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 test case was added into mysql.test.

client/my_readline.h:
  Data members error and truncated was added to LINE_BUFFER structure.
  These data members used instead of out parameters in functions
  batch_readline, intern_read_line.
client/mysql.cc:
  read_and_execute() was modified: set status.exit_status to 1
  when the error occured while reading the next command line in
  non-interactive mode. Also the value of the truncated attribute
  of structure LINE_BUFF is taken into account only for non-iteractive mode.
client/readline.cc:
  intern_read_line() was modified: cancel reading from input if
  fill_buffer() returns -1, e.g. if call to read failed.
  batch_readline was modified: set the error data member of LINE_BUFFER
  structure to value of my_errno when system error happened during call
  to my_read/my_realloc.
mysql-test/t/mysql.test:
  Test for bug#57450 was added.

client/my_readline.h

@@ -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);

client/mysql.cc

@@ -1872,14 +1872,13 @@ static int read_and_execute(bool interactive)
   ulong line_number=0;
   bool ml_comment= 0;  
   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);
       /*
         Skip UTF8 Byte Order Marker (BOM) 0xEFBBBF.
         Editors like "notepad" put this marker in
@@ -1953,9 +1952,13 @@ static int read_and_execute(bool interactive)
       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 && status.line_buff->error)
+        status.exit_status= 1;
+      else
+        status.exit_status= 0;
       break;
     }
 
@@ -1976,7 +1979,8 @@ static int read_and_execute(bool interactive)
 #endif
       continue;
     }
-    if (add_line(glob_buffer,line,&in_string,&ml_comment, truncated))
+    if (add_line(glob_buffer, line, &in_string, &ml_comment,
+                 status.line_buff ? status.line_buff->truncated : 0))
       break;
   }
   /* if in batch mode, send last query even if it doesn't end with \g or go */

client/readline.cc

@@ -24,7 +24,7 @@ static bool init_line_buffer(LINE_BUFFER *buffer,File file,ulong size,
 			    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 max_size,FILE *file)
 }
 
 
-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 *buffer)
     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 *buffer)
   /* 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));
 
@@ -198,8 +203,7 @@ static size_t fill_buffer(LINE_BUFFER *buffer)
 }
 
 
-
-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 +218,25 @@ char *intern_read_line(LINE_BUFFER *buffer, ulong *out_length, bool *truncated)
     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);

mysql-test/t/mysql.test

@@ -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 #