UHID_CREATE and UHID_DESTROY are used to create and destroy a device on an
open uhid char-device. Internally, we allocate and register an HID device
with the HID core and immediately start the device. From now on events may
be received or sent to the device.
The UHID_CREATE event has a payload similar to the data used by
Bluetooth-HIDP when creating a new connection.
Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxxxxxxx>
---
drivers/hid/uhid.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/uhid.h | 21 +++++++-
2 files changed, 164 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index 31e8379..61ee7cc 100644
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c
@@ -29,6 +29,11 @@
struct uhid_device {
struct mutex devlock;
+ bool running;
+
+ __u8 *rd_data;
+ uint rd_size;
+
struct hid_device *hid;
struct uhid_event input_buf;
@@ -75,6 +80,136 @@ static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
return 0;
}
+static int uhid_hid_start(struct hid_device *hid)
+{
+ return 0;
+}
+
+static void uhid_hid_stop(struct hid_device *hid)
+{
+}
+
+static int uhid_hid_open(struct hid_device *hid)
+{
+ return 0;
+}
+
+static void uhid_hid_close(struct hid_device *hid)
+{
+}
+
+static int uhid_hid_input(struct input_dev *input, unsigned int type,
+ unsigned int code, int value)
+{
+ return 0;
+}
+
+static int uhid_hid_parse(struct hid_device *hid)
+{
+ return 0;
+}
+
+static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
+ __u8 *buf, size_t count, unsigned char rtype)
+{
+ return 0;
+}
+
+static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
+ unsigned char report_type)
+{
+ return 0;
+}
+
+static struct hid_ll_driver uhid_hid_driver = {
+ .start = uhid_hid_start,
+ .stop = uhid_hid_stop,
+ .open = uhid_hid_open,
+ .close = uhid_hid_close,
+ .hidinput_input_event = uhid_hid_input,
+ .parse = uhid_hid_parse,
+};
+
+static int uhid_dev_create(struct uhid_device *uhid,
+ const struct uhid_event *ev)
+{
+ struct hid_device *hid;
+ int ret;
+
+ if (uhid->running)
+ return -EALREADY;
+
+ uhid->rd_size = ev->u.create.rd_size;
+ if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
+ return -EINVAL;
+
+ uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
+ if (!uhid->rd_data)
+ return -ENOMEM;
+
+ if (copy_from_user(uhid->rd_data, ev->u.create.rd_data,
+ uhid->rd_size)) {
+ ret = -EFAULT;
+ goto err_free;
+ }
+
+ hid = hid_allocate_device();
+ if (IS_ERR(hid)) {
+ ret = PTR_ERR(hid);
+ goto err_free;
+ }
+
+ strncpy(hid->name, ev->u.create.name, 127);
+ hid->name[127] = 0;
+ strncpy(hid->phys, ev->u.create.phys, 63);
+ hid->phys[63] = 0;
+ strncpy(hid->uniq, ev->u.create.uniq, 63);
+ hid->uniq[63] = 0;
+
+ hid->ll_driver = &uhid_hid_driver;
+ hid->hid_get_raw_report = uhid_hid_get_raw;
+ hid->hid_output_raw_report = uhid_hid_output_raw;
+ hid->bus = ev->u.create.bus;
+ hid->vendor = ev->u.create.vendor;
+ hid->product = ev->u.create.product;
+ hid->version = ev->u.create.version;
+ hid->country = ev->u.create.country;
+ hid->driver_data = uhid;
+ hid->dev.parent = uhid_misc.this_device;
+
+ uhid->hid = hid;
+ uhid->running = true;
+
+ ret = hid_add_device(hid);
+ if (ret) {
+ hid_err(hid, "Cannot register HID device\n");
+ goto err_hid;
+ }
+
+ return 0;
+
+err_hid:
+ hid_destroy_device(hid);
+ uhid->hid = NULL;
+ uhid->running = false;
+err_free:
+ kfree(uhid->rd_data);
+ return ret;
+}
+
+static int uhid_dev_destroy(struct uhid_device *uhid)
+{
+ if (!uhid->running)
+ return -EINVAL;
+
+ uhid->running = false;
+
+ hid_destroy_device(uhid->hid);
+ kfree(uhid->rd_data);
+
+ return 0;
+}
+
static int uhid_char_open(struct inode *inode, struct file *file)
{
struct uhid_device *uhid;
@@ -86,6 +221,7 @@ static int uhid_char_open(struct inode *inode, struct file *file)
mutex_init(&uhid->devlock);
spin_lock_init(&uhid->qlock);
init_waitqueue_head(&uhid->waitq);
+ uhid->running = false;
file->private_data = uhid;
nonseekable_open(inode, file);
@@ -98,6 +234,8 @@ static int uhid_char_release(struct inode *inode, struct file *file)
struct uhid_device *uhid = file->private_data;
unsigned int i;
+ uhid_dev_destroy(uhid);
+
for (i = 0; i < UHID_BUFSIZE; ++i)
kfree(uhid->outq[i]);
@@ -177,6 +315,12 @@ static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
}
switch (uhid->input_buf.type) {
+ case UHID_CREATE:
+ ret = uhid_dev_create(uhid, &uhid->input_buf);
+ break;
+ case UHID_DESTROY:
+ ret = uhid_dev_destroy(uhid);
+ break;
default:
ret = -EOPNOTSUPP;
}
diff --git a/include/linux/uhid.h b/include/linux/uhid.h
index 16b786a..8a493e6 100644
--- a/include/linux/uhid.h
+++ b/include/linux/uhid.h
@@ -23,11 +23,30 @@
#include <linux/types.h>
enum uhid_event_type {
- UHID_DUMMY,
+ UHID_CREATE,
+ UHID_DESTROY,
};
+struct uhid_create_req {
+ __u8 name[128];
+ __u8 phys[64];
+ __u8 uniq[64];
+ __u8 __user *rd_data;
+ __u16 rd_size;
+
+ __u16 bus;
+ __u32 vendor;
+ __u32 product;
+ __u32 version;
+ __u32 country;
+} __attribute__((__packed__));
+
struct uhid_event {
__u32 type;
+
+ union {
+ struct uhid_create_req create;
+ } u;
} __attribute__((__packed__));
#endif /* __UHID_H_ */
--
1.7.10.4
--
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