Change sp_openserport() to directly clear the O_NONBLOCK flag that is potentially set by opening the device with O_NDELAY instead of clearing ALL flags in serialport_config() unconditionally.
Signed-off-by: Stefan Tauner stefan.tauner@alumni.tuwien.ac.at --- serial.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/serial.c b/serial.c index 94f9b7d..63774a5 100644 --- a/serial.c +++ b/serial.c @@ -183,10 +183,6 @@ int serialport_config(fdtype fd, unsigned int baud) msg_pdbg("Baud rate is %ld.\n", dcb.BaudRate); #else struct termios wanted, observed; - if (fcntl(fd, F_SETFL, 0) != 0) { - msg_perr_strerror("Could not clear serial port mode: "); - return 1; - } if (tcgetattr(fd, &observed) != 0) { msg_perr_strerror("Could not fetch original serial port configuration: "); return 1; @@ -254,11 +250,23 @@ fdtype sp_openserport(char *dev, unsigned int baud) } return fd; #else - fd = open(dev, O_RDWR | O_NOCTTY | O_NDELAY); + fd = open(dev, O_RDWR | O_NOCTTY | O_NDELAY); // Use O_NDELAY to ignore DCD state if (fd < 0) { msg_perr_strerror("Cannot open serial port: "); return SER_INV_FD; } + + /* Ensure that we use blocking I/O */ + const int flags = fcntl(fd, F_GETFL); + if (flags == -1) { + msg_perr_strerror("Could not get serial port mode: "); + return SER_INV_FD; + } + if (fcntl(fd, F_SETFL, flags & ~O_NONBLOCK) != 0) { + msg_perr_strerror("Could not set serial port mode to blocking: "); + return SER_INV_FD; + } + if (serialport_config(fd, baud) != 0) { close(fd); return SER_INV_FD;