/usr/src/speakup-3.1.5.dfsg.1/buffers.c is in speakup 3.1.5.dfsg.1-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 | #include <linux/console.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h> /* for in_atomic */
#include <linux/types.h>
#include <linux/wait.h>
#include "speakup.h"
#include "spk_priv.h"
#define synthBufferSize 8192 /* currently 8K bytes */
static u_char synth_buffer[synthBufferSize]; /* guess what this is for! */
static u_char *buff_in = synth_buffer;
static u_char *buff_out = synth_buffer;
static u_char *buffer_end = synth_buffer+synthBufferSize-1;
/* These try to throttle applications by stopping the TTYs
* Note: we need to make sure that we will restart them eventually, which is
* usually not possible to do from the notifiers.
*
* So we only stop when we know alive == 1 (else we discard the data anyway),
* and the alive synth will eventually call start_ttys from the thread context.
*/
void speakup_start_ttys(void)
{
int i;
BUG_ON(in_atomic());
lock_kernel();
for (i = 0; i < MAX_NR_CONSOLES; i++) {
if (speakup_console[i] && speakup_console[i]->tty_stopped)
continue;
if ((vc_cons[i].d != NULL) && (vc_cons[i].d->vc_tty != NULL))
start_tty(vc_cons[i].d->vc_tty);
}
unlock_kernel();
}
EXPORT_SYMBOL_GPL(speakup_start_ttys);
static void speakup_stop_ttys(void)
{
int i;
if (!in_atomic())
lock_kernel();
else if (!kernel_locked()) {
/* BKL is not held and we are in a critical section, too bad,
* let the buffer continue to fill up.
*
* This only happens with kernel messages and keyboard echo, so
* that shouldn't be so much a concern.
*/
return;
}
for (i = 0; i < MAX_NR_CONSOLES; i++)
if ((vc_cons[i].d != NULL) && (vc_cons[i].d->vc_tty != NULL))
stop_tty(vc_cons[i].d->vc_tty);
if (!in_atomic())
unlock_kernel();
return;
}
static int synth_buffer_free(void)
{
int bytesFree;
if (buff_in >= buff_out)
bytesFree = synthBufferSize - (buff_in - buff_out);
else
bytesFree = buff_out - buff_in;
return bytesFree;
}
int synth_buffer_empty(void)
{
return (buff_in == buff_out);
}
EXPORT_SYMBOL_GPL(synth_buffer_empty);
void synth_buffer_add(char ch)
{
if (!synth->alive) {
/* This makes sure that we won't stop TTYs if there is no synth
* to restart them */
return;
}
if (synth_buffer_free() <= 100) {
synth_start();
speakup_stop_ttys();
}
if (synth_buffer_free() <= 1)
return;
*buff_in++ = ch;
if (buff_in > buffer_end)
buff_in = synth_buffer;
}
char synth_buffer_getc(void)
{
char ch;
if (buff_out == buff_in)
return 0;
ch = *buff_out++;
if (buff_out > buffer_end)
buff_out = synth_buffer;
return ch;
}
EXPORT_SYMBOL_GPL(synth_buffer_getc);
char synth_buffer_peek(void)
{
if (buff_out == buff_in)
return 0;
return *buff_out;
}
EXPORT_SYMBOL_GPL(synth_buffer_peek);
void synth_buffer_clear(void)
{
buff_in = buff_out = synth_buffer;
return;
}
EXPORT_SYMBOL_GPL(synth_buffer_clear);
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