Files
runc/libcontainer/utils/utils_unix.go
Kir Kolyshkin d8da00355e *: add go-1.17+ go:build tags
Go 1.17 introduce this new (and better) way to specify build tags.
For more info, see https://golang.org/design/draft-gobuild.

As a way to seamlessly switch from old to new build tags, gofmt (and
gopls) from go 1.17 adds the new tags along with the old ones.

Later, when go < 1.17 is no longer supported, the old build tags
can be removed.

Now, as I started to use latest gopls (v0.7.1), it adds these tags
while I edit. Rather than to randomly add new build tags, I guess
it is better to do it once for all files.

Mind that previous commits removed some tags that were useless,
so this one only touches packages that can at least be built
on non-linux.

Brought to you by

        go1.17 fmt ./...

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2021-08-30 20:58:22 -07:00

70 lines
1.7 KiB
Go

//go:build !windows
// +build !windows
package utils
import (
"fmt"
"os"
"strconv"
"golang.org/x/sys/unix"
)
// EnsureProcHandle returns whether or not the given file handle is on procfs.
func EnsureProcHandle(fh *os.File) error {
var buf unix.Statfs_t
if err := unix.Fstatfs(int(fh.Fd()), &buf); err != nil {
return fmt.Errorf("ensure %s is on procfs: %w", fh.Name(), err)
}
if buf.Type != unix.PROC_SUPER_MAGIC {
return fmt.Errorf("%s is not on procfs", fh.Name())
}
return nil
}
// CloseExecFrom applies O_CLOEXEC to all file descriptors currently open for
// the process (except for those below the given fd value).
func CloseExecFrom(minFd int) error {
fdDir, err := os.Open("/proc/self/fd")
if err != nil {
return err
}
defer fdDir.Close()
if err := EnsureProcHandle(fdDir); err != nil {
return err
}
fdList, err := fdDir.Readdirnames(-1)
if err != nil {
return err
}
for _, fdStr := range fdList {
fd, err := strconv.Atoi(fdStr)
// Ignore non-numeric file names.
if err != nil {
continue
}
// Ignore descriptors lower than our specified minimum.
if fd < minFd {
continue
}
// Intentionally ignore errors from unix.CloseOnExec -- the cases where
// this might fail are basically file descriptors that have already
// been closed (including and especially the one that was created when
// ioutil.ReadDir did the "opendir" syscall).
unix.CloseOnExec(fd)
}
return nil
}
// NewSockPair returns a new unix socket pair
func NewSockPair(name string) (parent *os.File, child *os.File, err error) {
fds, err := unix.Socketpair(unix.AF_LOCAL, unix.SOCK_STREAM|unix.SOCK_CLOEXEC, 0)
if err != nil {
return nil, nil, err
}
return os.NewFile(uintptr(fds[1]), name+"-p"), os.NewFile(uintptr(fds[0]), name+"-c"), nil
}