Improve list() error handling

Author: nvinson

src/bin/efivar.rs

@@ -109,13 +109,32 @@ fn create_parser() -> clap::Command {
         );
 }
 
-fn list_variables(parser_args: clap::ArgMatches) -> ExitCode {
-    let mut efi_variables: efivar::efivarfs::EfiVariables = Default::default();
+fn list_variables(_parser_args: clap::ArgMatches) -> ExitCode {
+    let mut efivar_fs_variables: efivar::efivarfs::EfiVariables = Default::default();
 
-    for v in efi_variables.list() {
-        println!("{}", v);
+    match efivar_fs_variables.list() {
+        Ok(variables) => {
+            for v in variables {
+                println!("{}", v);
+            }
+            return std::process::ExitCode::from(0);
+        },
+        Err(_) => {
+            let mut efivar_variables: efivar::efivar::EfiVariables = Default::default();
+            match efivar_variables.list() {
+                Ok(variables) => {
+                    for v in variables {
+                        println!("{}", v);
+                    }
+                    return std::process::ExitCode::from(0);
+                },
+                Err(e) => {
+                    eprintln!("Failed to access EFI variables: {}", e);
+                    return std::process::ExitCode::from(1);
+                }
+            }
+        }
     }
-    return std::process::ExitCode::from(0);
 }
 
 fn print_variable(parser_args: clap::ArgMatches, print_mode: efivar::types::PrintMode) -> ExitCode {
@@ -175,6 +194,6 @@ fn main() -> ExitCode {
         return export_variable(matches);
     } else {
         parser.write_help(&mut io::stderr()).ignore();
-        return std::process::ExitCode::from(22 /* EINVAL */);
+        return std::process::ExitCode::from(1);
     }
 }

src/lib/efivar/efivar/efi_variables.rs

@@ -1,4 +1,5 @@
 use crate::efivarfs;
+use std::io;
 use std::path::PathBuf;
 
 const EFIVARS_PATH: &'static str = "/sys/firmware/efi/vars";
@@ -21,7 +22,7 @@ impl EfiVariables {
         return self;
     }
 
-    pub fn list(&self) -> efivarfs::EfiVariablesNameIter {
+    pub fn list(&self) -> io::Result<efivarfs::EfiVariablesNameIter> {
         let mut e: efivarfs::EfiVariables = Default::default();
         e.set_path(self.path.clone());
         return e.list();

src/lib/efivar/efivarfs/efi_variables.rs

@@ -1,6 +1,7 @@
 use crate::types::EfiGuid;
 use std::fs::{self, ReadDir};
 use std::path::PathBuf;
+use std::io;
 
 const EFIVARFS_PATH: &'static str = "/sys/firmware/efi/efivars";
 
@@ -82,18 +83,25 @@ impl EfiVariables {
         return self;
     }
 
-    pub fn list(&mut self) -> EfiVariablesNameIter {
-        if self.path.is_dir() {
-            let iter = fs::read_dir(&self.path);
-            return EfiVariablesNameIter {
-                dir_entry_iter: match iter {
-                    Ok(i) => Some(i),
-                    Err(_) => None,
-                },
-            };
-        }
-        return EfiVariablesNameIter {
-            dir_entry_iter: None,
+    pub fn list(&mut self) -> io::Result<EfiVariablesNameIter> {
+        return match fs::metadata(self.path.as_path()) {
+            Ok(m) => {
+                if m.is_dir() {
+                    let iter = fs::read_dir(&self.path);
+                    return Ok(EfiVariablesNameIter {
+                        dir_entry_iter: match iter {
+                            Ok(i) => Some(i),
+                            Err(_) => None,
+                        },
+                    });
+                }
+                /*
+                 * Should return NotADirectory, but Rust doesn't support that, so return NotFound
+                 * instead.
+                 */
+                return Err(io::ErrorKind::NotFound.into());
+            },
+            Err(e) => Err(e),
         };
     }
 }