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termios: Protect raw input buffer with device lock

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Use the device lock to protect the raw input buffer management, e.g.
tail, head and buffer content updates.

Update #2914.
This commit is contained in:
Sebastian Huber
2017-02-23 10:06:52 +01:00
parent 35a3d81581
commit 0e8d205559
1 changed files with 36 additions and 16 deletions
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52
cpukit/libcsupport/src/termios.c
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@@ -1457,14 +1457,19 @@ fillBufferPoll (struct rtems_termios_tty *tty)
static void
fillBufferQueue (struct rtems_termios_tty *tty)
{
rtems_termios_device_context *ctx = tty->device_context;
rtems_interval timeout = tty->rawInBufSemaphoreFirstTimeout;
rtems_status_code sc;
int wait = 1;
bool wait = true;
while ( wait ) {
rtems_interrupt_lock_context lock_context;
/*
* Process characters read from raw queue
*/
rtems_termios_device_lock_acquire (ctx, &lock_context);
while ((tty->rawInBuf.Head != tty->rawInBuf.Tail) &&
(tty->ccount < (CBUFSIZE-1))) {
unsigned char c;
@@ -1473,6 +1478,7 @@ fillBufferQueue (struct rtems_termios_tty *tty)
newHead = (tty->rawInBuf.Head + 1) % tty->rawInBuf.Size;
c = tty->rawInBuf.theBuf[newHead];
tty->rawInBuf.Head = newHead;
if(((tty->rawInBuf.Tail-newHead+tty->rawInBuf.Size)
% tty->rawInBuf.Size)
< tty->lowwater) {
@@ -1494,22 +1500,30 @@ fillBufferQueue (struct rtems_termios_tty *tty)
}
}
rtems_termios_device_lock_release (ctx, &lock_context);
/* continue processing new character */
if (tty->termios.c_lflag & ICANON) {
if (siproc (c, tty))
wait = 0;
wait = false;
} else {
siproc (c, tty);
if (tty->ccount >= tty->termios.c_cc[VMIN])
wait = 0;
wait = false;
}
timeout = tty->rawInBufSemaphoreTimeout;
rtems_termios_device_lock_acquire (ctx, &lock_context);
}
rtems_termios_device_lock_release (ctx, &lock_context);
/*
* Wait for characters
*/
if ( wait ) {
rtems_status_code sc;
sc = rtems_semaphore_obtain(
tty->rawInBuf.Semaphore, tty->rawInBufSemaphoreOptions, timeout);
if (sc != RTEMS_SUCCESSFUL)
@@ -1579,7 +1593,6 @@ int
rtems_termios_enqueue_raw_characters (void *ttyp, const char *buf, int len)
{
struct rtems_termios_tty *tty = ttyp;
unsigned int newTail;
char c;
int dropped = 0;
bool flow_rcv = false; /* true, if flow control char received */
@@ -1644,12 +1657,19 @@ rtems_termios_enqueue_raw_characters (void *ttyp, const char *buf, int len)
rtems_termios_device_lock_release (ctx, &lock_context);
}
} else {
newTail = (tty->rawInBuf.Tail + 1) % tty->rawInBuf.Size;
/* if chars_in_buffer > highwater */
unsigned int head;
unsigned int oldTail;
unsigned int newTail;
rtems_termios_device_lock_acquire (ctx, &lock_context);
if ((((newTail - tty->rawInBuf.Head + tty->rawInBuf.Size)
% tty->rawInBuf.Size) > tty->highwater) &&
!(tty->flow_ctrl & FL_IREQXOF)) {
head = tty->rawInBuf.Head;
oldTail = tty->rawInBuf.Tail;
newTail = (oldTail + 1) % tty->rawInBuf.Size;
/* if chars_in_buffer > highwater */
if ((tty->flow_ctrl & FL_IREQXOF) != 0 && (((newTail - head
+ tty->rawInBuf.Size) % tty->rawInBuf.Size) > tty->highwater)) {
/* incoming data stream should be stopped */
tty->flow_ctrl |= FL_IREQXOF;
if ((tty->flow_ctrl & (FL_MDXOF | FL_ISNTXOF))
@@ -1671,15 +1691,12 @@ rtems_termios_enqueue_raw_characters (void *ttyp, const char *buf, int len)
}
}
/* reenable interrupts */
rtems_termios_device_lock_release (ctx, &lock_context);
if (newTail == tty->rawInBuf.Head) {
dropped++;
} else {
if (newTail != head) {
tty->rawInBuf.theBuf[newTail] = c;
tty->rawInBuf.Tail = newTail;
rtems_termios_device_lock_release (ctx, &lock_context);
/*
* check to see if rcv wakeup callback was set
*/
@@ -1687,6 +1704,9 @@ rtems_termios_enqueue_raw_characters (void *ttyp, const char *buf, int len)
(*tty->tty_rcv.sw_pfn)(&tty->termios, tty->tty_rcv.sw_arg);
tty->tty_rcvwakeup = 1;
}
} else {
++dropped;
rtems_termios_device_lock_release (ctx, &lock_context);
}
}
}