windows: Always check return value of GetOverlappedResult().

[libserialport.git] / serialport.c

diff --git a/serialport.c b/serialport.c
index 80527be098a85eed8d624ce7ff8dd4e5dc594e12..39500f8f93fa699e17c5b13bf6292551ae388198 100644 (file)
--- a/serialport.c
+++ b/serialport.c
@@ -334,6 +334,8 @@ SP_API enum sp_return sp_list_ports(struct sp_port ***list_ptr)
        if (!list_ptr)
                RETURN_ERROR(SP_ERR_ARG, "Null result pointer");
 
+       *list_ptr = NULL;
+
 #ifdef NO_ENUMERATION
        RETURN_ERROR(SP_ERR_SUPP, "Enumeration not supported on this platform");
 #else
@@ -749,23 +751,24 @@ SP_API enum sp_return sp_blocking_write(struct sp_port *port, const void *buf,
        }
 
        /* Set timeout. */
-       port->timeouts.WriteTotalTimeoutConstant = timeout_ms;
-       if (SetCommTimeouts(port->hdl, &port->timeouts) == 0)
-               RETURN_FAIL("SetCommTimeouts() failed");
+       if (port->timeouts.WriteTotalTimeoutConstant != timeout_ms) {
+               port->timeouts.WriteTotalTimeoutConstant = timeout_ms;
+               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_FMT("Write completed, %d/%d bytes written", bytes_written, count);
-                       RETURN_INT(bytes_written);
-               } else {
-                       RETURN_FAIL("WriteFile() failed");
-               }
-       } else {
+       if (WriteFile(port->hdl, buf, count, NULL, &port->write_ovl)) {
                DEBUG("Write completed immediately");
                RETURN_INT(count);
+       } else if (GetLastError() == ERROR_IO_PENDING) {
+               DEBUG("Waiting for write to complete");
+               if (GetOverlappedResult(port->hdl, &port->write_ovl, &bytes_written, TRUE) == 0)
+                       RETURN_FAIL("GetOverlappedResult() failed");
+               DEBUG_FMT("Write completed, %d/%d bytes written", bytes_written, count);
+               RETURN_INT(bytes_written);
+       } else {
+               RETURN_FAIL("WriteFile() failed");
        }
 #else
        size_t bytes_written = 0;
@@ -862,9 +865,11 @@ SP_API enum sp_return sp_nonblocking_write(struct sp_port *port,
        }
 
        /* Set timeout. */
-       port->timeouts.WriteTotalTimeoutConstant = 0;
-       if (SetCommTimeouts(port->hdl, &port->timeouts) == 0)
-               RETURN_FAIL("SetCommTimeouts() failed");
+       if (port->timeouts.WriteTotalTimeoutConstant != 0) {
+               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
@@ -911,6 +916,26 @@ SP_API enum sp_return sp_nonblocking_write(struct sp_port *port,
 #endif
 }
 
+#ifdef _WIN32
+/* Restart wait operation if buffer was emptied. */
+static enum sp_return restart_wait_if_needed(struct sp_port *port, unsigned int bytes_read)
+{
+       DWORD errors;
+       COMSTAT comstat;
+
+       if (bytes_read == 0)
+               RETURN_OK();
+
+       if (ClearCommError(port->hdl, &errors, &comstat) == 0)
+               RETURN_FAIL("ClearCommError() failed");
+
+       if (comstat.cbInQue == 0)
+               TRY(restart_wait(port));
+
+       RETURN_OK();
+}
+#endif
+
 SP_API enum sp_return sp_blocking_read(struct sp_port *port, void *buf,
                                        size_t count, unsigned int timeout_ms)
 {
@@ -933,39 +958,30 @@ SP_API enum sp_return sp_blocking_read(struct sp_port *port, void *buf,
 
 #ifdef _WIN32
        DWORD bytes_read = 0;
-       DWORD bytes_remaining;
-       int ret;
 
        /* Set timeout. */
-       port->timeouts.ReadIntervalTimeout = 0;
-       port->timeouts.ReadTotalTimeoutConstant = timeout_ms;
-       if (SetCommTimeouts(port->hdl, &port->timeouts) == 0)
-               RETURN_FAIL("SetCommTimeouts() failed");
+       if (port->timeouts.ReadIntervalTimeout != 0 ||
+                       port->timeouts.ReadTotalTimeoutConstant != timeout_ms) {
+               port->timeouts.ReadIntervalTimeout = 0;
+               port->timeouts.ReadTotalTimeoutConstant = timeout_ms;
+               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_FMT("Read completed, %d/%d bytes read", bytes_read, count);
-               } else {
-                       RETURN_FAIL("ReadFile() failed");
-               }
-       } else {
+       if (ReadFile(port->hdl, buf, count, NULL, &port->read_ovl)) {
                DEBUG("Read completed immediately");
                bytes_read = count;
+       } else if (GetLastError() == ERROR_IO_PENDING) {
+               DEBUG("Waiting for read to complete");
+               if (GetOverlappedResult(port->hdl, &port->read_ovl, &bytes_read, TRUE) == 0)
+                       RETURN_FAIL("GetOverlappedResult() failed");
+               DEBUG_FMT("Read completed, %d/%d bytes read", bytes_read, count);
+       } else {
+               RETURN_FAIL("ReadFile() failed");
        }
 
-       ret = sp_input_waiting(port);
-
-       if (ret < 0)
-               RETURN_CODEVAL(ret);
-
-       bytes_remaining = ret;
-
-       /* Restart wait operation if buffer was emptied. */
-       if (bytes_read > 0 && bytes_remaining == 0)
-               TRY(restart_wait(port));
+       TRY(restart_wait_if_needed(port, bytes_read));
 
        RETURN_INT(bytes_read);
 
@@ -1045,14 +1061,15 @@ SP_API enum sp_return sp_nonblocking_read(struct sp_port *port, void *buf,
 
 #ifdef _WIN32
        DWORD bytes_read;
-       DWORD bytes_remaining;
-       int ret;
 
        /* Set timeout. */
-       port->timeouts.ReadIntervalTimeout = MAXDWORD;
-       port->timeouts.ReadTotalTimeoutConstant = 0;
-       if (SetCommTimeouts(port->hdl, &port->timeouts) == 0)
-               RETURN_FAIL("SetCommTimeouts() failed");
+       if (port->timeouts.ReadIntervalTimeout != MAXDWORD ||
+                       port->timeouts.ReadTotalTimeoutConstant != 0) {
+               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)
@@ -1062,16 +1079,7 @@ SP_API enum sp_return sp_nonblocking_read(struct sp_port *port, void *buf,
        if (GetOverlappedResult(port->hdl, &port->read_ovl, &bytes_read, TRUE) == 0)
                RETURN_FAIL("GetOverlappedResult() failed");
 
-       ret = sp_input_waiting(port);
-
-       if (ret < 0)
-               RETURN_CODEVAL(ret);
-
-       bytes_remaining = ret;
-
-       /* Restart wait operation if buffer was emptied. */
-       if (bytes_read > 0 && bytes_remaining == 0)
-               TRY(restart_wait(port));
+       TRY(restart_wait_if_needed(port, bytes_read));
 
        RETURN_INT(bytes_read);
 #else
@@ -2117,6 +2125,8 @@ SP_API enum sp_return sp_set_##x(struct sp_port *port, type x) { \
 SP_API enum sp_return sp_get_config_##x(const struct sp_port_config *config, \
                                         type *x) { \
        TRACE("%p, %p", config, x); \
+       if (!x) \
+               RETURN_ERROR(SP_ERR_ARG, "Null result pointer"); \
        if (!config) \
                RETURN_ERROR(SP_ERR_ARG, "Null config"); \
        *x = config->x; \
@@ -2283,10 +2293,10 @@ SP_API char *sp_last_error_message(void)
        TRACE_VOID();
 
 #ifdef _WIN32
-       LPVOID message;
+       TCHAR *message;
        DWORD error = GetLastError();
 
-       FormatMessage(
+       DWORD length = FormatMessage(
                FORMAT_MESSAGE_ALLOCATE_BUFFER |
                FORMAT_MESSAGE_FROM_SYSTEM |
                FORMAT_MESSAGE_IGNORE_INSERTS,
@@ -2296,6 +2306,9 @@ SP_API char *sp_last_error_message(void)
                (LPTSTR) &message,
                0, NULL );
 
+       if (length >= 2 && message[length - 2] == '\r')
+               message[length - 2] = '\0';
+
        RETURN_STRING(message);
 #else
        RETURN_STRING(strerror(errno));