smoke: the greeter wrapper testifies at its own exit points

The journal shows the greeter mid-wgpu-shader-compile when the whole
chain dies silently — three seconds in, no panic, no niri line. The
wrapper knows which branch ends the session (compositor death with
its status, socket timeout, greeter exit with rc); each branch now
logs it, tagged kuma-greeter. The failure dump also reads the kernel
journal now: a compositor dying without a log line leaves a
traps/segfault/oom line there instead. Goldens re-blessed; suite
green.

Author: Letdown2491

scripts/smoke.sh

@@ -249,6 +249,9 @@ bad()  {
         # but exactly the verdict an SELinux-bound greeter leaves.
         guest 'journalctl -b --no-pager -t kuma-greeter | tail -40' || true
         guest 'journalctl -b --no-pager | grep -iE "avc.*denied|selinux" | tail -20' || true
+        # a compositor or GPU client dying without its own log line
+        # leaves a kernel line instead: traps/segfault, oom-kill
+        guest 'journalctl -k -b --no-pager | grep -iE "segfault|general protection|traps:|oom-kill|killed process" | tail -10' || true
         guest 'journalctl -b --no-pager | grep -iE "greetd|niri|noctalia|kuma-shell|kuma-greeter" | tail -30' || true
         guest 'journalctl -b --no-pager | grep -vE "sshd|logind|audit|session-[0-9]+" | tail -30' || true
         guest 'journalctl --user -b --no-pager | grep -vE "sshd|logind|audit|session-[0-9]+" | tail -30' || true

src/containerfile/blocks.rs

@@ -532,8 +532,13 @@ export XDG_CACHE_HOME=/var/lib/greetd/cache
 export RUST_LOG=debug
 exec 2> >(exec logger -t kuma-greeter)
 
+# The wrapper knows why the session ends: compositor death, socket
+# timeout, or greeter exit with its status. Say so — three laps of a
+# silent "greeter exited without creating a session" bought this.
+echo "wrapper: greetd started the session (pid $$)"
 niri -c /usr/share/kumaos/greeter-niri.kdl &
 niri_pid=$!
+started=$SECONDS
 cleanup() { kill "$niri_pid" 2>/dev/null; }
 trap cleanup EXIT
 
@@ -543,19 +548,29 @@ sock=""
 for _ in $(seq 1 100); do
   sock=$(ls "$XDG_RUNTIME_DIR"/wayland-? 2>/dev/null | head -1)
   [ -n "$sock" ] && break
-  kill -0 "$niri_pid" 2>/dev/null || exit 1
+  if ! kill -0 "$niri_pid" 2>/dev/null; then
+    wait "$niri_pid"
+    echo "wrapper: niri died after $((SECONDS - started))s (exit $?)"
+    exit 1
+  fi
   sleep 0.1
 done
-[ -n "$sock" ] || exit 1
+if [ -z "$sock" ]; then
+  echo "wrapper: no wayland socket after 10s, niri still alive"
+  exit 1
+fi
+echo "wrapper: wayland socket up after $((SECONDS - started))s"
 
 WAYLAND_DISPLAY=${sock##*/} /usr/bin/kuma-greeter
 rc=$?
+echo "wrapper: greeter exited rc=$rc after $((SECONDS - started))s"
 # the greeter only exits on success or crash: either way hand the
 # session back to greetd immediately, don't make it wait out its
 # 5-second patience on a compositor nobody is using
 cleanup
 trap - EXIT
 wait "$niri_pid" 2>/dev/null
+echo "wrapper: niri reaped (exit $?)"
 exit $rc
 "#;
 

src/containerfile/goldens/everything-on.manifest

@@ -49,7 +49,7 @@ kuma-fstab-sync 8d91559a751bb9871641d2295536dac4fca72da4ca6b66787f5765cc0f191021
 kuma-fstab-sync.service 9d865e627355d6a5abb8ca39d00e62c41ef3effffe1eb235caeb16691622925b
 kuma-greeter 001555c61143bba5fc71ab136eadf5444ac9e0189bf20cc7fca15a6eb0224e25
 kuma-greeter-check ba4ff3ab5f84f6e5623a73a5a1c6f1384522652536f797bcad7048b3514fba5a
-kuma-greeter-session ab78d697690a44ce4c1e2cff73a40be3a3e012361ce5ec84314b19f1f43b0357
+kuma-greeter-session 8d9a8035f3352e4f4a0348523c4984d4b3e97a0795dae42f7a028180b48ba8ce
 kuma-greeter-tmpfiles.conf ac57bb5086c057d537a424cd2d36924a739ef48e8b74b00baeb14bc4f8c4477e
 kuma-home-subvol b90db7dc4eabc2b9a95bdf90e7c93a432f6b818cb36c8135cde11138b39e2766
 kuma-home-subvol.service af9133fe3d2a930c432880a9937c71e8842e6d0fefbd75da065dc745240e4573

src/containerfile/goldens/niri.manifest

@@ -37,7 +37,7 @@ kuma-fstab-sync 8d91559a751bb9871641d2295536dac4fca72da4ca6b66787f5765cc0f191021
 kuma-fstab-sync.service 9d865e627355d6a5abb8ca39d00e62c41ef3effffe1eb235caeb16691622925b
 kuma-greeter 001555c61143bba5fc71ab136eadf5444ac9e0189bf20cc7fca15a6eb0224e25
 kuma-greeter-check ba4ff3ab5f84f6e5623a73a5a1c6f1384522652536f797bcad7048b3514fba5a
-kuma-greeter-session ab78d697690a44ce4c1e2cff73a40be3a3e012361ce5ec84314b19f1f43b0357
+kuma-greeter-session 8d9a8035f3352e4f4a0348523c4984d4b3e97a0795dae42f7a028180b48ba8ce
 kuma-greeter-tmpfiles.conf ac57bb5086c057d537a424cd2d36924a739ef48e8b74b00baeb14bc4f8c4477e
 kuma-home-subvol b90db7dc4eabc2b9a95bdf90e7c93a432f6b818cb36c8135cde11138b39e2766
 kuma-home-subvol.service af9133fe3d2a930c432880a9937c71e8842e6d0fefbd75da065dc745240e4573

src/containerfile/goldens/nostr.manifest

@@ -37,7 +37,7 @@ kuma-fstab-sync 8d91559a751bb9871641d2295536dac4fca72da4ca6b66787f5765cc0f191021
 kuma-fstab-sync.service 9d865e627355d6a5abb8ca39d00e62c41ef3effffe1eb235caeb16691622925b
 kuma-greeter 001555c61143bba5fc71ab136eadf5444ac9e0189bf20cc7fca15a6eb0224e25
 kuma-greeter-check ba4ff3ab5f84f6e5623a73a5a1c6f1384522652536f797bcad7048b3514fba5a
-kuma-greeter-session ab78d697690a44ce4c1e2cff73a40be3a3e012361ce5ec84314b19f1f43b0357
+kuma-greeter-session 8d9a8035f3352e4f4a0348523c4984d4b3e97a0795dae42f7a028180b48ba8ce
 kuma-greeter-tmpfiles.conf ac57bb5086c057d537a424cd2d36924a739ef48e8b74b00baeb14bc4f8c4477e
 kuma-home-subvol b90db7dc4eabc2b9a95bdf90e7c93a432f6b818cb36c8135cde11138b39e2766
 kuma-home-subvol.service af9133fe3d2a930c432880a9937c71e8842e6d0fefbd75da065dc745240e4573