Refactoring uart interface (#341)

* uart: Major cleanups
- Adds documentation to the uart API.
- Fixes a buffer overflow issue in `uart_receive`, where the maximum parameter was ignored.
- Splits the maximum length and bytes recieved variables in `uart_receive`.
- Downsizes the receive buffer to the minimum required, saving 16MiB of RAM at runtime.
- Refactors the POSIX and Win32 implementations of uart into separate files.
- Removes the unused `uart_{get,set}_parity` functions, which were not implemented on Win32.

uart/uart_win32.c

@@ -0,0 +1,136 @@
+/*
+ * Generic uart / rs232/ serial port library
+ *
+ * Copyright (c) 2013, Roel Verdult
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the copyright holders nor the
+ * names of its contributors may be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @file uart_win32.c
+ *
+ * Note: the win32 version of this library has also been seen under the GPLv3+
+ * license as part of the libnfc project, which appears to have additional
+ * contributors.
+ *
+ * This version of the library has functionality removed which was not used by
+ * proxmark3 project.
+ */
+
+#include "uart.h"
+
+// The windows serial port implementation
+#ifdef _WIN32
+#include <windows.h>
+
+typedef struct {
+  HANDLE hPort;     // Serial port handle
+  DCB dcb;          // Device control settings
+  COMMTIMEOUTS ct;  // Serial port time-out configuration
+} serial_port_windows;
+
+void upcase(char *p) {
+  while(*p != '\0') {
+    if(*p >= 97 && *p <= 122) {
+      *p -= 32;
+    }
+    ++p;
+  }
+}
+
+serial_port uart_open(const char* pcPortName) {
+  char acPortName[255];
+  serial_port_windows* sp = malloc(sizeof(serial_port_windows));
+  
+  // Copy the input "com?" to "\\.\COM?" format
+  sprintf(acPortName,"\\\\.\\%s",pcPortName);
+  upcase(acPortName);
+  
+  // Try to open the serial port
+  sp->hPort = CreateFileA(acPortName,GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);
+  if (sp->hPort == INVALID_HANDLE_VALUE) {
+    uart_close(sp);
+    return INVALID_SERIAL_PORT;
+  }
+  
+  // Prepare the device control
+  memset(&sp->dcb, 0, sizeof(DCB));
+  sp->dcb.DCBlength = sizeof(DCB);
+  if(!BuildCommDCBA("baud=9600 data=8 parity=N stop=1",&sp->dcb)) {
+    uart_close(sp);
+    return INVALID_SERIAL_PORT;
+  }
+  
+  // Update the active serial port
+  if(!SetCommState(sp->hPort,&sp->dcb)) {
+    uart_close(sp);
+    return INVALID_SERIAL_PORT;
+  }
+  
+  sp->ct.ReadIntervalTimeout         = 0;
+  sp->ct.ReadTotalTimeoutMultiplier  = 0;
+  sp->ct.ReadTotalTimeoutConstant    = 30;
+  sp->ct.WriteTotalTimeoutMultiplier = 0;
+  sp->ct.WriteTotalTimeoutConstant   = 30;
+  
+  if(!SetCommTimeouts(sp->hPort,&sp->ct)) {
+    uart_close(sp);
+    return INVALID_SERIAL_PORT;
+  }
+  
+  PurgeComm(sp->hPort, PURGE_RXABORT | PURGE_RXCLEAR);
+  
+  return sp;
+}
+
+void uart_close(const serial_port sp) {
+  CloseHandle(((serial_port_windows*)sp)->hPort);
+  free(sp);
+}
+
+bool uart_receive(const serial_port sp, byte_t* pbtRx, size_t pszMaxRxLen, size_t* pszRxLen) {
+  ReadFile(((serial_port_windows*)sp)->hPort,pbtRx,pszMaxRxLen,(LPDWORD)pszRxLen,NULL);
+  return (*pszRxLen != 0);
+}
+
+bool uart_send(const serial_port sp, const byte_t* pbtTx, const size_t szTxLen) {
+  DWORD dwTxLen = 0;
+  return WriteFile(((serial_port_windows*)sp)->hPort,pbtTx,szTxLen,&dwTxLen,NULL);
+  return (dwTxLen != 0);
+}
+
+bool uart_set_speed(serial_port sp, const uint32_t uiPortSpeed) {
+  serial_port_windows* spw;
+  spw = (serial_port_windows*)sp;
+  spw->dcb.BaudRate = uiPortSpeed;
+  return SetCommState(spw->hPort, &spw->dcb);
+}
+
+uint32_t uart_get_speed(const serial_port sp) {
+  const serial_port_windows* spw = (serial_port_windows*)sp;
+  if (!GetCommState(spw->hPort, (serial_port)&spw->dcb)) {
+    return spw->dcb.BaudRate;
+  }
+  return 0;
+}
+
+#endif