19 files changed, 120 insertions, 8 deletions

diff --git a/collector/drbd_linux.go b/collector/drbd_linux.go
index 6815c5f..4beb31d 100644
--- a/collector/drbd_linux.go
+++ b/collector/drbd_linux.go
@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nodrbd
+
 package collector
 
 import (
diff --git a/collector/filesystem_freebsd.go b/collector/filesystem_freebsd.go
index f37029e..1d377b1 100644
--- a/collector/filesystem_freebsd.go
+++ b/collector/filesystem_freebsd.go
@@ -40,14 +40,14 @@ func (c *filesystemCollector) GetStats() ([]filesystemStats, error) {
         }
         stats := []filesystemStats{}
         for _, fs := range buf {
-                mountpoint := string(fs.Mntonname[:])
+                mountpoint := bytesToString(fs.Mntonname[:])
                 if c.ignoredMountPointsPattern.MatchString(mountpoint) {
                         level.Debug(c.logger).Log("msg", "Ignoring mount point", "mountpoint", mountpoint)
                         continue
                 }
 
-                device := string(fs.Mntfromname[:])
-                fstype := string(fs.Fstypename[:])
+                device := bytesToString(fs.Mntfromname[:])
+                fstype := bytesToString(fs.Fstypename[:])
                 if c.ignoredFSTypesPattern.MatchString(fstype) {
                         level.Debug(c.logger).Log("msg", "Ignoring fs type", "type", fstype)
                         continue
diff --git a/collector/filesystem_linux_test.go b/collector/filesystem_linux_test.go
index 973cd14..e401779 100644
--- a/collector/filesystem_linux_test.go
+++ b/collector/filesystem_linux_test.go
@@ -11,8 +11,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build !nofilesystem
-
 package collector
 
 import (
diff --git a/collector/fixtures/sys.ttar b/collector/fixtures/sys.ttar
index a4550a5..3e52c60 100644
--- a/collector/fixtures/sys.ttar
+++ b/collector/fixtures/sys.ttar
@@ -1756,6 +1756,17 @@ Lines: 1
 0
 Mode: 644
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: sys/devices/pci0000:00/0000:00:0d.0/ata4/host3/target3:0:0/3:0:0:0/block/sdb/bcache/writeback_rate_debug
+Lines: 7
+rate:           1.1M/sec
+dirty:          20.4G
+target:         20.4G
+proportional:   427.5k
+integral:       790.0k
+change:         321.5k/sec
+next io:        17ms
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Directory: sys/devices/pci0000:00/0000:00:0d.0/ata5
 Mode: 755
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/collector/helper.go b/collector/helper.go
index 2bf461e..df5cd26 100644
--- a/collector/helper.go
+++ b/collector/helper.go
@@ -14,6 +14,7 @@
 package collector
 
 import (
+        "bytes"
         "io/ioutil"
         "strconv"
         "strings"
@@ -30,3 +31,16 @@ func readUintFromFile(path string) (uint64, error) {
         }
         return value, nil
 }
+
+// Take a []byte{} and return a string based on null termination.
+// This is useful for situations where the OS has returned a null terminated
+// string to use.
+// If this function happens to receive a byteArray that contains no nulls, we
+// simply convert the array to a string with no bounding.
+func bytesToString(byteArray []byte) string {
+        n := bytes.IndexByte(byteArray, 0)
+        if n < 0 {
+                return string(byteArray)
+        }
+        return string(byteArray[:n])
+}
diff --git a/collector/helper_test.go b/collector/helper_test.go
new file mode 100644
index 0000000..0424d48
--- /dev/null
+++ b/collector/helper_test.go
@@ -0,0 +1,63 @@
+// Copyright 2020 The Prometheus 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 collector
+
+import (
+        "testing"
+)
+
+func TestBytesToString(t *testing.T) {
+        tests := []struct {
+                name     string
+                b        []byte
+                expected string
+        }{
+                {
+                        "Single null byte",
+                        []byte{0},
+                        "",
+                },
+                {
+                        "Empty byte array",
+                        []byte{},
+                        "",
+                },
+                {
+                        "Not null terminated",
+                        []byte{65, 66, 67},
+                        "ABC",
+                },
+                {
+                        "Null randomly in array",
+                        []byte{65, 66, 67, 0, 65, 0, 65},
+                        "ABC",
+                },
+                {
+                        "Array starts with null and contains other valid bytes",
+                        []byte{0, 65, 66, 67, 0},
+                        "",
+                },
+        }
+
+        for _, tt := range tests {
+                name := tt.name
+                b := tt.b
+                result := bytesToString(b)
+                expected := tt.expected
+
+                if result != expected {
+                        t.Errorf("bytesToString(%#v): Name: %s, expected %#v, got %#v)", b, name, expected, result)
+                }
+        }
+}
diff --git a/collector/kvm_bsd.go b/collector/kvm_bsd.go
index b4e95e6..8798736 100644
--- a/collector/kvm_bsd.go
+++ b/collector/kvm_bsd.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build !nomeminfo
+// +build !nokvm
 // +build freebsd dragonfly
 
 package collector
diff --git a/collector/mountstats_linux.go b/collector/mountstats_linux.go
index 3fa1597..4102067 100644
--- a/collector/mountstats_linux.go
+++ b/collector/mountstats_linux.go
@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nomountstats
+
 package collector
 
 import (
diff --git a/collector/nfs_linux.go b/collector/nfs_linux.go
index 55f9e19..a540bb3 100644
--- a/collector/nfs_linux.go
+++ b/collector/nfs_linux.go
@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nonfs
+
 package collector
 
 import (
diff --git a/collector/nfsd_linux.go b/collector/nfsd_linux.go
index b6f2f8e..8cb1e05 100644
--- a/collector/nfsd_linux.go
+++ b/collector/nfsd_linux.go
@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nonfsd
+
 package collector
 
 import (
diff --git a/collector/perf_linux.go b/collector/perf_linux.go
index e452754..3a2f739 100644
--- a/collector/perf_linux.go
+++ b/collector/perf_linux.go
@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !noperf
+
 package collector
 
 import (
diff --git a/collector/powersupplyclass.go b/collector/powersupplyclass.go
index 988b0ee..309b08c 100644
--- a/collector/powersupplyclass.go
+++ b/collector/powersupplyclass.go
@@ -17,7 +17,9 @@
 package collector
 
 import (
+        "errors"
         "fmt"
+        "os"
         "regexp"
 
         "github.com/go-kit/kit/log"
@@ -54,6 +56,9 @@ func NewPowerSupplyClassCollector(logger log.Logger) (Collector, error) {
 func (c *powerSupplyClassCollector) Update(ch chan<- prometheus.Metric) error {
         powerSupplyClass, err := getPowerSupplyClassInfo(c.ignoredPattern)
         if err != nil {
+                if errors.Is(err, os.ErrNotExist) {
+                        return ErrNoData
+                }
                 return fmt.Errorf("could not get power_supply class info: %s", err)
         }
         for _, powerSupply := range powerSupplyClass {
@@ -184,7 +189,7 @@ func getPowerSupplyClassInfo(ignore *regexp.Regexp) (sysfs.PowerSupplyClass, err
         powerSupplyClass, err := fs.PowerSupplyClass()
 
         if err != nil {
-                return powerSupplyClass, fmt.Errorf("error obtaining power_supply class info: %s", err)
+                return powerSupplyClass, fmt.Errorf("error obtaining power_supply class info: %w", err)
         }
 
         for device := range powerSupplyClass {
diff --git a/collector/schedstat_linux.go b/collector/schedstat_linux.go
index d2f04f6..9e5b744 100644
--- a/collector/schedstat_linux.go
+++ b/collector/schedstat_linux.go
@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !noshedstat
+
 package collector
 
 import (
diff --git a/collector/sysctl_bsd.go b/collector/sysctl_bsd.go
index 3038f41..a671bc2 100644
--- a/collector/sysctl_bsd.go
+++ b/collector/sysctl_bsd.go
@@ -12,7 +12,7 @@
 // limitations under the License.
 
 // +build freebsd dragonfly openbsd netbsd darwin
-// +build !nomeminfo
+// +build cgo
 
 package collector
 
diff --git a/collector/wifi_linux.go b/collector/wifi_linux.go
index 118e714..b4b3759 100644
--- a/collector/wifi_linux.go
+++ b/collector/wifi_linux.go
@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nowifi
+
 package collector
 
 import (
diff --git a/collector/xfs_linux.go b/collector/xfs_linux.go
index 77824c5..36dfff5 100644
--- a/collector/xfs_linux.go
+++ b/collector/xfs_linux.go
@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !noxfs
+
 package collector
 
 import (
diff --git a/collector/zfs_freebsd.go b/collector/zfs_freebsd.go
index a625bbc..92661e4 100644
--- a/collector/zfs_freebsd.go
+++ b/collector/zfs_freebsd.go
@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nozfs
+
 package collector
 
 import (
diff --git a/collector/zfs_linux.go b/collector/zfs_linux.go
index e2c9749..2449c26 100644
--- a/collector/zfs_linux.go
+++ b/collector/zfs_linux.go
@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nozfs
+
 package collector
 
 import (
diff --git a/collector/zfs_solaris.go b/collector/zfs_solaris.go
index bfda64f..1c0460c 100644
--- a/collector/zfs_solaris.go
+++ b/collector/zfs_solaris.go
@@ -12,6 +12,7 @@
 // limitations under the License.
 
 // +build solaris
+// +build !nozfs
 
 package collector