nsenter package registers a special init constructor that is called before
the Go runtime has a chance to boot. This provides us the ability to
existing namespaces and avoid the issues that the Go runtime has with multiple
threads. This constructor will be called if this package is registered,
imported, in your go application.
nsenter package will
import "C" and it uses cgo
package. In cgo, if the import of "C" is immediately preceded by a comment, that comment,
called the preamble, is used as a header when compiling the C parts of the package.
So every time we import package
nsenter, the C code function
nsexec() would be
called. And package
nsenter is now only imported in Docker execdriver, so every time
before we call
execdriver.Exec(), that C code would run.
nsexec() will first check the environment variable
which will give the process of the container that should be joined. Namespaces fd will
be found from
/proc/[pid]/ns and set by
And then get the pipe number from
_LIBCONTAINER_INITPIPE, error message could
be transfered through it. If tty is added,
have value and start a console for output.
nsexec() will clone a child process , exit the parent process and let
the Go runtime take over.
There is no documentation for this package.