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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2018 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* 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, see <http://www.gnu.org/licenses/>.
*
*/
package osutil_test
import (
"os"
"path/filepath"
"syscall"
. "gopkg.in/check.v1"
"github.com/snapcore/snapd/osutil"
)
type sysSuite struct{}
var _ = Suite(&sysSuite{})
func (s *sysSuite) TestSymlinkatAndReadlinkat(c *C) {
// Create and open a temporary directory.
d := c.MkDir()
fd, err := syscall.Open(d, syscall.O_DIRECTORY, 0)
c.Assert(err, IsNil)
defer syscall.Close(fd)
// Create a symlink relative to the directory file descriptor.
err = osutil.Symlinkat("target", fd, "linkpath")
c.Assert(err, IsNil)
// Ensure that the created file is a symlink.
fname := filepath.Join(d, "linkpath")
fi, err := os.Lstat(fname)
c.Assert(err, IsNil)
c.Assert(fi.Name(), Equals, "linkpath")
c.Assert(fi.Mode()&os.ModeSymlink, Equals, os.ModeSymlink)
// Ensure that the symlink target is correct.
target, err := os.Readlink(fname)
c.Assert(err, IsNil)
c.Assert(target, Equals, "target")
// Use readlinkat with a buffer that fits only part of the target path.
buf := make([]byte, 2)
n, err := osutil.Readlinkat(fd, "linkpath", buf)
c.Assert(err, IsNil)
c.Assert(n, Equals, 2)
c.Assert(buf, DeepEquals, []byte{'t', 'a'})
// Use a buffer that fits all of the target path.
buf = make([]byte, 100)
n, err = osutil.Readlinkat(fd, "linkpath", buf)
c.Assert(err, IsNil)
c.Assert(n, Equals, len("target"))
c.Assert(buf[:n], DeepEquals, []byte{'t', 'a', 'r', 'g', 'e', 't'})
}
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