shm_open() and shm_unlink() truncate names with embedded null characters

[serhiy-storchaka]

Bug report

Posix functions shm_open() and shm_unlink() take a null terminated C strings using PyUnicode_AsUTF8AndSize(path, NULL) which returns a pointer to char buffer which can include embedded null characters. When interpreted as C strings they are terminated at embedded null characters.

Linked PRs

• gh-115886: Handle embedded null characters in shared memory name #115887
• [3.12] gh-115886: Handle embedded null characters in shared memory name (GH-115887) #115906
• [3.11] gh-115886: Handle embedded null characters in shared memory name (GH-115887) #115907