From a5543cc0d423cfaa62c39afe711d26c30725597c Mon Sep 17 00:00:00 2001
From: Tobias Nygren <tnn+github@nygren.pp.se>
Date: Sun, 22 Sep 2024 19:51:29 +0200
Subject: [PATCH] collector: add NetBSD support for filesystem (#3082)

Signed-off-by: Tobias Nygren <tnn@NetBSD.org>
---
 collector/filesystem_common.go |   4 +-
 collector/filesystem_netbsd.go | 132 +++++++++++++++++++++++++++++++++
 2 files changed, 134 insertions(+), 2 deletions(-)
 create mode 100644 collector/filesystem_netbsd.go

diff --git a/collector/filesystem_common.go b/collector/filesystem_common.go
index ee61aba8ec..b3b991d3a4 100644
--- a/collector/filesystem_common.go
+++ b/collector/filesystem_common.go
@@ -11,9 +11,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build !nofilesystem && (linux || freebsd || openbsd || darwin || dragonfly)
+//go:build !nofilesystem && (linux || freebsd || netbsd || openbsd || darwin || dragonfly)
 // +build !nofilesystem
-// +build linux freebsd openbsd darwin dragonfly
+// +build linux freebsd netbsd openbsd darwin dragonfly
 
 package collector
 
diff --git a/collector/filesystem_netbsd.go b/collector/filesystem_netbsd.go
new file mode 100644
index 0000000000..3d67d3473f
--- /dev/null
+++ b/collector/filesystem_netbsd.go
@@ -0,0 +1,132 @@
+// Copyright 2024 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.
+
+//go:build !nofilesystem
+// +build !nofilesystem
+
+package collector
+
+import (
+	"fmt"
+	"github.com/go-kit/log/level"
+	"golang.org/x/sys/unix"
+	"syscall"
+	"unsafe"
+)
+
+const (
+	defMountPointsExcluded = "^/(dev)($|/)"
+	defFSTypesExcluded     = "^(kernfs|procfs|ptyfs|fdesc)$"
+	_VFS_NAMELEN           = 32
+	_VFS_MNAMELEN          = 1024
+)
+
+/*
+ * Go uses the NetBSD 9 ABI and thus syscall.SYS_GETVFSSTAT is compat_90_getvfsstat.
+ * We have to declare struct statvfs90 because it is not included in the unix package.
+ * See NetBSD/src/sys/compat/sys/statvfs.h.
+ */
+type statvfs90 struct {
+	F_flag   uint
+	F_bsize  uint
+	F_frsize uint
+	F_iosize uint
+
+	F_blocks uint64
+	F_bfree  uint64
+	F_bavail uint64
+	F_bresvd uint64
+
+	F_files  uint64
+	F_ffree  uint64
+	F_favail uint64
+	F_fresvd uint64
+
+	F_syncreads  uint64
+	F_syncwrites uint64
+
+	F_asyncreads  uint64
+	F_asyncwrites uint64
+
+	F_fsidx   [2]uint32
+	F_fsid    uint32
+	F_namemax uint
+	F_owner   uint32
+	F_spare   [4]uint32
+
+	F_fstypename  [_VFS_NAMELEN]byte
+	F_mntonname   [_VFS_MNAMELEN]byte
+	F_mntfromname [_VFS_MNAMELEN]byte
+
+	cgo_pad [4]byte
+}
+
+func (c *filesystemCollector) GetStats() (stats []filesystemStats, err error) {
+	var mnt []statvfs90
+	if syscall.SYS_GETVFSSTAT != 356 /* compat_90_getvfsstat */ {
+		/*
+		 * Catch if golang ever updates to newer ABI and bail.
+		 */
+		return nil, fmt.Errorf("getvfsstat: ABI mismatch")
+	}
+	for {
+		r1, _, errno := syscall.Syscall(syscall.SYS_GETVFSSTAT, uintptr(0), 0, unix.ST_NOWAIT)
+		if errno != 0 {
+			return nil, fmt.Errorf("getvfsstat: %s", string(errno))
+		}
+		mnt = make([]statvfs90, r1, r1)
+		r2, _, errno := syscall.Syscall(syscall.SYS_GETVFSSTAT, uintptr(unsafe.Pointer(&mnt[0])), unsafe.Sizeof(mnt[0])*r1, unix.ST_NOWAIT /* ST_NOWAIT */)
+		if errno != 0 {
+			return nil, fmt.Errorf("getvfsstat: %s", string(errno))
+		}
+		if r1 == r2 {
+			break
+		}
+	}
+
+	stats = []filesystemStats{}
+	for _, v := range mnt {
+		mountpoint := unix.ByteSliceToString(v.F_mntonname[:])
+		if c.excludedMountPointsPattern.MatchString(mountpoint) {
+			level.Debug(c.logger).Log("msg", "Ignoring mount point", "mountpoint", mountpoint)
+			continue
+		}
+
+		device := unix.ByteSliceToString(v.F_mntfromname[:])
+		fstype := unix.ByteSliceToString(v.F_fstypename[:])
+		if c.excludedFSTypesPattern.MatchString(fstype) {
+			level.Debug(c.logger).Log("msg", "Ignoring fs type", "type", fstype)
+			continue
+		}
+
+		var ro float64
+		if (v.F_flag & unix.MNT_RDONLY) != 0 {
+			ro = 1
+		}
+
+		stats = append(stats, filesystemStats{
+			labels: filesystemLabels{
+				device:     device,
+				mountPoint: mountpoint,
+				fsType:     fstype,
+			},
+			size:      float64(v.F_blocks) * float64(v.F_bsize),
+			free:      float64(v.F_bfree) * float64(v.F_bsize),
+			avail:     float64(v.F_bavail) * float64(v.F_bsize),
+			files:     float64(v.F_files),
+			filesFree: float64(v.F_ffree),
+			ro:        ro,
+		})
+	}
+	return stats, nil
+}