[op] Move SignalStack to abi/linux package.

Updates #214

PiperOrigin-RevId: 378594929

4 files changed, 12 insertions, 35 deletions

diff --git a/pkg/sentry/kernel/task.go b/pkg/sentry/kernel/task.go
index be1371855..9290dc52b 100644
--- a/pkg/sentry/kernel/task.go
+++ b/pkg/sentry/kernel/task.go
@@ -151,7 +151,7 @@ type Task struct {
 	// which the SA_ONSTACK flag is set.
 	//
 	// signalStack is exclusive to the task goroutine.
-	signalStack arch.SignalStack
+	signalStack linux.SignalStack
 
 	// signalQueue is a set of registered waiters for signal-related events.
 	//
diff --git a/pkg/sentry/kernel/task_exec.go b/pkg/sentry/kernel/task_exec.go
index d9897e802..cf8571262 100644
--- a/pkg/sentry/kernel/task_exec.go
+++ b/pkg/sentry/kernel/task_exec.go
@@ -66,7 +66,6 @@ package kernel
 
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/mm"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
@@ -181,7 +180,7 @@ func (r *runSyscallAfterExecStop) execute(t *Task) taskRunState {
 	t.tg.signalHandlers = t.tg.signalHandlers.CopyForExec()
 	t.endStopCond.L = &t.tg.signalHandlers.mu
 	// "Any alternate signal stack is not preserved (sigaltstack(2))." - execve(2)
-	t.signalStack = arch.SignalStack{Flags: arch.SignalStackFlagDisable}
+	t.signalStack = linux.SignalStack{Flags: linux.SS_DISABLE}
 	// "The termination signal is reset to SIGCHLD (see clone(2))."
 	t.tg.terminationSignal = linux.SIGCHLD
 	// execed indicates that the process can no longer join a process group
diff --git a/pkg/sentry/kernel/task_signals.go b/pkg/sentry/kernel/task_signals.go
index 466256fe4..b0ed0e023 100644
--- a/pkg/sentry/kernel/task_signals.go
+++ b/pkg/sentry/kernel/task_signals.go
@@ -249,7 +249,7 @@ func (t *Task) deliverSignalToHandler(info *arch.SignalInfo, act linux.SigAction
 	// handler expects to see in its ucontext (even if it's not in use).
 	alt := t.signalStack
 	if act.Flags&linux.SA_ONSTACK != 0 && alt.IsEnabled() {
-		alt.SetOnStack()
+		alt.Flags |= linux.SS_ONSTACK
 		if !alt.Contains(sp) {
 			sp = hostarch.Addr(alt.Top())
 		}
@@ -641,17 +641,17 @@ func (t *Task) SetSavedSignalMask(mask linux.SignalSet) {
 }
 
 // SignalStack returns the task-private signal stack.
-func (t *Task) SignalStack() arch.SignalStack {
+func (t *Task) SignalStack() linux.SignalStack {
 	t.p.PullFullState(t.MemoryManager().AddressSpace(), t.Arch())
 	alt := t.signalStack
 	if t.onSignalStack(alt) {
-		alt.Flags |= arch.SignalStackFlagOnStack
+		alt.Flags |= linux.SS_ONSTACK
 	}
 	return alt
 }
 
 // onSignalStack returns true if the task is executing on the given signal stack.
-func (t *Task) onSignalStack(alt arch.SignalStack) bool {
+func (t *Task) onSignalStack(alt linux.SignalStack) bool {
 	sp := hostarch.Addr(t.Arch().Stack())
 	return alt.Contains(sp)
 }
@@ -661,20 +661,20 @@ func (t *Task) onSignalStack(alt arch.SignalStack) bool {
 // This value may not be changed if the task is currently executing on the
 // signal stack, i.e. if t.onSignalStack returns true. In this case, this
 // function will return false. Otherwise, true is returned.
-func (t *Task) SetSignalStack(alt arch.SignalStack) bool {
+func (t *Task) SetSignalStack(alt linux.SignalStack) bool {
 	// Check that we're not executing on the stack.
 	if t.onSignalStack(t.signalStack) {
 		return false
 	}
 
-	if alt.Flags&arch.SignalStackFlagDisable != 0 {
+	if alt.Flags&linux.SS_DISABLE != 0 {
 		// Don't record anything beyond the flags.
-		t.signalStack = arch.SignalStack{
-			Flags: arch.SignalStackFlagDisable,
+		t.signalStack = linux.SignalStack{
+			Flags: linux.SS_DISABLE,
 		}
 	} else {
 		// Mask out irrelevant parts: only disable matters.
-		alt.Flags &= arch.SignalStackFlagDisable
+		alt.Flags &= linux.SS_DISABLE
 		t.signalStack = alt
 	}
 	return true
@@ -718,27 +718,6 @@ func (tg *ThreadGroup) SetSigAction(sig linux.Signal, actptr *linux.SigAction) (
 	return oldact, nil
 }
 
-// CopyOutSignalStack converts the given SignalStack into an
-// architecture-specific type and then copies it out to task memory.
-func (t *Task) CopyOutSignalStack(addr hostarch.Addr, s *arch.SignalStack) error {
-	n := t.Arch().NewSignalStack()
-	n.SerializeFrom(s)
-	_, err := n.CopyOut(t, addr)
-	return err
-}
-
-// CopyInSignalStack copies an architecture-specific stack_t from task memory
-// and then converts it into a SignalStack.
-func (t *Task) CopyInSignalStack(addr hostarch.Addr) (arch.SignalStack, error) {
-	n := t.Arch().NewSignalStack()
-	var s arch.SignalStack
-	if _, err := n.CopyIn(t, addr); err != nil {
-		return s, err
-	}
-	n.DeserializeTo(&s)
-	return s, nil
-}
-
 // groupStop is a TaskStop placed on tasks that have received a stop signal
 // (SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU). (The term "group-stop" originates from
 // the ptrace man page.)
diff --git a/pkg/sentry/kernel/task_start.go b/pkg/sentry/kernel/task_start.go
index 32031cd70..41fd2d471 100644
--- a/pkg/sentry/kernel/task_start.go
+++ b/pkg/sentry/kernel/task_start.go
@@ -18,7 +18,6 @@ import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/hostarch"
-	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/inet"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/futex"
@@ -131,7 +130,7 @@ func (ts *TaskSet) newTask(cfg *TaskConfig) (*Task, error) {
 		runState:           (*runApp)(nil),
 		interruptChan:      make(chan struct{}, 1),
 		signalMask:         cfg.SignalMask,
-		signalStack:        arch.SignalStack{Flags: arch.SignalStackFlagDisable},
+		signalStack:        linux.SignalStack{Flags: linux.SS_DISABLE},
 		image:              *image,
 		fsContext:          cfg.FSContext,
 		fdTable:            cfg.FDTable,