[CRIU] Re: [PATCH 4/6] restore: Add file owners restoring

[Pavel Emelyanov]

On 04/10/2012 12:03 AM, Cyrill Gorcunov wrote:
> The base idea is trivial, once file descriptor
> created the owner is read and set up.
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
>  files.c         |   46 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/files.h |    2 ++
>  pipes.c         |    3 +++
>  3 files changed, 51 insertions(+), 0 deletions(-)
> 
> diff --git a/files.c b/files.c
> index 53ab115..28cf1ff 100644
> --- a/files.c
> +++ b/files.c
> @@ -103,6 +103,49 @@ void show_saved_files(void)
>  		}
>  }
>  
> +int restore_fown(pid_t pid, int fd, fown_t *fown)

pid as argument is not required.

> +{
> +	struct f_owner_ex owner;
> +	uid_t uids[3];
> +
> +	if (fown->signum) {
> +		if (fcntl(fd, F_SETSIG, fown->signum)) {
> +			pr_perror("%d: Can't set signal", pid);
> +			return -1;
> +		}
> +	}
> +
> +	/* May be untouched */
> +	if (!fown->pid)
> +		return 0;
> +
> +	if (getresuid(&uids[0], &uids[1], &uids[2])) {
> +		pr_perror("%d: Can't get UIDs", pid);
> +		return -1;
> +	}
> +
> +	if (setresuid(fown->uid, fown->euid, uids[2])) {
> +		pr_perror("%d: Can't set UIDs", pid);
> +		return -1;
> +	}
> +
> +	owner.type = fown->pid_type;
> +	owner.pid = fown->pid;
> +
> +	if (fcntl(fd, F_SETOWN_EX, &owner)) {
> +		pr_perror("%d: Can't setup %d file owner pid",
> +			  pid, fd);
> +		return -1;
> +	}
> +
> +	if (setresuid(uids[0], uids[1], uids[2])) {
> +		pr_perror("%d: Can't set UIDs", pid);

"Can't reset UIDs back" or smth like this.

> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
>  static struct reg_file_info *find_reg_file(int id)
>  {
>  	struct file_desc *fd;
> @@ -245,6 +288,9 @@ static int open_fe_fd(struct file_desc *d)
>  
>  	lseek(tmp, rfi->rfe.pos, SEEK_SET);
>  
> +	if (restore_fown(getpid(), tmp, &rfi->rfe.fown))
> +		return -1;
> +
>  	return tmp;
>  }
>  static int find_open_fe_fd(struct fdinfo_entry *fe)
> diff --git a/include/files.h b/include/files.h
> index 5d63db6..c1f1c32 100644
> --- a/include/files.h
> +++ b/include/files.h
> @@ -74,4 +74,6 @@ struct file_desc;
>  extern int collect_pipes(void);
>  extern void mark_pipe_master(void);
>  
> +extern int restore_fown(pid_t pid, int fd, fown_t *fown);
> +
>  #endif /* FILES_H_ */
> diff --git a/pipes.c b/pipes.c
> index 2b18b92..868d895 100644
> --- a/pipes.c
> +++ b/pipes.c
> @@ -315,5 +315,8 @@ out:
>  	if (ret < 0)
>  		return -1;
>  
> +	if (restore_fown(getpid(), tmp, &pi->pe.fown))
> +		return -1;
> +
>  	return tmp;
>  }