diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/speed.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/speed.c | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/sysdeps/unix/sysv/linux/speed.c b/sysdeps/unix/sysv/linux/speed.c index a0aefd805a..5a23e53fc5 100644 --- a/sysdeps/unix/sysv/linux/speed.c +++ b/sysdeps/unix/sysv/linux/speed.c @@ -22,6 +22,17 @@ #include <termios.h> +/* This is a gross hack around a kernel bug. If the cfsetispeed functions + is called with the SPEED argument set to zero this means use the same + speed as for output. But we don't have independent input and output + speeds and therefore cannot record this. + + We use an unused bit in the `c_iflag' field to keep track of this + use of `cfsetispeed'. The value here must correspond to the one used + in `tcsetattr.c'. */ +#define IBAUD0 020000000000 + + /* Return the output baud rate stored in *TERMIOS_P. */ speed_t cfgetospeed (termios_p) @@ -31,8 +42,16 @@ cfgetospeed (termios_p) } /* Return the input baud rate stored in *TERMIOS_P. - For Linux there is no difference between input and output speed. */ -strong_alias (cfgetospeed, cfgetispeed); + Although for Linux there is no difference between input and output + speed, the numerical 0 is a special case for the input baud rate. It + should set the input baud rate to the output baud rate. */ +speed_t +cfgetispeed (termios_p) + const struct termios *termios_p; +{ + return ((termios_p->c_iflag & IBAUD0) + ? 0 : termios_p->c_cflag & (CBAUD | CBAUDEX)); +} /* Set the output baud rate stored in *TERMIOS_P to SPEED. */ int @@ -47,6 +66,7 @@ cfsetospeed (termios_p, speed) return -1; } + termios_p->c_iflag &= ~IBAUD0; termios_p->c_cflag &= ~(CBAUD | CBAUDEX); termios_p->c_cflag |= speed; @@ -69,8 +89,11 @@ cfsetispeed (termios_p, speed) return -1; } - if (speed != 0) + if (speed == 0) + termios_p->c_iflag |= IBAUD0; + else { + termios_p->c_iflag &= ~IBAUD0; termios_p->c_cflag &= ~(CBAUD | CBAUDEX); termios_p->c_cflag |= speed; } |