libbinder: update getCallingPid docs
Bug: 297833427
Test: N/A
Change-Id: I406d2dbe68e79fa642df86f979a3f2332a4014bb
diff --git a/libs/binder/include/binder/IPCThreadState.h b/libs/binder/include/binder/IPCThreadState.h
index 9347ce4..dc5b1a1 100644
--- a/libs/binder/include/binder/IPCThreadState.h
+++ b/libs/binder/include/binder/IPCThreadState.h
@@ -62,8 +62,13 @@
/**
* Returns the PID of the process which has made the current binder
- * call. If not in a binder call, this will return getpid. If the
- * call is oneway, this will return 0.
+ * call. If not in a binder call, this will return getpid.
+ *
+ * Warning: oneway transactions do not receive PID. Even if you expect
+ * a transaction to be synchronous, a misbehaving client could send it
+ * as an asynchronous call and result in a 0 PID here. Additionally, if
+ * there is a race and the calling process dies, the PID may still be
+ * 0 for a synchronous call.
*/
[[nodiscard]] pid_t getCallingPid() const;
diff --git a/libs/binder/ndk/include_ndk/android/binder_ibinder.h b/libs/binder/ndk/include_ndk/android/binder_ibinder.h
index db2d2c1..b1ab7b0 100644
--- a/libs/binder/ndk/include_ndk/android/binder_ibinder.h
+++ b/libs/binder/ndk/include_ndk/android/binder_ibinder.h
@@ -390,6 +390,12 @@
* calling process dies and is replaced with another process with elevated permissions and the same
* PID.
*
+ * Warning: oneway transactions do not receive PID. Even if you expect
+ * a transaction to be synchronous, a misbehaving client could send it
+ * as a synchronous call and result in a 0 PID here. Additionally, if
+ * there is a race and the calling process dies, the PID may still be
+ * 0 for a synchronous call.
+ *
* Available since API level 29.
*
* \return calling pid or the current process's PID if this thread isn't processing a transaction.
diff --git a/libs/binder/rust/src/state.rs b/libs/binder/rust/src/state.rs
index a3a2562..8a06274 100644
--- a/libs/binder/rust/src/state.rs
+++ b/libs/binder/rust/src/state.rs
@@ -101,13 +101,16 @@
/// dies and is replaced with another process with elevated permissions and
/// the same PID.
///
+ /// Warning: oneway transactions do not receive PID. Even if you expect
+ /// a transaction to be synchronous, a misbehaving client could send it
+ /// as a synchronous call and result in a 0 PID here. Additionally, if
+ /// there is a race and the calling process dies, the PID may still be
+ /// 0 for a synchronous call.
+ ///
/// Available since API level 29.
///
/// \return calling pid or the current process's PID if this thread isn't
/// processing a transaction.
- ///
- /// If the transaction being processed is a oneway transaction, then this
- /// method will return 0.
pub fn get_calling_pid() -> pid_t {
// Safety: Safe FFI
unsafe { sys::AIBinder_getCallingPid() }