1/* Copyright (C) 1995-2018 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 As a special exception, if you link the code in this file with
19 files compiled with a GNU compiler to produce an executable,
20 that does not cause the resulting executable to be covered by
21 the GNU Lesser General Public License. This exception does not
22 however invalidate any other reasons why the executable file
23 might be covered by the GNU Lesser General Public License.
24 This exception applies to code released by its copyright holders
25 in files containing the exception. */
26
27#include <malloc.h>
28#include <string.h>
29#include <stdio.h>
30#include <stdio_ext.h>
31#include "../libio/libioP.h"
32#include "../libio/strfile.h"
33
34int
35__vasprintf_chk (char **result_ptr, int flags, const char *format,
36 va_list args)
37{
38 /* Initial size of the buffer to be used. Will be doubled each time an
39 overflow occurs. */
40 const _IO_size_t init_string_size = 100;
41 char *string;
42 _IO_strfile sf;
43 int ret;
44 _IO_size_t needed;
45 _IO_size_t allocated;
46 /* No need to clear the memory here (unlike for open_memstream) since
47 we know we will never seek on the stream. */
48 string = (char *) malloc (init_string_size);
49 if (string == NULL)
50 return -1;
51#ifdef _IO_MTSAFE_IO
52 sf._sbf._f._lock = NULL;
53#endif
54 _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
55 _IO_JUMPS (&sf._sbf) = &_IO_str_jumps;
56 _IO_str_init_static_internal (&sf, string, init_string_size, string);
57 sf._sbf._f._flags &= ~_IO_USER_BUF;
58 sf._s._allocate_buffer = (_IO_alloc_type) malloc;
59 sf._s._free_buffer = (_IO_free_type) free;
60
61 /* For flags > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
62 can only come from read-only format strings. */
63 if (flags > 0)
64 sf._sbf._f._flags2 |= _IO_FLAGS2_FORTIFY;
65
66 ret = _IO_vfprintf (&sf._sbf._f, format, args);
67 if (ret < 0)
68 {
69 free (sf._sbf._f._IO_buf_base);
70 return ret;
71 }
72 /* Only use realloc if the size we need is of the same (binary)
73 order of magnitude then the memory we allocated. */
74 needed = sf._sbf._f._IO_write_ptr - sf._sbf._f._IO_write_base + 1;
75 allocated = sf._sbf._f._IO_write_end - sf._sbf._f._IO_write_base;
76 if ((allocated >> 1) <= needed)
77 *result_ptr = (char *) realloc (sf._sbf._f._IO_buf_base, needed);
78 else
79 {
80 *result_ptr = (char *) malloc (needed);
81 if (*result_ptr != NULL)
82 {
83 memcpy (*result_ptr, sf._sbf._f._IO_buf_base, needed - 1);
84 free (sf._sbf._f._IO_buf_base);
85 }
86 else
87 /* We have no choice, use the buffer we already have. */
88 *result_ptr = (char *) realloc (sf._sbf._f._IO_buf_base, needed);
89 }
90 if (*result_ptr == NULL)
91 *result_ptr = sf._sbf._f._IO_buf_base;
92 (*result_ptr)[needed - 1] = '\0';
93 return ret;
94}
95libc_hidden_def (__vasprintf_chk)
96