windows: Await completion of previous write before changing config.

[libserialport.git] / serialport.c

diff --git a/serialport.c b/serialport.c
index d271478250f8588e0bfe03651b25f492a3d8523e..49cba74a2b2d8a6081ccb8b5825eaafbea2eb878 100644 (file)
--- a/serialport.c
+++ b/serialport.c
@@ -75,6 +75,20 @@ SP_API enum sp_return sp_get_port_by_name(const char *portname, struct sp_port *
 
        DEBUG_FMT("Building structure for port %s", portname);
 
+#if !defined(_WIN32) && defined(HAVE_REALPATH)
+       /*
+        * get_port_details() below tries to be too smart and figure out
+        * some transport properties from the port name which breaks with
+        * symlinks. Therefore we canonicalize the portname first.
+        */
+       char pathbuf[PATH_MAX + 1];
+       char *res = realpath(portname, pathbuf);
+       if (!res)
+               RETURN_ERROR(SP_ERR_ARG, "Could not retrieve realpath behind port name");
+
+       portname = pathbuf;
+#endif
+
        if (!(port = malloc(sizeof(struct sp_port))))
                RETURN_ERROR(SP_ERR_MEM, "Port structure malloc failed");
 
@@ -309,7 +323,8 @@ SP_PRIV struct sp_port **list_append(struct sp_port **list,
        void *tmp;
        unsigned int count;
 
-       for (count = 0; list[count]; count++);
+       for (count = 0; list[count]; count++)
+               ;
        if (!(tmp = realloc(list, sizeof(struct sp_port *) * (count + 2))))
                goto fail;
        list = tmp;
@@ -717,6 +732,27 @@ SP_API enum sp_return sp_drain(struct sp_port *port)
 #endif
 }
 
+#ifdef _WIN32
+static enum sp_return await_write_completion(struct sp_port *port)
+{
+       TRACE("%p", port);
+       DWORD bytes_written;
+       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");
+       }
+
+       RETURN_OK();
+}
+#endif
+
 SP_API enum sp_return sp_blocking_write(struct sp_port *port, const void *buf,
                                         size_t count, unsigned int timeout_ms)
 {
@@ -739,17 +775,8 @@ SP_API enum sp_return sp_blocking_write(struct sp_port *port, const void *buf,
 
 #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");
-       }
+       TRY(await_write_completion(port));
 
        /* Set timeout. */
        if (port->timeouts.WriteTotalTimeoutConstant != timeout_ms) {
@@ -925,10 +952,15 @@ SP_API enum sp_return sp_nonblocking_write(struct sp_port *port,
        /* Returns the number of bytes written, or -1 upon failure. */
        ssize_t written = write(port->fd, buf, count);
 
-       if (written < 0)
-               RETURN_FAIL("write() failed");
-       else
+       if (written < 0) {
+               if (errno == EAGAIN)
+                       // Buffer is full, no bytes written.
+                       RETURN_INT(0);
+               else
+                       RETURN_FAIL("write() failed");
+       } else {
                RETURN_INT(written);
+       }
 #endif
 }
 
@@ -1005,7 +1037,7 @@ SP_API enum sp_return sp_blocking_read(struct sp_port *port, void *buf,
 
 #else
        size_t bytes_read = 0;
-       unsigned char *ptr = (unsigned char *) buf;
+       unsigned char *ptr = (unsigned char *)buf;
        struct timeval start, delta, now, end = {0, 0};
        int started = 0;
        fd_set fds;
@@ -1428,7 +1460,8 @@ SP_API enum sp_return sp_wait(struct sp_event_set *event_set,
 #else
        struct timeval start, delta, now, end = {0, 0};
        const struct timeval max_delta = {
-               (INT_MAX / 1000), (INT_MAX % 1000) * 1000};
+               (INT_MAX / 1000), (INT_MAX % 1000) * 1000
+       };
        int started = 0, timeout_overflow = 0;
        int result, timeout_remaining_ms;
        struct pollfd *pollfds;
@@ -1438,7 +1471,7 @@ SP_API enum sp_return sp_wait(struct sp_event_set *event_set,
                RETURN_ERROR(SP_ERR_MEM, "pollfds malloc() failed");
 
        for (i = 0; i < event_set->count; i++) {
-               pollfds[i].fd = ((int *) event_set->handles)[i];
+               pollfds[i].fd = ((int *)event_set->handles)[i];
                pollfds[i].events = 0;
                pollfds[i].revents = 0;
                if (event_set->masks[i] & SP_EVENT_RX_READY)
@@ -1848,6 +1881,9 @@ static enum sp_return set_config(struct sp_port *port, struct port_data *data,
        DEBUG_FMT("Setting configuration for port %s", port->name);
 
 #ifdef _WIN32
+
+       TRY(await_write_completion(port));
+
        if (config->baudrate >= 0) {
                for (i = 0; i < NUM_STD_BAUDRATES; i++) {
                        if (config->baudrate == std_baudrates[i].value) {