Method deliver_request

tpm/src/emulator.rs:310–377

Function to write to data socket and read the response from it

(&mut self, cmd: &mut BackendCmd)

    /// Function to write to data socket and read the response from it
    pub fn deliver_request(&mut self, cmd: &mut BackendCmd) -> Result<()> {
        // SAFETY: type "sockaddr_storage" is valid with an all-zero byte-pattern value
        let mut addr: sockaddr_storage = unsafe { mem::zeroed() };
        let mut len = mem::size_of::<sockaddr_storage>() as socklen_t;
        let isselftest = is_selftest(&cmd.buffer[0..cmd.input_len]);

        debug!(
            "Send cmd: {:02X?}  of len {:?} on data_ioc ",
            cmd.buffer, cmd.input_len
        );

        let mut data_vecs = [libc::iovec {
            iov_base: cmd.buffer.as_mut_ptr().cast(),
            iov_len: cmd.input_len,
        }; 1];

        // SAFETY: all zero values from the unsafe method are updated before usage
        let mut msghdr: libc::msghdr = unsafe { mem::zeroed() };
        msghdr.msg_name = ptr::null_mut();
        msghdr.msg_namelen = 0;
        msghdr.msg_iov = data_vecs.as_mut_ptr().cast();
        msghdr.msg_iovlen = data_vecs.len() as _;
        msghdr.msg_control = ptr::null_mut();
        msghdr.msg_controllen = 0;
        msghdr.msg_flags = 0;
        // SAFETY: FFI call and the return value of the unsafe method is checked
        unsafe {
            let ret = libc::sendmsg(self.data_fd, &msghdr, 0);
            if ret == -1 {
                return Err(Error::SendReceive(anyhow!(
                    "Failed to send tpm command over Data FD. Error Code {:?}",
                    std::io::Error::last_os_error()
                )));
            }
        }

        let output_len;
        // SAFETY: FFI calls and return value from unsafe method is checked
        unsafe {
            let ret = libc::recvfrom(
                self.data_fd,
                cmd.buffer.as_mut_ptr().cast(),
                cmd.buffer.len(),
                0,
                (&raw mut addr).cast(),
                &raw mut len,
            );
            if ret == -1 {
                return Err(Error::SendReceive(anyhow!(
                    "Failed to receive response for tpm command over Data FD. Error Code {:?}",
                    std::io::Error::last_os_error()
                )));
            }
            output_len = ret as usize;
        }
        debug!(
            "response = {:02X?} len = {:?} selftest = {:?}",
            cmd.buffer, output_len, isselftest