Update for nightly-2018-08-18

16 files changed, 241 insertions, 110 deletions

diff --git a/ctr-std/src/sys/unix/args.rs b/ctr-std/src/sys/unix/args.rs
index e1c7ffc..c3c033d 100644
--- a/ctr-std/src/sys/unix/args.rs
+++ b/ctr-std/src/sys/unix/args.rs
@@ -66,7 +66,8 @@ impl DoubleEndedIterator for Args {
           target_os = "emscripten",
           target_os = "haiku",
           target_os = "l4re",
-          target_os = "fuchsia"))]
+          target_os = "fuchsia",
+          target_os = "hermit"))]
 mod imp {
     use os::unix::prelude::*;
     use ptr;
@@ -79,20 +80,20 @@ mod imp {
 
     static mut ARGC: isize = 0;
     static mut ARGV: *const *const u8 = ptr::null();
+    // We never call `ENV_LOCK.init()`, so it is UB to attempt to
+    // acquire this mutex reentrantly!
     static LOCK: Mutex = Mutex::new();
 
     pub unsafe fn init(argc: isize, argv: *const *const u8) {
-        LOCK.lock();
+        let _guard = LOCK.lock();
         ARGC = argc;
         ARGV = argv;
-        LOCK.unlock();
     }
 
     pub unsafe fn cleanup() {
-        LOCK.lock();
+        let _guard = LOCK.lock();
         ARGC = 0;
         ARGV = ptr::null();
-        LOCK.unlock();
     }
 
     pub fn args() -> Args {
@@ -104,13 +105,11 @@ mod imp {
 
     fn clone() -> Vec<OsString> {
         unsafe {
-            LOCK.lock();
-            let ret = (0..ARGC).map(|i| {
+            let _guard = LOCK.lock();
+            (0..ARGC).map(|i| {
                 let cstr = CStr::from_ptr(*ARGV.offset(i) as *const libc::c_char);
                 OsStringExt::from_vec(cstr.to_bytes().to_vec())
-            }).collect();
-            LOCK.unlock();
-            return ret
+            }).collect()
         }
     }
 }
diff --git a/ctr-std/src/sys/unix/backtrace/tracing/gcc_s.rs b/ctr-std/src/sys/unix/backtrace/tracing/gcc_s.rs
index 1b92fc0..6e84156 100644
--- a/ctr-std/src/sys/unix/backtrace/tracing/gcc_s.rs
+++ b/ctr-std/src/sys/unix/backtrace/tracing/gcc_s.rs
@@ -68,6 +68,10 @@ pub fn unwind_backtrace(frames: &mut [Frame])
 extern fn trace_fn(ctx: *mut uw::_Unwind_Context,
                    arg: *mut libc::c_void) -> uw::_Unwind_Reason_Code {
     let cx = unsafe { &mut *(arg as *mut Context) };
+    if cx.idx >= cx.frames.len() {
+        return uw::_URC_NORMAL_STOP;
+    }
+
     let mut ip_before_insn = 0;
     let mut ip = unsafe {
         uw::_Unwind_GetIPInfo(ctx, &mut ip_before_insn) as *mut libc::c_void
@@ -94,14 +98,12 @@ extern fn trace_fn(ctx: *mut uw::_Unwind_Context,
         unsafe { uw::_Unwind_FindEnclosingFunction(ip) }
     };
 
-    if cx.idx < cx.frames.len() {
-        cx.frames[cx.idx] = Frame {
-            symbol_addr: symaddr as *mut u8,
-            exact_position: ip as *mut u8,
-            inline_context: 0,
-        };
-        cx.idx += 1;
-    }
+    cx.frames[cx.idx] = Frame {
+        symbol_addr: symaddr as *mut u8,
+        exact_position: ip as *mut u8,
+        inline_context: 0,
+    };
+    cx.idx += 1;
 
     uw::_URC_NO_REASON
 }
diff --git a/ctr-std/src/sys/unix/condvar.rs b/ctr-std/src/sys/unix/condvar.rs
index 4f878d8..2007da7 100644
--- a/ctr-std/src/sys/unix/condvar.rs
+++ b/ctr-std/src/sys/unix/condvar.rs
@@ -41,13 +41,15 @@ impl Condvar {
     #[cfg(any(target_os = "macos",
               target_os = "ios",
               target_os = "l4re",
-              target_os = "android"))]
+              target_os = "android",
+              target_os = "hermit"))]
     pub unsafe fn init(&mut self) {}
 
     #[cfg(not(any(target_os = "macos",
                   target_os = "ios",
                   target_os = "l4re",
-                  target_os = "android")))]
+                  target_os = "android",
+                  target_os = "hermit")))]
     pub unsafe fn init(&mut self) {
         use mem;
         let mut attr: libc::pthread_condattr_t = mem::uninitialized();
@@ -83,7 +85,10 @@ impl Condvar {
     // where we configure condition variable to use monotonic clock (instead of
     // default system clock). This approach avoids all problems that result
     // from changes made to the system time.
-    #[cfg(not(any(target_os = "macos", target_os = "ios", target_os = "android")))]
+    #[cfg(not(any(target_os = "macos",
+                  target_os = "ios",
+                  target_os = "android",
+                  target_os = "hermit")))]
     pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
         use mem;
 
@@ -113,7 +118,7 @@ impl Condvar {
     // This implementation is modeled after libcxx's condition_variable
     // https://github.com/llvm-mirror/libcxx/blob/release_35/src/condition_variable.cpp#L46
     // https://github.com/llvm-mirror/libcxx/blob/release_35/include/__mutex_base#L367
-    #[cfg(any(target_os = "macos", target_os = "ios", target_os = "android"))]
+    #[cfg(any(target_os = "macos", target_os = "ios", target_os = "android", target_os = "hermit"))]
     pub unsafe fn wait_timeout(&self, mutex: &Mutex, mut dur: Duration) -> bool {
         use ptr;
         use time::Instant;
diff --git a/ctr-std/src/sys/unix/env.rs b/ctr-std/src/sys/unix/env.rs
index 00cf7ec..ad116c5 100644
--- a/ctr-std/src/sys/unix/env.rs
+++ b/ctr-std/src/sys/unix/env.rs
@@ -172,3 +172,14 @@ pub mod os {
     pub const EXE_SUFFIX: &'static str = "";
     pub const EXE_EXTENSION: &'static str = "";
 }
+
+#[cfg(target_os = "hermit")]
+pub mod os {
+    pub const FAMILY: &'static str = "unix";
+    pub const OS: &'static str = "hermit";
+    pub const DLL_PREFIX: &'static str = "lib";
+    pub const DLL_SUFFIX: &'static str = ".so";
+    pub const DLL_EXTENSION: &'static str = "so";
+    pub const EXE_SUFFIX: &'static str = "";
+    pub const EXE_EXTENSION: &'static str = "";
+}
diff --git a/ctr-std/src/sys/unix/ext/fs.rs b/ctr-std/src/sys/unix/ext/fs.rs
index 4e98101..507e9d8 100644
--- a/ctr-std/src/sys/unix/ext/fs.rs
+++ b/ctr-std/src/sys/unix/ext/fs.rs
@@ -59,6 +59,78 @@ pub trait FileExt {
     #[stable(feature = "file_offset", since = "1.15.0")]
     fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize>;
 
+    /// Reads the exact number of byte required to fill `buf` from the given offset.
+    ///
+    /// The offset is relative to the start of the file and thus independent
+    /// from the current cursor.
+    ///
+    /// The current file cursor is not affected by this function.
+    ///
+    /// Similar to [`Read::read_exact`] but uses [`read_at`] instead of `read`.
+    ///
+    /// [`Read::read_exact`]: ../../../../std/io/trait.Read.html#method.read_exact
+    /// [`read_at`]: #tymethod.read_at
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// [`ErrorKind::Interrupted`] then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind [`ErrorKind::UnexpectedEof`].
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// [`ErrorKind::Interrupted`]: ../../../../std/io/enum.ErrorKind.html#variant.Interrupted
+    /// [`ErrorKind::UnexpectedEof`]: ../../../../std/io/enum.ErrorKind.html#variant.UnexpectedEof
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(rw_exact_all_at)]
+    /// use std::io;
+    /// use std::fs::File;
+    /// use std::os::unix::prelude::FileExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let mut buf = [0u8; 8];
+    ///     let file = File::open("foo.txt")?;
+    ///
+    ///     // We now read exactly 8 bytes from the offset 10.
+    ///     file.read_exact_at(&mut buf, 10)?;
+    ///     println!("read {} bytes: {:?}", buf.len(), buf);
+    ///     Ok(())
+    /// }
+    /// ```
+    #[unstable(feature = "rw_exact_all_at", issue = "51984")]
+    fn read_exact_at(&self, mut buf: &mut [u8], mut offset: u64) -> io::Result<()> {
+        while !buf.is_empty() {
+            match self.read_at(buf, offset) {
+                Ok(0) => break,
+                Ok(n) => {
+                    let tmp = buf;
+                    buf = &mut tmp[n..];
+                    offset += n as u64;
+                }
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(io::Error::new(io::ErrorKind::UnexpectedEof,
+                               "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
     /// Writes a number of bytes starting from a given offset.
     ///
     /// Returns the number of bytes written.
@@ -93,6 +165,61 @@ pub trait FileExt {
     /// ```
     #[stable(feature = "file_offset", since = "1.15.0")]
     fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize>;
+
+    /// Attempts to write an entire buffer starting from a given offset.
+    ///
+    /// The offset is relative to the start of the file and thus independent
+    /// from the current cursor.
+    ///
+    /// The current file cursor is not affected by this function.
+    ///
+    /// This method will continuously call [`write_at`] until there is no more data
+    /// to be written or an error of non-[`ErrorKind::Interrupted`] kind is
+    /// returned. This method will not return until the entire buffer has been
+    /// successfully written or such an error occurs. The first error that is
+    /// not of [`ErrorKind::Interrupted`] kind generated from this method will be
+    /// returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error of
+    /// non-[`ErrorKind::Interrupted`] kind that [`write_at`] returns.
+    ///
+    /// [`ErrorKind::Interrupted`]: ../../../../std/io/enum.ErrorKind.html#variant.Interrupted
+    /// [`write_at`]: #tymethod.write_at
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(rw_exact_all_at)]
+    /// use std::fs::File;
+    /// use std::io;
+    /// use std::os::unix::prelude::FileExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let file = File::open("foo.txt")?;
+    ///
+    ///     // We now write at the offset 10.
+    ///     file.write_all_at(b"sushi", 10)?;
+    ///     Ok(())
+    /// }
+    /// ```
+    #[unstable(feature = "rw_exact_all_at", issue = "51984")]
+    fn write_all_at(&self, mut buf: &[u8], mut offset: u64) -> io::Result<()> {
+        while !buf.is_empty() {
+            match self.write_at(buf, offset) {
+                Ok(0) => return Err(io::Error::new(io::ErrorKind::WriteZero,
+                                                   "failed to write whole buffer")),
+                Ok(n) => {
+                    buf = &buf[n..];
+                    offset += n as u64
+                }
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
 }
 
 #[stable(feature = "file_offset", since = "1.15.0")]
diff --git a/ctr-std/src/sys/unix/ext/mod.rs b/ctr-std/src/sys/unix/ext/mod.rs
index c221f7c..88e4237 100644
--- a/ctr-std/src/sys/unix/ext/mod.rs
+++ b/ctr-std/src/sys/unix/ext/mod.rs
@@ -35,6 +35,7 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 #![doc(cfg(unix))]
+#![allow(missing_docs)]
 
 pub mod io;
 pub mod ffi;
diff --git a/ctr-std/src/sys/unix/ext/net.rs b/ctr-std/src/sys/unix/ext/net.rs
index e277b1a..55f43cc 100644
--- a/ctr-std/src/sys/unix/ext/net.rs
+++ b/ctr-std/src/sys/unix/ext/net.rs
@@ -524,6 +524,9 @@ impl UnixStream {
     ///     println!("Got error: {:?}", err);
     /// }
     /// ```
+    ///
+    /// # Platform specific
+    /// On Redox this always returns None.
     #[stable(feature = "unix_socket", since = "1.10.0")]
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         self.0.take_error()
@@ -846,6 +849,9 @@ impl UnixListener {
     ///     println!("Got error: {:?}", err);
     /// }
     /// ```
+    ///
+    /// # Platform specific
+    /// On Redox this always returns None.
     #[stable(feature = "unix_socket", since = "1.10.0")]
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         self.0.take_error()
diff --git a/ctr-std/src/sys/unix/fast_thread_local.rs b/ctr-std/src/sys/unix/fast_thread_local.rs
index 6cdbe5d..c13a0fe 100644
--- a/ctr-std/src/sys/unix/fast_thread_local.rs
+++ b/ctr-std/src/sys/unix/fast_thread_local.rs
@@ -20,7 +20,7 @@
 // fallback implementation to use as well.
 //
 // Due to rust-lang/rust#18804, make sure this is not generic!
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "linux", target_os = "fuchsia", target_os = "hermit"))]
 pub unsafe fn register_dtor(t: *mut u8, dtor: unsafe extern fn(*mut u8)) {
     use libc;
     use mem;
@@ -55,11 +55,6 @@ pub unsafe fn register_dtor(t: *mut u8, dtor: unsafe extern fn(*mut u8)) {
     _tlv_atexit(dtor, t);
 }
 
-// Just use the thread_local fallback implementation, at least until there's
-// a more direct implementation.
-#[cfg(target_os = "fuchsia")]
-pub use sys_common::thread_local::register_dtor_fallback as register_dtor;
-
 pub fn requires_move_before_drop() -> bool {
     // The macOS implementation of TLS apparently had an odd aspect to it
     // where the pointer we have may be overwritten while this destructor
diff --git a/ctr-std/src/sys/unix/fs.rs b/ctr-std/src/sys/unix/fs.rs
index 7743403..7a89d98 100644
--- a/ctr-std/src/sys/unix/fs.rs
+++ b/ctr-std/src/sys/unix/fs.rs
@@ -25,10 +25,12 @@ use sys_common::{AsInner, FromInner};
 
 #[cfg(any(target_os = "linux", target_os = "emscripten", target_os = "l4re"))]
 use libc::{stat64, fstat64, lstat64, off64_t, ftruncate64, lseek64, dirent64, readdir64_r, open64};
+#[cfg(any(target_os = "linux", target_os = "emscripten"))]
+use libc::fstatat64;
 #[cfg(any(target_os = "linux", target_os = "emscripten", target_os = "android"))]
-use libc::{fstatat, dirfd};
+use libc::dirfd;
 #[cfg(target_os = "android")]
-use libc::{stat as stat64, fstat as fstat64, lstat as lstat64, lseek64,
+use libc::{stat as stat64, fstat as fstat64, fstatat as fstatat64, lstat as lstat64, lseek64,
            dirent as dirent64, open as open64};
 #[cfg(not(any(target_os = "linux",
               target_os = "emscripten",
@@ -57,7 +59,10 @@ struct InnerReadDir {
 }
 
 #[derive(Clone)]
-pub struct ReadDir(Arc<InnerReadDir>);
+pub struct ReadDir {
+    inner: Arc<InnerReadDir>,
+    end_of_stream: bool,
+}
 
 struct Dir(*mut libc::DIR);
 
@@ -213,7 +218,7 @@ impl fmt::Debug for ReadDir {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         // This will only be called from std::fs::ReadDir, which will add a "ReadDir()" frame.
         // Thus the result will be e g 'ReadDir("/home")'
-        fmt::Debug::fmt(&*self.0.root, f)
+        fmt::Debug::fmt(&*self.inner.root, f)
     }
 }
 
@@ -229,7 +234,7 @@ impl Iterator for ReadDir {
                 // is safe to use in threaded applications and it is generally preferred
                 // over the readdir_r(3C) function.
                 super::os::set_errno(0);
-                let entry_ptr = libc::readdir(self.0.dirp.0);
+                let entry_ptr = libc::readdir(self.inner.dirp.0);
                 if entry_ptr.is_null() {
                     // NULL can mean either the end is reached or an error occurred.
                     // So we had to clear errno beforehand to check for an error now.
@@ -257,6 +262,10 @@ impl Iterator for ReadDir {
 
     #[cfg(not(any(target_os = "solaris", target_os = "fuchsia")))]
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
+        if self.end_of_stream {
+            return None;
+        }
+
         unsafe {
             let mut ret = DirEntry {
                 entry: mem::zeroed(),
@@ -264,7 +273,14 @@ impl Iterator for ReadDir {
             };
             let mut entry_ptr = ptr::null_mut();
             loop {
-                if readdir64_r(self.0.dirp.0, &mut ret.entry, &mut entry_ptr) != 0 {
+                if readdir64_r(self.inner.dirp.0, &mut ret.entry, &mut entry_ptr) != 0 {
+                    if entry_ptr.is_null() {
+                        // We encountered an error (which will be returned in this iteration), but
+                        // we also reached the end of the directory stream. The `end_of_stream`
+                        // flag is enabled to make sure that we return `None` in the next iteration
+                        // (instead of looping forever)
+                        self.end_of_stream = true;
+                    }
                     return Some(Err(Error::last_os_error()))
                 }
                 if entry_ptr.is_null() {
@@ -287,7 +303,7 @@ impl Drop for Dir {
 
 impl DirEntry {
     pub fn path(&self) -> PathBuf {
-        self.dir.0.root.join(OsStr::from_bytes(self.name_bytes()))
+        self.dir.inner.root.join(OsStr::from_bytes(self.name_bytes()))
     }
 
     pub fn file_name(&self) -> OsString {
@@ -296,13 +312,10 @@ impl DirEntry {
 
     #[cfg(any(target_os = "linux", target_os = "emscripten", target_os = "android"))]
     pub fn metadata(&self) -> io::Result<FileAttr> {
-        let fd = cvt(unsafe {dirfd(self.dir.0.dirp.0)})?;
+        let fd = cvt(unsafe {dirfd(self.dir.inner.dirp.0)})?;
         let mut stat: stat64 = unsafe { mem::zeroed() };
         cvt(unsafe {
-            fstatat(fd,
-                    self.entry.d_name.as_ptr(),
-                    &mut stat as *mut _ as *mut _,
-                    libc::AT_SYMLINK_NOFOLLOW)
+            fstatat64(fd, self.entry.d_name.as_ptr(), &mut stat, libc::AT_SYMLINK_NOFOLLOW)
         })?;
         Ok(FileAttr { stat: stat })
     }
@@ -312,12 +325,12 @@ impl DirEntry {
         lstat(&self.path())
     }
 
-    #[cfg(any(target_os = "solaris", target_os = "haiku"))]
+    #[cfg(any(target_os = "solaris", target_os = "haiku", target_os = "hermit"))]
     pub fn file_type(&self) -> io::Result<FileType> {
         lstat(&self.path()).map(|m| m.file_type())
     }
 
-    #[cfg(not(any(target_os = "solaris", target_os = "haiku")))]
+    #[cfg(not(any(target_os = "solaris", target_os = "haiku", target_os = "hermit")))]
     pub fn file_type(&self) -> io::Result<FileType> {
         match self.entry.d_type {
             libc::DT_CHR => Ok(FileType { mode: libc::S_IFCHR }),
@@ -339,7 +352,8 @@ impl DirEntry {
               target_os = "solaris",
               target_os = "haiku",
               target_os = "l4re",
-              target_os = "fuchsia"))]
+              target_os = "fuchsia",
+              target_os = "hermit"))]
     pub fn ino(&self) -> u64 {
         self.entry.d_ino as u64
     }
@@ -370,7 +384,8 @@ impl DirEntry {
               target_os = "linux",
               target_os = "emscripten",
               target_os = "l4re",
-              target_os = "haiku"))]
+              target_os = "haiku",
+              target_os = "hermit"))]
     fn name_bytes(&self) -> &[u8] {
         unsafe {
             CStr::from_ptr(self.entry.d_name.as_ptr()).to_bytes()
@@ -692,7 +707,10 @@ pub fn readdir(p: &Path) -> io::Result<ReadDir> {
             Err(Error::last_os_error())
         } else {
             let inner = InnerReadDir { dirp: Dir(ptr), root };
-            Ok(ReadDir(Arc::new(inner)))
+            Ok(ReadDir{
+                inner: Arc::new(inner),
+                end_of_stream: false,
+            })
         }
     }
 }
@@ -787,7 +805,7 @@ pub fn stat(p: &Path) -> io::Result<FileAttr> {
     let p = cstr(p)?;
     let mut stat: stat64 = unsafe { mem::zeroed() };
     cvt(unsafe {
-        stat64(p.as_ptr(), &mut stat as *mut _ as *mut _)
+        stat64(p.as_ptr(), &mut stat)
     })?;
     Ok(FileAttr { stat: stat })
 }
@@ -796,7 +814,7 @@ pub fn lstat(p: &Path) -> io::Result<FileAttr> {
     let p = cstr(p)?;
     let mut stat: stat64 = unsafe { mem::zeroed() };
     cvt(unsafe {
-        lstat64(p.as_ptr(), &mut stat as *mut _ as *mut _)
+        lstat64(p.as_ptr(), &mut stat)
     })?;
     Ok(FileAttr { stat: stat })
 }
diff --git a/ctr-std/src/sys/unix/mod.rs b/ctr-std/src/sys/unix/mod.rs
index c1298e5..c738003 100644
--- a/ctr-std/src/sys/unix/mod.rs
+++ b/ctr-std/src/sys/unix/mod.rs
@@ -28,6 +28,7 @@ use libc;
 #[cfg(all(not(dox), target_os = "emscripten"))] pub use os::emscripten as platform;
 #[cfg(all(not(dox), target_os = "fuchsia"))]   pub use os::fuchsia as platform;
 #[cfg(all(not(dox), target_os = "l4re"))]      pub use os::linux as platform;
+#[cfg(all(not(dox), target_os = "hermit"))]    pub use os::hermit as platform;
 
 pub use self::rand::hashmap_random_keys;
 pub use libc::strlen;
diff --git a/ctr-std/src/sys/unix/mutex.rs b/ctr-std/src/sys/unix/mutex.rs
index 52cf3f9..1d447de 100644
--- a/ctr-std/src/sys/unix/mutex.rs
+++ b/ctr-std/src/sys/unix/mutex.rs
@@ -25,8 +25,10 @@ unsafe impl Sync for Mutex {}
 #[allow(dead_code)] // sys isn't exported yet
 impl Mutex {
     pub const fn new() -> Mutex {
-        // Might be moved and address is changing it is better to avoid
-        // initialization of potentially opaque OS data before it landed
+        // Might be moved to a different address, so it is better to avoid
+        // initialization of potentially opaque OS data before it landed.
+        // Be very careful using this newly constructed `Mutex`, reentrant
+        // locking is undefined behavior until `init` is called!
         Mutex { inner: UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER) }
     }
     #[inline]
@@ -49,9 +51,6 @@ impl Mutex {
         // references, we instead create the mutex with type
         // PTHREAD_MUTEX_NORMAL which is guaranteed to deadlock if we try to
         // re-lock it from the same thread, thus avoiding undefined behavior.
-        //
-        // We can't do anything for StaticMutex, but that type is deprecated
-        // anyways.
         let mut attr: libc::pthread_mutexattr_t = mem::uninitialized();
         let r = libc::pthread_mutexattr_init(&mut attr);
         debug_assert_eq!(r, 0);
diff --git a/ctr-std/src/sys/unix/os.rs b/ctr-std/src/sys/unix/os.rs
index 4c86fdd..f8f0bbd 100644
--- a/ctr-std/src/sys/unix/os.rs
+++ b/ctr-std/src/sys/unix/os.rs
@@ -33,6 +33,8 @@ use sys::fd;
 use vec;
 
 const TMPBUF_SZ: usize = 128;
+// We never call `ENV_LOCK.init()`, so it is UB to attempt to
+// acquire this mutex reentrantly!
 static ENV_LOCK: Mutex = Mutex::new();
 
 
@@ -47,6 +49,7 @@ extern {
                    target_os = "netbsd",
                    target_os = "openbsd",
                    target_os = "android",
+                   target_os = "hermit",
                    target_env = "newlib"),
                link_name = "__errno")]
     #[cfg_attr(target_os = "solaris", link_name = "___errno")]
@@ -376,7 +379,7 @@ pub fn current_exe() -> io::Result<PathBuf> {
     }
 }
 
-#[cfg(any(target_os = "fuchsia", target_os = "l4re"))]
+#[cfg(any(target_os = "fuchsia", target_os = "l4re", target_os = "hermit"))]
 pub fn current_exe() -> io::Result<PathBuf> {
     use io::ErrorKind;
     Err(io::Error::new(ErrorKind::Other, "Not yet implemented!"))
@@ -409,26 +412,19 @@ pub unsafe fn environ() -> *mut *const *const c_char {
 /// environment variables of the current process.
 pub fn env() -> Env {
     unsafe {
-        ENV_LOCK.lock();
+        let _guard = ENV_LOCK.lock();
         let mut environ = *environ();
-        if environ == ptr::null() {
-            ENV_LOCK.unlock();
-            panic!("os::env() failure getting env string from OS: {}",
-                   io::Error::last_os_error());
-        }
         let mut result = Vec::new();
-        while *environ != ptr::null() {
+        while environ != ptr::null() && *environ != ptr::null() {
             if let Some(key_value) = parse(CStr::from_ptr(*environ).to_bytes()) {
                 result.push(key_value);
             }
             environ = environ.offset(1);
         }
-        let ret = Env {
+        return Env {
             iter: result.into_iter(),
             _dont_send_or_sync_me: PhantomData,
-        };
-        ENV_LOCK.unlock();
-        return ret
+        }
     }
 
     fn parse(input: &[u8]) -> Option<(OsString, OsString)> {
@@ -452,15 +448,14 @@ pub fn getenv(k: &OsStr) -> io::Result<Option<OsString>> {
     // always None as well
     let k = CString::new(k.as_bytes())?;
     unsafe {
-        ENV_LOCK.lock();
+        let _guard = ENV_LOCK.lock();
         let s = libc::getenv(k.as_ptr()) as *const libc::c_char;
         let ret = if s.is_null() {
             None
         } else {
             Some(OsStringExt::from_vec(CStr::from_ptr(s).to_bytes().to_vec()))
         };
-        ENV_LOCK.unlock();
-        return Ok(ret)
+        Ok(ret)
     }
 }
 
@@ -469,10 +464,8 @@ pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     let v = CString::new(v.as_bytes())?;
 
     unsafe {
-        ENV_LOCK.lock();
-        let ret = cvt(libc::setenv(k.as_ptr(), v.as_ptr(), 1)).map(|_| ());
-        ENV_LOCK.unlock();
-        return ret
+        let _guard = ENV_LOCK.lock();
+        cvt(libc::setenv(k.as_ptr(), v.as_ptr(), 1)).map(|_| ())
     }
 }
 
@@ -480,10 +473,8 @@ pub fn unsetenv(n: &OsStr) -> io::Result<()> {
     let nbuf = CString::new(n.as_bytes())?;
 
     unsafe {
-        ENV_LOCK.lock();
-        let ret = cvt(libc::unsetenv(nbuf.as_ptr())).map(|_| ());
-        ENV_LOCK.unlock();
-        return ret
+        let _guard = ENV_LOCK.lock();
+        cvt(libc::unsetenv(nbuf.as_ptr())).map(|_| ())
     }
 }
 
@@ -572,7 +563,7 @@ fn glibc_version_cstr() -> Option<&'static CStr> {
 // ignoring any extra dot-separated parts. Otherwise return None.
 #[cfg(target_env = "gnu")]
 fn parse_glibc_version(version: &str) -> Option<(usize, usize)> {
-    let mut parsed_ints = version.split(".").map(str::parse::<usize>).fuse();
+    let mut parsed_ints = version.split('.').map(str::parse::<usize>).fuse();
     match (parsed_ints.next(), parsed_ints.next()) {
         (Some(Ok(major)), Some(Ok(minor))) => Some((major, minor)),
         _ => None
diff --git a/ctr-std/src/sys/unix/process/process_common.rs b/ctr-std/src/sys/unix/process/process_common.rs
index 6396bb3..77f125f 100644
--- a/ctr-std/src/sys/unix/process/process_common.rs
+++ b/ctr-std/src/sys/unix/process/process_common.rs
@@ -52,7 +52,7 @@ pub struct Command {
     uid: Option<uid_t>,
     gid: Option<gid_t>,
     saw_nul: bool,
-    closures: Vec<Box<FnMut() -> io::Result<()> + Send + Sync>>,
+    closures: Vec<Box<dyn FnMut() -> io::Result<()> + Send + Sync>>,
     stdin: Option<Stdio>,
     stdout: Option<Stdio>,
     stderr: Option<Stdio>,
@@ -155,12 +155,12 @@ impl Command {
         self.gid
     }
 
-    pub fn get_closures(&mut self) -> &mut Vec<Box<FnMut() -> io::Result<()> + Send + Sync>> {
+    pub fn get_closures(&mut self) -> &mut Vec<Box<dyn FnMut() -> io::Result<()> + Send + Sync>> {
         &mut self.closures
     }
 
     pub fn before_exec(&mut self,
-                       f: Box<FnMut() -> io::Result<()> + Send + Sync>) {
+                       f: Box<dyn FnMut() -> io::Result<()> + Send + Sync>) {
         self.closures.push(f);
     }
 
diff --git a/ctr-std/src/sys/unix/rand.rs b/ctr-std/src/sys/unix/rand.rs
index caa1894..01c0ada 100644
--- a/ctr-std/src/sys/unix/rand.rs
+++ b/ctr-std/src/sys/unix/rand.rs
@@ -183,35 +183,10 @@ mod imp {
 mod imp {
     #[link(name = "zircon")]
     extern {
-        fn zx_cprng_draw(buffer: *mut u8, len: usize, actual: *mut usize) -> i32;
-    }
-
-    fn getrandom(buf: &mut [u8]) -> Result<usize, i32> {
-        unsafe {
-            let mut actual = 0;
-            let status = zx_cprng_draw(buf.as_mut_ptr(), buf.len(), &mut actual);
-            if status == 0 {
-                Ok(actual)
-            } else {
-                Err(status)
-            }
-        }
+        fn zx_cprng_draw(buffer: *mut u8, len: usize);
     }
 
     pub fn fill_bytes(v: &mut [u8]) {
-        let mut buf = v;
-        while !buf.is_empty() {
-            let ret = getrandom(buf);
-            match ret {
-                Err(err) => {
-                    panic!("kernel zx_cprng_draw call failed! (returned {}, buf.len() {})",
-                        err, buf.len())
-                }
-                Ok(actual) => {
-                    let move_buf = buf;
-                    buf = &mut move_buf[(actual as usize)..];
-                }
-            }
-        }
+        unsafe { zx_cprng_draw(v.as_mut_ptr(), v.len()) }
     }
 }
diff --git a/ctr-std/src/sys/unix/thread.rs b/ctr-std/src/sys/unix/thread.rs
index 7fdecc9..f3a45d2 100644
--- a/ctr-std/src/sys/unix/thread.rs
+++ b/ctr-std/src/sys/unix/thread.rs
@@ -49,7 +49,7 @@ unsafe fn pthread_attr_setstacksize(_attr: *mut libc::pthread_attr_t,
 }
 
 impl Thread {
-    pub unsafe fn new<'a>(stack: usize, p: Box<FnBox() + 'a>)
+    pub unsafe fn new<'a>(stack: usize, p: Box<dyn FnBox() + 'a>)
                           -> io::Result<Thread> {
         let p = box p;
         let mut native: libc::pthread_t = mem::zeroed();
@@ -138,7 +138,8 @@ impl Thread {
               target_os = "solaris",
               target_os = "haiku",
               target_os = "l4re",
-              target_os = "emscripten"))]
+              target_os = "emscripten",
+              target_os = "hermit"))]
     pub fn set_name(_name: &CStr) {
         // Newlib, Illumos, Haiku, and Emscripten have no way to set a thread name.
     }
diff --git a/ctr-std/src/sys/unix/time.rs b/ctr-std/src/sys/unix/time.rs
index 89786eb..0b1fb72 100644
--- a/ctr-std/src/sys/unix/time.rs
+++ b/ctr-std/src/sys/unix/time.rs
@@ -345,9 +345,9 @@ mod inner {
         }
     }
 
-    #[cfg(not(target_os = "dragonfly"))]
+    #[cfg(not(any(target_os = "dragonfly", target_os = "hermit")))]
     pub type clock_t = libc::c_int;
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "dragonfly", target_os = "hermit"))]
     pub type clock_t = libc::c_ulong;
 
     fn now(clock: clock_t) -> Timespec {