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 #define ENOMEM 12
  27
  28 static int my_id;
  29
  30 STATE(enomem);
  31 STATE(ok);
  32
  33 static void ok_to_use(struct sm_state *sm, struct expression *mod_expr)
  34 {
  35         if (sm->state != &ok)
  36                 set_state(my_id, sm->name, sm->sym, &ok);
  37 }
  38
  39 static void allocation_succeeded(const char *fn, struct expression *call_expr,
  40                                 struct expression *assign_expr, void *unused)
  41 {
  42         set_state_expr(my_id, assign_expr->left, &ok);
  43 }
  44
  45 static void allocation_failed(const char *fn, struct expression *call_expr,
  46                         struct expression *assign_expr, void *_arg_no)
  47 {
  48         set_state_expr(my_id, assign_expr->left, &enomem);
  49 }
  50
  51 static void match_return(struct expression *ret_value)
  52 {
  53         struct sm_state *sm;
  54         struct state_list *slist;
  55         sval_t sval;
  56
  57         if (!ret_value)
  58                 return;
  59         if (returns_unsigned(cur_func_sym))
  60                 return;
  61         if (returns_pointer(cur_func_sym))
  62                 return;
  63         if (!get_value(ret_value, &sval) || sval.value != -1)
  64                 return;
  65         if (get_macro_name(ret_value->pos))
  66                 return;
  67
  68         slist = get_all_states(my_id);
  69
  70         FOR_EACH_PTR(slist, sm) {
  71                 if (sm->state == &enomem) {
  72                         sm_msg("warn: returning -1 instead of -ENOMEM is sloppy");
  73                         goto out;
  74                 }
  75         } END_FOR_EACH_PTR(sm);
  76
  77 out:
  78         free_slist(&slist);
  79 }
  80
  81 void check_return_enomem(int id)
  82 {
  83         if (option_project != PROJ_KERNEL)
  84                 return;
  85
  86         my_id = id;
  87         return_implies_state("kmalloc", valid_ptr_min, valid_ptr_max, &allocation_succeeded, INT_PTR(0));
  88         return_implies_state("kmalloc", 0, 0, &allocation_failed, INT_PTR(0));
  89         return_implies_state("kzalloc", valid_ptr_min, valid_ptr_max, &allocation_succeeded, INT_PTR(0));
  90         return_implies_state("kzalloc", 0, 0, &allocation_failed, INT_PTR(0));
  91         return_implies_state("kcalloc", valid_ptr_min, valid_ptr_max, &allocation_succeeded, INT_PTR(0));
  92         return_implies_state("kcalloc", 0, 0, &allocation_failed, INT_PTR(0));
  93         add_hook(&match_return, RETURN_HOOK);
  94         add_modification_hook(my_id, &ok_to_use);
  95 }