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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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/* */
#include <linux/atomic.h>#include <linux/compat.h>#include <linux/cred.h>#include <linux/device.h>#include <linux/fs.h>#include <linux/hid.h>#include <linux/input.h>#include <linux/miscdevice.h>#include <linux/module.h>#include <linux/mutex.h>#include <linux/poll.h>#include <linux/sched.h>#include <linux/spinlock.h>#include <linux/uhid.h>#include <linux/wait.h>
#define UHID_NAME "uhid"#define UHID_BUFSIZE 32
struct uhid_device { struct mutex devlock;
/* This flag tracks whether the HID device is usable for commands from * userspace. The flag is already set before hid_add_device(), which * runs in workqueue context, to allow hid_add_device() to communicate * with userspace. * However, if hid_add_device() fails, the flag is cleared without * holding devlock. * We guarantee that if @running changes from true to false while you're * holding @devlock, it's still fine to access @hid. */ bool running;
__u8 *rd_data; uint rd_size;
/* When this is NULL, userspace may use UHID_CREATE/UHID_CREATE2. */ struct hid_device *hid; struct uhid_event input_buf;
wait_queue_head_t waitq; spinlock_t qlock; __u8 head; __u8 tail; struct uhid_event *outq[UHID_BUFSIZE];
/* blocking GET_REPORT support; state changes protected by qlock */ struct mutex report_lock; wait_queue_head_t report_wait; bool report_running; u32 report_id; u32 report_type; struct uhid_event report_buf; struct work_struct worker;};
static struct miscdevice uhid_misc;
static void uhid_device_add_worker(struct work_struct *work){ struct uhid_device *uhid = container_of(work, struct uhid_device, worker); int ret;
ret = hid_add_device(uhid->hid); if (ret) { hid_err(uhid->hid, "Cannot register HID device: error %d\n", ret);
/* We used to call hid_destroy_device() here, but that's really * messy to get right because we have to coordinate with * concurrent writes from userspace that might be in the middle * of using uhid->hid. * Just leave uhid->hid as-is for now, and clean it up when * userspace tries to close or reinitialize the uhid instance. * * However, we do have to clear the ->running flag and do a * wakeup to make sure userspace knows that the device is gone. */ WRITE_ONCE(uhid->running, false); wake_up_interruptible(&uhid->report_wait); }}
static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev){ __u8 newhead;
newhead = (uhid->head + 1) % UHID_BUFSIZE;
if (newhead != uhid->tail) { uhid->outq[uhid->head] = ev; uhid->head = newhead; wake_up_interruptible(&uhid->waitq); } else { hid_warn(uhid->hid, "Output queue is full\n"); kfree(ev); }}
static int uhid_queue_event(struct uhid_device *uhid, __u32 event){ unsigned long flags; struct uhid_event *ev;
ev = kzalloc_obj(*ev); if (!ev) return -ENOMEM;
ev->type = event;
spin_lock_irqsave(&uhid->qlock, flags); uhid_queue(uhid, ev); spin_unlock_irqrestore(&uhid->qlock, flags);
return 0;}
static int uhid_hid_start(struct hid_device *hid){ struct uhid_device *uhid = hid->driver_data; struct uhid_event *ev; unsigned long flags;
ev = kzalloc_obj(*ev); if (!ev) return -ENOMEM;
ev->type = UHID_START;
if (hid->report_enum[HID_FEATURE_REPORT].numbered) ev->u.start.dev_flags |= UHID_DEV_NUMBERED_FEATURE_REPORTS; if (hid->report_enum[HID_OUTPUT_REPORT].numbered) ev->u.start.dev_flags |= UHID_DEV_NUMBERED_OUTPUT_REPORTS; if (hid->report_enum[HID_INPUT_REPORT].numbered) ev->u.start.dev_flags |= UHID_DEV_NUMBERED_INPUT_REPORTS;
spin_lock_irqsave(&uhid->qlock, flags); uhid_queue(uhid, ev); spin_unlock_irqrestore(&uhid->qlock, flags);
return 0;}
static void uhid_hid_stop(struct hid_device *hid){ struct uhid_device *uhid = hid->driver_data;
hid->claimed = 0; uhid_queue_event(uhid, UHID_STOP);}
static int uhid_hid_open(struct hid_device *hid){ struct uhid_device *uhid = hid->driver_data;
return uhid_queue_event(uhid, UHID_OPEN);}
static void uhid_hid_close(struct hid_device *hid){ struct uhid_device *uhid = hid->driver_data;
uhid_queue_event(uhid, UHID_CLOSE);}
static int uhid_hid_parse(struct hid_device *hid){ struct uhid_device *uhid = hid->driver_data;
return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);}
/* must be called with report_lock held */static int __uhid_report_queue_and_wait(struct uhid_device *uhid, struct uhid_event *ev, __u32 *report_id){ unsigned long flags; int ret;
spin_lock_irqsave(&uhid->qlock, flags); *report_id = ++uhid->report_id; uhid->report_type = ev->type + 1; uhid->report_running = true; uhid_queue(uhid, ev); spin_unlock_irqrestore(&uhid->qlock, flags);
ret = wait_event_interruptible_timeout(uhid->report_wait, !uhid->report_running || !READ_ONCE(uhid->running), 5 * HZ); if (!ret || !READ_ONCE(uhid->running) || uhid->report_running) ret = -EIO; else if (ret < 0) ret = -ERESTARTSYS; else ret = 0;
uhid->report_running = false;
return ret;}
static void uhid_report_wake_up(struct uhid_device *uhid, u32 id, const struct uhid_event *ev){ unsigned long flags;
spin_lock_irqsave(&uhid->qlock, flags);
/* id for old report; drop it silently */ if (uhid->report_type != ev->type || uhid->report_id != id) goto unlock; if (!uhid->report_running) goto unlock;
memcpy(&uhid->report_buf, ev, sizeof(*ev)); uhid->report_running = false; wake_up_interruptible(&uhid->report_wait);
unlock: spin_unlock_irqrestore(&uhid->qlock, flags);}
static int uhid_hid_get_report(struct hid_device *hid, unsigned char rnum, u8 *buf, size_t count, u8 rtype){ struct uhid_device *uhid = hid->driver_data; struct uhid_get_report_reply_req *req; struct uhid_event *ev; int ret;
if (!READ_ONCE(uhid->running)) return -EIO;
ev = kzalloc_obj(*ev); if (!ev) return -ENOMEM;
ev->type = UHID_GET_REPORT; ev->u.get_report.rnum = rnum; ev->u.get_report.rtype = rtype;
ret = mutex_lock_interruptible(&uhid->report_lock); if (ret) { kfree(ev); return ret; }
/* this _always_ takes ownership of @ev */ ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.get_report.id); if (ret) goto unlock;
req = &uhid->report_buf.u.get_report_reply; if (req->err) { ret = -EIO; } else { ret = min3(count, (size_t)req->size, (size_t)UHID_DATA_MAX); memcpy(buf, req->data, ret); }
unlock: mutex_unlock(&uhid->report_lock); return ret;}
static int uhid_hid_set_report(struct hid_device *hid, unsigned char rnum, const u8 *buf, size_t count, u8 rtype){ struct uhid_device *uhid = hid->driver_data; struct uhid_event *ev; int ret;
if (!READ_ONCE(uhid->running) || count > UHID_DATA_MAX) return -EIO;
ev = kzalloc_obj(*ev); if (!ev) return -ENOMEM;
ev->type = UHID_SET_REPORT; ev->u.set_report.rnum = rnum; ev->u.set_report.rtype = rtype; ev->u.set_report.size = count; memcpy(ev->u.set_report.data, buf, count);
ret = mutex_lock_interruptible(&uhid->report_lock); if (ret) { kfree(ev); return ret; }
/* this _always_ takes ownership of @ev */ ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.set_report.id); if (ret) goto unlock;
if (uhid->report_buf.u.set_report_reply.err) ret = -EIO; else ret = count;
unlock: mutex_unlock(&uhid->report_lock); return ret;}
static int uhid_hid_raw_request(struct hid_device *hid, unsigned char reportnum, __u8 *buf, size_t len, unsigned char rtype, int reqtype){ u8 u_rtype;
switch (rtype) { case HID_FEATURE_REPORT: u_rtype = UHID_FEATURE_REPORT; break; case HID_OUTPUT_REPORT: u_rtype = UHID_OUTPUT_REPORT; break; case HID_INPUT_REPORT: u_rtype = UHID_INPUT_REPORT; break; default: return -EINVAL; }
switch (reqtype) { case HID_REQ_GET_REPORT: return uhid_hid_get_report(hid, reportnum, buf, len, u_rtype); case HID_REQ_SET_REPORT: return uhid_hid_set_report(hid, reportnum, buf, len, u_rtype); default: return -EIO; }}
static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count, unsigned char report_type){ struct uhid_device *uhid = hid->driver_data; __u8 rtype; unsigned long flags; struct uhid_event *ev;
switch (report_type) { case HID_FEATURE_REPORT: rtype = UHID_FEATURE_REPORT; break; case HID_OUTPUT_REPORT: rtype = UHID_OUTPUT_REPORT; break; default: return -EINVAL; }
if (count < 1 || count > UHID_DATA_MAX) return -EINVAL;
ev = kzalloc_obj(*ev); if (!ev) return -ENOMEM;
ev->type = UHID_OUTPUT; ev->u.output.size = count; ev->u.output.rtype = rtype; memcpy(ev->u.output.data, buf, count);
spin_lock_irqsave(&uhid->qlock, flags); uhid_queue(uhid, ev); spin_unlock_irqrestore(&uhid->qlock, flags);
return count;}
static int uhid_hid_output_report(struct hid_device *hid, __u8 *buf, size_t count){ return uhid_hid_output_raw(hid, buf, count, HID_OUTPUT_REPORT);}
static const struct hid_ll_driver uhid_hid_driver = { .start = uhid_hid_start, .stop = uhid_hid_stop, .open = uhid_hid_open, .close = uhid_hid_close, .parse = uhid_hid_parse, .raw_request = uhid_hid_raw_request, .output_report = uhid_hid_output_report, .max_buffer_size = UHID_DATA_MAX,};
#ifdef CONFIG_COMPAT
/* Apparently we haven't stepped on these rakes enough times yet. */struct uhid_create_req_compat { __u8 name[128]; __u8 phys[64]; __u8 uniq[64];
compat_uptr_t rd_data; __u16 rd_size;
__u16 bus; __u32 vendor; __u32 product; __u32 version; __u32 country;} __attribute__((__packed__));
static int uhid_event_from_user(const char __user *buffer, size_t len, struct uhid_event *event){ if (in_compat_syscall()) { u32 type;
if (get_user(type, buffer)) return -EFAULT;
if (type == UHID_CREATE) { /* * This is our messed up request with compat pointer. * It is largish (more than 256 bytes) so we better * allocate it from the heap. */ struct uhid_create_req_compat *compat;
compat = kzalloc_obj(*compat); if (!compat) return -ENOMEM;
buffer += sizeof(type); len -= sizeof(type); if (copy_from_user(compat, buffer, min(len, sizeof(*compat)))) { kfree(compat); return -EFAULT; }
/* Shuffle the data over to proper structure */ event->type = type;
memcpy(event->u.create.name, compat->name, sizeof(compat->name)); memcpy(event->u.create.phys, compat->phys, sizeof(compat->phys)); memcpy(event->u.create.uniq, compat->uniq, sizeof(compat->uniq));
event->u.create.rd_data = compat_ptr(compat->rd_data); event->u.create.rd_size = compat->rd_size;
event->u.create.bus = compat->bus; event->u.create.vendor = compat->vendor; event->u.create.product = compat->product; event->u.create.version = compat->version; event->u.create.country = compat->country;
kfree(compat); return 0; } /* All others can be copied directly */ }
if (copy_from_user(event, buffer, min(len, sizeof(*event)))) return -EFAULT;
return 0;}#elsestatic int uhid_event_from_user(const char __user *buffer, size_t len, struct uhid_event *event){ if (copy_from_user(event, buffer, min(len, sizeof(*event)))) return -EFAULT;
return 0;}#endif
static int uhid_dev_create2(struct uhid_device *uhid, const struct uhid_event *ev){ struct hid_device *hid; size_t rd_size; void *rd_data; int ret;
if (uhid->hid) return -EALREADY;
rd_size = ev->u.create2.rd_size; if (rd_size <= 0 || rd_size > HID_MAX_DESCRIPTOR_SIZE) return -EINVAL;
rd_data = kmemdup(ev->u.create2.rd_data, rd_size, GFP_KERNEL); if (!rd_data) return -ENOMEM;
uhid->rd_size = rd_size; uhid->rd_data = rd_data;
hid = hid_allocate_device(); if (IS_ERR(hid)) { ret = PTR_ERR(hid); goto err_free; }
BUILD_BUG_ON(sizeof(hid->name) != sizeof(ev->u.create2.name)); strscpy(hid->name, ev->u.create2.name, sizeof(hid->name)); BUILD_BUG_ON(sizeof(hid->phys) != sizeof(ev->u.create2.phys)); strscpy(hid->phys, ev->u.create2.phys, sizeof(hid->phys)); BUILD_BUG_ON(sizeof(hid->uniq) != sizeof(ev->u.create2.uniq)); strscpy(hid->uniq, ev->u.create2.uniq, sizeof(hid->uniq));
hid->ll_driver = &uhid_hid_driver; hid->bus = ev->u.create2.bus; hid->vendor = ev->u.create2.vendor; hid->product = ev->u.create2.product; hid->version = ev->u.create2.version; hid->country = ev->u.create2.country; hid->driver_data = uhid; hid->dev.parent = uhid_misc.this_device;
uhid->hid = hid; uhid->running = true;
/* Adding of a HID device is done through a worker, to allow HID drivers * which use feature requests during .probe to work, without they would * be blocked on devlock, which is held by uhid_char_write. */ schedule_work(&uhid->worker);
return 0;
err_free: kfree(uhid->rd_data); uhid->rd_data = NULL; uhid->rd_size = 0; return ret;}
static int uhid_dev_create(struct uhid_device *uhid, struct uhid_event *ev){ struct uhid_create_req orig;
orig = ev->u.create;
if (orig.rd_size <= 0 || orig.rd_size > HID_MAX_DESCRIPTOR_SIZE) return -EINVAL; if (copy_from_user(&ev->u.create2.rd_data, orig.rd_data, orig.rd_size)) return -EFAULT;
memcpy(ev->u.create2.name, orig.name, sizeof(orig.name)); memcpy(ev->u.create2.phys, orig.phys, sizeof(orig.phys)); memcpy(ev->u.create2.uniq, orig.uniq, sizeof(orig.uniq)); ev->u.create2.rd_size = orig.rd_size; ev->u.create2.bus = orig.bus; ev->u.create2.vendor = orig.vendor; ev->u.create2.product = orig.product; ev->u.create2.version = orig.version; ev->u.create2.country = orig.country;
return uhid_dev_create2(uhid, ev);}
static int uhid_dev_destroy(struct uhid_device *uhid){ if (!uhid->hid) return -EINVAL;
WRITE_ONCE(uhid->running, false); wake_up_interruptible(&uhid->report_wait);
cancel_work_sync(&uhid->worker);
hid_destroy_device(uhid->hid); uhid->hid = NULL; kfree(uhid->rd_data);
return 0;}
static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev){ if (!READ_ONCE(uhid->running)) return -EINVAL;
hid_safe_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data, UHID_DATA_MAX, min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
return 0;}
static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev){ if (!READ_ONCE(uhid->running)) return -EINVAL;
hid_safe_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data, UHID_DATA_MAX, min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
return 0;}
static int uhid_dev_get_report_reply(struct uhid_device *uhid, struct uhid_event *ev){ if (!READ_ONCE(uhid->running)) return -EINVAL;
uhid_report_wake_up(uhid, ev->u.get_report_reply.id, ev); return 0;}
static int uhid_dev_set_report_reply(struct uhid_device *uhid, struct uhid_event *ev){ if (!READ_ONCE(uhid->running)) return -EINVAL;
uhid_report_wake_up(uhid, ev->u.set_report_reply.id, ev); return 0;}
static int uhid_char_open(struct inode *inode, struct file *file){ struct uhid_device *uhid;
uhid = kzalloc_obj(*uhid); if (!uhid) return -ENOMEM;
mutex_init(&uhid->devlock); mutex_init(&uhid->report_lock); spin_lock_init(&uhid->qlock); init_waitqueue_head(&uhid->waitq); init_waitqueue_head(&uhid->report_wait); uhid->running = false; INIT_WORK(&uhid->worker, uhid_device_add_worker);
file->private_data = uhid; stream_open(inode, file);
return 0;}
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]);
kfree(uhid);
return 0;}
static ssize_t uhid_char_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos){ struct uhid_device *uhid = file->private_data; int ret; unsigned long flags; size_t len;
/* they need at least the "type" member of uhid_event */ if (count < sizeof(__u32)) return -EINVAL;
try_again: if (file->f_flags & O_NONBLOCK) { if (uhid->head == uhid->tail) return -EAGAIN; } else { ret = wait_event_interruptible(uhid->waitq, uhid->head != uhid->tail); if (ret) return ret; }
ret = mutex_lock_interruptible(&uhid->devlock); if (ret) return ret;
if (uhid->head == uhid->tail) { mutex_unlock(&uhid->devlock); goto try_again; } else { len = min(count, sizeof(**uhid->outq)); if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) { ret = -EFAULT; } else { kfree(uhid->outq[uhid->tail]); uhid->outq[uhid->tail] = NULL;
spin_lock_irqsave(&uhid->qlock, flags); uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE; spin_unlock_irqrestore(&uhid->qlock, flags); } }
mutex_unlock(&uhid->devlock); return ret ? ret : len;}
static ssize_t uhid_char_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos){ struct uhid_device *uhid = file->private_data; int ret; size_t len;
/* we need at least the "type" member of uhid_event */ if (count < sizeof(__u32)) return -EINVAL;
ret = mutex_lock_interruptible(&uhid->devlock); if (ret) return ret;
memset(&uhid->input_buf, 0, sizeof(uhid->input_buf)); len = min(count, sizeof(uhid->input_buf));
ret = uhid_event_from_user(buffer, len, &uhid->input_buf); if (ret) goto unlock;
switch (uhid->input_buf.type) { case UHID_CREATE: /* * 'struct uhid_create_req' contains a __user pointer which is * copied from, so it's unsafe to allow this with elevated * privileges (e.g. from a setuid binary) or via kernel_write(). */ if (file->f_cred != current_cred()) { pr_err_once("UHID_CREATE from different security context by process %d (%s), this is not allowed.\n", task_tgid_vnr(current), current->comm); ret = -EACCES; goto unlock; } ret = uhid_dev_create(uhid, &uhid->input_buf); break; case UHID_CREATE2: ret = uhid_dev_create2(uhid, &uhid->input_buf); break; case UHID_DESTROY: ret = uhid_dev_destroy(uhid); break; case UHID_INPUT: ret = uhid_dev_input(uhid, &uhid->input_buf); break; case UHID_INPUT2: ret = uhid_dev_input2(uhid, &uhid->input_buf); break; case UHID_GET_REPORT_REPLY: ret = uhid_dev_get_report_reply(uhid, &uhid->input_buf); break; case UHID_SET_REPORT_REPLY: ret = uhid_dev_set_report_reply(uhid, &uhid->input_buf); break; default: ret = -EOPNOTSUPP; }
unlock: mutex_unlock(&uhid->devlock);
/* return "count" not "len" to not confuse the caller */ return ret ? ret : count;}
static __poll_t uhid_char_poll(struct file *file, poll_table *wait){ struct uhid_device *uhid = file->private_data; __poll_t mask = EPOLLOUT | EPOLLWRNORM; /* uhid is always writable */
poll_wait(file, &uhid->waitq, wait);
if (uhid->head != uhid->tail) mask |= EPOLLIN | EPOLLRDNORM;
return mask;}
static const struct file_operations uhid_fops = { .owner = THIS_MODULE, .open = uhid_char_open, .release = uhid_char_release, .read = uhid_char_read, .write = uhid_char_write, .poll = uhid_char_poll,};
static struct miscdevice uhid_misc = { .fops = &uhid_fops, .minor = UHID_MINOR, .name = UHID_NAME,};module_misc_device(uhid_misc);
MODULE_LICENSE("GPL");MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");MODULE_ALIAS_MISCDEV(UHID_MINOR);MODULE_ALIAS("devname:" UHID_NAME);