vfs: check userland buffers before reading them.
[haiku.git] / src / system / libroot / posix / glibc / libio / vswprintf.c
blob3ec44d1463025a8740e8ef6fd09408213d7b13b7
1 /* Copyright (C) 1994,1997,1999,2000,2001,2002 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA.
19 As a special exception, if you link the code in this file with
20 files compiled with a GNU compiler to produce an executable,
21 that does not cause the resulting executable to be covered by
22 the GNU Lesser General Public License. This exception does not
23 however invalidate any other reasons why the executable file
24 might be covered by the GNU Lesser General Public License.
25 This exception applies to code released by its copyright holders
26 in files containing the exception. */
28 #include "libioP.h"
29 #include "strfile.h"
32 typedef struct
34 _IO_strfile f;
35 /* This is used for the characters which do not fit in the buffer
36 provided by the user. */
37 wchar_t overflow_buf[64];
38 } _IO_strnfile;
41 static wint_t _IO_wstrn_overflow __P ((_IO_FILE *fp, wint_t c));
43 static wint_t
44 _IO_wstrn_overflow (fp, c)
45 _IO_FILE *fp;
46 wint_t c;
48 /* When we come to here this means the user supplied buffer is
49 filled. But since we must return the number of characters which
50 would have been written in total we must provide a buffer for
51 further use. We can do this by writing on and on in the overflow
52 buffer in the _IO_strnfile structure. */
53 _IO_strnfile *snf = (_IO_strnfile *) fp;
55 if (fp->_wide_data->_IO_buf_base != snf->overflow_buf)
57 INTUSE(_IO_wsetb) (fp, snf->overflow_buf,
58 snf->overflow_buf + (sizeof (snf->overflow_buf)
59 / sizeof (wchar_t)), 0);
61 fp->_wide_data->_IO_write_base = snf->overflow_buf;
62 fp->_wide_data->_IO_read_base = snf->overflow_buf;
63 fp->_wide_data->_IO_read_ptr = snf->overflow_buf;
64 fp->_wide_data->_IO_read_end = (snf->overflow_buf
65 + (sizeof (snf->overflow_buf)
66 / sizeof (wchar_t)));
69 fp->_wide_data->_IO_write_ptr = snf->overflow_buf;
70 fp->_wide_data->_IO_write_end = snf->overflow_buf;
72 /* Since we are not really interested in storing the characters
73 which do not fit in the buffer we simply ignore it. */
74 return c;
78 static struct _IO_jump_t _IO_wstrn_jumps =
80 JUMP_INIT_DUMMY,
81 JUMP_INIT(finish, _IO_wstr_finish),
82 JUMP_INIT(overflow, (_IO_overflow_t) _IO_wstrn_overflow),
83 JUMP_INIT(underflow, (_IO_underflow_t) _IO_wstr_underflow),
84 JUMP_INIT(uflow, (_IO_underflow_t) INTUSE(_IO_wdefault_uflow)),
85 JUMP_INIT(pbackfail, (_IO_pbackfail_t) _IO_wstr_pbackfail),
86 JUMP_INIT(xsputn, INTUSE(_IO_wdefault_xsputn)),
87 JUMP_INIT(xsgetn, INTUSE(_IO_wdefault_xsgetn)),
88 JUMP_INIT(seekoff, _IO_wstr_seekoff),
89 JUMP_INIT(seekpos, _IO_default_seekpos),
90 JUMP_INIT(setbuf, _IO_default_setbuf),
91 JUMP_INIT(sync, _IO_default_sync),
92 JUMP_INIT(doallocate, INTUSE(_IO_wdefault_doallocate)),
93 JUMP_INIT(read, _IO_default_read),
94 JUMP_INIT(write, _IO_default_write),
95 JUMP_INIT(seek, _IO_default_seek),
96 JUMP_INIT(close, _IO_default_close),
97 JUMP_INIT(stat, _IO_default_stat),
98 JUMP_INIT(showmanyc, _IO_default_showmanyc),
99 JUMP_INIT(imbue, _IO_default_imbue)
104 _IO_vswprintf (string, maxlen, format, args)
105 wchar_t *string;
106 _IO_size_t maxlen;
107 const wchar_t *format;
108 _IO_va_list args;
110 _IO_strnfile sf;
111 int ret;
112 struct _IO_wide_data wd;
113 #ifdef _IO_MTSAFE_IO
114 sf.f._sbf._f._lock = NULL;
115 #endif
117 if (maxlen == 0)
118 /* Since we have to write at least the terminating L'\0' a buffer
119 length of zero always makes the function fail. */
120 return -1;
122 _IO_no_init (&sf.f._sbf._f, _IO_USER_LOCK, 0, &wd, &_IO_wstrn_jumps);
123 _IO_fwide (&sf.f._sbf._f, 1);
124 string[0] = L'\0';
125 _IO_wstr_init_static (&sf.f._sbf._f, string, maxlen - 1, string);
126 ret = _IO_vfwprintf ((_IO_FILE *) &sf.f._sbf, format, args);
128 if (sf.f._sbf._f._wide_data->_IO_buf_base == sf.overflow_buf)
129 /* ISO C99 requires swprintf/vswprintf to return an error if the
130 output does not fit int he provided buffer. */
131 return -1;
133 /* Terminate the string. */
134 *sf.f._sbf._f._wide_data->_IO_write_ptr = '\0';
136 return ret;
139 #ifdef weak_alias
140 weak_alias (_IO_vswprintf, __vswprintf)
141 weak_alias (_IO_vswprintf, vswprintf)
142 #endif