check_frees_argument.c

   1 /*
   2  * sparse/check_frees_argument.c
   3  *
   4  * Copyright (C) 2009 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * This script is for finding functions like hcd_buffer_free() which free
  12  * their arguments.  After running it, add those functions to check_memory.c
  13  */
  14
  15 #include "smatch.h"
  16 #include "smatch_slist.h"
  17
  18 static int my_id;
  19
  20 STATE(freed);
  21
  22 static struct symbol *this_func;
  23 static struct tracker_list *freed_args = NULL;
  24
  25 static void match_function_def(struct symbol *sym)
  26 {
  27         this_func = sym;
  28 }
  29
  30 static int is_arg(char *name, struct symbol *sym)
  31 {
  32         struct symbol *arg;
  33         const char *arg_name;
  34
  35         FOR_EACH_PTR(this_func->ctype.base_type->arguments, arg) {
  36                 arg_name = (arg->ident?arg->ident->name:"-");
  37                 if (sym == arg && !strcmp(name, arg_name))
  38                         return 1;
  39         } END_FOR_EACH_PTR(arg);
  40         return 0;
  41 }
  42
  43 static void match_kfree(const char *fn, struct expression *expr, void *data)
  44 {
  45         struct expression *tmp;
  46         struct symbol *sym;
  47         char *name;
  48
  49         tmp = get_argument_from_call_expr(expr->args, 0);
  50         tmp = strip_expr(tmp);
  51         name = get_variable_from_expr(tmp, &sym);
  52         if (is_arg(name, sym)) {
  53                 set_state(name, my_id, sym, &freed);
  54         }
  55 }
  56
  57 static int return_count = 0;
  58 static void match_return(struct statement *stmt)
  59 {
  60         struct state_list *slist;
  61         struct sm_state *tmp;
  62         struct tracker *tracker;
  63
  64         if (!return_count) {
  65                 slist = get_all_states(my_id);
  66                 FOR_EACH_PTR(slist, tmp) {
  67                         if (tmp->state == &freed)
  68                                 add_tracker(&freed_args, tmp->name, my_id,
  69                                             tmp->sym);
  70                 } END_FOR_EACH_PTR(tmp);
  71                 free_slist(&slist);
  72         } else {
  73                 FOR_EACH_PTR(freed_args, tracker) {
  74                         tmp = get_sm_state(tracker->name, my_id, tracker->sym);
  75                         if (tmp && tmp->state != &freed)
  76                                 del_tracker(&freed_args, tracker->name, my_id,
  77                                             tracker->sym);
  78                 } END_FOR_EACH_PTR(tracker);
  79
  80         }
  81 }
  82
  83 static void print_arg(struct symbol *sym)
  84 {
  85         struct symbol *arg;
  86         int i = 0;
  87
  88         FOR_EACH_PTR(this_func->ctype.base_type->arguments, arg) {
  89                 if (sym == arg) {
  90                         printf("info: free_arg %s %d\n", get_function(), i);
  91                         return;
  92                 }
  93                 i++;
  94         } END_FOR_EACH_PTR(arg);
  95 }
  96
  97 static void match_end_func(struct symbol *sym)
  98 {
  99         struct tracker *tracker;
 100
 101         if (is_reachable())
 102                 match_return(NULL);
 103
 104         FOR_EACH_PTR(freed_args, tracker) {
 105                 print_arg(tracker->sym);
 106         } END_FOR_EACH_PTR(tracker);
 107
 108         free_trackers_and_list(&freed_args);
 109         return_count = 0;
 110 }
 111
 112 void check_frees_argument(int id)
 113 {
 114         my_id = id;
 115         add_hook(&match_function_def, FUNC_DEF_HOOK);
 116         add_function_hook("kfree", &match_kfree, NULL);
 117         add_hook(&match_return, RETURN_HOOK);
 118         add_hook(&match_end_func, END_FUNC_HOOK);
 119 }