diff --git a/ci/docker/wasm32-unknown-wasi/Dockerfile b/ci/docker/wasm32-unknown-wasi/Dockerfile
new file mode 100644
index 0000000000000000000000000000000000000000..b09cacb6c479f46ea4faa817f6de03ed260accfa
--- /dev/null
+++ b/ci/docker/wasm32-unknown-wasi/Dockerfile
@@ -0,0 +1,92 @@
+# In the first container we want to assemble the `wasi-sysroot` by compiling it
+# from source. This requires a clang 8.0+ compiler with enough wasm support and
+# then we're just running a standard `make` inside of what we clone.
+FROM ubuntu:18.04 as wasi-sysroot
+
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+    ca-certificates \
+    clang \
+    cmake \
+    curl \
+    g++ \
+    git \
+    libc6-dev \
+    libclang-dev \
+    make \
+    ssh \
+    xz-utils
+
+# Fetch clang 8.0+ which is used to compile the wasi target and link our
+# programs together.
+RUN curl http://releases.llvm.org/8.0.0/clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz | tar xJf -
+RUN mv /clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04 /wasmcc
+
+# Note that we're using `git reset --hard` to pin to a specific commit for
+# verification for now. The sysroot is currently in somewhat of a state of flux
+# and is expected to have breaking changes, so this is an attempt to mitigate
+# those breaking changes on `libc`'s own CI
+RUN git clone https://github.com/CraneStation/wasi-sysroot && \
+  cd wasi-sysroot && \
+  git reset --hard 320054e84f8f2440def3b1c8700cedb8fd697bf8
+RUN make -C wasi-sysroot install -j $(nproc) WASM_CC=/wasmcc/bin/clang INSTALL_DIR=/wasi-sysroot
+
+# This is a small wrapper script which executes the actual clang binary in
+# `/wasmcc` and then is sure to pass the right `--sysroot` argument which we
+# just built above.
+COPY docker/wasm32-unknown-wasi/clang.sh /wasi-sysroot/bin/clang
+
+# In the second container we're going to build the `wasmtime` binary which is
+# used to execute wasi executables. This is a standard Rust project so we're
+# just checking out a known revision (which pairs with the sysroot one we
+# downlaoded above) and then we're building it with Cargo
+FROM ubuntu:18.04 as wasmtime
+
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+    ca-certificates \
+    clang \
+    cmake \
+    curl \
+    g++ \
+    git \
+    libclang-dev \
+    make \
+    ssh
+
+RUN curl -sSf https://sh.rustup.rs |  sh -s -- -y
+ENV PATH=/root/.cargo/bin:$PATH
+
+RUN apt-get install -y --no-install-recommends python
+RUN git clone https://github.com/CraneStation/wasmtime-wasi wasmtime && \
+  cd wasmtime && \
+  git reset --hard 4fe2d6084e5b5cc74e69a26860f12750df51d339
+RUN cargo build --release --manifest-path wasmtime/Cargo.toml
+
+# And finally in the last image we're going to assemble everything together.
+# We'll install things needed at runtime for now and then copy over the
+# sysroot/wasmtime artifacts into their final location.
+FROM ubuntu:18.04
+
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+    gcc \
+    libc6-dev \
+    libxml2
+
+# Copy over clang we downloaded to link executables ...
+COPY --from=reference-sysroot /wasmcc /wasmcc/
+# ... and the sysroot we built to link executables against ...
+COPY --from=reference-sysroot /wasi-sysroot/ /wasi-sysroot/
+# ... and finally wasmtime to actually execute binaries
+COPY --from=wasmtime /wasmtime/target/release/wasmtime /usr/bin/
+
+# Of note here is our clang wrapper which just executes a normal clang
+# executable with the right sysroot, and then we're sure to turn off the
+# crt-static feature to ensure that the CRT that we're specifying with `clang`
+# is used.
+ENV CARGO_TARGET_WASM32_UNKNOWN_WASI_RUNNER=wasmtime \
+  CARGO_TARGET_WASM32_UNKNOWN_WASI_LINKER=/wasi-sysroot/bin/clang \
+  CC_wasm32_unknown_wasi=/wasi-sysroot/bin/clang \
+  PATH=$PATH:/rust/bin \
+  RUSTFLAGS=-Ctarget-feature=-crt-static
diff --git a/ci/docker/wasm32-unknown-wasi/clang.sh b/ci/docker/wasm32-unknown-wasi/clang.sh
new file mode 100755
index 0000000000000000000000000000000000000000..a943e3782334eb1fdb0dd3e5b5f281754326cf41
--- /dev/null
+++ b/ci/docker/wasm32-unknown-wasi/clang.sh
@@ -0,0 +1,2 @@
+#!/usr/bin/env sh
+exec /wasmcc/bin/clang --target=wasm32-unknown-wasi --sysroot /wasi-sysroot "$@"
diff --git a/ci/style.rs b/ci/style.rs
index 747e26c0a091f83b22c92ffb90964f82ca150c7d..481f57f74d0bcae34c88b7ef9116280cd0b84d35 100644
--- a/ci/style.rs
+++ b/ci/style.rs
@@ -144,6 +144,9 @@ fn check_style(file: &str, path: &Path, err: &mut Errors) {
         let line = if is_pub {&line[4..]} else {line};
 
         let line_state = if line.starts_with("use ") {
+            if line.contains("c_void") {
+                continue;
+            }
             if is_pub {
                 State::Modules
             } else {
diff --git a/libc-test/build.rs b/libc-test/build.rs
index 9ecfdc0d59516d50b460ece04a697e4ec58e0d57..3d8ddce44c0323492641e50680973f45a0f981eb 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -5,12 +5,12 @@ extern crate ctest;
 
 use std::env;
 
-#[cfg(unix)]
 fn do_cc() {
-    cc::Build::new().file("src/cmsg.c").compile("cmsg");
+    let target = env::var("TARGET").unwrap();
+    if cfg!(unix) && !target.contains("wasi") {
+        cc::Build::new().file("src/cmsg.c").compile("cmsg");
+    }
 }
-#[cfg(not(unix))]
-fn do_cc() {}
 
 fn do_ctest() {
     let target = env::var("TARGET").unwrap();
@@ -38,6 +38,7 @@ fn do_ctest() {
         t if t.contains("solaris") => return test_solaris(t),
         t if t.contains("netbsd") => return test_netbsd(t),
         t if t.contains("dragonfly") => return test_dragonflybsd(t),
+        t if t.contains("wasi") => return test_wasi(t),
         _ => (),
     }
 
@@ -1866,3 +1867,57 @@ fn test_dragonflybsd(target: &str) {
 
     cfg.generate("../src/lib.rs", "main.rs");
 }
+
+fn test_wasi(target: &str) {
+    assert!(target.contains("wasi"));
+
+    let mut cfg = ctest::TestGenerator::new();
+    cfg.define("_GNU_SOURCE", None);
+
+    headers! { cfg:
+        "errno.h",
+        "fcntl.h",
+        "limits.h",
+        "locale.h",
+        "malloc.h",
+        "stddef.h",
+        "stdint.h",
+        "stdio.h",
+        "stdlib.h",
+        "sys/stat.h",
+        "sys/types.h",
+        "time.h",
+        "unistd.h",
+        "wasi/core.h",
+        "wasi/libc.h",
+        "wchar.h",
+    }
+
+    cfg.type_name(move |ty, is_struct, is_union| match ty {
+        "FILE" => ty.to_string(),
+        t if is_union => format!("union {}", t),
+        t if t.starts_with("__wasi") && t.ends_with("_u") => {
+            format!("union {}", t)
+        }
+        t if t.starts_with("__wasi") && is_struct => format!("struct {}", t),
+        t if t.ends_with("_t") => t.to_string(),
+        t if is_struct => format!("struct {}", t),
+        t => t.to_string(),
+    });
+
+    cfg.field_name(move |_struct, field| {
+        match field {
+            // deal with fields as rust keywords
+            "type_" => "type".to_string(),
+            s => s.to_string(),
+        }
+    });
+
+    // Looks like LLD doesn't merge duplicate imports, so if the Rust
+    // code imports from a module and the C code also imports from a
+    // module we end up with two imports of function pointers which
+    // import the same thing but have different function pointers
+    cfg.skip_fn_ptrcheck(|f| f.starts_with("__wasi"));
+
+    cfg.generate("../src/lib.rs", "main.rs");
+}
diff --git a/src/lib.rs b/src/lib.rs
index 2c30576bade305677582c6d2d4b7763a55c61155..2571f81a6cfbd99b5583d452a4e6149627702a8f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -112,7 +112,10 @@ cfg_if! {
     } else if #[cfg(all(target_env = "sgx", target_vendor = "fortanix"))] {
         mod sgx;
         pub use sgx::*;
-    }  else {
+    } else if #[cfg(target_env = "wasi")] {
+        mod wasi;
+        pub use wasi::*;
+    } else {
         // non-supported targets: empty...
     }
 }
diff --git a/src/wasi.rs b/src/wasi.rs
new file mode 100644
index 0000000000000000000000000000000000000000..13af0b53682dfaf196bdd6074081ef2814073b3d
--- /dev/null
+++ b/src/wasi.rs
@@ -0,0 +1,778 @@
+pub use ffi::c_void;
+
+pub type c_char = i8;
+pub type c_uchar = u8;
+pub type c_int = i32;
+pub type c_uint = u32;
+pub type c_short = i16;
+pub type c_ushort = u16;
+pub type c_long = i32;
+pub type c_ulong = u32;
+pub type c_longlong = i64;
+pub type c_ulonglong = u64;
+pub type size_t = usize;
+pub type ssize_t = isize;
+pub type off_t = i64;
+pub type pid_t = i32;
+pub type int8_t = i8;
+pub type uint8_t = u8;
+pub type int16_t = i16;
+pub type uint16_t = u16;
+pub type int32_t = i32;
+pub type uint32_t = u32;
+pub type int64_t = i64;
+pub type uint64_t = u64;
+pub type clock_t = c_longlong;
+pub type time_t = c_longlong;
+pub type c_double = f64;
+pub type c_float = f32;
+
+pub type __wasi_advice_t = u8;
+pub type __wasi_clockid_t = u32;
+pub type __wasi_device_t = u64;
+pub type __wasi_dircookie_t = u64;
+pub type __wasi_errno_t = u16;
+pub type __wasi_eventrwflags_t = u16;
+pub type __wasi_eventtype_t = u8;
+pub type __wasi_exitcode_t = u32;
+pub type __wasi_fd_t = u32;
+pub type __wasi_fdflags_t = u16;
+pub type __wasi_filedelta_t = i64;
+pub type __wasi_filesize_t = u64;
+pub type __wasi_filetype_t = u8;
+pub type __wasi_fstflags_t = u16;
+pub type __wasi_inode_t = u64;
+pub type __wasi_linkcount_t = u32;
+pub type __wasi_lookupflags_t = u32;
+pub type __wasi_oflags_t = u16;
+pub type __wasi_riflags_t = u16;
+pub type __wasi_rights_t = u64;
+pub type __wasi_roflags_t = u16;
+pub type __wasi_sdflags_t = u8;
+pub type __wasi_siflags_t = u16;
+pub type __wasi_signal_t = u8;
+pub type __wasi_subclockflags_t = u16;
+pub type __wasi_timestamp_t = u64;
+pub type __wasi_userdata_t = u64;
+pub type __wasi_whence_t = u8;
+pub type __wasi_preopentype_t = u8;
+
+#[cfg_attr(feature = "extra_traits", derive(Debug))]
+pub enum FILE {}
+impl ::Copy for FILE {}
+impl ::Clone for FILE {
+    fn clone(&self) -> FILE {
+        *self
+    }
+}
+
+s! {
+    #[repr(align(8))]
+    pub struct fpos_t {
+        data: [u8; 16],
+    }
+
+    pub struct tm {
+        pub tm_sec: c_int,
+        pub tm_min: c_int,
+        pub tm_hour: c_int,
+        pub tm_mday: c_int,
+        pub tm_mon: c_int,
+        pub tm_year: c_int,
+        pub tm_wday: c_int,
+        pub tm_yday: c_int,
+        pub tm_isdst: c_int,
+        pub __tm_gmtoff: c_int,
+        pub __tm_zone: *const c_char,
+        pub __tm_nsec: c_int,
+    }
+
+    pub struct timespec {
+        pub tv_sec: time_t,
+        pub tv_nsec: c_long,
+    }
+
+    pub struct itimerspec {
+        pub it_interval: timespec,
+        pub it_value: timespec,
+    }
+
+    pub struct __wasi_dirent_t {
+        pub d_next: __wasi_dircookie_t,
+        pub d_ino: __wasi_inode_t,
+        pub d_namlen: u32,
+        pub d_type: __wasi_filetype_t,
+    }
+
+    pub struct __wasi_event_u_fd_readwrite_t {
+        pub nbytes: __wasi_filesize_t,
+        pub flags: __wasi_eventrwflags_t,
+    }
+
+    pub struct __wasi_fdstat_t {
+        pub fs_filetype: __wasi_filetype_t,
+        pub fs_flags: __wasi_fdflags_t,
+        pub fs_rights_base: __wasi_rights_t,
+        pub fs_rights_inheriting: __wasi_rights_t,
+    }
+
+    pub struct __wasi_filestat_t {
+        pub st_dev: __wasi_device_t,
+        pub st_ino: __wasi_inode_t,
+        pub st_filetype: __wasi_filetype_t,
+        pub st_nlink: __wasi_linkcount_t,
+        pub st_size: __wasi_filesize_t,
+        pub st_atim: __wasi_timestamp_t,
+        pub st_mtim: __wasi_timestamp_t,
+        pub st_ctim: __wasi_timestamp_t,
+    }
+
+    pub struct __wasi_ciovec_t {
+        pub buf: *const ::c_void,
+        pub buf_len: size_t,
+    }
+
+    pub struct __wasi_iovec_t {
+        pub buf: *mut ::c_void,
+        pub buf_len: size_t,
+    }
+
+    pub struct __wasi_subscription_u_clock_t {
+        pub identifier: __wasi_userdata_t,
+        pub clock_id: __wasi_clockid_t,
+        pub timeout: __wasi_timestamp_t,
+        pub precision: __wasi_timestamp_t,
+        pub flags: __wasi_subclockflags_t,
+    }
+
+    pub struct __wasi_subscription_u_fd_readwrite_t {
+        pub fd: __wasi_fd_t,
+    }
+
+    pub struct __wasi_prestat_u_dir_t {
+        pub pr_name_len: size_t,
+    }
+}
+
+s_no_extra_traits! {
+    #[allow(missing_debug_implementations)]
+    pub struct __wasi_subscription_t {
+        pub userdata: __wasi_userdata_t,
+        pub type_: __wasi_eventtype_t,
+        pub u: __wasi_subscription_u,
+    }
+
+    #[allow(missing_debug_implementations)]
+    pub struct __wasi_event_t {
+        pub userdata: __wasi_userdata_t,
+        pub error: __wasi_errno_t,
+        pub type_: __wasi_eventtype_t,
+        pub u: __wasi_event_u,
+    }
+
+    #[allow(missing_debug_implementations)]
+    pub union __wasi_event_u {
+        pub fd_readwrite: __wasi_event_u_fd_readwrite_t,
+        _bindgen_union_align: [u64; 2],
+    }
+
+    #[allow(missing_debug_implementations)]
+    pub union __wasi_subscription_u {
+        pub clock: __wasi_subscription_u_clock_t,
+        pub fd_readwrite:
+            __wasi_subscription_u_fd_readwrite_t,
+        _bindgen_union_align: [u64; 5],
+    }
+
+    #[allow(missing_debug_implementations)]
+    pub struct __wasi_prestat_t {
+        pub pr_type: __wasi_preopentype_t,
+        pub u: __wasi_prestat_u,
+    }
+
+    #[allow(missing_debug_implementations)]
+    pub union __wasi_prestat_u {
+        pub dir: __wasi_prestat_u_dir_t,
+    }
+
+}
+
+pub const STDIN_FILENO: c_int = 0;
+pub const STDOUT_FILENO: c_int = 1;
+pub const STDERR_FILENO: c_int = 2;
+pub const SEEK_SET: c_int = 2;
+pub const SEEK_CUR: c_int = 0;
+pub const SEEK_END: c_int = 1;
+
+pub const __WASI_ADVICE_NORMAL: u8 = 0;
+pub const __WASI_ADVICE_SEQUENTIAL: u8 = 1;
+pub const __WASI_ADVICE_RANDOM: u8 = 2;
+pub const __WASI_ADVICE_WILLNEED: u8 = 3;
+pub const __WASI_ADVICE_DONTNEED: u8 = 4;
+pub const __WASI_ADVICE_NOREUSE: u8 = 5;
+pub const __WASI_CLOCK_REALTIME: u32 = 0;
+pub const __WASI_CLOCK_MONOTONIC: u32 = 1;
+pub const __WASI_CLOCK_PROCESS_CPUTIME_ID: u32 = 2;
+pub const __WASI_CLOCK_THREAD_CPUTIME_ID: u32 = 3;
+pub const __WASI_DIRCOOKIE_START: u64 = 0;
+pub const __WASI_ESUCCESS: u16 = 0;
+pub const __WASI_E2BIG: u16 = 1;
+pub const __WASI_EACCES: u16 = 2;
+pub const __WASI_EADDRINUSE: u16 = 3;
+pub const __WASI_EADDRNOTAVAIL: u16 = 4;
+pub const __WASI_EAFNOSUPPORT: u16 = 5;
+pub const __WASI_EAGAIN: u16 = 6;
+pub const __WASI_EALREADY: u16 = 7;
+pub const __WASI_EBADF: u16 = 8;
+pub const __WASI_EBADMSG: u16 = 9;
+pub const __WASI_EBUSY: u16 = 10;
+pub const __WASI_ECANCELED: u16 = 11;
+pub const __WASI_ECHILD: u16 = 12;
+pub const __WASI_ECONNABORTED: u16 = 13;
+pub const __WASI_ECONNREFUSED: u16 = 14;
+pub const __WASI_ECONNRESET: u16 = 15;
+pub const __WASI_EDEADLK: u16 = 16;
+pub const __WASI_EDESTADDRREQ: u16 = 17;
+pub const __WASI_EDOM: u16 = 18;
+pub const __WASI_EDQUOT: u16 = 19;
+pub const __WASI_EEXIST: u16 = 20;
+pub const __WASI_EFAULT: u16 = 21;
+pub const __WASI_EFBIG: u16 = 22;
+pub const __WASI_EHOSTUNREACH: u16 = 23;
+pub const __WASI_EIDRM: u16 = 24;
+pub const __WASI_EILSEQ: u16 = 25;
+pub const __WASI_EINPROGRESS: u16 = 26;
+pub const __WASI_EINTR: u16 = 27;
+pub const __WASI_EINVAL: u16 = 28;
+pub const __WASI_EIO: u16 = 29;
+pub const __WASI_EISCONN: u16 = 30;
+pub const __WASI_EISDIR: u16 = 31;
+pub const __WASI_ELOOP: u16 = 32;
+pub const __WASI_EMFILE: u16 = 33;
+pub const __WASI_EMLINK: u16 = 34;
+pub const __WASI_EMSGSIZE: u16 = 35;
+pub const __WASI_EMULTIHOP: u16 = 36;
+pub const __WASI_ENAMETOOLONG: u16 = 37;
+pub const __WASI_ENETDOWN: u16 = 38;
+pub const __WASI_ENETRESET: u16 = 39;
+pub const __WASI_ENETUNREACH: u16 = 40;
+pub const __WASI_ENFILE: u16 = 41;
+pub const __WASI_ENOBUFS: u16 = 42;
+pub const __WASI_ENODEV: u16 = 43;
+pub const __WASI_ENOENT: u16 = 44;
+pub const __WASI_ENOEXEC: u16 = 45;
+pub const __WASI_ENOLCK: u16 = 46;
+pub const __WASI_ENOLINK: u16 = 47;
+pub const __WASI_ENOMEM: u16 = 48;
+pub const __WASI_ENOMSG: u16 = 49;
+pub const __WASI_ENOPROTOOPT: u16 = 50;
+pub const __WASI_ENOSPC: u16 = 51;
+pub const __WASI_ENOSYS: u16 = 52;
+pub const __WASI_ENOTCONN: u16 = 53;
+pub const __WASI_ENOTDIR: u16 = 54;
+pub const __WASI_ENOTEMPTY: u16 = 55;
+pub const __WASI_ENOTRECOVERABLE: u16 = 56;
+pub const __WASI_ENOTSOCK: u16 = 57;
+pub const __WASI_ENOTSUP: u16 = 58;
+pub const __WASI_ENOTTY: u16 = 59;
+pub const __WASI_ENXIO: u16 = 60;
+pub const __WASI_EOVERFLOW: u16 = 61;
+pub const __WASI_EOWNERDEAD: u16 = 62;
+pub const __WASI_EPERM: u16 = 63;
+pub const __WASI_EPIPE: u16 = 64;
+pub const __WASI_EPROTO: u16 = 65;
+pub const __WASI_EPROTONOSUPPORT: u16 = 66;
+pub const __WASI_EPROTOTYPE: u16 = 67;
+pub const __WASI_ERANGE: u16 = 68;
+pub const __WASI_EROFS: u16 = 69;
+pub const __WASI_ESPIPE: u16 = 70;
+pub const __WASI_ESRCH: u16 = 71;
+pub const __WASI_ESTALE: u16 = 72;
+pub const __WASI_ETIMEDOUT: u16 = 73;
+pub const __WASI_ETXTBSY: u16 = 74;
+pub const __WASI_EXDEV: u16 = 75;
+pub const __WASI_ENOTCAPABLE: u16 = 76;
+pub const __WASI_EVENT_FD_READWRITE_HANGUP: u16 = 0x0001;
+pub const __WASI_EVENTTYPE_CLOCK: u8 = 0;
+pub const __WASI_EVENTTYPE_FD_READ: u8 = 1;
+pub const __WASI_EVENTTYPE_FD_WRITE: u8 = 2;
+pub const __WASI_FDFLAG_APPEND: u16 = 0x0001;
+pub const __WASI_FDFLAG_DSYNC: u16 = 0x0002;
+pub const __WASI_FDFLAG_NONBLOCK: u16 = 0x0004;
+pub const __WASI_FDFLAG_RSYNC: u16 = 0x0008;
+pub const __WASI_FDFLAG_SYNC: u16 = 0x0010;
+pub const __WASI_FILETYPE_UNKNOWN: u8 = 0;
+pub const __WASI_FILETYPE_BLOCK_DEVICE: u8 = 1;
+pub const __WASI_FILETYPE_CHARACTER_DEVICE: u8 = 2;
+pub const __WASI_FILETYPE_DIRECTORY: u8 = 3;
+pub const __WASI_FILETYPE_REGULAR_FILE: u8 = 4;
+pub const __WASI_FILETYPE_SOCKET_DGRAM: u8 = 5;
+pub const __WASI_FILETYPE_SOCKET_STREAM: u8 = 6;
+pub const __WASI_FILETYPE_SYMBOLIC_LINK: u8 = 7;
+pub const __WASI_FILESTAT_SET_ATIM: u16 = 0x0001;
+pub const __WASI_FILESTAT_SET_ATIM_NOW: u16 = 0x0002;
+pub const __WASI_FILESTAT_SET_MTIM: u16 = 0x0004;
+pub const __WASI_FILESTAT_SET_MTIM_NOW: u16 = 0x0008;
+pub const __WASI_LOOKUP_SYMLINK_FOLLOW: u32 = 0x00000001;
+pub const __WASI_O_CREAT: u16 = 0x0001;
+pub const __WASI_O_DIRECTORY: u16 = 0x0002;
+pub const __WASI_O_EXCL: u16 = 0x0004;
+pub const __WASI_O_TRUNC: u16 = 0x0008;
+pub const __WASI_PREOPENTYPE_DIR: u8 = 0;
+pub const __WASI_SOCK_RECV_PEEK: u16 = 0x0001;
+pub const __WASI_SOCK_RECV_WAITALL: u16 = 0x0002;
+pub const __WASI_RIGHT_FD_DATASYNC: u64 = 0x0000000000000001;
+pub const __WASI_RIGHT_FD_READ: u64 = 0x0000000000000002;
+pub const __WASI_RIGHT_FD_SEEK: u64 = 0x0000000000000004;
+pub const __WASI_RIGHT_FD_FDSTAT_SET_FLAGS: u64 = 0x0000000000000008;
+pub const __WASI_RIGHT_FD_SYNC: u64 = 0x0000000000000010;
+pub const __WASI_RIGHT_FD_TELL: u64 = 0x0000000000000020;
+pub const __WASI_RIGHT_FD_WRITE: u64 = 0x0000000000000040;
+pub const __WASI_RIGHT_FD_ADVISE: u64 = 0x0000000000000080;
+pub const __WASI_RIGHT_FD_ALLOCATE: u64 = 0x0000000000000100;
+pub const __WASI_RIGHT_PATH_CREATE_DIRECTORY: u64 = 0x0000000000000200;
+pub const __WASI_RIGHT_PATH_CREATE_FILE: u64 = 0x0000000000000400;
+pub const __WASI_RIGHT_PATH_LINK_SOURCE: u64 = 0x0000000000000800;
+pub const __WASI_RIGHT_PATH_LINK_TARGET: u64 = 0x0000000000001000;
+pub const __WASI_RIGHT_PATH_OPEN: u64 = 0x0000000000002000;
+pub const __WASI_RIGHT_FD_READDIR: u64 = 0x0000000000004000;
+pub const __WASI_RIGHT_PATH_READLINK: u64 = 0x0000000000008000;
+pub const __WASI_RIGHT_PATH_RENAME_SOURCE: u64 = 0x0000000000010000;
+pub const __WASI_RIGHT_PATH_RENAME_TARGET: u64 = 0x0000000000020000;
+pub const __WASI_RIGHT_PATH_FILESTAT_GET: u64 = 0x0000000000040000;
+pub const __WASI_RIGHT_PATH_FILESTAT_SET_SIZE: u64 = 0x0000000000080000;
+pub const __WASI_RIGHT_PATH_FILESTAT_SET_TIMES: u64 = 0x0000000000100000;
+pub const __WASI_RIGHT_FD_FILESTAT_GET: u64 = 0x0000000000200000;
+pub const __WASI_RIGHT_FD_FILESTAT_SET_SIZE: u64 = 0x0000000000400000;
+pub const __WASI_RIGHT_FD_FILESTAT_SET_TIMES: u64 = 0x0000000000800000;
+pub const __WASI_RIGHT_PATH_SYMLINK: u64 = 0x0000000001000000;
+pub const __WASI_RIGHT_PATH_REMOVE_DIRECTORY: u64 = 0x0000000002000000;
+pub const __WASI_RIGHT_PATH_UNLINK_FILE: u64 = 0x0000000004000000;
+pub const __WASI_RIGHT_POLL_FD_READWRITE: u64 = 0x0000000008000000;
+pub const __WASI_RIGHT_SOCK_SHUTDOWN: u64 = 0x0000000010000000;
+pub const __WASI_SOCK_RECV_DATA_TRUNCATED: u16 = 0x0001;
+pub const __WASI_SHUT_RD: u8 = 0x01;
+pub const __WASI_SHUT_WR: u8 = 0x02;
+pub const __WASI_SIGHUP: u8 = 1;
+pub const __WASI_SIGINT: u8 = 2;
+pub const __WASI_SIGQUIT: u8 = 3;
+pub const __WASI_SIGILL: u8 = 4;
+pub const __WASI_SIGTRAP: u8 = 5;
+pub const __WASI_SIGABRT: u8 = 6;
+pub const __WASI_SIGBUS: u8 = 7;
+pub const __WASI_SIGFPE: u8 = 8;
+pub const __WASI_SIGKILL: u8 = 9;
+pub const __WASI_SIGUSR1: u8 = 10;
+pub const __WASI_SIGSEGV: u8 = 11;
+pub const __WASI_SIGUSR2: u8 = 12;
+pub const __WASI_SIGPIPE: u8 = 13;
+pub const __WASI_SIGALRM: u8 = 14;
+pub const __WASI_SIGTERM: u8 = 15;
+pub const __WASI_SIGCHLD: u8 = 16;
+pub const __WASI_SIGCONT: u8 = 17;
+pub const __WASI_SIGSTOP: u8 = 18;
+pub const __WASI_SIGTSTP: u8 = 19;
+pub const __WASI_SIGTTIN: u8 = 20;
+pub const __WASI_SIGTTOU: u8 = 21;
+pub const __WASI_SIGURG: u8 = 22;
+pub const __WASI_SIGXCPU: u8 = 23;
+pub const __WASI_SIGXFSZ: u8 = 24;
+pub const __WASI_SIGVTALRM: u8 = 25;
+pub const __WASI_SIGPROF: u8 = 26;
+pub const __WASI_SIGWINCH: u8 = 27;
+pub const __WASI_SIGPOLL: u8 = 28;
+pub const __WASI_SIGPWR: u8 = 29;
+pub const __WASI_SIGSYS: u8 = 30;
+pub const __WASI_SUBSCRIPTION_CLOCK_ABSTIME: u16 = 0x0001;
+pub const __WASI_WHENCE_CUR: u8 = 0;
+pub const __WASI_WHENCE_END: u8 = 1;
+pub const __WASI_WHENCE_SET: u8 = 2;
+
+#[cfg_attr(feature = "rustc-dep-of-std",
+           link(name = "c", kind = "static",
+                cfg(target_feature = "crt-static")))]
+#[cfg_attr(feature = "rustc-dep-of-std",
+           link(name = "c", cfg(not(target_feature = "crt-static"))))]
+extern {
+    pub fn _Exit(code: c_int) -> !;
+    pub fn _exit(code: c_int) -> !;
+    pub fn abort() -> !;
+    pub fn aligned_alloc(a: size_t, b: size_t) -> *mut c_void;
+    pub fn calloc(amt: size_t, amt2: size_t) -> *mut c_void;
+    pub fn exit(code: c_int) -> !;
+    pub fn free(ptr: *mut c_void);
+    pub fn getenv(s: *const c_char) -> *mut c_char;
+    pub fn malloc(amt: size_t) -> *mut c_void;
+    pub fn malloc_usable_size(ptr: *mut c_void) -> size_t;
+    pub fn rand() -> c_int;
+    pub fn read(fd: c_int, ptr: *mut c_void, size: size_t) -> ssize_t;
+    pub fn realloc(ptr: *mut c_void, amt: size_t) -> *mut c_void;
+    pub fn setenv(k: *const c_char, v: *const c_char, a: c_int) -> c_int;
+    pub fn unsetenv(k: *const c_char) -> c_int;
+    pub fn write(fd: c_int, ptr: *const c_void, size: size_t) -> ssize_t;
+    pub static mut environ: *mut *mut c_char;
+    pub fn fopen(a: *const c_char, b: *const c_char) -> *mut FILE;
+    pub fn freopen(
+        a: *const c_char,
+        b: *const c_char,
+        f: *mut FILE,
+    ) -> *mut FILE;
+    pub fn fclose(f: *mut FILE) -> c_int;
+    pub fn remove(a: *const c_char) -> c_int;
+    pub fn rename(a: *const c_char, b: *const c_char) -> c_int;
+    pub fn feof(f: *mut FILE) -> c_int;
+    pub fn ferror(f: *mut FILE) -> c_int;
+    pub fn fflush(f: *mut FILE) -> c_int;
+    pub fn clearerr(f: *mut FILE);
+    pub fn fseek(f: *mut FILE, b: c_long, c: c_int) -> c_int;
+    pub fn ftell(f: *mut FILE) -> c_long;
+    pub fn rewind(f: *mut FILE);
+    pub fn fgetpos(f: *mut FILE, pos: *mut fpos_t) -> c_int;
+    pub fn fsetpos(f: *mut FILE, pos: *const fpos_t) -> c_int;
+    pub fn fread(
+        buf: *mut c_void,
+        a: size_t,
+        b: size_t,
+        f: *mut FILE,
+    ) -> size_t;
+    pub fn fwrite(
+        buf: *const c_void,
+        a: size_t,
+        b: size_t,
+        f: *mut FILE,
+    ) -> size_t;
+    pub fn fgetc(f: *mut FILE) -> c_int;
+    pub fn getc(f: *mut FILE) -> c_int;
+    pub fn getchar() -> c_int;
+    pub fn ungetc(a: c_int, f: *mut FILE) -> c_int;
+    pub fn fputc(a: c_int, f: *mut FILE) -> c_int;
+    pub fn putc(a: c_int, f: *mut FILE) -> c_int;
+    pub fn putchar(a: c_int) -> c_int;
+    pub fn fputs(a: *const c_char, f: *mut FILE) -> c_int;
+    pub fn puts(a: *const c_char) -> c_int;
+    pub fn perror(a: *const c_char);
+    pub fn srand(a: c_uint);
+    pub fn atexit(a: extern fn()) -> c_int;
+    pub fn at_quick_exit(a: extern fn()) -> c_int;
+    pub fn quick_exit(a: c_int) -> !;
+    pub fn posix_memalign(a: *mut *mut c_void, b: size_t, c: size_t) -> c_int;
+    pub fn rand_r(a: *mut c_uint) -> c_int;
+    pub fn random() -> c_long;
+    pub fn srandom(a: c_uint);
+    pub fn putenv(a: *mut c_char) -> c_int;
+    pub fn clock() -> clock_t;
+    pub fn time(a: *mut time_t) -> time_t;
+    pub fn difftime(a: time_t, b: time_t) -> c_double;
+    pub fn mktime(a: *mut tm) -> time_t;
+    pub fn strftime(
+        a: *mut c_char,
+        b: size_t,
+        c: *const c_char,
+        d: *const tm,
+    ) -> size_t;
+    pub fn gmtime(a: *const time_t) -> *mut tm;
+    pub fn gmtime_r(a: *const time_t, b: *mut tm) -> *mut tm;
+    pub fn localtime_r(a: *const time_t, b: *mut tm) -> *mut tm;
+    pub fn asctime_r(a: *const tm, b: *mut c_char) -> *mut c_char;
+    pub fn ctime_r(a: *const time_t, b: *mut c_char) -> *mut c_char;
+
+    pub fn nanosleep(a: *const timespec, b: *mut timespec) -> c_int;
+    // pub fn clock_getres(a: clockid_t, b: *mut timespec) -> c_int;
+    // pub fn clock_gettime(a: clockid_t, b: *mut timespec) -> c_int;
+    // pub fn clock_nanosleep(
+    //     a: clockid_t,
+    //     a2: c_int,
+    //     b: *const timespec,
+    //     c: *mut timespec,
+    // ) -> c_int;
+
+    pub fn __wasilibc_register_preopened_fd(
+        fd: c_int,
+        path: *const c_char,
+    ) -> c_int;
+    pub fn __wasilibc_fd_renumber(fd: c_int, newfd: c_int) -> c_int;
+    pub fn __wasilibc_rmfileat(fd: c_int, path: *const c_char) -> c_int;
+    pub fn __wasilibc_rmdirat(fd: c_int, path: *const c_char) -> c_int;
+    pub fn __wasilibc_init_preopen();
+
+    pub fn arc4random() -> u32;
+    pub fn arc4random_buf(a: *mut c_void, b: size_t);
+    pub fn arc4random_uniform(a: u32) -> u32;
+}
+
+#[link(wasm_import_module = "wasi_unstable")]
+extern {
+    #[link_name = "clock_res_get"]
+    pub fn __wasi_clock_res_get(
+        clock_id: __wasi_clockid_t,
+        resolution: *mut __wasi_timestamp_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "clock_time_get"]
+    pub fn __wasi_clock_time_get(
+        clock_id: __wasi_clockid_t,
+        precision: __wasi_timestamp_t,
+        time: *mut __wasi_timestamp_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_close"]
+    pub fn __wasi_fd_close(fd: __wasi_fd_t) -> __wasi_errno_t;
+    #[link_name = "fd_datasync"]
+    pub fn __wasi_fd_datasync(fd: __wasi_fd_t) -> __wasi_errno_t;
+    #[link_name = "fd_pread"]
+    pub fn __wasi_fd_pread(
+        fd: __wasi_fd_t,
+        iovs: *const __wasi_iovec_t,
+        iovs_len: size_t,
+        offset: __wasi_filesize_t,
+        nread: *mut size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_pwrite"]
+    pub fn __wasi_fd_pwrite(
+        fd: __wasi_fd_t,
+        iovs: *const __wasi_ciovec_t,
+        iovs_len: size_t,
+        offset: __wasi_filesize_t,
+        nwritten: *mut size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_read"]
+    pub fn __wasi_fd_read(
+        fd: __wasi_fd_t,
+        iovs: *const __wasi_iovec_t,
+        iovs_len: size_t,
+        nread: *mut size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_renumber"]
+    pub fn __wasi_fd_renumber(
+        from: __wasi_fd_t,
+        to: __wasi_fd_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_seek"]
+    pub fn __wasi_fd_seek(
+        fd: __wasi_fd_t,
+        offset: __wasi_filedelta_t,
+        whence: __wasi_whence_t,
+        newoffset: *mut __wasi_filesize_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_tell"]
+    pub fn __wasi_fd_tell(
+        fd: __wasi_fd_t,
+        newoffset: *mut __wasi_filesize_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_fdstat_get"]
+    pub fn __wasi_fd_fdstat_get(
+        fd: __wasi_fd_t,
+        buf: *mut __wasi_fdstat_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_fdstat_set_flags"]
+    pub fn __wasi_fd_fdstat_set_flags(
+        fd: __wasi_fd_t,
+        flags: __wasi_fdflags_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_fdstat_set_rights"]
+    pub fn __wasi_fd_fdstat_set_rights(
+        fd: __wasi_fd_t,
+        fs_rights_base: __wasi_rights_t,
+        fs_rights_inheriting: __wasi_rights_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_sync"]
+    pub fn __wasi_fd_sync(fd: __wasi_fd_t) -> __wasi_errno_t;
+    #[link_name = "fd_write"]
+    pub fn __wasi_fd_write(
+        fd: __wasi_fd_t,
+        iovs: *const __wasi_ciovec_t,
+        iovs_len: size_t,
+        nwritten: *mut size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_advise"]
+    pub fn __wasi_fd_advise(
+        fd: __wasi_fd_t,
+        offset: __wasi_filesize_t,
+        len: __wasi_filesize_t,
+        advice: __wasi_advice_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_allocate"]
+    pub fn __wasi_fd_allocate(
+        fd: __wasi_fd_t,
+        offset: __wasi_filesize_t,
+        len: __wasi_filesize_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "path_create_directory"]
+    pub fn __wasi_path_create_directory(
+        fd: __wasi_fd_t,
+        path: *const ::c_char,
+        path_len: size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "path_link"]
+    pub fn __wasi_path_link(
+        old_fd: __wasi_fd_t,
+        old_flags: __wasi_lookupflags_t,
+        old_path: *const ::c_char,
+        old_path_len: size_t,
+        new_fd: __wasi_fd_t,
+        new_path: *const ::c_char,
+        new_path_len: size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "path_open"]
+    pub fn __wasi_path_open(
+        dirfd: __wasi_fd_t,
+        dirflags: __wasi_lookupflags_t,
+        path: *const ::c_char,
+        path_len: size_t,
+        oflags: __wasi_oflags_t,
+        fs_rights_base: __wasi_rights_t,
+        fs_rights_inheriting: __wasi_rights_t,
+        fs_flags: __wasi_fdflags_t,
+        fd: *mut __wasi_fd_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_readdir"]
+    pub fn __wasi_fd_readdir(
+        fd: __wasi_fd_t,
+        buf: *mut ::c_void,
+        buf_len: size_t,
+        cookie: __wasi_dircookie_t,
+        bufused: *mut size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "path_readlink"]
+    pub fn __wasi_path_readlink(
+        fd: __wasi_fd_t,
+        path: *const ::c_char,
+        path_len: size_t,
+        buf: *mut ::c_char,
+        buf_len: size_t,
+        bufused: *mut size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "path_rename"]
+    pub fn __wasi_path_rename(
+        old_fd: __wasi_fd_t,
+        old_path: *const ::c_char,
+        old_path_len: size_t,
+        new_fd: __wasi_fd_t,
+        new_path: *const ::c_char,
+        new_path_len: size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_filestat_get"]
+    pub fn __wasi_fd_filestat_get(
+        fd: __wasi_fd_t,
+        buf: *mut __wasi_filestat_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_filestat_set_times"]
+    pub fn __wasi_fd_filestat_set_times(
+        fd: __wasi_fd_t,
+        st_atim: __wasi_timestamp_t,
+        st_mtim: __wasi_timestamp_t,
+        fstflags: __wasi_fstflags_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_filestat_set_size"]
+    pub fn __wasi_fd_filestat_set_size(
+        fd: __wasi_fd_t,
+        st_size: __wasi_filesize_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "path_filestat_get"]
+    pub fn __wasi_path_filestat_get(
+        fd: __wasi_fd_t,
+        flags: __wasi_lookupflags_t,
+        path: *const ::c_char,
+        path_len: size_t,
+        buf: *mut __wasi_filestat_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "path_filestat_set_times"]
+    pub fn __wasi_path_filestat_set_times(
+        fd: __wasi_fd_t,
+        flags: __wasi_lookupflags_t,
+        path: *const ::c_char,
+        path_len: size_t,
+        st_atim: __wasi_timestamp_t,
+        st_mtim: __wasi_timestamp_t,
+        fstflags: __wasi_fstflags_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "path_symlink"]
+    pub fn __wasi_path_symlink(
+        old_path: *const ::c_char,
+        old_path_len: size_t,
+        fd: __wasi_fd_t,
+        new_path: *const ::c_char,
+        new_path_len: size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "path_unlink_file"]
+    pub fn __wasi_path_unlink_file(
+        fd: __wasi_fd_t,
+        path: *const ::c_char,
+        path_len: size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "path_remove_directory"]
+    pub fn __wasi_path_remove_directory(
+        fd: __wasi_fd_t,
+        path: *const ::c_char,
+        path_len: size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "poll_oneoff"]
+    pub fn __wasi_poll_oneoff(
+        in_: *const __wasi_subscription_t,
+        out: *mut __wasi_event_t,
+        nsubscriptions: size_t,
+        nevents: *mut size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "proc_exit"]
+    pub fn __wasi_proc_exit(rval: __wasi_exitcode_t);
+    #[link_name = "proc_raise"]
+    pub fn __wasi_proc_raise(sig: __wasi_signal_t) -> __wasi_errno_t;
+    #[link_name = "random_get"]
+    pub fn __wasi_random_get(
+        buf: *mut ::c_void,
+        buf_len: size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "sock_recv"]
+    pub fn __wasi_sock_recv(
+        sock: __wasi_fd_t,
+        ri_data: *const __wasi_iovec_t,
+        ri_data_len: size_t,
+        ri_flags: __wasi_riflags_t,
+        ro_datalen: *mut size_t,
+        ro_flags: *mut __wasi_roflags_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "sock_send"]
+    pub fn __wasi_sock_send(
+        sock: __wasi_fd_t,
+        si_data: *const __wasi_ciovec_t,
+        si_data_len: size_t,
+        si_flags: __wasi_siflags_t,
+        so_datalen: *mut size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "sock_shutdown"]
+    pub fn __wasi_sock_shutdown(
+        sock: __wasi_fd_t,
+        how: __wasi_sdflags_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "sched_yield"]
+    pub fn __wasi_sched_yield() -> __wasi_errno_t;
+    #[link_name = "args_get"]
+    pub fn __wasi_args_get(
+        argv: *mut *mut c_char,
+        argv_buf: *mut c_char,
+    ) -> __wasi_errno_t;
+    #[link_name = "args_sizes_get"]
+    pub fn __wasi_args_sizes_get(
+        argc: *mut size_t,
+        argv_buf_size: *mut size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "environ_get"]
+    pub fn __wasi_environ_get(
+        environ: *mut *mut c_char,
+        environ_buf: *mut c_char,
+    ) -> __wasi_errno_t;
+    #[link_name = "environ_sizes_get"]
+    pub fn __wasi_environ_sizes_get(
+        environ_count: *mut size_t,
+        environ_buf_size: *mut size_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_prestat_get"]
+    pub fn __wasi_fd_prestat_get(
+        fd: __wasi_fd_t,
+        buf: *mut __wasi_prestat_t,
+    ) -> __wasi_errno_t;
+    #[link_name = "fd_prestat_dir_name"]
+    pub fn __wasi_fd_prestat_dir_name(
+        fd: __wasi_fd_t,
+        path: *mut c_char,
+        path_len: size_t,
+    ) -> __wasi_errno_t;
+}