1/* Copyright (C) 1996-2023 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 <assert.h>
19#include <dlfcn.h>
20#include <errno.h>
21#include <gconv.h>
22#include <string.h>
23#include <wchar.h>
24#include <wcsmbsload.h>
25
26#include <pointer_guard.h>
27
28#ifndef EILSEQ
29# define EILSEQ EINVAL
30#endif
31
32
33/* This is the private state used if PS is NULL. */
34static mbstate_t state;
35
36/* This is a non-standard function but it is very useful in the
37 implementation of stdio because we have to deal with unterminated
38 buffers. At most NMC bytes will be converted. */
39size_t
40__mbsnrtowcs (wchar_t *dst, const char **src, size_t nmc, size_t len,
41 mbstate_t *ps)
42{
43 const unsigned char *srcend;
44 struct __gconv_step_data data;
45 size_t result;
46 int status;
47 struct __gconv_step *towc;
48 size_t dummy;
49 const struct gconv_fcts *fcts;
50
51 /* Tell where we want the result. */
52 data.__invocation_counter = 0;
53 data.__internal_use = 1;
54 data.__flags = __GCONV_IS_LAST;
55 data.__statep = ps ?: &state;
56
57 if (nmc == 0)
58 return 0;
59 srcend = (const unsigned char *) *src + __strnlen (*src, nmc - 1) + 1;
60
61 /* Get the conversion functions. */
62 fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
63
64 /* Get the structure with the function pointers. */
65 towc = fcts->towc;
66 __gconv_fct fct = towc->__fct;
67 if (towc->__shlib_handle != NULL)
68 PTR_DEMANGLE (fct);
69
70 /* We have to handle DST == NULL special. */
71 if (dst == NULL)
72 {
73 mbstate_t temp_state;
74 wchar_t buf[64]; /* Just an arbitrary size. */
75 const unsigned char *inbuf = (const unsigned char *) *src;
76
77 temp_state = *data.__statep;
78 data.__statep = &temp_state;
79
80 result = 0;
81 data.__outbufend = (unsigned char *) buf + sizeof (buf);
82 do
83 {
84 data.__outbuf = (unsigned char *) buf;
85
86 status = DL_CALL_FCT (fct, (towc, &data, &inbuf, srcend, NULL,
87 &dummy, 0, 1));
88
89 result += (wchar_t *) data.__outbuf - buf;
90 }
91 while (status == __GCONV_FULL_OUTPUT);
92
93 if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
94 && ((wchar_t *) data.__outbuf)[-1] == L'\0')
95 /* Don't count the NUL character in. */
96 --result;
97 }
98 else
99 {
100 /* This code is based on the safe assumption that all internal
101 multi-byte encodings use the NUL byte only to mark the end
102 of the string. */
103 data.__outbuf = (unsigned char *) dst;
104 data.__outbufend = data.__outbuf + len * sizeof (wchar_t);
105
106 status = DL_CALL_FCT (fct,
107 (towc, &data, (const unsigned char **) src, srcend,
108 NULL, &dummy, 0, 1));
109
110 result = (wchar_t *) data.__outbuf - dst;
111
112 /* We have to determine whether the last character converted
113 is the NUL character. */
114 if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
115 && (assert (result > 0),
116 ((wchar_t *) dst)[result - 1] == L'\0'))
117 {
118 assert (__mbsinit (data.__statep));
119 *src = NULL;
120 --result;
121 }
122 }
123
124 /* There must not be any problems with the conversion but illegal input
125 characters. */
126 assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
127 || status == __GCONV_ILLEGAL_INPUT
128 || status == __GCONV_INCOMPLETE_INPUT
129 || status == __GCONV_FULL_OUTPUT);
130
131 if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
132 && status != __GCONV_EMPTY_INPUT && status != __GCONV_INCOMPLETE_INPUT)
133 {
134 result = (size_t) -1;
135 __set_errno (EILSEQ);
136 }
137
138 return result;
139}
140weak_alias (__mbsnrtowcs, mbsnrtowcs)
141