Add GNU/Hurd support (#852)

Author: sthibaul

src/backend/libc/fs/dir.rs

@@ -20,9 +20,9 @@ use crate::io;
 #[cfg(not(any(target_os = "fuchsia", target_os = "wasi")))]
 use crate::process::fchdir;
 use alloc::borrow::ToOwned;
-#[cfg(not(linux_like))]
+#[cfg(not(any(linux_like, target_os = "hurd")))]
 use c::readdir as libc_readdir;
-#[cfg(linux_like)]
+#[cfg(any(linux_like, target_os = "hurd"))]
 use c::readdir64 as libc_readdir;
 use core::fmt;
 use core::ptr::NonNull;

src/backend/libc/fs/syscalls.rs

@@ -122,7 +122,7 @@ weak!(fn __futimens64(c::c_int, *const LibcTimespec) -> c::c_int);
 /// Use a direct syscall (via libc) for `openat`.
 ///
 /// This is only currently necessary as a workaround for old glibc; see below.
-#[cfg(all(unix, target_env = "gnu"))]
+#[cfg(all(unix, target_env = "gnu", not(target_os = "hurd")))]
 fn openat_via_syscall(
     dirfd: BorrowedFd<'_>,
     path: &CStr,
@@ -153,7 +153,7 @@ pub(crate) fn openat(
 ) -> io::Result<OwnedFd> {
     // Work around <https://sourceware.org/bugzilla/show_bug.cgi?id=17523>.
     // glibc versions before 2.25 don't handle `O_TMPFILE` correctly.
-    #[cfg(all(unix, target_env = "gnu"))]
+    #[cfg(all(unix, target_env = "gnu", not(target_os = "hurd")))]
     if oflags.contains(OFlags::TMPFILE) && crate::backend::if_glibc_is_less_than_2_25() {
         return openat_via_syscall(dirfd, path, oflags, mode);
     }

src/backend/libc/fs/types.rs

@@ -274,6 +274,7 @@ bitflags! {
             target_os = "android",
             target_os = "emscripten",
             target_os = "fuchsia",
+            target_os = "hurd",
             target_os = "linux",
         ))]
         const TMPFILE = c::O_TMPFILE;
@@ -717,6 +718,7 @@ bitflags! {
             bsd,
             target_os = "aix",
             target_os = "haiku",
+            target_os = "hurd",
             target_os = "wasi",
         )))]
         const KEEP_SIZE = c::FALLOC_FL_KEEP_SIZE;
@@ -725,6 +727,7 @@ bitflags! {
             bsd,
             target_os = "aix",
             target_os = "haiku",
+            target_os = "hurd",
             target_os = "wasi",
         )))]
         const PUNCH_HOLE = c::FALLOC_FL_PUNCH_HOLE;
@@ -733,6 +736,7 @@ bitflags! {
             bsd,
             target_os = "aix",
             target_os = "haiku",
+            target_os = "hurd",
             target_os = "linux",
             target_os = "emscripten",
             target_os = "fuchsia",
@@ -744,6 +748,7 @@ bitflags! {
             bsd,
             target_os = "aix",
             target_os = "haiku",
+            target_os = "hurd",
             target_os = "emscripten",
             target_os = "wasi",
         )))]
@@ -753,6 +758,7 @@ bitflags! {
             bsd,
             target_os = "aix",
             target_os = "haiku",
+            target_os = "hurd",
             target_os = "emscripten",
             target_os = "wasi",
         )))]
@@ -762,6 +768,7 @@ bitflags! {
             bsd,
             target_os = "aix",
             target_os = "haiku",
+            target_os = "hurd",
             target_os = "emscripten",
             target_os = "wasi",
         )))]
@@ -771,6 +778,7 @@ bitflags! {
             bsd,
             target_os = "aix",
             target_os = "haiku",
+            target_os = "hurd",
             target_os = "emscripten",
             target_os = "wasi",
         )))]
@@ -844,7 +852,7 @@ pub enum FlockOperation {
 ///
 /// [`statat`]: crate::fs::statat
 /// [`fstat`]: crate::fs::fstat
-#[cfg(not(linux_like))]
+#[cfg(not(any(linux_like, target_os = "hurd")))]
 pub type Stat = c::stat;
 
 /// `struct stat` for use with [`statat`] and [`fstat`].
@@ -853,6 +861,7 @@ pub type Stat = c::stat;
 /// [`fstat`]: crate::fs::fstat
 #[cfg(any(
     all(linux_kernel, target_pointer_width = "64"),
+    target_os = "hurd",
     target_os = "emscripten",
     target_os = "l4re",
 ))]