From e416d6dbc784c46140d50cfe49b7cc4aa8867d06 Mon Sep 17 00:00:00 2001
From: Timur Alperovich <timur.alperovich@databricks.com>
Date: Mon, 17 Jun 2024 10:55:08 -0700
Subject: [PATCH] Fix parsing NSpids field in /proc/{PID}/status

The NSpids field uses a tab (\t) to separate the list of PIDs. The
procfs parser should split on \t, rather than space. This was not caught
because the test fixtures themselves used the space character.

The patch updates the parser, the fixtures, and adds an explicit test
for NSpids.

Signed-off-by: Timur Alperovich <timur.alperovich@databricks.com>
---
 proc_status.go         | 18 +++++++++++-------
 proc_status_test.go    | 16 ++++++++++++++++
 testdata/fixtures.ttar |  8 ++++----
 3 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/proc_status.go b/proc_status.go
index a055197c..dd8aa568 100644
--- a/proc_status.go
+++ b/proc_status.go
@@ -146,7 +146,11 @@ func (s *ProcStatus) fillStatus(k string, vString string, vUint uint64, vUintByt
 			}
 		}
 	case "NSpid":
-		s.NSpids = calcNSPidsList(vString)
+		nspids, err := calcNSPidsList(vString)
+		if err != nil {
+			return err
+		}
+		s.NSpids = nspids
 	case "VmPeak":
 		s.VmPeak = vUintBytes
 	case "VmSize":
@@ -222,17 +226,17 @@ func calcCpusAllowedList(cpuString string) []uint64 {
 	return g
 }
 
-func calcNSPidsList(nspidsString string) []uint64 {
-	s := strings.Split(nspidsString, " ")
+func calcNSPidsList(nspidsString string) ([]uint64, error) {
+	s := strings.Split(nspidsString, "\t")
 	var nspids []uint64
 
 	for _, nspid := range s {
-		nspid, _ := strconv.ParseUint(nspid, 10, 64)
-		if nspid == 0 {
-			continue
+		nspid, err := strconv.ParseUint(nspid, 10, 64)
+		if err != nil {
+			return nil, err
 		}
 		nspids = append(nspids, nspid)
 	}
 
-	return nspids
+	return nspids, nil
 }
diff --git a/proc_status_test.go b/proc_status_test.go
index 9644bf01..e41d36ba 100644
--- a/proc_status_test.go
+++ b/proc_status_test.go
@@ -139,3 +139,19 @@ func TestCpusAllowedList(t *testing.T) {
 		t.Errorf("want CpusAllowedList %v, have %v", want, have)
 	}
 }
+
+func TestNsPids(t *testing.T) {
+	p, err := getProcFixtures(t).Proc(26235)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	s, err := p.NewStatus()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if want, have := []uint64{26235, 1}, s.NSpids; !reflect.DeepEqual(want, have) {
+		t.Errorf("want NsPids %v, have %v", want, have)
+	}
+}
diff --git a/testdata/fixtures.ttar b/testdata/fixtures.ttar
index 4bc508b8..f2bd5e56 100644
--- a/testdata/fixtures.ttar
+++ b/testdata/fixtures.ttar
@@ -818,10 +818,10 @@ Uid:	0	0	0	0
 Gid:	0	0	0	0
 FDSize: 64
 Groups:
-NStgid: 26235   1
-NSpid:  26235   1
-NSpgid: 26235   1
-NSsid:  26235   1
+NStgid: 26235	1
+NSpid:  26235	1
+NSpgid: 26235	1
+NSsid:  26235	1
 VmPeak:   758200 kB
 VmSize:   758200 kB
 VmLck:         0 kB