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// +build !windows,cgo
package serial
// #include <termios.h>
// #include <unistd.h>
import "C"
// TODO: Maybe change to using syscall package + ioctl instead of cgo
import (
"errors"
"fmt"
"os"
"syscall"
"time"
//"unsafe"
)
func openPort(name string, baud int, readTimeout time.Duration) (p *Port, err error) {
f, err := os.OpenFile(name, syscall.O_RDWR|syscall.O_NOCTTY|syscall.O_NONBLOCK, 0666)
if err != nil {
return
}
fd := C.int(f.Fd())
if C.isatty(fd) != 1 {
f.Close()
return nil, errors.New("File is not a tty")
}
var st C.struct_termios
_, err = C.tcgetattr(fd, &st)
if err != nil {
f.Close()
return nil, err
}
var speed C.speed_t
switch baud {
case 115200:
speed = C.B115200
case 57600:
speed = C.B57600
case 38400:
speed = C.B38400
case 19200:
speed = C.B19200
case 9600:
speed = C.B9600
case 4800:
speed = C.B4800
case 2400:
speed = C.B2400
default:
f.Close()
return nil, fmt.Errorf("Unknown baud rate %v", baud)
}
_, err = C.cfsetispeed(&st, speed)
if err != nil {
f.Close()
return nil, err
}
_, err = C.cfsetospeed(&st, speed)
if err != nil {
f.Close()
return nil, err
}
// Turn off break interrupts, CR->NL, Parity checks, strip, and IXON
st.c_iflag &= ^C.tcflag_t(C.BRKINT | C.ICRNL | C.INPCK | C.ISTRIP | C.IXOFF | C.IXON | C.PARMRK)
// Select local mode, turn off parity, set to 8 bits
st.c_cflag &= ^C.tcflag_t(C.CSIZE | C.PARENB)
st.c_cflag |= (C.CLOCAL | C.CREAD | C.CS8)
// Select raw mode
st.c_lflag &= ^C.tcflag_t(C.ICANON | C.ECHO | C.ECHOE | C.ISIG)
st.c_oflag &= ^C.tcflag_t(C.OPOST)
// set blocking / non-blocking read
/*
* http://man7.org/linux/man-pages/man3/termios.3.html
* - Supports blocking read and read with timeout operations
*/
vmin, vtime := posixTimeoutValues(readTimeout)
st.c_cc[C.VMIN] = C.cc_t(vmin)
st.c_cc[C.VTIME] = C.cc_t(vtime)
_, err = C.tcsetattr(fd, C.TCSANOW, &st)
if err != nil {
f.Close()
return nil, err
}
//fmt.Println("Tweaking", name)
r1, _, e := syscall.Syscall(syscall.SYS_FCNTL,
uintptr(f.Fd()),
uintptr(syscall.F_SETFL),
uintptr(0))
if e != 0 || r1 != 0 {
s := fmt.Sprint("Clearing NONBLOCK syscall error:", e, r1)
f.Close()
return nil, errors.New(s)
}
/*
r1, _, e = syscall.Syscall(syscall.SYS_IOCTL,
uintptr(f.Fd()),
uintptr(0x80045402), // IOSSIOSPEED
uintptr(unsafe.Pointer(&baud)));
if e != 0 || r1 != 0 {
s := fmt.Sprint("Baudrate syscall error:", e, r1)
f.Close()
return nil, os.NewError(s)
}
*/
return &Port{f: f}, nil
}
type Port struct {
// We intentionly do not use an "embedded" struct so that we
// don't export File
f *os.File
}
func (p *Port) Read(b []byte) (n int, err error) {
return p.f.Read(b)
}
func (p *Port) Write(b []byte) (n int, err error) {
return p.f.Write(b)
}
// Discards data written to the port but not transmitted,
// or data received but not read
func (p *Port) Flush() error {
_, err := C.tcflush(C.int(p.f.Fd()), C.TCIOFLUSH)
return err
}
func (p *Port) Close() (err error) {
return p.f.Close()
}
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