From 087b953dc5d179f2515dac99c350e2bdbfa1cda7 Mon Sep 17 00:00:00 2001
From: Aleksa Sarai <asarai@suse.de>
Date: Mon, 14 Mar 2016 17:45:12 +1100
Subject: [PATCH] libcontainer: cgroups: deal with unlimited case for pids.max

Make sure we don't error out collecting statistics for cases where
pids.max == "max". In that case, we can use a limit of 0 which means
"unlimited".

In addition, change the name of the stats attribute (Max) to mirror the
name of the resources attribute in the spec (Limit) so that it's
consistent internally.

Signed-off-by: Aleksa Sarai <asarai@suse.de>
---
 libcontainer/cgroups/fs/pids.go | 14 ++++++++++++--
 libcontainer/cgroups/stats.go   |  2 +-
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/libcontainer/cgroups/fs/pids.go b/libcontainer/cgroups/fs/pids.go
index 8f187a59e..f1e372055 100644
--- a/libcontainer/cgroups/fs/pids.go
+++ b/libcontainer/cgroups/fs/pids.go
@@ -4,6 +4,7 @@ package fs
 
 import (
 	"fmt"
+	"path/filepath"
 	"strconv"
 
 	"github.com/opencontainers/runc/libcontainer/cgroups"
@@ -52,12 +53,21 @@ func (s *PidsGroup) GetStats(path string, stats *cgroups.Stats) error {
 		return fmt.Errorf("failed to parse pids.current - %s", err)
 	}
 
-	max, err := getCgroupParamUint(path, "pids.max")
+	maxString, err := getCgroupParamString(path, "pids.max")
 	if err != nil {
 		return fmt.Errorf("failed to parse pids.max - %s", err)
 	}
 
+	// Default if pids.max == "max" is 0 -- which represents "no limit".
+	var max uint64
+	if maxString != "max" {
+		max, err = parseUint(maxString, 10, 64)
+		if err != nil {
+			return fmt.Errorf("failed to parse pids.max - unable to parse %q as a uint from Cgroup file %q", maxString, filepath.Join(path, "pids.max"))
+		}
+	}
+
 	stats.PidsStats.Current = current
-	stats.PidsStats.Max = max
+	stats.PidsStats.Limit = max
 	return nil
 }
diff --git a/libcontainer/cgroups/stats.go b/libcontainer/cgroups/stats.go
index 7eba44148..1b280fc71 100644
--- a/libcontainer/cgroups/stats.go
+++ b/libcontainer/cgroups/stats.go
@@ -55,7 +55,7 @@ type PidsStats struct {
 	// number of pids in the cgroup
 	Current uint64 `json:"current,omitempty"`
 	// active pids hard limit
-	Max uint64 `json:"max,omitempty"`
+	Limit uint64 `json:"limit,omitempty"`
 }
 
 type BlkioStatEntry struct {