podman cgroup enhancement

currently, setting any sort of resource limit in a pod does nothing. With the newly refactored creation process in c/common, podman ca now set resources at a pod level
meaning that resource related flags can now be exposed to podman pod create.

cgroupfs and systemd are both supported with varying completion. cgroupfs is a much simpler process and one that is virtually complete for all resource types, the flags now just need to be added. systemd on the other hand
has to be handeled via the dbus api meaning that the limits need to be passed as recognized properties to systemd. The properties added so far are the ones that podman pod create supports as well as `cpuset-mems` as this will
be the next flag I work on.

Signed-off-by: Charlie Doern <cdoern@redhat.com>

1 files changed, 72 insertions, 0 deletions

diff --git a/vendor/github.com/opencontainers/runc/libcontainer/cgroups/fs2/pids.go b/vendor/github.com/opencontainers/runc/libcontainer/cgroups/fs2/pids.go
new file mode 100644
index 000000000..c8c4a3658
--- /dev/null
+++ b/vendor/github.com/opencontainers/runc/libcontainer/cgroups/fs2/pids.go
@@ -0,0 +1,72 @@
+package fs2
+
+import (
+	"errors"
+	"math"
+	"os"
+	"strings"
+
+	"golang.org/x/sys/unix"
+
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+	"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
+	"github.com/opencontainers/runc/libcontainer/configs"
+)
+
+func isPidsSet(r *configs.Resources) bool {
+	return r.PidsLimit != 0
+}
+
+func setPids(dirPath string, r *configs.Resources) error {
+	if !isPidsSet(r) {
+		return nil
+	}
+	if val := numToStr(r.PidsLimit); val != "" {
+		if err := cgroups.WriteFile(dirPath, "pids.max", val); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func statPidsFromCgroupProcs(dirPath string, stats *cgroups.Stats) error {
+	// if the controller is not enabled, let's read PIDS from cgroups.procs
+	// (or threads if cgroup.threads is enabled)
+	contents, err := cgroups.ReadFile(dirPath, "cgroup.procs")
+	if errors.Is(err, unix.ENOTSUP) {
+		contents, err = cgroups.ReadFile(dirPath, "cgroup.threads")
+	}
+	if err != nil {
+		return err
+	}
+	pids := strings.Count(contents, "\n")
+	stats.PidsStats.Current = uint64(pids)
+	stats.PidsStats.Limit = 0
+	return nil
+}
+
+func statPids(dirPath string, stats *cgroups.Stats) error {
+	current, err := fscommon.GetCgroupParamUint(dirPath, "pids.current")
+	if err != nil {
+		if os.IsNotExist(err) {
+			return statPidsFromCgroupProcs(dirPath, stats)
+		}
+		return err
+	}
+
+	max, err := fscommon.GetCgroupParamUint(dirPath, "pids.max")
+	if err != nil {
+		return err
+	}
+	// If no limit is set, read from pids.max returns "max", which is
+	// converted to MaxUint64 by GetCgroupParamUint. Historically, we
+	// represent "no limit" for pids as 0, thus this conversion.
+	if max == math.MaxUint64 {
+		max = 0
+	}
+
+	stats.PidsStats.Current = current
+	stats.PidsStats.Limit = max
+	return nil
+}