feat: provide an option to overwrite some args in AppendAll

See siderolabs/talos#3011

Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>

procfs/cmdline.go

@@ -198,10 +198,47 @@ func (c *Cmdline) Append(k, v string) {
 	insert(&c.Parameters, k, v)
 }
 
+// AppendAllOptions provides additional options for AppendAll.
+type AppendAllOptions struct {
+	OverwriteArgs []string
+}
+
+// AppendAllOption is a functional option for AppendAll.
+type AppendAllOption func(*AppendAllOptions)
+
+// WithOverwriteArgs specifies kernel arguments which should be overwritten with AppendAll.
+func WithOverwriteArgs(args ...string) AppendAllOption {
+	return func(opts *AppendAllOptions) {
+		opts.OverwriteArgs = append(opts.OverwriteArgs, args...)
+	}
+}
+
 // AppendAll appends a set of kernel parameters.
-func (c *Cmdline) AppendAll(args []string) error {
+func (c *Cmdline) AppendAll(args []string, opts ...AppendAllOption) error {
+	var options AppendAllOptions
+
+	for _, opt := range opts {
+		opt(&options)
+	}
+
 	parameters := parse(strings.Join(args, " "))
 	for _, p := range parameters {
+		overwrite := false
+
+		for _, key := range options.OverwriteArgs {
+			if key == p.key {
+				overwrite = true
+
+				break
+			}
+		}
+
+		if overwrite {
+			c.Set(p.key, p)
+
+			continue
+		}
+
 		for _, v := range p.values {
 			c.Append(p.key, v)
 		}

procfs/cmdline_test.go

@@ -146,21 +146,36 @@ func (suite *KernelSuite) TestCmdlineAppendAll() {
 	for _, t := range []struct {
 		initial  string
 		params   []string
+		opts     []AppendAllOption
 		expected string
 	}{
 		{
 			"ip=dhcp console=x root=/dev/sdc",
 			[]string{"root=/dev/sda", "root=/dev/sdb"},
+			nil,
 			"ip=dhcp console=x root=/dev/sdc root=/dev/sda root=/dev/sdb",
 		},
 		{
 			"root=/dev/sdb",
 			[]string{"this=that=those"},
+			nil,
 			"root=/dev/sdb this=that=those",
 		},
+		{
+			"console=tty0 console=ttyS0 root=/dev/sdb",
+			[]string{"console=tty0", "console=ttyS1,115200", "nogui"},
+			nil,
+			"console=tty0 console=ttyS0 console=tty0 console=ttyS1,115200 root=/dev/sdb nogui",
+		},
+		{
+			"console=tty0 console=ttyS0 root=/dev/sdb",
+			[]string{"console=tty0", "console=ttyS1,115200", "nogui"},
+			[]AppendAllOption{WithOverwriteArgs("console")},
+			"console=tty0 console=ttyS1,115200 root=/dev/sdb nogui",
+		},
 	} {
 		cmdline := NewCmdline(t.initial)
-		err := cmdline.AppendAll(t.params)
+		err := cmdline.AppendAll(t.params, t.opts...)
 		visited := map[string]bool{}
 
 		for _, p := range cmdline.Parameters {