[PATCH] sysfs: add sysfs_chmod_file()

sysfs: allow changing the permissions for already created attributes

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 352f966a1174681f0c1e6a5801942b16d8df7d40..da25aeb0e062093c242778d38b95bafe2a168c81 100644 (file)
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -427,6 +427,41 @@ int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)
 }
 
 
+/**
+ * sysfs_chmod_file - update the modified mode value on an object attribute.
+ * @kobj: object we're acting for.
+ * @attr: attribute descriptor.
+ * @mode: file permissions.
+ *
+ */
+int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
+{
+       struct dentry *dir = kobj->dentry;
+       struct dentry *victim;
+       struct sysfs_dirent *sd;
+       umode_t umode = (mode & S_IALLUGO) | S_IFREG;
+       int res = -ENOENT;
+
+       down(&dir->d_inode->i_sem);
+       victim = sysfs_get_dentry(dir, attr->name);
+       if (!IS_ERR(victim)) {
+               if (victim->d_inode &&
+                   (victim->d_parent->d_inode == dir->d_inode)) {
+                       sd = victim->d_fsdata;
+                       attr->mode = mode;
+                       sd->s_mode = umode;
+                       victim->d_inode->i_mode = umode;
+                       dput(victim);
+                       res = 0;
+               }
+       }
+       up(&dir->d_inode->i_sem);
+
+       return res;
+}
+EXPORT_SYMBOL_GPL(sysfs_chmod_file);
+
+
 /**
  *     sysfs_remove_file - remove an object attribute.
  *     @kobj:  object we're acting for.

diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 6f502ff7902a03bf880b2d4155ca146ae6d4654a..38b58b30814a304ddcd803ea10595fb35880a41c 100644 (file)
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -99,6 +99,9 @@ sysfs_create_file(struct kobject *, const struct attribute *);
 extern int
 sysfs_update_file(struct kobject *, const struct attribute *);
 
+extern int
+sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode);
+
 extern void
 sysfs_remove_file(struct kobject *, const struct attribute *);
 
@@ -140,6 +143,10 @@ static inline int sysfs_update_file(struct kobject * k, const struct attribute *
 {
        return 0;
 }
+static inline int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
+{
+       return 0;
+}
 
 static inline void sysfs_remove_file(struct kobject * k, const struct attribute * a)
 {