/* * Event char devices, giving access to raw input device events. * * Copyright (c) 1999-2002 Vojtech Pavlik * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published by * the Free Software Foundation. */ #define EVDEV_MINOR_BASE 64 #define EVDEV_MINORS 32 #define EVDEV_MIN_BUFFER_SIZE 64U #define EVDEV_BUF_PACKETS 8 #include <linux/poll.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/init.h> #include <linux/input.h> #include <linux/major.h> #include <linux/device.h> #include "input-compat.h" struct evdev { int open; int minor; struct input_handle handle; wait_queue_head_t wait; struct evdev_client *grab; struct list_head client_list; spinlock_t client_lock; /* protects client_list */ struct mutex mutex; struct device dev; bool exist; }; struct evdev_client { int head; int tail; spinlock_t buffer_lock; /* protects access to buffer, head and tail */ struct fasync_struct *fasync; struct evdev *evdev; struct list_head node; int bufsize; struct input_event buffer[]; }; static struct evdev *evdev_table[EVDEV_MINORS]; static DEFINE_MUTEX(evdev_table_mutex); static void evdev_pass_event(struct evdev_client *client, struct input_event *event) { /* * Interrupts are disabled, just acquire the lock. * Make sure we don't leave with the client buffer * "empty" by having client->head == client->tail. */ spin_lock(&client->buffer_lock); do { client->buffer[client->head++] = *event; client->head &= client->bufsize - 1; } while (client->head == client->tail); spin_unlock(&client->buffer_lock); if (event->type == EV_SYN) kill_fasync(&client->fasync, SIGIO, POLL_IN); } /* * Pass incoming event to all connected clients. */ static void evdev_event(struct input_handle *handle, unsigned int type, unsigned int code, int value) { struct evdev *evdev = handle->private; struct evdev_client *client; struct input_event event; do_gettimeofday(&event.time); event.type = type; event.code = code; event.value = value; rcu_read_lock(); client = rcu_dereference(evdev->grab); if (client) evdev_pass_event(client, &event); else list_for_each_entry_rcu(client, &evdev->client_list, node) evdev_pass_event(client, &event); rcu_read_unlock(); wake_up_interruptible(&evdev->wait); } static int evdev_fasync(int fd, struct file *file, int on) { struct evdev_client *client = file->private_data; return fasync_helper(fd, file, on, &client->fasync); } static int evdev_flush(struct file *file, fl_owner_t id) { struct evdev_client *client = file->private_data; struct evdev *evdev = client->evdev; int retval; retval = mutex_lock_interruptible(&evdev->mutex); if (retval) return retval; if (!evdev->exist) retval = -ENODEV; else retval = input_flush_device(&evdev->handle, file); mutex_unlock(&evdev->mutex); return retval; } static void evdev_free(struct device *dev) { struct evdev *evdev = container_of(dev, struct evdev, dev); input_put_device(evdev->handle.dev); kfree(evdev); } /* * Grabs an event device (along with underlying input device). * This function is called with evdev->mutex taken. */ static int evdev_grab(struct evdev *evdev, struct evdev_client *client) { int error; if (evdev->grab) return -EBUSY; error = input_grab_device(&evdev->handle); if (error) return error; rcu_assign_pointer(evdev->grab, client); synchronize_rcu(); return 0; } static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client) { if (evdev->grab != client) return -EINVAL; rcu_assign_pointer(evdev->grab, NULL); synchronize_rcu(); input_release_device(&evdev->handle); return 0; } static void evdev_attach_client(struct evdev *evdev, struct evdev_client *client) { spin_lock(&evdev->client_lock); list_add_tail_rcu(&client->node, &evdev->client_list); spin_unlock(&evdev->client_lock); synchronize_rcu(); } static void evdev_detach_client(struct evdev *evdev, struct evdev_client *client) { spin_lock(&evdev->client_lock); list_del_rcu(&client->node); spin_unlock(&evdev->client_lock); synchronize_rcu(); } static int evdev_open_device(struct evdev *evdev) { int retval; retval = mutex_lock_interruptible(&evdev->mutex); if (retval) return retval; if (!evdev->exist) retval = -ENODEV; else if (!evdev->open++) { retval = input_open_device(&evdev->handle); if (retval) evdev->open--; } mutex_unlock(&evdev->mutex); return retval; } static void evdev_close_device(struct evdev *evdev) { mutex_lock(&evdev->mutex); if (evdev->exist && !--evdev->open) input_close_device(&evdev->handle); mutex_unlock(&evdev->mutex); } /* * Wake up users waiting for IO so they can disconnect from * dead device. */ static void evdev_hangup(struct evdev *evdev) { struct evdev_client *client; spin_lock(&evdev->client_lock); list_for_each_entry(client, &evdev->client_list, node) kill_fasync(&client->fasync, SIGIO, POLL_HUP); spin_unlock(&evdev->client_lock); wake_up_interruptible(&evdev->wait); } static int evdev_release(struct inode *inode, struct file *file) { struct evdev_client *client = file->private_data; struct evdev *evdev = client->evdev; mutex_lock(&evdev->mutex); if (evdev->grab == client) evdev_ungrab(evdev, client); mutex_unlock(&evdev->mutex); evdev_detach_client(evdev, client); kfree(client); evdev_close_device(evdev); put_device(&evdev->dev); return 0; } static unsigned int evdev_compute_buffer_size(struct input_dev *dev) { unsigned int n_events = max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS, EVDEV_MIN_BUFFER_SIZE); return roundup_pow_of_two(n_events); } static int evdev_open(struct inode *inode, struct file *file) { struct evdev *evdev; struct evdev_client *client; int i = iminor(inode) - EVDEV_MINOR_BASE; unsigned int bufsize; int error; if (i >= EVDEV_MINORS) return -ENODEV; error = mutex_lock_interruptible(&evdev_table_mutex); if (error) return error; evdev = evdev_table[i]; if (evdev) get_device(&evdev->dev); mutex_unlock(&evdev_table_mutex); if (!evdev) return -ENODEV; bufsize = evdev_compute_buffer_size(evdev->handle.dev); client = kzalloc(sizeof(struct evdev_client) + bufsize * sizeof(struct input_event), GFP_KERNEL); if (!client) { error = -ENOMEM; goto err_put_evdev; } client->bufsize = bufsize; spin_lock_init(&client->buffer_lock); client->evdev = evdev; evdev_attach_client(evdev, client); error = evdev_open_device(evdev); if (error) goto err_free_client; file->private_data = client; nonseekable_open(inode, file); return 0; err_free_client: evdev_detach_client(evdev, client); kfree(client); err_put_evdev: put_device(&evdev->dev); return error; } static ssize_t evdev_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) { struct evdev_client *client = file->private_data; struct evdev *evdev = client->evdev; struct input_event event; int retval; retval = mutex_lock_interruptible(&evdev->mutex); if (retval) return retval; if (!evdev->exist) { retval = -ENODEV; goto out; } while (retval < count) { if (input_event_from_user(buffer + retval, &event)) { retval = -EFAULT; goto out; } input_inject_event(&evdev->handle, event.type, event.code, event.value); retval += input_event_size(); } out: mutex_unlock(&evdev->mutex); return retval; } static int evdev_fetch_next_event(struct evdev_client *client, struct input_event *event) { int have_event; spin_lock_irq(&client->buffer_lock); have_event = client->head != client->tail; if (have_event) { *event = client->buffer[client->tail++]; client->tail &= client->bufsize - 1; } spin_unlock_irq(&client->buffer_lock); return have_event; } static ssize_t evdev_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) { struct evdev_client *client = file->private_data; struct evdev *evdev = client->evdev; struct input_event event; int retval; if (count < input_event_size()) return -EINVAL; if (client->head == client->tail && evdev->exist && (file->f_flags & O_NONBLOCK)) return -EAGAIN; retval = wait_event_interruptible(evdev->wait, client->head != client->tail || !evdev->exist); if (retval) return retval; if (!evdev->exist) return -ENODEV; while (retval + input_event_size() <= count && evdev_fetch_next_event(client, &event)) { if (input_event_to_user(buffer + retval, &event)) return -EFAULT; retval += input_event_size(); } return retval; } /* No kernel lock - fine */ static unsigned int evdev_poll(struct file *file, poll_table *wait) { struct evdev_client *client = file->private_data; struct evdev *evdev = client->evdev; unsigned int mask; poll_wait(file, &evdev->wait, wait); mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR; if (client->head != client->tail) mask |= POLLIN | POLLRDNORM; return mask; } #ifdef CONFIG_COMPAT #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8) #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1) #ifdef __BIG_ENDIAN static int bits_to_user(unsigned long *bits, unsigned int maxbit, unsigned int maxlen, void __user *p, int compat) { int len, i; if (compat) { len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t); if (len > maxlen) len = maxlen; for (i = 0; i < len / sizeof(compat_long_t); i++) if (copy_to_user((compat_long_t __user *) p + i, (compat_long_t *) bits + i + 1 - ((i % 2) << 1), sizeof(compat_long_t))) return -EFAULT; } else { len = BITS_TO_LONGS(maxbit) * sizeof(long); if (len > maxlen) len = maxlen; if (copy_to_user(p, bits, len)) return -EFAULT; } return len; } #else static int bits_to_user(unsigned long *bits, unsigned int maxbit, unsigned int maxlen, void __user *p, int compat) { int len = compat ? BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) : BITS_TO_LONGS(maxbit) * sizeof(long); if (len > maxlen) len = maxlen; return copy_to_user(p, bits, len) ? -EFAULT : len; } #endif /* __BIG_ENDIAN */ #else static int bits_to_user(unsigned long *bits, unsigned int maxbit, unsigned int maxlen, void __user *p, int compat) { int len = BITS_TO_LONGS(maxbit) * sizeof(long); if (len > maxlen) len = maxlen; return copy_to_user(p, bits, len) ? -EFAULT : len; } #endif /* CONFIG_COMPAT */ static int str_to_user(const char *str, unsigned int maxlen, void __user *p) { int len; if (!str) return -ENOENT; len = strlen(str) + 1; if (len > maxlen) len = maxlen; return copy_to_user(p, str, len) ? -EFAULT : len; } #define OLD_KEY_MAX 0x1ff static int handle_eviocgbit(struct input_dev *dev, unsigned int type, unsigned int size, void __user *p, int compat_mode) { static unsigned long keymax_warn_time; unsigned long *bits; int len; switch (type) { case 0: bits = dev->evbit; len = EV_MAX; break; case EV_KEY: bits = dev->keybit; len = KEY_MAX; break; case EV_REL: bits = dev->relbit; len = REL_MAX; break; case EV_ABS: bits = dev->absbit; len = ABS_MAX; break; case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break; case EV_LED: bits = dev->ledbit; len = LED_MAX; break; case EV_SND: bits = dev->sndbit; len = SND_MAX; break; case EV_FF: bits = dev->ffbit; len = FF_MAX; break; case EV_SW: bits = dev->swbit; len = SW_MAX; break; default: return -EINVAL; } /* * Work around bugs in userspace programs that like to do * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len' * should be in bytes, not in bits. */ if (type == EV_KEY && size == OLD_KEY_MAX) { len = OLD_KEY_MAX; if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000)) printk(KERN_WARNING "evdev.c(EVIOCGBIT): Suspicious buffer size %u, " "limiting output to %zu bytes. See " "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n", OLD_KEY_MAX, BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long)); } return bits_to_user(bits, len, size, p, compat_mode); } #undef OLD_KEY_MAX static long evdev_do_ioctl(struct file *file, unsigned int cmd, void __user *p, int compat_mode) { struct evdev_client *client = file->private_data; struct evdev *evdev = client->evdev; struct input_dev *dev = evdev->handle.dev; struct input_absinfo abs; struct ff_effect effect; int __user *ip = (int __user *)p; unsigned int i, t, u, v; unsigned int size; int error; /* First we check for fixed-length commands */ switch (cmd) { case EVIOCGVERSION: return put_user(EV_VERSION, ip); case EVIOCGID: if (copy_to_user(p, &dev->id, sizeof(struct input_id))) return -EFAULT; return 0; case EVIOCGREP: if (!test_bit(EV_REP, dev->evbit)) return -ENOSYS; if (put_user(dev->rep[REP_DELAY], ip)) return -EFAULT; if (put_user(dev->rep[REP_PERIOD], ip + 1)) return -EFAULT; return 0; case EVIOCSREP: if (!test_bit(EV_REP, dev->evbit)) return -ENOSYS; if (get_user(u, ip)) return -EFAULT; if (get_user(v, ip + 1)) return -EFAULT; input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u); input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v); return 0; case EVIOCGKEYCODE: if (get_user(t, ip)) return -EFAULT; error = input_get_keycode(dev, t, &v); if (error) return error; if (put_user(v, ip + 1)) return -EFAULT; return 0; case EVIOCSKEYCODE: if (get_user(t, ip) || get_user(v, ip + 1)) return -EFAULT; return input_set_keycode(dev, t, v); case EVIOCRMFF: return input_ff_erase(dev, (int)(unsigned long) p, file); case EVIOCGEFFECTS: i = test_bit(EV_FF, dev->evbit) ? dev->ff->max_effects : 0; if (put_user(i, ip)) return -EFAULT; return 0; case EVIOCGRAB: if (p) return evdev_grab(evdev, client); else return evdev_ungrab(evdev, client); } size = _IOC_SIZE(cmd); /* Now check variable-length commands */ #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT)) switch (EVIOC_MASK_SIZE(cmd)) { case EVIOCGKEY(0): return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode); case EVIOCGLED(0): return bits_to_user(dev->led, LED_MAX, size, p, compat_mode); case EVIOCGSND(0): return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode); case EVIOCGSW(0): return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode); case EVIOCGNAME(0): return str_to_user(dev->name, size, p); case EVIOCGPHYS(0): return str_to_user(dev->phys, size, p); case EVIOCGUNIQ(0): return str_to_user(dev->uniq, size, p); case EVIOC_MASK_SIZE(EVIOCSFF): if (input_ff_effect_from_user(p, size, &effect)) return -EFAULT; error = input_ff_upload(dev, &effect, file); if (put_user(effect.id, &(((struct ff_effect __user *)p)->id))) return -EFAULT; return error; } /* Multi-number variable-length handlers */ if (_IOC_TYPE(cmd) != 'E') return -EINVAL; if (_IOC_DIR(cmd) == _IOC_READ) { if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) return handle_eviocgbit(dev, _IOC_NR(cmd) & EV_MAX, size, p, compat_mode); if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) { t = _IOC_NR(cmd) & ABS_MAX; abs = dev->absinfo[t]; if (copy_to_user(p, &abs, min_t(size_t, size, sizeof(struct input_absinfo)))) return -EFAULT; return 0; } } if (_IOC_DIR(cmd) == _IOC_READ) { if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) { t = _IOC_NR(cmd) & ABS_MAX; if (copy_from_user(&abs, p, min_t(size_t, size, sizeof(struct input_absinfo)))) return -EFAULT; if (size < sizeof(struct input_absinfo)) abs.resolution = 0; /* We can't change number of reserved MT slots */ if (t == ABS_MT_SLOT) return -EINVAL; /* * Take event lock to ensure that we are not * changing device parameters in the middle * of event. */ spin_lock_irq(&dev->event_lock); dev->absinfo[t] = abs; spin_unlock_irq(&dev->event_lock); return 0; } } return -EINVAL; } static long evdev_ioctl_handler(struct file *file, unsigned int cmd, void __user *p, int compat_mode) { struct evdev_client *client = file->private_data; struct evdev *evdev = client->evdev; int retval; retval = mutex_lock_interruptible(&evdev->mutex); if (retval) return retval; if (!evdev->exist) { retval = -ENODEV; goto out; } retval = evdev_do_ioctl(file, cmd, p, compat_mode); out: mutex_unlock(&evdev->mutex); return retval; } static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0); } #ifdef CONFIG_COMPAT static long evdev_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg) { return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1); } #endif static const struct file_operations evdev_fops = { .owner = THIS_MODULE, .read = evdev_read, .write = evdev_write, .poll = evdev_poll, .open = evdev_open, .release = evdev_release, .unlocked_ioctl = evdev_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = evdev_ioctl_compat, #endif .fasync = evdev_fasync, .flush = evdev_flush }; static int evdev_install_chrdev(struct evdev *evdev) { /* * No need to do any locking here as calls to connect and * disconnect are serialized by the input core */ evdev_table[evdev->minor] = evdev; return 0; } static void evdev_remove_chrdev(struct evdev *evdev) { /* * Lock evdev table to prevent race with evdev_open() */ mutex_lock(&evdev_table_mutex); evdev_table[evdev->minor] = NULL; mutex_unlock(&evdev_table_mutex); } /* * Mark device non-existent. This disables writes, ioctls and * prevents new users from opening the device. Already posted * blocking reads will stay, however new ones will fail. */ static void evdev_mark_dead(struct evdev *evdev) { mutex_lock(&evdev->mutex); evdev->exist = false; mutex_unlock(&evdev->mutex); } static void evdev_cleanup(struct evdev *evdev) { struct input_handle *handle = &evdev->handle; evdev_mark_dead(evdev); evdev_hangup(evdev); evdev_remove_chrdev(evdev); /* evdev is marked dead so no one else accesses evdev->open */ if (evdev->open) { input_flush_device(handle, NULL); input_close_device(handle); } } /* * Create new evdev device. Note that input core serializes calls * to connect and disconnect so we don't need to lock evdev_table here. */ static int evdev_connect(struct input_handler *handler, struct input_dev *dev, const struct input_device_id *id) { struct evdev *evdev; int minor; int error; for (minor = 0; minor < EVDEV_MINORS; minor++) if (!evdev_table[minor]) break; if (minor == EVDEV_MINORS) { printk(KERN_ERR "evdev: no more free evdev devices\n"); return -ENFILE; } evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); if (!evdev) return -ENOMEM; INIT_LIST_HEAD(&evdev->client_list); spin_lock_init(&evdev->client_lock); mutex_init(&evdev->mutex); init_waitqueue_head(&evdev->wait); dev_set_name(&evdev->dev, "event%d", minor); evdev->exist = true; evdev->minor = minor; evdev->handle.dev = input_get_device(dev); evdev->handle.name = dev_name(&evdev->dev); evdev->handle.handler = handler; evdev->handle.private = evdev; evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor); evdev->dev.class = &input_class; evdev->dev.parent = &dev->dev; evdev->dev.release = evdev_free; device_initialize(&evdev->dev); error = input_register_handle(&evdev->handle); if (error) goto err_free_evdev; error = evdev_install_chrdev(evdev); if (error) goto err_unregister_handle; error = device_add(&evdev->dev); if (error) goto err_cleanup_evdev; return 0; err_cleanup_evdev: evdev_cleanup(evdev); err_unregister_handle: input_unregister_handle(&evdev->handle); err_free_evdev: put_device(&evdev->dev); return error; } static void evdev_disconnect(struct input_handle *handle) { struct evdev *evdev = handle->private; device_del(&evdev->dev); evdev_cleanup(evdev); input_unregister_handle(handle); put_device(&evdev->dev); } static const struct input_device_id evdev_ids[] = { { .driver_info = 1 }, /* Matches all devices */ { }, /* Terminating zero entry */ }; MODULE_DEVICE_TABLE(input, evdev_ids); static struct input_handler evdev_handler = { .event = evdev_event, .connect = evdev_connect, .disconnect = evdev_disconnect, .fops = &evdev_fops, .minor = EVDEV_MINOR_BASE, .name = "evdev", .id_table = evdev_ids, }; static int __init evdev_init(void) { return input_register_handler(&evdev_handler); } static void __exit evdev_exit(void) { input_unregister_handler(&evdev_handler); } module_init(evdev_init); module_exit(evdev_exit); MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); MODULE_DESCRIPTION("Input driver event char devices"); MODULE_LICENSE("GPL");