[CRIU] [PATCH v5 2/5] mount: Create binfmt_misc image w/o device suffix

[Pavel Emelyanov]

On 08/04/2016 04:49 PM, Kirill Tkhai wrote:
> Use name binfmt_misc-0.img for any mounted binfmt_misc.
> Note, that newly created binfmt_misc images won't restore
> on old criu.
> 
> Also, because of above, let's change a behaviour of dump and now
> we do not create binfmt_misc images if there is no registered
> binfmt_misc entries.
> 
> v5: New
> Suggested-by: Pavel Emelyanov <xemul at virtuozzo.com>
> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
> ---
>  criu/mount.c |   40 ++++++++++++++++++++++++++++++++--------
>  1 file changed, 32 insertions(+), 8 deletions(-)
> 
> diff --git a/criu/mount.c b/criu/mount.c
> index f90ec69..c5533de 100644
> --- a/criu/mount.c
> +++ b/criu/mount.c
> @@ -1361,7 +1361,7 @@ static int dump_binfmt_misc_entry(int dfd, char *name, struct cr_img *img)
>  
>  static int binfmt_misc_dump(struct mount_info *pm)
>  {
> -	struct cr_img *img;
> +	struct cr_img *img = NULL;
>  	struct dirent *de;
>  	DIR *fdir = NULL;
>  	int fd, ret;
> @@ -1381,10 +1381,6 @@ static int binfmt_misc_dump(struct mount_info *pm)
>  	}
>  
>  	ret = -1;
> -	img = open_image(CR_FD_BINFMT_MISC, O_DUMP, pm->s_dev);
> -	if (!img)
> -		goto out;
> -
>  	while ((de = readdir(fdir))) {
>  		if (dir_dots(de))
>  			continue;
> @@ -1393,6 +1389,13 @@ static int binfmt_misc_dump(struct mount_info *pm)
>  		if (!strcmp(de->d_name, "status"))
>  			continue;
>  
> +		if (!img) {
> +			/* Create image only if an extry exists, i.e. here */
> +			img = open_image(CR_FD_BINFMT_MISC, O_DUMP, 0);

Let's change the name format and remove 0 from it.

> +			if (!img)
> +				goto out;
> +		}
> +
>  		if (dump_binfmt_misc_entry(fd, de->d_name, img))
>  			goto out;
>  	}
> @@ -1487,20 +1490,41 @@ static int make_bfmtm_magic_str(char *buf, BinfmtMiscEntry *bme)
>  
>  static int binfmt_misc_restore(struct mount_info *mi)
>  {
> +	unsigned int suffix;
>  	struct cr_img *img;
> +	struct stat st;
>  	char *buf;
> -	int ret = -1;
> +	int ret;
>  
>  	buf = xmalloc(BINFMT_MISC_STR);
>  	if (!buf)
>  		return -1;
>  
> -	img = open_image(CR_FD_BINFMT_MISC, O_RSTR, mi->s_dev);
> +	suffix = 0;
> +	ret = stat_image(CR_FD_BINFMT_MISC, &st, suffix);

There's no need to stat the image. Just do it like we did before -- try
to open image by legacy name and, if it's empty_image(), try to open
by new name.

> +	if (ret < 0) {
> +		if (ret == -ENOENT) {
> +			suffix = mi->s_dev;
> +			ret = stat_image(CR_FD_BINFMT_MISC, &st, suffix);
> +			if (ret == -ENOENT) {
> +				ret = 0;
> +				pr_info("No binfmt image found\n");
> +				goto free_buf;
> +			}
> +		}
> +		else if (ret) {
> +			pr_err("Can't stat binfmt_misc image: %s\n", strerror(ret));
> +			goto free_buf;
> +		}
> +	}
> +
> +	img = open_image(CR_FD_BINFMT_MISC, O_RSTR, suffix);
>  	if (!img) {
> +		pr_err("Can't open binfmt_misc image\n");
> +		ret = -1;
>  		goto free_buf;
>  	}
>  
> -	ret = 0;
>  	while (ret == 0) {
>  		BinfmtMiscEntry *bme;
>  
> 
> _______________________________________________
> CRIU mailing list
> CRIU at openvz.org
> https://lists.openvz.org/mailman/listinfo/criu
> .
>