aboutsummaryrefslogtreecommitdiffstats
path: root/src/lib/ffi/ffi_util.h
blob: 919efdd75c80d5ef7490f176d2d00193722e72e0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
/*
* (C) 2015,2017 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_FFI_UTILS_H__
#define BOTAN_FFI_UTILS_H__

#include <cstdint>
#include <memory>
#include <stdexcept>
#include <botan/exceptn.h>
#include <botan/mem_ops.h>

namespace Botan_FFI {

#define BOTAN_ASSERT_ARG_NON_NULL(p) \
   do { if(!p) throw Botan::Invalid_Argument("Argument " #p " is null"); } while(0)

class FFI_Error : public Botan::Exception
   {
   public:
      explicit FFI_Error(const std::string& what) : Exception("FFI error", what) {}
   };

template<typename T, uint32_t MAGIC>
struct botan_struct
   {
   public:
      botan_struct(T* obj) : m_magic(MAGIC), m_obj(obj) {}
      ~botan_struct() { m_magic = 0; m_obj.reset(); }

      bool magic_ok() const { return (m_magic == MAGIC); }

      T* get() const
         {
         if(magic_ok() == false)
            throw FFI_Error("Bad magic " + std::to_string(m_magic) +
                            " in ffi object expected " + std::to_string(MAGIC));
         return m_obj.get();
         }
   private:
      uint32_t m_magic = 0;
      std::unique_ptr<T> m_obj;
   };

#define BOTAN_FFI_DECLARE_STRUCT(NAME, TYPE, MAGIC) \
   struct NAME : public botan_struct<TYPE, MAGIC> { explicit NAME(TYPE* x) : botan_struct(x) {} }

// Declared in ffi.cpp
int ffi_error_exception_thrown(const char* func_name, const char* exn);

template<typename T, uint32_t M>
T& safe_get(botan_struct<T,M>* p)
   {
   if(!p)
      throw FFI_Error("Null pointer argument");
   if(T* t = p->get())
      return *t;
   throw FFI_Error("Invalid object pointer");
   }

template<typename T, uint32_t M>
const T& safe_get(const botan_struct<T,M>* p)
   {
   if(!p)
      throw FFI_Error("Null pointer argument");
   if(const T* t = p->get())
      return *t;
   throw FFI_Error("Invalid object pointer");
   }

template<typename Thunk>
int ffi_guard_thunk(const char* func_name, Thunk thunk)
   {
   try
      {
      return thunk();
      }
   catch(std::bad_alloc)
      {
      return ffi_error_exception_thrown(func_name, "bad_alloc");
      }
   catch(std::exception& e)
      {
      return ffi_error_exception_thrown(func_name, e.what());
      }
   catch(...)
      {
      return ffi_error_exception_thrown(func_name, "unknown exception");
      }

   return BOTAN_FFI_ERROR_UNKNOWN_ERROR;
   }

template<typename T, uint32_t M, typename F>
int apply_fn(botan_struct<T, M>* o, const char* func_name, F func)
   {
   try
      {
      if(!o)
         throw FFI_Error("Null object to " + std::string(func_name));
      if(T* t = o->get())
         return func(*t);
      }
   catch(std::bad_alloc)
      {
      return ffi_error_exception_thrown(func_name, "bad_alloc");
      }
   catch(std::exception& e)
      {
      return ffi_error_exception_thrown(func_name, e.what());
      }
   catch(...)
      {
      return ffi_error_exception_thrown(func_name, "unknown exception");
      }

   return BOTAN_FFI_ERROR_UNKNOWN_ERROR;
   }

#define BOTAN_FFI_DO(T, obj, param, block)                              \
   apply_fn(obj, BOTAN_CURRENT_FUNCTION,                                \
            [=](T& param) -> int { do { block } while(0); return BOTAN_FFI_SUCCESS; })

template<typename T, uint32_t M>
int ffi_delete_object(botan_struct<T, M>* obj, const char* func_name)
   {
   try
      {
      if(obj == nullptr)
         return BOTAN_FFI_SUCCESS; // ignore delete of null objects

      if(obj->magic_ok() == false)
         return BOTAN_FFI_ERROR_INVALID_INPUT;

      delete obj;
      return BOTAN_FFI_SUCCESS;
      }
   catch(std::exception& e)
      {
      return ffi_error_exception_thrown(func_name, e.what());
      }
   catch(...)
      {
      return ffi_error_exception_thrown(func_name, "unknown exception");
      }
   }

#define BOTAN_FFI_CHECKED_DELETE(o) ffi_delete_object(o, BOTAN_CURRENT_FUNCTION)

inline int write_output(uint8_t out[], size_t* out_len, const uint8_t buf[], size_t buf_len)
   {
   const size_t avail = *out_len;
   *out_len = buf_len;

   if(avail >= buf_len)
      {
      Botan::copy_mem(out, buf, buf_len);
      return BOTAN_FFI_SUCCESS;
      }
   else
      {
      Botan::clear_mem(out, avail);
      return BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE;
      }
   }

template<typename Alloc>
int write_vec_output(uint8_t out[], size_t* out_len, const std::vector<uint8_t, Alloc>& buf)
   {
   return write_output(out, out_len, buf.data(), buf.size());
   }

inline int write_str_output(uint8_t out[], size_t* out_len, const std::string& str)
   {
   return write_output(out, out_len,
                       reinterpret_cast<const uint8_t*>(str.c_str()),
                       str.size() + 1);
   }

inline int write_str_output(char out[], size_t* out_len, const std::string& str)
   {
   return write_str_output(reinterpret_cast<uint8_t*>(out), out_len, str);
   }

inline int write_str_output(char out[], size_t* out_len, const std::vector<uint8_t>& str_vec)
   {
   return write_output(reinterpret_cast<uint8_t*>(out), out_len,
                       reinterpret_cast<const uint8_t*>(str_vec.data()),
                       str_vec.size());
   }

}

#endif