posix: fix glob bugs with long login names
Current glob implementation allows unlimited user name for home
directory construction on GLOB_TILDE case. To accomplish it glob
either construct a name on stack if size are small enough (based
on current alloca_used) or in heap otherwise.
This patch simplifies storage allocation by using the same scratch
buffer for both get_rlogin_r and getpwnam_r.
This also syncs with gnulib commit
064df0b (glob: fix bugs with long
login names).
Checked on x86_64-linux-gnu and on a build using build-many-glibcs.py
for all major architectures.
* posix/glob.c (GET_LOGIN_NAME_MAX): Remove.
(glob): Use the same scratch buffer for both getlogin_r and
getpwnam_r. Don’t require preallocation of the login name. This
simplifies storage allocation, and corrects the handling of
long login names.