smatch_function_ptrs.c

   1 /*
   2  * smatch/smatch_function_ptrs.c
   3  *
   4  * Copyright (C) 2013 Oracle.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * Track how functions are saved as various struct members or passed as
  12  * parameters.
  13  *
  14  */
  15
  16 #include "smatch.h"
  17 #include "smatch_slist.h"
  18
  19 static int my_id;
  20
  21 char *get_fnptr_name(struct expression *expr)
  22 {
  23         if (expr->type == EXPR_SYMBOL) {
  24                 int param;
  25                 char buf[256];
  26
  27                 param = get_param_num_from_sym(expr->symbol);
  28                 if (param >= 0) {
  29                         snprintf(buf, sizeof(buf), "%s param %d", get_function(), param);
  30                         return alloc_string(buf);
  31                 }
  32
  33                 return expr_to_var(expr);
  34         }
  35         return get_member_name(expr);
  36 }
  37
  38 static void match_passes_function_pointer(struct expression *expr)
  39 {
  40         struct expression *arg, *tmp;
  41         struct symbol *type;
  42         char *called_name;
  43         char *fn_name;
  44         char ptr_name[256];
  45         int i;
  46
  47
  48         i = -1;
  49         FOR_EACH_PTR(expr->args, arg) {
  50                 i++;
  51
  52                 tmp = strip_expr(arg);
  53                 if (tmp->type == EXPR_PREOP && tmp->op == '&')
  54                         tmp = strip_expr(tmp->unop);
  55                 type = get_type(tmp);
  56                 if (!type || type->type != SYM_FN)
  57                         continue;
  58
  59                 called_name = expr_to_var(expr->fn);
  60                 if (!called_name)
  61                         return;
  62                 fn_name = expr_to_var(tmp);
  63                 if (!fn_name)
  64                         goto free;
  65
  66                 snprintf(ptr_name, sizeof(ptr_name), "%s param %d", called_name, i);
  67                 sql_insert_function_ptr(fn_name, ptr_name);
  68 free:
  69                 free_string(fn_name);
  70                 free_string(called_name);
  71         } END_FOR_EACH_PTR(arg);
  72
  73 }
  74
  75 static void match_function_assign(struct expression *expr)
  76 {
  77         struct expression *right = expr->right;
  78         struct symbol *sym;
  79         char *fn_name;
  80         char *ptr_name;
  81
  82         if (right->type == EXPR_PREOP && right->op == '&')
  83                 right = strip_expr(right->unop);
  84         if (right->type != EXPR_SYMBOL)
  85                 return;
  86         sym = get_type(right);
  87         if (!sym || sym->type != SYM_FN)
  88                 return;
  89
  90         fn_name = expr_to_var(right);
  91         ptr_name = get_fnptr_name(expr->left);
  92         if (!fn_name || !ptr_name)
  93                 goto free;
  94
  95         sql_insert_function_ptr(fn_name, ptr_name);
  96
  97 free:
  98         free_string(fn_name);
  99         free_string(ptr_name);
 100 }
 101
 102 void register_function_ptrs(int id)
 103 {
 104         my_id = id;
 105
 106         if (!option_info)
 107                 return;
 108
 109         add_hook(&match_passes_function_pointer, FUNCTION_CALL_HOOK);
 110         add_hook(&match_function_assign, ASSIGNMENT_HOOK);
 111 }