[CRIU] [PATCH] pstree: Avoid multiple calls to getpid()

[Dmitry Safonov]

On 10/28/18 8:42 PM, Radostin Stoyanov wrote:
> Signed-off-by: Radostin Stoyanov <rstoyanov1 at gmail.com>

Reviewed-by: Dmitry Safonov <0x7f454c46 at gmail.com>

> ---
>   criu/pstree.c | 18 ++++++++++--------
>   1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/criu/pstree.c b/criu/pstree.c
> index 928fe2d1..980d19fd 100644
> --- a/criu/pstree.c
> +++ b/criu/pstree.c
> @@ -333,10 +333,10 @@ err:
>   	return ret;
>   }
>   
> -static int prepare_pstree_for_shell_job(void)
> +static int prepare_pstree_for_shell_job(pid_t current_pid)
>   {
> -	pid_t current_sid = getsid(getpid());
> -	pid_t current_gid = getpgid(getpid());
> +	pid_t current_sid = getsid(current_pid);
> +	pid_t current_gid = getpgid(current_pid);
>   
>   	struct pstree_item *pi;
>   
> @@ -625,12 +625,12 @@ static int get_free_pid()
>   	return -1;
>   }
>   
> -static int prepare_pstree_ids(void)
> +static int prepare_pstree_ids(pid_t current_pid)
>   {
>   	struct pstree_item *item, *child, *helper, *tmp;
>   	LIST_HEAD(helpers);
>   
> -	pid_t current_pgid = getpgid(getpid());
> +	pid_t current_pgid = getpgid(current_pid);
>   
>   	/*
>   	 * Some task can be reparented to init. A helper task should be added
> @@ -910,7 +910,7 @@ static int prepare_pstree_kobj_ids(void)
>   int prepare_pstree(void)
>   {
>   	int ret;
> -	pid_t pid_max = 0, kpid_max = 0;
> +	pid_t pid_max = 0, kpid_max = 0, current_pid;
>   	int fd;
>   	char buf[21];
>   
> @@ -945,12 +945,14 @@ int prepare_pstree(void)
>   		}
>   	}
>   
> +	current_pid = getpid();
> +
>   	if (!ret)
>   		/*
>   		 * Shell job may inherit sid/pgid from the current
>   		 * shell, not from image. Set things up for this.
>   		 */
> -		ret = prepare_pstree_for_shell_job();
> +		ret = prepare_pstree_for_shell_job(current_pid);
>   	if (!ret)
>   		/*
>   		 * Walk the collected tree and prepare for restoring
> @@ -962,7 +964,7 @@ int prepare_pstree(void)
>   		 * Session/Group leaders might be dead. Need to fix
>   		 * pstree with properly injected helper tasks.
>   		 */
> -		ret = prepare_pstree_ids();
> +		ret = prepare_pstree_ids(current_pid);
>   
>   	return ret;
>   }
> 

Thanks,
           Dima