1 files changed, 42 insertions, 0 deletions
diff --git a/src/os/user/getgrouplist_unix.go b/src/os/user/getgrouplist_unix.go
new file mode 100644
index 0000000..9685414
--- /dev/null
+++ b/src/os/user/getgrouplist_unix.go
@@ -0,0 +1,42 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build dragonfly freebsd !android,linux netbsd openbsd
+// +build cgo,!osusergo
+
+package user
+
+/*
+#include <unistd.h>
+#include <sys/types.h>
+#include <grp.h>
+
+static int mygetgrouplist(const char* user, gid_t group, gid_t* groups, int* ngroups) {
+	return getgrouplist(user, group, groups, ngroups);
+}
+*/
+import "C"
+import (
+	"fmt"
+	"unsafe"
+)
+
+func getGroupList(name *C.char, userGID C.gid_t, gids *C.gid_t, n *C.int) C.int {
+	return C.mygetgrouplist(name, userGID, gids, n)
+}
+
+// groupRetry retries getGroupList with much larger size for n. The result is
+// stored in gids.
+func groupRetry(username string, name []byte, userGID C.gid_t, gids *[]C.gid_t, n *C.int) error {
+	// More than initial buffer, but now n contains the correct size.
+	if *n > maxGroups {
+		return fmt.Errorf("user: %q is a member of more than %d groups", username, maxGroups)
+	}
+	*gids = make([]C.gid_t, *n)
+	rv := getGroupList((*C.char)(unsafe.Pointer(&name[0])), userGID, &(*gids)[0], n)
+	if rv == -1 {
+		return fmt.Errorf("user: list groups for %s failed", username)
+	}
+	return nil
+}