allow device matching by udev properties

src/udev.rs

@@ -63,3 +63,148 @@ pub fn get_devices(class: &str) -> Result<Vec<Device>> {
 
     Ok(devices)
 }
+
+pub async fn all() -> Result<Devs> {
+    let output = tokio::process::Command::new("udevadm")
+        .args(["info", "-e"])
+        .stderr(std::process::Stdio::inherit())
+        .output()
+        .await?;
+
+    if !output.status.success() {
+        return Err(eyre::format_err!("udevadm failed: {}", output.status));
+    }
+
+    Ok(Devs {
+        data: unsafe { String::from_utf8_unchecked(output.stdout) },
+    })
+}
+
+pub async fn by_path(path: &str) -> Result<Devs> {
+    let output = tokio::process::Command::new("udevadm")
+        .args(["info", path])
+        .stderr(std::process::Stdio::inherit())
+        .output()
+        .await?;
+
+    if !output.status.success() {
+        return Err(eyre::format_err!("udevadm failed: {}", output.status));
+    }
+
+    Ok(Devs {
+        data: unsafe { String::from_utf8_unchecked(output.stdout) },
+    })
+}
+
+pub struct Devs {
+    data: String,
+}
+
+impl<'t> Devs {
+    pub fn iter(&'t self) -> impl Iterator<Item = Dev<'t>> {
+        self.data
+            .split("\n\n")
+            .filter(|s| !s.is_empty())
+            .map(|s| Dev(s))
+    }
+
+    pub fn of_subsystem(&'t self, subsystem: &str) -> impl Iterator<Item = Dev<'t>> {
+        self.iter().filter(|dev| dev.subsystem() == Some(subsystem))
+    }
+}
+
+pub struct Dev<'t>(&'t str);
+
+impl<'t> Dev<'t> {
+    pub fn raw(&self) -> &str {
+        self.0
+    }
+
+    // alpine's udev prefixes we've seen:
+    // - P: Device path in /sys/
+    // - N: Kernel device node name
+    // - S: Device node symlink
+    // - L: Device node symlink priority [ignored]
+    // - E: Device property
+
+    fn by_prefix(&self, prefix: &'static str) -> impl Iterator<Item = &str> {
+        self.0.lines().filter_map(move |l| l.strip_prefix(prefix))
+    }
+
+    /// Device path in /sys/
+    pub fn path(&self) -> Option<&str> {
+        self.by_prefix("P: ").next()
+    }
+
+    /// Kernel device node name
+    pub fn name(&self) -> Option<&str> {
+        self.by_prefix("N: ").next()
+    }
+
+    /// Device node symlinks
+    pub fn symlinks(&self) -> Vec<&str> {
+        self.by_prefix("S: ").collect()
+    }
+
+    /// Device properties
+    pub fn properties(&self) -> impl Iterator<Item = (&str, &str)> {
+        self.by_prefix("E: ").filter_map(|s| s.split_once("="))
+    }
+
+    /// Device property
+    pub fn property(&self, name: &str) -> Option<&str> {
+        self.properties()
+            .filter_map(|(n, v)| (n == name).then_some(v))
+            .next()
+    }
+
+    /// Device subsystem
+    pub fn subsystem(&self) -> Option<&str> {
+        self.property("SUBSYSTEM")
+    }
+}
+
+pub enum Filter {
+    Has(String),
+    Eq(String, String),
+    Glob(String, glob::Pattern),
+    And(Vec<Filter>),
+    Or(Vec<Filter>),
+    Not(Box<Filter>),
+    False,
+}
+
+impl<'t> Filter {
+    pub fn matches(&self, dev: &Dev) -> bool {
+        match self {
+            Self::False => false,
+            Self::Has(k) => dev.property(k).is_some(),
+            Self::Eq(k, v) => dev.properties().any(|kv| kv == (k, v)),
+            Self::Glob(k, pattern) => dev
+                .properties()
+                .any(|(pk, pv)| pk == k && pattern.matches(pv)),
+            Self::And(ops) => ops.iter().all(|op| op.matches(dev)),
+            Self::Or(ops) => ops.iter().any(|op| op.matches(dev)),
+            Self::Not(op) => !op.matches(dev),
+        }
+    }
+}
+
+impl<'t> Into<Filter> for dkl::bootstrap::UdevFilter {
+    fn into(self) -> Filter {
+        match self {
+            Self::Has(p) => Filter::Has(p),
+            Self::Eq(p, v) => Filter::Eq(p, v),
+            Self::Glob(p, pattern) => match glob::Pattern::new(&pattern) {
+                Ok(pattern) => Filter::Glob(p, pattern),
+                Err(e) => {
+                    warn!("pattern {pattern:?} will never match: {e}");
+                    Filter::False
+                }
+            },
+            Self::And(ops) => Filter::And(ops.into_iter().map(Self::into).collect()),
+            Self::Or(ops) => Filter::Or(ops.into_iter().map(Self::into).collect()),
+            Self::Not(op) => Filter::Not(Box::new((*op).into())),
+        }
+    }
+}