diff options
Diffstat (limited to 'lib/getgroups.c')
-rw-r--r-- | lib/getgroups.c | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/lib/getgroups.c b/lib/getgroups.c new file mode 100644 index 0000000..615bd4f --- /dev/null +++ b/lib/getgroups.c @@ -0,0 +1,66 @@ +/* provide consistent interface to getgroups for systems that don't allow N==0 + + Copyright (C) 1996, 1999, 2003, 2006 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* written by Jim Meyering */ + +#include <config.h> + +#include <stdio.h> +#include <sys/types.h> +#include <errno.h> +#include <stdlib.h> + +#include "xalloc.h" + +/* On at least Ultrix 4.3 and NextStep 3.2, getgroups (0, 0) always fails. + On other systems, it returns the number of supplemental groups for the + process. This function handles that special case and lets the system- + provided function handle all others. */ + +int +getgroups (int n, GETGROUPS_T *group) +{ + int n_groups; + GETGROUPS_T *gbuf; + int saved_errno; + +#undef getgroups + + if (n != 0) + return getgroups (n, group); + + n = 20; + while (1) + { + /* No need to worry about address arithmetic overflow here, + since the ancient systems that we're running on have low + limits on the number of secondary groups. */ + gbuf = xmalloc (n * sizeof *gbuf); + n_groups = getgroups (n, gbuf); + if (n_groups < n) + break; + free (gbuf); + n += 10; + } + + saved_errno = errno; + free (gbuf); + errno = saved_errno; + + return n_groups; +} |