iox-#625 set file lock directory to /tmp/

[elfenpiff]

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References

• Closes FileLock requires write access to root owned directory /var/lock/ #625

[codecov]

Codecov Report

Merging #626 (afec953) into master (5995747) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #626      +/-   ##
==========================================
- Coverage   72.89%   72.86%   -0.03%     
==========================================
  Files         312      312              
  Lines       10819    10819              
  Branches     1941     1941              
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- Hits         7886     7883       -3     
- Misses       2170     2172       +2     
- Partials      763      764       +1     

Flag	Coverage Δ
unittests	72.86% <ø> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
iceoryx_utils/source/posix_wrapper/timer.cpp	59.64% <0.00%> (-0.88%)	⬇️
...nternal/roudi/introspection/port_introspection.inl	71.89% <0.00%> (-0.73%)	⬇️
...ils/include/iceoryx_utils/internal/cxx/smart_c.inl	89.06% <0.00%> (+1.56%)	⬆️

[elBoberido]

just to unblock developers who are not using ubuntu but we need to check the impact of this on QNX

[mossmaurice]

According to the file system hierarchy standard defined by the Linux foundation, lock files shall be placed under /var/lock. Seems like your distribution decided to choose another location. Mac OS prefers /var/tmp/, this will be available with #598

QNX advises to use /var/lock, but in our experience so far, it depends to the image, that is created.

Could you please add this with an #ifdef for common platforms? installation.md#QNX currently states that /var/locks is used, in case you change it please update it there.

[elfenpiff]

@mossmaurice sorry I read your comment after I merged the pull request :( ... but I will handle this comment nevertheless.

According to the file system hierarchy standard defined by the Linux foundation, lock files shall be placed under /var/locks

This is correct but the access rights of /var/lock is in Gentoo, ArchLinux and OpenSuSe like the following:

drwxrwxr-x  5 root root    120 Mar 22 15:26 lock
# /var

This means the user which is starting RouDi has to be at least in the root group. On the other hand /tmp/ is for all users always read and writable and since the applications and roudi has started as an arbitrary user it is the perfect spot for the lock file in QNX, Mac OS and Linux. If you insist in using /var/lock for the lock file we have to do the following things.

1. Write #ifdef for the platforms, instead of using /tmp which works for every platform (except Windows of course).
2. Add a chapter in the installation.md on howto add the user which is executing roudi to the lock management group of Linux, Mac OS (this will be a pain) and QNX.

If you do not object I would let the directory be /tmp and would add this to the installation.md since the file system hierarchy standard states the directory structure of a linux system and not where an application has to store the files. I admit it would be best to use the folders accordingly but it seems that on some linux systems we do not have access to /var/lock but we will always have access to /tmp.

By the way this also goes for QNX. The QNX boards of the past where also exactly in this way configured that everything was read only and we only had write access to /tmp.