From 4dcb10d9f1894ef78b4780b66bce3c738cc0ce36 Mon Sep 17 00:00:00 2001
From: Stephen Hellings <stephen@hellings.cc>
Date: Mon, 9 Mar 2026 11:21:08 -0400
Subject: [PATCH] Attempt 3 to fix launching permission denied

---
 config.example.toml |  4 ++--
 src/config.rs       | 26 ++++++++++++++++++++----
 src/main.rs         | 48 ++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 69 insertions(+), 9 deletions(-)

diff --git a/config.example.toml b/config.example.toml
index f312d72..0a0eb33 100644
--- a/config.example.toml
+++ b/config.example.toml
@@ -1,10 +1,10 @@
 [compositor]
 socket_name = "wo-0"
-ipc_socket = "/run/user/1000/wo-ipc.sock"
+ipc_socket = "$XDG_RUNTIME_DIR/wo-ipc.sock"
 electron_path = "electron"
 background = [0.08, 0.10, 0.12, 1.0]
 enable_portal = true
-portal_socket = "/run/user/1000/wo-portal.sock"
+portal_socket = "$XDG_RUNTIME_DIR/wo-portal.sock"
 enable_syscalls = true
 focus_notify = true
 
diff --git a/src/config.rs b/src/config.rs
index d9b86e3..3b3db92 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -246,10 +246,17 @@ impl ApplicationConfig {
 // Defaults
 
 fn default_socket_name() -> String { "wo-0".into() }
-fn default_ipc_socket()  -> String { "/run/user/1000/wo-ipc.sock".into() }
 fn default_electron_path() -> String { "electron".into() }
 fn default_background()  -> [f32; 4] { [0.1, 0.1, 0.1, 1.0] }
-fn default_portal_socket() -> String { "/run/user/1000/wo-portal.sock".into() }
+
+/// Returns $XDG_RUNTIME_DIR, falling back to /run/user/<uid>.
+fn runtime_dir() -> String {
+    std::env::var("XDG_RUNTIME_DIR")
+        .unwrap_or_else(|_| format!("/run/user/{}", unsafe { libc::getuid() }))
+}
+
+fn default_ipc_socket()    -> String { format!("{}/wo-ipc.sock",    runtime_dir()) }
+fn default_portal_socket() -> String { format!("{}/wo-portal.sock", runtime_dir()) }
 fn default_width()       -> u32 { 1920 }
 fn default_height()      -> u32 { 1080 }
 fn default_nested_width() -> u32 { 1920 }
@@ -259,6 +266,12 @@ fn default_format()      -> String { "ARGB8888".into() }
 fn default_asset_prefix() -> String { "file".into() }
 fn default_true()        -> bool { true }
 
+fn expand_path(s: &str) -> String {
+    shellexpand::full(s)
+        .map(|cow| cow.into_owned())
+        .unwrap_or_else(|_| s.to_owned())
+}
+
 impl Config {
     pub fn load() -> Result<Self> {
         // Try multiple locations in order of priority:
@@ -278,8 +291,13 @@ impl Config {
                 let text = std::fs::read_to_string(&path_opt)
                     .with_context(|| format!("reading config {path_opt:?}"))?;
 
-                return toml::from_str(&text)
-                    .with_context(|| format!("parsing config {path_opt:?}"));
+                let mut config: Self = toml::from_str(&text)
+                    .with_context(|| format!("parsing config {path_opt:?}"))?;
+                config.compositor.ipc_socket =
+                    expand_path(&config.compositor.ipc_socket);
+                config.compositor.portal_socket =
+                    expand_path(&config.compositor.portal_socket);
+                return Ok(config);
             }
         }
 
diff --git a/src/main.rs b/src/main.rs
index 5e8342e..465d077 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -778,10 +778,52 @@ fn run_drm(config: Config) -> Result<(), anyhow::Error> {
 
     let drm_device_fd = DrmDeviceFd::new(DeviceFd::from(drm_fd));
 
-    if let Err(e) = drm::Device::acquire_master_lock(&drm_device_fd) {
+    // Retry acquiring DRM master: on logind-managed sessions (e.g. Ly) the VT
+    // switch and master hand-off from logind may not be complete at the exact
+    // moment session.open() returns.  libseat's builtin backend logs "Unable to
+    // become DRM master, entering unprivileged mode" and returns the fd anyway;
+    // pumping the event loop lets session-activation events propagate so that
+    // the next drmSetMaster() attempt succeeds.
+    const DRM_MASTER_RETRY_MS: u64 = 100;
+    const DRM_MASTER_RETRY_ROUNDS: u32 = 30; // up to ~3 s
+    let mut last_master_err = None;
+    for round in 0..=DRM_MASTER_RETRY_ROUNDS {
+        match drm::Device::acquire_master_lock(&drm_device_fd) {
+            Ok(()) => {
+                if round > 0 {
+                    info!("DRM master acquired after {} retries", round);
+                }
+                last_master_err = None;
+                break;
+            }
+            Err(e) => {
+                let detail = e.to_string();
+                if round == 0 {
+                    warn!(
+                        gpu = %gpu_path.display(),
+                        "DRM master not yet available ({}); retrying up to {}×{}ms...",
+                        detail,
+                        DRM_MASTER_RETRY_ROUNDS,
+                        DRM_MASTER_RETRY_MS,
+                    );
+                }
+                last_master_err = Some(detail);
+                let _ = event_loop.dispatch(
+                    Some(Duration::from_millis(DRM_MASTER_RETRY_MS)),
+                    &mut pre_init,
+                );
+            }
+        }
+    }
+    if let Some(e) = last_master_err {
         return Err(anyhow::anyhow!(
-            "failed to become DRM master on {}: {e}. The GPU is likely in use by another active session/compositor. Switch to a free VT, stop the other session, or set compositor.drm_device to a free card.",
-            gpu_path.display()
+            "failed to become DRM master on {gpu}: {e}. \
+             The GPU is likely in use by another active session/compositor. \
+             Ensure wo is launched as the session compositor by a logind-aware \
+             display manager (e.g. Ly, greetd) with pam_systemd.so in its PAM \
+             config, or switch to a free VT first. \
+             If using seatd, add your user to the 'seat' group.",
+            gpu = gpu_path.display(),
         ));
     }