[CRIU] [PATCH 03/11] files: split collect_fd on allocate_fd and handle_fd

[Andrew Vagin]

On Wed, Feb 08, 2017 at 12:34:34PM +0300, Pavel Emelyanov wrote:
> On 02/02/2017 03:04 AM, Andrei Vagin wrote:
> > From: Andrew Vagin <avagin at virtuozzo.com>
> > 
> > We are going to open root directories for each namespace in
> > the root task, so we need to collect all file descriptors to
> > be able to find unused file descriptors.
> 
> OK, but why can't we use service-fd for the root dir?

Because we need to open all network namespaces (more than one)

> 
> > Signed-off-by: Andrei Vagin <avagin at virtuozzo.com>
> > ---
> >  criu/cr-restore.c    | 18 ++++++++++++++++++
> >  criu/files.c         | 50 +++++++++++++++++++++++++++++++++++++++++---------
> >  criu/include/files.h |  1 +
> >  3 files changed, 60 insertions(+), 9 deletions(-)
> > 
> > diff --git a/criu/cr-restore.c b/criu/cr-restore.c
> > index 53eb6b4..ba8ee57 100644
> > --- a/criu/cr-restore.c
> > +++ b/criu/cr-restore.c
> > @@ -1323,6 +1323,21 @@ static int create_children_and_session(void)
> >  	return 0;
> >  }
> >  
> > +static int collect_fd_shared()
> > +{
> > +	struct pstree_item *pi;
> > +
> > +	for_each_pstree_item(pi) {
> > +		if (pi->pid->state == TASK_HELPER)
> > +			continue;
> > +
> > +		if  (collect_fd_pid(pi))
> > +			return -1;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> >  static int restore_task_with_children(void *_arg)
> >  {
> >  	struct cr_clone_arg *ca = _arg;
> > @@ -1410,6 +1425,9 @@ static int restore_task_with_children(void *_arg)
> >  		pr_info("Calling restore_sid() for init\n");
> >  		restore_sid();
> >  
> > +		if (collect_fd_shared())
> > +			goto err;
> > +
> >  		/*
> >  		 * We need non /proc proc mount for restoring pid and mount
> >  		 * namespaces and do not care for the rest of the cases.
> > diff --git a/criu/files.c b/criu/files.c
> > index 1a76313..4ef75b3 100644
> > --- a/criu/files.c
> > +++ b/criu/files.c
> > @@ -686,19 +686,28 @@ int rst_file_params(int fd, FownEntry *fown, int flags)
> >  	return 0;
> >  }
> >  
> > -static int collect_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
> > +static struct fdinfo_list_entry *allocate_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
> >  {
> > -	struct fdinfo_list_entry *le, *new_le;
> > -	struct file_desc *fdesc;
> > +	struct fdinfo_list_entry *new_le;
> >  
> >  	pr_info("Collect fdinfo pid=%d fd=%d id=%#x\n",
> >  		pid, e->fd, e->id);
> >  
> >  	new_le = shmalloc(sizeof(*new_le));
> >  	if (!new_le)
> > -		return -1;
> > +		return NULL;
> >  
> >  	fle_init(new_le, pid, e);
> > +	collect_task_fd(new_le, rst_info);
> > +
> > +	return new_le;
> > +}
> > +
> > +static int handle_fd(struct fdinfo_list_entry *new_le, struct rst_info *rst_info)
> > +{
> > +	struct fdinfo_list_entry *le;
> > +	struct file_desc *fdesc;
> > +	FdinfoEntry *e = new_le->fe;
> >  
> >  	fdesc = find_file_desc(e);
> >  	if (fdesc == NULL) {
> > @@ -713,14 +722,23 @@ static int collect_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
> >  	if (fdesc->ops->collect_fd)
> >  		fdesc->ops->collect_fd(fdesc, new_le, rst_info);
> >  
> > -	collect_task_fd(new_le, rst_info);
> > -
> >  	list_add_tail(&new_le->desc_list, &le->desc_list);
> >  	new_le->desc = fdesc;
> >  
> >  	return 0;
> >  }
> >  
> > +static int collect_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
> > +{
> > +	struct fdinfo_list_entry *le;
> > +
> > +	le = allocate_fd(pid, e, rst_info);
> > +	if (le == NULL)
> > +		return -1;
> > +
> > +	return handle_fd(le, rst_info);
> > +}
> > +
> >  FdinfoEntry *dup_fdinfo(FdinfoEntry *old, int fd, unsigned flags)
> >  {
> >  	FdinfoEntry *e;
> > @@ -777,7 +795,7 @@ int prepare_ctl_tty(int pid, struct rst_info *rst_info, u32 ctl_tty_id)
> >  	return 0;
> >  }
> >  
> > -int prepare_fd_pid(struct pstree_item *item)
> > +int collect_fd_pid(struct pstree_item *item)
> >  {
> >  	int ret = 0;
> >  	struct cr_img *img;
> > @@ -798,6 +816,7 @@ int prepare_fd_pid(struct pstree_item *item)
> >  		return -1;
> >  
> >  	while (1) {
> > +		struct fdinfo_list_entry *le;
> >  		FdinfoEntry *e;
> >  
> >  		ret = pb_read_one_eof(img, &e, PB_FDINFO);
> > @@ -810,9 +829,10 @@ int prepare_fd_pid(struct pstree_item *item)
> >  			break;
> >  		}
> >  
> > -		ret = collect_fd(pid, e, rst_info);
> > -		if (ret < 0) {
> > +		le = allocate_fd(pid, e, rst_info);
> > +		if (le == NULL) {
> >  			fdinfo_entry__free_unpacked(e, NULL);
> > +			ret = -1;
> >  			break;
> >  		}
> >  	}
> > @@ -821,6 +841,18 @@ int prepare_fd_pid(struct pstree_item *item)
> >  	return ret;
> >  }
> >  
> > +int prepare_fd_pid(struct pstree_item *item)
> > +{
> > +	struct rst_info *rst_info = rsti(item);
> > +	struct fdinfo_list_entry *le, *t;
> > +	list_for_each_entry_safe(le, t, &rst_info->fds, ps_list) {
> > +		if (handle_fd(le, rst_info))
> > +			return -1;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> >  #define SETFL_MASK (O_APPEND | O_ASYNC | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
> >  int set_fd_flags(int fd, int flags)
> >  {
> > diff --git a/criu/include/files.h b/criu/include/files.h
> > index 39ef23b..f1216a1 100644
> > --- a/criu/include/files.h
> > +++ b/criu/include/files.h
> > @@ -156,6 +156,7 @@ extern int rst_file_params(int fd, FownEntry *fown, int flags);
> >  extern void show_saved_files(void);
> >  
> >  extern int prepare_fds(struct pstree_item *me);
> > +extern int collect_fd_pid(struct pstree_item *me);
> >  extern int prepare_fd_pid(struct pstree_item *me);
> >  extern int prepare_ctl_tty(int pid, struct rst_info *rst_info, u32 ctl_tty_id);
> >  extern int prepare_shared_fdinfo(void);
> > 
>