getgroups: do not trap on non-positive gidsetsize

First, we should never check the size of __s if __l == 0 since the
array is not going to be modified in that case.

Second, negative __l is a well-defined error case (EINVAL) and we
should never trap on a conforming code like this:

r = getgroups(-1, NULL);
if (r == -1)
  ...

An example of non-desired behaviour for negative __l is the gnulib
configure script which checks for getgroups(-1, ...) to catch some
ancient FreeBSD kernel bug. The conftest binary traps even on good
system (e.g. linux/musl) and the unnecessary getgroups wrapper is
enforced for any project that uses gnulib.

This patch also changes the size_t cast to avoid the explicit zero
extension on systems where size_t differs from unsigned int.

0 files changed, 0 insertions, 0 deletions