Hi Dmitry,
On Wed, Dec 08, 2010 at 09:42:59AM +0000, Dmitry Shulga wrote:
> #At file:///Users/shulga/projects/mysql/5.1-bugteam-bug57450/ based on
> revid:azundris@stripped
>
> 3521 Dmitry Shulga 2010-12-08
> 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 2010-12-08 09:42:55 +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 +31,12 @@ 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;
> +
> + if (my_fstat(fileno(file), &input_file_stat, MYF(0)) ||
> + !(input_file_stat.st_mode & (MY_S_IFREG|MY_S_IFIFO)))
> + return 0;
> +
I asked: "What if I run "mysql > abc", or in other words what if
input_fd is a tty?"
You answered: "Fixed."
But my question still applies. Let me try to ask it differently.
What if I run my_fstat() on unnamed fd (e.g. tty, socket, unnamed
pipe)?
> if (!(line_buff=(LINE_BUFFER*)
> my_malloc(sizeof(*line_buff),MYF(MY_WME | MY_ZEROFILL))))
> return 0;
> @@ -177,8 +184,15 @@ 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 (my_errno != EAGAIN && my_errno != EINTR)
> + buffer->eof= 1;
> return (size_t) -1;
Thanks for your explanations. Now I better understand what you're
trying to achieve here.
I'd suggest to study:
http://lists.mysql.com/commits/69536
If you see no problems with that patch, let me study it once again.
As far as I can see the problem you're trying to hide here is a
regression caused by that bugfix.
Regards,
Sergey
> -
> + }
> DBUG_PRINT("fill_buff", ("Got %lu bytes", (ulong) read_count));
>
> if (!read_count)
> @@ -222,6 +236,9 @@ 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;
> }
> else
> continue;
>
--
Sergey Vojtovich <svoj@stripped>
MySQL AB, Software Engineer
Izhevsk, Russia, www.mysql.com
