1/* Copyright (C) 1991-2016 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
23extern const struct _IO_jump_t _IO_strn_jumps libio_vtable attribute_hidden;
24
25/* Write formatted output into S, according to the format
26 string FORMAT, writing no more than MAXLEN characters. */
27/* VARARGS5 */
28int
29___vsnprintf_chk (char *s, size_t maxlen, int flags, size_t slen,
30 const char *format, va_list args)
31{
32 /* XXX Maybe for less strict version do not fail immediately.
33 Though, maxlen is supposed to be the size of buffer pointed
34 to by s, so a conforming program can't pass such maxlen
35 to *snprintf. */
36 if (__glibc_unlikely (slen < maxlen))
37 __chk_fail ();
38
39 _IO_strnfile sf;
40 int ret;
41#ifdef _IO_MTSAFE_IO
42 sf.f._sbf._f._lock = NULL;
43#endif
44
45 /* We need to handle the special case where MAXLEN is 0. Use the
46 overflow buffer right from the start. */
47 if (maxlen == 0)
48 {
49 s = sf.overflow_buf;
50 maxlen = sizeof (sf.overflow_buf);
51 }
52
53 _IO_no_init (&sf.f._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
54 _IO_JUMPS (&sf.f._sbf) = &_IO_strn_jumps;
55 s[0] = '\0';
56
57 /* For flags > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
58 can only come from read-only format strings. */
59 if (flags > 0)
60 sf.f._sbf._f._flags2 |= _IO_FLAGS2_FORTIFY;
61
62 _IO_str_init_static_internal (&sf.f, s, maxlen - 1, s);
63 ret = _IO_vfprintf (&sf.f._sbf._f, format, args);
64
65 if (sf.f._sbf._f._IO_buf_base != sf.overflow_buf)
66 *sf.f._sbf._f._IO_write_ptr = '\0';
67 return ret;
68}
69ldbl_hidden_def (___vsnprintf_chk, __vsnprintf_chk)
70ldbl_strong_alias (___vsnprintf_chk, __vsnprintf_chk)
71