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speakup: Add /dev/synthu device

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/dev/synth has always been 8bit, but applications nowadays mostly
expect to be using utf-8 encoding.  This adds /dev/synthu to be able
to synthesize non-latin1 characters.  This however remains limited
to 16bit unicode like the rest of speakup.  Any odd input or input
beyond 16bit is just discarded.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

===================================================================
Link: https://lore.kernel.org/r/20240204155825.ditstifsbqndnce3@begin

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Samuel Thibault 2024-02-04 16:58:25 +01:00 committed by Greg Kroah-Hartman
parent b6c8dafc9d
commit 807977260a
1 changed files with 133 additions and 15 deletions
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148
drivers/accessibility/speakup/devsynth.c
View file

@ -7,9 +7,10 @@
#include "speakup.h"
#include "spk_priv.h"
static int misc_registered;
static int synth_registered, synthu_registered;
static int dev_opened;
/* Latin1 version */
static ssize_t speakup_file_write(struct file *fp, const char __user *buffer,
size_t nbytes, loff_t *ppos)
{
@ -34,6 +35,97 @@ static ssize_t speakup_file_write(struct file *fp, const char __user *buffer,
return (ssize_t)nbytes;
}
/* UTF-8 version */
static ssize_t speakup_file_writeu(struct file *fp, const char __user *buffer,
size_t nbytes, loff_t *ppos)
{
size_t count = nbytes, want;
const char __user *ptr = buffer;
size_t bytes;
unsigned long flags;
unsigned char buf[256];
u16 ubuf[256];
size_t in, in2, out;
if (!synth)
return -ENODEV;
want = 1;
while (count >= want) {
/* Copy some UTF-8 piece from userland */
bytes = min(count, sizeof(buf));
if (copy_from_user(buf, ptr, bytes))
return -EFAULT;
/* Convert to u16 */
for (in = 0, out = 0; in < bytes; in++) {
unsigned char c = buf[in];
int nbytes = 8 - fls(c ^ 0xff);
u32 value;
switch (nbytes) {
case 8: /* 0xff */
case 7: /* 0xfe */
case 1: /* 0x80 */
/* Invalid, drop */
goto drop;
case 0:
/* ASCII, copy */
ubuf[out++] = c;
continue;
default:
/* 2..6-byte UTF-8 */
if (bytes - in < nbytes) {
/* We don't have it all yet, stop here
* and wait for the rest
*/
bytes = in;
want = nbytes;
continue;
}
/* First byte */
value = c & ((1u << (7 - nbytes)) - 1);
/* Other bytes */
for (in2 = 2; in2 <= nbytes; in2++) {
c = buf[in + 1];
if ((c & 0xc0) != 0x80) {
/* Invalid, drop the head */
want = 1;
goto drop;
}
value = (value << 6) | (c & 0x3f);
in++;
}
if (value < 0x10000)
ubuf[out++] = value;
want = 1;
break;
}
drop:
}
count -= bytes;
ptr += bytes;
/* And speak this up */
if (out) {
spin_lock_irqsave(&speakup_info.spinlock, flags);
for (in = 0; in < out; in++)
synth_buffer_add(ubuf[in]);
synth_start();
spin_unlock_irqrestore(&speakup_info.spinlock, flags);
}
}
return (ssize_t)(nbytes - count);
}
static ssize_t speakup_file_read(struct file *fp, char __user *buf,
size_t nbytes, loff_t *ppos)
{
@ -62,31 +154,57 @@ static const struct file_operations synth_fops = {
.release = speakup_file_release,
};
static const struct file_operations synthu_fops = {
.read = speakup_file_read,
.write = speakup_file_writeu,
.open = speakup_file_open,
.release = speakup_file_release,
};
static struct miscdevice synth_device = {
.minor = MISC_DYNAMIC_MINOR,
.name = "synth",
.fops = &synth_fops,
};
static struct miscdevice synthu_device = {
.minor = MISC_DYNAMIC_MINOR,
.name = "synthu",
.fops = &synthu_fops,
};
void speakup_register_devsynth(void)
{
if (misc_registered != 0)
return;
/* zero it so if register fails, deregister will not ref invalid ptrs */
if (misc_register(&synth_device)) {
pr_warn("Couldn't initialize miscdevice /dev/synth.\n");
} else {
pr_info("initialized device: /dev/synth, node (MAJOR %d, MINOR %d)\n",
MISC_MAJOR, synth_device.minor);
misc_registered = 1;
if (!synth_registered) {
if (misc_register(&synth_device)) {
pr_warn("Couldn't initialize miscdevice /dev/synth.\n");
} else {
pr_info("initialized device: /dev/synth, node (MAJOR %d, MINOR %d)\n",
MISC_MAJOR, synth_device.minor);
synth_registered = 1;
}
}
if (!synthu_registered) {
if (misc_register(&synthu_device)) {
pr_warn("Couldn't initialize miscdevice /dev/synthu.\n");
} else {
pr_info("initialized device: /dev/synthu, node (MAJOR %d, MINOR %d)\n",
MISC_MAJOR, synthu_device.minor);
synthu_registered = 1;
}
}
}
void speakup_unregister_devsynth(void)
{
if (!misc_registered)
return;
pr_info("speakup: unregistering synth device /dev/synth\n");
misc_deregister(&synth_device);
misc_registered = 0;
if (synth_registered) {
pr_info("speakup: unregistering synth device /dev/synth\n");
misc_deregister(&synth_device);
synth_registered = 0;
}
if (synthu_registered) {
pr_info("speakup: unregistering synth device /dev/synthu\n");
misc_deregister(&synthu_device);
synthu_registered = 0;
}
}