driver core: add uid and gid to devtmpfs
Some drivers want to tell userspace what uid and gid should be used for
their device nodes, so allow that information to percolate through the
driver core to userspace in order to make this happen. This means that
some systems (i.e. Android and friends) will not need to even run a
udev-like daemon for their device node manager and can just rely in
devtmpfs fully, reducing their footprint even more.
Signed-off-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/block/genhd.c b/block/genhd.c
index 3c001fba..dfcec43 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1111,7 +1111,8 @@
.name = "block",
};
-static char *block_devnode(struct device *dev, umode_t *mode)
+static char *block_devnode(struct device *dev, umode_t *mode,
+ uid_t *uid, gid_t *gid)
{
struct gendisk *disk = dev_to_disk(dev);
diff --git a/drivers/base/core.c b/drivers/base/core.c
index a7391a3..8a428b5 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -283,15 +283,21 @@
const char *tmp;
const char *name;
umode_t mode = 0;
+ uid_t uid = 0;
+ gid_t gid = 0;
add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
- name = device_get_devnode(dev, &mode, &tmp);
+ name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
if (name) {
add_uevent_var(env, "DEVNAME=%s", name);
- kfree(tmp);
if (mode)
add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
+ if (uid)
+ add_uevent_var(env, "DEVUID=%u", uid);
+ if (gid)
+ add_uevent_var(env, "DEVGID=%u", gid);
+ kfree(tmp);
}
}
@@ -1281,6 +1287,8 @@
* device_get_devnode - path of device node file
* @dev: device
* @mode: returned file access mode
+ * @uid: returned file owner
+ * @gid: returned file group
* @tmp: possibly allocated string
*
* Return the relative path of a possible device node.
@@ -1289,7 +1297,8 @@
* freed by the caller.
*/
const char *device_get_devnode(struct device *dev,
- umode_t *mode, const char **tmp)
+ umode_t *mode, uid_t *uid, gid_t *gid,
+ const char **tmp)
{
char *s;
@@ -1297,7 +1306,7 @@
/* the device type may provide a specific name */
if (dev->type && dev->type->devnode)
- *tmp = dev->type->devnode(dev, mode);
+ *tmp = dev->type->devnode(dev, mode, uid, gid);
if (*tmp)
return *tmp;
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 01fc5b0..fda5256 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -41,6 +41,8 @@
int err;
const char *name;
umode_t mode; /* 0 => delete */
+ uid_t uid;
+ gid_t gid;
struct device *dev;
} *requests;
@@ -85,7 +87,9 @@
return 0;
req.mode = 0;
- req.name = device_get_devnode(dev, &req.mode, &tmp);
+ req.uid = 0;
+ req.gid = 0;
+ req.name = device_get_devnode(dev, &req.mode, &req.uid, &req.gid, &tmp);
if (!req.name)
return -ENOMEM;
@@ -121,7 +125,7 @@
if (!thread)
return 0;
- req.name = device_get_devnode(dev, NULL, &tmp);
+ req.name = device_get_devnode(dev, NULL, NULL, NULL, &tmp);
if (!req.name)
return -ENOMEM;
@@ -187,7 +191,8 @@
return err;
}
-static int handle_create(const char *nodename, umode_t mode, struct device *dev)
+static int handle_create(const char *nodename, umode_t mode, uid_t uid,
+ gid_t gid, struct device *dev)
{
struct dentry *dentry;
struct path path;
@@ -201,14 +206,14 @@
if (IS_ERR(dentry))
return PTR_ERR(dentry);
- err = vfs_mknod(path.dentry->d_inode,
- dentry, mode, dev->devt);
+ err = vfs_mknod(path.dentry->d_inode, dentry, mode, dev->devt);
if (!err) {
struct iattr newattrs;
- /* fixup possibly umasked mode */
newattrs.ia_mode = mode;
- newattrs.ia_valid = ATTR_MODE;
+ newattrs.ia_uid = uid;
+ newattrs.ia_gid = gid;
+ newattrs.ia_valid = ATTR_MODE|ATTR_UID|ATTR_GID;
mutex_lock(&dentry->d_inode->i_mutex);
notify_change(dentry, &newattrs);
mutex_unlock(&dentry->d_inode->i_mutex);
@@ -358,10 +363,11 @@
static DECLARE_COMPLETION(setup_done);
-static int handle(const char *name, umode_t mode, struct device *dev)
+static int handle(const char *name, umode_t mode, uid_t uid, gid_t gid,
+ struct device *dev)
{
if (mode)
- return handle_create(name, mode, dev);
+ return handle_create(name, mode, uid, gid, dev);
else
return handle_remove(name, dev);
}
@@ -387,7 +393,8 @@
spin_unlock(&req_lock);
while (req) {
struct req *next = req->next;
- req->err = handle(req->name, req->mode, req->dev);
+ req->err = handle(req->name, req->mode,
+ req->uid, req->gid, req->dev);
complete(&req->done);
req = next;
}
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index f81b925..1700283 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -317,7 +317,8 @@
#endif /* CONFIG_PM */
-static char *usb_devnode(struct device *dev, umode_t *mode)
+static char *usb_devnode(struct device *dev,
+ umode_t *mode, uid_t *uid, gid_t *gid)
{
struct usb_device *usb_dev;
diff --git a/include/linux/device.h b/include/linux/device.h
index 4a7c4a8..851b85c 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -25,6 +25,7 @@
#include <linux/pm.h>
#include <linux/atomic.h>
#include <linux/ratelimit.h>
+#include <linux/uidgid.h>
#include <asm/device.h>
struct device;
@@ -465,7 +466,8 @@
const char *name;
const struct attribute_group **groups;
int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
- char *(*devnode)(struct device *dev, umode_t *mode);
+ char *(*devnode)(struct device *dev, umode_t *mode,
+ uid_t *uid, gid_t *gid);
void (*release)(struct device *dev);
const struct dev_pm_ops *pm;
@@ -843,7 +845,8 @@
extern int device_move(struct device *dev, struct device *new_parent,
enum dpm_order dpm_order);
extern const char *device_get_devnode(struct device *dev,
- umode_t *mode, const char **tmp);
+ umode_t *mode, uid_t *uid, gid_t *gid,
+ const char **tmp);
extern void *dev_get_drvdata(const struct device *dev);
extern int dev_set_drvdata(struct device *dev, void *data);