[GRASS-dev] Re: [GRASS GIS] #461: v.to.db crashes on a shapefile connected with v.external

[GRASS GIS]

#461: v.to.db crashes on a shapefile connected with v.external
-----------------------+----------------------------------------------------
  Reporter:  msieczka  |       Owner:  grass-dev at lists.osgeo.org
      Type:  defect    |      Status:  new                      
  Priority:  critical  |   Milestone:  6.4.0                    
 Component:  Vector    |     Version:  svn-develbranch6         
Resolution:            |    Keywords:                           
  Platform:  Linux     |         Cpu:  x86-64                   
-----------------------+----------------------------------------------------
Comment (by mmetz):

 Replying to [comment:8 mmetz]:
 >
 > Going a bit further to the root of the problem: in this case const char
 *col passed to db_select_int() in lib/db/dbmi_client/select.c is a zero
 length string, you could do for 'col' the same test that's done for
 'where' and exit with an error.

 The following patch works for me

 {{{
 Index: select.c
 ===================================================================
 --- select.c    (revision 40416)
 +++ select.c    (working copy)
 @@ -115,6 +115,9 @@

      G_debug(3, "db_select_int()");

 +    if (col == NULL || strlen(col) == 0)
 +       G_fatal_error(_("Missing column name"));
 +
      /* allocate */
      alloc = 1000;
      val = (int *)G_malloc(alloc * sizeof(int));
 @@ -203,6 +206,12 @@
      dbValue *value;
      dbTable *table;

 +    if (key == NULL || strlen(key) == 0)
 +       G_fatal_error(_("Missing key column name"));
 +
 +    if (col == NULL || strlen(col) == 0)
 +       G_fatal_error(_("Missing column name"));
 +
      G_zero(val, sizeof(dbValue));
      sprintf(buf, "SELECT %s FROM %s WHERE %s = %d\n", col, tab, key, id);
      db_init_string(&stmt);
 @@ -259,6 +268,12 @@

      G_debug(3, "db_select_db_select_CatValArray ()");

 +    if (key == NULL || strlen(key) == 0)
 +       G_fatal_error(_("Missing key column name"));
 +
 +    if (col == NULL || strlen(col) == 0)
 +       G_fatal_error(_("Missing column name"));
 +
      db_init_string(&stmt);

      sprintf(buf, "SELECT %s, %s FROM %s", key, col, tab);
 }}}

 Problem is when a module gives a broken sql string to
 db_execute_immediate(), hopefully that aborts with an error and not a
 segfault.

 Glynn's patch could be useful in other circumstances too.

 Markus M

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/461#comment:9>
GRASS GIS <http://grass.osgeo.org>