Add VxWorks support in unix module

Author: biabbas

src/unix.rs

@@ -12,6 +12,8 @@ use libc::SCHED_NORMAL as SCHED_OTHER;
 use libc::SCHED_OTHER;
 #[cfg(any(target_os = "linux", target_os = "android"))]
 use libc::{SCHED_BATCH, SCHED_IDLE};
+#[cfg(target_os = "vxworks")]
+use libc::SCHED_SPORADIC;
 use libc::{SCHED_FIFO, SCHED_RR};
 
 use crate::{Error, ThreadPriority, ThreadPriorityValue};
@@ -51,6 +53,8 @@ fn errno() -> libc::c_int {
                 *libc::__errno_location()
             } else if #[cfg(any(target_os = "macos", target_os = "ios", target_os = "freebsd"))] {
                 *libc::__error()
+            }  else if #[cfg(target_os = "vxworks")] {
+                libc::errnoGet()
             } else {
                 compile_error!("Your OS is probably not supported.")
             }
@@ -67,6 +71,8 @@ fn set_errno(number: libc::c_int) {
                 *libc::__errno_location() = number;
             } else if #[cfg(any(target_os = "macos", target_os = "ios", target_os = "freebsd"))] {
                 *libc::__error() = number;
+            } else if #[cfg(target_os = "vxworks")] {
+                let _ = libc::errnoSet(number);
             } else {
                 compile_error!("Your OS is probably not supported.")
             }
@@ -171,6 +177,9 @@ pub enum RealtimeThreadSchedulePolicy {
     Fifo,
     /// A round-robin policy
     RoundRobin,
+    // Policy similar to Fifo
+    #[cfg(target_os = "vxworks")]
+    Sporadic,
     /// A deadline policy. Note, due to Linux expecting a pid_t and not a pthread_t, the given
     /// [ThreadId](struct.ThreadId) will be interpreted as a pid_t. This policy is NOT
     /// POSIX-compatible, so we only include it for linux targets.
@@ -186,6 +195,8 @@ impl RealtimeThreadSchedulePolicy {
         match self {
             RealtimeThreadSchedulePolicy::Fifo => SCHED_FIFO,
             RealtimeThreadSchedulePolicy::RoundRobin => SCHED_RR,
+            #[cfg(target_os = "vxworks")]
+            RealtimeThreadSchedulePolicy::Sporadic => SCHED_SPORADIC,
             #[cfg(all(
                 any(target_os = "linux", target_os = "android"),
                 not(target_arch = "wasm32")
@@ -284,6 +295,10 @@ impl ThreadSchedulePolicy {
             SCHED_RR => Ok(ThreadSchedulePolicy::Realtime(
                 RealtimeThreadSchedulePolicy::RoundRobin,
             )),
+            #[cfg(target_os = "vxworks")]
+            SCHED_SPORADIC => Ok(ThreadSchedulePolicy::Realtime(
+                RealtimeThreadSchedulePolicy::Sporadic,
+            )),
             #[cfg(all(
                 any(target_os = "linux", target_os = "android"),
                 not(target_arch = "wasm32")
@@ -346,8 +361,8 @@ impl ThreadPriority {
                                 PriorityPolicyEdgeValueType::Maximum => NICENESS_MAX as libc::c_int,
                             })
                         }
-                    } else if #[cfg(any(target_os = "macos", target_os = "ios"))] {
-                        // macOS/iOS allows specifying the priority using sched params.
+                    } else if #[cfg(any(target_os = "macos", target_os = "ios", target_os = "vxworks"))] {
+                        // macOS/iOS and VxWorks allow specifying the priority using sched params.
                         get_edge_priority(policy)
                     } else {
                         Err(Error::Priority(
@@ -426,7 +441,7 @@ impl ThreadPriority {
                 // for the SCHED_OTHER policy.
                 // <https://www.usenix.org/legacy/publications/library/proceedings/bsdcon02/full_papers/gerbarg/gerbarg_html/index.html>
                 #[cfg(all(
-                    any(target_os = "macos", target_os = "ios"),
+                    any(target_os = "macos", target_os = "ios", target_os = "vxworks"),
                     not(target_arch = "wasm32")
                 ))]
                 ThreadSchedulePolicy::Normal(_) => {
@@ -571,10 +586,10 @@ pub fn set_thread_priority_and_policy(
         }
         _ => {
             let fixed_priority = priority.to_posix(policy)?;
-            // On macOS and iOS it is possible to set the priority
+            // On VxWorks, macOS and iOS it is possible to set the priority
             // this way.
             if matches!(policy, ThreadSchedulePolicy::Realtime(_))
-                || cfg!(any(target_os = "macos", target_os = "ios"))
+                || cfg!(any(target_os = "macos", target_os = "ios", target_os = "vxworks"))
             {
                 // If the policy is a realtime one, the priority is set via
                 // pthread_setschedparam.
@@ -613,6 +628,9 @@ pub fn set_thread_priority_and_policy(
 
                 // Normal priority threads adjust relative priority through niceness.
                 set_errno(0);
+                // VxWorks does not have setpriority function call. Control never
+                // reaches this statement because of the cfg condition in if
+                #[cfg(not(target_os = "vxworks"))]
                 let ret = unsafe { libc::setpriority(libc::PRIO_PROCESS, 0, fixed_priority) };
                 if ret != 0 {
                     return Err(Error::OS(errno()));