Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 91 insertions, 0 deletions

diff --git a/third_party/rust/dbus/examples/rtkit.rs b/third_party/rust/dbus/examples/rtkit.rs
new file mode 100644
index 0000000000..823c899bd0
--- /dev/null
+++ b/third_party/rust/dbus/examples/rtkit.rs
@@ -0,0 +1,91 @@
+/* This example asks the rtkit service to make our thread realtime priority.
+   Rtkit puts a few limitations on us to let us become realtime, such as setting
+   RLIMIT_RTTIME correctly, hence the syscalls. */
+
+extern crate dbus;
+extern crate libc;
+
+use std::cmp;
+use libc::c_int;
+
+use dbus::{Connection, BusType, Props, MessageItem, Message};
+
+/* External C stuff. Currently only working for x86_64 */
+
+#[allow(non_upper_case_globals)]
+#[cfg(target_arch = "x86_64")]
+static SYS_gettid: c_int = 186;
+
+static RLIMIT_RTTIME: c_int = 15;
+
+#[repr(C)]
+#[cfg(target_arch = "x86_64")]
+#[derive(Copy, Clone)]
+struct rlimit {
+    rlim_cur: u64,
+    rlim_max: u64,
+}
+
+extern "C" {
+    fn syscall(num: c_int, ...) -> c_int;
+
+    fn getrlimit(resource: c_int, rlim: *mut rlimit) -> c_int;
+    fn setrlimit(resource: c_int, rlim: *const rlimit) -> c_int;
+}
+
+fn item_as_i64(i: MessageItem) -> Result<i64, Box<std::error::Error>> {
+    match i {
+        MessageItem::Int32(i) => Ok(i as i64),
+        MessageItem::Int64(i) => Ok(i),
+        _ => Err(Box::from(&*format!("Property is not integer ({:?})", i)))
+    }
+}
+
+fn rtkit_set_realtime(c: &Connection, thread: u64, prio: u32) -> Result<(), ::dbus::Error> {
+    let mut m = Message::new_method_call("org.freedesktop.RealtimeKit1", "/org/freedesktop/RealtimeKit1",
+        "org.freedesktop.RealtimeKit1", "MakeThreadRealtime").unwrap();
+    m.append_items(&[thread.into(), prio.into()]);
+    let mut r = try!(c.send_with_reply_and_block(m, 10000));
+    r.as_result().map(|_| ())
+}
+
+fn make_realtime(prio: u32) -> Result<u32, Box<std::error::Error>> {
+    let c = try!(Connection::get_private(BusType::System));
+
+    let p = Props::new(&c, "org.freedesktop.RealtimeKit1", "/org/freedesktop/RealtimeKit1",
+        "org.freedesktop.RealtimeKit1", 10000);
+
+    // Make sure we don't fail by wanting too much
+    let max_prio = try!(item_as_i64(try!(p.get("MaxRealtimePriority")))) as u32;
+    let prio = cmp::min(prio, max_prio);
+
+    // Enforce RLIMIT_RTPRIO, also a must before asking rtkit for rtprio
+    let max_rttime = try!(item_as_i64(try!(p.get("RTTimeNSecMax")))) as u64;
+    let new_limit = rlimit { rlim_cur: max_rttime, rlim_max: max_rttime };
+    let mut old_limit = new_limit;
+    if unsafe { getrlimit(RLIMIT_RTTIME, &mut old_limit) } < 0 {
+        return Err(Box::from("getrlimit failed"));
+    }
+    if unsafe { setrlimit(RLIMIT_RTTIME, &new_limit) } < 0 {
+        return Err(Box::from("setrlimit failed"));
+    }
+
+    // Finally, let's ask rtkit to make us realtime
+    let thread_id = unsafe { syscall(SYS_gettid) };
+    let r = rtkit_set_realtime(&c, thread_id as u64, prio);
+
+    if r.is_err() {
+        unsafe { setrlimit(RLIMIT_RTTIME, &old_limit) };
+    }
+
+    try!(r);
+    Ok(prio)
+}
+
+
+fn main() {
+    match make_realtime(5) {
+        Ok(n) => println!("Got rtprio, level {}", n),
+        Err(e) => println!("No rtprio: {}", e),
+    }
+}