ksud: fix issues found by clippy (#167)

These issues are mostly found by `cargo clippy -- -W clippy::pedantic`.

userspace/ksud/src/mount.rs

@@ -1,23 +1,21 @@
 use anyhow::Result;
 
-#[cfg(target_os = "android")]
+#[cfg(unix)]
 use anyhow::{Context, Ok};
-#[cfg(target_os = "android")]
+#[cfg(unix)]
 use retry::delay::NoDelay;
-#[cfg(target_os = "android")]
+#[cfg(unix)]
 use sys_mount::{unmount, FilesystemType, Mount, MountFlags, Unmount, UnmountFlags};
 
-#[allow(dead_code)]
 pub struct AutoMountExt4 {
     mnt: String,
-    #[cfg(target_os = "android")]
+    #[cfg(unix)]
     mount: Option<Mount>,
     auto_umount: bool,
 }
 
-#[allow(dead_code)]
 impl AutoMountExt4 {
-    #[cfg(target_os = "android")]
+    #[cfg(unix)]
     pub fn try_new(src: &str, mnt: &str, auto_umount: bool) -> Result<Self> {
         let result = Mount::builder()
             .fstype(FilesystemType::from("ext4"))
@@ -27,11 +25,11 @@ impl AutoMountExt4 {
                 Ok(Self {
                     mnt: mnt.to_string(),
                     mount: Some(mount),
-                    auto_umount
+                    auto_umount,
                 })
             });
         if let Err(e) = result {
-            println!("- Mount failed: {}, retry with system mount", e);
+            println!("- Mount failed: {e}, retry with system mount");
             let result = std::process::Command::new("mount")
                 .arg("-t")
                 .arg("ext4")
@@ -46,7 +44,7 @@ impl AutoMountExt4 {
                 Ok(Self {
                     mnt: mnt.to_string(),
                     mount: None,
-                    auto_umount
+                    auto_umount,
                 })
             }
         } else {
@@ -54,41 +52,45 @@ impl AutoMountExt4 {
         }
     }
 
-    #[cfg(not(target_os = "android"))]
+    #[cfg(not(unix))]
     pub fn try_new(_src: &str, _mnt: &str, _auto_umount: bool) -> Result<Self> {
         unimplemented!()
     }
 
-    #[cfg(target_os = "android")]
+    #[cfg(unix)]
     pub fn umount(&self) -> Result<()> {
-        match self.mount {
-            Some(ref mount) => mount
+        if let Some(ref mount) = self.mount {
+            mount
                 .unmount(UnmountFlags::empty())
-                .map_err(|e| anyhow::anyhow!(e)),
-            None => {
-                let result = std::process::Command::new("umount").arg(&self.mnt).status();
-                if let Err(e) = result {
-                    Err(anyhow::anyhow!("umount: {} failed: {e}", self.mnt))
-                } else {
-                    Ok(())
-                }
+                .map_err(|e| anyhow::anyhow!(e))
+        } else {
+            let result = std::process::Command::new("umount").arg(&self.mnt).status();
+            if let Err(e) = result {
+                Err(anyhow::anyhow!("umount: {} failed: {e}", self.mnt))
+            } else {
+                Ok(())
             }
         }
     }
 }
 
-#[cfg(target_os = "android")]
+#[cfg(unix)]
 impl Drop for AutoMountExt4 {
     fn drop(&mut self) {
-        log::info!("AutoMountExt4 drop: {}, auto_umount: {}", self.mnt, self.auto_umount);
+        log::info!(
+            "AutoMountExt4 drop: {}, auto_umount: {}",
+            self.mnt,
+            self.auto_umount
+        );
         if self.auto_umount {
             let _ = self.umount();
         }
     }
 }
 
-#[cfg(target_os = "android")]
-fn do_mount_image(src: &str, target: &str, autodrop: bool) -> Result<()> {
+#[allow(dead_code)]
+#[cfg(unix)]
+fn mount_image(src: &str, target: &str, autodrop: bool) -> Result<()> {
     if autodrop {
         Mount::builder()
             .fstype(FilesystemType::from("ext4"))
@@ -103,23 +105,24 @@ fn do_mount_image(src: &str, target: &str, autodrop: bool) -> Result<()> {
     Ok(())
 }
 
-#[cfg(target_os = "android")]
+#[allow(dead_code)]
+#[cfg(unix)]
 pub fn mount_ext4(src: &str, target: &str, autodrop: bool) -> Result<()> {
     // umount target first.
     let _ = umount_dir(target);
-    let result = retry::retry(NoDelay.take(3), || do_mount_image(src, target, autodrop));
+    let result = retry::retry(NoDelay.take(3), || mount_image(src, target, autodrop));
     result
         .map_err(|e| anyhow::anyhow!("mount partition: {src} -> {target} failed: {e}"))
         .map(|_| ())
 }
 
-#[cfg(target_os = "android")]
+#[cfg(unix)]
 pub fn umount_dir(src: &str) -> Result<()> {
     unmount(src, UnmountFlags::empty()).with_context(|| format!("Failed to umount {src}"))?;
     Ok(())
 }
 
-#[cfg(target_os = "android")]
+#[cfg(unix)]
 pub fn mount_overlay(lowerdir: &str, mnt: &str) -> Result<()> {
     Mount::builder()
         .fstype(FilesystemType::from("overlay"))
@@ -130,17 +133,17 @@ pub fn mount_overlay(lowerdir: &str, mnt: &str) -> Result<()> {
         .map_err(|e| anyhow::anyhow!("mount partition: {mnt} overlay failed: {e}"))
 }
 
-#[cfg(not(target_os = "android"))]
+#[cfg(not(unix))]
 pub fn mount_ext4(_src: &str, _target: &str, _autodrop: bool) -> Result<()> {
     unimplemented!()
 }
 
-#[cfg(not(target_os = "android"))]
+#[cfg(not(unix))]
 pub fn umount_dir(_src: &str) -> Result<()> {
     unimplemented!()
 }
 
-#[cfg(not(target_os = "android"))]
+#[cfg(not(unix))]
 pub fn mount_overlay(_lowerdir: &str, _mnt: &str) -> Result<()> {
     unimplemented!()
 }