implement wasi::poll_oneoff for write on Unix-like platforms

wasmerio · Aug 15, 2019 · 0c45707 · 0c45707
1 parent d733989
commit 0c45707
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Showing 7 changed files with 118 additions and 68 deletions.
diff --git a/lib/wasi-tests/tests/wasitests/poll_oneoff.rs b/lib/wasi-tests/tests/wasitests/poll_oneoff.rs
@@ -4,10 +4,16 @@ fn test_poll_oneoff() {
         "../../wasitests/poll_oneoff.wasm",
         "poll_oneoff",
         vec![],
-        vec![(
-            "hamlet".to_string(),
-            ::std::path::PathBuf::from("wasitests/test_fs/hamlet")
-        ),],
+        vec![
+            (
+                "hamlet".to_string(),
+                ::std::path::PathBuf::from("wasitests/test_fs/hamlet")
+            ),
+            (
+                "temp".to_string(),
+                ::std::path::PathBuf::from("wasitests/test_fs/temp")
+            ),
+        ],
         vec![],
         "../../wasitests/poll_oneoff.out"
     );

diff --git a/lib/wasi-tests/wasitests/poll_oneoff.out b/lib/wasi-tests/wasitests/poll_oneoff.out
@@ -1 +1,2 @@
 __wasi_event_t { userdata: 1193046, error: 0, type_: 1, u: __wasi_event_u { __wasi_event_fd_readwrite_t { nbytes: 2259, flags: 0 } } }
+[__wasi_event_t { userdata: 1193046, error: 0, type_: 1, u: __wasi_event_u { __wasi_event_fd_readwrite_t { nbytes: 2259, flags: 0 } } }, __wasi_event_t { userdata: 1193046, error: 0, type_: 2, u: __wasi_event_u { __wasi_event_fd_readwrite_t { nbytes: 1234, flags: 0 } } }]
diff --git a/lib/wasi-tests/wasitests/poll_oneoff.rs b/lib/wasi-tests/wasitests/poll_oneoff.rs
@@ -1,5 +1,6 @@
 // Args:
 // mapdir: hamlet:wasitests/test_fs/hamlet
+// mapdir: temp:wasitests/test_fs/temp
 
 use std::fs;
 use std::io::{Read, Seek, SeekFrom};
@@ -95,15 +96,27 @@ pub struct __wasi_subscription_t {
 }
 
 #[cfg(target_os = "wasi")]
-fn poll_read(fds: &[u32]) -> Result<Vec<__wasi_event_t>, u16> {
+fn poll(fds: &[u32], read: &[bool], write: &[bool]) -> Result<Vec<__wasi_event_t>, u16> {
+    assert!(fds.len() == read.len() && read.len() == write.len());
+
     let mut in_ = fds
         .iter()
-        .map(|n| __wasi_subscription_t {
-            userdata: 0x123456,
-            type_: __WASI_EVENTTYPE_FD_READ,
-            u: __wasi_subscription_u {
-                fd_readwrite: __wasi_subscription_fs_readwrite_t { fd: *n as u32 },
-            },
+        .enumerate()
+        .map(|(i, n)| {
+            let mut type_ = 0;
+            if read[i] {
+                type_ |= __WASI_EVENTTYPE_FD_READ;
+            }
+            if write[i] {
+                type_ |= __WASI_EVENTTYPE_FD_WRITE;
+            }
+            __wasi_subscription_t {
+                userdata: 0x123456,
+                type_,
+                u: __wasi_subscription_u {
+                    fd_readwrite: __wasi_subscription_fs_readwrite_t { fd: *n as u32 },
+                },
+            }
         })
         .collect::<Vec<_>>();
     let mut out_ = vec![Default::default(); in_.len()];
@@ -131,20 +144,40 @@ fn main() {
     let mut base = PathBuf::from("/");
 
     let path = base.join("hamlet/act4/scene1.txt");
-    let mut file = fs::File::open(&path).expect("Could not open file");
-    let mut buffer = [0u8; 64];
-
-    #[cfg(target_os = "wasi")]
+    let path2 = base.join("temp/poll_oneoff_write.txt");
     {
-        let fds = vec![file.as_raw_fd()];
-        let mut result = poll_read(fds.as_slice()).expect("First poll");
-        while result[0].error != 0 {
-            result = poll_read(fds.as_slice()).expect("subsequent polls");
+        let mut file = fs::File::open(&path).expect("Could not open file");
+        let mut file2 = fs::OpenOptions::new()
+            .create(true)
+            .write(true)
+            .truncate(true)
+            .open(&path2)
+            .expect("Could not open file");
+        file2.set_len(1234).unwrap();
+
+        #[cfg(target_os = "wasi")]
+        {
+            let fds = vec![file.as_raw_fd()];
+            let mut result = poll(fds.as_slice(), &[true], &[false]).expect("First poll");
+            while result[0].error != 0 {
+                result = poll(fds.as_slice(), &[true], &[false]).expect("subsequent polls");
+            }
+            println!("{:?}", result[0]);
+
+            let fds = vec![file.as_raw_fd(), file2.as_raw_fd()];
+            result = poll(fds.as_slice(), &[true, false], &[false, true]).expect("First poll");
+            while result[0].error != 0 {
+                result =
+                    poll(fds.as_slice(), &[true, false], &[false, true]).expect("subsequent polls");
+            }
+            println!("{:?}", result);
+        }
+        #[cfg(not(target_os = "wasi"))]
+        {
+            println!("{}", "__wasi_event_t { userdata: 1193046, error: 0, type_: 1, u: __wasi_event_u { __wasi_event_fd_readwrite_t { nbytes: 2259, flags: 0 } } }");
+            println!("{}", "[__wasi_event_t { userdata: 1193046, error: 0, type_: 1, u: __wasi_event_u { __wasi_event_fd_readwrite_t { nbytes: 2259, flags: 0 } } }, __wasi_event_t { userdata: 1193046, error: 0, type_: 2, u: __wasi_event_u { __wasi_event_fd_readwrite_t { nbytes: 1234, flags: 0 } } }]");
         }
-        println!("{:?}", result[0]);
-    }
-    #[cfg(not(target_os = "wasi"))]
-    {
-        println!("{}", "__wasi_event_t { userdata: 1193046, error: 0, type_: 1, u: __wasi_event_u { __wasi_event_fd_readwrite_t { nbytes: 2259, flags: 0 } } }");
     }
+
+    std::fs::remove_file(path2).unwrap();
 }
diff --git a/lib/wasi-tests/wasitests/poll_oneoff.wasm b/lib/wasi-tests/wasitests/poll_oneoff.wasm
diff --git a/lib/wasi/src/state/types.rs b/lib/wasi/src/state/types.rs
@@ -323,7 +323,7 @@ pub(crate) fn poll(
     for (i, fd) in fds.into_iter().enumerate() {
         seen_events[i] = platform_poll_events_to_pollevent_set(fd.revents);
     }
-    // unwrap is safe because we check the error above
+    // unwrap is safe because we check for negative values above
     Ok(result.try_into().unwrap())
 }
 

diff --git a/lib/wasi/src/syscalls/mod.rs b/lib/wasi/src/syscalls/mod.rs
@@ -2312,51 +2312,52 @@ pub fn poll_oneoff(
         } else {
             unimplemented!("Clock events are not yet implemented!");
         }
-        let mut seen_events = vec![Default::default(); in_events.len()];
-        wasi_try!(poll(
-            fds.as_slice(),
-            in_events.as_slice(),
-            seen_events.as_mut_slice()
-        )
-        .map_err(|e| e.into_wasi_err()));
-
-        for (i, seen_event) in seen_events.into_iter().enumerate() {
-            let mut flags = 0;
-            let mut error = __WASI_EAGAIN;
-            let mut bytes_available = 0;
-            let event_iter = iterate_poll_events(seen_event);
-            for event in event_iter {
-                match event {
-                    PollEvent::PollError => error = __WASI_EIO,
-                    PollEvent::PollHangUp => flags = __WASI_EVENT_FD_READWRITE_HANGUP,
-                    PollEvent::PollInvalid => error = __WASI_EINVAL,
-                    PollEvent::PollIn => {
-                        bytes_available =
-                            wasi_try!(fds[i].bytes_available().map_err(|e| e.into_wasi_err()));
-                        error = __WASI_ESUCCESS;
-                    }
-                    PollEvent::PollOut => {
-                        error = __WASI_ESUCCESS;
-                        unimplemented!("Write in wasi::poll_oneoff not yet supported!")
-                    }
+    }
+    let mut seen_events = vec![Default::default(); in_events.len()];
+    wasi_try!(poll(
+        fds.as_slice(),
+        in_events.as_slice(),
+        seen_events.as_mut_slice()
+    )
+    .map_err(|e| e.into_wasi_err()));
+
+    for (i, seen_event) in seen_events.into_iter().enumerate() {
+        let mut flags = 0;
+        let mut error = __WASI_EAGAIN;
+        let mut bytes_available = 0;
+        let event_iter = iterate_poll_events(seen_event);
+        for event in event_iter {
+            match event {
+                PollEvent::PollError => error = __WASI_EIO,
+                PollEvent::PollHangUp => flags = __WASI_EVENT_FD_READWRITE_HANGUP,
+                PollEvent::PollInvalid => error = __WASI_EINVAL,
+                PollEvent::PollIn => {
+                    bytes_available =
+                        wasi_try!(fds[i].bytes_available().map_err(|e| e.into_wasi_err()));
+                    error = __WASI_ESUCCESS;
+                }
+                PollEvent::PollOut => {
+                    bytes_available =
+                        wasi_try!(fds[i].bytes_available().map_err(|e| e.into_wasi_err()));
+                    error = __WASI_ESUCCESS;
                 }
             }
-            let event = __wasi_event_t {
-                userdata: subscription_array[i].get().userdata,
-                error,
-                type_: subscription_array[i].get().type_,
-                u: unsafe {
-                    __wasi_event_u {
-                        fd_readwrite: __wasi_event_fd_readwrite_t {
-                            nbytes: bytes_available as u64,
-                            flags,
-                        },
-                    }
-                },
-            };
-            event_array[events_seen].set(event);
-            events_seen += 1;
         }
+        let event = __wasi_event_t {
+            userdata: subscription_array[i].get().userdata,
+            error,
+            type_: subscription_array[i].get().type_,
+            u: unsafe {
+                __wasi_event_u {
+                    fd_readwrite: __wasi_event_fd_readwrite_t {
+                        nbytes: bytes_available as u64,
+                        flags,
+                    },
+                }
+            },
+        };
+        event_array[events_seen].set(event);
+        events_seen += 1;
     }
     out_ptr.set(events_seen as u32);
     __WASI_ESUCCESS

diff --git a/lib/wasi/src/syscalls/types.rs b/lib/wasi/src/syscalls/types.rs
@@ -160,6 +160,15 @@ pub union __wasi_event_u {
     pub fd_readwrite: __wasi_event_fd_readwrite_t,
 }
 
+// TODO: remove this implementation of Debug when `__wasi_event_u` gets more than 1 variant
+impl std::fmt::Debug for __wasi_event_u {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("__wasi_event_u")
+            .field("fd_readwrite", unsafe { &self.fd_readwrite })
+            .finish()
+    }
+}
+
 #[derive(Debug, Copy, Clone)]
 pub enum EventEnum {
     FdReadWrite {
@@ -178,7 +187,7 @@ impl EventEnum {
     }
 }
 
-#[derive(Copy, Clone)]
+#[derive(Debug, Copy, Clone)]
 #[repr(C)]
 pub struct __wasi_event_t {
     pub userdata: __wasi_userdata_t,
Original file line number	Diff line number	Diff line change
		@@ -1 +1,2 @@
		__wasi_event_t { userdata: 1193046, error: 0, type_: 1, u: __wasi_event_u { __wasi_event_fd_readwrite_t { nbytes: 2259, flags: 0 } } }
		[__wasi_event_t { userdata: 1193046, error: 0, type_: 1, u: __wasi_event_u { __wasi_event_fd_readwrite_t { nbytes: 2259, flags: 0 } } }, __wasi_event_t { userdata: 1193046, error: 0, type_: 2, u: __wasi_event_u { __wasi_event_fd_readwrite_t { nbytes: 1234, flags: 0 } } }]