added support for GNU/Hurd

21 files changed, 512 insertions, 27 deletions

diff --git a/library/std/build.rs b/library/std/build.rs
index a81c45609ea..e5509504b84 100644
--- a/library/std/build.rs
+++ b/library/std/build.rs
@@ -38,6 +38,7 @@ fn main() {
         || target.contains("vita")
         || target.contains("nto")
         || target.contains("xous")
+        || target.contains("hurd")
         // See src/bootstrap/synthetic_targets.rs
         || env::var("RUSTC_BOOTSTRAP_SYNTHETIC_TARGET").is_ok()
     {
diff --git a/library/std/src/os/hurd/fs.rs b/library/std/src/os/hurd/fs.rs
new file mode 100644
index 00000000000..00ff1560f31
--- /dev/null
+++ b/library/std/src/os/hurd/fs.rs
@@ -0,0 +1,348 @@
+//! Hurd-specific extensions to primitives in the [`std::fs`] module.
+//!
+//! [`std::fs`]: crate::fs
+
+#![stable(feature = "metadata_ext", since = "1.1.0")]
+
+use crate::fs::Metadata;
+use crate::sys_common::AsInner;
+
+/// OS-specific extensions to [`fs::Metadata`].
+///
+/// [`fs::Metadata`]: crate::fs::Metadata
+#[stable(feature = "metadata_ext", since = "1.1.0")]
+pub trait MetadataExt {
+    /// Returns the device ID on which this file resides.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_dev());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_dev(&self) -> u64;
+    /// Returns the inode number.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_ino());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_ino(&self) -> u64;
+    /// Returns the file type and mode.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_mode());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_mode(&self) -> u32;
+    /// Returns the number of hard links to file.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_nlink());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_nlink(&self) -> u64;
+    /// Returns the user ID of the file owner.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_uid());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_uid(&self) -> u32;
+    /// Returns the group ID of the file owner.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_gid());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_gid(&self) -> u32;
+    /// Returns the device ID that this file represents. Only relevant for special file.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_rdev());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_rdev(&self) -> u64;
+    /// Returns the size of the file (if it is a regular file or a symbolic link) in bytes.
+    ///
+    /// The size of a symbolic link is the length of the pathname it contains,
+    /// without a terminating null byte.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_size());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_size(&self) -> u64;
+    /// Returns the last access time of the file, in seconds since Unix Epoch.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_atime());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_atime(&self) -> i64;
+    /// Returns the last access time of the file, in nanoseconds since [`st_atime`].
+    ///
+    /// [`st_atime`]: Self::st_atime
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_atime_nsec());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_atime_nsec(&self) -> i64;
+    /// Returns the last modification time of the file, in seconds since Unix Epoch.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_mtime());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_mtime(&self) -> i64;
+    /// Returns the last modification time of the file, in nanoseconds since [`st_mtime`].
+    ///
+    /// [`st_mtime`]: Self::st_mtime
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_mtime_nsec());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_mtime_nsec(&self) -> i64;
+    /// Returns the last status change time of the file, in seconds since Unix Epoch.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_ctime());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_ctime(&self) -> i64;
+    /// Returns the last status change time of the file, in nanoseconds since [`st_ctime`].
+    ///
+    /// [`st_ctime`]: Self::st_ctime
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_ctime_nsec());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_ctime_nsec(&self) -> i64;
+    /// Returns the "preferred" block size for efficient filesystem I/O.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_blksize());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_blksize(&self) -> u64;
+    /// Returns the number of blocks allocated to the file, 512-byte units.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::hurd::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_blocks());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_blocks(&self) -> u64;
+}
+
+#[stable(feature = "metadata_ext", since = "1.1.0")]
+impl MetadataExt for Metadata {
+    fn st_dev(&self) -> u64 {
+        self.as_inner().as_inner().st_fsid as u64
+    }
+    fn st_ino(&self) -> u64 {
+        self.as_inner().as_inner().st_ino as u64
+    }
+    fn st_mode(&self) -> u32 {
+        self.as_inner().as_inner().st_mode as u32
+    }
+    fn st_nlink(&self) -> u64 {
+        self.as_inner().as_inner().st_nlink as u64
+    }
+    fn st_uid(&self) -> u32 {
+        self.as_inner().as_inner().st_uid as u32
+    }
+    fn st_gid(&self) -> u32 {
+        self.as_inner().as_inner().st_gid as u32
+    }
+    fn st_rdev(&self) -> u64 {
+        self.as_inner().as_inner().st_rdev as u64
+    }
+    fn st_size(&self) -> u64 {
+        self.as_inner().as_inner().st_size as u64
+    }
+    fn st_atime(&self) -> i64 {
+        self.as_inner().as_inner().st_atim.tv_sec as i64
+    }
+    fn st_atime_nsec(&self) -> i64 {
+        self.as_inner().as_inner().st_atim.tv_nsec as i64
+    }
+    fn st_mtime(&self) -> i64 {
+        self.as_inner().as_inner().st_mtim.tv_sec as i64
+    }
+    fn st_mtime_nsec(&self) -> i64 {
+        self.as_inner().as_inner().st_mtim.tv_nsec as i64
+    }
+    fn st_ctime(&self) -> i64 {
+        self.as_inner().as_inner().st_ctim.tv_sec as i64
+    }
+    fn st_ctime_nsec(&self) -> i64 {
+        self.as_inner().as_inner().st_ctim.tv_nsec as i64
+    }
+    fn st_blksize(&self) -> u64 {
+        self.as_inner().as_inner().st_blksize as u64
+    }
+    fn st_blocks(&self) -> u64 {
+        self.as_inner().as_inner().st_blocks as u64
+    }
+}
diff --git a/library/std/src/os/hurd/mod.rs b/library/std/src/os/hurd/mod.rs
new file mode 100644
index 00000000000..aee86c7f616
--- /dev/null
+++ b/library/std/src/os/hurd/mod.rs
@@ -0,0 +1,6 @@
+//! Hurd-specific definitions
+
+#![stable(feature = "raw_ext", since = "1.1.0")]
+
+pub mod fs;
+pub mod raw;
diff --git a/library/std/src/os/hurd/raw.rs b/library/std/src/os/hurd/raw.rs
new file mode 100644
index 00000000000..fa266663528
--- /dev/null
+++ b/library/std/src/os/hurd/raw.rs
@@ -0,0 +1,33 @@
+//! Hurd-specific raw type definitions
+
+#![stable(feature = "raw_ext", since = "1.1.0")]
+#![deprecated(
+    since = "1.8.0",
+    note = "these type aliases are no longer supported by \
+              the standard library, the `libc` crate on \
+              crates.io should be used instead for the correct \
+              definitions"
+)]
+#![allow(deprecated)]
+
+use crate::os::raw::{c_long, c_uint, c_ulong};
+
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type blkcnt_t = u64;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type blksize_t = c_long;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type dev_t = c_ulong;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type ino_t = u64;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type mode_t = c_uint;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type nlink_t = c_ulong;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type off_t = u64;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type time_t = c_long;
+
+#[stable(feature = "pthread_t", since = "1.8.0")]
+pub type pthread_t = c_long;
diff --git a/library/std/src/os/mod.rs b/library/std/src/os/mod.rs
index de6d784c65b..24d16e64c86 100644
--- a/library/std/src/os/mod.rs
+++ b/library/std/src/os/mod.rs
@@ -117,6 +117,8 @@ pub mod haiku;
 pub mod hermit;
 #[cfg(target_os = "horizon")]
 pub mod horizon;
+#[cfg(target_os = "hurd")]
+pub mod hurd;
 #[cfg(target_os = "illumos")]
 pub mod illumos;
 #[cfg(target_os = "ios")]
diff --git a/library/std/src/os/unix/mod.rs b/library/std/src/os/unix/mod.rs
index 401ec1e7a01..3724e90afbd 100644
--- a/library/std/src/os/unix/mod.rs
+++ b/library/std/src/os/unix/mod.rs
@@ -53,6 +53,8 @@ mod platform {
     pub use crate::os::haiku::*;
     #[cfg(target_os = "horizon")]
     pub use crate::os::horizon::*;
+    #[cfg(target_os = "hurd")]
+    pub use crate::os::hurd::*;
     #[cfg(target_os = "illumos")]
     pub use crate::os::illumos::*;
     #[cfg(target_os = "ios")]
diff --git a/library/std/src/sys/unix/args.rs b/library/std/src/sys/unix/args.rs
index eafd6821f54..19334e2aff2 100644
--- a/library/std/src/sys/unix/args.rs
+++ b/library/std/src/sys/unix/args.rs
@@ -71,6 +71,7 @@ impl DoubleEndedIterator for Args {
     target_os = "vxworks",
     target_os = "horizon",
     target_os = "nto",
+    target_os = "hurd",
 ))]
 mod imp {
     use super::Args;
diff --git a/library/std/src/sys/unix/env.rs b/library/std/src/sys/unix/env.rs
index 929e9dae738..c6d8578a629 100644
--- a/library/std/src/sys/unix/env.rs
+++ b/library/std/src/sys/unix/env.rs
@@ -152,6 +152,17 @@ pub mod os {
     pub const EXE_EXTENSION: &str = "elf";
 }
 
+#[cfg(target_os = "hurd")]
+pub mod os {
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "hurd";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
+}
+
 #[cfg(target_os = "vita")]
 pub mod os {
     pub const FAMILY: &str = "unix";
diff --git a/library/std/src/sys/unix/fd.rs b/library/std/src/sys/unix/fd.rs
index 85e020ae413..6c4f408426a 100644
--- a/library/std/src/sys/unix/fd.rs
+++ b/library/std/src/sys/unix/fd.rs
@@ -13,14 +13,16 @@ use crate::sys_common::{AsInner, FromInner, IntoInner};
     target_os = "android",
     target_os = "linux",
     target_os = "emscripten",
-    target_os = "l4re"
+    target_os = "l4re",
+    target_os = "hurd",
 ))]
 use libc::off64_t;
 #[cfg(not(any(
     target_os = "linux",
     target_os = "emscripten",
     target_os = "l4re",
-    target_os = "android"
+    target_os = "android",
+    target_os = "hurd",
 )))]
 use libc::off_t as off64_t;
 
@@ -124,9 +126,9 @@ impl FileDesc {
     }
 
     pub fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
-        #[cfg(not(any(target_os = "linux", target_os = "android")))]
+        #[cfg(not(any(target_os = "linux", target_os = "android", target_os = "hurd")))]
         use libc::pread as pread64;
-        #[cfg(any(target_os = "linux", target_os = "android"))]
+        #[cfg(any(target_os = "linux", target_os = "android", target_os = "hurd"))]
         use libc::pread64;
 
         unsafe {
@@ -160,6 +162,7 @@ impl FileDesc {
         target_os = "emscripten",
         target_os = "freebsd",
         target_os = "fuchsia",
+        target_os = "hurd",
         target_os = "illumos",
         target_os = "linux",
         target_os = "netbsd",
@@ -181,6 +184,7 @@ impl FileDesc {
         target_os = "emscripten",
         target_os = "freebsd",
         target_os = "fuchsia",
+        target_os = "hurd",
         target_os = "illumos",
         target_os = "ios",
         target_os = "tvos",
@@ -281,9 +285,9 @@ impl FileDesc {
     }
 
     pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
-        #[cfg(not(any(target_os = "linux", target_os = "android")))]
+        #[cfg(not(any(target_os = "linux", target_os = "android", target_os = "hurd")))]
         use libc::pwrite as pwrite64;
-        #[cfg(any(target_os = "linux", target_os = "android"))]
+        #[cfg(any(target_os = "linux", target_os = "android", target_os = "hurd"))]
         use libc::pwrite64;
 
         unsafe {
@@ -301,6 +305,7 @@ impl FileDesc {
         target_os = "emscripten",
         target_os = "freebsd",
         target_os = "fuchsia",
+        target_os = "hurd",
         target_os = "illumos",
         target_os = "linux",
         target_os = "netbsd",
@@ -322,6 +327,7 @@ impl FileDesc {
         target_os = "emscripten",
         target_os = "freebsd",
         target_os = "fuchsia",
+        target_os = "hurd",
         target_os = "illumos",
         target_os = "ios",
         target_os = "tvos",
diff --git a/library/std/src/sys/unix/fs.rs b/library/std/src/sys/unix/fs.rs
index 61ea87a5b0c..764e1f25790 100644
--- a/library/std/src/sys/unix/fs.rs
+++ b/library/std/src/sys/unix/fs.rs
@@ -39,9 +39,14 @@ use libc::{c_int, mode_t};
     all(target_os = "linux", target_env = "gnu")
 ))]
 use libc::c_char;
-#[cfg(any(target_os = "linux", target_os = "emscripten", target_os = "android"))]
+#[cfg(any(
+    target_os = "linux",
+    target_os = "emscripten",
+    target_os = "android",
+    target_os = "hurd",
+))]
 use libc::dirfd;
-#[cfg(any(target_os = "linux", target_os = "emscripten"))]
+#[cfg(any(target_os = "linux", target_os = "emscripten", target_os = "hurd"))]
 use libc::fstatat64;
 #[cfg(any(
     target_os = "android",
@@ -53,7 +58,7 @@ use libc::fstatat64;
     target_os = "vita",
 ))]
 use libc::readdir as readdir64;
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "linux", target_os = "hurd"))]
 use libc::readdir64;
 #[cfg(any(target_os = "emscripten", target_os = "l4re"))]
 use libc::readdir64_r;
@@ -68,6 +73,7 @@ use libc::readdir64_r;
     target_os = "redox",
     target_os = "nto",
     target_os = "vita",
+    target_os = "hurd",
 )))]
 use libc::readdir_r as readdir64_r;
 #[cfg(target_os = "android")]
@@ -79,13 +85,19 @@ use libc::{
     target_os = "linux",
     target_os = "emscripten",
     target_os = "l4re",
-    target_os = "android"
+    target_os = "android",
+    target_os = "hurd",
 )))]
 use libc::{
     dirent as dirent64, fstat as fstat64, ftruncate as ftruncate64, lseek as lseek64,
     lstat as lstat64, off_t as off64_t, open as open64, stat as stat64,
 };
-#[cfg(any(target_os = "linux", target_os = "emscripten", target_os = "l4re"))]
+#[cfg(any(
+    target_os = "linux",
+    target_os = "emscripten",
+    target_os = "l4re",
+    target_os = "hurd"
+))]
 use libc::{dirent64, fstat64, ftruncate64, lseek64, lstat64, off64_t, open64, stat64};
 
 pub use crate::sys_common::fs::try_exists;
@@ -277,7 +289,8 @@ unsafe impl Sync for Dir {}
     target_os = "fuchsia",
     target_os = "redox",
     target_os = "nto",
-    target_os = "vita"
+    target_os = "vita",
+    target_os = "hurd",
 ))]
 pub struct DirEntry {
     dir: Arc<InnerReadDir>,
@@ -300,6 +313,7 @@ pub struct DirEntry {
     target_os = "redox",
     target_os = "nto",
     target_os = "vita",
+    target_os = "hurd",
 ))]
 struct dirent64_min {
     d_ino: u64,
@@ -321,6 +335,7 @@ struct dirent64_min {
     target_os = "redox",
     target_os = "nto",
     target_os = "vita",
+    target_os = "hurd",
 )))]
 pub struct DirEntry {
     dir: Arc<InnerReadDir>,
@@ -455,7 +470,8 @@ impl FileAttr {
         target_os = "vxworks",
         target_os = "espidf",
         target_os = "horizon",
-        target_os = "vita"
+        target_os = "vita",
+        target_os = "hurd",
     )))]
     pub fn modified(&self) -> io::Result<SystemTime> {
         #[cfg(target_pointer_width = "32")]
@@ -473,7 +489,7 @@ impl FileAttr {
         Ok(SystemTime::new(self.stat.st_mtime as i64, 0))
     }
 
-    #[cfg(target_os = "horizon")]
+    #[cfg(any(target_os = "horizon", target_os = "hurd"))]
     pub fn modified(&self) -> io::Result<SystemTime> {
         Ok(SystemTime::from(self.stat.st_mtim))
     }
@@ -482,7 +498,8 @@ impl FileAttr {
         target_os = "vxworks",
         target_os = "espidf",
         target_os = "horizon",
-        target_os = "vita"
+        target_os = "vita",
+        target_os = "hurd",
     )))]
     pub fn accessed(&self) -> io::Result<SystemTime> {
         #[cfg(target_pointer_width = "32")]
@@ -500,7 +517,7 @@ impl FileAttr {
         Ok(SystemTime::new(self.stat.st_atime as i64, 0))
     }
 
-    #[cfg(target_os = "horizon")]
+    #[cfg(any(target_os = "horizon", target_os = "hurd"))]
     pub fn accessed(&self) -> io::Result<SystemTime> {
         Ok(SystemTime::from(self.stat.st_atim))
     }
@@ -656,6 +673,7 @@ impl Iterator for ReadDir {
         target_os = "illumos",
         target_os = "nto",
         target_os = "vita",
+        target_os = "hurd",
     ))]
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
         if self.end_of_stream {
@@ -756,6 +774,7 @@ impl Iterator for ReadDir {
         target_os = "illumos",
         target_os = "nto",
         target_os = "vita",
+        target_os = "hurd",
     )))]
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
         if self.end_of_stream {
@@ -809,7 +828,12 @@ impl DirEntry {
     }
 
     #[cfg(all(
-        any(target_os = "linux", target_os = "emscripten", target_os = "android"),
+        any(
+            target_os = "linux",
+            target_os = "emscripten",
+            target_os = "android",
+            target_os = "hurd",
+        ),
         not(miri)
     ))]
     pub fn metadata(&self) -> io::Result<FileAttr> {
@@ -833,7 +857,12 @@ impl DirEntry {
     }
 
     #[cfg(any(
-        not(any(target_os = "linux", target_os = "emscripten", target_os = "android")),
+        not(any(
+            target_os = "linux",
+            target_os = "emscripten",
+            target_os = "android",
+            target_os = "hurd",
+        )),
         miri
     ))]
     pub fn metadata(&self) -> io::Result<FileAttr> {
@@ -892,6 +921,7 @@ impl DirEntry {
         target_os = "horizon",
         target_os = "vita",
         target_os = "nto",
+        target_os = "hurd",
     ))]
     pub fn ino(&self) -> u64 {
         self.entry.d_ino as u64
@@ -949,6 +979,7 @@ impl DirEntry {
         target_os = "redox",
         target_os = "nto",
         target_os = "vita",
+        target_os = "hurd",
     )))]
     fn name_cstr(&self) -> &CStr {
         unsafe { CStr::from_ptr(self.entry.d_name.as_ptr()) }
@@ -962,6 +993,7 @@ impl DirEntry {
         target_os = "redox",
         target_os = "nto",
         target_os = "vita",
+        target_os = "hurd",
     ))]
     fn name_cstr(&self) -> &CStr {
         &self.name
@@ -1131,6 +1163,7 @@ impl File {
             target_os = "netbsd",
             target_os = "openbsd",
             target_os = "nto",
+            target_os = "hurd",
         ))]
         unsafe fn os_datasync(fd: c_int) -> c_int {
             libc::fdatasync(fd)
@@ -1146,6 +1179,7 @@ impl File {
             target_os = "openbsd",
             target_os = "watchos",
             target_os = "nto",
+            target_os = "hurd",
         )))]
         unsafe fn os_datasync(fd: c_int) -> c_int {
             libc::fsync(fd)
@@ -1456,6 +1490,7 @@ impl fmt::Debug for File {
             target_os = "linux",
             target_os = "macos",
             target_os = "freebsd",
+            target_os = "hurd",
             target_os = "netbsd",
             target_os = "openbsd",
             target_os = "vxworks"
@@ -1477,6 +1512,7 @@ impl fmt::Debug for File {
             target_os = "linux",
             target_os = "macos",
             target_os = "freebsd",
+            target_os = "hurd",
             target_os = "netbsd",
             target_os = "openbsd",
             target_os = "vxworks"
diff --git a/library/std/src/sys/unix/kernel_copy.rs b/library/std/src/sys/unix/kernel_copy.rs
index 4d17a1b0002..18acd5ecccd 100644
--- a/library/std/src/sys/unix/kernel_copy.rs
+++ b/library/std/src/sys/unix/kernel_copy.rs
@@ -59,9 +59,9 @@ use crate::ptr;
 use crate::sync::atomic::{AtomicBool, AtomicU8, Ordering};
 use crate::sys::cvt;
 use crate::sys::weak::syscall;
-#[cfg(not(all(target_os = "linux", target_env = "gnu")))]
+#[cfg(not(any(all(target_os = "linux", target_env = "gnu"), target_os = "hurd")))]
 use libc::sendfile as sendfile64;
-#[cfg(all(target_os = "linux", target_env = "gnu"))]
+#[cfg(any(all(target_os = "linux", target_env = "gnu"), target_os = "hurd"))]
 use libc::sendfile64;
 use libc::{EBADF, EINVAL, ENOSYS, EOPNOTSUPP, EOVERFLOW, EPERM, EXDEV};
 
diff --git a/library/std/src/sys/unix/mod.rs b/library/std/src/sys/unix/mod.rs
index 692d3ab7cc9..3edafde71e9 100644
--- a/library/std/src/sys/unix/mod.rs
+++ b/library/std/src/sys/unix/mod.rs
@@ -204,6 +204,10 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
             }
             if let Some(handler) = handler {
                 rtassert!(signal(libc::SIGPIPE, handler) != libc::SIG_ERR);
+                #[cfg(target_os = "hurd")]
+                {
+                    rtassert!(signal(libc::SIGLOST, handler) != libc::SIG_ERR);
+                }
             }
         }
     }
diff --git a/library/std/src/sys/unix/net.rs b/library/std/src/sys/unix/net.rs
index 48f163b6db0..f450d708dae 100644
--- a/library/std/src/sys/unix/net.rs
+++ b/library/std/src/sys/unix/net.rs
@@ -75,6 +75,7 @@ impl Socket {
                     target_os = "dragonfly",
                     target_os = "freebsd",
                     target_os = "illumos",
+                    target_os = "hurd",
                     target_os = "linux",
                     target_os = "netbsd",
                     target_os = "openbsd",
@@ -114,6 +115,7 @@ impl Socket {
                     target_os = "freebsd",
                     target_os = "illumos",
                     target_os = "linux",
+                    target_os = "hurd",
                     target_os = "netbsd",
                     target_os = "openbsd",
                     target_os = "nto",
@@ -220,6 +222,7 @@ impl Socket {
                 target_os = "freebsd",
                 target_os = "illumos",
                 target_os = "linux",
+                target_os = "hurd",
                 target_os = "netbsd",
                 target_os = "openbsd",
             ))] {
diff --git a/library/std/src/sys/unix/os.rs b/library/std/src/sys/unix/os.rs
index 57e1a36dace..01ff375d215 100644
--- a/library/std/src/sys/unix/os.rs
+++ b/library/std/src/sys/unix/os.rs
@@ -46,7 +46,8 @@ extern "C" {
             target_os = "linux",
             target_os = "emscripten",
             target_os = "fuchsia",
-            target_os = "l4re"
+            target_os = "l4re",
+            target_os = "hurd",
         ),
         link_name = "__errno_location"
     )]
@@ -121,7 +122,10 @@ pub fn set_errno(e: i32) {
 pub fn error_string(errno: i32) -> String {
     extern "C" {
         #[cfg_attr(
-            all(any(target_os = "linux", target_env = "newlib"), not(target_env = "ohos")),
+            all(
+                any(target_os = "linux", target_os = "hurd", target_env = "newlib"),
+                not(target_env = "ohos")
+            ),
             link_name = "__xpg_strerror_r"
         )]
         fn strerror_r(errnum: c_int, buf: *mut c_char, buflen: libc::size_t) -> c_int;
@@ -359,7 +363,12 @@ pub fn current_exe() -> io::Result<PathBuf> {
     }
 }
 
-#[cfg(any(target_os = "linux", target_os = "android", target_os = "emscripten"))]
+#[cfg(any(
+    target_os = "linux",
+    target_os = "hurd",
+    target_os = "android",
+    target_os = "emscripten"
+))]
 pub fn current_exe() -> io::Result<PathBuf> {
     match crate::fs::read_link("/proc/self/exe") {
         Err(ref e) if e.kind() == io::ErrorKind::NotFound => Err(io::const_io_error!(
diff --git a/library/std/src/sys/unix/pipe.rs b/library/std/src/sys/unix/pipe.rs
index 938a46bfdd8..1239c65a483 100644
--- a/library/std/src/sys/unix/pipe.rs
+++ b/library/std/src/sys/unix/pipe.rs
@@ -21,6 +21,7 @@ pub fn anon_pipe() -> io::Result<(AnonPipe, AnonPipe)> {
         if #[cfg(any(
             target_os = "dragonfly",
             target_os = "freebsd",
+            target_os = "hurd",
             target_os = "linux",
             target_os = "netbsd",
             target_os = "openbsd",
diff --git a/library/std/src/sys/unix/process/process_unix.rs b/library/std/src/sys/unix/process/process_unix.rs
index 75b54064501..564f8c48290 100644
--- a/library/std/src/sys/unix/process/process_unix.rs
+++ b/library/std/src/sys/unix/process/process_unix.rs
@@ -374,6 +374,13 @@ impl Command {
                         return Err(io::Error::last_os_error());
                     }
                 }
+                #[cfg(target_os = "hurd")]
+                {
+                    let ret = sys::signal(libc::SIGLOST, libc::SIG_DFL);
+                    if ret == libc::SIG_ERR {
+                        return Err(io::Error::last_os_error());
+                    }
+                }
             }
         }
 
@@ -620,6 +627,10 @@ impl Command {
                 let mut default_set = MaybeUninit::<libc::sigset_t>::uninit();
                 cvt(sigemptyset(default_set.as_mut_ptr()))?;
                 cvt(sigaddset(default_set.as_mut_ptr(), libc::SIGPIPE))?;
+                #[cfg(target_os = "hurd")]
+                {
+                    cvt(sigaddset(default_set.as_mut_ptr(), libc::SIGLOST))?;
+                }
                 cvt_nz(libc::posix_spawnattr_setsigdefault(
                     attrs.0.as_mut_ptr(),
                     default_set.as_ptr(),
@@ -993,6 +1004,8 @@ fn signal_string(signal: i32) -> &'static str {
             target_os = "dragonfly"
         ))]
         libc::SIGINFO => " (SIGINFO)",
+        #[cfg(target_os = "hurd")]
+        libc::SIGLOST => " (SIGLOST)",
         _ => "",
     }
 }
diff --git a/library/std/src/sys/unix/stack_overflow.rs b/library/std/src/sys/unix/stack_overflow.rs
index b59d4ba26af..73c530786b2 100644
--- a/library/std/src/sys/unix/stack_overflow.rs
+++ b/library/std/src/sys/unix/stack_overflow.rs
@@ -32,6 +32,7 @@ impl Drop for Handler {
     target_os = "macos",
     target_os = "dragonfly",
     target_os = "freebsd",
+    target_os = "hurd",
     target_os = "solaris",
     target_os = "illumos",
     target_os = "netbsd",
@@ -193,6 +194,7 @@ mod imp {
     target_os = "macos",
     target_os = "dragonfly",
     target_os = "freebsd",
+    target_os = "hurd",
     target_os = "solaris",
     target_os = "illumos",
     target_os = "netbsd",
diff --git a/library/std/src/sys/unix/thread.rs b/library/std/src/sys/unix/thread.rs
index 7c242d4d334..3631a5bbabd 100644
--- a/library/std/src/sys/unix/thread.rs
+++ b/library/std/src/sys/unix/thread.rs
@@ -216,7 +216,8 @@ impl Thread {
         target_os = "l4re",
         target_os = "emscripten",
         target_os = "redox",
-        target_os = "vxworks"
+        target_os = "vxworks",
+        target_os = "hurd",
     ))]
     pub fn set_name(_name: &CStr) {
         // Newlib, Emscripten, and VxWorks have no way to set a thread name.
@@ -309,6 +310,7 @@ pub fn available_parallelism() -> io::Result<NonZeroUsize> {
             target_os = "android",
             target_os = "emscripten",
             target_os = "fuchsia",
+            target_os = "hurd",
             target_os = "ios",
             target_os = "tvos",
             target_os = "linux",
@@ -690,6 +692,7 @@ mod cgroups {
 #[cfg(all(
     not(target_os = "linux"),
     not(target_os = "freebsd"),
+    not(target_os = "hurd"),
     not(target_os = "macos"),
     not(target_os = "netbsd"),
     not(target_os = "openbsd"),
@@ -710,6 +713,7 @@ pub mod guard {
 #[cfg(any(
     target_os = "linux",
     target_os = "freebsd",
+    target_os = "hurd",
     target_os = "macos",
     target_os = "netbsd",
     target_os = "openbsd",
@@ -766,6 +770,7 @@ pub mod guard {
     #[cfg(any(
         target_os = "android",
         target_os = "freebsd",
+        target_os = "hurd",
         target_os = "linux",
         target_os = "netbsd",
         target_os = "l4re"
@@ -903,6 +908,7 @@ pub mod guard {
     #[cfg(any(
         target_os = "android",
         target_os = "freebsd",
+        target_os = "hurd",
         target_os = "linux",
         target_os = "netbsd",
         target_os = "l4re"
@@ -934,7 +940,7 @@ pub mod guard {
             assert_eq!(libc::pthread_attr_getstack(&attr, &mut stackptr, &mut size), 0);
 
             let stackaddr = stackptr.addr();
-            ret = if cfg!(any(target_os = "freebsd", target_os = "netbsd")) {
+            ret = if cfg!(any(target_os = "freebsd", target_os = "netbsd", target_os = "hurd")) {
                 Some(stackaddr - guardsize..stackaddr)
             } else if cfg!(all(target_os = "linux", target_env = "musl")) {
                 Some(stackaddr - guardsize..stackaddr)
diff --git a/library/std/src/sys/unix/thread_local_dtor.rs b/library/std/src/sys/unix/thread_local_dtor.rs
index 236d2f2ee29..1da41d4b4bf 100644
--- a/library/std/src/sys/unix/thread_local_dtor.rs
+++ b/library/std/src/sys/unix/thread_local_dtor.rs
@@ -11,7 +11,7 @@
 // Note, however, that we run on lots older linuxes, as well as cross
 // compiling from a newer linux to an older linux, so we also have a
 // fallback implementation to use as well.
-#[cfg(any(target_os = "linux", target_os = "fuchsia", target_os = "redox"))]
+#[cfg(any(target_os = "linux", target_os = "fuchsia", target_os = "redox", target_os = "hurd"))]
 pub unsafe fn register_dtor(t: *mut u8, dtor: unsafe extern "C" fn(*mut u8)) {
     use crate::mem;
     use crate::sys_common::thread_local_dtor::register_dtor_fallback;
diff --git a/library/std/src/sys/unix/time.rs b/library/std/src/sys/unix/time.rs
index 17b4130c202..4fe61b28488 100644
--- a/library/std/src/sys/unix/time.rs
+++ b/library/std/src/sys/unix/time.rs
@@ -35,7 +35,7 @@ pub(in crate::sys::unix) struct Timespec {
 }
 
 impl SystemTime {
-    #[cfg_attr(target_os = "horizon", allow(unused))]
+    #[cfg_attr(any(target_os = "horizon", target_os = "hurd"), allow(unused))]
     pub fn new(tv_sec: i64, tv_nsec: i64) -> SystemTime {
         SystemTime { t: Timespec::new(tv_sec, tv_nsec) }
     }
diff --git a/library/std/src/sys_common/net.rs b/library/std/src/sys_common/net.rs
index 2976a9f578e..4f5b17deaa2 100644
--- a/library/std/src/sys_common/net.rs
+++ b/library/std/src/sys_common/net.rs
@@ -32,6 +32,7 @@ cfg_if::cfg_if! {
 cfg_if::cfg_if! {
     if #[cfg(any(
         target_os = "linux", target_os = "android",
+        target_os = "hurd",
         target_os = "dragonfly", target_os = "freebsd",
         target_os = "openbsd", target_os = "netbsd",
         target_os = "haiku", target_os = "nto"))] {