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From:Davi Arnaut Date:January 17 2011 9:18am
Subject:Re: bzr commit into mysql-5.1-bugteam branch (Dmitry.Shulga:3521)
Bug#57450
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Hi Dmitry,

On 1/12/11 2:13 PM, Dmitry Shulga wrote:
> #At file:///Users/shulga/projects/mysql/5.1-bugteam-bug57450/ based on
> revid:azundris@stripped
>
>   3521 Dmitry Shulga	2011-01-12
>        Fixed bug#57450	- mysql client enter in an infinite loop
>        if the standard input is a directory.
>
>        The problem is that mysql monitor try to read from stdin without
>        checking input source type.
>
>        The solution is to stop reading data from standard input if a call
>        to read(2) failed.
>
>        A new output parameter was introduced into functions batch_readline()
>        and intern_read_line() in order to differentiate between
>        cases of getting EOF and getting error on standard input.
>

The error handling looks good so far, but I particularly don't like how 
the error and EOF states are being passed. I prefer the state (EOF and 
error) to be associated with the buffer. The attached patch implements 
this approach.

Regards,

Davi


=== modified file 'client/my_readline.h'
--- client/my_readline.h	2009-03-18 08:27:49 +0000
+++ client/my_readline.h	2011-01-16 23:05:57 +0000
@@ -25,9 +25,11 @@ typedef struct st_line_buffer
   uint eof;
   ulong max_size;
   ulong read_length;		/* Length of last read string */
+  int error;
+  bool truncated;
 } LINE_BUFFER;
 
 extern LINE_BUFFER *batch_readline_init(ulong max_size,FILE *file);
 extern LINE_BUFFER *batch_readline_command(LINE_BUFFER *buffer, char * str);
-extern char *batch_readline(LINE_BUFFER *buffer, bool *truncated);
+extern char *batch_readline(LINE_BUFFER *buffer);
 extern void batch_readline_end(LINE_BUFFER *buffer);

=== modified file 'client/mysql.cc'
--- client/mysql.cc	2010-11-26 13:57:59 +0000
+++ client/mysql.cc	2011-01-16 23:23:27 +0000
@@ -1874,12 +1874,13 @@ static int read_and_execute(bool interac
   COMMANDS *com;
   bool truncated= 0;
   status.exit_status=1;
-  
+
   for (;;)
   {
     if (!interactive)
     {
-      line=batch_readline(status.line_buff, &truncated);
+      line= batch_readline(status.line_buff);
+      truncated= status.line_buff->truncated;
       /*
         Skip UTF8 Byte Order Marker (BOM) 0xEFBBBF.
         Editors like "notepad" put this marker in
@@ -1953,9 +1954,13 @@ static int read_and_execute(bool interac
       if (opt_outfile && line)
 	fprintf(OUTFILE, "%s\n", line);
     }
-    if (!line)					// End of file
+    // End of file or system error
+    if (!line)
     {
-      status.exit_status=0;
+      if (status.line_buff->error)
+        status.exit_status= 1;
+      else
+        status.exit_status= 0;
       break;
     }
 

=== modified file 'client/readline.cc'
--- client/readline.cc	2009-03-18 08:27:49 +0000
+++ client/readline.cc	2011-01-16 22:54:16 +0000
@@ -24,7 +24,7 @@ static bool init_line_buffer(LINE_BUFFER
 			    ulong max_size);
 static bool init_line_buffer_from_string(LINE_BUFFER *buffer,char * str);
 static size_t fill_buffer(LINE_BUFFER *buffer);
-static char *intern_read_line(LINE_BUFFER *buffer, ulong *out_length, bool *truncated);
+static char *intern_read_line(LINE_BUFFER *buffer, ulong *out_length);
 
 
 LINE_BUFFER *batch_readline_init(ulong max_size,FILE *file)
@@ -42,13 +42,12 @@ LINE_BUFFER *batch_readline_init(ulong m
 }
 
 
-char *batch_readline(LINE_BUFFER *line_buff, bool *truncated)
+char *batch_readline(LINE_BUFFER *line_buff)
 {
   char *pos;
   ulong out_length;
-  DBUG_ASSERT(truncated != NULL);
 
-  if (!(pos=intern_read_line(line_buff,&out_length, truncated)))
+  if (!(pos= intern_read_line(line_buff, &out_length)))
     return 0;
   if (out_length && pos[out_length-1] == '\n')
     if (--out_length && pos[out_length-1] == '\r')  /* Remove '\n' */
@@ -162,7 +161,10 @@ static size_t fill_buffer(LINE_BUFFER *b
     if (!(buffer->buffer = (char*) my_realloc(buffer->buffer,
 					      buffer->bufread+1,
 					      MYF(MY_WME | MY_FAE))))
-      return (uint) -1;
+    {
+      buffer->error= my_errno;
+      return (size_t) -1;
+    }
     buffer->start_of_line=buffer->buffer+start_offset;
     buffer->end=buffer->buffer+bufbytes;
   }
@@ -177,7 +179,10 @@ static size_t fill_buffer(LINE_BUFFER *b
   /* Read in new stuff. */
   if ((read_count= my_read(buffer->file, (uchar*) buffer->end, read_count,
 			   MYF(MY_WME))) == MY_FILE_ERROR)
+  {
+    buffer->error= my_errno;
     return (size_t) -1;
+  }
 
   DBUG_PRINT("fill_buff", ("Got %lu bytes", (ulong) read_count));
 
@@ -199,7 +204,7 @@ static size_t fill_buffer(LINE_BUFFER *b
 
 
 
-char *intern_read_line(LINE_BUFFER *buffer, ulong *out_length, bool *truncated)
+char *intern_read_line(LINE_BUFFER *buffer, ulong *out_length)
 {
   char *pos;
   size_t length;
@@ -214,22 +219,25 @@ char *intern_read_line(LINE_BUFFER *buff
     if (pos == buffer->end)
     {
       /*
-        fill_buffer() can return 0 either on EOF in which case we abort
-        or when the internal buffer has hit the size limit. In the latter case
-        return what we have read so far and signal string truncation.
+        fill_buffer() can return NULL on EOF (in which case we abort),
+        on error, or when the internal buffer has hit the size limit.
+        In the latter case return what we have read so far and signal
+        string truncation.
       */
-      if (!(length=fill_buffer(buffer)) || length == (uint) -1)
+      if (!(length= fill_buffer(buffer)))
       {
         if (buffer->eof)
           DBUG_RETURN(0);
       }
+      else if (length == (size_t) -1)
+        DBUG_RETURN(NULL);
       else
         continue;
       pos--;					/* break line here */
-      *truncated= 1;
+      buffer->truncated= 1;
     }
     else
-      *truncated= 0;
+      buffer->truncated= 0;
     buffer->end_of_line=pos+1;
     *out_length=(ulong) (pos + 1 - buffer->eof - buffer->start_of_line);
     DBUG_RETURN(buffer->start_of_line);

=== modified file 'mysql-test/t/mysql.test'
--- mysql-test/t/mysql.test	2010-12-01 06:55:31 +0000
+++ mysql-test/t/mysql.test	2011-01-16 22:37:34 +0000
@@ -412,6 +412,12 @@ drop table t1;
 --echo
 --exec $MYSQL --skip-column-names --vertical test -e "select 1 as a"
 
+#
+# Bug#57450: mysql client enter in an infinite loop if the standard input is a directory
+#
+--error 1
+--exec $MYSQL < .
+
 --echo
 
 --echo #



Thread
bzr commit into mysql-5.1-bugteam branch (Dmitry.Shulga:3521) Bug#57450Dmitry Shulga12 Jan
  • Re: bzr commit into mysql-5.1-bugteam branch (Dmitry.Shulga:3521)Bug#57450Davi Arnaut17 Jan
    • Re: bzr commit into mysql-5.1-bugteam branch (Dmitry.Shulga:3521) Bug#57450Dmitry Shulga19 Jan