// SPDX-License-Identifier: GPL-2.0-only/* * Event char devices, giving access to raw input device events. * * Copyright (c) 1999-2002 Vojtech Pavlik */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #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/vmalloc.h>#include <linux/mm.h>#include <linux/module.h>#include <linux/init.h>#include <linux/input/mt.h>#include <linux/major.h>#include <linux/device.h>#include <linux/cdev.h>#include "input-compat.h" struct evdev { int open; struct input_handle handle; struct evdev_client __rcu *grab; struct list_head client_list; spinlock_t client_lock; /* protects client_list */ struct mutex mutex; struct device dev; struct cdev cdev; bool exist;}; struct evdev_client { unsigned int head; unsigned int tail; unsigned int packet_head; /* [future] position of the first element of next packet */ spinlock_t buffer_lock; /* protects access to buffer, head and tail */ wait_queue_head_t wait; struct fasync_struct *fasync; struct evdev *evdev; struct list_head node; enum input_clock_type clk_type; bool revoked; unsigned long *evmasks[EV_CNT]; unsigned int bufsize; struct input_event buffer[] __counted_by(bufsize);}; static size_t evdev_get_mask_cnt(unsigned int type){ static const size_t counts[EV_CNT] = { /* EV_SYN==0 is EV_CNT, _not_ SYN_CNT, see EVIOCGBIT */ [EV_SYN] = EV_CNT, [EV_KEY] = KEY_CNT, [EV_REL] = REL_CNT, [EV_ABS] = ABS_CNT, [EV_MSC] = MSC_CNT, [EV_SW] = SW_CNT, [EV_LED] = LED_CNT, [EV_SND] = SND_CNT, [EV_FF] = FF_CNT, }; return (type < EV_CNT) ? counts[type] : 0;} /* requires the buffer lock to be held */static bool __evdev_is_filtered(struct evdev_client *client, unsigned int type, unsigned int code){ unsigned long *mask; size_t cnt; /* EV_SYN and unknown codes are never filtered */ if (type == EV_SYN || type >= EV_CNT) return false; /* first test whether the type is filtered */ mask = client->evmasks[0]; if (mask && !test_bit(type, mask)) return true; /* unknown values are never filtered */ cnt = evdev_get_mask_cnt(type); if (!cnt || code >= cnt) return false; mask = client->evmasks[type]; return mask && !test_bit(code, mask);} /* flush queued events of type @type, caller must hold client->buffer_lock */static void __evdev_flush_queue(struct evdev_client *client, unsigned int type){ unsigned int i, head, num; unsigned int mask = client->bufsize - 1; bool is_report; struct input_event *ev; BUG_ON(type == EV_SYN); head = client->tail; client->packet_head = client->tail; /* init to 1 so a leading SYN_REPORT will not be dropped */ num = 1; for (i = client->tail; i != client->head; i = (i + 1) & mask) { ev = &client->buffer[i]; is_report = ev->type == EV_SYN && ev->code == SYN_REPORT; if (ev->type == type) { /* drop matched entry */ continue; } else if (is_report && !num) { /* drop empty SYN_REPORT groups */ continue; } else if (head != i) { /* move entry to fill the gap */ client->buffer[head] = *ev; } num++; head = (head + 1) & mask; if (is_report) { num = 0; client->packet_head = head; } } client->head = head;} static void __evdev_queue_syn_dropped(struct evdev_client *client){ ktime_t *ev_time = input_get_timestamp(client->evdev->handle.dev); struct timespec64 ts = ktime_to_timespec64(ev_time[client->clk_type]); struct input_event ev; ev.input_event_sec = ts.tv_sec; ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC; ev.type = EV_SYN; ev.code = SYN_DROPPED; ev.value = 0; client->buffer[client->head++] = ev; client->head &= client->bufsize - 1; if (unlikely(client->head == client->tail)) { /* drop queue but keep our SYN_DROPPED event */ client->tail = (client->head - 1) & (client->bufsize - 1); client->packet_head = client->tail; }} static void evdev_queue_syn_dropped(struct evdev_client *client){ unsigned long flags; spin_lock_irqsave(&client->buffer_lock, flags); __evdev_queue_syn_dropped(client); spin_unlock_irqrestore(&client->buffer_lock, flags);} static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid){ unsigned long flags; enum input_clock_type clk_type; switch (clkid) { case CLOCK_REALTIME: clk_type = INPUT_CLK_REAL; break; case CLOCK_MONOTONIC: clk_type = INPUT_CLK_MONO; break; case CLOCK_BOOTTIME: clk_type = INPUT_CLK_BOOT; break; default: return -EINVAL; } if (client->clk_type != clk_type) { client->clk_type = clk_type; /* * Flush pending events and queue SYN_DROPPED event, * but only if the queue is not empty. */ spin_lock_irqsave(&client->buffer_lock, flags); if (client->head != client->tail) { client->packet_head = client->head = client->tail; __evdev_queue_syn_dropped(client); } spin_unlock_irqrestore(&client->buffer_lock, flags); } return 0;} static void __pass_event(struct evdev_client *client, const struct input_event *event){ client->buffer[client->head++] = *event; client->head &= client->bufsize - 1; if (unlikely(client->head == client->tail)) { /* * This effectively "drops" all unconsumed events, leaving * EV_SYN/SYN_DROPPED plus the newest event in the queue. */ client->tail = (client->head - 2) & (client->bufsize - 1); client->buffer[client->tail] = (struct input_event) { .input_event_sec = event->input_event_sec, .input_event_usec = event->input_event_usec, .type = EV_SYN, .code = SYN_DROPPED, .value = 0, }; client->packet_head = client->tail; } if (event->type == EV_SYN && event->code == SYN_REPORT) { client->packet_head = client->head; kill_fasync(&client->fasync, SIGIO, POLL_IN); }} static void evdev_pass_values(struct evdev_client *client, const struct input_value *vals, unsigned int count, ktime_t *ev_time){ const struct input_value *v; struct input_event event; struct timespec64 ts; bool wakeup = false; if (client->revoked) return; ts = ktime_to_timespec64(ev_time[client->clk_type]); event.input_event_sec = ts.tv_sec; event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC; /* Interrupts are disabled, just acquire the lock. */ spin_lock(&client->buffer_lock); for (v = vals; v != vals + count; v++) { if (__evdev_is_filtered(client, v->type, v->code)) continue; if (v->type == EV_SYN && v->code == SYN_REPORT) { /* drop empty SYN_REPORT */ if (client->packet_head == client->head) continue; wakeup = true; } event.type = v->type; event.code = v->code; event.value = v->value; __pass_event(client, &event); } spin_unlock(&client->buffer_lock); if (wakeup) wake_up_interruptible_poll(&client->wait, EPOLLIN | EPOLLOUT | EPOLLRDNORM | EPOLLWRNORM);} /* * Pass incoming events to all connected clients. */static unsigned int evdev_events(struct input_handle *handle, struct input_value *vals, unsigned int count){ struct evdev *evdev = handle->private; struct evdev_client *client; ktime_t *ev_time = input_get_timestamp(handle->dev); rcu_read_lock(); client = rcu_dereference(evdev->grab); if (client) evdev_pass_values(client, vals, count, ev_time); else list_for_each_entry_rcu(client, &evdev->client_list, node) evdev_pass_values(client, vals, count, ev_time); rcu_read_unlock(); return count;} 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 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); return 0;} static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client){ struct evdev_client *grab = rcu_dereference_protected(evdev->grab, lockdep_is_held(&evdev->mutex)); if (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);} 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); wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR); } spin_unlock(&evdev->client_lock);} static int evdev_release(struct inode *inode, struct file *file){ struct evdev_client *client = file->private_data; struct evdev *evdev = client->evdev; unsigned int i; mutex_lock(&evdev->mutex); if (evdev->exist && !client->revoked) input_flush_device(&evdev->handle, file); evdev_ungrab(evdev, client); mutex_unlock(&evdev->mutex); evdev_detach_client(evdev, client); for (i = 0; i < EV_CNT; ++i) bitmap_free(client->evmasks[i]); kvfree(client); evdev_close_device(evdev); 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 = container_of(inode->i_cdev, struct evdev, cdev); unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev); struct evdev_client *client; int error; client = kvzalloc(struct_size(client, buffer, bufsize), GFP_KERNEL); if (!client) return -ENOMEM; init_waitqueue_head(&client->wait); 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; stream_open(inode, file); return 0; err_free_client: evdev_detach_client(evdev, client); kvfree(client); 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 = 0; Lines 1–500 of 1446. 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// SPDX-License-Identifier: GPL-2.0-only /* * Event char devices, giving access to raw input device events. * * Copyright (c) 1999-2002 Vojtech Pavlik */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #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/vmalloc.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/init.h> #include <linux/input/mt.h> #include <linux/major.h> #include <linux/device.h> #include <linux/cdev.h> #include "input-compat.h" struct evdev { int open; struct input_handle handle; struct evdev_client __rcu *grab; struct list_head client_list; spinlock_t client_lock; /* protects client_list */ struct mutex mutex; struct device dev; struct cdev cdev; bool exist; }; struct evdev_client { unsigned int head; unsigned int tail; unsigned int packet_head; /* [future] position of the first element of next packet */ spinlock_t buffer_lock; /* protects access to buffer, head and tail */ wait_queue_head_t wait; struct fasync_struct *fasync; struct evdev *evdev; struct list_head node; enum input_clock_type clk_type; bool revoked; unsigned long *evmasks[EV_CNT]; unsigned int bufsize; struct input_event buffer[] __counted_by(bufsize); }; static size_t evdev_get_mask_cnt(unsigned int type) { static const size_t counts[EV_CNT] = { /* EV_SYN==0 is EV_CNT, _not_ SYN_CNT, see EVIOCGBIT */ [EV_SYN] = EV_CNT, [EV_KEY] = KEY_CNT, [EV_REL] = REL_CNT, [EV_ABS] = ABS_CNT, [EV_MSC] = MSC_CNT, [EV_SW] = SW_CNT, [EV_LED] = LED_CNT, [EV_SND] = SND_CNT, [EV_FF] = FF_CNT, }; return (type < EV_CNT) ? counts[type] : 0; } /* requires the buffer lock to be held */ static bool __evdev_is_filtered(struct evdev_client *client, unsigned int type, unsigned int code) { unsigned long *mask; size_t cnt; /* EV_SYN and unknown codes are never filtered */ if (type == EV_SYN || type >= EV_CNT) return false; /* first test whether the type is filtered */ mask = client->evmasks[0]; if (mask && !test_bit(type, mask)) return true; /* unknown values are never filtered */ cnt = evdev_get_mask_cnt(type); if (!cnt || code >= cnt) return false; mask = client->evmasks[type]; return mask && !test_bit(code, mask); } /* flush queued events of type @type, caller must hold client->buffer_lock */ static void __evdev_flush_queue(struct evdev_client *client, unsigned int type) { unsigned int i, head, num; unsigned int mask = client->bufsize - 1; bool is_report; struct input_event *ev; BUG_ON(type == EV_SYN); head = client->tail; client->packet_head = client->tail; /* init to 1 so a leading SYN_REPORT will not be dropped */ num = 1; for (i = client->tail; i != client->head; i = (i + 1) & mask) { ev = &client->buffer[i]; is_report = ev->type == EV_SYN && ev->code == SYN_REPORT; if (ev->type == type) { /* drop matched entry */ continue; } else if (is_report && !num) { /* drop empty SYN_REPORT groups */ continue; } else if (head != i) { /* move entry to fill the gap */ client->buffer[head] = *ev; } num++; head = (head + 1) & mask; if (is_report) { num = 0; client->packet_head = head; } } client->head = head; } static void __evdev_queue_syn_dropped(struct evdev_client *client) { ktime_t *ev_time = input_get_timestamp(client->evdev->handle.dev); struct timespec64 ts = ktime_to_timespec64(ev_time[client->clk_type]); struct input_event ev; ev.input_event_sec = ts.tv_sec; ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC; ev.type = EV_SYN; ev.code = SYN_DROPPED; ev.value = 0; client->buffer[client->head++] = ev; client->head &= client->bufsize - 1; if (unlikely(client->head == client->tail)) { /* drop queue but keep our SYN_DROPPED event */ client->tail = (client->head - 1) & (client->bufsize - 1); client->packet_head = client->tail; } } static void evdev_queue_syn_dropped(struct evdev_client *client) { unsigned long flags; spin_lock_irqsave(&client->buffer_lock, flags); __evdev_queue_syn_dropped(client); spin_unlock_irqrestore(&client->buffer_lock, flags); } static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid) { unsigned long flags; enum input_clock_type clk_type; switch (clkid) { case CLOCK_REALTIME: clk_type = INPUT_CLK_REAL; break; case CLOCK_MONOTONIC: clk_type = INPUT_CLK_MONO; break; case CLOCK_BOOTTIME: clk_type = INPUT_CLK_BOOT; break; default: return -EINVAL; } if (client->clk_type != clk_type) { client->clk_type = clk_type; /* * Flush pending events and queue SYN_DROPPED event, * but only if the queue is not empty. */ spin_lock_irqsave(&client->buffer_lock, flags); if (client->head != client->tail) { client->packet_head = client->head = client->tail; __evdev_queue_syn_dropped(client); } spin_unlock_irqrestore(&client->buffer_lock, flags); } return 0; } static void __pass_event(struct evdev_client *client, const struct input_event *event) { client->buffer[client->head++] = *event; client->head &= client->bufsize - 1; if (unlikely(client->head == client->tail)) { /* * This effectively "drops" all unconsumed events, leaving * EV_SYN/SYN_DROPPED plus the newest event in the queue. */ client->tail = (client->head - 2) & (client->bufsize - 1); client->buffer[client->tail] = (struct input_event) { .input_event_sec = event->input_event_sec, .input_event_usec = event->input_event_usec, .type = EV_SYN, .code = SYN_DROPPED, .value = 0, }; client->packet_head = client->tail; } if (event->type == EV_SYN && event->code == SYN_REPORT) { client->packet_head = client->head; kill_fasync(&client->fasync, SIGIO, POLL_IN); } } static void evdev_pass_values(struct evdev_client *client, const struct input_value *vals, unsigned int count, ktime_t *ev_time) { const struct input_value *v; struct input_event event; struct timespec64 ts; bool wakeup = false; if (client->revoked) return; ts = ktime_to_timespec64(ev_time[client->clk_type]); event.input_event_sec = ts.tv_sec; event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC; /* Interrupts are disabled, just acquire the lock. */ spin_lock(&client->buffer_lock); for (v = vals; v != vals + count; v++) { if (__evdev_is_filtered(client, v->type, v->code)) continue; if (v->type == EV_SYN && v->code == SYN_REPORT) { /* drop empty SYN_REPORT */ if (client->packet_head == client->head) continue; wakeup = true; } event.type = v->type; event.code = v->code; event.value = v->value; __pass_event(client, &event); } spin_unlock(&client->buffer_lock); if (wakeup) wake_up_interruptible_poll(&client->wait, EPOLLIN | EPOLLOUT | EPOLLRDNORM | EPOLLWRNORM); } /* * Pass incoming events to all connected clients. */ static unsigned int evdev_events(struct input_handle *handle, struct input_value *vals, unsigned int count) { struct evdev *evdev = handle->private; struct evdev_client *client; ktime_t *ev_time = input_get_timestamp(handle->dev); rcu_read_lock(); client = rcu_dereference(evdev->grab); if (client) evdev_pass_values(client, vals, count, ev_time); else list_for_each_entry_rcu(client, &evdev->client_list, node) evdev_pass_values(client, vals, count, ev_time); rcu_read_unlock(); return count; } 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 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); return 0; } static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client) { struct evdev_client *grab = rcu_dereference_protected(evdev->grab, lockdep_is_held(&evdev->mutex)); if (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); } 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); wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR); } spin_unlock(&evdev->client_lock); } static int evdev_release(struct inode *inode, struct file *file) { struct evdev_client *client = file->private_data; struct evdev *evdev = client->evdev; unsigned int i; mutex_lock(&evdev->mutex); if (evdev->exist && !client->revoked) input_flush_device(&evdev->handle, file); evdev_ungrab(evdev, client); mutex_unlock(&evdev->mutex); evdev_detach_client(evdev, client); for (i = 0; i < EV_CNT; ++i) bitmap_free(client->evmasks[i]); kvfree(client); evdev_close_device(evdev); 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 = container_of(inode->i_cdev, struct evdev, cdev); unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev); struct evdev_client *client; int error; client = kvzalloc(struct_size(client, buffer, bufsize), GFP_KERNEL); if (!client) return -ENOMEM; init_waitqueue_head(&client->wait); 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; stream_open(inode, file); return 0; err_free_client: evdev_detach_client(evdev, client); kvfree(client); 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 = 0;