libio/wstrops.c

   1 /* Copyright (C) 1993-2024 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    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 <assert.h>
  28 #include "strfile.h"
  29 #include "libioP.h"
  30 #include <string.h>
  31 #include <wchar.h>
  32 #include <stdio_ext.h>
  33
  34 void
  35 _IO_wstr_init_static (FILE *fp, wchar_t *ptr, size_t size,
  36                       wchar_t *pstart)
  37 {
  38   wchar_t *end;
  39
  40   if (size == 0)
  41     end = ptr + __wcslen (ptr);
  42   else if ((size_t) ptr + size * sizeof (wchar_t) > (size_t) ptr)
  43     end = ptr + size;
  44   else
  45     /* Even for misaligned ptr make sure there is integral number of wide
  46        characters.  */
  47     end = ptr + (-1 - (size_t) ptr) / sizeof (wchar_t);
  48   _IO_wsetb (fp, ptr, end, 0);
  49
  50   fp->_wide_data->_IO_write_base = ptr;
  51   fp->_wide_data->_IO_read_base = ptr;
  52   fp->_wide_data->_IO_read_ptr = ptr;
  53   if (pstart)
  54     {
  55       fp->_wide_data->_IO_write_ptr = pstart;
  56       fp->_wide_data->_IO_write_end = end;
  57       fp->_wide_data->_IO_read_end = pstart;
  58     }
  59   else
  60     {
  61       fp->_wide_data->_IO_write_ptr = ptr;
  62       fp->_wide_data->_IO_write_end = ptr;
  63       fp->_wide_data->_IO_read_end = end;
  64     }
  65   /* A null _allocate_buffer function flags the strfile as being static. */
  66   (((_IO_strfile *) fp)->_s._allocate_buffer_unused) = (_IO_alloc_type)0;
  67 }
  68
  69 wint_t
  70 _IO_wstr_overflow (FILE *fp, wint_t c)
  71 {
  72   int flush_only = c == WEOF;
  73   size_t pos;
  74   if (fp->_flags & _IO_NO_WRITES)
  75       return flush_only ? 0 : WEOF;
  76   if ((fp->_flags & _IO_TIED_PUT_GET) && !(fp->_flags & _IO_CURRENTLY_PUTTING))
  77     {
  78       fp->_flags |= _IO_CURRENTLY_PUTTING;
  79       fp->_wide_data->_IO_write_ptr = fp->_wide_data->_IO_read_ptr;
  80       fp->_wide_data->_IO_read_ptr = fp->_wide_data->_IO_read_end;
  81     }
  82   pos = fp->_wide_data->_IO_write_ptr - fp->_wide_data->_IO_write_base;
  83   if (pos >= (size_t) (_IO_wblen (fp) + flush_only))
  84     {
  85       if (fp->_flags2 & _IO_FLAGS2_USER_WBUF) /* not allowed to enlarge */
  86         return WEOF;
  87       else
  88         {
  89           wchar_t *new_buf;
  90           wchar_t *old_buf = fp->_wide_data->_IO_buf_base;
  91           size_t old_wblen = _IO_wblen (fp);
  92           size_t new_size = 2 * old_wblen + 100;
  93
  94           if (__glibc_unlikely (new_size < old_wblen)
  95               || __glibc_unlikely (new_size > SIZE_MAX / sizeof (wchar_t)))
  96             return EOF;
  97
  98           new_buf = malloc (new_size * sizeof (wchar_t));
  99           if (new_buf == NULL)
 100             {
 101               /*          __ferror(fp) = 1; */
 102               return WEOF;
 103             }
 104           if (old_buf)
 105             {
 106               __wmemcpy (new_buf, old_buf, old_wblen);
 107               free (old_buf);
 108               /* Make sure _IO_setb won't try to delete _IO_buf_base. */
 109               fp->_wide_data->_IO_buf_base = NULL;
 110             }
 111
 112           __wmemset (new_buf + old_wblen, L'\0', new_size - old_wblen);
 113
 114           _IO_wsetb (fp, new_buf, new_buf + new_size, 1);
 115           fp->_wide_data->_IO_read_base =
 116             new_buf + (fp->_wide_data->_IO_read_base - old_buf);
 117           fp->_wide_data->_IO_read_ptr =
 118             new_buf + (fp->_wide_data->_IO_read_ptr - old_buf);
 119           fp->_wide_data->_IO_read_end =
 120             new_buf + (fp->_wide_data->_IO_read_end - old_buf);
 121           fp->_wide_data->_IO_write_ptr =
 122             new_buf + (fp->_wide_data->_IO_write_ptr - old_buf);
 123
 124           fp->_wide_data->_IO_write_base = new_buf;
 125           fp->_wide_data->_IO_write_end = fp->_wide_data->_IO_buf_end;
 126         }
 127     }
 128
 129   if (!flush_only)
 130     *fp->_wide_data->_IO_write_ptr++ = c;
 131   if (fp->_wide_data->_IO_write_ptr > fp->_wide_data->_IO_read_end)
 132     fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_write_ptr;
 133   if (flush_only)
 134     return 0;
 135   else
 136     return c;
 137 }
 138
 139
 140 wint_t
 141 _IO_wstr_underflow (FILE *fp)
 142 {
 143   if (fp->_wide_data->_IO_write_ptr > fp->_wide_data->_IO_read_end)
 144     fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_write_ptr;
 145   if ((fp->_flags & _IO_TIED_PUT_GET) && (fp->_flags & _IO_CURRENTLY_PUTTING))
 146     {
 147       fp->_flags &= ~_IO_CURRENTLY_PUTTING;
 148       fp->_wide_data->_IO_read_ptr = fp->_wide_data->_IO_write_ptr;
 149       fp->_wide_data->_IO_write_ptr = fp->_wide_data->_IO_write_end;
 150     }
 151   if (fp->_wide_data->_IO_read_ptr < fp->_wide_data->_IO_read_end)
 152     return *fp->_wide_data->_IO_read_ptr;
 153   else
 154     return WEOF;
 155 }
 156
 157
 158 /* The size of the valid part of the buffer.  */
 159 ssize_t
 160 _IO_wstr_count (FILE *fp)
 161 {
 162   struct _IO_wide_data *wd = fp->_wide_data;
 163
 164   return ((wd->_IO_write_ptr > wd->_IO_read_end
 165            ? wd->_IO_write_ptr : wd->_IO_read_end)
 166           - wd->_IO_read_base);
 167 }
 168
 169
 170 static int
 171 enlarge_userbuf (FILE *fp, off64_t offset, int reading)
 172 {
 173   if ((ssize_t) offset <= _IO_wblen (fp))
 174     return 0;
 175
 176   struct _IO_wide_data *wd = fp->_wide_data;
 177
 178   ssize_t oldend = wd->_IO_write_end - wd->_IO_write_base;
 179
 180   /* Try to enlarge the buffer.  */
 181   if (fp->_flags2 & _IO_FLAGS2_USER_WBUF)
 182     /* User-provided buffer.  */
 183     return 1;
 184
 185   size_t newsize = offset + 100;
 186   if (__glibc_unlikely (newsize > SIZE_MAX / sizeof (wchar_t)))
 187     return 1;
 188
 189   wchar_t *oldbuf = wd->_IO_buf_base;
 190   wchar_t *newbuf = malloc (newsize * sizeof (wchar_t));
 191   if (newbuf == NULL)
 192     return 1;
 193
 194   if (oldbuf != NULL)
 195     {
 196       __wmemcpy (newbuf, oldbuf, _IO_wblen (fp));
 197       free (oldbuf);
 198       /* Make sure _IO_setb won't try to delete
 199          _IO_buf_base. */
 200       wd->_IO_buf_base = NULL;
 201     }
 202
 203   _IO_wsetb (fp, newbuf, newbuf + newsize, 1);
 204
 205   if (reading)
 206     {
 207       wd->_IO_write_base = newbuf + (wd->_IO_write_base - oldbuf);
 208       wd->_IO_write_ptr = newbuf + (wd->_IO_write_ptr - oldbuf);
 209       wd->_IO_write_end = newbuf + (wd->_IO_write_end - oldbuf);
 210       wd->_IO_read_ptr = newbuf + (wd->_IO_read_ptr - oldbuf);
 211
 212       wd->_IO_read_base = newbuf;
 213       wd->_IO_read_end = wd->_IO_buf_end;
 214     }
 215   else
 216     {
 217       wd->_IO_read_base = newbuf + (wd->_IO_read_base - oldbuf);
 218       wd->_IO_read_ptr = newbuf + (wd->_IO_read_ptr - oldbuf);
 219       wd->_IO_read_end = newbuf + (wd->_IO_read_end - oldbuf);
 220       wd->_IO_write_ptr = newbuf + (wd->_IO_write_ptr - oldbuf);
 221
 222       wd->_IO_write_base = newbuf;
 223       wd->_IO_write_end = wd->_IO_buf_end;
 224     }
 225
 226   /* Clear the area between the last write position and th
 227      new position.  */
 228   assert (offset >= oldend);
 229   if (reading)
 230     __wmemset (wd->_IO_read_base + oldend, L'\0', offset - oldend);
 231   else
 232     __wmemset (wd->_IO_write_base + oldend, L'\0', offset - oldend);
 233
 234   return 0;
 235 }
 236
 237 static void
 238 _IO_wstr_switch_to_get_mode (FILE *fp)
 239 {
 240   if (_IO_in_backup (fp))
 241     fp->_wide_data->_IO_read_base = fp->_wide_data->_IO_backup_base;
 242   else
 243     {
 244       fp->_wide_data->_IO_read_base = fp->_wide_data->_IO_buf_base;
 245       if (fp->_wide_data->_IO_write_ptr > fp->_wide_data->_IO_read_end)
 246         fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_write_ptr;
 247     }
 248   fp->_wide_data->_IO_read_ptr = fp->_wide_data->_IO_write_ptr;
 249   fp->_wide_data->_IO_read_end = fp->_wide_data->_IO_write_ptr;
 250
 251   fp->_flags &= ~_IO_CURRENTLY_PUTTING;
 252 }
 253
 254 off64_t
 255 _IO_wstr_seekoff (FILE *fp, off64_t offset, int dir, int mode)
 256 {
 257   off64_t new_pos;
 258
 259   if (mode == 0 && (fp->_flags & _IO_TIED_PUT_GET))
 260     mode = (fp->_flags & _IO_CURRENTLY_PUTTING ? _IOS_OUTPUT : _IOS_INPUT);
 261
 262   bool was_writing = ((fp->_wide_data->_IO_write_ptr
 263                        > fp->_wide_data->_IO_write_base)
 264                      || _IO_in_put_mode (fp));
 265   if (was_writing)
 266     _IO_wstr_switch_to_get_mode (fp);
 267
 268   if (mode == 0)
 269     {
 270       new_pos = (fp->_wide_data->_IO_write_ptr
 271                  - fp->_wide_data->_IO_write_base);
 272     }
 273   else
 274     {
 275       ssize_t cur_size = _IO_wstr_count (fp);
 276       new_pos = EOF;
 277
 278       /* Move the get pointer, if requested. */
 279       if (mode & _IOS_INPUT)
 280         {
 281           ssize_t base;
 282           switch (dir)
 283             {
 284             case _IO_seek_set:
 285               base = 0;
 286               break;
 287             case _IO_seek_cur:
 288               base = (fp->_wide_data->_IO_read_ptr
 289                      - fp->_wide_data->_IO_read_base);
 290               break;
 291             default: /* case _IO_seek_end: */
 292               base = cur_size;
 293               break;
 294             }
 295           ssize_t maxval = SSIZE_MAX/sizeof (wchar_t) - base;
 296           if (offset < -base || offset > maxval)
 297             {
 298               __set_errno (EINVAL);
 299               return EOF;
 300             }
 301           base += offset;
 302           if (base > cur_size
 303               && enlarge_userbuf (fp, base, 1) != 0)
 304             return EOF;
 305           fp->_wide_data->_IO_read_ptr = (fp->_wide_data->_IO_read_base
 306                                           + base);
 307           fp->_wide_data->_IO_read_end = (fp->_wide_data->_IO_read_base
 308                                           + cur_size);
 309           new_pos = offset;
 310         }
 311
 312       /* Move the put pointer, if requested. */
 313       if (mode & _IOS_OUTPUT)
 314         {
 315           ssize_t base;
 316           switch (dir)
 317             {
 318             case _IO_seek_set:
 319               base = 0;
 320               break;
 321             case _IO_seek_cur:
 322               base = (fp->_wide_data->_IO_write_ptr
 323                      - fp->_wide_data->_IO_write_base);
 324               break;
 325             default: /* case _IO_seek_end: */
 326               base = cur_size;
 327               break;
 328             }
 329           ssize_t maxval = SSIZE_MAX/sizeof (wchar_t) - base;
 330           if (offset < -base || offset > maxval)
 331             {
 332               __set_errno (EINVAL);
 333               return EOF;
 334             }
 335           base += offset;
 336           if (base > cur_size
 337               && enlarge_userbuf (fp, base, 0) != 0)
 338             return EOF;
 339           fp->_wide_data->_IO_write_ptr = (fp->_wide_data->_IO_write_base
 340                                            + base);
 341           new_pos = base;
 342         }
 343     }
 344   return new_pos;
 345 }
 346
 347 wint_t
 348 _IO_wstr_pbackfail (FILE *fp, wint_t c)
 349 {
 350   if ((fp->_flags & _IO_NO_WRITES) && c != WEOF)
 351     return WEOF;
 352   return _IO_wdefault_pbackfail (fp, c);
 353 }
 354
 355 void
 356 _IO_wstr_finish (FILE *fp, int dummy)
 357 {
 358   if (fp->_wide_data->_IO_buf_base && !(fp->_flags2 & _IO_FLAGS2_USER_WBUF))
 359     free (fp->_wide_data->_IO_buf_base);
 360   fp->_wide_data->_IO_buf_base = NULL;
 361
 362   _IO_wdefault_finish (fp, 0);
 363 }