diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/xattr.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/fs/xattr.c b/fs/xattr.c index f060663ab70c..851808c92b30 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -166,6 +166,64 @@ out_noalloc: } EXPORT_SYMBOL_GPL(xattr_getsecurity); +/* + * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr + * + * Allocate memory, if not already allocated, or re-allocate correct size, + * before retrieving the extended attribute. + * + * Returns the result of alloc, if failed, or the getxattr operation. + */ +ssize_t +vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value, + size_t xattr_size, gfp_t flags) +{ + struct inode *inode = dentry->d_inode; + char *value = *xattr_value; + int error; + + error = xattr_permission(inode, name, MAY_READ); + if (error) + return error; + + if (!inode->i_op->getxattr) + return -EOPNOTSUPP; + + error = inode->i_op->getxattr(dentry, name, NULL, 0); + if (error < 0) + return error; + + if (!value || (error > xattr_size)) { + value = krealloc(*xattr_value, error + 1, flags); + if (!value) + return -ENOMEM; + memset(value, 0, error + 1); + } + + error = inode->i_op->getxattr(dentry, name, value, error); + *xattr_value = value; + return error; +} + +/* Compare an extended attribute value with the given value */ +int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name, + const char *value, size_t size, gfp_t flags) +{ + char *xattr_value = NULL; + int rc; + + rc = vfs_getxattr_alloc(dentry, xattr_name, &xattr_value, 0, flags); + if (rc < 0) + return rc; + + if ((rc != size) || (memcmp(xattr_value, value, rc) != 0)) + rc = -EINVAL; + else + rc = 0; + kfree(xattr_value); + return rc; +} + ssize_t vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) { |