patch graphlcd-base port.c to protect access to port

patch graphlcd-base port.c to protect access to port.diff

diff -Naur graphlcd-base-9999_orig/glcddrivers/noritake800.c graphlcd-base-9999/glcddrivers/noritake800.c
--- graphlcd-base-9999_orig/glcddrivers/noritake800.c	2012-11-15 00:07:15.000000000 +0100
+++ graphlcd-base-9999/glcddrivers/noritake800.c	2012-11-15 00:08:52.604326957 +0100
@@ -244,19 +244,25 @@
     {
         // use DirectIO
         if (m_pport->Open(config->port) != 0)
+        {
+            syslog(LOG_ERR, "%s: INFO: cannot open configured port %x,  Err: %s (cDriverNoritake800::Init)\n", config->name.c_str(), config->port, strerror(errno));
             return -1;
+        }
         uSleep(10);
     }
     else
     {
         // use ppdev
         if (m_pport->Open(config->device.c_str()) != 0)
+        {
+            syslog(LOG_ERR, "%s: INFO: cannot open configured device %s,  Err: %s (cDriverNoritake800::Init)\n", config->name.c_str(), config->device.c_str(), strerror(errno));
             return -1;
+        }
     }
 
     if (nSleepInit() != 0)
     {
-        syslog(LOG_ERR, "%s: INFO: cannot change wait parameters  Err: %s (cDriver::Init)\n", config->name.c_str(), strerror(errno));
+        syslog(LOG_ERR, "%s: INFO: cannot change wait parameters  Err: %s (cDriverNoritake800::Init)\n", config->name.c_str(), strerror(errno));
         m_bSleepIsInit = false;
     }
     else
@@ -265,7 +271,11 @@
     }
 
     // benchmark port access
-    m_pport->Claim();
+    if (!m_pport->Claim())
+    {
+        syslog(LOG_ERR, "%s: INFO: cannot claim port  Err: %s (cDriverNoritake800::Init)\n", config->name.c_str(), strerror(errno));
+        return -1;
+    }
     syslog(LOG_DEBUG, "%s: benchmark started.\n", config->name.c_str());
     gettimeofday(&tv1, 0);
     int nBenchIterations = 10000;
@@ -338,29 +348,31 @@
             refreshAll = true;
     }
 
-    m_pport->Claim();
-    for (xb = 0; xb < width; ++xb)
+    if (m_pport->Claim())
     {
-        for (yb = 0; yb < m_iSizeYb; ++yb)
+        for (xb = 0; xb < width; ++xb)
         {
-            // if differenet or explicitly refresh all
-            if (    m_pVFDMem[xb][yb] != m_pDrawMem[xb][yb] ||
-                    refreshAll )
+            for (yb = 0; yb < m_iSizeYb; ++yb)
             {
-                m_pVFDMem[xb][yb] = m_pDrawMem[xb][yb];
-                // reset RefreshCounter if doing a full refresh
-                if (refreshAll)
-                    m_nRefreshCounter = 0;
-                // actually write to display
-                N800WriteByte(
-                    (m_pVFDMem[xb][yb]) ^ ((config->invert != 0) ? 0xff : 0x00),
-                    xb,
-                    yb,
-                    0);
+                // if differenet or explicitly refresh all
+                if (    m_pVFDMem[xb][yb] != m_pDrawMem[xb][yb] ||
+                        refreshAll )
+                {
+                    m_pVFDMem[xb][yb] = m_pDrawMem[xb][yb];
+                    // reset RefreshCounter if doing a full refresh
+                    if (refreshAll)
+                        m_nRefreshCounter = 0;
+                    // actually write to display
+                    N800WriteByte(
+                        (m_pVFDMem[xb][yb]) ^ ((config->invert != 0) ? 0xff : 0x00),
+                        xb,
+                        yb,
+                        0);
+                }
             }
         }
+        m_pport->Release();
     }
-    m_pport->Release();
 }
 
 void cDriverNoritake800::N800Cmd(unsigned char data)
@@ -458,9 +470,11 @@
     }
     unsigned int darkness = 16 - (unsigned int)((double)percent * 16.0 / 100.0);
 
-    m_pport->Claim();
-    N800Cmd(0x40 + (darkness & 0xf));
-    m_pport->Release();
+    if (m_pport->Claim())
+    {
+        N800Cmd(0x40 + (darkness & 0xf));
+        m_pport->Release();
+    }
 }
 
 unsigned char cDriverNoritake800::N800LptWiringMask(unsigned char ctrl_bits)
diff -Naur graphlcd-base-9999_orig/glcddrivers/port.c graphlcd-base-9999/glcddrivers/port.c
--- graphlcd-base-9999_orig/glcddrivers/port.c	2012-11-15 00:07:15.000000000 +0100
+++ graphlcd-base-9999/glcddrivers/port.c	2012-11-15 00:07:34.946321677 +0100
@@ -17,6 +17,7 @@
 #include <syslog.h>
 #include <unistd.h>
 #include <termios.h>
+#include <pthread.h>
 #include <sys/io.h>
 #include <sys/ioctl.h>
 #include <linux/ppdev.h>
@@ -33,6 +34,8 @@
 namespace GLCD
 {
 
+static pthread_mutex_t claimport_mutex;
+
 static inline int port_in(int port)
 {
 #ifdef __HAS_DIRECTIO__
@@ -168,16 +171,20 @@
     return 0;
 }
 
-void cParallelPort::Claim()
+bool cParallelPort::Claim()
 {
     if (usePPDev)
-        ioctl(fd, PPCLAIM);
+        return (ioctl(fd, PPCLAIM) == 0);
+    else
+        return (pthread_mutex_lock(&claimport_mutex) == 0);
 }
 
 void cParallelPort::Release()
 {
     if (usePPDev)
         ioctl(fd, PPRELEASE);
+    else
+        pthread_mutex_unlock(&claimport_mutex);
 }
 
 void cParallelPort::SetDirection(int direction)
diff -Naur graphlcd-base-9999_orig/glcddrivers/port.h graphlcd-base-9999/glcddrivers/port.h
--- graphlcd-base-9999_orig/glcddrivers/port.h	2012-11-15 00:07:15.000000000 +0100
+++ graphlcd-base-9999/glcddrivers/port.h	2012-11-15 00:07:34.947321678 +0100
@@ -45,7 +45,7 @@
     bool IsDirectIO() const { return (!usePPDev); }
     int GetPortHandle() const { return ((usePPDev) ? fd : port); }
 
-    void Claim();
+    bool Claim();
     void Release();
 
     void SetDirection(int direction);