smatch_param_set.c

   1 /*
   2  * sparse/smatch_param_set.c
   3  *
   4  * Copyright (C) 2012 Oracle.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * This is for functions like:
  12  *
  13  * int foo(int *x)
  14  * {
  15  *      if (*x == 42) {
  16  *              *x = 0;
  17  *              return 1;
  18  *      }
  19  *      return 0;
  20  * }
  21  *
  22  * If we return 1 that means the value of *x has been set to 0.  If we return
  23  * 0 then we have left *x alone.
  24  *
  25  */
  26
  27 #include "scope.h"
  28 #include "smatch.h"
  29 #include "smatch_slist.h"
  30 #include "smatch_extra.h"
  31
  32 static int my_id;
  33
  34 static struct smatch_state *unmatched_state(struct sm_state *sm)
  35 {
  36         return alloc_estate_empty();
  37 }
  38
  39 static void extra_mod_hook(const char *name, struct symbol *sym, struct smatch_state *state)
  40 {
  41         set_state(my_id, name, sym, state);
  42 }
  43
  44 static const char *get_param_name(struct sm_state *sm)
  45 {
  46         char *param_name;
  47         int name_len;
  48         static char buf[256];
  49
  50         param_name = sm->sym->ident->name;
  51         name_len = strlen(param_name);
  52
  53         if (sm->name[name_len] == '-' && /* check for '-' from "->" */
  54             strncmp(sm->name, param_name, name_len) == 0) {
  55                 snprintf(buf, sizeof(buf), "$$%s", sm->name + name_len);
  56                 return buf;
  57         } else if (sm->name[0] == '*' && strcmp(sm->name + 1, param_name) == 0) {
  58                 return "*$$";
  59         }
  60         return NULL;
  61 }
  62
  63 static void print_one_return_value_param(int return_id, char *return_ranges,
  64                         int param, struct sm_state *sm, char *implied_rl,
  65                         struct state_list *slist)
  66 {
  67         const char *param_name;
  68
  69         param_name = get_param_name(sm);
  70         if (!param_name)
  71                 return;
  72
  73         sql_insert_return_states(return_id, return_ranges, ADDED_VALUE, param,
  74                         param_name, implied_rl);
  75 }
  76
  77 static void print_return_value_param(int return_id, char *return_ranges, struct expression *expr, struct state_list *slist)
  78 {
  79         struct state_list *my_slist;
  80         struct sm_state *sm;
  81         struct smatch_state *extra;
  82         int param;
  83         struct range_list *rl;
  84
  85         my_slist = get_all_states_slist(my_id, slist);
  86
  87         FOR_EACH_PTR(my_slist, sm) {
  88                 if (!estate_rl(sm->state))
  89                         continue;
  90                 extra = get_state_slist(slist, SMATCH_EXTRA, sm->name, sm->sym);
  91                 if (!estate_rl(extra))
  92                         continue;
  93                 rl = rl_intersection(estate_rl(sm->state), estate_rl(extra));
  94                 if (!rl)
  95                         continue;
  96
  97                 param = get_param_num_from_sym(sm->sym);
  98                 if (param < 0)
  99                         continue;
 100                 if (!sm->sym->ident)
 101                         continue;
 102                 print_one_return_value_param(return_id, return_ranges, param, sm, show_rl(rl), slist);
 103         } END_FOR_EACH_PTR(sm);
 104 }
 105
 106 void register_param_set(int id)
 107 {
 108         my_id = id;
 109
 110         add_extra_mod_hook(&extra_mod_hook);
 111         add_unmatched_state_hook(my_id, &unmatched_state);
 112         add_merge_hook(my_id, &merge_estates);
 113         add_returned_state_callback(&print_return_value_param);
 114 }
 115