drivers/accessibility/speakup/devsynth.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/errno.h>
   3 #include <linux/miscdevice.h>   /* for misc_register, and MISC_DYNAMIC_MINOR */
   4 #include <linux/types.h>
   5 #include <linux/uaccess.h>
   6
   7 #include "speakup.h"
   8 #include "spk_priv.h"
   9
  10 static int synth_registered, synthu_registered;
  11 static int dev_opened;
  12
  13 /* Latin1 version */
  14 static ssize_t speakup_file_write(struct file *fp, const char __user *buffer,
  15                                   size_t nbytes, loff_t *ppos)
  16 {
  17         size_t count = nbytes;
  18         const char __user *ptr = buffer;
  19         size_t bytes;
  20         unsigned long flags;
  21         u_char buf[256];
  22
  23         if (!synth)
  24                 return -ENODEV;
  25         while (count > 0) {
  26                 bytes = min(count, sizeof(buf));
  27                 if (copy_from_user(buf, ptr, bytes))
  28                         return -EFAULT;
  29                 count -= bytes;
  30                 ptr += bytes;
  31                 spin_lock_irqsave(&speakup_info.spinlock, flags);
  32                 synth_write(buf, bytes);
  33                 spin_unlock_irqrestore(&speakup_info.spinlock, flags);
  34         }
  35         return (ssize_t)nbytes;
  36 }
  37
  38 /* UTF-8 version */
  39 static ssize_t speakup_file_writeu(struct file *fp, const char __user *buffer,
  40                                    size_t nbytes, loff_t *ppos)
  41 {
  42         size_t count = nbytes, consumed, want;
  43         const char __user *ptr = buffer;
  44         size_t bytes;
  45         unsigned long flags;
  46         unsigned char buf[256];
  47         u16 ubuf[256];
  48         size_t in, out;
  49
  50         if (!synth)
  51                 return -ENODEV;
  52
  53         want = 1;
  54         while (count >= want) {
  55                 /* Copy some UTF-8 piece from userland */
  56                 bytes = min(count, sizeof(buf));
  57                 if (copy_from_user(buf, ptr, bytes))
  58                         return -EFAULT;
  59
  60                 /* Convert to u16 */
  61                 for (in = 0, out = 0; in < bytes; in += consumed) {
  62                         s32 value;
  63
  64                         value = synth_utf8_get(buf + in, bytes - in, &consumed, &want);
  65                         if (value == -1) {
  66                                 /* Invalid or incomplete */
  67
  68                                 if (want > bytes - in)
  69                                         /* We don't have it all yet, stop here
  70                                          * and wait for the rest
  71                                          */
  72                                         bytes = in;
  73
  74                                 continue;
  75                         }
  76
  77                         if (value < 0x10000)
  78                                 ubuf[out++] = value;
  79                 }
  80
  81                 count -= bytes;
  82                 ptr += bytes;
  83
  84                 /* And speak this up */
  85                 if (out) {
  86                         spin_lock_irqsave(&speakup_info.spinlock, flags);
  87                         for (in = 0; in < out; in++)
  88                                 synth_buffer_add(ubuf[in]);
  89                         synth_start();
  90                         spin_unlock_irqrestore(&speakup_info.spinlock, flags);
  91                 }
  92         }
  93
  94         return (ssize_t)(nbytes - count);
  95 }
  96
  97 static ssize_t speakup_file_read(struct file *fp, char __user *buf,
  98                                  size_t nbytes, loff_t *ppos)
  99 {
 100         return 0;
 101 }
 102
 103 static int speakup_file_open(struct inode *ip, struct file *fp)
 104 {
 105         if (!synth)
 106                 return -ENODEV;
 107         if (xchg(&dev_opened, 1))
 108                 return -EBUSY;
 109         return 0;
 110 }
 111
 112 static int speakup_file_release(struct inode *ip, struct file *fp)
 113 {
 114         dev_opened = 0;
 115         return 0;
 116 }
 117
 118 static const struct file_operations synth_fops = {
 119         .read = speakup_file_read,
 120         .write = speakup_file_write,
 121         .open = speakup_file_open,
 122         .release = speakup_file_release,
 123 };
 124
 125 static const struct file_operations synthu_fops = {
 126         .read = speakup_file_read,
 127         .write = speakup_file_writeu,
 128         .open = speakup_file_open,
 129         .release = speakup_file_release,
 130 };
 131
 132 static struct miscdevice synth_device = {
 133         .minor = MISC_DYNAMIC_MINOR,
 134         .name = "synth",
 135         .fops = &synth_fops,
 136 };
 137
 138 static struct miscdevice synthu_device = {
 139         .minor = MISC_DYNAMIC_MINOR,
 140         .name = "synthu",
 141         .fops = &synthu_fops,
 142 };
 143
 144 void speakup_register_devsynth(void)
 145 {
 146         if (!synth_registered) {
 147                 if (misc_register(&synth_device)) {
 148                         pr_warn("Couldn't initialize miscdevice /dev/synth.\n");
 149                 } else {
 150                         pr_info("initialized device: /dev/synth, node (MAJOR %d, MINOR %d)\n",
 151                                 MISC_MAJOR, synth_device.minor);
 152                         synth_registered = 1;
 153                 }
 154         }
 155         if (!synthu_registered) {
 156                 if (misc_register(&synthu_device)) {
 157                         pr_warn("Couldn't initialize miscdevice /dev/synthu.\n");
 158                 } else {
 159                         pr_info("initialized device: /dev/synthu, node (MAJOR %d, MINOR %d)\n",
 160                                 MISC_MAJOR, synthu_device.minor);
 161                         synthu_registered = 1;
 162                 }
 163         }
 164 }
 165
 166 void speakup_unregister_devsynth(void)
 167 {
 168         if (synth_registered) {
 169                 pr_info("speakup: unregistering synth device /dev/synth\n");
 170                 misc_deregister(&synth_device);
 171                 synth_registered = 0;
 172         }
 173         if (synthu_registered) {
 174                 pr_info("speakup: unregistering synth device /dev/synthu\n");
 175                 misc_deregister(&synthu_device);
 176                 synthu_registered = 0;
 177         }
 178 }