1 // SPDX-License-Identifier: GPL-2.0
35 macro_rules! current {  macro
39         // leave current task context:
41         // * To return to userspace, the caller must leave the current scope.
47         unsafe { &*$crate::task::Task::current() }
62 /// The following is an example of getting the PID of the current thread with zero additional cost
66 /// let pid = current!().pid();
69 /// Getting the PID of the current process, also zero additional cost:
72 /// let pid = current!().group_leader().pid();
75 /// Getting the current task and storing it in some struct. The reference count is automatically
87 ///     fn new() -> Self {
89 ///             creator: ARef::from(&**current!()),
98 // SAFETY: By design, the only way to access a `Task` is via the `current` function or via an
109 /// Represents the [`Task`] in the `current` global.
111 /// This type exists to provide more efficient operations that are only valid on the current task.
112 /// For example, to retrieve the pid-namespace of a task, you must use rcu protection unless it is
113 /// the current task.
126 /// Other operations temporarily create a new sub-context:
142     fn deref(&self) -> &Task {  in deref()
157     /// Returns a raw pointer to the current task.
161     pub fn current_raw() -> *mut bindings::task_struct {  in current_raw()
162         // SAFETY: Getting the current pointer is always safe.  in current_raw()
168     /// The recommended way to get the current task/thread is to use the
169     /// [`current`] macro because it is safe.
177     pub unsafe fn current() -> impl Deref<Target = CurrentTask> {  in current()  method
185             fn deref(&self) -> &Self::Target {  in current()
187                 // the `TaskRef`, which the caller of `Task::current()` has promised will not  in current()
188                 // outlive the task/thread for which `self.task` is the `current` pointer. Thus, it  in current()
202     pub fn as_ptr(&self) -> *mut bindings::task_struct {  in as_ptr()
207     pub fn pid(&self) -> Pid {  in pid()
215     pub fn uid(&self) -> Kuid {  in uid()
222     pub fn euid(&self) -> Kuid {  in euid()
229     pub fn signal_pending(&self) -> bool {  in signal_pending()
236     pub fn get_pid_ns(&self) -> Option<ARef<PidNamespace>> {  in get_pid_ns()
252     pub fn tgid_nr_ns(&self, pidns: Option<&PidNamespace>) -> Pid {  in tgid_nr_ns()
274     /// Access the address space of the current task.
278     pub fn mm(&self) -> Option<&MmWithUser> {  in mm()
279         // SAFETY: The `mm` field of `current` is not modified from other threads, so reading it is  in mm()
287         // SAFETY: If `current->mm` is non-null, then it references a valid mm with a non-zero  in mm()
289         // `CurrentTask`, so it cannot escape the scope in which the current pointer was obtained.  in mm()
299         // In either case, it's not possible to read `current->mm` and keep using it after the  in mm()
304     /// Access the pid namespace of the current task.
311     pub fn active_pid_ns(&self) -> Option<&PidNamespace> {  in active_pid_ns()
313         // on the current task.  in active_pid_ns()
324         // From system call context retrieving the `PidNamespace` for the current task is always  in active_pid_ns()
326         // `PidNamespace` after `release_task()` for current will return `NULL` but no codepath  in active_pid_ns()
329         // SAFETY: If `current`'s pid ns is non-null, then it references a valid pid ns.  in active_pid_ns()
331         // escape the scope in which the current pointer was obtained, e.g. it cannot live past a  in active_pid_ns()
336     /// Returns the group leader of the current task.
337     pub fn group_leader(&self) -> &Task {  in group_leader()
339         // is the current task, which is guaranteed running.  in group_leader()
342         // SAFETY: `current->group_leader` stays valid for at least the duration in which `current`  in group_leader()
344         // only be used while `current` is still valid, thus still running.  in group_leader()
366     fn eq(&self, other: &Self) -> bool {  in eq()
374     /// Get the current euid.
376     pub fn current_euid() -> Kuid {  in current_euid()
383     pub fn from_raw(kuid: bindings::kuid_t) -> Self {  in from_raw()
389     pub fn into_raw(self) -> bindings::kuid_t {  in into_raw()
395     /// Uses the namespace of the current task.
397     pub fn into_uid_in_current_ns(self) -> bindings::uid_t {  in into_uid_in_current_ns()
405     fn eq(&self, other: &Kuid) -> bool {  in eq()
420 /// [`might_sleep()`]: https://docs.kernel.org/driver-api/basics.html#c.might_sleep
429         // SAFETY: `file.as_ptr()` is valid for reading and guaranteed to be nul-terminated.  in might_sleep()