Enhancement/efi shell interface

uefi-test-runner/src/proto/shell.rs

@@ -1,13 +1,75 @@
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
-use uefi::boot;
+use uefi::boot::ScopedProtocol;
 use uefi::proto::shell::Shell;
+use uefi::{boot, cstr16};
+
+/// Test `var()`, `vars()`, and `set_var()`
+pub fn test_var(shell: &ScopedProtocol<Shell>) {
+    /* Test retrieving list of environment variable names */
+    let mut cur_env_vec = shell.vars();
+    assert_eq!(cur_env_vec.next().unwrap().0, cstr16!("path"));
+    // check pre-defined shell variables; see UEFI Shell spec
+    assert_eq!(cur_env_vec.next().unwrap().0, cstr16!("nonesting"));
+    let cur_env_vec = shell.vars();
+    let default_len = cur_env_vec.count();
+
+    /* Test setting and getting a specific environment variable */
+    let cur_env_vec = shell.vars();
+    let test_var = cstr16!("test_var");
+    let test_val = cstr16!("test_val");
+    assert!(shell.var(test_var).is_none());
+    let status = shell.set_var(test_var, test_val, false);
+    assert!(status.is_ok());
+    let cur_env_str = shell
+        .var(test_var)
+        .expect("Could not get environment variable");
+    assert_eq!(cur_env_str, test_val);
+
+    let mut found_var = false;
+    for (env_var, _) in cur_env_vec {
+        if env_var == test_var {
+            found_var = true;
+        }
+    }
+    assert!(!found_var);
+    let cur_env_vec = shell.vars();
+    let mut found_var = false;
+    for (env_var, _) in cur_env_vec {
+        if env_var == test_var {
+            found_var = true;
+        }
+    }
+    assert!(found_var);
+
+    let cur_env_vec = shell.vars();
+    assert_eq!(cur_env_vec.count(), default_len + 1);
+
+    /* Test deleting environment variable */
+    let test_val = cstr16!("");
+    let status = shell.set_var(test_var, test_val, false);
+    assert!(status.is_ok());
+    assert!(shell.var(test_var).is_none());
+
+    let cur_env_vec = shell.vars();
+    let mut found_var = false;
+    for (env_var, _) in cur_env_vec {
+        if env_var == test_var {
+            found_var = true;
+        }
+    }
+    assert!(!found_var);
+    let cur_env_vec = shell.vars();
+    assert_eq!(cur_env_vec.count(), default_len);
+}
 
 pub fn test() {
     info!("Running shell protocol tests");
 
     let handle = boot::get_handle_for_protocol::<Shell>().expect("No Shell handles");
 
-    let mut _shell =
+    let shell =
         boot::open_protocol_exclusive::<Shell>(handle).expect("Failed to open Shell protocol");
+
+    test_var(&shell);
 }

uefi/src/proto/shell/mod.rs

@@ -2,12 +2,209 @@
 
 //! EFI Shell Protocol v2.2
 
-use crate::proto::unsafe_protocol;
+use uefi_macros::unsafe_protocol;
 
-pub use uefi_raw::protocol::shell::ShellProtocol;
+use core::marker::PhantomData;
+use core::ptr;
+
+use uefi_raw::protocol::shell::ShellProtocol;
+
+use crate::{CStr16, Char16, Result, StatusExt};
 
 /// Shell Protocol
 #[derive(Debug)]
 #[repr(transparent)]
-#[unsafe_protocol(uefi_raw::protocol::shell::ShellProtocol::GUID)]
-pub struct Shell(uefi_raw::protocol::shell::ShellProtocol);
+#[unsafe_protocol(ShellProtocol::GUID)]
+pub struct Shell(ShellProtocol);
+
+/// Trait for implementing the var function
+pub trait ShellVar {
+    /// Gets the value of the specified environment variable
+    fn var(&self, name: &CStr16) -> Option<&CStr16>;
+}
+
+/// Iterator over the names of environmental variables obtained from the Shell protocol.
+#[derive(Debug)]
+pub struct Vars<'a, T: ShellVar> {
+    /// Char16 containing names of environment variables
+    names: *const Char16,
+    /// Reference to Shell Protocol
+    protocol: *const T,
+    /// Placeholder to attach a lifetime to `Vars`
+    placeholder: PhantomData<&'a CStr16>,
+}
+
+impl<'a, T: ShellVar + 'a> Iterator for Vars<'a, T> {
+    type Item = (&'a CStr16, Option<&'a CStr16>);
+    // We iterate a list of NUL terminated CStr16s.
+    // The list is terminated with a double NUL.
+    fn next(&mut self) -> Option<Self::Item> {
+        let s = unsafe { CStr16::from_ptr(self.names) };
+        if s.is_empty() {
+            None
+        } else {
+            self.names = unsafe { self.names.add(s.num_chars() + 1) };
+            Some((s, unsafe { self.protocol.as_ref().unwrap().var(s) }))
+        }
+    }
+}
+
+impl ShellVar for Shell {
+    /// Gets the value of the specified environment variable
+    fn var(&self, name: &CStr16) -> Option<&CStr16> {
+        self.var(name)
+    }
+}
+
+impl Shell {
+    /// Gets the value of the specified environment variable
+    ///
+    /// # Arguments
+    ///
+    /// * `name` - The environment variable name of which to retrieve the
+    ///   value.
+    ///
+    /// # Returns
+    ///
+    /// * `Some(<env_value>)` - &CStr16 containing the value of the
+    ///   environment variable
+    /// * `None` - If environment variable does not exist
+    #[must_use]
+    pub fn var(&self, name: &CStr16) -> Option<&CStr16> {
+        let name_ptr: *const Char16 = name.as_ptr();
+        let var_val = unsafe { (self.0.get_env)(name_ptr.cast()) };
+        if var_val.is_null() {
+            None
+        } else {
+            unsafe { Some(CStr16::from_ptr(var_val.cast())) }
+        }
+    }
+
+    /// Gets an iterator over the names of all environment variables
+    #[must_use]
+    pub fn vars(&self) -> Vars<'_, Self> {
+        let env_ptr = unsafe { (self.0.get_env)(ptr::null()) };
+        Vars {
+            names: env_ptr.cast::<Char16>(),
+            protocol: self,
+            placeholder: PhantomData,
+        }
+    }
+
+    /// Sets the environment variable
+    ///
+    /// # Arguments
+    ///
+    /// * `name` - The environment variable for which to set the value
+    /// * `value` - The new value of the environment variable
+    /// * `volatile` - Indicates whether the variable is volatile or
+    ///   not
+    ///
+    /// # Returns
+    ///
+    /// * `Status::SUCCESS` - The variable was successfully set
+    pub fn set_var(&self, name: &CStr16, value: &CStr16, volatile: bool) -> Result {
+        let name_ptr: *const Char16 = name.as_ptr();
+        let value_ptr: *const Char16 = value.as_ptr();
+        unsafe { (self.0.set_env)(name_ptr.cast(), value_ptr.cast(), volatile) }.to_result()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use alloc::collections::BTreeMap;
+    use alloc::vec::Vec;
+    use uefi::cstr16;
+
+    struct ShellMock<'a> {
+        inner: BTreeMap<&'a CStr16, &'a CStr16>,
+    }
+
+    impl<'a> ShellMock<'a> {
+        fn new(names: Vec<&'a CStr16>, values: Vec<&'a CStr16>) -> ShellMock<'a> {
+            let mut inner_map = BTreeMap::new();
+            for (name, val) in names.iter().zip(values.iter()) {
+                inner_map.insert(*name, *val);
+            }
+            ShellMock { inner: inner_map }
+        }
+    }
+    impl<'a> ShellVar for ShellMock<'a> {
+        fn var(&self, name: &CStr16) -> Option<&CStr16> {
+            if let Some(val) = self.inner.get(name) {
+                Some(*val)
+            } else {
+                None
+            }
+        }
+    }
+
+    /// Testing Vars struct
+    #[test]
+    fn test_vars() {
+        // Empty Vars
+        let mut vars_mock = Vec::<u16>::new();
+        vars_mock.push(0);
+        vars_mock.push(0);
+        let mut vars = Vars {
+            names: vars_mock.as_ptr().cast(),
+            protocol: &ShellMock::new(Vec::new(), Vec::new()),
+            placeholder: PhantomData,
+        };
+
+        assert!(vars.next().is_none());
+
+        // One environment variable in Vars
+        let mut vars_mock = Vec::<u16>::new();
+        vars_mock.push(b'f' as u16);
+        vars_mock.push(b'o' as u16);
+        vars_mock.push(b'o' as u16);
+        vars_mock.push(0);
+        vars_mock.push(0);
+        let vars = Vars {
+            names: vars_mock.as_ptr().cast(),
+            protocol: &ShellMock::new(Vec::from([cstr16!("foo")]), Vec::from([cstr16!("value")])),
+            placeholder: PhantomData,
+        };
+        assert_eq!(
+            vars.collect::<Vec<_>>(),
+            Vec::from([(cstr16!("foo"), Some(cstr16!("value")))])
+        );
+
+        // Multiple environment variables in Vars
+        let mut vars_mock = Vec::<u16>::new();
+        vars_mock.push(b'f' as u16);
+        vars_mock.push(b'o' as u16);
+        vars_mock.push(b'o' as u16);
+        vars_mock.push(b'1' as u16);
+        vars_mock.push(0);
+        vars_mock.push(b'b' as u16);
+        vars_mock.push(b'a' as u16);
+        vars_mock.push(b'r' as u16);
+        vars_mock.push(0);
+        vars_mock.push(b'b' as u16);
+        vars_mock.push(b'a' as u16);
+        vars_mock.push(b'z' as u16);
+        vars_mock.push(b'2' as u16);
+        vars_mock.push(0);
+        vars_mock.push(0);
+
+        let vars = Vars {
+            names: vars_mock.as_ptr().cast(),
+            protocol: &ShellMock::new(
+                Vec::from([cstr16!("foo1"), cstr16!("bar"), cstr16!("baz2")]),
+                Vec::from([cstr16!("value"), cstr16!("one"), cstr16!("two")]),
+            ),
+            placeholder: PhantomData,
+        };
+        assert_eq!(
+            vars.collect::<Vec<_>>(),
+            Vec::from([
+                (cstr16!("foo1"), Some(cstr16!("value"))),
+                (cstr16!("bar"), Some(cstr16!("one"))),
+                (cstr16!("baz2"), Some(cstr16!("two")))
+            ])
+        );
+    }
+}