fix(boot): clean up bare/mini boot warnings and errors

- init: add condition_path_exists so optional-daemon units (dbus, seatd,
  thermald, evdevd) are silently skipped when their binary is absent in a
  minimal image, instead of emitting [FAILED] 'No such file or directory' on
  the bare target. Boot-critical units omit the field and still hard-fail.
- ahcid: an empty ATAPI/optical drive (QEMU's default DVD-ROM, most bare-metal
  optical bays) failed READ CAPACITY and logged 4 ERROR lines every boot;
  register it with a zero block count as a normal no-media state and drop the
  HBA register dump to debug level.
- netstack: a machine with no NIC (bare, or an unsupported NIC) logged an ERROR
  and exited non-zero; treat 'no network adapter' as a normal idle state
  (info + clean exit).
- dhcpd: cut the socket timeout 30s -> 8s so the network stage fails fast when
  no DHCP server answers instead of stalling boot.

dhcpd/src/main.rs

@@ -122,8 +122,13 @@ fn dhcp(iface: &str, verbose: bool) -> Result<(), String> {
 
     let socket = try_fmt!(UdpSocket::bind(("0.0.0.0", 68)), "failed to bind udp");
     try_fmt!(socket.connect(SocketAddr::from(([255, 255, 255, 255], 67))), "failed to connect");
-    try_fmt!(socket.set_read_timeout(Some(Duration::new(30, 0))), "failed to set read timeout");
+    // 8s (was 30s): a DHCP server that is present answers a DISCOVER in well
-    try_fmt!(socket.set_write_timeout(Some(Duration::new(30, 0))), "failed to set write timeout");
+    // under a second, so a long read timeout only serves to stall boot when no
+    // server responds (e.g. QEMU user-net where the limited broadcast is not
+    // routed, or a link with no DHCP). Failing fast keeps the network stage off
+    // the critical path to login instead of hanging the boot for ~30s+.
+    try_fmt!(socket.set_read_timeout(Some(Duration::new(8, 0))), "failed to set read timeout");
+    try_fmt!(socket.set_write_timeout(Some(Duration::new(8, 0))), "failed to set write timeout");
 
     let mut subnet_option: Option<[u8; 4]> = None;
     let mut router_option: Option<[u8; 4]> = None;

drivers/storage/ahcid/src/ahci/disk_atapi.rs

@@ -48,11 +48,25 @@ impl DiskATAPI {
 
         let mut cmd = [0; 16];
         cmd[0] = SCSI_READ_CAPACITY;
-        port.atapi_dma(&cmd, 8, &mut clb, &mut ctbas, &mut buf)?;
 
-        // Instead of a count, contains number of last LBA, so add 1
+        // An ATAPI drive with no media inserted (an empty optical drive — the
-        let blk_count = BigEndian::read_u32(&buf[0..4]) + 1;
+        // default state of QEMU's DVD-ROM and of most real machines that have an
-        let blk_size = BigEndian::read_u32(&buf[4..8]);
+        // optical bay at all) fails READ CAPACITY with a check-condition / I/O
+        // error. That is a normal, expected condition, NOT a driver fault, so
+        // register the drive with a zero block count instead of failing
+        // enumeration and logging a scary ERROR on every boot. It becomes
+        // usable once media is present and the capacity is re-read.
+        let (blk_count, blk_size) =
+            match port.atapi_dma(&cmd, 8, &mut clb, &mut ctbas, &mut buf) {
+                Ok(_) => {
+                    // Instead of a count, contains number of last LBA, so add 1
+                    (BigEndian::read_u32(&buf[0..4]) + 1, BigEndian::read_u32(&buf[4..8]))
+                }
+                Err(_) => {
+                    log::info!("ahcid: ATAPI port {}: no media present (empty drive)", id);
+                    (0, 2048)
+                }
+            };
 
         Ok(DiskATAPI {
             id,

drivers/storage/ahcid/src/ahci/hba.rs

@@ -448,12 +448,17 @@ impl HbaPort {
                 self.fbs.read(),
             );
 
-            error!("IS {:X} IE {:X} CMD {:X} TFD {:X}", is, ie, cmd, tfd);
+            // Diagnostic register dump, emitted at debug level: a port error is
-            error!(
+            // an expected, recoverable condition (e.g. READ CAPACITY on an empty
+            // ATAPI/optical drive) and the caller decides whether it is fatal and
+            // logs an appropriate user-facing message. Keeping this at `error!`
+            // spammed three scary lines on every boot for an empty CD-ROM.
+            debug!("IS {:X} IE {:X} CMD {:X} TFD {:X}", is, ie, cmd, tfd);
+            debug!(
                 "SSTS {:X} SCTL {:X} SERR {:X} SACT {:X}",
                 ssts, sctl, serr, sact
             );
-            error!("CI {:X} SNTF {:X} FBS {:X}", ci, sntf, fbs);
+            debug!("CI {:X} SNTF {:X} FBS {:X}", ci, sntf, fbs);
 
             self.is.write(u32::MAX);
             Err(Error::new(EIO))

init.d/10_evdevd.service

@@ -1,4 +1,5 @@
 [unit]
+condition_path_exists = ["/usr/bin/evdevd"]
 description = "Evdev input daemon"
 requires_weak = [
     "12_boot-late.target",

init.d/12_dbus.service

@@ -1,4 +1,5 @@
 [unit]
+condition_path_exists = ["/usr/bin/dbus-daemon"]
 description = "D-Bus system bus"
 requires_weak = ["12_boot_late.target", "00_ipcd.service"]
 

init.d/13_seatd.service

@@ -1,4 +1,5 @@
 [unit]
+condition_path_exists = ["/usr/bin/seatd"]
 description = "seatd seat management"
 requires_weak = ["12_dbus.service"]
 

init.d/30_thermald.service

@@ -1,4 +1,5 @@
 [unit]
+condition_path_exists = ["/usr/bin/thermald"]
 description = "CPU Thermal Monitor"
 requires_weak = ["00_base.target"]
 

init/src/unit.rs

@@ -125,6 +125,13 @@ pub struct UnitInfo {
     pub condition_architecture: Option<Vec<String>>,
     // FIXME replace this with hwd reading from the devicetree
     pub condition_board: Option<Vec<String>>,
+    /// Only start this unit if every listed path exists. Used for optional
+    /// daemons whose binary may be absent in a minimal image (e.g. dbus-daemon,
+    /// seatd, thermald, evdevd on the bare target). When the binary is not
+    /// installed the unit is silently skipped instead of producing a spurious
+    /// `[ FAILED ]` "No such file or directory" line — real boot-critical units
+    /// omit this field and still hard-fail if their binary is missing.
+    pub condition_path_exists: Option<Vec<String>>,
 }
 
 fn true_bool() -> bool {
@@ -190,6 +197,7 @@ impl Unit {
                     requires_weak: script.1,
                     condition_architecture: None,
                     condition_board: None,
+                    condition_path_exists: None,
                 },
                 kind: UnitKind::LegacyScript { script: script.0 },
             });
@@ -246,6 +254,15 @@ impl Unit {
             }
         }
 
+        if let Some(condition_path_exists) = &self.info.condition_path_exists {
+            if !condition_path_exists
+                .iter()
+                .all(|path| std::path::Path::new(path).exists())
+            {
+                return false;
+            }
+        }
+
         true
     }
 }

netstack/src/main.rs

@@ -2,7 +2,7 @@
 extern crate log;
 use std::process;
 
-use anyhow::{anyhow, bail, Context, Result};
+use anyhow::{anyhow, Context, Result};
 use event::{EventFlags, EventQueue};
 use libredox::flag::{O_NONBLOCK, O_RDWR};
 use libredox::Fd;
@@ -36,7 +36,12 @@ fn get_all_network_adapters() -> Result<Vec<String>> {
     }
 
     if adapters.is_empty() {
-        bail!("no network adapter found");
+        // No NIC present is a normal state on a diskless/headless/bare machine,
+        // or simply before an unsupported NIC's driver attaches. Report it as
+        // info and let the caller exit cleanly instead of emitting a spurious
+        // ERROR + non-zero exit on every boot of a NIC-less system.
+        info!("no network adapter found; network stack idle");
+        return Ok(adapters);
     }
     info!("Found {} network adapter(s): {:?}", adapters.len(), adapters);
     Ok(adapters)
@@ -44,6 +49,10 @@ fn get_all_network_adapters() -> Result<Vec<String>> {
 
 fn run(daemon: daemon::Daemon) -> Result<()> {
     let adapters = get_all_network_adapters()?;
+    if adapters.is_empty() {
+        // Nothing to service; exit cleanly (see get_all_network_adapters).
+        return Ok(());
+    }
     trace!("found {} network adapter(s)", adapters.len());
 
     let mut network_fds = Vec::new();