runc exec: fix setting process.ioPriority

Commit bfbd030 added IOPriority property into both Config and Process,
but forgot to add a mechanism to actually use Process.IOPriority.
As a result, runc exec does not set Process.IOPriority ever.

Fix it, and a test case (which fails before the fix).

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

libcontainer/container_linux.go

@@ -698,6 +698,7 @@ func (c *Container) newInitConfig(process *Process) *initConfig {
 		AppArmorProfile:  c.config.AppArmorProfile,
 		ProcessLabel:     c.config.ProcessLabel,
 		Rlimits:          c.config.Rlimits,
+		IOPriority:       c.config.IOPriority,
 		CreateConsole:    process.ConsoleSocket != nil,
 		ConsoleWidth:     process.ConsoleWidth,
 		ConsoleHeight:    process.ConsoleHeight,
@@ -720,6 +721,9 @@ func (c *Container) newInitConfig(process *Process) *initConfig {
 	if len(process.Rlimits) > 0 {
 		cfg.Rlimits = process.Rlimits
 	}
+	if process.IOPriority != nil {
+		cfg.IOPriority = process.IOPriority
+	}
 
 	// Set misc properties.
 

libcontainer/init_linux.go

@@ -81,6 +81,7 @@ type initConfig struct {
 	NoNewPrivileges bool                  `json:"no_new_privileges"`
 	ProcessLabel    string                `json:"process_label"`
 	Rlimits         []configs.Rlimit      `json:"rlimits"`
+	IOPriority      *configs.IOPriority   `json:"io_priority,omitempty"`
 
 	// Miscellaneous properties, filled in by [Container.newInitConfig]
 	// unless documented otherwise.
@@ -672,7 +673,7 @@ func setupScheduler(config *configs.Config) error {
 	return nil
 }
 
-func setupIOPriority(config *configs.Config) error {
+func setupIOPriority(config *initConfig) error {
 	const ioprioWhoPgrp = 1
 
 	ioprio := config.IOPriority

libcontainer/setns_init_linux.go

@@ -76,7 +76,7 @@ func (l *linuxSetnsInit) Init() error {
 		return err
 	}
 
-	if err := setupIOPriority(l.config.Config); err != nil {
+	if err := setupIOPriority(l.config); err != nil {
 		return err
 	}
 	// Tell our parent that we're ready to exec. This must be done before the

libcontainer/standard_init_linux.go

@@ -160,7 +160,7 @@ func (l *linuxStandardInit) Init() error {
 		return err
 	}
 
-	if err := setupIOPriority(l.config.Config); err != nil {
+	if err := setupIOPriority(l.config); err != nil {
 		return err
 	}
 

tests/integration/ioprio.bats

@@ -22,9 +22,23 @@ function teardown() {
 	[ "$status" -eq 0 ]
 	[[ "$output" = *'best-effort: prio 4'* ]]
 
-	# Check the process made from the exec command.
+	# Check the process made from the exec command,
+	# which should derive ioprio from config.json.
 	runc exec test_ioprio ionice
 	[ "$status" -eq 0 ]
-
 	[[ "$output" = *'best-effort: prio 4'* ]]
+
+	# Run exec with a different priority.
+	proc='
+{
+	"terminal": false,
+	"ioPriority": {
+		"class": "IOPRIO_CLASS_IDLE"
+	},
+	"args": [ "/usr/bin/ionice" ],
+	"cwd": "/"
+}'
+	runc exec --process <(echo "$proc") test_ioprio
+	[ "$status" -eq 0 ]
+	[[ "$output" = *'idle'* ]]
 }