internal/app: relocate state initialisation

This is useful for testing.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/app/app_test.go

@@ -450,15 +450,7 @@ func TestApp(t *testing.T) {
 
 			var gotSys *system.I
 			{
-				sPriv := outcomeState{
-					ID:        &tc.id,
-					Identity:  tc.config.Identity,
-					UserID:    (&Hsu{k: tc.k}).MustIDMsg(msg),
-					EnvPaths:  copyPaths(tc.k),
-					Container: tc.config.Container,
-				}
-
-				sPriv.populateEarly(tc.k, msg)
+				sPriv := newOutcomeState(tc.k, msg, &tc.id, tc.config, &Hsu{k: tc.k})
 				if err := sPriv.populateLocal(tc.k, msg); err != nil {
 					t.Fatalf("populateLocal: error = %#v", err)
 				}
@@ -574,6 +566,7 @@ type stubNixOS struct {
 
 func (k *stubNixOS) new(func(k syscallDispatcher)) { panic("not implemented") }
 
+func (k *stubNixOS) getpid() int { return 0xdeadbeef }
 func (k *stubNixOS) getuid() int { return 1971 }
 func (k *stubNixOS) getgid() int { return 100 }
 

internal/app/dispatcher.go

@@ -29,6 +29,8 @@ type syscallDispatcher interface {
 	// just synchronising access is not enough, as this is for test instrumentation.
 	new(f func(k syscallDispatcher))
 
+	// getpid provides [os.Getpid].
+	getpid() int
 	// getuid provides [os.Getuid].
 	getuid() int
 	// getgid provides [os.Getgid].
@@ -70,6 +72,7 @@ type direct struct{}
 
 func (k direct) new(f func(k syscallDispatcher)) { go f(k) }
 
+func (direct) getpid() int                                { return os.Getpid() }
 func (direct) getuid() int                                { return os.Getuid() }
 func (direct) getgid() int                                { return os.Getgid() }
 func (direct) lookupEnv(key string) (string, bool)        { return os.LookupEnv(key) }

internal/app/dispatcher_test.go

@@ -11,6 +11,7 @@ import (
 type panicDispatcher struct{}
 
 func (panicDispatcher) new(func(k syscallDispatcher))         { panic("unreachable") }
+func (panicDispatcher) getpid() int                           { panic("unreachable") }
 func (panicDispatcher) getuid() int                           { panic("unreachable") }
 func (panicDispatcher) getgid() int                           { panic("unreachable") }
 func (panicDispatcher) lookupEnv(string) (string, bool)       { panic("unreachable") }

internal/app/finalise.go

@@ -68,14 +68,7 @@ func (k *outcome) finalise(ctx context.Context, msg message.Msg, id *state.ID, c
 	}
 
 	// early validation complete at this point
-	s := outcomeState{
-		ID:        id,
-		Identity:  config.Identity,
-		UserID:    (&Hsu{k: k}).MustIDMsg(msg),
-		EnvPaths:  copyPaths(k.syscallDispatcher),
-		Container: config.Container,
-	}
-	s.populateEarly(k.syscallDispatcher, msg)
+	s := newOutcomeState(k.syscallDispatcher, msg, id, config, &Hsu{k: k})
 	if err := s.populateLocal(k.syscallDispatcher, msg); err != nil {
 		return err
 	}
@@ -87,7 +80,7 @@ func (k *outcome) finalise(ctx context.Context, msg message.Msg, id *state.ID, c
 
 	k.sys = sys
 	k.supp = supp
-	k.state = &s
+	k.state = s
 	k.config = config
 	return nil
 }

internal/app/outcome.go

@@ -2,7 +2,6 @@ package app
 
 import (
 	"errors"
-	"os"
 	"strconv"
 
 	"hakurei.app/container"
@@ -72,10 +71,16 @@ func (s *outcomeState) valid() bool {
 		s.EnvPaths != nil
 }
 
-// populateEarly populates exported fields via syscallDispatcher.
-// This must only be called from the priv side.
-func (s *outcomeState) populateEarly(k syscallDispatcher, msg message.Msg) {
-	s.Shim = &shimParams{PrivPID: os.Getpid(), Verbose: msg.IsVerbose()}
+// newOutcomeState returns the address of a new outcomeState with its exported fields populated via syscallDispatcher.
+func newOutcomeState(k syscallDispatcher, msg message.Msg, id *state.ID, config *hst.Config, hsu *Hsu) *outcomeState {
+	s := outcomeState{
+		ID:        id,
+		Identity:  config.Identity,
+		UserID:    hsu.MustIDMsg(msg),
+		EnvPaths:  copyPaths(k),
+		Container: config.Container,
+	}
+	s.Shim = &shimParams{PrivPID: k.getpid(), Verbose: msg.IsVerbose()}
 
 	// enforce bounds and default early
 	if s.Container.WaitDelay < 0 {
@@ -94,7 +99,7 @@ func (s *outcomeState) populateEarly(k syscallDispatcher, msg message.Msg) {
 		s.Mapuid, s.Mapgid = k.overflowUid(msg), k.overflowGid(msg)
 	}
 
-	return
+	return &s
 }
 
 // populateLocal populates unexported fields from transmitted exported fields.