chore(proxy): vendor a subset of rust-postgres (#9930)

Our rust-postgres fork is getting messy. Mostly because proxy wants more
control over the raw protocol than tokio-postgres provides. As such,
it's diverging more and more. Storage and compute also make use of
rust-postgres, but in more normal usage, thus they don't need our crazy
changes.

Idea: 
* proxy maintains their subset
* other teams use a minimal patch set against upstream rust-postgres

Reviewing this code will be difficult. To implement it, I
1. Copied tokio-postgres, postgres-protocol and postgres-types from
00940fcdb5
2. Updated their package names with the `2` suffix to make them compile
in the workspace.
3. Updated proxy to use those packages
4. Copied in the code from tokio-postgres-rustls 0.13 (with some patches
applied https://github.com/jbg/tokio-postgres-rustls/pull/32
https://github.com/jbg/tokio-postgres-rustls/pull/33)
5. Removed as much dead code as I could find in the vendored libraries
6. Updated the tokio-postgres-rustls code to use our existing channel
binding implementation

libs/proxy/postgres-protocol2/src/message/frontend.rs

@@ -0,0 +1,297 @@
+//! Frontend message serialization.
+#![allow(missing_docs)]
+
+use byteorder::{BigEndian, ByteOrder};
+use bytes::{Buf, BufMut, BytesMut};
+use std::convert::TryFrom;
+use std::error::Error;
+use std::io;
+use std::marker;
+
+use crate::{write_nullable, FromUsize, IsNull, Oid};
+
+#[inline]
+fn write_body<F, E>(buf: &mut BytesMut, f: F) -> Result<(), E>
+where
+    F: FnOnce(&mut BytesMut) -> Result<(), E>,
+    E: From<io::Error>,
+{
+    let base = buf.len();
+    buf.extend_from_slice(&[0; 4]);
+
+    f(buf)?;
+
+    let size = i32::from_usize(buf.len() - base)?;
+    BigEndian::write_i32(&mut buf[base..], size);
+    Ok(())
+}
+
+pub enum BindError {
+    Conversion(Box<dyn Error + marker::Sync + Send>),
+    Serialization(io::Error),
+}
+
+impl From<Box<dyn Error + marker::Sync + Send>> for BindError {
+    #[inline]
+    fn from(e: Box<dyn Error + marker::Sync + Send>) -> BindError {
+        BindError::Conversion(e)
+    }
+}
+
+impl From<io::Error> for BindError {
+    #[inline]
+    fn from(e: io::Error) -> BindError {
+        BindError::Serialization(e)
+    }
+}
+
+#[inline]
+pub fn bind<I, J, F, T, K>(
+    portal: &str,
+    statement: &str,
+    formats: I,
+    values: J,
+    mut serializer: F,
+    result_formats: K,
+    buf: &mut BytesMut,
+) -> Result<(), BindError>
+where
+    I: IntoIterator<Item = i16>,
+    J: IntoIterator<Item = T>,
+    F: FnMut(T, &mut BytesMut) -> Result<IsNull, Box<dyn Error + marker::Sync + Send>>,
+    K: IntoIterator<Item = i16>,
+{
+    buf.put_u8(b'B');
+
+    write_body(buf, |buf| {
+        write_cstr(portal.as_bytes(), buf)?;
+        write_cstr(statement.as_bytes(), buf)?;
+        write_counted(
+            formats,
+            |f, buf| {
+                buf.put_i16(f);
+                Ok::<_, io::Error>(())
+            },
+            buf,
+        )?;
+        write_counted(
+            values,
+            |v, buf| write_nullable(|buf| serializer(v, buf), buf),
+            buf,
+        )?;
+        write_counted(
+            result_formats,
+            |f, buf| {
+                buf.put_i16(f);
+                Ok::<_, io::Error>(())
+            },
+            buf,
+        )?;
+
+        Ok(())
+    })
+}
+
+#[inline]
+fn write_counted<I, T, F, E>(items: I, mut serializer: F, buf: &mut BytesMut) -> Result<(), E>
+where
+    I: IntoIterator<Item = T>,
+    F: FnMut(T, &mut BytesMut) -> Result<(), E>,
+    E: From<io::Error>,
+{
+    let base = buf.len();
+    buf.extend_from_slice(&[0; 2]);
+    let mut count = 0;
+    for item in items {
+        serializer(item, buf)?;
+        count += 1;
+    }
+    let count = i16::from_usize(count)?;
+    BigEndian::write_i16(&mut buf[base..], count);
+
+    Ok(())
+}
+
+#[inline]
+pub fn cancel_request(process_id: i32, secret_key: i32, buf: &mut BytesMut) {
+    write_body(buf, |buf| {
+        buf.put_i32(80_877_102);
+        buf.put_i32(process_id);
+        buf.put_i32(secret_key);
+        Ok::<_, io::Error>(())
+    })
+    .unwrap();
+}
+
+#[inline]
+pub fn close(variant: u8, name: &str, buf: &mut BytesMut) -> io::Result<()> {
+    buf.put_u8(b'C');
+    write_body(buf, |buf| {
+        buf.put_u8(variant);
+        write_cstr(name.as_bytes(), buf)
+    })
+}
+
+pub struct CopyData<T> {
+    buf: T,
+    len: i32,
+}
+
+impl<T> CopyData<T>
+where
+    T: Buf,
+{
+    pub fn new(buf: T) -> io::Result<CopyData<T>> {
+        let len = buf
+            .remaining()
+            .checked_add(4)
+            .and_then(|l| i32::try_from(l).ok())
+            .ok_or_else(|| {
+                io::Error::new(io::ErrorKind::InvalidInput, "message length overflow")
+            })?;
+
+        Ok(CopyData { buf, len })
+    }
+
+    pub fn write(self, out: &mut BytesMut) {
+        out.put_u8(b'd');
+        out.put_i32(self.len);
+        out.put(self.buf);
+    }
+}
+
+#[inline]
+pub fn copy_done(buf: &mut BytesMut) {
+    buf.put_u8(b'c');
+    write_body(buf, |_| Ok::<(), io::Error>(())).unwrap();
+}
+
+#[inline]
+pub fn copy_fail(message: &str, buf: &mut BytesMut) -> io::Result<()> {
+    buf.put_u8(b'f');
+    write_body(buf, |buf| write_cstr(message.as_bytes(), buf))
+}
+
+#[inline]
+pub fn describe(variant: u8, name: &str, buf: &mut BytesMut) -> io::Result<()> {
+    buf.put_u8(b'D');
+    write_body(buf, |buf| {
+        buf.put_u8(variant);
+        write_cstr(name.as_bytes(), buf)
+    })
+}
+
+#[inline]
+pub fn execute(portal: &str, max_rows: i32, buf: &mut BytesMut) -> io::Result<()> {
+    buf.put_u8(b'E');
+    write_body(buf, |buf| {
+        write_cstr(portal.as_bytes(), buf)?;
+        buf.put_i32(max_rows);
+        Ok(())
+    })
+}
+
+#[inline]
+pub fn parse<I>(name: &str, query: &str, param_types: I, buf: &mut BytesMut) -> io::Result<()>
+where
+    I: IntoIterator<Item = Oid>,
+{
+    buf.put_u8(b'P');
+    write_body(buf, |buf| {
+        write_cstr(name.as_bytes(), buf)?;
+        write_cstr(query.as_bytes(), buf)?;
+        write_counted(
+            param_types,
+            |t, buf| {
+                buf.put_u32(t);
+                Ok::<_, io::Error>(())
+            },
+            buf,
+        )?;
+        Ok(())
+    })
+}
+
+#[inline]
+pub fn password_message(password: &[u8], buf: &mut BytesMut) -> io::Result<()> {
+    buf.put_u8(b'p');
+    write_body(buf, |buf| write_cstr(password, buf))
+}
+
+#[inline]
+pub fn query(query: &str, buf: &mut BytesMut) -> io::Result<()> {
+    buf.put_u8(b'Q');
+    write_body(buf, |buf| write_cstr(query.as_bytes(), buf))
+}
+
+#[inline]
+pub fn sasl_initial_response(mechanism: &str, data: &[u8], buf: &mut BytesMut) -> io::Result<()> {
+    buf.put_u8(b'p');
+    write_body(buf, |buf| {
+        write_cstr(mechanism.as_bytes(), buf)?;
+        let len = i32::from_usize(data.len())?;
+        buf.put_i32(len);
+        buf.put_slice(data);
+        Ok(())
+    })
+}
+
+#[inline]
+pub fn sasl_response(data: &[u8], buf: &mut BytesMut) -> io::Result<()> {
+    buf.put_u8(b'p');
+    write_body(buf, |buf| {
+        buf.put_slice(data);
+        Ok(())
+    })
+}
+
+#[inline]
+pub fn ssl_request(buf: &mut BytesMut) {
+    write_body(buf, |buf| {
+        buf.put_i32(80_877_103);
+        Ok::<_, io::Error>(())
+    })
+    .unwrap();
+}
+
+#[inline]
+pub fn startup_message<'a, I>(parameters: I, buf: &mut BytesMut) -> io::Result<()>
+where
+    I: IntoIterator<Item = (&'a str, &'a str)>,
+{
+    write_body(buf, |buf| {
+        // postgres protocol version 3.0(196608) in bigger-endian
+        buf.put_i32(0x00_03_00_00);
+        for (key, value) in parameters {
+            write_cstr(key.as_bytes(), buf)?;
+            write_cstr(value.as_bytes(), buf)?;
+        }
+        buf.put_u8(0);
+        Ok(())
+    })
+}
+
+#[inline]
+pub fn sync(buf: &mut BytesMut) {
+    buf.put_u8(b'S');
+    write_body(buf, |_| Ok::<(), io::Error>(())).unwrap();
+}
+
+#[inline]
+pub fn terminate(buf: &mut BytesMut) {
+    buf.put_u8(b'X');
+    write_body(buf, |_| Ok::<(), io::Error>(())).unwrap();
+}
+
+#[inline]
+fn write_cstr(s: &[u8], buf: &mut BytesMut) -> Result<(), io::Error> {
+    if s.contains(&0) {
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidInput,
+            "string contains embedded null",
+        ));
+    }
+    buf.put_slice(s);
+    buf.put_u8(0);
+    Ok(())
+}