Fixed bug #29751 - do not rename the error log at FLUSH LOGS.

Added open log file with FILE_SHARE_DELETE flag on Windows.

sql/log.cc:
  added reopen_fstreams();
  modified redirect_std_streams(): call to sequence of freopen()
  replaced to reopen_fstreams();
  modified flush_error_log(): removed file rename for flushed
  error log file.
sql/mysqld.cc:
  modified main() and init_server_components(): do open log error file
  over call to reopen_fstreams().

sql/log.cc

@@ -5063,67 +5063,90 @@ void sql_perror(const char *message)
 }
 
 
+#ifdef __WIN__
+extern "C" my_bool reopen_fstreams(const char *filename,
+                                   FILE *outstream, FILE *errstream)
+{
+  int handle_fd;
+  int stream_fd;
+  HANDLE osfh;
+
+  DBUG_ASSERT(filename && (outstream || errstream));
+
+  if ((osfh= CreateFile(filename, GENERIC_READ | GENERIC_WRITE,
+                        FILE_SHARE_READ | FILE_SHARE_WRITE |
+                        FILE_SHARE_DELETE, NULL,
+                        OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL,
+                        NULL)) == INVALID_HANDLE_VALUE)
+    return TRUE;
+
+  if ((handle_fd= _open_osfhandle((intptr_t)osfh,
+                                  _O_APPEND | _O_TEXT)) == -1)
+  {
+    CloseHandle(osfh);
+    return TRUE;
+  }
+
+  if (outstream)
+  {
+    stream_fd= _fileno(outstream);
+    if (_dup2(handle_fd, stream_fd) < 0)
+    {
+      CloseHandle(osfh);
+      return TRUE;
+    }
+  }
+
+  if (errstream)
+  {
+    stream_fd= _fileno(errstream);
+    if (_dup2(handle_fd, stream_fd) < 0)
+    {
+      CloseHandle(osfh);
+      return TRUE;
+    }
+  }
+
+  _close(handle_fd);
+  return FALSE;
+}
+#else
+extern "C" my_bool reopen_fstreams(const char *filename,
+                                   FILE *outstream, FILE *errstream)
+{
+  if (outstream && !freopen(filename, "a+", outstream))
+    return TRUE;
+
+  if (errstream && !freopen(filename, "a+", errstream))
+    return TRUE;
+
+  return FALSE;
+}
+#endif
+
+
 /*
   Unfortunately, there seems to be no good way
   to restore the original streams upon failure.
 */
 static bool redirect_std_streams(const char *file)
 {
-  if (freopen(file, "a+", stdout) && freopen(file, "a+", stderr))
-  {
+  if (reopen_fstreams(file, stdout, stderr))
+    return TRUE;
+
   setbuf(stderr, NULL);
   return FALSE;
-  }
-
-  return TRUE;
 }
 
 
 bool flush_error_log()
 {
-  bool result=0;
+  bool result= 0;
   if (opt_error_log)
   {
-    char err_renamed[FN_REFLEN], *end;
-    end= strmake(err_renamed,log_error_file,FN_REFLEN-5);
-    strmov(end, "-old");
     VOID(pthread_mutex_lock(&LOCK_error_log));
-#ifdef __WIN__
-    char err_temp[FN_REFLEN+5];
-    /*
-     On Windows is necessary a temporary file for to rename
-     the current error file.
-    */
-    strxmov(err_temp, err_renamed,"-tmp",NullS);
-    (void) my_delete(err_temp, MYF(0)); 
-    if (freopen(err_temp,"a+",stdout))
-    {
-      int fd;
-      size_t bytes;
-      uchar buf[IO_SIZE];
-
-      freopen(err_temp,"a+",stderr);
-      setbuf(stderr, NULL);
-      (void) my_delete(err_renamed, MYF(0));
-      my_rename(log_error_file,err_renamed,MYF(0));
-      redirect_std_streams(log_error_file);
-
-      if ((fd = my_open(err_temp, O_RDONLY, MYF(0))) >= 0)
-      {
-        while ((bytes= my_read(fd, buf, IO_SIZE, MYF(0))) &&
-               bytes != MY_FILE_ERROR)
-          my_fwrite(stderr, buf, bytes, MYF(0));
-        my_close(fd, MYF(0));
-      }
-      (void) my_delete(err_temp, MYF(0)); 
-    }
-    else
-     result= 1;
-#else
-   my_rename(log_error_file,err_renamed,MYF(0));
     if (redirect_std_streams(log_error_file))
       result= 1;
-#endif
     VOID(pthread_mutex_unlock(&LOCK_error_log));
   }
   return result;

sql/mysqld.cc

@@ -199,6 +199,9 @@ typedef fp_except fp_except_t;
 # endif
 #endif
 
+extern "C" my_bool reopen_fstreams(const char *filename,
+                                   FILE *outstream, FILE *errstream);
+
 inline void setup_fpu()
 {
 #if defined(__FreeBSD__) && defined(HAVE_IEEEFP_H)
@@ -3821,15 +3824,17 @@ static int init_server_components()
       opt_error_log= 1;				// Too long file name
     else
     {
+      my_bool res;
 #ifndef EMBEDDED_LIBRARY
-      if (freopen(log_error_file, "a+", stdout))
+      res= reopen_fstreams(log_error_file, stdout, stderr);
+#else
+      res= reopen_fstreams(log_error_file, NULL, stderr);
 #endif
-      {
-        if (freopen(log_error_file, "a+", stderr))
+
+      if (!res)
         setbuf(stderr, NULL);
     }
   }
-  }
 
   if (xid_cache_init())
   {
@@ -4475,8 +4480,8 @@ we force server id to 2, but this MySQL server will not act as a slave.");
 #ifdef __WIN__
   if (!opt_console)
   {
-    freopen(log_error_file,"a+",stdout);
-    freopen(log_error_file,"a+",stderr);
+    if (reopen_fstreams(log_error_file, stdout, stderr))
+      unireg_abort(1);
     setbuf(stderr, NULL);
     FreeConsole();				// Remove window
   }