lib/ramfs: Implement new file timestamps

[andreittr]

Description of changes

This change implements setting the file times of newly created files to the current time, filling in a placeholder that previously would set the times to the epoch (i.e., 1970-01-01 00:00 UTC).

Prerequisite checklist

• Read the contribution guidelines regarding submitting new changes to the project;
• Tested your changes against relevant architectures and platforms;
• Ran the checkpatch.uk on your commit series before opening this PR;
• Updated relevant documentation.

Base target

• Architecture(s): N/A
• Platform(s): N/A
• Application(s): N/A

Additional configuration

Test with:

int f = open("file", O_WRONLY|O_CREAT, 0777);
fstat(f, &st);
printf("%ld %ld\n", st.st_atime, st.st_mtime);

[DeliaPavel]

Looks good to me!

Reviewed-by: Delia Pavel delia_maria.pavel@stud.acs.upb.ro

[adinamariav]

Looks good.
Reviewed-by: Adina-Maria Vaman adinamariav22@gmail.com

[razvand]

Approved-by: Razvan Deaconescu razvand@unikraft.io