From 23af9327a53b865383271e5844f75997671b32aa Mon Sep 17 00:00:00 2001
From: pwpiwi <pwpiwi@users.noreply.github.com>
Date: Tue, 24 Oct 2017 07:48:38 +0200
Subject: [PATCH] fix hw status (and USB comm in general) (#434)

* don't ignore ReadLine() errors (Windows)
* lock CmdBuffer with Mutex
* refactor WaitForResponseTimeoutW
---
 client/cmdmain.c   | 26 +++++++++++++++++++++-----
 client/proxmark3.c |  3 +--
 uart/uart_win32.c  |  8 +++-----
 3 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/client/cmdmain.c b/client/cmdmain.c
index db88b3ac..739d68e1 100644
--- a/client/cmdmain.c
+++ b/client/cmdmain.c
@@ -8,6 +8,9 @@
 // Main command parser entry point
 //-----------------------------------------------------------------------------
 
+#include "cmdmain.h"
+
+#include <pthread.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -21,7 +24,6 @@
 #include "cmddata.h"
 #include "cmdhw.h"
 #include "cmdlf.h"
-#include "cmdmain.h"
 #include "util.h"
 #include "util_posix.h"
 #include "cmdscript.h"
@@ -41,6 +43,8 @@ static UsbCommand cmdBuffer[CMD_BUFFER_SIZE];
 static int cmd_head;//Starts as 0
 //Points to the position of the last unread command
 static int cmd_tail;//Starts as 0
+// to lock cmdBuffer operations from different threads
+static pthread_mutex_t cmdBufferMutex = PTHREAD_MUTEX_INITIALIZER;
 
 static command_t CommandTable[] = 
 {
@@ -86,7 +90,9 @@ int CmdRev(const char *Cmd)
 void clearCommandBuffer()
 {
     //This is a very simple operation
+	pthread_mutex_lock(&cmdBufferMutex);
     cmd_tail = cmd_head;
+	pthread_mutex_unlock(&cmdBufferMutex);
 }
 
 /**
@@ -95,6 +101,7 @@ void clearCommandBuffer()
  */
 void storeCommand(UsbCommand *command)
 {
+	pthread_mutex_lock(&cmdBufferMutex);
     if( ( cmd_head+1) % CMD_BUFFER_SIZE == cmd_tail)
     {
         //If these two are equal, we're about to overwrite in the
@@ -106,6 +113,7 @@ void storeCommand(UsbCommand *command)
     memcpy(destination, command, sizeof(UsbCommand));
 
     cmd_head = (cmd_head +1) % CMD_BUFFER_SIZE; //increment head and wrap
+	pthread_mutex_unlock(&cmdBufferMutex);
 }
 
 
@@ -116,8 +124,10 @@ void storeCommand(UsbCommand *command)
  */
 int getCommand(UsbCommand* response)
 {
+	pthread_mutex_lock(&cmdBufferMutex);
     //If head == tail, there's nothing to read, or if we just got initialized
     if(cmd_head == cmd_tail){
+		pthread_mutex_unlock(&cmdBufferMutex);
         return 0;
     }
     //Pick out the next unread command
@@ -125,7 +135,7 @@ int getCommand(UsbCommand* response)
     memcpy(response, last_unread, sizeof(UsbCommand));
     //Increment tail - this is a circular buffer, so modulo buffer size
     cmd_tail = (cmd_tail +1 ) % CMD_BUFFER_SIZE;
-
+	pthread_mutex_unlock(&cmdBufferMutex);
     return 1;
 }
 
@@ -147,22 +157,28 @@ bool WaitForResponseTimeoutW(uint32_t cmd, UsbCommand* response, size_t ms_timeo
 		response = &resp;
 	}
 
+	uint64_t start_time = msclock();
+	
 	// Wait until the command is received
-	for(size_t dm_seconds=0; dm_seconds < ms_timeout/10; dm_seconds++) {
+	while (true) {
 		while(getCommand(response)) {
 			if(response->cmd == cmd){
 				return true;
 			}
 		}
-		msleep(10); // XXX ugh
-		if (dm_seconds == 200 && show_warning) { // Two seconds elapsed
+		if (msclock() - start_time > ms_timeout) {
+			break;
+		}
+		if (msclock() - start_time > 2000 && show_warning) {
 			PrintAndLog("Waiting for a response from the proxmark...");
 			PrintAndLog("Don't forget to cancel its operation first by pressing on the button");
+			break;
 		}
 	}
 	return false;
 }
 
+
 bool WaitForResponseTimeout(uint32_t cmd, UsbCommand* response, size_t ms_timeout) {
 	return WaitForResponseTimeoutW(cmd, response, ms_timeout, true);
 }
diff --git a/client/proxmark3.c b/client/proxmark3.c
index d0e68b61..f7a87f6d 100644
--- a/client/proxmark3.c
+++ b/client/proxmark3.c
@@ -73,12 +73,11 @@ static void *uart_receiver(void *targ) {
 
 	while (arg->run) {
 		rxlen = 0;
-		if (uart_receive(sp, prx, sizeof(UsbCommand) - (prx-rx), &rxlen)) {
+		if (uart_receive(sp, prx, sizeof(UsbCommand) - (prx-rx), &rxlen) && rxlen) {
 			prx += rxlen;
 			if (prx-rx < sizeof(UsbCommand)) {
 				continue;
 			}
-			
 			UsbCommandReceived((UsbCommand*)rx);
 		}
 		prx = rx;
diff --git a/uart/uart_win32.c b/uart/uart_win32.c
index af521ead..121b2b51 100644
--- a/uart/uart_win32.c
+++ b/uart/uart_win32.c
@@ -107,15 +107,13 @@ void uart_close(const serial_port sp) {
   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_receive(const serial_port sp, byte_t *pbtRx, size_t pszMaxRxLen, size_t *pszRxLen) {
+  return ReadFile(((serial_port_windows*)sp)->hPort, pbtRx, pszMaxRxLen, (LPDWORD)pszRxLen, NULL);
 }
 
 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);
+  return WriteFile(((serial_port_windows*)sp)->hPort, pbtTx, szTxLen, &dwTxLen, NULL);
 }
 
 bool uart_set_speed(serial_port sp, const uint32_t uiPortSpeed) {
-- 
2.39.2