1 files changed, 323 insertions, 0 deletions
diff --git a/library/std/src/sys/sgx/abi/usercalls/mod.rs b/library/std/src/sys/sgx/abi/usercalls/mod.rs
new file mode 100644
index 000000000..79d1db5e1
--- /dev/null
+++ b/library/std/src/sys/sgx/abi/usercalls/mod.rs
@@ -0,0 +1,323 @@
+use crate::cmp;
+use crate::io::{Error as IoError, ErrorKind, IoSlice, IoSliceMut, Result as IoResult};
+use crate::sys::rand::rdrand64;
+use crate::time::{Duration, Instant};
+
+pub(crate) mod alloc;
+#[macro_use]
+pub(crate) mod raw;
+#[cfg(test)]
+mod tests;
+
+use self::raw::*;
+
+/// Usercall `read`. See the ABI documentation for more information.
+///
+/// This will do a single `read` usercall and scatter the read data among
+/// `bufs`. To read to a single buffer, just pass a slice of length one.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn read(fd: Fd, bufs: &mut [IoSliceMut<'_>]) -> IoResult<usize> {
+    unsafe {
+        let total_len = bufs.iter().fold(0usize, |sum, buf| sum.saturating_add(buf.len()));
+        let mut userbuf = alloc::User::<[u8]>::uninitialized(total_len);
+        let ret_len = raw::read(fd, userbuf.as_mut_ptr(), userbuf.len()).from_sgx_result()?;
+        let userbuf = &userbuf[..ret_len];
+        let mut index = 0;
+        for buf in bufs {
+            let end = cmp::min(index + buf.len(), userbuf.len());
+            if let Some(buflen) = end.checked_sub(index) {
+                userbuf[index..end].copy_to_enclave(&mut buf[..buflen]);
+                index += buf.len();
+            } else {
+                break;
+            }
+        }
+        Ok(userbuf.len())
+    }
+}
+
+/// Usercall `read_alloc`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn read_alloc(fd: Fd) -> IoResult<Vec<u8>> {
+    unsafe {
+        let userbuf = ByteBuffer { data: crate::ptr::null_mut(), len: 0 };
+        let mut userbuf = alloc::User::new_from_enclave(&userbuf);
+        raw::read_alloc(fd, userbuf.as_raw_mut_ptr()).from_sgx_result()?;
+        Ok(userbuf.copy_user_buffer())
+    }
+}
+
+/// Usercall `write`. See the ABI documentation for more information.
+///
+/// This will do a single `write` usercall and gather the written data from
+/// `bufs`. To write from a single buffer, just pass a slice of length one.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn write(fd: Fd, bufs: &[IoSlice<'_>]) -> IoResult<usize> {
+    unsafe {
+        let total_len = bufs.iter().fold(0usize, |sum, buf| sum.saturating_add(buf.len()));
+        let mut userbuf = alloc::User::<[u8]>::uninitialized(total_len);
+        let mut index = 0;
+        for buf in bufs {
+            let end = cmp::min(index + buf.len(), userbuf.len());
+            if let Some(buflen) = end.checked_sub(index) {
+                userbuf[index..end].copy_from_enclave(&buf[..buflen]);
+                index += buf.len();
+            } else {
+                break;
+            }
+        }
+        raw::write(fd, userbuf.as_ptr(), userbuf.len()).from_sgx_result()
+    }
+}
+
+/// Usercall `flush`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn flush(fd: Fd) -> IoResult<()> {
+    unsafe { raw::flush(fd).from_sgx_result() }
+}
+
+/// Usercall `close`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn close(fd: Fd) {
+    unsafe { raw::close(fd) }
+}
+
+fn string_from_bytebuffer(buf: &alloc::UserRef<ByteBuffer>, usercall: &str, arg: &str) -> String {
+    String::from_utf8(buf.copy_user_buffer())
+        .unwrap_or_else(|_| rtabort!("Usercall {usercall}: expected {arg} to be valid UTF-8"))
+}
+
+/// Usercall `bind_stream`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn bind_stream(addr: &str) -> IoResult<(Fd, String)> {
+    unsafe {
+        let addr_user = alloc::User::new_from_enclave(addr.as_bytes());
+        let mut local = alloc::User::<ByteBuffer>::uninitialized();
+        let fd = raw::bind_stream(addr_user.as_ptr(), addr_user.len(), local.as_raw_mut_ptr())
+            .from_sgx_result()?;
+        let local = string_from_bytebuffer(&local, "bind_stream", "local_addr");
+        Ok((fd, local))
+    }
+}
+
+/// Usercall `accept_stream`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn accept_stream(fd: Fd) -> IoResult<(Fd, String, String)> {
+    unsafe {
+        let mut bufs = alloc::User::<[ByteBuffer; 2]>::uninitialized();
+        let mut buf_it = alloc::UserRef::iter_mut(&mut *bufs); // FIXME: can this be done
+        // without forcing coercion?
+        let (local, peer) = (buf_it.next().unwrap(), buf_it.next().unwrap());
+        let fd = raw::accept_stream(fd, local.as_raw_mut_ptr(), peer.as_raw_mut_ptr())
+            .from_sgx_result()?;
+        let local = string_from_bytebuffer(&local, "accept_stream", "local_addr");
+        let peer = string_from_bytebuffer(&peer, "accept_stream", "peer_addr");
+        Ok((fd, local, peer))
+    }
+}
+
+/// Usercall `connect_stream`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn connect_stream(addr: &str) -> IoResult<(Fd, String, String)> {
+    unsafe {
+        let addr_user = alloc::User::new_from_enclave(addr.as_bytes());
+        let mut bufs = alloc::User::<[ByteBuffer; 2]>::uninitialized();
+        let mut buf_it = alloc::UserRef::iter_mut(&mut *bufs); // FIXME: can this be done
+        // without forcing coercion?
+        let (local, peer) = (buf_it.next().unwrap(), buf_it.next().unwrap());
+        let fd = raw::connect_stream(
+            addr_user.as_ptr(),
+            addr_user.len(),
+            local.as_raw_mut_ptr(),
+            peer.as_raw_mut_ptr(),
+        )
+        .from_sgx_result()?;
+        let local = string_from_bytebuffer(&local, "connect_stream", "local_addr");
+        let peer = string_from_bytebuffer(&peer, "connect_stream", "peer_addr");
+        Ok((fd, local, peer))
+    }
+}
+
+/// Usercall `launch_thread`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub unsafe fn launch_thread() -> IoResult<()> {
+    // SAFETY: The caller must uphold the safety contract for `launch_thread`.
+    unsafe { raw::launch_thread().from_sgx_result() }
+}
+
+/// Usercall `exit`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn exit(panic: bool) -> ! {
+    unsafe { raw::exit(panic) }
+}
+
+/// Usercall `wait`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn wait(event_mask: u64, mut timeout: u64) -> IoResult<u64> {
+    if timeout != WAIT_NO && timeout != WAIT_INDEFINITE {
+        // We don't want people to rely on accuracy of timeouts to make
+        // security decisions in an SGX enclave. That's why we add a random
+        // amount not exceeding +/- 10% to the timeout value to discourage
+        // people from relying on accuracy of timeouts while providing a way
+        // to make things work in other cases. Note that in the SGX threat
+        // model the enclave runner which is serving the wait usercall is not
+        // trusted to ensure accurate timeouts.
+        if let Ok(timeout_signed) = i64::try_from(timeout) {
+            let tenth = timeout_signed / 10;
+            let deviation = (rdrand64() as i64).checked_rem(tenth).unwrap_or(0);
+            timeout = timeout_signed.saturating_add(deviation) as _;
+        }
+    }
+    unsafe { raw::wait(event_mask, timeout).from_sgx_result() }
+}
+
+/// This function makes an effort to wait for a non-spurious event at least as
+/// long as `duration`. Note that in general there is no guarantee about accuracy
+/// of time and timeouts in SGX model. The enclave runner serving usercalls may
+/// lie about current time and/or ignore timeout values.
+///
+/// Once the event is observed, `should_wake_up` will be used to determine
+/// whether or not the event was spurious.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn wait_timeout<F>(event_mask: u64, duration: Duration, should_wake_up: F)
+where
+    F: Fn() -> bool,
+{
+    // Calls the wait usercall and checks the result. Returns true if event was
+    // returned, and false if WouldBlock/TimedOut was returned.
+    // If duration is None, it will use WAIT_NO.
+    fn wait_checked(event_mask: u64, duration: Option<Duration>) -> bool {
+        let timeout = duration.map_or(raw::WAIT_NO, |duration| {
+            cmp::min((u64::MAX - 1) as u128, duration.as_nanos()) as u64
+        });
+        match wait(event_mask, timeout) {
+            Ok(eventset) => {
+                if event_mask == 0 {
+                    rtabort!("expected wait() to return Err, found Ok.");
+                }
+                rtassert!(eventset != 0 && eventset & !event_mask == 0);
+                true
+            }
+            Err(e) => {
+                rtassert!(e.kind() == ErrorKind::TimedOut || e.kind() == ErrorKind::WouldBlock);
+                false
+            }
+        }
+    }
+
+    match wait_checked(event_mask, Some(duration)) {
+        false => return,                    // timed out
+        true if should_wake_up() => return, // woken up
+        true => {}                          // spurious event
+    }
+
+    // Drain all cached events.
+    // Note that `event_mask != 0` is implied if we get here.
+    loop {
+        match wait_checked(event_mask, None) {
+            false => break,                     // no more cached events
+            true if should_wake_up() => return, // woken up
+            true => {}                          // spurious event
+        }
+    }
+
+    // Continue waiting, but take note of time spent waiting so we don't wait
+    // forever. We intentionally don't call `Instant::now()` before this point
+    // to avoid the cost of the `insecure_time` usercall in case there are no
+    // spurious wakeups.
+
+    let start = Instant::now();
+    let mut remaining = duration;
+    loop {
+        match wait_checked(event_mask, Some(remaining)) {
+            false => return,                    // timed out
+            true if should_wake_up() => return, // woken up
+            true => {}                          // spurious event
+        }
+        remaining = match duration.checked_sub(start.elapsed()) {
+            Some(remaining) => remaining,
+            None => break,
+        }
+    }
+}
+
+/// Usercall `send`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn send(event_set: u64, tcs: Option<Tcs>) -> IoResult<()> {
+    unsafe { raw::send(event_set, tcs).from_sgx_result() }
+}
+
+/// Usercall `insecure_time`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn insecure_time() -> Duration {
+    let t = unsafe { raw::insecure_time() };
+    Duration::new(t / 1_000_000_000, (t % 1_000_000_000) as _)
+}
+
+/// Usercall `alloc`. See the ABI documentation for more information.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn alloc(size: usize, alignment: usize) -> IoResult<*mut u8> {
+    unsafe { raw::alloc(size, alignment).from_sgx_result() }
+}
+
+#[unstable(feature = "sgx_platform", issue = "56975")]
+#[doc(inline)]
+pub use self::raw::free;
+
+fn check_os_error(err: Result) -> i32 {
+    // FIXME: not sure how to make sure all variants of Error are covered
+    if err == Error::NotFound as _
+        || err == Error::PermissionDenied as _
+        || err == Error::ConnectionRefused as _
+        || err == Error::ConnectionReset as _
+        || err == Error::ConnectionAborted as _
+        || err == Error::NotConnected as _
+        || err == Error::AddrInUse as _
+        || err == Error::AddrNotAvailable as _
+        || err == Error::BrokenPipe as _
+        || err == Error::AlreadyExists as _
+        || err == Error::WouldBlock as _
+        || err == Error::InvalidInput as _
+        || err == Error::InvalidData as _
+        || err == Error::TimedOut as _
+        || err == Error::WriteZero as _
+        || err == Error::Interrupted as _
+        || err == Error::Other as _
+        || err == Error::UnexpectedEof as _
+        || ((Error::UserRangeStart as _)..=(Error::UserRangeEnd as _)).contains(&err)
+    {
+        err
+    } else {
+        rtabort!("Usercall: returned invalid error value {err}")
+    }
+}
+
+trait FromSgxResult {
+    type Return;
+
+    fn from_sgx_result(self) -> IoResult<Self::Return>;
+}
+
+impl<T> FromSgxResult for (Result, T) {
+    type Return = T;
+
+    fn from_sgx_result(self) -> IoResult<Self::Return> {
+        if self.0 == RESULT_SUCCESS {
+            Ok(self.1)
+        } else {
+            Err(IoError::from_raw_os_error(check_os_error(self.0)))
+        }
+    }
+}
+
+impl FromSgxResult for Result {
+    type Return = ();
+
+    fn from_sgx_result(self) -> IoResult<Self::Return> {
+        if self == RESULT_SUCCESS {
+            Ok(())
+        } else {
+            Err(IoError::from_raw_os_error(check_os_error(self)))
+        }
+    }
+}