Files
runc/libcontainer/system/rlimit_linux_go122.go
Kir Kolyshkin 584afc6756 libct/system: ClearRlimitNofileCache for go 1.23
Go 1.23 tightens access to internal symbols, and even puts runc into
"hall of shame" for using an internal symbol (recently added by commit
da68c8e3). So, while not impossible, it becomes harder to access those
internal symbols, and it is a bad idea in general.

Since Go 1.23 includes https://go.dev/cl/588076, we can clean the
internal rlimit cache by setting the RLIMIT_NOFILE for ourselves,
essentially disabling the rlimit cache.

Once Go 1.22 is no longer supported, we will remove the go:linkname hack.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2024-06-01 13:02:29 -07:00

28 lines
1022 B
Go

//go:build !go1.23
// TODO: remove this file once go 1.22 is no longer supported.
package system
import (
"sync/atomic"
"syscall"
_ "unsafe" // Needed for go:linkname to work.
)
//go:linkname syscallOrigRlimitNofile syscall.origRlimitNofile
var syscallOrigRlimitNofile atomic.Pointer[syscall.Rlimit]
// ClearRlimitNofileCache clears go runtime's nofile rlimit cache.
// The argument is process RLIMIT_NOFILE values.
func ClearRlimitNofileCache(_ *syscall.Rlimit) {
// As reported in issue #4195, the new version of go runtime(since 1.19)
// will cache rlimit-nofile. Before executing execve, the rlimit-nofile
// of the process will be restored with the cache. In runc, this will
// cause the rlimit-nofile setting by the parent process for the container
// to become invalid. It can be solved by clearing this cache. But
// unfortunately, go stdlib doesn't provide such function, so we need to
// link to the private var `origRlimitNofile` in package syscall to hack.
syscallOrigRlimitNofile.Store(nil)
}