Add wasm32-unknown-emscripten target support

.github/workflows/ci.yml

@@ -634,3 +634,55 @@ jobs:
       - name: before_cache_script
         run: rm -rf $CARGO_HOME/registry/index
 
+  # Runs the test suite against wasm32-unknown-emscripten under Node.
+  emscripten:
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    # TEMPORARY: builds against the guybedford/emscripten `cf` fork, which
+    # carries the NODEFS/socket/blocking patches this target depends on. Once
+    # those land upstream the fork checkout can be dropped for a released emsdk.
+    steps:
+      - name: checkout
+        uses: actions/checkout@v4
+
+      - name: setup Rust
+        uses: dtolnay/rust-toolchain@nightly
+        with:
+          components: rust-src
+
+      # JSPI is the return-to-host bridge for blocking reads/writes; it needs a
+      # Node with JSPI on by default (V8 13.x+), not the one bundled with emsdk.
+      - name: setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 26
+
+      - name: record JSPI-capable node
+        run: echo "JSPI_NODE=$(which node)" >> "$GITHUB_ENV"
+
+      - name: install emsdk
+        run: |
+          git clone --depth 1 https://github.com/emscripten-core/emsdk.git
+          ./emsdk/emsdk install latest
+          ./emsdk/emsdk activate latest
+
+      - name: overlay guybedford/emscripten (cf) fork
+        run: |
+          git clone --branch cf https://github.com/guybedford/emscripten.git em-fork
+          python3 em-fork/bootstrap.py
+          rm -rf ./emsdk/upstream/emscripten
+          ln -s "$(pwd)/em-fork" ./emsdk/upstream/emscripten
+
+      - name: test
+        run: |
+          source ./emsdk/emsdk_env.sh
+          export EM_CONFIG="$EMSDK/.emscripten"
+          CARGO_TARGET_WASM32_UNKNOWN_EMSCRIPTEN_RUNNER="$JSPI_NODE" \
+          RUSTFLAGS="-A linker_messages -C target-feature=+atomics,+bulk-memory,+mutable-globals -C link-arg=-pthread -C link-arg=-sPROXY_TO_PTHREAD -C link-arg=-sNODERAWSOCKETS -C link-arg=-sNODERAWFS -C link-arg=-sALLOW_MEMORY_GROWTH=1 -C link-arg=-sEXIT_RUNTIME=1 -C link-arg=-sJSPI" \
+          cargo +nightly test --target wasm32-unknown-emscripten -Zbuild-std=std,panic_abort --test test \
+            --config 'patch.crates-io.libc.git="https://github.com/guybedford/libc"' \
+            --config 'patch.crates-io.libc.branch="libc-0.2-emscripten"'
+
+      - name: before_cache_script
+        run: rm -rf $CARGO_HOME/registry/index
+

README.md

@@ -103,6 +103,7 @@ The following targets are supported by `nix`:
     <li>x86_64-unknown-openbsd</li>
     <li>x86_64-unknown-redox</li>
     <li>i686-unknown-hurd-gnu</li>
+    <li>wasm32-unknown-emscripten</li>
    </td>
   </tr>
 </table>

src/sys/ioctl/linux.rs

@@ -5,6 +5,7 @@ use cfg_if::cfg_if;
     target_os = "android",
     target_os = "fuchsia",
     target_os = "cygwin",
+    target_os = "emscripten",
     target_env = "musl",
     target_env = "ohos"
 ))]
@@ -14,6 +15,7 @@ pub type ioctl_num_type = ::libc::c_int;
     target_os = "android",
     target_os = "fuchsia",
     target_os = "cygwin",
+    target_os = "emscripten",
     target_env = "musl",
     target_env = "ohos"
 )))]

src/sys/ioctl/mod.rs

@@ -231,7 +231,8 @@ use cfg_if::cfg_if;
     linux_android,
     target_os = "fuchsia",
     target_os = "redox",
-    target_os = "cygwin"
+    target_os = "cygwin",
+    target_os = "emscripten"
 ))]
 #[macro_use]
 mod linux;
@@ -240,7 +241,8 @@ mod linux;
     linux_android,
     target_os = "fuchsia",
     target_os = "redox",
-    target_os = "cygwin"
+    target_os = "cygwin",
+    target_os = "emscripten"
 ))]
 pub use self::linux::*;
 

src/sys/mod.rs

@@ -42,6 +42,7 @@ feature! {
     target_os = "haiku",
     target_os = "redox",
     target_os = "cygwin",
+    target_os = "emscripten",
 ))]
 #[cfg(feature = "ioctl")]
 #[cfg_attr(docsrs, doc(cfg(feature = "ioctl")))]

src/sys/resource.rs

@@ -21,6 +21,7 @@ cfg_if! {
         target_os = "aix",
         target_os = "illumos",
         all(target_os = "linux", not(target_env = "gnu")),
+        target_os = "emscripten",
         target_os = "cygwin"
     ))]{
         use libc::rlimit;
@@ -53,6 +54,7 @@ libc_enum! {
             target_os = "aix",
             target_os = "illumos",
             all(target_os = "linux", not(any(target_env = "gnu", target_env = "uclibc"))),
+            target_os = "emscripten",
             target_os = "cygwin"
         ), repr(i32))]
     #[non_exhaustive]

src/sys/socket/addr.rs

@@ -4,6 +4,7 @@
     solarish,
     target_os = "haiku",
     target_os = "fuchsia",
+    target_os = "emscripten",
     target_os = "aix",
 ))]
 #[cfg(feature = "net")]
@@ -448,6 +449,7 @@ impl UnixAddr {
                      target_os = "fuchsia",
                      solarish,
                      target_os = "redox",
+                     target_os = "emscripten",
                      target_os = "cygwin",
                 ))]
             {
@@ -513,6 +515,7 @@ impl UnixAddr {
                      target_os = "fuchsia",
                      solarish,
                      target_os = "redox",
+                     target_os = "emscripten",
                      target_os = "cygwin",
                 ))]
             {
@@ -531,6 +534,7 @@ impl SockaddrLike for UnixAddr {
         target_os = "fuchsia",
         solarish,
         target_os = "redox",
+        target_os = "emscripten",
         target_os = "cygwin",
     ))]
     fn len(&self) -> libc::socklen_t {
@@ -561,6 +565,7 @@ impl SockaddrLike for UnixAddr {
                          target_os = "fuchsia",
                          solarish,
                          target_os = "redox",
+                         target_os = "emscripten",
                          target_os = "cygwin",
                 ))] {
                 let su_len = len.unwrap_or(
@@ -1172,6 +1177,7 @@ impl SockaddrLike for SockaddrStorage {
                     linux_android,
                     target_os = "fuchsia",
                     solarish,
+                    target_os = "emscripten",
                     target_os = "cygwin",
                 ))]
                 if i32::from(ss.ss_family) == libc::AF_UNIX {
@@ -1229,7 +1235,7 @@ impl SockaddrLike for SockaddrStorage {
         }
     }
 
-    #[cfg(any(linux_android, target_os = "fuchsia", solarish, target_os = "cygwin"))]
+    #[cfg(any(linux_android, target_os = "fuchsia", solarish, target_os = "emscripten", target_os = "cygwin"))]
     fn len(&self) -> libc::socklen_t {
         match self.as_unix_addr() {
             // The UnixAddr type knows its own length
@@ -1291,6 +1297,7 @@ impl SockaddrStorage {
             if #[cfg(any(linux_android,
                      target_os = "fuchsia",
                      solarish,
+                     target_os = "emscripten",
                      target_os = "cygwin",
                 ))]
             {
@@ -1321,6 +1328,7 @@ impl SockaddrStorage {
             if #[cfg(any(linux_android,
                      target_os = "fuchsia",
                      solarish,
+                     target_os = "emscripten",
                      target_os = "cygwin",
                 ))]
             {
@@ -1834,7 +1842,7 @@ pub mod sys_control {
 }
 }
 
-#[cfg(any(linux_android, target_os = "fuchsia"))]
+#[cfg(any(linux_android, target_os = "fuchsia", target_os = "emscripten"))]
 mod datalink {
     feature! {
     #![feature = "net"]
@@ -2312,7 +2320,7 @@ mod tests {
         fn size() {
             #[cfg(any(bsd, target_os = "aix", solarish, target_os = "haiku"))]
             let l = mem::size_of::<libc::sockaddr_dl>();
-            #[cfg(any(linux_android, target_os = "fuchsia"))]
+            #[cfg(any(linux_android, target_os = "fuchsia", target_os = "emscripten"))]
             let l = mem::size_of::<libc::sockaddr_ll>();
             assert_eq!(LinkAddr::size() as usize, l);
         }

src/unistd.rs

@@ -1301,7 +1301,7 @@ feature! {
 /// On some systems, the host name is limited to as few as 64 bytes.  An error
 /// will be returned if the name is not valid or the current process does not
 /// have permissions to update the host name.
-#[cfg(not(target_os = "redox"))]
+#[cfg(not(any(target_os = "redox", target_os = "emscripten")))]
 pub fn sethostname<S: AsRef<OsStr>>(name: S) -> Result<()> {
     // Handle some differences in type of the len arg across platforms.
     cfg_if! {

test/sys/test_resource.rs

@@ -11,6 +11,7 @@ use nix::sys::resource::{getrusage, UsageWho};
 /// been updated.
 #[test]
 #[cfg_attr(target_os = "cygwin", ignore)]
+#[cfg_attr(target_os = "emscripten", ignore)]
 pub fn test_resource_limits_nofile() {
     let (mut soft_limit, hard_limit) =
         getrlimit(Resource::RLIMIT_NOFILE).unwrap();

test/sys/test_signal.rs

@@ -2,6 +2,7 @@ use nix::errno::Errno;
 use nix::sys::signal::*;
 use nix::unistd::*;
 use std::hash::{Hash, Hasher};
+#[cfg_attr(target_os = "emscripten", allow(unused_imports))]
 use std::sync::atomic::{AtomicBool, Ordering};
 #[cfg(not(target_os = "redox"))]
 use std::thread;
@@ -12,7 +13,7 @@ fn test_kill_none() {
 }
 
 #[test]
-#[cfg(not(target_os = "fuchsia"))]
+#[cfg(not(any(target_os = "fuchsia", target_os = "emscripten")))]
 fn test_killpg_none() {
     killpg(getpgrp(), None)
         .expect("Should be able to send signal to my process group.");
@@ -79,8 +80,10 @@ fn test_sigprocmask() {
         .expect("expect to be able to block signals");
 }
 
+#[cfg(not(target_os = "emscripten"))]
 static SIGNALED: AtomicBool = AtomicBool::new(false);
 
+#[cfg(not(target_os = "emscripten"))]
 extern "C" fn test_sigaction_handler(signal: libc::c_int) {
     let signal = Signal::try_from(signal).unwrap();
     SIGNALED.store(signal == Signal::SIGINT, Ordering::Relaxed);
@@ -107,6 +110,7 @@ fn test_signal_sigaction() {
 }
 
 #[test]
+#[cfg(not(target_os = "emscripten"))]
 fn test_signal() {
     let _m = crate::SIGNAL_MTX.lock();
 
@@ -186,7 +190,7 @@ fn test_extend() {
 }
 
 #[test]
-#[cfg(not(target_os = "redox"))]
+#[cfg(not(any(target_os = "redox", target_os = "emscripten")))]
 fn test_thread_signal_set_mask() {
     thread::spawn(|| {
         let prev_mask = SigSet::thread_get_mask()
@@ -211,7 +215,7 @@ fn test_thread_signal_set_mask() {
 }
 
 #[test]
-#[cfg(not(target_os = "redox"))]
+#[cfg(not(any(target_os = "redox", target_os = "emscripten")))]
 fn test_thread_signal_block() {
     thread::spawn(|| {
         let mut mask = SigSet::empty();
@@ -242,6 +246,7 @@ fn test_thread_signal_unblock() {
 
 #[test]
 #[cfg(not(target_os = "redox"))]
+#[cfg_attr(target_os = "emscripten", ignore)]
 fn test_thread_signal_swap() {
     thread::spawn(|| {
         let mut mask = SigSet::empty();

test/sys/test_socket.rs

@@ -286,6 +286,7 @@ pub fn test_unnamed_uds_addr() {
 }
 
 #[test]
+#[cfg_attr(target_os = "emscripten", ignore)]
 pub fn test_getsockname() {
     use nix::sys::socket::bind;
     use nix::sys::socket::{socket, AddressFamily, SockFlag, SockType};
@@ -308,6 +309,7 @@ pub fn test_getsockname() {
 }
 
 #[test]
+#[cfg_attr(target_os = "emscripten", ignore)]
 pub fn test_socketpair() {
     use nix::sys::socket::{socketpair, AddressFamily, SockFlag, SockType};
     use nix::unistd::{read, write};
@@ -328,6 +330,7 @@ pub fn test_socketpair() {
 
 #[test]
 #[cfg_attr(target_os = "cygwin", ignore)]
+#[cfg_attr(target_os = "emscripten", ignore)]
 pub fn test_recvmsg_sockaddr_un() {
     use nix::sys::socket::{
         self, bind, socket, AddressFamily, MsgFlags, SockFlag, SockType,
@@ -421,6 +424,7 @@ mod recvfrom {
     }
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     pub fn stream() {
         let (fd2, fd1) = socketpair(
             AddressFamily::Unix,
@@ -843,6 +847,7 @@ pub fn test_recvmsg_ebadf() {
 #[cfg_attr(qemu, ignore)]
 #[test]
 #[cfg_attr(target_os = "cygwin", ignore)]
+#[cfg_attr(target_os = "emscripten", ignore)]
 pub fn test_scm_rights() {
     use nix::sys::socket::{
         recvmsg, sendmsg, socketpair, AddressFamily, ControlMessage,
@@ -1346,6 +1351,7 @@ pub fn test_sendmsg_ipv4sendsrcaddr() {
 #[cfg_attr(qemu, ignore)]
 #[test]
 #[cfg_attr(target_os = "cygwin", ignore)]
+#[cfg_attr(target_os = "emscripten", ignore)]
 fn test_scm_rights_single_cmsg_multiple_fds() {
     use nix::sys::socket::{
         recvmsg, sendmsg, ControlMessage, ControlMessageOwned, MsgFlags,
@@ -1404,6 +1410,7 @@ fn test_scm_rights_single_cmsg_multiple_fds() {
 // msg_control field and a msg_controllen of 0 when calling into the
 // raw `sendmsg`.
 #[test]
+#[cfg_attr(target_os = "emscripten", ignore)]
 pub fn test_sendmsg_empty_cmsgs() {
     use nix::sys::socket::{
         recvmsg, sendmsg, socketpair, AddressFamily, MsgFlags, SockFlag,
@@ -3265,7 +3272,8 @@ fn can_use_cmsg_space() {
     linux_android,
     target_os = "redox",
     target_os = "haiku",
-    target_os = "cygwin"
+    target_os = "cygwin",
+    target_os = "emscripten"
 )))]
 #[test]
 fn can_open_routing_socket() {

test/sys/test_sockopt.rs

@@ -806,6 +806,7 @@ fn can_get_peerpidfd_on_unix_socket() {
 }
 
 #[test]
+#[cfg_attr(target_os = "emscripten", ignore)]
 fn is_socket_type_unix() {
     use nix::sys::socket::{socketpair, sockopt, SockFlag, SockType};
 

test/sys/test_termios.rs

@@ -26,6 +26,7 @@ fn test_baudrate_try_from() {
 
 // Test tcgetattr on a terminal
 #[test]
+#[cfg_attr(target_os = "emscripten", ignore)]
 fn test_tcgetattr_pty() {
     // openpty uses ptname(3) internally
     let _m = crate::PTSNAME_MTX.lock();
@@ -43,6 +44,7 @@ fn test_tcgetattr_enotty() {
 
 // Test modifying output flags
 #[test]
+#[cfg_attr(target_os = "emscripten", ignore)]
 fn test_output_flags() {
     // openpty uses ptname(3) internally
     let _m = crate::PTSNAME_MTX.lock();
@@ -81,6 +83,7 @@ fn test_output_flags() {
 // Test modifying local flags
 #[test]
 #[cfg(not(target_os = "solaris"))]
+#[cfg_attr(target_os = "emscripten", ignore)]
 fn test_local_flags() {
     // openpty uses ptname(3) internally
     let _m = crate::PTSNAME_MTX.lock();