Re: [PATCH net-next 1/5] vsock/test: add recv_buf() utility function

[Arseniy Krasnov]

On 15.09.2023 15:14, Stefano Garzarella wrote:
> Move the code of recv_byte() out in a new utility function that
> can be used to receive a generic buffer.
> 
> This new function can be used when we need to receive a custom
> buffer and not just a single 'A' byte.
> 
> Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
> ---
>  tools/testing/vsock/util.h |  1 +
>  tools/testing/vsock/util.c | 88 +++++++++++++++++++++++---------------
>  2 files changed, 54 insertions(+), 35 deletions(-)

Reviewed-by: Arseniy Krasnov <avkrasnov@xxxxxxxxxxxxxxxxx>

> 
> diff --git a/tools/testing/vsock/util.h b/tools/testing/vsock/util.h
> index fb99208a95ea..fe31f267e67e 100644
> --- a/tools/testing/vsock/util.h
> +++ b/tools/testing/vsock/util.h
> @@ -42,6 +42,7 @@ int vsock_stream_accept(unsigned int cid, unsigned int port,
>  int vsock_seqpacket_accept(unsigned int cid, unsigned int port,
>  			   struct sockaddr_vm *clientaddrp);
>  void vsock_wait_remote_close(int fd);
> +void recv_buf(int fd, void *buf, size_t len, int flags, ssize_t expected_ret);
>  void send_byte(int fd, int expected_ret, int flags);
>  void recv_byte(int fd, int expected_ret, int flags);
>  void run_tests(const struct test_case *test_cases,
> diff --git a/tools/testing/vsock/util.c b/tools/testing/vsock/util.c
> index 01b636d3039a..2826902706e8 100644
> --- a/tools/testing/vsock/util.c
> +++ b/tools/testing/vsock/util.c
> @@ -211,6 +211,58 @@ int vsock_seqpacket_accept(unsigned int cid, unsigned int port,
>  	return vsock_accept(cid, port, clientaddrp, SOCK_SEQPACKET);
>  }
>  
> +/* Receive bytes in a buffer and check the return value.
> + *
> + * expected_ret:
> + *  <0 Negative errno (for testing errors)
> + *   0 End-of-file
> + *  >0 Success (bytes successfully read)
> + */
> +void recv_buf(int fd, void *buf, size_t len, int flags, ssize_t expected_ret)
> +{
> +	ssize_t nread = 0;
> +	ssize_t ret;
> +
> +	timeout_begin(TIMEOUT);
> +	do {
> +		ret = recv(fd, buf + nread, len - nread, flags);
> +		timeout_check("recv");
> +
> +		if (ret == 0 || (ret < 0 && errno != EINTR))
> +			break;
> +
> +		nread += ret;
> +	} while (nread < len);
> +	timeout_end();
> +
> +	if (expected_ret < 0) {
> +		if (ret != -1) {
> +			fprintf(stderr, "bogus recv(2) return value %zd (expected %zd)\n",
> +				ret, expected_ret);
> +			exit(EXIT_FAILURE);
> +		}
> +		if (errno != -expected_ret) {
> +			perror("recv");
> +			exit(EXIT_FAILURE);
> +		}
> +		return;
> +	}
> +
> +	if (ret < 0) {
> +		perror("recv");
> +		exit(EXIT_FAILURE);
> +	}
> +
> +	if (nread != expected_ret) {
> +		if (ret == 0)
> +			fprintf(stderr, "unexpected EOF while receiving bytes\n");
> +
> +		fprintf(stderr, "bogus recv(2) bytes read %zd (expected %zd)\n",
> +			nread, expected_ret);
> +		exit(EXIT_FAILURE);
> +	}
> +}
> +
>  /* Transmit one byte and check the return value.
>   *
>   * expected_ret:
> @@ -270,43 +322,9 @@ void send_byte(int fd, int expected_ret, int flags)
>  void recv_byte(int fd, int expected_ret, int flags)
>  {
>  	uint8_t byte;
> -	ssize_t nread;
> -
> -	timeout_begin(TIMEOUT);
> -	do {
> -		nread = recv(fd, &byte, sizeof(byte), flags);
> -		timeout_check("read");
> -	} while (nread < 0 && errno == EINTR);
> -	timeout_end();
> -
> -	if (expected_ret < 0) {
> -		if (nread != -1) {
> -			fprintf(stderr, "bogus recv(2) return value %zd\n",
> -				nread);
> -			exit(EXIT_FAILURE);
> -		}
> -		if (errno != -expected_ret) {
> -			perror("read");
> -			exit(EXIT_FAILURE);
> -		}
> -		return;
> -	}
>  
> -	if (nread < 0) {
> -		perror("read");
> -		exit(EXIT_FAILURE);
> -	}
> -	if (nread == 0) {
> -		if (expected_ret == 0)
> -			return;
> +	recv_buf(fd, &byte, sizeof(byte), flags, expected_ret);
>  
> -		fprintf(stderr, "unexpected EOF while receiving byte\n");
> -		exit(EXIT_FAILURE);
> -	}
> -	if (nread != sizeof(byte)) {
> -		fprintf(stderr, "bogus recv(2) return value %zd\n", nread);
> -		exit(EXIT_FAILURE);
> -	}
>  	if (byte != 'A') {
>  		fprintf(stderr, "unexpected byte read %c\n", byte);
>  		exit(EXIT_FAILURE);