 and libffi.so.6.0.4 files to /usr/lib/x86_64-linux-gnu/. The libffi.so.6 file is just a link to libffi.so.6.0.4 in the same directory.

As far as I could see this does not overwrite any files so should be safe.

Ubuntu 22.04 additional step As per comment from pijing below, you need to run this command after installing the above:

apt install libffi-devel

Then recompile Python.

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Same problem for me

  1. Upgraded to Ubuntu 20
  2. pip didn't work anymore (same error)

What I did was:

  1. Delete the virtual env I was using
  2. Recreate it

Sure, I wasn't able to do a pip freeze to get save my dependencies (as pip didn't work), but fortunately I didn't care about them.

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I had the same problem (when I upgrded to Ubuntu 20.04) when I tried to run Jupyter Notebook.

Step 1) --> Just re-install python3.7.6 (the version I was using) :

$ cd path_to_python3.7_folder
  • Do again de installation process:
    $ ./configure --enable-optimizations
$ make
$ sudo make install

  1. Step 2: uninstall jupyter. I used pip3.7 uninstall ... See: How to uninstall Jupyter note book installed by pip3

  2. Step 3: Re-install jupyter again:

    $ pip3.7 install jupyterlab
$ pip3.7 install notebook

Try to run jupyter again. It should work.

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Ubuntu 20 has libffi7 installed instead. It's possible to install the previous version using coming from Ubuntu 19.10 (Eoan Ermine) download from here Or you can follow these commands

$ curl -LO http://archive.ubuntu.com/ubuntu/pool/main/libf/libffi/libffi6_3.2.1-8_amd64.deb


$ sudo dpkg -i libffi6_3.2.1-8_amd64.deb
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The libffi6 package may be downloaded and installed as follows:

Identify a source for apt from the list Download Page for libffi6 (I picked http://mirrors.kernel.org/ubuntu/ for instance)

Make a back up of /etc/apt/sources.list (just in case)

Edit /etc/apt/sources.list and add the line (I added it to the very end of the file) ands save the file

deb https://mirrors.kernel.org/ubuntu bionic main

Update to use the new repository

sudo apt update

Finally, install the package:

sudo apt install libffi6

Note that both libffi6 and libffi7 appear to coexist. (My Ubuntu version is 20.04)

$ sudo apt list | grep libffi[67]/


WARNING: apt does not have a stable CLI interface. Use with caution in scripts.


libffi6/bionic,now 3.2.1-8 amd64 [installed]
libffi7/focal,now 3.3-4 amd64 [installed,automatic]
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The problem with libffi can also be tackled with making a symlink: sudo ln -s /usr/path/to/libffi.so.8 /usr/lib/path/to/libffi.so.7 Then you get another error in xorg log concerning wayland. What helped me was to reinstall wayland and lib32-wayland. After that I could boot normally (although I use xorg in Cinnamon, but also have Gnome installed)

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Symbolic linking to higher version of existing libffi,(e.g. pointing 6 to 8 or 9) does NOT harm since libffi's interface is almost frozen up to 9 years from now.

Higher SO version such as 6,7 or 8, simply it's there to indicate minimum requirement in case of new feature availability such as ffi_tramp_is_present. libffi itself is totally backward compatible so far as of 2022.

Anyone can confirm this by browsing inc folder in https://github.com/libffi/libffi

So, if you are seeing this issue in Ubuntu 22, please feel free to create a symbolic link to highest version of so available in your distro.


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