Merge patch series "File abstractions needed by Rust Binder"

Alice Ryhl <aliceryhl@google.com> says:

This patchset contains the file abstractions needed by the Rust
implementation of the Binder driver.

Please see the Rust Binder RFC for usage examples:
https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-0-08ba9197f637@google.com

Users of "rust: types: add `NotThreadSafe`":
	[PATCH 5/9] rust: file: add `FileDescriptorReservation`

Users of "rust: task: add `Task::current_raw`":
	[PATCH 7/9] rust: file: add `Kuid` wrapper
	[PATCH 8/9] rust: file: add `DeferredFdCloser`

Users of "rust: file: add Rust abstraction for `struct file`":
	[PATCH RFC 02/20] rust_binder: add binderfs support to Rust binder
	[PATCH RFC 03/20] rust_binder: add threading support

Users of "rust: cred: add Rust abstraction for `struct cred`":
	[PATCH RFC 05/20] rust_binder: add nodes and context managers
	[PATCH RFC 06/20] rust_binder: add oneway transactions
	[PATCH RFC 11/20] rust_binder: send nodes in transaction
	[PATCH RFC 13/20] rust_binder: add BINDER_TYPE_FD support

Users of "rust: security: add abstraction for secctx":
	[PATCH RFC 06/20] rust_binder: add oneway transactions

Users of "rust: file: add `FileDescriptorReservation`":
	[PATCH RFC 13/20] rust_binder: add BINDER_TYPE_FD support
	[PATCH RFC 14/20] rust_binder: add BINDER_TYPE_FDA support

Users of "rust: file: add `Kuid` wrapper":
	[PATCH RFC 05/20] rust_binder: add nodes and context managers
	[PATCH RFC 06/20] rust_binder: add oneway transactions

Users of "rust: file: add abstraction for `poll_table`":
	[PATCH RFC 07/20] rust_binder: add epoll support

This patchset has some uses of read_volatile in place of READ_ONCE.
Please see the following rfc for context on this:
https://lore.kernel.org/all/20231025195339.1431894-1-boqun.feng@gmail.com/

* patches from https://lore.kernel.org/r/20240915-alice-file-v10-0-88484f7a3dcf@google.com:
  rust: file: add abstraction for `poll_table`
  rust: file: add `Kuid` wrapper
  rust: file: add `FileDescriptorReservation`
  rust: security: add abstraction for secctx
  rust: cred: add Rust abstraction for `struct cred`
  rust: file: add Rust abstraction for `struct file`
  rust: task: add `Task::current_raw`
  rust: types: add `NotThreadSafe`

Link: https://lore.kernel.org/r/20240915-alice-file-v10-0-88484f7a3dcf@google.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

5 files changed, 86 insertions, 0 deletions

diff --git a/rust/helpers/cred.c b/rust/helpers/cred.c
new file mode 100644
index 000000000000..fde7ae20cdd1
--- /dev/null
+++ b/rust/helpers/cred.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/cred.h>
+
+const struct cred *rust_helper_get_cred(const struct cred *cred)
+{
+	return get_cred(cred);
+}
+
+void rust_helper_put_cred(const struct cred *cred)
+{
+	put_cred(cred);
+}
diff --git a/rust/helpers/fs.c b/rust/helpers/fs.c
new file mode 100644
index 000000000000..a75c96763372
--- /dev/null
+++ b/rust/helpers/fs.c
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2024 Google LLC.
+ */
+
+#include <linux/fs.h>
+
+struct file *rust_helper_get_file(struct file *f)
+{
+	return get_file(f);
+}
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index 30f40149f3a9..62022b18caf5 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -11,12 +11,15 @@
 #include "bug.c"
 #include "build_assert.c"
 #include "build_bug.c"
+#include "cred.c"
 #include "err.c"
+#include "fs.c"
 #include "kunit.c"
 #include "mutex.c"
 #include "page.c"
 #include "rbtree.c"
 #include "refcount.c"
+#include "security.c"
 #include "signal.c"
 #include "slab.c"
 #include "spinlock.c"
diff --git a/rust/helpers/security.c b/rust/helpers/security.c
new file mode 100644
index 000000000000..239e5b4745fe
--- /dev/null
+++ b/rust/helpers/security.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/security.h>
+
+#ifndef CONFIG_SECURITY
+void rust_helper_security_cred_getsecid(const struct cred *c, u32 *secid)
+{
+	security_cred_getsecid(c, secid);
+}
+
+int rust_helper_security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+{
+	return security_secid_to_secctx(secid, secdata, seclen);
+}
+
+void rust_helper_security_release_secctx(char *secdata, u32 seclen)
+{
+	security_release_secctx(secdata, seclen);
+}
+#endif
diff --git a/rust/helpers/task.c b/rust/helpers/task.c
index 7ac789232d11..7d66487db831 100644
--- a/rust/helpers/task.c
+++ b/rust/helpers/task.c
@@ -17,3 +17,41 @@ void rust_helper_put_task_struct(struct task_struct *t)
 {
 	put_task_struct(t);
 }
+
+kuid_t rust_helper_task_uid(struct task_struct *task)
+{
+	return task_uid(task);
+}
+
+kuid_t rust_helper_task_euid(struct task_struct *task)
+{
+	return task_euid(task);
+}
+
+#ifndef CONFIG_USER_NS
+uid_t rust_helper_from_kuid(struct user_namespace *to, kuid_t uid)
+{
+	return from_kuid(to, uid);
+}
+#endif /* CONFIG_USER_NS */
+
+bool rust_helper_uid_eq(kuid_t left, kuid_t right)
+{
+	return uid_eq(left, right);
+}
+
+kuid_t rust_helper_current_euid(void)
+{
+	return current_euid();
+}
+
+struct user_namespace *rust_helper_current_user_ns(void)
+{
+	return current_user_ns();
+}
+
+pid_t rust_helper_task_tgid_nr_ns(struct task_struct *tsk,
+				  struct pid_namespace *ns)
+{
+	return task_tgid_nr_ns(tsk, ns);
+}