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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: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
This commit is contained in:
Tejun Heo 2014-02-11 11:52:48 -05:00
parent d427dfeb12
commit 8d7e6fb0a1
1 changed files with 22 additions and 13 deletions
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35
kernel/cgroup.c
View File

@ -67,6 +67,9 @@
*/ */
#define CGROUP_PIDLIST_DESTROY_DELAY HZ #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 * cgroup_tree_mutex nests above cgroup_mutex and protects cftypes, file
* creation/removal and hierarchy changing operations including cgroup * 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; 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; 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) if (!name)
return NULL; return NULL;
strcpy(name->name, dentry->d_name.name); strcpy(name->name, name_str);
return name; 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) static void cgroup_free_fn(struct work_struct *work)
{ {
struct cgroup *cgrp = container_of(work, struct cgroup, destroy_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)) if (cgroup_sane_behavior(cgrp))
return -EPERM; return -EPERM;
name = cgroup_alloc_name(new_dentry); name = cgroup_alloc_name(new_dentry->d_name.name);
if (!name) if (!name)
return -ENOMEM; return -ENOMEM;
@ -2613,14 +2628,7 @@ static int cgroup_add_file(struct cgroup *cgrp, struct cftype *cft)
struct cfent *cfe; struct cfent *cfe;
int error; int error;
umode_t mode; umode_t mode;
char name[MAX_CGROUP_TYPE_NAMELEN + MAX_CFTYPE_NAME + 2] = { 0 }; char name[CGROUP_FILE_NAME_MAX];
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);
BUG_ON(!mutex_is_locked(&dir->d_inode->i_mutex)); 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) if (!cfe)
return -ENOMEM; return -ENOMEM;
cgroup_file_name(cgrp, cft, name);
dentry = lookup_one_len(name, dir, strlen(name)); dentry = lookup_one_len(name, dir, strlen(name));
if (IS_ERR(dentry)) { if (IS_ERR(dentry)) {
error = PTR_ERR(dentry); error = PTR_ERR(dentry);
@ -4135,7 +4144,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
if (!cgrp) if (!cgrp)
return -ENOMEM; return -ENOMEM;
name = cgroup_alloc_name(dentry); name = cgroup_alloc_name(dentry->d_name.name);
if (!name) { if (!name) {
err = -ENOMEM; err = -ENOMEM;
goto err_free_cgrp; goto err_free_cgrp;