debug/vsprintf_chk.c

   1 /* Copyright (C) 1994-2018 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <stdarg.h>
  19 #include <stdio.h>
  20 #include "../libio/libioP.h"
  21 #include "../libio/strfile.h"
  22
  23
  24 static int _IO_str_chk_overflow (FILE *fp, int c) __THROW;
  25
  26 static int
  27 _IO_str_chk_overflow (FILE *fp, int c)
  28 {
  29   /* When we come to here this means the user supplied buffer is
  30      filled.  */
  31   __chk_fail ();
  32 }
  33
  34
  35 static const struct _IO_jump_t _IO_str_chk_jumps libio_vtable =
  36 {
  37   JUMP_INIT_DUMMY,
  38   JUMP_INIT(finish, _IO_str_finish),
  39   JUMP_INIT(overflow, _IO_str_chk_overflow),
  40   JUMP_INIT(underflow, _IO_str_underflow),
  41   JUMP_INIT(uflow, _IO_default_uflow),
  42   JUMP_INIT(pbackfail, _IO_str_pbackfail),
  43   JUMP_INIT(xsputn, _IO_default_xsputn),
  44   JUMP_INIT(xsgetn, _IO_default_xsgetn),
  45   JUMP_INIT(seekoff, _IO_str_seekoff),
  46   JUMP_INIT(seekpos, _IO_default_seekpos),
  47   JUMP_INIT(setbuf, _IO_default_setbuf),
  48   JUMP_INIT(sync, _IO_default_sync),
  49   JUMP_INIT(doallocate, _IO_default_doallocate),
  50   JUMP_INIT(read, _IO_default_read),
  51   JUMP_INIT(write, _IO_default_write),
  52   JUMP_INIT(seek, _IO_default_seek),
  53   JUMP_INIT(close, _IO_default_close),
  54   JUMP_INIT(stat, _IO_default_stat),
  55   JUMP_INIT(showmanyc, _IO_default_showmanyc),
  56   JUMP_INIT(imbue, _IO_default_imbue)
  57 };
  58
  59
  60 int
  61 ___vsprintf_chk (char *s, int flags, size_t slen, const char *format,
  62                  va_list args)
  63 {
  64   _IO_strfile f;
  65   int ret;
  66 #ifdef _IO_MTSAFE_IO
  67   f._sbf._f._lock = NULL;
  68 #endif
  69
  70   if (slen == 0)
  71     __chk_fail ();
  72
  73   _IO_no_init (&f._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
  74   _IO_JUMPS (&f._sbf) = &_IO_str_chk_jumps;
  75   s[0] = '\0';
  76   _IO_str_init_static_internal (&f, s, slen - 1, s);
  77
  78   /* For flags > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
  79      can only come from read-only format strings.  */
  80   if (flags > 0)
  81     f._sbf._f._flags2 |= _IO_FLAGS2_FORTIFY;
  82
  83   ret = _IO_vfprintf (&f._sbf._f, format, args);
  84
  85   *f._sbf._f._IO_write_ptr = '\0';
  86   return ret;
  87 }
  88 ldbl_hidden_def (___vsprintf_chk, __vsprintf_chk)
  89 ldbl_strong_alias (___vsprintf_chk, __vsprintf_chk)