diff --git a/std/os/wasi/core.zig b/std/os/wasi/core.zig
index 24a19c04fa..f2bef73be9 100644
--- a/std/os/wasi/core.zig
+++ b/std/os/wasi/core.zig
@@ -25,6 +25,13 @@ pub const device_t = u64;
 pub const dircookie_t = u64;
 pub const DIRCOOKIE_START: dircookie_t = 0;
 
+pub const dirent_t = extern struct {
+    d_next: dircookie_t,
+    d_ino: inode_t,
+    d_namlen: u32,
+    d_type: filetype_t,
+};
+
 pub const errno_t = u16;
 pub const ESUCCESS: errno_t = 0;
 pub const E2BIG: errno_t = 1;
@@ -104,6 +111,18 @@ pub const ETXTBSY: errno_t = 74;
 pub const EXDEV: errno_t = 75;
 pub const ENOTCAPABLE: errno_t = 76;
 
+pub const event_t = extern struct {
+    userdata: userdata_t,
+    @"error": errno_t,
+    @"type": eventtype_t,
+    u: extern union {
+        fd_readwrite: extern struct {
+            nbytes: filesize_t,
+            flags: eventrwflags_t,
+        },
+    },
+};
+
 pub const eventrwflags_t = u16;
 pub const EVENT_FD_READWRITE_HANGUP: eventrwflags_t = 0x0001;
 
@@ -123,10 +142,28 @@ pub const FDFLAG_NONBLOCK: fdflags_t = 0x0004;
 pub const FDFLAG_RSYNC: fdflags_t = 0x0008;
 pub const FDFLAG_SYNC: fdflags_t = 0x0010;
 
+const fdstat_t = extern struct {
+    fs_filetype: filetype_t,
+    fs_flags: fdflags_t,
+    fs_rights_base: rights_t,
+    fs_rights_inheriting: rights_t,
+};
+
 pub const filedelta_t = i64;
 
 pub const filesize_t = u64;
 
+pub const filestat_t = extern struct {
+    st_dev: device_t,
+    st_ino: inode_t,
+    st_filetype: filetype_t,
+    st_nlink: linkcount_t,
+    st_size: filesize_t,
+    st_atim: timestamp_t,
+    st_mtim: timestamp_t,
+    st_ctim: timestamp_t,
+};
+
 pub const filetype_t = u8;
 pub const FILETYPE_UNKNOWN: filetype_t = 0;
 pub const FILETYPE_BLOCK_DEVICE: filetype_t = 1;
@@ -145,6 +182,11 @@ pub const FILESTAT_SET_MTIM_NOW: fstflags_t = 0x0008;
 
 pub const inode_t = u64;
 
+pub const iovec_t = extern struct {
+    buf: [*]u8,
+    buf_len: usize,
+};
+
 pub const linkcount_t = u32;
 
 pub const lookupflags_t = u32;
@@ -156,6 +198,18 @@ pub const O_DIRECTORY: oflags_t = 0x0002;
 pub const O_EXCL: oflags_t = 0x0004;
 pub const O_TRUNC: oflags_t = 0x0008;
 
+pub const preopentype_t = u8;
+pub const PREOPENTYPE_DIR: preopentype_t = 0;
+
+pub const prestat_t = extern struct {
+    pr_type: preopentype_t,
+    u: extern union {
+        dir: extern struct {
+            pr_name_len: usize,
+        },
+    },
+};
+
 pub const riflags_t = u16;
 pub const SOCK_RECV_PEEK: riflags_t = 0x0001;
 pub const SOCK_RECV_WAITALL: riflags_t = 0x0002;
@@ -235,6 +289,23 @@ pub const SIGSYS: signal_t = 30;
 pub const subclockflags_t = u16;
 pub const SUBSCRIPTION_CLOCK_ABSTIME: subclockflags_t = 0x0001;
 
+pub const subscription_t = extern struct {
+    userdata: userdata_t,
+    @"type": eventtype_t,
+    u: extern union {
+        clock: extern struct {
+            identifier: userdata_t,
+            clock_id: clockid_t,
+            timeout: timestamp_t,
+            precision: timestamp_t,
+            flags: subclockflags_t,
+        },
+        fd_readwrite: extern struct {
+            fd: fd_t,
+        },
+    },
+};
+
 pub const timestamp_t = u64;
 
 pub const userdata_t = u64;
@@ -253,9 +324,51 @@ pub extern "wasi_unstable" fn clock_time_get(clock_id: clockid_t, precision: tim
 pub extern "wasi_unstable" fn environ_get(environ: [*]?[*]u8, environ_buf: [*]u8) errno_t;
 pub extern "wasi_unstable" fn environ_sizes_get(environ_count: *usize, environ_buf_size: *usize) errno_t;
 
-pub extern "wasi_unstable" fn proc_raise(sig: signal_t) errno_t;
-pub extern "wasi_unstable" fn proc_exit(rval: exitcode_t) noreturn;
-
+pub extern "wasi_unstable" fn fd_advise(fd: fd_t, offset: filesize_t, len: filesize_t, advice: advice_t) errno_t;
+pub extern "wasi_unstable" fn fd_allocate(fd: fd_t, offset: filesize_t, len: filesize_t) errno_t;
+pub extern "wasi_unstable" fn fd_close(fd: fd_t) errno_t;
+pub extern "wasi_unstable" fn fd_datasync(fd: fd_t) errno_t;
+pub extern "wasi_unstable" fn fd_pread(fd: fd_t, iovs: *const iovec_t, iovs_len: usize, offset: filesize_t, nread: *usize) errno_t;
+pub extern "wasi_unstable" fn fd_pwrite(fd: fd_t, iovs: *const ciovec_t, iovs_len: usize, offset: filesize_t, nwritten: *usize) errno_t;
+pub extern "wasi_unstable" fn fd_read(fd: fd_t, iovs: *const iovec_t, iovs_len: usize, nread: *usize) errno_t;
+pub extern "wasi_unstable" fn fd_readdir(fd: fd_t, buf: [*]u8, buf_len: usize, cookie: dircookie_t, bufused: *usize) errno_t;
+pub extern "wasi_unstable" fn fd_renumber(from: fd_t, to: fd_t) errno_t;
+pub extern "wasi_unstable" fn fd_seek(fd: fd_t, offset: filedelta_t, whence: whence_t, newoffset: *filesize_t) errno_t;
+pub extern "wasi_unstable" fn fd_sync(fd: fd_t) errno_t;
+pub extern "wasi_unstable" fn fd_tell(fd: fd_t, newoffset: *filesize_t) errno_t;
 pub extern "wasi_unstable" fn fd_write(fd: fd_t, iovs: *const ciovec_t, iovs_len: usize, nwritten: *usize) errno_t;
 
+pub extern "wasi_unstable" fn fd_fdstat_get(fd: fd_t, buf: *fdstat_t) errno_t;
+pub extern "wasi_unstable" fn fd_fdstat_set_flags(fd: fd_t, flags: fdflags_t) errno_t;
+pub extern "wasi_unstable" fn fd_fdstat_set_rights(fd: fd_t, fs_rights_base: rights_t, fs_rights_inheriting: rights_t) errno_t;
+
+pub extern "wasi_unstable" fn fd_filestat_get(fd: fd_t, buf: *filestat_t) errno_t;
+pub extern "wasi_unstable" fn fd_filestat_set_size(fd: fd_t, st_size: filesize_t) errno_t;
+pub extern "wasi_unstable" fn fd_filestat_set_times(fd: fd_t, st_atim: timestamp_t, st_mtim: timestamp_t, fstflags: fstflags_t) errno_t;
+
+pub extern "wasi_unstable" fn fd_prestat_get(fd: fd_t, buf: *prestat_t) errno_t;
+pub extern "wasi_unstable" fn fd_prestat_dir_name(fd: fd_t, path: [*]u8, path_len: usize) errno_t;
+
+pub extern "wasi_unstable" fn path_create_directory(fd: fd_t, path: [*]const u8, path_len: usize) errno_t;
+pub extern "wasi_unstable" fn path_filestat_get(fd: fd_t, flags: lookupflags_t, path: [*]const u8, path_len: usize, buf: *filestat_t) errno_t;
+pub extern "wasi_unstable" fn path_filestat_set_times(fd: fd_t, flags: lookupflags_t, path: [*]const u8, path_len: usize, st_atim: timestamp_t, st_mtim: timestamp_t, fstflags: fstflags_t) errno_t;
+pub extern "wasi_unstable" fn path_link(old_fd: fd_t, old_flags: lookupflags_t, old_path: [*]const u8, old_path_len: usize, new_fd: fd_t, new_path: [*]const u8, new_path_len: usize) errno_t;
+pub extern "wasi_unstable" fn path_open(dirfd: fd_t, dirflags: lookupflags_t, path: [*]const u8, path_len: usize, oflags: oflags_t, fs_rights_base: rights_t, fs_rights_inheriting: rights_t, fs_flags: fdflags_t, fd: *fd_t) errno_t;
+pub extern "wasi_unstable" fn path_readlink(fd: fd_t, path: [*]const u8, path_len: usize, buf: [*]u8, buf_len: usize, bufused: *usize) errno_t;
+pub extern "wasi_unstable" fn path_remove_directory(fd: fd_t, path: [*]const u8, path_len: usize) errno_t;
+pub extern "wasi_unstable" fn path_rename(old_fd: fd_t, old_path: [*]const u8, old_path_len: usize, new_fd: fd_t, new_path: [*]const u8, new_path_len: usize) errno_t;
+pub extern "wasi_unstable" fn path_symlink(old_path: [*]const u8, old_path_len: usize, fd: fd_t, new_path: [*]const u8, new_path_len: usize) errno_t;
+pub extern "wasi_unstable" fn path_unlink_file(fd: fd_t, path: [*]const u8, path_len: usize) errno_t;
+
+pub extern "wasi_unstable" fn poll_oneoff(in: *const subscription_t, out: *event_t, nsubscriptions: usize, nevents: *usize) errno_t;
+
+pub extern "wasi_unstable" fn proc_exit(rval: exitcode_t) noreturn;
+pub extern "wasi_unstable" fn proc_raise(sig: signal_t) errno_t;
+
 pub extern "wasi_unstable" fn random_get(buf: [*]u8, buf_len: usize) errno_t;
+
+pub extern "wasi_unstable" fn sched_yield() errno_t;
+
+pub extern "wasi_unstable" fn sock_recv(sock: fd_t, ri_data: *const iovec_t, ri_data_len: usize, ri_flags: riflags_t, ro_datalen: *usize, ro_flags: *roflags_t) errno_t;
+pub extern "wasi_unstable" fn sock_send(sock: fd_t, si_data: *const ciovec_t, si_data_len: usize, si_flags: siflags_t, so_datalen: *usize) errno_t;
+pub extern "wasi_unstable" fn sock_shutdown(sock: fd_t, how: sdflags_t) errno_t;