golangci-lint v1.54.2 comes with errorlint v1.4.4, which contains
the fix [1] whitelisting all errno comparisons for errors coming from
x/sys/unix.
Thus, these annotations are no longer necessary. Hooray!
[1] https://github.com/polyfloyd/go-errorlint/pull/47
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
opencontainers/runc issue 3026 describes a scenario in which OpenFile
failed to open a legitimate existing cgroupfs file. Added debug
(similar to what this commit does) shown that cgroupFd is no longer
opened to "/sys/fs/cgroup", but to "/" (it's not clear what caused it,
and the source code is not available, but they might be using the same
process on the both sides of the container/chroot/pivot_root/mntns
boundary, or remounting /sys/fs/cgroup).
Consider such use incorrect, but give a helpful hint as two what is
going on by wrapping the error in a more useful message.
NB: this can potentially be fixed by reopening the cgroupFd once we
detected that it's screwed, and retrying openat2. Alas I do not have
a test case for this, so left this as a TODO suggestion.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Fix reading cgroup files from the top cgroup directory, i.e.
/sys/fs/cgroup.
The code was working for for any subdirectory of /sys/fs/cgroup, but
for dir="/sys/fs/cgroup" a fallback (open and fstatfs) was used, because
of the way the function worked with the dir argument.
Fix those cases, and add unit tests to make sure they work. While at it,
make the rules for dir and name components more relaxed, and add test
cases for this, too.
While at it, improve OpenFile documentation, and remove a duplicated
doc comment for openFile.
Without these fixes, the unit test fails the following cases:
file_test.go:67: case {path:/sys/fs/cgroup name:cgroup.controllers}: fallback
file_test.go:67: case {path:/sys/fs/cgroup/ name:cgroup.controllers}: openat2 /sys/fs/cgroup//cgroup.controllers: invalid cross-device link
file_test.go:67: case {path:/sys/fs/cgroup/ name:/cgroup.controllers}: openat2 /sys/fs/cgroup///cgroup.controllers: invalid cross-device link
file_test.go:67: case {path:/ name:/sys/fs/cgroup/cgroup.controllers}: fallback
file_test.go:67: case {path:/ name:sys/fs/cgroup/cgroup.controllers}: fallback
file_test.go:67: case {path:/sys/fs/cgroup/cgroup.controllers name:}: openat2 /sys/fs/cgroup/cgroup.controllers/: not a directory
Here "fallback" means openat2-based implementation fails, and the fallback code
is used (and works).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Errors from unix.* are always bare and thus can be used directly.
Add //nolint:errorlint annotation to ignore errors such as these:
libcontainer/system/xattrs_linux.go:18:7: comparing with == will fail on wrapped errors. Use errors.Is to check for a specific error (errorlint)
case errno == unix.ERANGE:
^
libcontainer/container_linux.go:1259:9: comparing with != will fail on wrapped errors. Use errors.Is to check for a specific error (errorlint)
if e != unix.EINVAL {
^
libcontainer/rootfs_linux.go:919:7: comparing with != will fail on wrapped errors. Use errors.Is to check for a specific error (errorlint)
if err != unix.EINVAL && err != unix.EPERM {
^
libcontainer/rootfs_linux.go:1002:4: switch on an error will fail on wrapped errors. Use errors.Is to check for specific errors (errorlint)
switch err {
^
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This is a better place as cgroups itself is using these.
Should help with moving more stuff common in between fs and fs2 to
fscommon.
Looks big, but this is just moving the code around:
fscommon/{fscommon,open}.go -> cgroups/file.go
fscommon/fscommon_test.go -> cgroups/file_test.go
and fixes for TestMode moved to a different package.
There's no functional change.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Kir Kolyshkin