Draft: nsenter Avoid unnecessary looping by keeping reference to each namespace #2387
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…pace Instead of having to go over the `namespace_files` array every time to access a certain namespace file just have a global variable to each one. This makes `open_namespace_fd` function much shorter as exact namespace can be passed exactly. Also `set_parent_user_ns_fd` no longer has to do a workaround the uninititialized read and can set the user namespace directly.
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It would be enough (and maybe more elegant) to define indexes for the namespaces array: enum {
FILE_NS_MNT,
FILE_NS_PID,
...
};
...
open_namespace_fd(&namespace_files[FILE_NS_MNT], optarg);Maybe we can also rename |
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Interesting. I will try using enum. |
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Instead of having to go over the
namespace_filesarray every time to access a certain namespace file just have a global variable to each one.This makes
open_namespace_fdfunction much shorter as exact namespace can be passed exactly.Also
set_parent_user_ns_fdno longer has to do a workaround the uninititialized read and can set the user namespace directly.The reason I looked in to reworking this is the commit 32c7870. The
set_parent_user_ns_fdhas a local variable that has to be set inside the for loop. Some code scanners mark it as a NULL de reference but that is impossible.Currently the variables are set from after the array initialization which makes it pretty brittle as if the
namespace_filesarray ever changes it will break the references. (maybe add some asserts?)Another way is to create the
namespace_fileglobal variables first and then create an array of pointers to them. The downside of that method is it would require a more complicated loop code.