feat: make probe always open blockdevices in readonly mode

Fixes: #44 Signed-off-by: Artem Chernyshev <[email protected]>
siderolabs · Sep 22, 2021 · a9cf3be · a9cf3be
1 parent d981156
commit a9cf3be
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Showing 3 changed files with 19 additions and 2 deletions.
diff --git a/blockdevice/blockdevice_linux.go b/blockdevice/blockdevice_linux.go
@@ -49,7 +49,7 @@ func Open(devname string, setters ...Option) (bd *BlockDevice, err error) {
 
 	var f *os.File
 
-	if f, err = os.OpenFile(devname, os.O_RDWR|unix.O_CLOEXEC, os.ModeDevice); err != nil {
+	if f, err = os.OpenFile(devname, opts.Mode, os.ModeDevice); err != nil {
 		return nil, err
 	}
 

diff --git a/blockdevice/options.go b/blockdevice/options.go
@@ -4,10 +4,17 @@
 
 package blockdevice
 
+import (
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
 // Options is the functional options struct.
 type Options struct {
 	CreateGPT     bool
 	ExclusiveLock bool
+	Mode          int
 }
 
 // Option is the functional option func.
@@ -27,10 +34,18 @@ func WithExclusiveLock(o bool) Option {
 	}
 }
 
+// WithMode opens blockdevice in a specific mode.
+func WithMode(value int) Option {
+	return func(args *Options) {
+		args.Mode = value
+	}
+}
+
 // NewDefaultOptions initializes a Options struct with default values.
 func NewDefaultOptions(setters ...Option) *Options {
 	opts := &Options{
 		CreateGPT: false,
+		Mode:      os.O_RDWR | unix.O_CLOEXEC,
 	}
 
 	for _, setter := range setters {

diff --git a/blockdevice/probe/probe.go b/blockdevice/probe/probe.go
@@ -11,6 +11,8 @@ import (
 	"os"
 	"path/filepath"
 
+	"golang.org/x/sys/unix"
+
 	"github.com/talos-systems/go-blockdevice/blockdevice"
 	"github.com/talos-systems/go-blockdevice/blockdevice/filesystem"
 	"github.com/talos-systems/go-blockdevice/blockdevice/filesystem/iso9660"
@@ -149,7 +151,7 @@ func probe(devpath string) (devpaths []string) {
 	// Start by opening the block device.
 	// If a partition table was not found, it is still possible that a
 	// file system exists without a partition table.
-	bd, err := blockdevice.Open(devpath)
+	bd, err := blockdevice.Open(devpath, blockdevice.WithMode(os.O_RDONLY|unix.O_CLOEXEC))
 	if err != nil {
 		//nolint: errcheck
 		if sb, _ := filesystem.Probe(devpath); sb != nil {