check_return_enomem.c

   1 /*
   2  * Copyright (C) 2010 Dan Carpenter.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 /*
  19  * Complains about places that return -1 instead of -ENOMEM
  20  */
  21
  22 #include "smatch.h"
  23 #include "smatch_slist.h"
  24 #include "smatch_extra.h"
  25
  26 static int my_id;
  27
  28 static void match_return(struct expression *ret_value)
  29 {
  30         struct expression *expr;
  31         struct sm_state *sm;
  32         struct stree *stree;
  33         sval_t sval;
  34
  35         if (!ret_value)
  36                 return;
  37         if (returns_unsigned(cur_func_sym))
  38                 return;
  39         if (returns_pointer(cur_func_sym))
  40                 return;
  41         if (!get_value(ret_value, &sval) || sval.value != -1)
  42                 return;
  43         if (get_macro_name(ret_value->pos))
  44                 return;
  45
  46         stree = __get_cur_stree();
  47
  48         FOR_EACH_MY_SM(SMATCH_EXTRA, stree, sm) {
  49                 if (!estate_get_single_value(sm->state, &sval) || sval.value != 0)
  50                         continue;
  51                 expr = get_assigned_expr_name_sym(sm->name, sm->sym);
  52                 if (!expr)
  53                         continue;
  54                 if (expr->type != EXPR_CALL || expr->fn->type != EXPR_SYMBOL)
  55                         continue;
  56                 if (!expr->fn->symbol_name)
  57                         continue;
  58                 /* To be honest the correct check is:
  59                  * if (strstr(expr->fn->symbol_name->name, "alloc"))
  60                  *      complain();
  61                  * But it generates too many warnings and it's too depressing.
  62                  */
  63                 if (strcmp(expr->fn->symbol_name->name, "kmalloc") != 0 &&
  64                     strcmp(expr->fn->symbol_name->name, "kzalloc") != 0)
  65                         continue;
  66
  67                 sm_warning("returning -1 instead of -ENOMEM is sloppy");
  68                 return;
  69
  70         } END_FOR_EACH_SM(sm);
  71 }
  72
  73 void check_return_enomem(int id)
  74 {
  75         if (option_project != PROJ_KERNEL)
  76                 return;
  77
  78         my_id = id;
  79         add_hook(&match_return, RETURN_HOOK);
  80 }