Fixing getgrouplist code to work on all supported systems

diff --git a/mcs/class/Mono.Posix/Mono.Unix.Native/Syscall.cs b/mcs/class/Mono.Posix/Mono.Unix.Native/Syscall.cs
index 8d8390391e1dd4789ffe47b9bd7ec7dc42d4918c..51491d3801428976b529902c3fb7284de45b7ef7 100644 (file)
--- a/mcs/class/Mono.Posix/Mono.Unix.Native/Syscall.cs
+++ b/mcs/class/Mono.Posix/Mono.Unix.Native/Syscall.cs
@@ -2198,24 +2198,26 @@ namespace Mono.Unix.Native {
         
                public static Group [] getgrouplist (string username)
                {
+                       if (String.IsNullOrEmpty(username))
+                               return new Group[0];
                        // Syscall to getpwnam to retrieve user uid
                        Passwd pw = Syscall.getpwnam (username);
                        if (pw == null) 
                                return new Group [0];
-                       // initialising the lngroups by 1 to get the group count
+                       // initializing ngroups by 1 to get the group count
                        int ngroups = 1;
+                       int res = -1;
                        // allocating buffer to store group uid's
                        uint [] groups = new uint [ngroups];
-                       int res = sys_getgrouplist (username, pw.pw_gid, groups, ref ngroups);
-                       if (res == -1) {
-                               // using value ngroups to resize buffer.
-                               Array.Resize(ref groups, ngroups);
+                       do {
                                res = sys_getgrouplist (username, pw.pw_gid, groups, ref ngroups);
-                               if (res == -1) 
-                                       return new Group [0];
+                               if (res == -1) {
+                                       ngroups *=2;
+                                       Array.Resize(ref groups, ngroups);
+                               }
                        }
-
-                       Group [] result = new Group [ngroups];
+                       while (res == -1);
+                       Group [] result = new Group [res];
                        for (int i = 0; i < res; i++) 
                                result [i] = Syscall.getgrgid (groups [i]);
                        return result;