QtWidgets programs on Linux access things from the system

[DavidEGrayson]

There is some code in Qt or the libraries it uses that looks for files in fixed locations on the user's system at run time. For maximum reliability, it should not do that. I used strace on the Tic Configuration Utility compiled for linux-x86 by nixcrpkgs and grepped for /usr:

stat64("/usr/share/upstart/xdg/QtProject/qtlogging.ini", 0xffc6ab50) = -1 ENOENT (No such file or directory)
stat64("/usr/share/X11/xkb", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
stat64("/usr/share/ubuntu/mime/mime.cache", 0xffc6a9f0) = -1 ENOENT (No such file or directory)
stat64("/usr/share/gnome/mime/mime.cache", 0xffc6a9f0) = -1 ENOENT (No such file or directory)
stat64("/usr/local/share/mime/mime.cache", 0xffc6a9f0) = -1 ENOENT (No such file or directory)
stat64("/usr/share/mime/mime.cache", {st_mode=S_IFREG|0644, st_size=125732, ...}) = 0
open("/usr/share/mime/mime.cache", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 7
stat64("/usr/share/mime/mime.cache", {st_mode=S_IFREG|0644, st_size=125732, ...}) = 0
stat64("/usr/share/ubuntu/mime/image/vnd.microsoft.icon.xml", 0xffc6aa20) = -1 ENOENT (No such file or directory)
stat64("/usr/share/gnome/mime/image/vnd.microsoft.icon.xml", 0xffc6aa20) = -1 ENOENT (No such file or directory)
stat64("/usr/local/share/mime/image/vnd.microsoft.icon.xml", 0xffc6aa20) = -1 ENOENT (No such file or directory)
stat64("/usr/share/mime/image/vnd.microsoft.icon.xml", {st_mode=S_IFREG|0644, st_size=1475, ...}) = 0
open("/usr/share/mime/image/vnd.microsoft.icon.xml", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 8
stat64("/usr/share/ubuntu/mime/image/vnd.microsoft.icon.xml", 0xffc6aa70) = -1 ENOENT (No such file or directory)
stat64("/usr/share/gnome/mime/image/vnd.microsoft.icon.xml", 0xffc6aa70) = -1 ENOENT (No such file or directory)
stat64("/usr/local/share/mime/image/vnd.microsoft.icon.xml", 0xffc6aa70) = -1 ENOENT (No such file or directory)
stat64("/usr/share/mime/image/vnd.microsoft.icon.xml", {st_mode=S_IFREG|0644, st_size=1475, ...}) = 0
open("/usr/share/mime/image/vnd.microsoft.icon.xml", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 8

I already noticed that Qt is being compiled with the -DDFLT_XKB_CONFIG_ROOT=\"/usr/share/X11/xkb\" flag but I have not looked into why.

[DavidEGrayson]

I also noticed it trying to access /nix/store/blahblah/qtlogging.ini.