From: Sergey Vojtovich
Date: December 7 2010 1:45pm
Subject: Re: bzr commit into mysql-5.1-bugteam branch (Dmitry.Shulga:3521)
 Bug#57450
List-Archive: http://lists.mysql.com/commits/126204
Message-Id: <20101207134516.GA30678@june>
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Hi Dmitry,

a few questions inline...

On Fri, Dec 03, 2010 at 11:49:46AM +0000, Dmitry Shulga wrote:
> #At file:///Users/shulga/projects/mysql/5.1-bugteam-bug57450/ based on revid:azundris@stripped
> 
>  3521 Dmitry Shulga	2010-12-03
>       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 for type of input source.
>       
>       The solution is to check if stdin's file descriptor related to directory
>       and exit from program if this case is true.
>      @ client/readline.cc
>         batch_readline_init() was modified: added checking for file mode
>         and returning from function if input stream is a directory.
>         
>         fill_buffer() and intern_read_line() was modified: doesn't set eof flag
>         if read failed with temporal error and try repeat this failed syscall.
> 
>     modified:
>       client/readline.cc
> === modified file 'client/readline.cc'
> --- a/client/readline.cc	2009-03-18 08:27:49 +0000
> +++ b/client/readline.cc	2010-12-03 11:49:35 +0000
> @@ -18,6 +18,7 @@
>  #include <my_global.h>
>  #include <my_sys.h>
>  #include <m_string.h>
> +#include <my_dir.h>
>  #include "my_readline.h"
>  
>  static bool init_line_buffer(LINE_BUFFER *buffer,File file,ulong size,
> @@ -30,6 +31,15 @@ static char *intern_read_line(LINE_BUFFE
>  LINE_BUFFER *batch_readline_init(ulong max_size,FILE *file)
>  {
>    LINE_BUFFER *line_buff;
> +  MY_STAT input_file_stat;
> +  int input_fd;
> +
> +  input_fd= fileno(file);
> +
> +  if (my_fstat(input_fd, &input_file_stat, MYF(0)) ||
> +      (input_file_stat.st_mode & S_IFDIR))
Why not MY_S_ISDIR(input_file_stat.st_mode)?
Or at least not (input_file_stat.st_mode & MY_S_IFDIR)?
What if I run "mysql > abc", or in other words what if
input_fd is a tty?

> +    return 0;
> +
>    if (!(line_buff=(LINE_BUFFER*)
>          my_malloc(sizeof(*line_buff),MYF(MY_WME | MY_ZEROFILL))))
>      return 0;
> @@ -177,8 +187,15 @@ 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)
> +  {
> +    /*
> +      we don't set eof flag for this temporal errors because next
> +      call to read may be successful.
> +    */
> +    if (errno != EAGAIN && errno != EINTR)
Why not my_errno?
Why at all to change this code? As far as I can see my_read() handles EINTR.

> +      buffer->eof= 1;
>      return (size_t) -1;
> -
> +  }
>    DBUG_PRINT("fill_buff", ("Got %lu bytes", (ulong) read_count));
>  
>    if (!read_count)
> @@ -222,6 +239,9 @@ char *intern_read_line(LINE_BUFFER *buff
>        {
>          if (buffer->eof)
>            DBUG_RETURN(0);
> +        // check if syscall read failed with temporal error.
> +        else if (length == (uint) -1)
> +          continue;
Don't you consider this way of returning "temporal error" too complex?

>        }
>        else
>          continue;
> 

Regards,
Sergey
-- 
Sergey Vojtovich <svoj@stripped>
MySQL AB, Software Engineer
Izhevsk, Russia, www.mysql.com