[CRIU] [PATCH RFC 02/30] files: Create per-process transport sock and bind it

[Andrei Vagin]

I think it would be better to explain why we need a per-process socket.

On Tue, Nov 01, 2016 at 05:30:36PM +0300, Kirill Tkhai wrote:
> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
> ---
>  criu/cr-restore.c    |    6 ------
>  criu/files.c         |   18 ++++++++++++++++--
>  criu/include/files.h |    2 --
>  3 files changed, 16 insertions(+), 10 deletions(-)
> 
> diff --git a/criu/cr-restore.c b/criu/cr-restore.c
> index 3abdea8..1b88dce 100644
> --- a/criu/cr-restore.c
> +++ b/criu/cr-restore.c
> @@ -270,10 +270,6 @@ static int root_prepare_shared(void)
>  	if (ret)
>  		goto err;
>  
> -	ret = open_transport_socket();
> -	if (ret)
> -		goto err;
> -
>  	show_saved_files();
>  err:
>  	return ret;
> @@ -714,8 +710,6 @@ static int restore_one_alive_task(int pid, CoreEntry *core)
>  	if (prepare_vmas(current, ta))
>  		return -1;
>  
> -	close_service_fd(TRANSPORT_FD_OFF);
> -
>  	if (setup_uffd(pid, ta))
>  		return -1;
>  
> diff --git a/criu/files.c b/criu/files.c
> index 21af891..e869614 100644
> --- a/criu/files.c
> +++ b/criu/files.c
> @@ -1149,6 +1149,8 @@ int close_old_fds(void)
>  	return 0;
>  }
>  
> +static int open_transport_socket(pid_t pid);
> +
>  int prepare_fds(struct pstree_item *me)
>  {
>  	u32 ret = 0;
> @@ -1183,6 +1185,9 @@ int prepare_fds(struct pstree_item *me)
>  		}
>  	}
>  
> +	if (open_transport_socket(me->pid.virt))
> +		return -1;
> +
>  	for (state = 0; state < ARRAY_SIZE(states); state++) {
>  		if (!states[state].required) {
>  			pr_debug("Skipping %s fd stage\n", states[state].name);
> @@ -1231,6 +1236,7 @@ int prepare_fds(struct pstree_item *me)
>  out_w:
>  	if (rsti(me)->fdt)
>  		futex_inc_and_wake(&rsti(me)->fdt->fdt_lock);
> +	close_service_fd(TRANSPORT_FD_OFF);
>  out:
>  	close_service_fd(CR_PROC_FD_OFF);
>  	tty_fini_fds();
> @@ -1663,15 +1669,23 @@ int inherit_fd_fini()
>  	return 0;
>  }
>  
> -int open_transport_socket()
> +static int open_transport_socket(pid_t pid)
>  {
> -	int sock;
> +	struct sockaddr_un saddr;
> +	int sock, slen;
>  
>  	sock = socket(PF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0);
>  	if (sock < 0) {
>  		pr_perror("Can't create socket");
>  		return -1;
>  	}
> +
> +	transport_name_gen(&saddr, &slen, pid, -1);
> +	if (bind(sock, (struct sockaddr *)&saddr, slen) < 0) {
> +		pr_perror("Can't bind transport socket %s", saddr.sun_path + 1);
> +		return -1;
> +	}
> +
>  	if (install_service_fd(TRANSPORT_FD_OFF, sock) < 0) {
>  		close(sock);
>  		return -1;
> diff --git a/criu/include/files.h b/criu/include/files.h
> index 153e7b3..2cd1a67 100644
> --- a/criu/include/files.h
> +++ b/criu/include/files.h
> @@ -189,6 +189,4 @@ extern FdinfoEntry *dup_fdinfo(FdinfoEntry *old, int fd, unsigned flags);
>  int dup_fle(struct pstree_item *task, struct fdinfo_list_entry *ple,
>  	    int fd, unsigned flags);
>  
> -extern int open_transport_socket(void);
> -
>  #endif /* __CR_FILES_H__ */
>