According to the sysfs header file:
"The returned value will replace static permissions defined in
struct attribute or struct bin_attribute."
but this isn't the case, as is_visible is only called on struct attribute
only. This patch introduces a new is_bin_visible() function to implement
the same functionality for binary attributes, and updates documentation
accordingly.
Signed-off-by: Emilio López <emilio.lopez@xxxxxxxxxxxxxxx>
---
Changes from v1:
- Don't overload is_visible, introduce is_bin_visible instead as
discussed on the list.
fs/sysfs/group.c | 17 +++++++++++++++--
include/linux/sysfs.h | 18 ++++++++++++++----
2 files changed, 29 insertions(+), 6 deletions(-)
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index 39a0199..51b56e6 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -73,13 +73,26 @@ static int create_files(struct kernfs_node *parent, struct kobject *kobj,
}
if (grp->bin_attrs) {
- for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
+ for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
+ umode_t mode = (*bin_attr)->attr.mode;
+
if (update)
kernfs_remove_by_name(parent,
(*bin_attr)->attr.name);
+ if (grp->is_bin_visible) {
+ mode = grp->is_bin_visible(kobj, *bin_attr, i);
+ if (!mode)
+ continue;
+ }
+
+ WARN(mode & ~(SYSFS_PREALLOC | 0664),
+ "Attribute %s: Invalid permissions 0%o\n",
+ (*bin_attr)->attr.name, mode);
+
+ mode &= SYSFS_PREALLOC | 0664;
error = sysfs_add_file_mode_ns(parent,
&(*bin_attr)->attr, true,
- (*bin_attr)->attr.mode, NULL);
+ mode, NULL);
if (error)
break;
}
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 9f65758..2f66050 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -64,10 +64,18 @@ do { \
* a new subdirectory with this name.
* @is_visible: Optional: Function to return permissions associated with an
* attribute of the group. Will be called repeatedly for each
- * attribute in the group. Only read/write permissions as well as
- * SYSFS_PREALLOC are accepted. Must return 0 if an attribute is
- * not visible. The returned value will replace static permissions
- * defined in struct attribute or struct bin_attribute.
+ * non-binary attribute in the group. Only read/write
+ * permissions as well as SYSFS_PREALLOC are accepted. Must
+ * return 0 if an attribute is not visible. The returned value
+ * will replace static permissions defined in struct attribute.
+ * @is_bin_visible:
+ * Optional: Function to return permissions associated with a
+ * binary attribute of the group. Will be called repeatedly
+ * for each binary attribute in the group. Only read/write
+ * permissions as well as SYSFS_PREALLOC are accepted. Must
+ * return 0 if a binary attribute is not visible. The returned
+ * value will replace static permissions defined in
+ * struct bin_attribute.
* @attrs: Pointer to NULL terminated list of attributes.
* @bin_attrs: Pointer to NULL terminated list of binary attributes.
* Either attrs or bin_attrs or both must be provided.
@@ -76,6 +84,8 @@ struct attribute_group {
const char *name;
umode_t (*is_visible)(struct kobject *,
struct attribute *, int);
+ umode_t (*is_bin_visible)(struct kobject *,
+ struct bin_attribute *, int);
struct attribute **attrs;
struct bin_attribute **bin_attrs;
};
--
2.1.4
--
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