1/* Copyright (C) 1995-2021 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 <https://www.gnu.org/licenses/>. */
17
18#include "libioP.h"
19#include "strfile.h"
20#include <stdio.h>
21#include <stdlib.h>
22
23
24struct _IO_FILE_memstream
25{
26 _IO_strfile _sf;
27 char **bufloc;
28 size_t *sizeloc;
29};
30
31
32static int _IO_mem_sync (FILE* fp) __THROW;
33static void _IO_mem_finish (FILE* fp, int) __THROW;
34
35
36static const struct _IO_jump_t _IO_mem_jumps libio_vtable =
37{
38 JUMP_INIT_DUMMY,
39 JUMP_INIT (finish, _IO_mem_finish),
40 JUMP_INIT (overflow, _IO_str_overflow),
41 JUMP_INIT (underflow, _IO_str_underflow),
42 JUMP_INIT (uflow, _IO_default_uflow),
43 JUMP_INIT (pbackfail, _IO_str_pbackfail),
44 JUMP_INIT (xsputn, _IO_default_xsputn),
45 JUMP_INIT (xsgetn, _IO_default_xsgetn),
46 JUMP_INIT (seekoff, _IO_str_seekoff),
47 JUMP_INIT (seekpos, _IO_default_seekpos),
48 JUMP_INIT (setbuf, _IO_default_setbuf),
49 JUMP_INIT (sync, _IO_mem_sync),
50 JUMP_INIT (doallocate, _IO_default_doallocate),
51 JUMP_INIT (read, _IO_default_read),
52 JUMP_INIT (write, _IO_default_write),
53 JUMP_INIT (seek, _IO_default_seek),
54 JUMP_INIT (close, _IO_default_close),
55 JUMP_INIT (stat, _IO_default_stat),
56 JUMP_INIT(showmanyc, _IO_default_showmanyc),
57 JUMP_INIT(imbue, _IO_default_imbue)
58};
59
60/* Open a stream that writes into a malloc'd buffer that is expanded as
61 necessary. *BUFLOC and *SIZELOC are updated with the buffer's location
62 and the number of characters written on fflush or fclose. */
63FILE *
64__open_memstream (char **bufloc, size_t *sizeloc)
65{
66 struct locked_FILE
67 {
68 struct _IO_FILE_memstream fp;
69#ifdef _IO_MTSAFE_IO
70 _IO_lock_t lock;
71#endif
72 struct _IO_wide_data wd;
73 } *new_f;
74 char *buf;
75
76 new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
77 if (new_f == NULL)
78 return NULL;
79#ifdef _IO_MTSAFE_IO
80 new_f->fp._sf._sbf._f._lock = &new_f->lock;
81#endif
82
83 buf = calloc (1, BUFSIZ);
84 if (buf == NULL)
85 {
86 free (new_f);
87 return NULL;
88 }
89 _IO_init_internal (&new_f->fp._sf._sbf._f, 0);
90 _IO_JUMPS_FILE_plus (&new_f->fp._sf._sbf) = &_IO_mem_jumps;
91 _IO_str_init_static_internal (&new_f->fp._sf, buf, BUFSIZ, buf);
92 new_f->fp._sf._sbf._f._flags &= ~_IO_USER_BUF;
93 new_f->fp._sf._s._allocate_buffer_unused = (_IO_alloc_type) malloc;
94 new_f->fp._sf._s._free_buffer_unused = (_IO_free_type) free;
95
96 new_f->fp.bufloc = bufloc;
97 new_f->fp.sizeloc = sizeloc;
98
99 /* Disable single thread optimization. BZ 21735. */
100 new_f->fp._sf._sbf._f._flags2 |= _IO_FLAGS2_NEED_LOCK;
101
102 return (FILE *) &new_f->fp._sf._sbf;
103}
104libc_hidden_def (__open_memstream)
105weak_alias (__open_memstream, open_memstream)
106
107
108static int
109_IO_mem_sync (FILE *fp)
110{
111 struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
112
113 if (fp->_IO_write_ptr == fp->_IO_write_end)
114 {
115 _IO_str_overflow (fp, '\0');
116 --fp->_IO_write_ptr;
117 }
118
119 *mp->bufloc = fp->_IO_write_base;
120 *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
121
122 return 0;
123}
124
125
126static void
127_IO_mem_finish (FILE *fp, int dummy)
128{
129 struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
130
131 *mp->bufloc = (char *) realloc (fp->_IO_write_base,
132 fp->_IO_write_ptr - fp->_IO_write_base + 1);
133 if (*mp->bufloc != NULL)
134 {
135 (*mp->bufloc)[fp->_IO_write_ptr - fp->_IO_write_base] = '\0';
136 *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
137
138 fp->_IO_buf_base = NULL;
139 }
140
141 _IO_str_finish (fp, 0);
142}
143