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buses/uart: Use 'lockf()' for serial locking #637

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buses/uart: Use 'lockf()' for serial locking #637

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8 changes: 3 additions & 5 deletions libnfc/buses/uart.c
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Original file line number Diff line number Diff line change
Expand Up @@ -92,9 +92,6 @@ const char *serial_ports_device_radix[] = { "ttyUSB", "ttyS", "ttyACM", "ttyAMA"
# define FIONREAD TIOCINQ
#endif

// Work-around to claim uart interface using the c_iflag (software input processing) from the termios struct
# define CCLAIMED 0x80000000

struct serial_port_unix {
int fd; // Serial port file descriptor
struct termios termios_backup; // Terminal info before using the port
Expand Down Expand Up @@ -124,15 +121,15 @@ uart_open(const char *pcPortName)
return INVALID_SERIAL_PORT;
}
// Make sure the port is not claimed already
if (sp->termios_backup.c_iflag & CCLAIMED) {
if (lockf(sp->fd, F_TLOCK, 0)) {
uart_close_ext(sp, false);
return CLAIMED_SERIAL_PORT;
}
// Copy the old terminal info struct
sp->termios_new = sp->termios_backup;

sp->termios_new.c_cflag = CS8 | CLOCAL | CREAD;
sp->termios_new.c_iflag = CCLAIMED | IGNPAR;
sp->termios_new.c_iflag = IGNPAR;
sp->termios_new.c_oflag = 0;
sp->termios_new.c_lflag = 0;

Expand Down Expand Up @@ -282,6 +279,7 @@ uart_close_ext(const serial_port sp, const bool restore_termios)
if (UART_DATA(sp)->fd >= 0) {
if (restore_termios)
tcsetattr(UART_DATA(sp)->fd, TCSANOW, &UART_DATA(sp)->termios_backup);
lockf(UART_DATA(sp)->fd, F_ULOCK, 0);
close(UART_DATA(sp)->fd);
}
free(sp);
Expand Down