Fix data types for ignored stat fields #401

Some ignored fields in the /proc/[pid]/stat file may have values that are bigger than the max value of the current Go type that is used for the ignored variable. That leads to issues in runtime on some systems that use the maximum possible values for the related fields.

See for details:
* https://man7.org/linux/man-pages/man5/proc.5.html
* https://man7.org/linux/man-pages/man3/scanf.3.html

Signed-off-by: Vyacheslav Kulakov <kulakov.home@gmail.com>

proc_stat.go

@@ -128,7 +128,8 @@ func (p Proc) Stat() (ProcStat, error) {
 	}
 
 	var (
-		ignore int
+		ignoreInt64  int64
+		ignoreUint64 uint64
 
 		s = ProcStat{PID: p.PID, proc: p.fs}
 		l = bytes.Index(data, []byte("("))
@@ -160,25 +161,25 @@ func (p Proc) Stat() (ProcStat, error) {
 		&s.Priority,
 		&s.Nice,
 		&s.NumThreads,
-		&ignore,
+		&ignoreInt64,
 		&s.Starttime,
 		&s.VSize,
 		&s.RSS,
 		&s.RSSLimit,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
-		&ignore,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreUint64,
+		&ignoreInt64,
+		&ignoreInt64,
 		&s.RTPriority,
 		&s.Policy,
 		&s.DelayAcctBlkIOTicks,

proc_stat_test.go

@@ -76,6 +76,18 @@ func TestProcStat(t *testing.T) {
 	}
 }
 
+func TestProcStatIgnored(t *testing.T) {
+	p, err := getProcFixtures(t).Proc(26232)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = p.Stat()
+	if err != nil {
+		t.Errorf("want not error, have %s", err)
+	}
+}
+
 func TestProcStatComm(t *testing.T) {
 	s1, err := testProcStat(26231)
 	if err != nil {