hst: use hsu userid for share path suffix

The privileged user is identifier to hakurei through its hsu userid. Using the kernel uid here makes little sense and is a leftover design choice from before hsu was implemented.

Closes #7.

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

12 files changed, 53 insertions, 34 deletions

diff --git a/cmd/hpkg/test/test.py b/cmd/hpkg/test/test.py
index 5a199acc..d491def3 100644
--- a/cmd/hpkg/test/test.py
+++ b/cmd/hpkg/test/test.py
@@ -90,7 +90,7 @@ machine.wait_for_file("/tmp/hpkg-install-ok")
 swaymsg("exec hpkg -v start org.codeberg.dnkl.foot")
 wait_for_window("hakurei@machine-foot")
 machine.send_chars("clear; wayland-info && touch /tmp/success-client\n")
-machine.wait_for_file("/tmp/hakurei.1000/tmpdir/2/success-client")
+machine.wait_for_file("/tmp/hakurei.0/tmpdir/2/success-client")
 collect_state_ui("app_wayland")
 check_state("foot", {"wayland": True, "dbus": True, "pulse": True})
 # Verify acl on XDG_RUNTIME_DIR:
diff --git a/hst/hst.go b/hst/hst.go
index 6549450c..d9c1168b 100644
--- a/hst/hst.go
+++ b/hst/hst.go
@@ -12,16 +12,18 @@ import (
 type Paths struct {
 	// temporary directory returned by [os.TempDir] (usually `/tmp`)
 	TempDir *container.Absolute `json:"temp_dir"`
-	// path to shared directory (usually `/tmp/hakurei.%d`)
+	// path to shared directory (usually `/tmp/hakurei.%d`, [Info.User])
 	SharePath *container.Absolute `json:"share_path"`
-	// XDG_RUNTIME_DIR value (usually `/run/user/%d`)
+	// XDG_RUNTIME_DIR value (usually `/run/user/%d`, uid)
 	RuntimePath *container.Absolute `json:"runtime_path"`
 	// application runtime directory (usually `/run/user/%d/hakurei`)
 	RunDirPath *container.Absolute `json:"run_dir_path"`
 }
 
 type Info struct {
+	// User is the userid according to hsu.
 	User int `json:"user"`
+
 	Paths
 }
 
diff --git a/internal/sys/interface.go b/internal/sys/interface.go
index 5dbe18e6..ed765ece 100644
--- a/internal/sys/interface.go
+++ b/internal/sys/interface.go
@@ -22,9 +22,9 @@ type State interface {
 	LookupEnv(key string) (string, bool)
 	// TempDir provides [os.TempDir].
 	TempDir() string
-	// LookPath provides [exec.LookPath].
+	// LookPath provides exec.LookPath.
 	LookPath(file string) (string, error)
-	// MustExecutable provides [proc.MustExecutable].
+	// MustExecutable provides [container.MustExecutable].
 	MustExecutable() string
 	// LookupGroup provides [user.LookupGroup].
 	LookupGroup(name string) (*user.Group, error)
@@ -32,9 +32,9 @@ type State interface {
 	ReadDir(name string) ([]fs.DirEntry, error)
 	// Stat provides [os.Stat].
 	Stat(name string) (fs.FileInfo, error)
-	// Open provides [os.Open]
+	// Open provides [os.Open].
 	Open(name string) (fs.File, error)
-	// EvalSymlinks provides [filepath.EvalSymlinks]
+	// EvalSymlinks provides filepath.EvalSymlinks.
 	EvalSymlinks(path string) (string, error)
 	// Exit provides [os.Exit].
 	Exit(code int)
@@ -45,19 +45,28 @@ type State interface {
 	// Paths returns a populated [hst.Paths] struct.
 	Paths() hst.Paths
 	// Uid invokes hsu and returns target uid.
-	// Any errors returned by Uid is already wrapped [fmsg.BaseError].
-	Uid(aid int) (int, error)
+	// Any errors returned by Uid is already wrapped [hlog.BaseError].
+	Uid(identity int) (int, error)
+}
+
+// GetUserID obtains user id from hsu by querying uid of identity 0.
+func GetUserID(os State) (int, error) {
+	if uid, err := os.Uid(0); err != nil {
+		return -1, err
+	} else {
+		return (uid / 10000) - 100, nil
+	}
 }
 
 // CopyPaths is a generic implementation of [hst.Paths].
-func CopyPaths(os State, v *hst.Paths) {
+func CopyPaths(os State, v *hst.Paths, userid int) {
 	if tempDir, err := container.NewAbs(os.TempDir()); err != nil {
 		log.Fatalf("invalid TMPDIR: %v", err)
 	} else {
 		v.TempDir = tempDir
 	}
 
-	v.SharePath = v.TempDir.Append("hakurei." + strconv.Itoa(os.Getuid()))
+	v.SharePath = v.TempDir.Append("hakurei." + strconv.Itoa(userid))
 	hlog.Verbosef("process share directory at %q", v.SharePath)
 
 	r, _ := os.LookupEnv(xdgRuntimeDir)
diff --git a/internal/sys/std.go b/internal/sys/std.go
index 89fdd289..828cbc45 100644
--- a/internal/sys/std.go
+++ b/internal/sys/std.go
@@ -49,11 +49,19 @@ func (s *Std) Printf(format string, v ...any)               { hlog.Verbosef(form
 const xdgRuntimeDir = "XDG_RUNTIME_DIR"
 
 func (s *Std) Paths() hst.Paths {
-	s.pathsOnce.Do(func() { CopyPaths(s, &s.paths) })
+	s.pathsOnce.Do(func() {
+		if userid, err := GetUserID(s); err != nil {
+			hlog.PrintBaseError(err, "cannot obtain user id from hsu:")
+			hlog.BeforeExit()
+			s.Exit(1)
+		} else {
+			CopyPaths(s, &s.paths, userid)
+		}
+	})
 	return s.paths
 }
 
-func (s *Std) Uid(aid int) (int, error) {
+func (s *Std) Uid(identity int) (int, error) {
 	s.uidOnce.Do(func() {
 		s.uidCopy = make(map[int]struct {
 			uid int
@@ -63,7 +71,7 @@ func (s *Std) Uid(aid int) (int, error) {
 
 	{
 		s.uidMu.RLock()
-		u, ok := s.uidCopy[aid]
+		u, ok := s.uidCopy[identity]
 		s.uidMu.RUnlock()
 		if ok {
 			return u.uid, u.err
@@ -77,7 +85,7 @@ func (s *Std) Uid(aid int) (int, error) {
 		uid int
 		err error
 	}{}
-	defer func() { s.uidCopy[aid] = u }()
+	defer func() { s.uidCopy[identity] = u }()
 
 	u.uid = -1
 	hsuPath := internal.MustHsuPath()
@@ -85,7 +93,7 @@ func (s *Std) Uid(aid int) (int, error) {
 	cmd := exec.Command(hsuPath)
 	cmd.Path = hsuPath
 	cmd.Stderr = os.Stderr // pass through fatal messages
-	cmd.Env = []string{"HAKUREI_APP_ID=" + strconv.Itoa(aid)}
+	cmd.Env = []string{"HAKUREI_APP_ID=" + strconv.Itoa(identity)}
 	cmd.Dir = container.FHSRoot
 	var (
 		p         []byte
@@ -95,7 +103,7 @@ func (s *Std) Uid(aid int) (int, error) {
 	if p, u.err = cmd.Output(); u.err == nil {
 		u.uid, u.err = strconv.Atoi(string(p))
 		if u.err != nil {
-			u.err = hlog.WrapErrSuffix(u.err, "cannot parse uid from hsu:")
+			u.err = hlog.WrapErr(u.err, "invalid uid string from hsu")
 		}
 	} else if errors.As(u.err, &exitError) && exitError != nil && exitError.ExitCode() == 1 {
 		u.err = hlog.WrapErr(syscall.EACCES, "") // hsu prints to stderr in this case
diff --git a/test/sandbox/case/device.nix b/test/sandbox/case/device.nix
index 5d607d92..831b6ab2 100644
--- a/test/sandbox/case/device.nix
+++ b/test/sandbox/case/device.nix
@@ -230,8 +230,8 @@ in
       (ent "/etc" ignore "ro,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent "/var/lib/hakurei/u0/a4" "/var/lib/hakurei/u0/a4" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent "/" "/run/user" "rw,nosuid,nodev,relatime" "tmpfs" "ephemeral" "rw,size=4k,mode=755,uid=1000004,gid=1000004")
-      (ent "/tmp/hakurei.1000/runtime/4" "/run/user/65534" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
-      (ent "/tmp/hakurei.1000/tmpdir/4" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/runtime/4" "/run/user/65534" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/tmpdir/4" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent ignore "/etc/passwd" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000004,gid=1000004")
       (ent ignore "/etc/group" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000004,gid=1000004")
       (ent ignore "/run/user/65534/wayland-0" "ro,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
diff --git a/test/sandbox/case/mapuid.nix b/test/sandbox/case/mapuid.nix
index c18bf796..486d4390 100644
--- a/test/sandbox/case/mapuid.nix
+++ b/test/sandbox/case/mapuid.nix
@@ -257,8 +257,8 @@ in
       (ent "/etc" ignore "ro,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent "/var/lib/hakurei/u0/a3" "/var/lib/hakurei/u0/a3" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent "/" "/run/user" "rw,nosuid,nodev,relatime" "tmpfs" "ephemeral" "rw,size=4k,mode=755,uid=1000003,gid=1000003")
-      (ent "/tmp/hakurei.1000/runtime/3" "/run/user/1000" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
-      (ent "/tmp/hakurei.1000/tmpdir/3" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/runtime/3" "/run/user/1000" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/tmpdir/3" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent ignore "/etc/passwd" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000003,gid=1000003")
       (ent ignore "/etc/group" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000003,gid=1000003")
       (ent ignore "/run/user/1000/wayland-0" "ro,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
diff --git a/test/sandbox/case/pd.nix b/test/sandbox/case/pd.nix
index 14b62b40..6bad3e73 100644
--- a/test/sandbox/case/pd.nix
+++ b/test/sandbox/case/pd.nix
@@ -186,8 +186,8 @@
       (ent "/" "/run/user/1000" "rw,nosuid,nodev,relatime" "tmpfs" "ephemeral" "rw,size=8k,mode=755,uid=1000000,gid=1000000")
       (ent "/" "/run/dbus" "rw,nosuid,nodev,relatime" "tmpfs" "ephemeral" "rw,size=8k,mode=755,uid=1000000,gid=1000000")
       (ent "/" "/run/user" "rw,nosuid,nodev,relatime" "tmpfs" "ephemeral" "rw,size=4k,mode=755,uid=1000000,gid=1000000")
-      (ent "/tmp/hakurei.1000/runtime/0" "/run/user/65534" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
-      (ent "/tmp/hakurei.1000/tmpdir/0" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/runtime/0" "/run/user/65534" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/tmpdir/0" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent ignore "/etc/passwd" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000000,gid=1000000")
       (ent ignore "/etc/group" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000000,gid=1000000")
     ];
diff --git a/test/sandbox/case/pdlike.nix b/test/sandbox/case/pdlike.nix
index c87ab46c..1fdc5925 100644
--- a/test/sandbox/case/pdlike.nix
+++ b/test/sandbox/case/pdlike.nix
@@ -252,8 +252,8 @@ in
       (ent "/etc" ignore "ro,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent "/var/lib/hakurei/u0/a5" "/var/lib/hakurei/u0/a5" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent "/" "/run/user" "rw,nosuid,nodev,relatime" "tmpfs" "ephemeral" "rw,size=4k,mode=755,uid=1000005,gid=1000005")
-      (ent "/tmp/hakurei.1000/runtime/5" "/run/user/65534" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
-      (ent "/tmp/hakurei.1000/tmpdir/5" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/runtime/5" "/run/user/65534" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/tmpdir/5" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent ignore "/etc/passwd" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000005,gid=1000005")
       (ent ignore "/etc/group" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000005,gid=1000005")
       (ent ignore "/run/user/65534/wayland-0" "ro,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
diff --git a/test/sandbox/case/preset.nix b/test/sandbox/case/preset.nix
index d8f6879e..721659f5 100644
--- a/test/sandbox/case/preset.nix
+++ b/test/sandbox/case/preset.nix
@@ -250,8 +250,8 @@ in
       (ent "/etc" ignore "ro,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent "/var/lib/hakurei/u0/a1" "/var/lib/hakurei/u0/a1" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent "/" "/run/user" "rw,nosuid,nodev,relatime" "tmpfs" "ephemeral" "rw,size=4k,mode=755,uid=1000001,gid=1000001")
-      (ent "/tmp/hakurei.1000/runtime/1" "/run/user/65534" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
-      (ent "/tmp/hakurei.1000/tmpdir/1" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/runtime/1" "/run/user/65534" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/tmpdir/1" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent ignore "/etc/passwd" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000001,gid=1000001")
       (ent ignore "/etc/group" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000001,gid=1000001")
       (ent ignore "/run/user/65534/wayland-0" "ro,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
diff --git a/test/sandbox/case/tty.nix b/test/sandbox/case/tty.nix
index 15b60ad0..0aed7831 100644
--- a/test/sandbox/case/tty.nix
+++ b/test/sandbox/case/tty.nix
@@ -262,8 +262,8 @@ in
       (ent "/etc" ignore "ro,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent "/var/lib/hakurei/u0/a2" "/var/lib/hakurei/u0/a2" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent "/" "/run/user" "rw,nosuid,nodev,relatime" "tmpfs" "ephemeral" "rw,size=4k,mode=755,uid=1000002,gid=1000002")
-      (ent "/tmp/hakurei.1000/runtime/2" "/run/user/65534" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
-      (ent "/tmp/hakurei.1000/tmpdir/2" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/runtime/2" "/run/user/65534" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
+      (ent "/tmp/hakurei.0/tmpdir/2" "/tmp" "rw,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
       (ent ignore "/etc/passwd" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000002,gid=1000002")
       (ent ignore "/etc/group" "ro,nosuid,nodev,relatime" "tmpfs" "rootfs" "rw,uid=1000002,gid=1000002")
       (ent ignore "/run/user/65534/wayland-0" "ro,nosuid,nodev,relatime" "ext4" "/dev/disk/by-label/nixos" "rw")
diff --git a/test/sandbox/test.py b/test/sandbox/test.py
index 6ae3e145..5997b890 100644
--- a/test/sandbox/test.py
+++ b/test/sandbox/test.py
@@ -60,7 +60,7 @@ check_offset = 0
 def check_sandbox(name):
     global check_offset
     swaymsg(f"exec script /dev/null -E always -qec check-sandbox-{name}")
-    machine.wait_for_file(f"/tmp/hakurei.1000/tmpdir/{check_offset}/sandbox-ok", timeout=15)
+    machine.wait_for_file(f"/tmp/hakurei.0/tmpdir/{check_offset}/sandbox-ok", timeout=15)
     check_filter(check_offset, name, "hakurei-test")
     check_offset += 1
 
diff --git a/test/test.py b/test/test.py
index c02766c7..96253534 100644
--- a/test/test.py
+++ b/test/test.py
@@ -113,12 +113,12 @@ def aid(offset):
 
 
 def tmpdir_path(offset, name):
-    return f"/tmp/hakurei.1000/tmpdir/{aid(offset)}/{name}"
+    return f"/tmp/hakurei.0/tmpdir/{aid(offset)}/{name}"
 
 
 # Start hakurei permissive defaults outside Wayland session:
 print(machine.succeed("sudo -u alice -i hakurei -v run -a 0 touch /tmp/pd-bare-ok"))
-machine.wait_for_file("/tmp/hakurei.1000/tmpdir/0/pd-bare-ok", timeout=5)
+machine.wait_for_file("/tmp/hakurei.0/tmpdir/0/pd-bare-ok", timeout=5)
 
 # Verify silent output permissive defaults:
 output = machine.succeed("sudo -u alice -i hakurei run -a 0 true &>/dev/stdout")
@@ -131,8 +131,8 @@ def silent_output_interrupt(flags):
     wait_for_window("alice@machine")
     # aid 0 does not have home-manager
     machine.send_chars(f"exec hakurei run {flags}-a 0 sh -c 'export PATH=/run/current-system/sw/bin:$PATH && touch /tmp/pd-silent-ready && sleep infinity' &>/tmp/pd-silent\n")
-    machine.wait_for_file("/tmp/hakurei.1000/tmpdir/0/pd-silent-ready", timeout=15)
-    machine.succeed("rm /tmp/hakurei.1000/tmpdir/0/pd-silent-ready")
+    machine.wait_for_file("/tmp/hakurei.0/tmpdir/0/pd-silent-ready", timeout=15)
+    machine.succeed("rm /tmp/hakurei.0/tmpdir/0/pd-silent-ready")
     machine.send_key("ctrl-c")
     machine.wait_until_fails("pgrep foot", timeout=5)
     machine.wait_until_fails(f"pgrep -u alice -f 'hakurei run {flags}-a 0 '", timeout=5)