Rollup merge of #129638 - nickrum:wasip2-net, r=alexcrichton

Hook up std::net to wasi-libc on wasm32-wasip2 target

One of the improvements of the `wasm32-wasip2` target over `wasm32-wasip1` is better support for networking. Right now, p2 is just re-using the `std::net` implementation from p1. This PR adds a new net module for p2 that makes use of net from `sys_common` and calls wasi-libc functions directly.

There are currently a few limitations:

- Duplicating a socket is not supported by WASIp2 (directly returns an error)
- Peeking is not yet implemented in wasi-libc (we could let wasi-libc handle this, but I opted to directly return an error instead)
- Vectored reads/writes are not supported by WASIp2 (the necessary functions are available in wasi-libc, but they call WASIp1 functions which do not support sockets, so I opted to directly return an error instead)
- Getting/setting `TCP_NODELAY` is faked in wasi-libc (uses the fake implementation instead of returning an error)
- Getting/setting `SO_LINGER` is not supported by WASIp2 (directly returns an error)
- Setting `SO_REUSEADDR` is faked in wasi-libc (since this is done from `sys_common`, the fake implementation is used instead of returning an error)
- Getting/setting `IPV6_V6ONLY` is not supported by WASIp2 and will always be set for IPv6 sockets (since this is done from `sys_common`, wasi-libc will return an error)
- UDP broadcast/multicast is not supported by WASIp2 (since this is configured from `sys_common`, wasi-libc will return appropriate errors)
- The `MSG_NOSIGNAL` send flag is a no-op because there are no signals in WASIp2 (since explicitly setting this flag would require a change to `sys_common` and the result would be exactly the same, I opted to not set it)

Do those decisions make sense?

While working on this PR, I noticed that there is a `std::os::wasi::net::TcpListenerExt` trait that adds a `sock_accept()` method to `std::net::TcpListener`. Now that WASIp2 supports standard accept, would it make sense to remove this?

cc `@alexcrichton`

1 files changed, 7 insertions, 2 deletions

diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index 4805e598ce2..75659f46431 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -1370,7 +1370,7 @@ Executed at: {executed_at}"#,
         }
 
         if target.starts_with("wasm") && target.contains("wasi") {
-            self.default_wasi_runner()
+            self.default_wasi_runner(target)
         } else {
             None
         }
@@ -1379,7 +1379,7 @@ Executed at: {executed_at}"#,
     /// When a `runner` configuration is not provided and a WASI-looking target
     /// is being tested this is consulted to prove the environment to see if
     /// there's a runtime already lying around that seems reasonable to use.
-    fn default_wasi_runner(&self) -> Option<String> {
+    fn default_wasi_runner(&self, target: TargetSelection) -> Option<String> {
         let mut finder = crate::core::sanity::Finder::new();
 
         // Look for Wasmtime, and for its default options be sure to disable
@@ -1395,6 +1395,11 @@ Executed at: {executed_at}"#,
                 // inherit the entire environment rather than just this single
                 // environment variable.
                 path.push_str(" --env RUSTC_BOOTSTRAP");
+
+                if target.contains("wasip2") {
+                    path.push_str(" --wasi inherit-network --wasi allow-ip-name-lookup");
+                }
+
                 return Some(path);
             }
         }