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n_tty: Remove overflow tests from receive_buf() path

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Always pre-figure the space available in the read_buf and limit
the inbound receive request to that amount.

For compatibility reasons with the non-flow-controlled interface,
n_tty_receive_buf() will continue filling read_buf until all data
has been received or receive_room() returns 0.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2013-07-24 08:29:54 -04:00 committed by Greg Kroah-Hartman
parent 7de971b050
commit 19e2ad6a09
1 changed files with 37 additions and 48 deletions
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85
drivers/tty/n_tty.c
View file

@ -316,12 +316,9 @@ static inline void n_tty_check_unthrottle(struct tty_struct *tty)
* not active.
*/
static void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
{
if (read_cnt(ldata) < N_TTY_BUF_SIZE) {
*read_buf_addr(ldata, ldata->read_head) = c;
ldata->read_head++;
}
*read_buf_addr(ldata, ldata->read_head++) = c;
}
/**
@ -1333,11 +1330,6 @@ n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
return;
}
if (c == '\n') {
if (read_cnt(ldata) >= N_TTY_BUF_SIZE) {
if (L_ECHO(tty))
process_output('\a', tty);
return;
}
if (L_ECHO(tty) || L_ECHONL(tty)) {
echo_char_raw('\n', ldata);
commit_echoes(tty);
@ -1345,8 +1337,6 @@ n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
goto handle_newline;
}
if (c == EOF_CHAR(tty)) {
if (read_cnt(ldata) >= N_TTY_BUF_SIZE)
return;
c = __DISABLED_CHAR;
goto handle_newline;
}
@ -1354,11 +1344,6 @@ n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
(c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty))
? 1 : 0;
if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk)) {
if (L_ECHO(tty))
process_output('\a', tty);
return;
}
/*
* XXX are EOL_CHAR and EOL2_CHAR echoed?!?
*/
@ -1388,12 +1373,6 @@ handle_newline:
}
parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) {
/* beep if no space */
if (L_ECHO(tty))
process_output('\a', tty);
return;
}
if (L_ECHO(tty)) {
finish_erasing(ldata);
if (c == '\n')
@ -1432,14 +1411,6 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
start_tty(tty);
process_echoes(tty);
}
parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) {
/* beep if no space */
if (L_ECHO(tty))
process_output('\a', tty);
return;
}
if (L_ECHO(tty)) {
finish_erasing(ldata);
/* Record the column of first canon char. */
@ -1448,6 +1419,7 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
echo_char(c, tty);
commit_echoes(tty);
}
parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
if (parmrk)
put_tty_queue(c, ldata);
put_tty_queue(c, ldata);
@ -1476,13 +1448,6 @@ n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c)
start_tty(tty);
process_echoes(tty);
}
if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - 1)) {
/* beep if no space */
if (L_ECHO(tty))
process_output('\a', tty);
return;
}
if (L_ECHO(tty)) {
finish_erasing(ldata);
/* Record the column of first canon char. */
@ -1691,8 +1656,23 @@ static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
char *fp, int count)
{
int room, n;
down_read(&tty->termios_rwsem);
__receive_buf(tty, cp, fp, count);
while (1) {
room = receive_room(tty);
n = min(count, room);
if (!n)
break;
__receive_buf(tty, cp, fp, n);
cp += n;
if (fp)
fp += n;
count -= n;
}
tty->receive_room = room;
n_tty_check_throttle(tty);
up_read(&tty->termios_rwsem);
}
@ -1701,22 +1681,31 @@ static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
char *fp, int count)
{
struct n_tty_data *ldata = tty->disc_data;
int room;
int room, n, rcvd = 0;
down_read(&tty->termios_rwsem);
tty->receive_room = room = receive_room(tty);
if (!room)
ldata->no_room = 1;
count = min(count, room);
if (count) {
__receive_buf(tty, cp, fp, count);
n_tty_check_throttle(tty);
while (1) {
room = receive_room(tty);
n = min(count, room);
if (!n) {
if (!room)
ldata->no_room = 1;
break;
}
__receive_buf(tty, cp, fp, n);
cp += n;
if (fp)
fp += n;
count -= n;
rcvd += n;
}
tty->receive_room = room;
n_tty_check_throttle(tty);
up_read(&tty->termios_rwsem);
return count;
return rcvd;
}
int is_ignored(int sig)