1 files changed, 83 insertions, 8 deletions

diff --git a/rust/kernel/task.rs b/rust/kernel/task.rs
index 55dff7e088bf..1a36a9f19368 100644
--- a/rust/kernel/task.rs
+++ b/rust/kernel/task.rs
@@ -4,10 +4,13 @@
 //!
 //! C header: [`include/linux/sched.h`](srctree/include/linux/sched.h).
 
-use crate::types::Opaque;
+use crate::{
+    bindings,
+    types::{NotThreadSafe, Opaque},
+};
 use core::{
+    cmp::{Eq, PartialEq},
     ffi::{c_int, c_long, c_uint},
-    marker::PhantomData,
     ops::Deref,
     ptr,
 };
@@ -94,7 +97,22 @@ unsafe impl Sync for Task {}
 /// The type of process identifiers (PIDs).
 type Pid = bindings::pid_t;
 
+/// The type of user identifiers (UIDs).
+#[derive(Copy, Clone)]
+pub struct Kuid {
+    kuid: bindings::kuid_t,
+}
+
 impl Task {
+    /// Returns a raw pointer to the current task.
+    ///
+    /// It is up to the user to use the pointer correctly.
+    #[inline]
+    pub fn current_raw() -> *mut bindings::task_struct {
+        // SAFETY: Getting the current pointer is always safe.
+        unsafe { bindings::get_current() }
+    }
+
     /// Returns a task reference for the currently executing task/thread.
     ///
     /// The recommended way to get the current task/thread is to use the
@@ -106,7 +124,7 @@ impl Task {
     pub unsafe fn current() -> impl Deref<Target = Task> {
         struct TaskRef<'a> {
             task: &'a Task,
-            _not_send: PhantomData<*mut ()>,
+            _not_send: NotThreadSafe,
         }
 
         impl Deref for TaskRef<'_> {
@@ -117,15 +135,13 @@ impl Task {
             }
         }
 
-        // SAFETY: Just an FFI call with no additional safety requirements.
-        let ptr = unsafe { bindings::get_current() };
-
+        let current = Task::current_raw();
         TaskRef {
             // SAFETY: If the current thread is still running, the current task is valid. Given
             // that `TaskRef` is not `Send`, we know it cannot be transferred to another thread
             // (where it could potentially outlive the caller).
-            task: unsafe { &*ptr.cast() },
-            _not_send: PhantomData,
+            task: unsafe { &*current.cast() },
+            _not_send: NotThreadSafe,
         }
     }
 
@@ -148,12 +164,31 @@ impl Task {
         unsafe { *ptr::addr_of!((*self.0.get()).pid) }
     }
 
+    /// Returns the UID of the given task.
+    pub fn uid(&self) -> Kuid {
+        // SAFETY: By the type invariant, we know that `self.0` is valid.
+        Kuid::from_raw(unsafe { bindings::task_uid(self.0.get()) })
+    }
+
+    /// Returns the effective UID of the given task.
+    pub fn euid(&self) -> Kuid {
+        // SAFETY: By the type invariant, we know that `self.0` is valid.
+        Kuid::from_raw(unsafe { bindings::task_euid(self.0.get()) })
+    }
+
     /// Determines whether the given task has pending signals.
     pub fn signal_pending(&self) -> bool {
         // SAFETY: By the type invariant, we know that `self.0` is valid.
         unsafe { bindings::signal_pending(self.0.get()) != 0 }
     }
 
+    /// Returns the given task's pid in the current pid namespace.
+    pub fn pid_in_current_ns(&self) -> Pid {
+        // SAFETY: We know that `self.0.get()` is valid by the type invariant, and passing a null
+        // pointer as the namespace is correct for using the current namespace.
+        unsafe { bindings::task_tgid_nr_ns(self.0.get(), ptr::null_mut()) }
+    }
+
     /// Wakes up the task.
     pub fn wake_up(&self) {
         // SAFETY: By the type invariant, we know that `self.0.get()` is non-null and valid.
@@ -175,3 +210,43 @@ unsafe impl crate::types::AlwaysRefCounted for Task {
         unsafe { bindings::put_task_struct(obj.cast().as_ptr()) }
     }
 }
+
+impl Kuid {
+    /// Get the current euid.
+    #[inline]
+    pub fn current_euid() -> Kuid {
+        // SAFETY: Just an FFI call.
+        Self::from_raw(unsafe { bindings::current_euid() })
+    }
+
+    /// Create a `Kuid` given the raw C type.
+    #[inline]
+    pub fn from_raw(kuid: bindings::kuid_t) -> Self {
+        Self { kuid }
+    }
+
+    /// Turn this kuid into the raw C type.
+    #[inline]
+    pub fn into_raw(self) -> bindings::kuid_t {
+        self.kuid
+    }
+
+    /// Converts this kernel UID into a userspace UID.
+    ///
+    /// Uses the namespace of the current task.
+    #[inline]
+    pub fn into_uid_in_current_ns(self) -> bindings::uid_t {
+        // SAFETY: Just an FFI call.
+        unsafe { bindings::from_kuid(bindings::current_user_ns(), self.kuid) }
+    }
+}
+
+impl PartialEq for Kuid {
+    #[inline]
+    fn eq(&self, other: &Kuid) -> bool {
+        // SAFETY: Just an FFI call.
+        unsafe { bindings::uid_eq(self.kuid, other.kuid) }
+    }
+}
+
+impl Eq for Kuid {}