[CRIU] [PATCH] image: do_open_remote_image: Move the unix sockets to workdir

[Mike Rapoport]

On Tue, Jul 18, 2017 at 09:08:01AM +0300, Pavel Emelyanov wrote:
> On 07/17/2017 09:49 PM, Omri Kramer wrote:
> > It's better to open the unix sockets for dump and restore
> > inside the workdir. See TODO item 1 in:
> > https://github.com/xemul/criu/commit/037b2e3c95e098d63a3500834681543da544840e
> > 
> > Signed-off-by: Omri Kramer <omri.kramer at gmail.com>
> > Signed-off-by: Lior Fisch <fischlior at gmail.com>
> > ---
> >  criu/image.c             | 32 +++++++++++++++++++++++++++++++-
> >  criu/include/servicefd.h |  1 +
> >  2 files changed, 32 insertions(+), 1 deletion(-)
> > 
> > diff --git a/criu/image.c b/criu/image.c
> > index 62e8e71..7c21178 100644
> > --- a/criu/image.c
> > +++ b/criu/image.c
> > @@ -338,7 +338,7 @@ int do_open_remote_image(int dfd, char *path, int flags)
> >  		return -1;
> >  	}
> >  
> > -	if (fchdir(get_service_fd(IMG_FD_OFF)) < 0) {
> > +	if (fchdir(get_service_fd(WRK_FD_OFF)) < 0) {
> >  		pr_perror("fchdir to dfd failed!");
> >  		close(save);
> >  		return -1;
> > @@ -465,6 +465,32 @@ struct cr_img *img_from_fd(int fd)
> >  	return img;
> >  }
> >  
> > +static void close_work_dir(void)
> > +{
> > +	close_service_fd(WRK_FD_OFF);
> > +}
> > +
> > +static int open_work_dir(char *dir)
> > +{
> > +	int fd;
> > +
> > +	fd = open(dir, O_RDONLY);
> > +	if (fd < 0) {
> > +		pr_perror("Can't open dir %s", dir);
> > +		return -1;
> > +	}
> > +
> > +	if (install_service_fd(WRK_FD_OFF, fd) < 0) {
> > +		pr_perror("Can't install work_fd\n");
> > +		close(fd);
> > +		return -1;
> > +	}
> 
> Right now all the code in criu assumes, that workdir is cwd. Why do we
> need to introduce a service descriptor for that?

I haven't really dig into this, but I believe it's related to re-mounting
of the directories and namespace changing.
The img-{proxy,cache} are started before all the mount/namespace changes
and the UNIX socket they create in the default namespace is not visible
afterwards.
 
> > +
> > +	close(fd);
> > +	
> > +	return 0;
> > +}
> > +
> >  int open_image_dir(char *dir)
> >  {
> >  	int fd, ret;
> > @@ -481,6 +507,8 @@ int open_image_dir(char *dir)
> >  
> >  	if (opts.remote) {
> >  		init_snapshot_id(dir);
> > +		if (open_work_dir(opts.work_dir) < 0)
> > +			goto err;
> >  	} else if (opts.img_parent) {
> >  		ret = symlinkat(opts.img_parent, fd, CR_PARENT_LINK);
> >  		if (ret < 0 && errno != EEXIST) {
> > @@ -503,6 +531,8 @@ err:
> >  void close_image_dir(void)
> >  {
> >  	close_service_fd(IMG_FD_OFF);
> > +	if(opts.remote)
> > +		close_work_dir();
> >  }
> >  
> >  static unsigned long page_ids = 1;
> > diff --git a/criu/include/servicefd.h b/criu/include/servicefd.h
> > index b779223..66e4aeb 100644
> > --- a/criu/include/servicefd.h
> > +++ b/criu/include/servicefd.h
> > @@ -8,6 +8,7 @@ enum sfd_type {
> >  
> >  	LOG_FD_OFF,
> >  	IMG_FD_OFF,
> > +	WRK_FD_OFF,
> >  	PROC_FD_OFF,	/* fd with /proc for all proc_ calls */
> >  	PROC_PID_FD_OFF,
> >  	CTL_TTY_OFF,
> > 
> 
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> 

-- 
Sincerely yours,
Mike.