From 0e8efe94f7be45b19b5808cd4eeeb42a31d921a5 Mon Sep 17 00:00:00 2001
From: SteveLauC <stevelauc@outlook.com>
Date: Sun, 7 Jan 2024 10:12:06 +0800
Subject: [PATCH] feat: clock_nanosleep() (#2277)

---
 changelog/2277.added.md |  1 +
 src/time.rs             | 52 +++++++++++++++++++++++++++++++++++++++++
 test/test_time.rs       | 25 ++++++++++++++++++++
 3 files changed, 78 insertions(+)
 create mode 100644 changelog/2277.added.md

diff --git a/changelog/2277.added.md b/changelog/2277.added.md
new file mode 100644
index 0000000000..0b6e8611c4
--- /dev/null
+++ b/changelog/2277.added.md
@@ -0,0 +1 @@
+Add `clock_nanosleep()`
diff --git a/src/time.rs b/src/time.rs
index 96e84900dd..72915c25df 100644
--- a/src/time.rs
+++ b/src/time.rs
@@ -199,3 +199,55 @@ pub fn clock_getcpuclockid(pid: Pid) -> Result<ClockId> {
         Err(Errno::from_i32(ret))
     }
 }
+
+#[cfg(any(
+    linux_android,
+    solarish,
+    freebsdlike,
+    target_os = "netbsd",
+    target_os = "hurd",
+    target_os = "aix"
+))]
+libc_bitflags! {
+    /// Flags that are used for arming the timer.
+    pub struct ClockNanosleepFlags: libc::c_int {
+        TIMER_ABSTIME;
+    }
+}
+
+/// Suspend execution of this thread for the amount of time specified by `request`
+/// and measured against the clock speficied by `clock_id`. If `flags` is
+/// `TIMER_ABSTIME`, this function will suspend execution until the time value of
+/// clock_id reaches the absolute time specified by `request`. If a signal is caught
+/// by a signal-catching function, or a signal causes the process to terminate,
+/// this sleep is interrrupted.
+///
+/// see also [man 3 clock_nanosleep](https://pubs.opengroup.org/onlinepubs/009695399/functions/clock_nanosleep.html)
+#[cfg(any(
+    linux_android,
+    solarish,
+    freebsdlike,
+    target_os = "netbsd",
+    target_os = "hurd",
+    target_os = "aix"
+))]
+pub fn clock_nanosleep(
+    clock_id: ClockId,
+    flags: ClockNanosleepFlags,
+    request: &TimeSpec,
+) -> Result<TimeSpec> {
+    let mut remain = TimeSpec::new(0, 0);
+    let ret = unsafe {
+        libc::clock_nanosleep(
+            clock_id.as_raw(),
+            flags.bits(),
+            request.as_ref() as *const _,
+            remain.as_mut() as *mut _,
+        )
+    };
+    if ret == 0 {
+        Ok(remain)
+    } else {
+        Err(Errno::from_i32(ret))
+    }
+}
diff --git a/test/test_time.rs b/test/test_time.rs
index 6d7dfbedc0..64c8161dbf 100644
--- a/test/test_time.rs
+++ b/test/test_time.rs
@@ -39,3 +39,28 @@ pub fn test_clock_id_pid_cpu_clock_id() {
         .unwrap()
         .unwrap();
 }
+
+#[cfg(any(
+    linux_android,
+    solarish,
+    freebsdlike,
+    target_os = "netbsd",
+    target_os = "hurd",
+    target_os = "aix"
+))]
+#[test]
+pub fn test_clock_nanosleep() {
+    use nix::{
+        sys::time::{TimeSpec, TimeValLike},
+        time::{clock_nanosleep, ClockNanosleepFlags},
+    };
+
+    let sleep_time = TimeSpec::microseconds(1);
+    let res = clock_nanosleep(
+        ClockId::CLOCK_MONOTONIC,
+        ClockNanosleepFlags::empty(),
+        &sleep_time,
+    );
+    let expected = TimeSpec::microseconds(0);
+    assert_eq!(res, Ok(expected));
+}