lib/util/string_wrappers.h

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    string wrappers, for checking string sizes
   5
   6    Copyright (C) Andrew Tridgell 1994-2011
   7    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #ifndef _STRING_WRAPPERS_H
  24 #define _STRING_WRAPPERS_H
  25
  26 #define strlcpy_base(dest, src, base, size) \
  27 do { \
  28         const char *_strlcpy_base_src = (const char *)src; \
  29         strlcpy((dest), _strlcpy_base_src? _strlcpy_base_src : "", (size)-PTR_DIFF((dest),(base))); \
  30 } while (0)
  31
  32 /* String copy functions - macro hell below adds 'type checking' (limited,
  33    but the best we can do in C) */
  34
  35 #define fstrcpy(d,s) \
  36 do { \
  37         const char *_fstrcpy_src = (const char *)(s); \
  38         strlcpy((d),_fstrcpy_src ? _fstrcpy_src : "",sizeof(fstring)); \
  39 } while (0)
  40
  41 #define fstrcat(d,s) \
  42 do { \
  43         const char *_fstrcat_src = (const char *)(s); \
  44         strlcat((d),_fstrcat_src ? _fstrcat_src : "",sizeof(fstring)); \
  45 } while (0)
  46 #define nstrcpy(d,s) \
  47 do { \
  48         const char *_nstrcpy_src = (const char *)(s); \
  49         strlcpy((d),_nstrcpy_src ? _nstrcpy_src : "",sizeof(fstring)); \
  50 } while (0)
  51 #define unstrcpy(d,s) \
  52 do { \
  53         const char *_unstrcpy_src = (const char *)(s); \
  54         strlcpy((d),_unstrcpy_src ? _unstrcpy_src : "",sizeof(fstring)); \
  55 } while (0)
  56
  57 #ifdef HAVE_COMPILER_WILL_OPTIMIZE_OUT_FNS
  58
  59 /* We need a number of different prototypes for our
  60    non-existant fuctions */
  61 char * __unsafe_string_function_usage_here__(void);
  62
  63 size_t __unsafe_string_function_usage_here_size_t__(void);
  64
  65 #define CHECK_STRING_SIZE(d, len) (sizeof(d) != (len) && sizeof(d) != sizeof(char *))
  66
  67 /* if the compiler will optimize out function calls, then use this to tell if we are
  68    have the correct types (this works only where sizeof() returns the size of the buffer, not
  69    the size of the pointer). */
  70
  71 #define push_string_check(dest, src, dest_len, flags) \
  72     (CHECK_STRING_SIZE(dest, dest_len) \
  73     ? __unsafe_string_function_usage_here_size_t__() \
  74     : push_string_check_fn(dest, src, dest_len, flags))
  75
  76 #define srvstr_push(base_ptr, smb_flags2, dest, src, dest_len, flags) \
  77     (CHECK_STRING_SIZE(dest, dest_len) \
  78     ? __unsafe_string_function_usage_here_size_t__() \
  79     : srvstr_push_fn(base_ptr, smb_flags2, dest, src, dest_len, flags))
  80
  81 /* This allows the developer to choose to check the arguments to
  82    strlcpy.  if the compiler will optimize out function calls, then
  83    use this to tell if we are have the correct size buffer (this works only
  84    where sizeof() returns the size of the buffer, not the size of the
  85    pointer), so stack and static variables only */
  86
  87 #define checked_strlcpy(dest, src, size) \
  88     (sizeof(dest) != (size) \
  89     ? __unsafe_string_function_usage_here_size_t__() \
  90      : strlcpy(dest, src, size))
  91
  92 #else
  93
  94 #define push_string_check push_string_check_fn
  95 #define srvstr_push srvstr_push_fn
  96 #define checked_strlcpy strlcpy
  97
  98 #endif
  99
 100 #endif