[CRIU] [PATCH] cg: Use relative paths in cgroup dirs image

[Tycho Andersen]

On Wed, Aug 13, 2014 at 01:34:22PM +0400, Pavel Emelyanov wrote:
> Before the patch cg tree section from cgroup00 test looked like this
> 
> {
> 	cnames: "name=zdtmtst"
> 	dirs: 	{
> 		path: "/subcg"
> 		children: 		{
> 			path: "/subcg/subsubcg"
> 			children: <empty>
> 			properties: <empty>
> 		}
> 
> 		properties: <empty>
> 	}
> 
> }
> 
> this /subsg in the children is excessive. Turn this into directory names.
> Now the section looks like
> 
> {
> 	cnames: "name=zdtmtst"
> 	dirs: 	{
> 		dir_name: "subcg"
> 		children: 		{
> 			dir_name: "subsubcg"
> 			children: <empty>
> 			properties: <empty>
> 		}
> 
> 		properties: <empty>
> 	}
> 
> }
> 
> Signed-off-by: Pavel Emelyanov <xemul at parallels.com>

Acked-by: Tycho Andersen <tycho.andersen at canonical.com>

> ---
>  cgroup.c              | 19 +++++++++----------
>  protobuf/cgroup.proto |  2 +-
>  2 files changed, 10 insertions(+), 11 deletions(-)
> 
> diff --git a/cgroup.c b/cgroup.c
> index 8308413..1f38c4d 100644
> --- a/cgroup.c
> +++ b/cgroup.c
> @@ -641,7 +641,7 @@ error:
>  	return -1;
>  }
>  
> -static int dump_cg_dirs(struct list_head *dirs, size_t n_dirs, CgroupDirEntry ***ents)
> +static int dump_cg_dirs(struct list_head *dirs, size_t n_dirs, CgroupDirEntry ***ents, int poff)
>  {
>  	struct cgroup_dir *cur;
>  	CgroupDirEntry *cde;
> @@ -657,12 +657,10 @@ static int dump_cg_dirs(struct list_head *dirs, size_t n_dirs, CgroupDirEntry **
>  
>  	list_for_each_entry(cur, dirs, siblings) {
>  		cgroup_dir_entry__init(cde);
> -
> -		cde->path = cur->path;
> -
> +		cde->dir_name = cur->path + poff + 1 /* leading / */;
>  		cde->n_children = cur->n_children;
>  		if (cur->n_children > 0)
> -			if (dump_cg_dirs(&cur->children, cur->n_children, &cde->children) < 0) {
> +			if (dump_cg_dirs(&cur->children, cur->n_children, &cde->children, strlen(cur->path)) < 0) {
>  				xfree(*ents);
>  				return -1;
>  			}
> @@ -704,7 +702,7 @@ static int dump_controllers(CgroupEntry *cg)
>  		ce->n_cnames = cur->n_controllers;
>  		ce->n_dirs = cur->n_heads;
>  		if (ce->n_dirs > 0)
> -			if (dump_cg_dirs(&cur->heads, cur->n_heads, &ce->dirs) < 0) {
> +			if (dump_cg_dirs(&cur->heads, cur->n_heads, &ce->dirs, 0) < 0) {
>  				xfree(cg->controllers);
>  				return -1;
>  			}
> @@ -930,7 +928,7 @@ void fini_cgroup(void)
>  }
>  
>  static int restore_cgroup_prop(const CgroupPropEntry * cg_prop_entry_p,
> -			       char *path, int off, const char *dir)
> +			       char *path, int off)
>  {
>  	FILE *f;
>  	int cg;
> @@ -940,7 +938,7 @@ static int restore_cgroup_prop(const CgroupPropEntry * cg_prop_entry_p,
>  		return -1;
>  	}
>  
> -	if (snprintf(path + off, PATH_MAX - off, "/%s/%s", dir, cg_prop_entry_p->name) >= PATH_MAX) {
> +	if (snprintf(path + off, PATH_MAX - off, "/%s", cg_prop_entry_p->name) >= PATH_MAX) {
>  		pr_err("snprintf output was truncated for %s\n", cg_prop_entry_p->name);
>  		return -1;
>  	}
> @@ -975,6 +973,7 @@ static int prepare_cgroup_dir_properties(char *path, int off, CgroupDirEntry **e
>  	for (i = 0; i < n_ents; i++) {
>  		CgroupDirEntry *e = ents[i];
>  
> +		off += sprintf(path + off, "/%s", e->dir_name);
>  		/*
>  		 * Check to see if we made e->properties NULL during restore
>  		 * because directory already existed and as such we don't want to
> @@ -982,7 +981,7 @@ static int prepare_cgroup_dir_properties(char *path, int off, CgroupDirEntry **e
>  		 */
>  		if (e->properties) {
>  			for (j = 0; j < e->n_properties; ++j) {
> -				if (restore_cgroup_prop(e->properties[j], path, off, e->path) < 0)
> +				if (restore_cgroup_prop(e->properties[j], path, off) < 0)
>  					return -1;
>  			}
>  		}
> @@ -1023,7 +1022,7 @@ static int prepare_cgroup_dirs(char *paux, size_t off, CgroupDirEntry **ents, si
>  	for (i = 0; i < n_ents; i++) {
>  		e = ents[i];
>  
> -		sprintf(paux + off, "/%s", e->path);
> +		off += sprintf(paux + off, "/%s", e->dir_name);
>  
>  		/*
>  		 * Checking to see if file already exists. If not, create it. If
> diff --git a/protobuf/cgroup.proto b/protobuf/cgroup.proto
> index fcd5834..2084388 100644
> --- a/protobuf/cgroup.proto
> +++ b/protobuf/cgroup.proto
> @@ -4,7 +4,7 @@ message cgroup_prop_entry {
>  }
>  
>  message cgroup_dir_entry {
> -	required string 		path		= 1;
> +	required string 		dir_name	= 1;
>  	repeated cgroup_dir_entry	children 	= 2;
>  	repeated cgroup_prop_entry	properties	= 3;
>  }
> -- 
> 1.8.4.2
> 
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