Bug #4053: too many of "error 1236: 'binlog truncated in the middle of event' from master"

- Fix my_read/my_write to handle return values from read/write correctly
- Add debugging 'deprecated function' warning to my_lread/my_lwrite
- Add debugging 'error, read/write interrupt not handled' warning to my_quick_read/my_quick_write

There is no test case associated with these changes.  However, this is a conservative change,
and no repeatable test case is available.


mysys/my_lread.c:
  Warn about using deprecated function.
mysys/my_lwrite.c:
  Warn about using deprecated function.
mysys/my_pread.c:
  Handle interrupted read() or write() (EINTR) properly
mysys/my_quick.c:
  Warn about interrupted read() or write(), which is not
  handled by my_quick_read() or my_quick_write().
mysys/my_read.c:
  Handle interrupted read() (EINTR) properly
mysys/my_write.c:
  Handle interrupted write() (EINTR) properly

mysys/my_lread.c

@@ -30,6 +30,8 @@ uint32 my_lread(int Filedes, byte *Buffer, uint32 Count, myf MyFlags)
   DBUG_PRINT("my",("Fd: %d  Buffer: %ld  Count: %ld  MyFlags: %d",
 		   Filedes, Buffer, Count, MyFlags));
 
+  DBUG_PRINT("error", ("Deprecated my_lread() function should not be used."));
+
   /* Temp hack to get count to int32 while read wants int */
   if ((readbytes = (uint32) read(Filedes, Buffer, (uint) Count)) != Count)
   {

mysys/my_lwrite.c

@@ -26,6 +26,8 @@ uint32 my_lwrite(int Filedes, const byte *Buffer, uint32 Count, myf MyFlags)
   DBUG_PRINT("my",("Fd: %d  Buffer: %lx  Count: %ld  MyFlags: %d",
 		   Filedes, Buffer, Count, MyFlags));
 
+  DBUG_PRINT("error", ("Deprecated my_lwrite() function should not be used."));
+
   /* Temp hack to get count to int32 while write wants int */
   if ((writenbytes = (uint32) write(Filedes, Buffer, (uint) Count)) != Count)
   {

mysys/my_pread.c

@@ -52,8 +52,12 @@ uint my_pread(File Filedes, byte *Buffer, uint Count, my_off_t offset,
       DBUG_PRINT("warning",("Read only %ld bytes off %ld from %d, errno: %d",
 			    readbytes,Count,Filedes,my_errno));
 #ifdef THREAD
-      if (readbytes == 0 && errno == EINTR)
+      if ((readbytes == 0 || (int) readbytes == -1) && errno == EINTR)
+      {
+        DBUG_PRINT("debug", ("my_pread() was interrupted and returned %d",
+                             (int) readbytes));
         continue;                              /* Interrupted */
+      }
 #endif
       if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
       {
@@ -124,8 +128,8 @@ uint my_pwrite(int Filedes, const byte *Buffer, uint Count, my_off_t offset,
       VOID(sleep(MY_WAIT_FOR_USER_TO_FIX_PANIC));
       continue;
     }
-    if ((writenbytes == 0 && my_errno == EINTR) ||
+    if ((writenbytes > 0 && (uint) writenbytes != (uint) -1) ||
-	(writenbytes > 0 && (uint) writenbytes != (uint) -1))
+        my_errno == EINTR)
       continue;					/* Retry */
 #endif
     if (MyFlags & (MY_NABP | MY_FNABP))

mysys/my_quick.c

@@ -26,6 +26,14 @@ uint my_quick_read(File Filedes,byte *Buffer,uint Count,myf MyFlags)
 
   if ((readbytes = (uint) read(Filedes, Buffer, Count)) != Count)
   {
+#ifndef DBUG_OFF
+    if ((readbytes == 0 || (int) readbytes == -1) && errno == EINTR)
+    {  
+      DBUG_PRINT("error", ("my_quick_read() was interrupted and returned %d"
+                           ".  This function does not retry the read!",
+                           (int) readbytes));
+    }
+#endif
     my_errno=errno;
     return readbytes;
   }
@@ -35,8 +43,24 @@ uint my_quick_read(File Filedes,byte *Buffer,uint Count,myf MyFlags)
 
 uint my_quick_write(File Filedes,const byte *Buffer,uint Count)
 {
-  if ((uint) write(Filedes,Buffer,Count) != Count)
+#ifndef DBUG_OFF
+  uint writtenbytes;
+#endif
+
+  if ((
+#ifndef DBUG_OFF
+       writtenbytes =
+#endif
+       (uint) write(Filedes,Buffer,Count)) != Count)
   {
+#ifndef DBUG_OFF
+    if ((writtenbytes == 0 || (int) writtenbytes == -1) && errno == EINTR)
+    {  
+      DBUG_PRINT("error", ("my_quick_write() was interrupted and returned %d"
+                           ".  This function does not retry the write!",
+                           (int) writtenbytes));
+    }
+#endif
     my_errno=errno;
     return (uint) -1;
   }

mysys/my_read.c

@@ -51,8 +51,12 @@ uint my_read(File Filedes, byte *Buffer, uint Count, myf MyFlags)
       DBUG_PRINT("warning",("Read only %ld bytes off %ld from %d, errno: %d",
 			    readbytes,Count,Filedes,my_errno));
 #ifdef THREAD
-      if (readbytes == 0 && errno == EINTR)
+      if ((readbytes == 0 || (int) readbytes == -1) && errno == EINTR)
+      {  
+        DBUG_PRINT("debug", ("my_read() was interrupted and returned %d",
+                             (int) readbytes));
         continue;                              /* Interrupted */
+      }
 #endif
       if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
       {

mysys/my_write.c

@@ -57,18 +57,24 @@ uint my_write(int Filedes, const byte *Buffer, uint Count, myf MyFlags)
       VOID(sleep(MY_WAIT_FOR_USER_TO_FIX_PANIC));
       continue;
     }
-    if (!writenbytes)
+
+    if ((writenbytes == 0 || (int) writenbytes == -1))
     {
-      /* We may come here on an interrupt or if the file quote is exeeded */
       if (my_errno == EINTR)
-	continue;
-      if (!errors++)				/* Retry once */
       {
+        DBUG_PRINT("debug", ("my_write() was interrupted and returned %d",
+                             (int) writenbytes));
+        continue;                               /* Interrupted */
+      }
+
+      if (!writenbytes && !errors++)		/* Retry once */
+      {
+        /* We may come here if the file quota is exeeded */
         errno=EFBIG;				/* Assume this is the error */
         continue;
       }
     }
-    else if ((uint) writenbytes != (uint) -1)
+    else
       continue;					/* Retry */
 #endif
     if (MyFlags & (MY_NABP | MY_FNABP))