(below is a quote from my runc commit 6f82d4b)
TL;DR: check for IsExist(err) after a failed MkdirAll() is both
redundant and wrong -- so two reasons to remove it.
Quoting MkdirAll documentation:
> MkdirAll creates a directory named path, along with any necessary
> parents, and returns nil, or else returns an error. If path
> is already a directory, MkdirAll does nothing and returns nil.
This means two things:
1. If a directory to be created already exists, no error is
returned.
2. If the error returned is IsExist (EEXIST), it means there exists
a non-directory with the same name as MkdirAll need to use for
directory. Example: we want to MkdirAll("a/b"), but file "a"
(or "a/b") already exists, so MkdirAll fails.
The above is a theory, based on quoted documentation and my UNIX
knowledge.
3. In practice, though, current MkdirAll implementation [1] returns
ENOTDIR in most of cases described in #2, with the exception when
there is a race between MkdirAll and someone else creating the
last component of MkdirAll argument as a file. In this very case
MkdirAll() will indeed return EEXIST.
Because of #1, IsExist check after MkdirAll is not needed.
Because of #2 and #3, ignoring IsExist error is just plain wrong,
as directory we require is not created. It's cleaner to report
the error now.
Note this error is all over the tree, I guess due to copy-paste,
or trying to follow the same usage pattern as for Mkdir(),
or some not quite correct examples on the Internet.
[1] https://github.com/golang/go/blob/f9ed2f75/src/os/path.go
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Add details on kernel version, criu, snapshotters, and links to existing
sections for developers/criu details.
Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com>
We can't really use `dlopen()` from a statically built binary, so
let's disable this functionality if `static_build` tag is used
(which is sort of a de-facto standard way of doing it).
This eliminates the following warning:
🇩 bin/containerd
# github.com/containerd/containerd/cmd/containerd
/tmp/go-link-509179974/000004.o: In function `pluginOpen':
/usr/local/go/src/plugin/plugin_dlopen.go:19: warning: Using 'dlopen' in
statically linked applications requires at runtime the shared libraries
from the glibc version used for linking
[v2: add static build instructions to BUILDING.md]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This subreaper should always be turned on for containerd unless
explicitly needed for it to be off.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
