Merge branch 'fix-ppoll' into 'master'

Handle signal mask in epoll_pwait

See merge request redox-os/relibc!879

redox-rt/src/signal.rs

@@ -783,6 +783,34 @@ pub fn await_signal_async(inner_allowset: u64) -> Result<Unreachable> {
     res?;
     unreachable!()
 }
+
+/// Run a callback with the specified signal mask, atomically
+pub fn callback_or_signal_async<T, F: FnOnce() -> Result<T>>(
+    inner_allowset: u64,
+    callback: F,
+) -> Result<T> {
+    let _guard = tmp_disable_signals();
+    let control = &unsafe { Tcb::current().unwrap() }.os_specific.control;
+
+    let old_allowset = get_allowset_raw(&control.word);
+    set_allowset_raw(&control.word, old_allowset, inner_allowset);
+    let res = callback();
+    if let Err(err) = &res {
+        if err.errno == EINTR {
+            // Run trampoline if EINTR returned
+            unsafe {
+                manually_enter_trampoline();
+            }
+        }
+    }
+
+    // POSIX says it shall restore the mask to what it was prior to the call, which is interpreted
+    // as allowing any changes to sigprocmask inside the signal handler, to be discarded.
+    set_allowset_raw(&control.word, inner_allowset, old_allowset);
+
+    res
+}
+
 /*#[unsafe(no_mangle)]
 pub extern "C" fn __redox_rt_debug_sigctl() {
     let tcb = &RtTcb::current().control;
@@ -830,6 +858,7 @@ pub fn await_signal_sync(inner_allowset: u64, timeout: Option<&TimeSpec>) -> Res
         // Normally ETIMEDOUT but not for sigtimedwait.
         .ok_or(Error::new(EAGAIN))
 }
+
 fn try_claim_multiple(
     mut proc_pending: u64,
     mut thread_pending: u64,

src/header/poll/mod.rs

@@ -11,6 +11,7 @@ use crate::{
     error::ResultExt,
     fs::File,
     header::{
+        errno::EBADF,
         signal::sigset_t,
         sys_epoll::{
             EPOLL_CLOEXEC, EPOLL_CTL_ADD, EPOLLERR, EPOLLHUP, EPOLLIN, EPOLLNVAL, EPOLLOUT,
@@ -19,7 +20,10 @@ use crate::{
         },
         time::timespec,
     },
-    platform::types::{c_int, c_short, c_ulong},
+    platform::{
+        self,
+        types::{c_int, c_short, c_ulong},
+    },
 };
 
 pub const POLLIN: c_short = 0x001;
@@ -65,12 +69,14 @@ pub fn poll_epoll(fds: &mut [pollfd], timeout: c_int, sigmask: *const sigset_t)
         File::new(epfd)
     };
 
+    let mut closed = 0;
     for i in 0..fds.len() {
         let mut pfd = &mut fds[i];
 
-        // Ignore the entry with negative fd, set the revents to 0
+        pfd.revents = 0;
+
+        // Ignore the entry with negative fd
         if pfd.fd < 0 {
-            pfd.revents = 0;
             continue;
         }
 
@@ -86,13 +92,21 @@ pub fn poll_epoll(fds: &mut [pollfd], timeout: c_int, sigmask: *const sigset_t)
             }
         }
 
-        pfd.revents = 0;
-
         if unsafe { epoll_ctl(*ep, EPOLL_CTL_ADD, pfd.fd, &mut event) } < 0 {
-            return -1;
+            if platform::ERRNO.get() == EBADF {
+                pfd.revents |= POLLNVAL;
+                closed += 1;
+            } else {
+                return -1;
+            }
         }
     }
 
+    // Early exit if there are fds, and all are closed (revents = POLLNVAL)
+    if closed > 0 && closed == fds.len() {
+        return closed as i32;
+    }
+
     let mut events: [epoll_event; 32] = unsafe { mem::zeroed() };
     let res = unsafe {
         epoll_pwait(

src/platform/redox/epoll.rs

@@ -96,9 +96,8 @@ impl PalEpoll for Sys {
         events: *mut epoll_event,
         maxevents: c_int,
         timeout: c_int,
-        _sigset: *const sigset_t,
+        sigset: *const sigset_t,
     ) -> Result<usize, Errno> {
-        // TODO: sigset
         assert_eq!(mem::size_of::<epoll_event>(), mem::size_of::<Event>());
 
         if maxevents <= 0 {
@@ -131,12 +130,24 @@ impl PalEpoll for Sys {
             None
         };
 
-        let bytes_read = Sys::read(epfd, unsafe {
-            slice::from_raw_parts_mut(
-                events as *mut u8,
-                maxevents as usize * mem::size_of::<syscall::Event>(),
-            )
-        })?;
+        let callback = || {
+            let res = syscall::read(epfd as usize, unsafe {
+                slice::from_raw_parts_mut(
+                    events as *mut u8,
+                    maxevents as usize * mem::size_of::<syscall::Event>(),
+                )
+            });
+            res
+        };
+
+        let bytes_read = if sigset.is_null() {
+            callback()
+        } else {
+            // Allowset is inverse of sigset mask
+            let allowset = !*sigset;
+            redox_rt::signal::callback_or_signal_async(allowset, callback)
+        }?;
+
         let read = bytes_read as usize / mem::size_of::<syscall::Event>();
 
         let mut count = 0;