[CRIU] [PATCH 04/14] crtools: add ability to create and close a service fd

[Pavel Emelyanov]

On 01/11/2013 01:22 PM, Andrey Vagin wrote:
> A service fd should be created, otherwise get_service_fd returns -1
> 
> v2: rename open_service_fd to install_service_fd
> 
> Signed-off-by: Andrey Vagin <avagin at openvz.org>
> ---
>  include/crtools.h |  2 ++
>  util.c            | 35 +++++++++++++++++++++++++++++++++++
>  2 files changed, 37 insertions(+)
> 
> diff --git a/include/crtools.h b/include/crtools.h
> index 64e11dd..a8813b3 100644
> --- a/include/crtools.h
> +++ b/include/crtools.h
> @@ -124,6 +124,8 @@ enum sfd_type {
>  extern int clone_service_fd(int id);
>  extern int init_service_fd(void);
>  extern int get_service_fd(enum sfd_type type);
> +extern int open_service_fd(enum sfd_type type, int fd);
> +extern int close_service_fd(enum sfd_type type);
>  extern bool is_service_fd(int fd, enum sfd_type type);
>  extern bool is_any_service_fd(int fd);
>  
> diff --git a/util.c b/util.c
> index af191d4..1ad0572 100644
> --- a/util.c
> +++ b/util.c
> @@ -308,12 +308,47 @@ static int __get_service_fd(enum sfd_type type, int service_fd_id)
>  	return service_fd_rlim_cur - type - SERVICE_FD_MAX * service_fd_id;
>  }
>  
> +static DECLARE_BITMAP(sfd_map, SERVICE_FD_MAX);
> +
> +int install_service_fd(enum sfd_type type, int fd)
> +{
> +	int sfd = __get_service_fd(type, service_fd_id);
> +
> +	BUG_ON((int)type <= SERVICE_FD_MIN || (int)type >= SERVICE_FD_MAX);
> +
> +	if (dup2(fd, sfd) != sfd) {
> +		pr_perror("Dup %d -> %d failed", fd, sfd);
> +		return -1;
> +	}
> +
> +	set_bit(type, sfd_map);
> +	return sfd;
> +}
> +
>  int get_service_fd(enum sfd_type type)
>  {
>  	BUG_ON((int)type <= SERVICE_FD_MIN || (int)type >= SERVICE_FD_MAX);
> +
> +	if (!test_bit(type, sfd_map))
> +		return -1;

This breaks git-bisect, isn't it? I mean -- right after this patch no
service fds will be available.

> +
>  	return __get_service_fd(type, service_fd_id);
>  }
>  
> +int close_service_fd(enum sfd_type type)
> +{
> +	int fd = get_service_fd(type);
> +
> +	if (fd < 0)
> +		return 0;
> +
> +	if (close_safe(&fd))
> +		return -1;
> +
> +	clear_bit(type, sfd_map);
> +	return 0;
> +}
> +
>  int clone_service_fd(int id)
>  {
>  	int ret = -1, i;
>