[CRIU] Re: [PATCH 4/4] cr-restore: read pages to temporary file if migrating

[Pavel Emelyanov]

On 08/15/2012 01:54 PM, Adrian Reber wrote:
> This is a hack until it is possible to read the pages-*.img directly
> from restorer.c over a network socket. This workaround opens
> a temporary file on /dev/shm which is then used by restorer.c to
> read pages-*.img.

I don't see any code, that closes one and then removes. 

> Signed-off-by: Adrian Reber <adrian at lisas.de>
> ---
>  cr-restore.c |   51 +++++++++++++++++++++++++++++++++++++++++++--------
>  1 files changed, 43 insertions(+), 8 deletions(-)
> 
> diff --git a/cr-restore.c b/cr-restore.c
> index fe07599..f9b8c88 100644
> --- a/cr-restore.c
> +++ b/cr-restore.c
> @@ -1171,7 +1171,6 @@ static int sigreturn_restore(pid_t pid, CoreEntry *core, struct list_head *tgt_v
>  	struct thread_restore_args *thread_args;
>  
>  	LIST_HEAD(self_vma_list);
> -	int fd_pages = -1;
>  	int i;
>  
>  	pr_info("Restore via sigreturn\n");
> @@ -1195,12 +1194,6 @@ static int sigreturn_restore(pid_t pid, CoreEntry *core, struct list_head *tgt_v
>  	BUILD_BUG_ON(SHMEMS_SIZE % PAGE_SIZE);
>  	BUILD_BUG_ON(TASK_ENTRIES_SIZE % PAGE_SIZE);
>  
> -	fd_pages = open_image_ro(CR_FD_PAGES, pid);
> -	if (fd_pages < 0) {
> -		pr_perror("Can't open pages-%d", pid);
> -		goto err;
> -	}
> -
>  	restore_code_len	= sizeof(restorer_blob);
>  	restore_code_len	= round_up(restore_code_len, 16);
>  
> @@ -1315,7 +1308,6 @@ static int sigreturn_restore(pid_t pid, CoreEntry *core, struct list_head *tgt_v
>  	task_args->pid		= pid;
>  	task_args->logfd	= log_get_fd();
>  	task_args->sigchld_act	= sigchld_act;
> -	task_args->fd_pages	= fd_pages;
>  
>  	strncpy(task_args->comm, core->tc->comm, sizeof(task_args->comm));
>  
> @@ -1339,6 +1331,49 @@ static int sigreturn_restore(pid_t pid, CoreEntry *core, struct list_head *tgt_v
>  	if (ret < 0)
>  		goto err;
>  
> +	task_args->fd_pages = open_image_ro(CR_FD_PAGES, pid);
> +	if (task_args->fd_pages < 0) {
> +		pr_perror("Can't open pages-%d", pid);
> +		goto err;
> +	}
> +
> +	/* check if we are running in network migration mode */
> +	if (open_listen_socket(NULL, 0) >= 0) {
> +		/* yes we are. save the pages to temporary file
> +		 * until there is a better way to directly read
> +		 * the network socket from restorer.c */
> +
> +		int tmp_fd;
> +		char buffer[PATH_MAX];
> +		char tmp[PAGE_SIZE];
> +		int n;
> +
> +		i = 0;
> +		strcpy(buffer, "/dev/shm/pages-XXXXXX");
> +		tmp_fd = mkstemp(buffer);
> +		while (1) {
> +			n = read(task_args->fd_pages, tmp, PAGE_SIZE);
> +
> +			if (n == 0)
> +				break;
> +
> +			if (n == -1) {
> +				pr_perror("Pages read failed");
> +				goto err;
> +			}
> +
> +			i = write(tmp_fd, tmp, n);
> +			if (i!=n) {
> +				pr_perror("Oops, writing failed");
> +				goto err;
> +			}
> +
> +		}
> +		lseek(tmp_fd, 0, SEEK_SET);
> +		close(task_args->fd_pages);
> +		task_args->fd_pages = tmp_fd;
> +	}
> +
>  	mutex_init(&task_args->rst_lock);
>  
>  	/*