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Commit 8d7e6fb0 authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: update cgroup name handling 



Straightforward updates to cgroup name handling in preparation of
kernfs conversion.

* cgroup_alloc_name() is updated to take const char * isntead of
  dentry * for name source.

* cgroup name formatting is separated out into cgroup_file_name().
  While at it, buffer length protection is added.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
parent d427dfeb

kernel/cgroup.c

+22 −13
Original line number Diff line number Diff line
@@ -67,6 +67,9 @@ 
 */

#define CGROUP_PIDLIST_DESTROY_DELAY	HZ



#define CGROUP_FILE_NAME_MAX		(MAX_CGROUP_TYPE_NAMELEN +	\

					 MAX_CFTYPE_NAME + 2)



/*

 * cgroup_tree_mutex nests above cgroup_mutex and protects cftypes, file

 * creation/removal and hierarchy changing operations including cgroup
@@ -799,17 +802,29 @@ static struct inode *cgroup_new_inode(umode_t mode, struct super_block *sb) 
	return inode;

}



static struct cgroup_name *cgroup_alloc_name(struct dentry *dentry)

static struct cgroup_name *cgroup_alloc_name(const char *name_str)

{

	struct cgroup_name *name;



	name = kmalloc(sizeof(*name) + dentry->d_name.len + 1, GFP_KERNEL);

	name = kmalloc(sizeof(*name) + strlen(name_str) + 1, GFP_KERNEL);

	if (!name)

		return NULL;

	strcpy(name->name, dentry->d_name.name);

	strcpy(name->name, name_str);

	return name;

}



static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,

			      char *buf)

{

	if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&

	    !(cgrp->root->flags & CGRP_ROOT_NOPREFIX))

		snprintf(buf, CGROUP_FILE_NAME_MAX, "%s.%s",

			 cft->ss->name, cft->name);

	else

		strncpy(buf, cft->name, CGROUP_FILE_NAME_MAX);

	return buf;

}



static void cgroup_free_fn(struct work_struct *work)

{

	struct cgroup *cgrp = container_of(work, struct cgroup, destroy_work);
@@ -2437,7 +2452,7 @@ static int cgroup_rename(struct inode *old_dir, struct dentry *old_dentry, 
	if (cgroup_sane_behavior(cgrp))

		return -EPERM;



	name = cgroup_alloc_name(new_dentry);

	name = cgroup_alloc_name(new_dentry->d_name.name);

	if (!name)

		return -ENOMEM;
@@ -2613,14 +2628,7 @@ static int cgroup_add_file(struct cgroup *cgrp, struct cftype *cft) 
	struct cfent *cfe;

	int error;

	umode_t mode;

	char name[MAX_CGROUP_TYPE_NAMELEN + MAX_CFTYPE_NAME + 2] = { 0 };



	if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&

	    !(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) {

		strcpy(name, cft->ss->name);

		strcat(name, ".");

	}

	strcat(name, cft->name);

	char name[CGROUP_FILE_NAME_MAX];



	BUG_ON(!mutex_is_locked(&dir->d_inode->i_mutex));
@@ -2628,6 +2636,7 @@ static int cgroup_add_file(struct cgroup *cgrp, struct cftype *cft) 
	if (!cfe)

		return -ENOMEM;



	cgroup_file_name(cgrp, cft, name);

	dentry = lookup_one_len(name, dir, strlen(name));

	if (IS_ERR(dentry)) {

		error = PTR_ERR(dentry);
@@ -4135,7 +4144,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, 
	if (!cgrp)

		return -ENOMEM;



	name = cgroup_alloc_name(dentry);

	name = cgroup_alloc_name(dentry->d_name.name);

	if (!name) {

		err = -ENOMEM;

		goto err_free_cgrp;