[CRIU] Re: [PATCH 2/4] image: add functions to close and re-open the network listen socket

[Pavel Emelyanov]

On 08/15/2012 01:54 PM, Adrian Reber wrote:
> During the restore of the file descriptors all open network
> sockets have to be closed.

I don't quite understand this requirement. Can you elaborate, please?

> The network hostname and port are stored during open_listen_socket()
> and after close_listen_socket() they can be re-used by calling
> reopen_listen_socket().
> 
> Signed-off-by: Adrian Reber <adrian at lisas.de>
> ---
>  image.c           |   28 ++++++++++++++++++++++++++++
>  include/crtools.h |    2 ++
>  2 files changed, 30 insertions(+), 0 deletions(-)
> 
> diff --git a/image.c b/image.c
> index 2115412..969017a 100644
> --- a/image.c
> +++ b/image.c
> @@ -218,6 +218,8 @@ struct cr_fdset *cr_glob_fdset_open(int mode)
>  
>  static int image_dir_fd = -1;
>  static int sockfd = -1;
> +static char network_host[255] = "";
> +static int network_port = -1;
>  
>  int open_image(int type, unsigned long flags, ...)
>  {
> @@ -309,6 +311,15 @@ int open_listen_socket(char *host, int port)
>  	struct hostent *server;
>  	struct sockaddr_in serveraddr;
>  
> +	if (sockfd != -1)
> +		return sockfd;
> +
> +	/* if host is not specified return early */
> +	if (host == NULL)
> +		return -1;
> +
> +	pr_info("Listening on %s:%d\n", host, port);
> +
>  	sockfd = socket(AF_INET, SOCK_STREAM, 0);
>  	if (sockfd < 0) {
>  		pr_perror("ERROR opening socket");
> @@ -336,5 +347,22 @@ int open_listen_socket(char *host, int port)
>  		return -1;
>  	}
>  
> +	strncpy(network_host, host, 255);
> +	network_port = port;
>  	return sockfd;
>  }
> +
> +void close_listen_socket()
> +{
> +	if (sockfd == -1)
> +		return;
> +	close_safe(&sockfd);
> +	sockfd = -1;
> +}
> +
> +int reopen_listen_socket()
> +{
> +	if (network_port != -1)
> +		return open_listen_socket(network_host, network_port);
> +	return 0;
> +}
> diff --git a/include/crtools.h b/include/crtools.h
> index c2ccbe0..c092802 100644
> --- a/include/crtools.h
> +++ b/include/crtools.h
> @@ -133,6 +133,8 @@ extern int open_image_dir(void);
>  extern void close_image_dir(void);
>  
>  extern int open_listen_socket(char *host, int port);
> +extern void close_listen_socket();
> +extern int reopen_listen_socket();
>  
>  int open_image(int type, unsigned long flags, ...);
>  #define open_image_ro(type, ...) open_image(type, O_RDONLY, ##__VA_ARGS__)