Add support and CI tests for BSDs

This adds a fallback using `shm_open`/`shm_unlink` for platforms where
`memfd_create` doesn't exist. This seems to be how this is normally
handled, though it's a bit ugly.

This also builds the wayland/x11 code for NetBSD/OpenBSD/DragonFlyBSD.

Add CI builds for FreeBSD and NetBSD. We would need some kind of
virtualisation though to actually run tests on such targets.

I've tested the `shm_open` logic on Linux, but haven't run it on any
BSDs.

.github/workflows/ci.yml

@@ -33,6 +33,8 @@ jobs:
           - { target: x86_64-unknown-linux-gnu, os: ubuntu-latest, options: --no-default-features, features: x11 }
           - { target: x86_64-unknown-linux-gnu, os: ubuntu-latest, options: --no-default-features, features: "wayland,wayland-dlopen" }
           - { target: x86_64-unknown-redox,     os: ubuntu-latest,   }
+          - { target: x86_64-unknown-freebsd,   os: ubuntu-latest,   }
+          - { target: x86_64-unknown-netbsd,    os: ubuntu-latest,   }
           - { target: x86_64-apple-darwin,      os: macos-latest,    }
           # We're using Windows rather than Ubuntu to run the wasm tests because caching cargo-web
           # doesn't currently work on Linux.
@@ -77,6 +79,8 @@ jobs:
       if: >
         !((matrix.platform.os == 'ubuntu-latest') && contains(matrix.platform.target, 'i686')) &&
         !contains(matrix.platform.target, 'redox') &&
+        !contains(matrix.platform.target, 'freebsd') &&
+        !contains(matrix.platform.target, 'netbsd') &&
         matrix.rust_version != '1.60.0'
       run: cargo $CMD test --no-run --verbose --target ${{ matrix.platform.target }} $OPTIONS --features $FEATURES
 
@@ -85,7 +89,9 @@ jobs:
       if: >
         !((matrix.platform.os == 'ubuntu-latest') && contains(matrix.platform.target, 'i686')) &&
         !contains(matrix.platform.target, 'wasm32') &&
-        !contains(matrix.platform.target, 'redox')
+        !contains(matrix.platform.target, 'redox') &&
+        !contains(matrix.platform.target, 'freebsd') &&
+        !contains(matrix.platform.target, 'netbsd')
       run: cargo $CMD test --verbose --target ${{ matrix.platform.target }} $OPTIONS --features $FEATURES
 
     - name: Lint with clippy
@@ -94,5 +100,7 @@ jobs:
         (matrix.rust_version == 'stable') &&
         !contains(matrix.platform.options, '--no-default-features') &&
         !((matrix.platform.os == 'ubuntu-latest') && contains(matrix.platform.target, 'i686')) &&
-        !contains(matrix.platform.target, 'redox')
+        !contains(matrix.platform.target, 'redox') &&
+        !contains(matrix.platform.target, 'freebsd') &&
+        !contains(matrix.platform.target, 'netbsd')
       run: cargo clippy --all-targets --target ${{ matrix.platform.target }} $OPTIONS --features $FEATURES -- -Dwarnings

Cargo.toml

@@ -14,7 +14,7 @@ rust-version = "1.60.0"
 
 [features]
 default = ["x11", "wayland", "wayland-dlopen"]
-wayland = ["wayland-backend", "wayland-client", "nix"]
+wayland = ["wayland-backend", "wayland-client", "nix", "fastrand"]
 wayland-dlopen = ["wayland-sys/dlopen"]
 x11 = ["bytemuck", "x11rb", "x11-dl"]
 
@@ -23,7 +23,7 @@ thiserror = "1.0.30"
 raw-window-handle = "0.5.0"
 log = "0.4.17"
 
-[target.'cfg(any(target_os = "linux", target_os = "freebsd"))'.dependencies]
+[target.'cfg(any(target_os = "linux", target_os = "freebsd", target_os = "dragonfly", target_os = "netbsd", target_os = "openbsd"))'.dependencies]
 nix = { version = "0.26.1", optional = true }
 wayland-backend = { version = "0.1.0", features = ["client_system"], optional = true }
 wayland-client = { version = "0.30.0", optional = true }
@@ -32,6 +32,9 @@ bytemuck = { version = "1.12.3", optional = true }
 x11-dl = { version  = "2.19.1", optional = true }
 x11rb = { version = "0.11.0", features = ["allow-unsafe-code", "dl-libxcb"], optional = true }
 
+[target.'cfg(any(target_os = "dragonfly", target_os = "netbsd", target_os = "openbsd"))'.dependencies]
+fastrand = { version = "1.8.0", optional = true }
+
 [target.'cfg(target_os = "windows")'.dependencies.windows-sys]
 version = "0.42.0"
 features = ["Win32_Graphics_Gdi", "Win32_UI_WindowsAndMessaging", "Win32_Foundation"]

src/lib.rs

@@ -10,13 +10,31 @@ extern crate core;
 mod cg;
 #[cfg(target_os = "redox")]
 mod orbital;
-#[cfg(all(feature = "wayland", any(target_os = "linux", target_os = "freebsd")))]
+#[cfg(all(
+    feature = "wayland",
+    any(
+        target_os = "linux",
+        target_os = "freebsd",
+        target_os = "dragonfly",
+        target_os = "netbsd",
+        target_os = "openbsd"
+    )
+))]
 mod wayland;
 #[cfg(target_arch = "wasm32")]
 mod web;
 #[cfg(target_os = "windows")]
 mod win32;
-#[cfg(all(feature = "x11", any(target_os = "linux", target_os = "freebsd")))]
+#[cfg(all(
+    feature = "x11",
+    any(
+        target_os = "linux",
+        target_os = "freebsd",
+        target_os = "dragonfly",
+        target_os = "netbsd",
+        target_os = "openbsd"
+    )
+))]
 mod x11;
 
 mod error;
@@ -66,9 +84,9 @@ macro_rules! make_dispatch {
 }
 
 make_dispatch! {
-    #[cfg(all(feature = "x11", any(target_os = "linux", target_os = "freebsd")))]
+    #[cfg(all(feature = "x11", any(target_os = "linux", target_os = "freebsd", target_os = "dragonfly", target_os = "netbsd", target_os = "openbsd")))]
     X11(x11::X11Impl),
-    #[cfg(all(feature = "wayland", any(target_os = "linux", target_os = "freebsd")))]
+    #[cfg(all(feature = "wayland", any(target_os = "linux", target_os = "freebsd", target_os = "dragonfly", target_os = "netbsd", target_os = "openbsd")))]
     Wayland(wayland::WaylandImpl),
     #[cfg(target_os = "windows")]
     Win32(win32::Win32Impl),
@@ -105,21 +123,48 @@ impl GraphicsContext {
         raw_display_handle: RawDisplayHandle,
     ) -> Result<Self, SoftBufferError> {
         let imple: Dispatch = match (raw_window_handle, raw_display_handle) {
-            #[cfg(all(feature = "x11", any(target_os = "linux", target_os = "freebsd")))]
+            #[cfg(all(
+                feature = "x11",
+                any(
+                    target_os = "linux",
+                    target_os = "freebsd",
+                    target_os = "dragonfly",
+                    target_os = "netbsd",
+                    target_os = "openbsd"
+                )
+            ))]
             (
                 RawWindowHandle::Xlib(xlib_window_handle),
                 RawDisplayHandle::Xlib(xlib_display_handle),
             ) => Dispatch::X11(unsafe {
                 x11::X11Impl::from_xlib(xlib_window_handle, xlib_display_handle)?
             }),
-            #[cfg(all(feature = "x11", any(target_os = "linux", target_os = "freebsd")))]
+            #[cfg(all(
+                feature = "x11",
+                any(
+                    target_os = "linux",
+                    target_os = "freebsd",
+                    target_os = "dragonfly",
+                    target_os = "netbsd",
+                    target_os = "openbsd"
+                )
+            ))]
             (
                 RawWindowHandle::Xcb(xcb_window_handle),
                 RawDisplayHandle::Xcb(xcb_display_handle),
             ) => Dispatch::X11(unsafe {
                 x11::X11Impl::from_xcb(xcb_window_handle, xcb_display_handle)?
             }),
-            #[cfg(all(feature = "wayland", any(target_os = "linux", target_os = "freebsd")))]
+            #[cfg(all(
+                feature = "wayland",
+                any(
+                    target_os = "linux",
+                    target_os = "freebsd",
+                    target_os = "dragonfly",
+                    target_os = "netbsd",
+                    target_os = "openbsd"
+                )
+            ))]
             (
                 RawWindowHandle::Wayland(wayland_window_handle),
                 RawDisplayHandle::Wayland(wayland_display_handle),

src/wayland/buffer.rs

@@ -1,4 +1,3 @@
-use nix::sys::memfd::{memfd_create, MemFdCreateFlag};
 use std::{
     ffi::CStr,
     fs::File,
@@ -15,6 +14,50 @@ use wayland_client::{
 
 use super::State;
 
+#[cfg(any(target_os = "linux", target_os = "freebsd"))]
+fn create_memfile() -> File {
+    use nix::sys::memfd::{memfd_create, MemFdCreateFlag};
+
+    let name = unsafe { CStr::from_bytes_with_nul_unchecked("softbuffer\0".as_bytes()) };
+    let fd = memfd_create(name, MemFdCreateFlag::MFD_CLOEXEC)
+        .expect("Failed to create memfd to store buffer.");
+    unsafe { File::from_raw_fd(fd) }
+}
+
+#[cfg(not(any(target_os = "linux", target_os = "freebsd")))]
+fn create_memfile() -> File {
+    use nix::{
+        errno::Errno,
+        fcntl::OFlag,
+        sys::{
+            mman::{shm_open, shm_unlink},
+            stat::Mode,
+        },
+    };
+    use std::iter;
+
+    for _ in 0..=4 {
+        let mut name = String::from("softbuffer-");
+        name.extend(iter::repeat_with(fastrand::alphanumeric).take(7));
+        name.push('\0');
+
+        let name = unsafe { CStr::from_bytes_with_nul_unchecked(name.as_bytes()) };
+        // `CLOEXEC` is implied with `shm_open`
+        let fd = shm_open(
+            name,
+            OFlag::O_RDWR | OFlag::O_CREAT | OFlag::O_EXCL,
+            Mode::S_IRWXU,
+        );
+        if fd != Err(Errno::EEXIST) {
+            let fd = fd.expect("Failed to create POSIX shm to store buffer.");
+            let _ = shm_unlink(name);
+            return unsafe { File::from_raw_fd(fd) };
+        }
+    }
+
+    panic!("Failed to generate non-existant shm name")
+}
+
 pub(super) struct WaylandBuffer {
     qh: QueueHandle<State>,
     tempfile: File,
@@ -28,10 +71,7 @@ pub(super) struct WaylandBuffer {
 
 impl WaylandBuffer {
     pub fn new(shm: &wl_shm::WlShm, width: i32, height: i32, qh: &QueueHandle<State>) -> Self {
-        let name = unsafe { CStr::from_bytes_with_nul_unchecked("softbuffer\0".as_bytes()) };
+        let tempfile = create_memfile();
-        let tempfile_fd = memfd_create(name, MemFdCreateFlag::MFD_CLOEXEC)
-            .expect("Failed to create memfd to store buffer.");
-        let tempfile = unsafe { File::from_raw_fd(tempfile_fd) };
         let pool_size = width * height * 4;
         let pool = shm.create_pool(tempfile.as_raw_fd(), pool_size, qh, ());
         let released = Arc::new(AtomicBool::new(true));