mount: add support for OpenBSD

Signed-off-by: Ivan Markin <sw@nogoegst.net>

mount/mountinfo_bsd.go

@@ -0,0 +1,63 @@
+// +build freebsd openbsd
+
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package mount
+
+/*
+#include <sys/param.h>
+#include <sys/ucred.h>
+#include <sys/mount.h>
+*/
+import "C"
+
+import (
+	"fmt"
+	"reflect"
+	"unsafe"
+)
+
+// Self retrieves a list of mounts for the current running process.
+func Self() ([]Info, error) {
+	var rawEntries *C.struct_statfs
+
+	count := int(C.getmntinfo(&rawEntries, C.MNT_WAIT))
+	if count == 0 {
+		return nil, fmt.Errorf("Failed to call getmntinfo")
+	}
+
+	var entries []C.struct_statfs
+	header := (*reflect.SliceHeader)(unsafe.Pointer(&entries))
+	header.Cap = count
+	header.Len = count
+	header.Data = uintptr(unsafe.Pointer(rawEntries))
+
+	var out []Info
+	for _, entry := range entries {
+		var mountinfo Info
+		mountinfo.Mountpoint = C.GoString(&entry.f_mntonname[0])
+		mountinfo.Source = C.GoString(&entry.f_mntfromname[0])
+		mountinfo.FSType = C.GoString(&entry.f_fstypename[0])
+		out = append(out, mountinfo)
+	}
+	return out, nil
+}
+
+// PID collects the mounts for a specific process ID.
+func PID(pid int) ([]Info, error) {
+	return nil, fmt.Errorf("mountinfo.PID is not implemented on freebsd")
+}