lib/getugroups overflow check

[Paul Eggert]

I installed this patch for a very unlikely problem: more than INT_MAX groups.

2004-07-28  Paul Eggert  <address@hidden>

        * getugroups.c: Include <errno.h>.
        (EOVERFLOW): Define if not defined.
        (getgroups): Return -1 with errno=EOVERFLOW if an integer overflow
        occurs.

Index: getugroups.c
===================================================================
RCS file: /home/eggert/coreutils/cu/lib/getugroups.c,v
retrieving revision 1.12
retrieving revision 1.13
diff -p -u -r1.12 -r1.13
--- getugroups.c        10 Sep 2003 08:45:43 -0000      1.12
+++ getugroups.c        28 Jul 2004 19:41:08 -0000      1.13
@@ -1,5 +1,7 @@
 /* getugroups.c -- return a list of the groups a user is in
-   Copyright (C) 1990, 1991, 1998, 1999, 2000, 2003 Free Software Foundation.
+
+   Copyright (C) 1990, 1991, 1998, 1999, 2000, 2003, 2004 Free
+   Software Foundation.
 
    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
@@ -29,6 +31,11 @@
 # include <unistd.h>
 #endif
 
+#include <errno.h>
+#ifndef EOVERFLOW
+# define EOVERFLOW EINVAL
+#endif
+
 /* setgrent, getgrent, and endgrent are not specified by POSIX.1,
    so header files might not declare them.
    If you don't have them at all, we can't implement this function.
@@ -88,6 +95,11 @@ getugroups (int maxcount, GETGROUPS_T *g
                  grouplist[count] = grp->gr_gid;
                }
              count++;
+             if (count < 0)
+               {
+                 errno = EOVERFLOW;
+                 return -1;
+               }
            }
        }
     }