Finally figured out a way to claim a serial port interface under unix

This commit is contained in:
roel@libnfc.org 2013-03-22 16:42:26 +00:00
parent 4a049b7847
commit 62ee4fedd5
2 changed files with 179 additions and 65 deletions

View file

@ -50,85 +50,193 @@ const struct timeval timeout = {
.tv_usec = 30000 // 30000 micro seconds
};
// Work-around to claim uart interface using the c_iflag (software input processing) from the termios struct
#define CCLAIMED 0x00008000
char pcPort[255];
serial_port uart_open(const char* pcPortName)
{
serial_port_unix* sp = malloc(sizeof(serial_port_unix));
strcpy(pcPort,pcPortName);
if (sp == 0) return INVALID_SERIAL_PORT;
sp->fd = open(pcPortName, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK);
if(sp->fd == -1)
{
if(sp->fd == -1) {
uart_close(sp);
return INVALID_SERIAL_PORT;
}
// Finally figured out a way to claim a serial port interface under unix
// We just try to set a (advisory) lock on the file descriptor
struct flock fl;
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 0;
fl.l_pid = getpid();
if(tcgetattr(sp->fd,&sp->tiOld) == -1)
{
uart_close(sp);
return INVALID_SERIAL_PORT;
}
// Make sure the port is not claimed already
if (sp->tiOld.c_iflag & CCLAIMED)
{
uart_close(sp);
// Does the system allows us to place a lock on this file descriptor
if (fcntl(sp->fd, F_SETLK, &fl) == -1) {
// A conflicting lock is held by another process
return CLAIMED_SERIAL_PORT;
}
// Copy the old terminal info struct
sp->tiNew = sp->tiOld;
sp->tiNew.c_cflag = CS8 | CLOCAL | CREAD;
sp->tiNew.c_iflag = CCLAIMED | IGNPAR;
sp->tiNew.c_oflag = 0;
sp->tiNew.c_lflag = 0;
// Set serial port equivalent to raw mode
// sp->tiNew.c_iflag &= ~(CCLAIMED | IGNBRK | BRKINT | IGNPAR | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
// sp->tiNew.c_oflag &= ~OPOST;
// sp->tiNew.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
// sp->tiNew.c_cflag &= ~(CSIZE | PARENB | CS8 | CLOCAL | CREAD);
sp->tiNew.c_cc[VMIN] = 0; // block until n bytes are received
sp->tiNew.c_cc[VTIME] = 0; // block until a timer expires (n * 100 mSec.)
if(tcsetattr(sp->fd,TCSANOW,&sp->tiNew) == -1)
{
// Try to retrieve the old (current) terminal info struct
if(tcgetattr(sp->fd,&sp->tiOld) == -1) {
uart_close(sp);
return INVALID_SERIAL_PORT;
}
// Duplicate the (old) terminal info struct
sp->tiNew = sp->tiOld;
// Configure the serial port
sp->tiNew.c_cflag = CS8 | CLOCAL | CREAD;
sp->tiNew.c_iflag = IGNPAR;
sp->tiNew.c_oflag = 0;
sp->tiNew.c_lflag = 0;
// Block until n bytes are received
sp->tiNew.c_cc[VMIN] = 0;
// Block until a timer expires (n * 100 mSec.)
sp->tiNew.c_cc[VTIME] = 0;
// Try to set the new terminal info struct
if(tcsetattr(sp->fd,TCSANOW,&sp->tiNew) == -1) {
uart_close(sp);
return INVALID_SERIAL_PORT;
}
// Flush all lingering data that may exist
tcflush(sp->fd, TCIOFLUSH);
return sp;
}
void uart_close(const serial_port sp) {
serial_port_unix* spu = (serial_port_unix*)sp;
tcflush(spu->fd,TCIOFLUSH);
tcsetattr(spu->fd,TCSANOW,&(spu->tiOld));
struct flock fl;
fl.l_type = F_UNLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 0;
fl.l_pid = getpid();
fcntl(spu->fd, F_SETLK, &fl);
close(spu->fd);
free(sp);
}
bool uart_set_speed(serial_port sp, const uint32_t uiPortSpeed) {
// Set port speed (Input and Output)
const serial_port_unix* spu = (serial_port_unix*)sp;
cfsetispeed((struct termios*)&spu->tiNew, uiPortSpeed);
cfsetospeed((struct termios*)&spu->tiNew, uiPortSpeed);
return (tcsetattr(spu->fd, TCSADRAIN, &spu->tiNew) != -1);
speed_t stPortSpeed;
switch (uiPortSpeed) {
case 0: stPortSpeed = B0; break;
case 50: stPortSpeed = B50; break;
case 75: stPortSpeed = B75; break;
case 110: stPortSpeed = B110; break;
case 134: stPortSpeed = B134; break;
case 150: stPortSpeed = B150; break;
case 300: stPortSpeed = B300; break;
case 600: stPortSpeed = B600; break;
case 1200: stPortSpeed = B1200; break;
case 1800: stPortSpeed = B1800; break;
case 2400: stPortSpeed = B2400; break;
case 4800: stPortSpeed = B4800; break;
case 9600: stPortSpeed = B9600; break;
case 19200: stPortSpeed = B19200; break;
case 38400: stPortSpeed = B38400; break;
# ifdef B57600
case 57600: stPortSpeed = B57600; break;
# endif
# ifdef B115200
case 115200: stPortSpeed = B115200; break;
# endif
# ifdef B230400
case 230400: stPortSpeed = B230400; break;
# endif
# ifdef B460800
case 460800: stPortSpeed = B460800; break;
# endif
# ifdef B921600
case 921600: stPortSpeed = B921600; break;
# endif
default: return false;
};
struct termios ti;
if (tcgetattr(spu->fd,&ti) == -1) return false;
// Set port speed (Input and Output)
cfsetispeed(&ti,stPortSpeed);
cfsetospeed(&ti,stPortSpeed);
return (tcsetattr(spu->fd,TCSANOW,&ti) != -1);
}
uint32_t uart_get_speed(const serial_port sp) {
uint32_t uiPortSpeed = 0;
struct termios ti;
uint32_t uiPortSpeed;
const serial_port_unix* spu = (serial_port_unix*)sp;
uiPortSpeed = cfgetispeed(&spu->tiNew);
if (tcgetattr(spu->fd,&ti) == -1) return 0;
// Set port speed (Input)
speed_t stPortSpeed = cfgetispeed(&ti);
switch (stPortSpeed) {
case B0: uiPortSpeed = 0; break;
case B50: uiPortSpeed = 50; break;
case B75: uiPortSpeed = 75; break;
case B110: uiPortSpeed = 110; break;
case B134: uiPortSpeed = 134; break;
case B150: uiPortSpeed = 150; break;
case B300: uiPortSpeed = 300; break;
case B600: uiPortSpeed = 600; break;
case B1200: uiPortSpeed = 1200; break;
case B1800: uiPortSpeed = 1800; break;
case B2400: uiPortSpeed = 2400; break;
case B4800: uiPortSpeed = 4800; break;
case B9600: uiPortSpeed = 9600; break;
case B19200: uiPortSpeed = 19200; break;
case B38400: uiPortSpeed = 38400; break;
# ifdef B57600
case B57600: uiPortSpeed = 57600; break;
# endif
# ifdef B115200
case B115200: uiPortSpeed = 115200; break;
# endif
# ifdef B230400
case B230400: uiPortSpeed = 230400; break;
# endif
# ifdef B460800
case B460800: uiPortSpeed = 460800; break;
# endif
# ifdef B921600
case B921600: uiPortSpeed = 921600; break;
# endif
default: return 0;
};
return uiPortSpeed;
}
void uart_close(const serial_port sp) {
tcflush(((serial_port_unix*)sp)->fd,TCIOFLUSH);
tcsetattr(((serial_port_unix*)sp)->fd,TCSANOW,&((serial_port_unix*)sp)->tiOld);
close(((serial_port_unix*)sp)->fd);
free(sp);
bool uart_set_parity(serial_port sp, serial_port_parity spp) {
struct termios ti;
const serial_port_unix* spu = (serial_port_unix*)sp;
if (tcgetattr(spu->fd,&ti) == -1) return false;
switch(spp) {
case SP_INVALID: return false;
case SP_NONE: ti.c_cflag &= ~(PARENB | PARODD); break;
case SP_EVEN: ti.c_cflag |= PARENB; ti.c_cflag &= ~(PARODD); break;
case SP_ODD: ti.c_cflag |= PARENB | PARODD; break;
}
return (tcsetattr(spu->fd,TCSANOW,&ti) != -1);
}
serial_port_parity uart_get_parity(const serial_port sp) {
struct termios ti;
const serial_port_unix* spu = (serial_port_unix*)sp;
if (tcgetattr(spu->fd,&ti) == -1) return SP_INVALID;
if (ti.c_cflag & PARENB) {
if (ti.c_cflag & PARODD) {
return SP_ODD;
} else {
return SP_EVEN;
}
} else {
return SP_NONE;
}
}
bool uart_cts(const serial_port sp) {
@ -138,6 +246,7 @@ bool uart_cts(const serial_port sp) {
}
bool uart_receive(const serial_port sp, byte_t* pbtRx, size_t* pszRxLen) {
int res;
int byteCount;
fd_set rfds;
@ -192,8 +301,7 @@ bool uart_send(const serial_port sp, const byte_t* pbtTx, const size_t szTxLen)
fd_set rfds;
struct timeval tv;
while (szPos < szTxLen)
{
while (szPos < szTxLen) {
// Reset file descriptor
FD_ZERO(&rfds);
FD_SET(((serial_port_unix*)sp)->fd,&rfds);
@ -231,12 +339,12 @@ typedef struct {
} serial_port_windows;
void upcase(char *p) {
while(*p != '\0') {
if(*p >= 97 && *p <= 122) {
*p -= 32;
while(*p != '\0') {
if(*p >= 97 && *p <= 122) {
*p -= 32;
}
++p;
}
++p;
}
}
serial_port uart_open(const char* pcPortName) {
@ -249,8 +357,7 @@ serial_port uart_open(const char* pcPortName) {
// Try to open the serial port
sp->hPort = CreateFileA(acPortName,GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);
if (sp->hPort == INVALID_HANDLE_VALUE)
{
if (sp->hPort == INVALID_HANDLE_VALUE) {
uart_close(sp);
return INVALID_SERIAL_PORT;
}
@ -258,15 +365,13 @@ serial_port uart_open(const char* pcPortName) {
// Prepare the device control
memset(&sp->dcb, 0, sizeof(DCB));
sp->dcb.DCBlength = sizeof(DCB);
if(!BuildCommDCBA("baud=9600 data=8 parity=N stop=1",&sp->dcb))
{
if(!BuildCommDCBA("baud=9600 data=8 parity=N stop=1",&sp->dcb)) {
uart_close(sp);
return INVALID_SERIAL_PORT;
}
// Update the active serial port
if(!SetCommState(sp->hPort,&sp->dcb))
{
if(!SetCommState(sp->hPort,&sp->dcb)) {
uart_close(sp);
return INVALID_SERIAL_PORT;
}
@ -277,8 +382,7 @@ serial_port uart_open(const char* pcPortName) {
sp->ct.WriteTotalTimeoutMultiplier = 0;
sp->ct.WriteTotalTimeoutConstant = 30;
if(!SetCommTimeouts(sp->hPort,&sp->ct))
{
if(!SetCommTimeouts(sp->hPort,&sp->ct)) {
uart_close(sp);
return INVALID_SERIAL_PORT;
}

View file

@ -58,6 +58,13 @@ typedef unsigned char byte_t;
#include <windows.h>
#endif
typedef enum {
SP_INVALID = 0x00, // invalid value, error occured
SP_NONE = 0x01, // no parity (default)
SP_EVEN = 0x02, // even parity
SP_ODD = 0x03 // odd parity
} serial_port_parity;
// Define shortcut to types to make code more readable
typedef void* serial_port;
#define INVALID_SERIAL_PORT (void*)(~1)
@ -69,6 +76,9 @@ void uart_close(const serial_port sp);
bool uart_set_speed(serial_port sp, const uint32_t uiPortSpeed);
uint32_t uart_get_speed(const serial_port sp);
bool uart_set_parity(serial_port sp, serial_port_parity spp);
serial_port_parity uart_get_parity(const serial_port sp);
bool uart_receive(const serial_port sp, byte_t* pbtRx, size_t* pszRxLen);
bool uart_send(const serial_port sp, const byte_t* pbtTx, const size_t szTxLen);