internal: remove sys package

This package is replaced by container/stub. Remove and replace it with unexported implementation for the upcoming test suite rewrite.

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

internal/app/dispatcher.go

@@ -0,0 +1,99 @@
+package app
+
+import (
+	"log"
+	"os"
+	"os/exec"
+	"os/user"
+	"path/filepath"
+
+	"hakurei.app/container"
+	"hakurei.app/internal"
+	"hakurei.app/internal/hlog"
+)
+
+// syscallDispatcher provides methods that make state-dependent system calls as part of their behaviour.
+type syscallDispatcher interface {
+	// new starts a goroutine with a new instance of syscallDispatcher.
+	// A syscallDispatcher must never be used in any goroutine other than the one owning it,
+	// just synchronising access is not enough, as this is for test instrumentation.
+	new(f func(k syscallDispatcher))
+
+	// getuid provides [os.Getuid].
+	getuid() int
+	// getgid provides [os.Getgid].
+	getgid() int
+	// lookupEnv provides [os.LookupEnv].
+	lookupEnv(key string) (string, bool)
+	// stat provides [os.Stat].
+	stat(name string) (os.FileInfo, error)
+	// readdir provides [os.ReadDir].
+	readdir(name string) ([]os.DirEntry, error)
+	// tempdir provides [os.TempDir].
+	tempdir() string
+
+	// evalSymlinks provides [filepath.EvalSymlinks].
+	evalSymlinks(path string) (string, error)
+
+	// lookPath provides exec.LookPath.
+	lookPath(file string) (string, error)
+
+	// lookupGroupId calls [user.LookupGroup] and returns the Gid field of the resulting [user.Group] struct.
+	lookupGroupId(name string) (string, error)
+
+	// cmdOutput provides the Output method of [exec.Cmd].
+	cmdOutput(cmd *exec.Cmd) ([]byte, error)
+
+	// overflowUid provides [container.OverflowUid].
+	overflowUid() int
+	// overflowGid provides [container.OverflowGid].
+	overflowGid() int
+
+	// mustHsuPath provides [internal.MustHsuPath].
+	mustHsuPath() string
+
+	// fatalf provides [log.Fatalf].
+	fatalf(format string, v ...any)
+
+	isVerbose() bool
+	verbose(v ...any)
+	verbosef(format string, v ...any)
+}
+
+// direct implements syscallDispatcher on the current kernel.
+type direct struct{}
+
+func (k direct) new(f func(k syscallDispatcher)) { go f(k) }
+
+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) }
+func (direct) stat(name string) (os.FileInfo, error)      { return os.Stat(name) }
+func (direct) readdir(name string) ([]os.DirEntry, error) { return os.ReadDir(name) }
+func (direct) tempdir() string                            { return os.TempDir() }
+
+func (direct) evalSymlinks(path string) (string, error) { return filepath.EvalSymlinks(path) }
+
+func (direct) lookPath(file string) (string, error) { return exec.LookPath(file) }
+
+func (direct) lookupGroupId(name string) (gid string, err error) {
+	var group *user.Group
+	group, err = user.LookupGroup(name)
+	if group != nil {
+		gid = group.Gid
+	}
+	return
+}
+
+func (direct) cmdOutput(cmd *exec.Cmd) ([]byte, error) { return cmd.Output() }
+
+func (direct) overflowUid() int { return container.OverflowUid() }
+func (direct) overflowGid() int { return container.OverflowGid() }
+
+func (direct) mustHsuPath() string { return internal.MustHsuPath() }
+
+func (direct) fatalf(format string, v ...any) { log.Fatalf(format, v...) }
+
+func (k direct) isVerbose() bool                { return hlog.Load() }
+func (direct) verbose(v ...any)                 { hlog.Verbose(v...) }
+func (direct) verbosef(format string, v ...any) { hlog.Verbosef(format, v...) }