]> sigrok.org Git - libserialport.git/blobdiff - serialport.c
Check return value of GetOverlappedResult().
[libserialport.git] / serialport.c
index 05fb85cd06d28ebf494fe957eb8229ee94863761..b7dd66a3bfad1220d319a75fb141cae588ee47e7 100644 (file)
 #include <tchar.h>
 #include <stdio.h>
 #else
+#include <limits.h>
 #include <termios.h>
 #include <sys/ioctl.h>
+#include <sys/time.h>
+#include <limits.h>
 #endif
 #ifdef __APPLE__
 #include <IOKit/IOKitLib.h>
 #include <sys/syslimits.h>
 #endif
 #ifdef __linux__
+#ifdef HAVE_LIBUDEV
 #include "libudev.h"
+#endif
+#ifndef __ANDROID__
 #include "linux/serial.h"
+#endif
 #include "linux_termios.h"
+
+/* TCGETX/TCSETX is not available everywhere. */
 #if defined(TCGETX) && defined(TCSETX) && defined(HAVE_TERMIOX)
 #define USE_TERMIOX
 #endif
 #endif
 
+/* TIOCINQ/TIOCOUTQ is not available everywhere. */
+#if !defined(TIOCINQ) && defined(FIONREAD)
+#define TIOCINQ FIONREAD
+#endif
+#if !defined(TIOCOUTQ) && defined(FIONWRITE)
+#define TIOCOUTQ FIONWRITE
+#endif
+
 #ifndef _WIN32
 #include "linux_termios.h"
 #endif
 
 struct sp_port {
        char *name;
-       int nonblocking;
 #ifdef _WIN32
        HANDLE hdl;
+       COMMTIMEOUTS timeouts;
        OVERLAPPED write_ovl;
+       OVERLAPPED read_ovl;
        BYTE pending_byte;
        BOOL writing;
 #else
@@ -155,7 +173,11 @@ void (*sp_debug_handler)(const char *format, ...) = sp_default_debug_handler;
 #define RETURN_OK() RETURN_CODE(SP_OK);
 #define RETURN_ERROR(err, msg) do { DEBUG_ERROR(err, msg); return err; } while (0)
 #define RETURN_FAIL(msg) do { DEBUG_FAIL(msg); return SP_ERR_FAIL; } while (0)
-#define RETURN_VALUE(fmt, x) do { DEBUG("%s returning " fmt, __func__, x); return x; } while (0)
+#define RETURN_VALUE(fmt, x) do { \
+       typeof(x) _x = x; \
+       DEBUG("%s returning " fmt, __func__, _x); \
+       return _x; \
+} while (0)
 #define SET_ERROR(val, err, msg) do { DEBUG_ERROR(err, msg); val = err; } while (0)
 #define SET_FAIL(val, msg) do { DEBUG_FAIL(msg); val = SP_ERR_FAIL; } while (0)
 #define TRACE(fmt, ...) DEBUG("%s(" fmt ") called", __func__, ##__VA_ARGS__)
@@ -221,7 +243,7 @@ char *sp_get_port_name(const struct sp_port *port)
 
 enum sp_return sp_get_port_handle(const struct sp_port *port, void *result_ptr)
 {
-       TRACE("%p", port);
+       TRACE("%p, %p", port, result_ptr);
 
        if (!port)
                RETURN_ERROR(SP_ERR_ARG, "Null port");
@@ -261,8 +283,7 @@ void sp_free_port(struct sp_port *port)
 {
        TRACE("%p", port);
 
-       if (!port)
-       {
+       if (!port) {
                DEBUG("Null port");
                RETURN();
        }
@@ -447,7 +468,7 @@ out_release:
        IOObjectRelease(iter);
 out_done:
 #endif
-#ifdef __linux__
+#if defined(__linux__) && defined(HAVE_LIBUDEV)
        struct udev *ud;
        struct udev_enumerate *ud_enumerate;
        struct udev_list_entry *ud_list;
@@ -573,20 +594,21 @@ void sp_free_port_list(struct sp_port **list)
 
 enum sp_return sp_open(struct sp_port *port, enum sp_mode flags)
 {
-       TRACE("%p, %x", port, flags);
+       struct port_data data;
+       struct sp_port_config config;
+       enum sp_return ret;
+
+       TRACE("%p, 0x%x", port, flags);
 
        CHECK_PORT();
 
-       if (flags > (SP_MODE_READ | SP_MODE_WRITE | SP_MODE_NONBLOCK))
+       if (flags > (SP_MODE_READ | SP_MODE_WRITE))
                RETURN_ERROR(SP_ERR_ARG, "Invalid flags");
 
        DEBUG("Opening port %s", port->name);
 
-       port->nonblocking = (flags & SP_MODE_NONBLOCK) ? 1 : 0;
-
 #ifdef _WIN32
        DWORD desired_access = 0, flags_and_attributes = 0;
-       COMMTIMEOUTS timeouts;
        char *escaped_port_name;
 
        /* Prefix port name with '\\.\' to work with ports above COM9. */
@@ -595,13 +617,11 @@ enum sp_return sp_open(struct sp_port *port, enum sp_mode flags)
        sprintf(escaped_port_name, "\\\\.\\%s", port->name);
 
        /* Map 'flags' to the OS-specific settings. */
-       flags_and_attributes = FILE_ATTRIBUTE_NORMAL;
+       flags_and_attributes = FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED;
        if (flags & SP_MODE_READ)
                desired_access |= GENERIC_READ;
        if (flags & SP_MODE_WRITE)
                desired_access |= GENERIC_WRITE;
-       if (flags & SP_MODE_NONBLOCK)
-               flags_and_attributes |= FILE_FLAG_OVERLAPPED;
 
        port->hdl = CreateFile(escaped_port_name, desired_access, 0, 0,
                         OPEN_EXISTING, flags_and_attributes, 0);
@@ -609,36 +629,38 @@ enum sp_return sp_open(struct sp_port *port, enum sp_mode flags)
        free(escaped_port_name);
 
        if (port->hdl == INVALID_HANDLE_VALUE)
-               RETURN_FAIL("CreateFile() failed");
-
-       /* All timeouts disabled. */
-       timeouts.ReadIntervalTimeout = 0;
-       timeouts.ReadTotalTimeoutMultiplier = 0;
-       timeouts.ReadTotalTimeoutConstant = 0;
-       timeouts.WriteTotalTimeoutMultiplier = 0;
-       timeouts.WriteTotalTimeoutConstant = 0;
-
-       if (port->nonblocking) {
-               /* Set read timeout such that all reads return immediately. */
-               timeouts.ReadIntervalTimeout = MAXDWORD;
-               /* Prepare OVERLAPPED structure for non-blocking writes. */
-               memset(&port->write_ovl, 0, sizeof(port->write_ovl));
-               if (!(port->write_ovl.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL))) {
-                       sp_close(port);
-                       RETURN_FAIL("CreateEvent() failed");
-               }
-               port->writing = FALSE;
-       }
+               RETURN_FAIL("port CreateFile() failed");
+
+       /* All timeouts initially disabled. */
+       port->timeouts.ReadIntervalTimeout = 0;
+       port->timeouts.ReadTotalTimeoutMultiplier = 0;
+       port->timeouts.ReadTotalTimeoutConstant = 0;
+       port->timeouts.WriteTotalTimeoutMultiplier = 0;
+       port->timeouts.WriteTotalTimeoutConstant = 0;
 
-       if (SetCommTimeouts(port->hdl, &timeouts) == 0) {
+       if (SetCommTimeouts(port->hdl, &port->timeouts) == 0) {
                sp_close(port);
                RETURN_FAIL("SetCommTimeouts() failed");
        }
+
+       /* Prepare OVERLAPPED structures. */
+       memset(&port->read_ovl, 0, sizeof(port->read_ovl));
+       memset(&port->write_ovl, 0, sizeof(port->write_ovl));
+       port->read_ovl.hEvent = INVALID_HANDLE_VALUE;
+       port->write_ovl.hEvent = INVALID_HANDLE_VALUE;
+       if ((port->read_ovl.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL)) == INVALID_HANDLE_VALUE) {
+               sp_close(port);
+               RETURN_FAIL("read event CreateEvent() failed");
+       }
+       if ((port->write_ovl.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL)) == INVALID_HANDLE_VALUE) {
+               sp_close(port);
+               RETURN_FAIL("write event CreateEvent() failed");
+       }
+
+       port->writing = FALSE;
+
 #else
-       int flags_local = 0;
-       struct port_data data;
-       struct sp_port_config config;
-       int ret;
+       int flags_local = O_NONBLOCK | O_NOCTTY;
 
        /* Map 'flags' to the OS-specific settings. */
        if (flags & (SP_MODE_READ | SP_MODE_WRITE))
@@ -647,11 +669,10 @@ enum sp_return sp_open(struct sp_port *port, enum sp_mode flags)
                flags_local |= O_RDONLY;
        else if (flags & SP_MODE_WRITE)
                flags_local |= O_WRONLY;
-       if (flags & SP_MODE_NONBLOCK)
-               flags_local |= O_NONBLOCK;
 
        if ((port->fd = open(port->name, flags_local)) < 0)
                RETURN_FAIL("open() failed");
+#endif
 
        ret = get_config(port, &data, &config);
 
@@ -660,18 +681,51 @@ enum sp_return sp_open(struct sp_port *port, enum sp_mode flags)
                RETURN_CODEVAL(ret);
        }
 
+       /* Set sane port settings. */
+#ifdef _WIN32
+       data.dcb.fBinary = TRUE;
+       data.dcb.fDsrSensitivity = FALSE;
+       data.dcb.fErrorChar = FALSE;
+       data.dcb.fNull = FALSE;
+       data.dcb.fAbortOnError = TRUE;
+#else
        /* Turn off all fancy termios tricks, give us a raw channel. */
-       data.term.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IUCLC|IMAXBEL);
-       data.term.c_oflag &= ~(OPOST|OLCUC|ONLCR|OCRNL|ONOCR|ONLRET|NLDLY|CRDLY|TABDLY|BSDLY|VTDLY|FFDLY);
+       data.term.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IMAXBEL);
+#ifdef IUCLC
+       data.term.c_iflag &= ~IUCLC;
+#endif
+       data.term.c_oflag &= ~(OPOST | ONLCR | OCRNL | ONOCR | ONLRET);
+#ifdef OLCUC
+       data.term.c_oflag &= ~OLCUC;
+#endif
+#ifdef NLDLY
+       data.term.c_oflag &= ~NLDLY;
+#endif
+#ifdef CRDLY
+       data.term.c_oflag &= ~CRDLY;
+#endif
+#ifdef TABDLY
+       data.term.c_oflag &= ~TABDLY;
+#endif
+#ifdef BSDLY
+       data.term.c_oflag &= ~BSDLY;
+#endif
+#ifdef VTDLY
+       data.term.c_oflag &= ~VTDLY;
+#endif
+#ifdef FFDLY
+       data.term.c_oflag &= ~FFDLY;
+#endif
 #ifdef OFILL
        data.term.c_oflag &= ~OFILL;
 #endif
-       data.term.c_lflag &= ~(ISIG|ICANON|ECHO|IEXTEN);
+       data.term.c_lflag &= ~(ISIG | ICANON | ECHO | IEXTEN);
        data.term.c_cc[VMIN] = 0;
        data.term.c_cc[VTIME] = 0;
 
        /* Ignore modem status lines; enable receiver; leave control lines alone on close. */
        data.term.c_cflag |= (CLOCAL | CREAD | HUPCL);
+#endif
 
        ret = set_config(port, &data, &config);
 
@@ -679,7 +733,6 @@ enum sp_return sp_open(struct sp_port *port, enum sp_mode flags)
                sp_close(port);
                RETURN_CODEVAL(ret);
        }
-#endif
 
        RETURN_OK();
 }
@@ -695,13 +748,14 @@ enum sp_return sp_close(struct sp_port *port)
 #ifdef _WIN32
        /* Returns non-zero upon success, 0 upon failure. */
        if (CloseHandle(port->hdl) == 0)
-               RETURN_FAIL("CloseHandle() failed");
+               RETURN_FAIL("port CloseHandle() failed");
        port->hdl = INVALID_HANDLE_VALUE;
-       if (port->nonblocking) {
-               /* Close event handle created for overlapped writes. */
-               if (CloseHandle(port->write_ovl.hEvent) == 0)
-                       RETURN_FAIL("CloseHandle() failed");
-       }
+       /* Close event handle created for overlapped reads. */
+       if (port->read_ovl.hEvent != INVALID_HANDLE_VALUE && CloseHandle(port->read_ovl.hEvent) == 0)
+               RETURN_FAIL("read event CloseHandle() failed");
+       /* Close event handle created for overlapped writes. */
+       if (port->write_ovl.hEvent != INVALID_HANDLE_VALUE && CloseHandle(port->write_ovl.hEvent) == 0)
+               RETURN_FAIL("write event CloseHandle() failed");
 #else
        /* Returns 0 upon success, -1 upon failure. */
        if (close(port->fd) == -1)
@@ -714,7 +768,7 @@ enum sp_return sp_close(struct sp_port *port)
 
 enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers)
 {
-       TRACE("%p, %x", port, buffers);
+       TRACE("%p, 0x%x", port, buffers);
 
        CHECK_OPEN_PORT();
 
@@ -763,16 +817,145 @@ enum sp_return sp_drain(struct sp_port *port)
        /* Returns non-zero upon success, 0 upon failure. */
        if (FlushFileBuffers(port->hdl) == 0)
                RETURN_FAIL("FlushFileBuffers() failed");
+       RETURN_OK();
 #else
-       /* Returns 0 upon success, -1 upon failure. */
-       if (tcdrain(port->fd) < 0)
-               RETURN_FAIL("tcdrain() failed");
+       int result;
+       while (1) {
+#ifdef __ANDROID__
+               int arg = 1;
+               result = ioctl(port->fd, TCSBRK, &arg);
+#else
+               result = tcdrain(port->fd);
+#endif
+               if (result < 0) {
+                       if (errno == EINTR) {
+                               DEBUG("tcdrain() was interrupted");
+                               continue;
+                       } else {
+                               RETURN_FAIL("tcdrain() failed");
+                       }
+               } else {
+                       RETURN_OK();
+               }
+       }
 #endif
+}
 
-       RETURN_OK();
+enum sp_return sp_blocking_write(struct sp_port *port, const void *buf, size_t count, unsigned int timeout)
+{
+       TRACE("%p, %p, %d, %d", port, buf, count, timeout);
+
+       CHECK_OPEN_PORT();
+
+       if (!buf)
+               RETURN_ERROR(SP_ERR_ARG, "Null buffer");
+
+       if (timeout)
+               DEBUG("Writing %d bytes to port %s, timeout %d ms", count, port->name, timeout);
+       else
+               DEBUG("Writing %d bytes to port %s, no timeout", count, port->name);
+
+       if (count == 0)
+               RETURN_VALUE("0", 0);
+
+#ifdef _WIN32
+       DWORD bytes_written = 0;
+       BOOL result;
+
+       /* Wait for previous non-blocking write to complete, if any. */
+       if (port->writing) {
+               DEBUG("Waiting for previous write to complete");
+               result = GetOverlappedResult(port->hdl, &port->write_ovl, &bytes_written, TRUE);
+               port->writing = 0;
+               if (!result)
+                       RETURN_FAIL("Previous write failed to complete");
+               DEBUG("Previous write completed");
+       }
+
+       /* Set timeout. */
+       port->timeouts.WriteTotalTimeoutConstant = timeout;
+       if (SetCommTimeouts(port->hdl, &port->timeouts) == 0)
+               RETURN_FAIL("SetCommTimeouts() failed");
+
+       /* Start write. */
+       if (WriteFile(port->hdl, buf, count, NULL, &port->write_ovl) == 0) {
+               if (GetLastError() == ERROR_IO_PENDING) {
+                       DEBUG("Waiting for write to complete");
+                       GetOverlappedResult(port->hdl, &port->write_ovl, &bytes_written, TRUE);
+                       DEBUG("Write completed, %d/%d bytes written", bytes_written, count);
+                       RETURN_VALUE("%d", bytes_written);
+               } else {
+                       RETURN_FAIL("WriteFile() failed");
+               }
+       } else {
+               DEBUG("Write completed immediately");
+               RETURN_VALUE("%d", count);
+       }
+#else
+       size_t bytes_written = 0;
+       unsigned char *ptr = (unsigned char *) buf;
+       struct timeval start, delta, now, end = {0, 0};
+       fd_set fds;
+       int result;
+
+       if (timeout) {
+               /* Get time at start of operation. */
+               gettimeofday(&start, NULL);
+               /* Define duration of timeout. */
+               delta.tv_sec = timeout / 1000;
+               delta.tv_usec = (timeout % 1000) * 1000;
+               /* Calculate time at which we should give up. */
+               timeradd(&start, &delta, &end);
+       }
+
+       /* Loop until we have written the requested number of bytes. */
+       while (bytes_written < count)
+       {
+               /* Wait until space is available. */
+               FD_ZERO(&fds);
+               FD_SET(port->fd, &fds);
+               if (timeout) {
+                       gettimeofday(&now, NULL);
+                       if (timercmp(&now, &end, >)) {
+                               DEBUG("write timed out");
+                               RETURN_VALUE("%d", bytes_written);
+                       }
+                       timersub(&end, &now, &delta);
+               }
+               result = select(port->fd + 1, NULL, &fds, NULL, timeout ? &delta : NULL);
+               if (result < 0) {
+                       if (errno == EINTR) {
+                               DEBUG("select() call was interrupted, repeating");
+                               continue;
+                       } else {
+                               RETURN_FAIL("select() failed");
+                       }
+               } else if (result == 0) {
+                       DEBUG("write timed out");
+                       RETURN_VALUE("%d", bytes_written);
+               }
+
+               /* Do write. */
+               result = write(port->fd, ptr, count - bytes_written);
+
+               if (result < 0) {
+                       if (errno == EAGAIN)
+                               /* This shouldn't happen because we did a select() first, but handle anyway. */
+                               continue;
+                       else
+                               /* This is an actual failure. */
+                               RETURN_FAIL("write() failed");
+               }
+
+               bytes_written += result;
+               ptr += result;
+       }
+
+       RETURN_VALUE("%d", bytes_written);
+#endif
 }
 
-enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count)
+enum sp_return sp_nonblocking_write(struct sp_port *port, const void *buf, size_t count)
 {
        TRACE("%p, %p, %d", port, buf, count);
 
@@ -790,53 +973,48 @@ enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count)
        DWORD written = 0;
        BYTE *ptr = (BYTE *) buf;
 
-       if (port->nonblocking) {
-               /* Non-blocking write. */
-
-               /* Check whether previous write is complete. */
-               if (port->writing) {
-                       if (HasOverlappedIoCompleted(&port->write_ovl)) {
-                               DEBUG("Previous write completed");
-                               port->writing = 0;
-                       } else {
-                               DEBUG("Previous write not complete");
-                               /* Can't take a new write until the previous one finishes. */
-                               RETURN_VALUE("0", 0);
-                       }
+       /* Check whether previous write is complete. */
+       if (port->writing) {
+               if (HasOverlappedIoCompleted(&port->write_ovl)) {
+                       DEBUG("Previous write completed");
+                       port->writing = 0;
+               } else {
+                       DEBUG("Previous write not complete");
+                       /* Can't take a new write until the previous one finishes. */
+                       RETURN_VALUE("0", 0);
                }
+       }
 
-               /* Keep writing data until the OS has to actually start an async IO for it.
-                * At that point we know the buffer is full. */
-               while (written < count)
-               {
-                       /* Copy first byte of user buffer. */
-                       port->pending_byte = *ptr++;
-
-                       /* Start asynchronous write. */
-                       if (WriteFile(port->hdl, &port->pending_byte, 1, NULL, &port->write_ovl) == 0) {
-                               if (GetLastError() == ERROR_IO_PENDING) {
-                                       DEBUG("Asynchronous write started");
-                                       port->writing = 1;
-                                       RETURN_VALUE("%d", ++written);
-                               } else {
-                                       /* Actual failure of some kind. */
-                                       RETURN_FAIL("WriteFile() failed");
-                               }
+       /* Set timeout. */
+       port->timeouts.WriteTotalTimeoutConstant = 0;
+       if (SetCommTimeouts(port->hdl, &port->timeouts) == 0)
+               RETURN_FAIL("SetCommTimeouts() failed");
+
+       /* Keep writing data until the OS has to actually start an async IO for it.
+        * At that point we know the buffer is full. */
+       while (written < count)
+       {
+               /* Copy first byte of user buffer. */
+               port->pending_byte = *ptr++;
+
+               /* Start asynchronous write. */
+               if (WriteFile(port->hdl, &port->pending_byte, 1, NULL, &port->write_ovl) == 0) {
+                       if (GetLastError() == ERROR_IO_PENDING) {
+                               DEBUG("Asynchronous write started");
+                               port->writing = 1;
+                               RETURN_VALUE("%d", ++written);
                        } else {
-                               DEBUG("Single byte written immediately.");
-                               written++;
+                               /* Actual failure of some kind. */
+                               RETURN_FAIL("WriteFile() failed");
                        }
-               }
-
-               DEBUG("All bytes written immediately.");
-
-       } else {
-               /* Blocking write. */
-               if (WriteFile(port->hdl, buf, count, &written, NULL) == 0) {
-                       RETURN_FAIL("WriteFile() failed");
+               } else {
+                       DEBUG("Single byte written immediately.");
+                       written++;
                }
        }
 
+       DEBUG("All bytes written immediately.");
+
        RETURN_VALUE("%d", written);
 #else
        /* Returns the number of bytes written, or -1 upon failure. */
@@ -849,7 +1027,110 @@ enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count)
 #endif
 }
 
-enum sp_return sp_read(struct sp_port *port, void *buf, size_t count)
+enum sp_return sp_blocking_read(struct sp_port *port, void *buf, size_t count, unsigned int timeout)
+{
+       TRACE("%p, %p, %d, %d", port, buf, count, timeout);
+
+       CHECK_OPEN_PORT();
+
+       if (!buf)
+               RETURN_ERROR(SP_ERR_ARG, "Null buffer");
+
+       if (timeout)
+               DEBUG("Reading %d bytes from port %s, timeout %d ms", count, port->name, timeout);
+       else
+               DEBUG("Reading %d bytes from port %s, no timeout", count, port->name);
+
+       if (count == 0)
+               RETURN_VALUE("0", 0);
+
+#ifdef _WIN32
+       DWORD bytes_read = 0;
+
+       /* Set timeout. */
+       port->timeouts.ReadIntervalTimeout = 0;
+       port->timeouts.ReadTotalTimeoutConstant = timeout;
+       if (SetCommTimeouts(port->hdl, &port->timeouts) == 0)
+               RETURN_FAIL("SetCommTimeouts() failed");
+
+       /* Start read. */
+       if (ReadFile(port->hdl, buf, count, NULL, &port->read_ovl) == 0) {
+               if (GetLastError() == ERROR_IO_PENDING) {
+                       DEBUG("Waiting for read to complete");
+                       GetOverlappedResult(port->hdl, &port->read_ovl, &bytes_read, TRUE);
+                       DEBUG("Read completed, %d/%d bytes read", bytes_read, count);
+                       RETURN_VALUE("%d", bytes_read);
+               } else {
+                       RETURN_FAIL("ReadFile() failed");
+               }
+       } else {
+               DEBUG("Read completed immediately");
+               RETURN_VALUE("%d", count);
+       }
+#else
+       size_t bytes_read = 0;
+       unsigned char *ptr = (unsigned char *) buf;
+       struct timeval start, delta, now, end = {0, 0};
+       fd_set fds;
+       int result;
+
+       if (timeout) {
+               /* Get time at start of operation. */
+               gettimeofday(&start, NULL);
+               /* Define duration of timeout. */
+               delta.tv_sec = timeout / 1000;
+               delta.tv_usec = (timeout % 1000) * 1000;
+               /* Calculate time at which we should give up. */
+               timeradd(&start, &delta, &end);
+       }
+
+       /* Loop until we have the requested number of bytes. */
+       while (bytes_read < count)
+       {
+               /* Wait until data is available. */
+               FD_ZERO(&fds);
+               FD_SET(port->fd, &fds);
+               if (timeout) {
+                       gettimeofday(&now, NULL);
+                       if (timercmp(&now, &end, >))
+                               /* Timeout has expired. */
+                               RETURN_VALUE("%d", bytes_read);
+                       timersub(&end, &now, &delta);
+               }
+               result = select(port->fd + 1, &fds, NULL, NULL, timeout ? &delta : NULL);
+               if (result < 0) {
+                       if (errno == EINTR) {
+                               DEBUG("select() call was interrupted, repeating");
+                               continue;
+                       } else {
+                               RETURN_FAIL("select() failed");
+                       }
+               } else if (result == 0) {
+                       DEBUG("read timed out");
+                       RETURN_VALUE("%d", bytes_read);
+               }
+
+               /* Do read. */
+               result = read(port->fd, ptr, count - bytes_read);
+
+               if (result < 0) {
+                       if (errno == EAGAIN)
+                               /* This shouldn't happen because we did a select() first, but handle anyway. */
+                               continue;
+                       else
+                               /* This is an actual failure. */
+                               RETURN_FAIL("read() failed");
+               }
+
+               bytes_read += result;
+               ptr += result;
+       }
+
+       RETURN_VALUE("%d", bytes_read);
+#endif
+}
+
+enum sp_return sp_nonblocking_read(struct sp_port *port, void *buf, size_t count)
 {
        TRACE("%p, %p, %d", port, buf, count);
 
@@ -861,19 +1142,30 @@ enum sp_return sp_read(struct sp_port *port, void *buf, size_t count)
        DEBUG("Reading up to %d bytes from port %s", count, port->name);
 
 #ifdef _WIN32
-       DWORD bytes_read = 0;
+       DWORD bytes_read;
 
-       /* Returns non-zero upon success, 0 upon failure. */
-       if (ReadFile(port->hdl, buf, count, &bytes_read, NULL) == 0)
+       /* Set timeout. */
+       port->timeouts.ReadIntervalTimeout = MAXDWORD;
+       port->timeouts.ReadTotalTimeoutConstant = 0;
+       if (SetCommTimeouts(port->hdl, &port->timeouts) == 0)
+               RETURN_FAIL("SetCommTimeouts() failed");
+
+       /* Do read. */
+       if (ReadFile(port->hdl, buf, count, NULL, &port->read_ovl) == 0)
                RETURN_FAIL("ReadFile() failed");
+
+       /* Get number of bytes read. */
+       if (GetOverlappedResult(port->hdl, &port->read_ovl, &bytes_read, TRUE) == 0)
+               RETURN_FAIL("GetOverlappedResult() failed");
+
        RETURN_VALUE("%d", bytes_read);
 #else
        ssize_t bytes_read;
 
        /* Returns the number of bytes read, or -1 upon failure. */
        if ((bytes_read = read(port->fd, buf, count)) < 0) {
-               if (port->nonblocking && errno == EAGAIN)
-                       /* Port is opened in nonblocking mode and there are no bytes available. */
+               if (errno == EAGAIN)
+                       /* No bytes available. */
                        bytes_read = 0;
                else
                        /* This is an actual failure. */
@@ -883,6 +1175,52 @@ enum sp_return sp_read(struct sp_port *port, void *buf, size_t count)
 #endif
 }
 
+enum sp_return sp_input_waiting(struct sp_port *port)
+{
+       TRACE("%p", port);
+
+       CHECK_OPEN_PORT();
+
+       DEBUG("Checking input bytes waiting on port %s", port->name);
+
+#ifdef _WIN32
+       DWORD errors;
+       COMSTAT comstat;
+
+       if (ClearCommError(port->hdl, &errors, &comstat) == 0)
+               RETURN_FAIL("ClearComError() failed");
+       RETURN_VALUE("%d", comstat.cbInQue);
+#else
+       int bytes_waiting;
+       if (ioctl(port->fd, TIOCINQ, &bytes_waiting) < 0)
+               RETURN_FAIL("TIOCINQ ioctl failed");
+       RETURN_VALUE("%d", bytes_waiting);
+#endif
+}
+
+enum sp_return sp_output_waiting(struct sp_port *port)
+{
+       TRACE("%p", port);
+
+       CHECK_OPEN_PORT();
+
+       DEBUG("Checking output bytes waiting on port %s", port->name);
+
+#ifdef _WIN32
+       DWORD errors;
+       COMSTAT comstat;
+
+       if (ClearCommError(port->hdl, &errors, &comstat) == 0)
+               RETURN_FAIL("ClearComError() failed");
+       RETURN_VALUE("%d", comstat.cbOutQue);
+#else
+       int bytes_waiting;
+       if (ioctl(port->fd, TIOCOUTQ, &bytes_waiting) < 0)
+               RETURN_FAIL("TIOCOUTQ ioctl failed");
+       RETURN_VALUE("%d", bytes_waiting);
+#endif
+}
+
 #ifdef __linux__
 static enum sp_return get_baudrate(int fd, int *baudrate)
 {
@@ -1156,8 +1494,10 @@ static enum sp_return get_config(struct sp_port *port, struct port_data *data,
                config->parity = SP_PARITY_NONE;
        else if (!(data->term.c_cflag & PARENB) || (data->term.c_iflag & IGNPAR))
                config->parity = -1;
+#ifdef CMSPAR
        else if (data->term.c_cflag & CMSPAR)
                config->parity = (data->term.c_cflag & PARODD) ? SP_PARITY_MARK : SP_PARITY_SPACE;
+#endif
        else
                config->parity = (data->term.c_cflag & PARODD) ? SP_PARITY_ODD : SP_PARITY_EVEN;
 
@@ -1407,7 +1747,10 @@ static enum sp_return set_config(struct sp_port *port, struct port_data *data,
 
        if (config->parity >= 0) {
                data->term.c_iflag &= ~IGNPAR;
-               data->term.c_cflag &= ~(PARENB | PARODD | CMSPAR);
+               data->term.c_cflag &= ~(PARENB | PARODD);
+#ifdef CMSPAR
+               data->term.c_cflag &= ~CMSPAR;
+#endif
                switch (config->parity) {
                case SP_PARITY_NONE:
                        data->term.c_iflag |= IGNPAR;
@@ -1418,12 +1761,20 @@ static enum sp_return set_config(struct sp_port *port, struct port_data *data,
                case SP_PARITY_ODD:
                        data->term.c_cflag |= PARENB | PARODD;
                        break;
+#ifdef CMSPAR
                case SP_PARITY_MARK:
-                       data->term.c_cflag |= PARENB | PARODD | CMSPAR;
+                       data->term.c_cflag |= PARENB | PARODD;
+                       data->term.c_cflag |= CMSPAR;
                        break;
                case SP_PARITY_SPACE:
-                       data->term.c_cflag |= PARENB | CMSPAR;
+                       data->term.c_cflag |= PARENB;
+                       data->term.c_cflag |= CMSPAR;
                        break;
+#else
+               case SP_PARITY_MARK:
+               case SP_PARITY_SPACE:
+                       RETURN_ERROR(SP_ERR_SUPP, "Mark/space parity not supported");
+#endif
                default:
                        RETURN_ERROR(SP_ERR_ARG, "Invalid parity setting");
                }
@@ -1549,7 +1900,7 @@ static enum sp_return set_config(struct sp_port *port, struct port_data *data,
                }
        }
 
-       if (tcsetattr(port->fd, TCSADRAIN, &data->term) < 0)
+       if (tcsetattr(port->fd, TCSANOW, &data->term) < 0)
                RETURN_FAIL("tcsetattr() failed");
 
 #ifdef __APPLE__
@@ -1577,9 +1928,10 @@ static enum sp_return set_config(struct sp_port *port, struct port_data *data,
 
 enum sp_return sp_new_config(struct sp_port_config **config_ptr)
 {
-       TRACE("%p", config_ptr);
        struct sp_port_config *config;
 
+       TRACE("%p", config_ptr);
+
        if (!config_ptr)
                RETURN_ERROR(SP_ERR_ARG, "Null result pointer");
 
@@ -1660,7 +2012,7 @@ enum sp_return sp_set_##x(struct sp_port *port, type x) { \
        RETURN_OK(); \
 } \
 enum sp_return sp_get_config_##x(const struct sp_port_config *config, type *x) { \
-       TRACE("%p", config); \
+       TRACE("%p, %p", config, x); \
        if (!config) \
                RETURN_ERROR(SP_ERR_ARG, "Null config"); \
        *x = config->x; \
@@ -1869,7 +2221,7 @@ void sp_default_debug_handler(const char *format, ...)
        va_list args;
        va_start(args, format);
        if (getenv("LIBSERIALPORT_DEBUG")) {
-               fputs("libserialport: ", stderr);
+               fputs("sp: ", stderr);
                vfprintf(stderr, format, args);
        }
        va_end(args);