Check getgrgid(3) return value to avoid crash
getgrgid(3) can fail and return a NULL group, for example on some misconfigurations. Don't dereference gr without checking it first.
Fixes #134 (closed)
getgrgid(3) can fail and return a NULL group, for example on some misconfigurations. Don't dereference gr without checking it first.
Fixes #134 (closed)