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         char *name;
  24
  25         expr = strip_expr(expr);
  26         if (expr->type == EXPR_SYMBOL) {
  27                 int param;
  28                 char buf[256];
  29
  30                 param = get_param_num_from_sym(expr->symbol);
  31                 if (param >= 0) {
  32                         snprintf(buf, sizeof(buf), "%s param %d", get_function(), param);
  33                         return alloc_string(buf);
  34                 }
  35
  36                 return expr_to_var(expr);
  37         }
  38         name = get_member_name(expr);
  39         if (name)
  40                 return name;
  41         return expr_to_var(expr);
  42 }
  43
  44 static void match_passes_function_pointer(struct expression *expr)
  45 {
  46         struct expression *arg, *tmp;
  47         struct symbol *type;
  48         char *called_name;
  49         char *fn_name;
  50         char ptr_name[256];
  51         int i;
  52
  53
  54         i = -1;
  55         FOR_EACH_PTR(expr->args, arg) {
  56                 i++;
  57
  58                 tmp = strip_expr(arg);
  59                 if (tmp->type == EXPR_PREOP && tmp->op == '&')
  60                         tmp = strip_expr(tmp->unop);
  61
  62                 type = get_type(tmp);
  63                 if (type && type->type == SYM_PTR)
  64                         type = get_real_base_type(type);
  65                 if (!type || type->type != SYM_FN)
  66                         continue;
  67
  68                 called_name = expr_to_var(expr->fn);
  69                 if (!called_name)
  70                         return;
  71                 fn_name = get_fnptr_name(tmp);
  72                 if (!fn_name)
  73                         goto free;
  74
  75                 snprintf(ptr_name, sizeof(ptr_name), "%s param %d", called_name, i);
  76                 sql_insert_function_ptr(fn_name, ptr_name);
  77 free:
  78                 free_string(fn_name);
  79                 free_string(called_name);
  80         } END_FOR_EACH_PTR(arg);
  81
  82 }
  83
  84 static void match_function_assign(struct expression *expr)
  85 {
  86         struct expression *right;
  87         struct symbol *sym;
  88         char *fn_name;
  89         char *ptr_name;
  90
  91         right = strip_expr(expr->right);
  92         if (right->type == EXPR_PREOP && right->op == '&')
  93                 right = strip_expr(right->unop);
  94         if (right->type != EXPR_SYMBOL)
  95                 return;
  96         sym = get_type(right);
  97         if (!sym || sym->type != SYM_FN)
  98                 return;
  99
 100         fn_name = expr_to_var(right);
 101         ptr_name = get_fnptr_name(expr->left);
 102         if (!fn_name || !ptr_name)
 103                 goto free;
 104
 105         sql_insert_function_ptr(fn_name, ptr_name);
 106
 107 free:
 108         free_string(fn_name);
 109         free_string(ptr_name);
 110 }
 111
 112 void register_function_ptrs(int id)
 113 {
 114         my_id = id;
 115
 116         if (!option_info)
 117                 return;
 118
 119         add_hook(&match_passes_function_pointer, FUNCTION_CALL_HOOK);
 120         add_hook(&match_function_assign, ASSIGNMENT_HOOK);
 121         add_hook(&match_function_assign, GLOBAL_ASSIGNMENT_HOOK);
 122 }