[CRIU] [PATCH v3 1/3] criu: dump loginuid & oom_score_adj values

[Andrew Vagin]

On Tue, Dec 08, 2015 at 06:11:55PM +0300, Dmitry Safonov wrote:
> https://jira.sw.ru/browse/PSBM-41993
> 
> Signed-off-by: Dmitry Safonov <dsafonov at odin.com>
> ---
>  cr-dump.c            | 32 ++++++++++++++++++++++++++++++++
>  include/proc_parse.h |  2 ++
>  proc_parse.c         | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  protobuf/core.proto  |  5 +++++
>  4 files changed, 91 insertions(+)
> 
> diff --git a/cr-dump.c b/cr-dump.c
> index 5cc375d..e76071c 100644
> --- a/cr-dump.c
> +++ b/cr-dump.c
> @@ -323,6 +323,34 @@ static int dump_task_rlimits(int pid, TaskRlimitsEntry *rls)
>  	return 0;
>  }
>  
> +static int dump_pid_misc(pid_t pid, TaskCoreEntry *tc)
> +{
> +	int ret;
> +
> +	pr_info("dumping /proc/%d/{oom_score_adj,loginuid}\n", pid);
> +
> +	tc->has_loginuid = true;

Can we add loginuid only if it's set? In this case we will able to
remove a default value from a protobuf file.


> +	tc->loginuid = parse_pid_loginuid(pid, &ret);
> +	/*
> +	 * loginuid dumping is critical, as if not correctly
> +	 * restored, you may loss ability to login via SSH to CT
> +	 */
> +	if (ret < 0)
> +		return ret;
> +
> +	tc->oom_score_adj = parse_pid_oom_score_adj(pid, &ret);
> +	/*
> +	 * oom_score_adj dumping is not very critical, as it will affect
> +	 * on victim in OOM situation and one will find dumping error in log
> +	 */
> +	if (ret < 0)
> +		tc->has_oom_score_adj = false;
> +	else
> +		tc->has_oom_score_adj = true;
> +
> +	return 0;
> +}
> +
>  static int dump_filemap(pid_t pid, struct vma_area *vma_area,
>  		const struct cr_imgset *imgset)
>  {
> @@ -702,6 +730,10 @@ static int dump_task_core_all(struct pstree_item *item,
>  	if (ret)
>  		goto err;
>  
> +	ret = dump_pid_misc(pid, core->tc);
> +	if (ret)
> +		goto err;
> +
>  	ret = dump_task_rlimits(pid, core->tc->rlimits);
>  	if (ret)
>  		goto err;
> diff --git a/include/proc_parse.h b/include/proc_parse.h
> index e45d93f..85e7e99 100644
> --- a/include/proc_parse.h
> +++ b/include/proc_parse.h
> @@ -114,6 +114,8 @@ struct vm_area_list;
>  extern bool add_skip_mount(const char *mountpoint);
>  extern struct mount_info *parse_mountinfo(pid_t pid, struct ns_id *nsid, bool for_dump);
>  extern int parse_pid_stat(pid_t pid, struct proc_pid_stat *s);
> +extern unsigned int parse_pid_loginuid(pid_t pid, int *err);
> +extern int parse_pid_oom_score_adj(pid_t pid, int *err);
>  extern int parse_smaps(pid_t pid, struct vm_area_list *vma_area_list);
>  extern int parse_self_maps_lite(struct vm_area_list *vms);
>  extern int parse_pid_status(pid_t pid, struct proc_status_creds *);
> diff --git a/proc_parse.c b/proc_parse.c
> index c479b0f..15b0195 100644
> --- a/proc_parse.c
> +++ b/proc_parse.c
> @@ -724,6 +724,58 @@ err:
>  	return -1;
>  }
>  
> +unsigned int parse_pid_loginuid(pid_t pid, int *err)
> +{
> +	int fd;
> +	ssize_t num;
> +
> +	*err = 0;
> +	fd = open_proc(pid, "loginuid");
> +	if (fd < 0)
> +		goto out;
> +
> +	num = read(fd, buf, 10);
> +	if (num < 0) {
> +		pr_perror("Unable to read /proc/%d/loginuid", pid);
> +		goto close_out;
> +	}
> +	buf[num] = '\0';
> +

	close(fd);

> +	return strtol(buf, NULL, 10);
> +
> +close_out:
> +	close(fd);
> +out:
> +	*err = -1;
> +	return 4294967295; /* unset value */

Maybe we can add a constant for this magic value.

#define INVALID_UID ((uid_t)-1)

> +}
> +
> +int parse_pid_oom_score_adj(pid_t pid, int *err)
> +{
> +	int fd;
> +	ssize_t num;
> +
> +	*err = 0;
> +	fd = open_proc(pid, "oom_score_adj");
> +	if (fd < 0)
> +		goto out;
> +
> +	num = read(fd, buf, 10);
> +	if (num < 0) {
> +		pr_perror("Unable to read /proc/%d/oom_score_adj", pid);
> +		goto close_out;
> +	}
> +	buf[num] = '\0';

	close(fd);

> +
> +	return strtol(buf, NULL, 10);
> +
> +close_out:
> +	close(fd);
> +out:
> +	*err = -1;
> +	return 0;
> +}
> +
>  static int ids_parse(char *str, unsigned int *arr)
>  {
>  	char *end;
> diff --git a/protobuf/core.proto b/protobuf/core.proto
> index 94322c0..4fe604e 100644
> --- a/protobuf/core.proto
> +++ b/protobuf/core.proto
> @@ -38,6 +38,11 @@ message task_core_entry {
>  
>  	optional seccomp_mode		seccomp_mode	= 11;
>  	optional uint32			seccomp_filter	= 12;
> +
> +	optional uint32			loginuid	= 13
> +					[default = 4294967295]; /* not set */
> +
> +	optional int32			oom_score_adj	= 14;
>  }
>  
>  message task_kobj_ids_entry {
> -- 
> 2.6.3
> 
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