Add sendmsg/recvmsg support for unix domain socket

src/libos/src/net/socket/unix/stream/stream.rs

@@ -5,6 +5,7 @@ use events::{Event, EventFilter, Notifier, Observer};
 use fs::channel::Channel;
 use fs::IoEvents;
 use fs::{CreationFlags, FileMode};
+use net::socket::{Iovs, MsgHdr, MsgHdrMut};
 use std::fmt;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Arc;
@@ -223,6 +224,32 @@ impl Stream {
         Ok((data_len, addr))
     }
 
+    pub fn sendmsg(&self, msg_hdr: &MsgHdr, flags: SendFlags) -> Result<usize> {
+        if !flags.is_empty() {
+            warn!("unsupported flags: {:?}", flags);
+        }
+        if msg_hdr.get_control().is_some() {
+            warn!("sendmsg with msg_control is not supported");
+        }
+
+        let bufs = msg_hdr.get_iovs().as_slices();
+        self.writev(bufs)
+    }
+
+    pub fn recvmsg(&self, msg_hdr: &mut MsgHdrMut, flags: RecvFlags) -> Result<usize> {
+        if !flags.is_empty() {
+            warn!("unsupported flags: {:?}", flags);
+        }
+
+        let bufs = msg_hdr.get_iovs_mut().as_slices_mut();
+        let data_len = self.readv(bufs)?;
+
+        // For stream socket, the msg_name is ignored. And other fields are not supported.
+        msg_hdr.set_name_len(0);
+
+        Ok(data_len)
+    }
+
     /// perform shutdown on the socket.
     pub fn shutdown(&self, how: HowToShut) -> Result<()> {
         if let Status::Connected(ref end) = &*self.inner() {

src/libos/src/net/syscalls.rs

@@ -489,23 +489,27 @@ pub fn do_sendmsg(fd: c_int, msg_ptr: *const msghdr, flags_c: c_int) -> Result<i
         fd, msg_ptr, flags_c
     );
 
-    let file_ref = current!().file(fd as FileDesc)?;
-    if let Ok(socket) = file_ref.as_host_socket() {
-        let msg_c = {
+    let msg_hdr = {
+        let msg_hdr_c = {
             from_user::check_ptr(msg_ptr)?;
-            let msg_c = unsafe { &*msg_ptr };
-            msg_c.check_member_ptrs()?;
-            msg_c
+            let msg_hdr_c = unsafe { &*msg_ptr };
+            msg_hdr_c.check_member_ptrs()?;
+            msg_hdr_c
+        };
+        unsafe { MsgHdr::from_c(&msg_hdr_c)? }
     };
-        let msg = unsafe { MsgHdr::from_c(&msg_c)? };
 
     let flags = SendFlags::from_bits_truncate(flags_c);
 
+    let file_ref = current!().file(fd as FileDesc)?;
+    if let Ok(socket) = file_ref.as_host_socket() {
         socket
-            .sendmsg(&msg, flags)
+            .sendmsg(&msg_hdr, flags)
             .map(|bytes_sent| bytes_sent as isize)
     } else if let Ok(socket) = file_ref.as_unix_socket() {
-        return_errno!(EOPNOTSUPP, "does not support unix socket")
+        socket
+            .sendmsg(&msg_hdr, flags)
+            .map(|bytes_sent| bytes_sent as isize)
     } else {
         return_errno!(ENOTSOCK, "not a socket")
     }
@@ -517,23 +521,27 @@ pub fn do_recvmsg(fd: c_int, msg_mut_ptr: *mut msghdr_mut, flags_c: c_int) -> Re
         fd, msg_mut_ptr, flags_c
     );
 
-    let file_ref = current!().file(fd as FileDesc)?;
-    if let Ok(socket) = file_ref.as_host_socket() {
-        let msg_mut_c = {
+    let mut msg_hdr_mut = {
+        let msg_hdr_mut_c = {
             from_user::check_mut_ptr(msg_mut_ptr)?;
-            let msg_mut_c = unsafe { &mut *msg_mut_ptr };
-            msg_mut_c.check_member_ptrs()?;
-            msg_mut_c
+            let msg_hdr_mut_c = unsafe { &mut *msg_mut_ptr };
+            msg_hdr_mut_c.check_member_ptrs()?;
+            msg_hdr_mut_c
+        };
+        unsafe { MsgHdrMut::from_c(msg_hdr_mut_c) }?
     };
-        let mut msg_mut = unsafe { MsgHdrMut::from_c(msg_mut_c)? };
 
     let flags = RecvFlags::from_bits_truncate(flags_c);
 
+    let file_ref = current!().file(fd as FileDesc)?;
+    if let Ok(socket) = file_ref.as_host_socket() {
         socket
-            .recvmsg(&mut msg_mut, flags)
+            .recvmsg(&mut msg_hdr_mut, flags)
             .map(|bytes_recvd| bytes_recvd as isize)
     } else if let Ok(socket) = file_ref.as_unix_socket() {
-        return_errno!(EOPNOTSUPP, "does not support unix socket")
+        socket
+            .recvmsg(&mut msg_hdr_mut, flags)
+            .map(|bytes_recvd| bytes_recvd as isize)
     } else {
         return_errno!(ENOTSOCK, "not a socket")
     }

test/unix_socket/main.c

@@ -465,6 +465,99 @@ int test_epoll_wait() {
     return 0;
 }
 
+int client_sendmsg(int server_fd, char *buf) {
+    int ret = 0;
+    struct msghdr msg;
+    struct iovec iov[1];
+    msg.msg_name = NULL;
+    msg.msg_namelen = 0;
+    iov[0].iov_base = buf;
+    iov[0].iov_len = strlen(buf);
+    msg.msg_iov = iov;
+    msg.msg_iovlen = 1;
+    msg.msg_control = 0;
+    msg.msg_controllen = 0;
+    msg.msg_flags = 0;
+
+    ret = sendmsg(server_fd, &msg, 0);
+    if (ret <= 0) {
+        THROW_ERROR("sendmsg failed");
+    }
+
+    msg.msg_iov = NULL;
+    msg.msg_iovlen = 0;
+
+    ret = sendmsg(server_fd, &msg, 0);
+    if (ret != 0) {
+        THROW_ERROR("empty sendmsg failed");
+    }
+    return ret;
+}
+
+
+int server_recvmsg(int client_fd) {
+    int ret = 0;
+    const int buf_size = 10;
+    char buf[3][buf_size];
+    struct msghdr msg;
+    struct iovec iov[3];
+    char result_buf[] = {ECHO_MSG}; // 30 bytes
+
+    memset(&msg, 0, sizeof(struct msghdr));
+    msg.msg_name  = NULL;
+    msg.msg_namelen  = 0;
+    iov[0].iov_base = buf[0];
+    iov[0].iov_len = buf_size;
+    iov[1].iov_base = buf[1];
+    iov[1].iov_len = buf_size;
+    iov[2].iov_base = buf[2];
+    iov[2].iov_len = buf_size;
+    msg.msg_iov = iov;
+    msg.msg_iovlen = 3;
+    msg.msg_control = 0;
+    msg.msg_controllen = 0;
+    msg.msg_flags = 0;
+
+    ret = recvmsg(client_fd, &msg, 0);
+    if (ret <= 0) {
+        THROW_ERROR("recvmsg failed");
+    } else {
+        if (strncmp(buf[0], result_buf, buf_size) != 0 &&
+                strncmp(buf[1], result_buf + buf_size, buf_size) != 0 &&
+                strncmp(buf[0], result_buf + buf_size * 2, buf_size) != 0) {
+            printf("recvmsg : %d, msg: %s,  %s, %s\n", ret, buf[0], buf[1], buf[2]);
+            THROW_ERROR("msg recvmsg mismatch");
+        }
+    }
+    return ret;
+}
+
+int test_sendmsg_recvmsg() {
+    int ret = 0;
+    char test_buf[] = {ECHO_MSG};
+    int socks[2];
+
+    ret = socketpair(AF_UNIX, SOCK_STREAM, 0, socks);
+    if (ret < 0) {
+        THROW_ERROR("socket pair create failed");
+    }
+
+    int server_fd = socks[0];
+    int client_fd = socks[1];
+
+    ret = client_sendmsg(server_fd, test_buf);
+    if (ret < 0) {
+        THROW_ERROR("client_sendmsg failed");
+    }
+
+    ret = server_recvmsg(client_fd);
+    if (ret < 0) {
+        THROW_ERROR("server_recvmsg failed");
+    }
+
+    return ret;
+}
+
 static test_case_t test_cases[] = {
     TEST_CASE(test_unix_socket_inter_process),
     TEST_CASE(test_socketpair_inter_process),
@@ -474,6 +567,7 @@ static test_case_t test_cases[] = {
     TEST_CASE(test_ioctl_fionread),
     TEST_CASE(test_unix_socket_rename),
     TEST_CASE(test_epoll_wait),
+    TEST_CASE(test_sendmsg_recvmsg),
 };
 
 int main(int argc, const char *argv[]) {