d94a789d15
It says: The prefix path **must be absolute, have all symlinks resolved, and cleaned**. But those requirements are violated in lots of places. What happens when it is given a non-canonicalized path is that `mountinfo.GetMounts` will not find mounts. The trivial case is: ``` $ mkdir a && ln -s a b && mkdir b/c b/d && mount --bind b/c b/d && cat /proc/mounts | grep -- '[ab]/d' /dev/sdd3 /home/user/a/d ext4 rw,noatime,discard 0 0 ``` We asked to bind-mount b/c to b/d, but ended up with mount in a/d. So, mount table always contains canonicalized mount points, and it is an error to look for non-canonicalized paths in it. Signed-off-by: Marat Radchenko <marat@slonopotamus.org>
52 lines
1.3 KiB
Go
52 lines
1.3 KiB
Go
//go:build !windows
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/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package mount
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import (
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"fmt"
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"github.com/moby/sys/mountinfo"
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)
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// Lookup returns the mount info corresponds to the path.
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func Lookup(dir string) (Info, error) {
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resolvedDir, err := CanonicalizePath(dir)
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if err != nil {
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return Info{}, err
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}
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m, err := mountinfo.GetMounts(mountinfo.ParentsFilter(resolvedDir))
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if err != nil {
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return Info{}, fmt.Errorf("failed to find the mount info for %q: %w", resolvedDir, err)
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}
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if len(m) == 0 {
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return Info{}, fmt.Errorf("failed to find the mount info for %q", resolvedDir)
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}
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// find the longest matching mount point
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var idx, maxlen int
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for i := range m {
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if len(m[i].Mountpoint) > maxlen {
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maxlen = len(m[i].Mountpoint)
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idx = i
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}
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}
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return *m[idx], nil
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}
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