From 8d7e6fb0a1db970ac3589f87af0f2a20ef46654b Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 11 Feb 2014 11:52:48 -0500 Subject: [PATCH] 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 Acked-by: Li Zefan --- kernel/cgroup.c | 35 ++++++++++++++++++++++------------- 1 file changed, 22 insertions(+), 13 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 0a178cd1f836..3f204429d108 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -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; -- 2.39.2