libio/iofopncook.c

   1 /* Copyright (C) 1993-2023 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    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 <libioP.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <shlib-compat.h>
  31 #include <pointer_guard.h>
  32
  33 static ssize_t
  34 _IO_cookie_read (FILE *fp, void *buf, ssize_t size)
  35 {
  36   struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;
  37   cookie_read_function_t *read_cb = cfile->__io_functions.read;
  38   PTR_DEMANGLE (read_cb);
  39
  40   if (read_cb == NULL)
  41     return -1;
  42
  43   return read_cb (cfile->__cookie, buf, size);
  44 }
  45
  46 static ssize_t
  47 _IO_cookie_write (FILE *fp, const void *buf, ssize_t size)
  48 {
  49   struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;
  50   cookie_write_function_t *write_cb = cfile->__io_functions.write;
  51   PTR_DEMANGLE (write_cb);
  52
  53   if (write_cb == NULL)
  54     {
  55       fp->_flags |= _IO_ERR_SEEN;
  56       return 0;
  57     }
  58
  59   ssize_t n = write_cb (cfile->__cookie, buf, size);
  60   if (n < size)
  61     fp->_flags |= _IO_ERR_SEEN;
  62
  63   return n;
  64 }
  65
  66 static off64_t
  67 _IO_cookie_seek (FILE *fp, off64_t offset, int dir)
  68 {
  69   struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;
  70   cookie_seek_function_t *seek_cb = cfile->__io_functions.seek;
  71   PTR_DEMANGLE (seek_cb);
  72
  73   return ((seek_cb == NULL
  74            || (seek_cb (cfile->__cookie, &offset, dir)
  75                == -1)
  76            || offset == (off64_t) -1)
  77           ? _IO_pos_BAD : offset);
  78 }
  79
  80 static int
  81 _IO_cookie_close (FILE *fp)
  82 {
  83   struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;
  84   cookie_close_function_t *close_cb = cfile->__io_functions.close;
  85   PTR_DEMANGLE (close_cb);
  86
  87   if (close_cb == NULL)
  88     return 0;
  89
  90   return close_cb (cfile->__cookie);
  91 }
  92
  93
  94 static off64_t
  95 _IO_cookie_seekoff (FILE *fp, off64_t offset, int dir, int mode)
  96 {
  97   /* We must force the fileops code to always use seek to determine
  98      the position.  */
  99   fp->_offset = _IO_pos_BAD;
 100   return _IO_file_seekoff (fp, offset, dir, mode);
 101 }
 102
 103
 104 static const struct _IO_jump_t _IO_cookie_jumps libio_vtable = {
 105   JUMP_INIT_DUMMY,
 106   JUMP_INIT(finish, _IO_file_finish),
 107   JUMP_INIT(overflow, _IO_file_overflow),
 108   JUMP_INIT(underflow, _IO_file_underflow),
 109   JUMP_INIT(uflow, _IO_default_uflow),
 110   JUMP_INIT(pbackfail, _IO_default_pbackfail),
 111   JUMP_INIT(xsputn, _IO_file_xsputn),
 112   JUMP_INIT(xsgetn, _IO_default_xsgetn),
 113   JUMP_INIT(seekoff, _IO_cookie_seekoff),
 114   JUMP_INIT(seekpos, _IO_default_seekpos),
 115   JUMP_INIT(setbuf, _IO_file_setbuf),
 116   JUMP_INIT(sync, _IO_file_sync),
 117   JUMP_INIT(doallocate, _IO_file_doallocate),
 118   JUMP_INIT(read, _IO_cookie_read),
 119   JUMP_INIT(write, _IO_cookie_write),
 120   JUMP_INIT(seek, _IO_cookie_seek),
 121   JUMP_INIT(close, _IO_cookie_close),
 122   JUMP_INIT(stat, _IO_default_stat),
 123   JUMP_INIT(showmanyc, _IO_default_showmanyc),
 124   JUMP_INIT(imbue, _IO_default_imbue),
 125 };
 126
 127
 128 /* Copy the callbacks from SOURCE to *TARGET, with pointer
 129    mangling.  */
 130 static void
 131 set_callbacks (cookie_io_functions_t *target,
 132                cookie_io_functions_t source)
 133 {
 134   PTR_MANGLE (source.read);
 135   PTR_MANGLE (source.write);
 136   PTR_MANGLE (source.seek);
 137   PTR_MANGLE (source.close);
 138   *target = source;
 139 }
 140
 141 void
 142 _IO_cookie_init (struct _IO_cookie_file *cfile, int read_write,
 143                  void *cookie, cookie_io_functions_t io_functions)
 144 {
 145   _IO_init_internal (&cfile->__fp.file, 0);
 146   _IO_JUMPS (&cfile->__fp) = &_IO_cookie_jumps;
 147
 148   cfile->__cookie = cookie;
 149   set_callbacks (&cfile->__io_functions, io_functions);
 150
 151   _IO_new_file_init_internal (&cfile->__fp);
 152
 153   _IO_mask_flags (&cfile->__fp.file, read_write,
 154                   _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
 155
 156   cfile->__fp.file._flags2 |= _IO_FLAGS2_NEED_LOCK;
 157
 158   /* We use a negative number different from -1 for _fileno to mark that
 159      this special stream is not associated with a real file, but still has
 160      to be treated as such.  */
 161   cfile->__fp.file._fileno = -2;
 162 }
 163
 164
 165 FILE *
 166 _IO_fopencookie (void *cookie, const char *mode,
 167                  cookie_io_functions_t io_functions)
 168 {
 169   int read_write;
 170   struct locked_FILE
 171   {
 172     struct _IO_cookie_file cfile;
 173 #ifdef _IO_MTSAFE_IO
 174     _IO_lock_t lock;
 175 #endif
 176   } *new_f;
 177
 178   switch (*mode++)
 179     {
 180     case 'r':
 181       read_write = _IO_NO_WRITES;
 182       break;
 183     case 'w':
 184       read_write = _IO_NO_READS;
 185       break;
 186     case 'a':
 187       read_write = _IO_NO_READS|_IO_IS_APPENDING;
 188       break;
 189     default:
 190       __set_errno (EINVAL);
 191       return NULL;
 192   }
 193   if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
 194     read_write &= _IO_IS_APPENDING;
 195
 196   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 197   if (new_f == NULL)
 198     return NULL;
 199 #ifdef _IO_MTSAFE_IO
 200   new_f->cfile.__fp.file._lock = &new_f->lock;
 201 #endif
 202
 203   _IO_cookie_init (&new_f->cfile, read_write, cookie, io_functions);
 204
 205   return (FILE *) &new_f->cfile.__fp;
 206 }
 207
 208 versioned_symbol (libc, _IO_fopencookie, fopencookie, GLIBC_2_2);
 209
 210 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
 211
 212 static off64_t
 213 attribute_compat_text_section
 214 _IO_old_cookie_seek (FILE *fp, off64_t offset, int dir)
 215 {
 216   struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;
 217   int (*seek_cb) (FILE *, off_t, int)
 218     = (int (*) (FILE *, off_t, int)) cfile->__io_functions.seek;
 219   PTR_DEMANGLE (seek_cb);
 220
 221   if (seek_cb == NULL)
 222     return _IO_pos_BAD;
 223
 224   int ret = seek_cb (cfile->__cookie, offset, dir);
 225
 226   return (ret == -1) ? _IO_pos_BAD : ret;
 227 }
 228
 229 static const struct _IO_jump_t _IO_old_cookie_jumps libio_vtable = {
 230   JUMP_INIT_DUMMY,
 231   JUMP_INIT(finish, _IO_file_finish),
 232   JUMP_INIT(overflow, _IO_file_overflow),
 233   JUMP_INIT(underflow, _IO_file_underflow),
 234   JUMP_INIT(uflow, _IO_default_uflow),
 235   JUMP_INIT(pbackfail, _IO_default_pbackfail),
 236   JUMP_INIT(xsputn, _IO_file_xsputn),
 237   JUMP_INIT(xsgetn, _IO_default_xsgetn),
 238   JUMP_INIT(seekoff, _IO_cookie_seekoff),
 239   JUMP_INIT(seekpos, _IO_default_seekpos),
 240   JUMP_INIT(setbuf, _IO_file_setbuf),
 241   JUMP_INIT(sync, _IO_file_sync),
 242   JUMP_INIT(doallocate, _IO_file_doallocate),
 243   JUMP_INIT(read, _IO_cookie_read),
 244   JUMP_INIT(write, _IO_cookie_write),
 245   JUMP_INIT(seek, _IO_old_cookie_seek),
 246   JUMP_INIT(close, _IO_cookie_close),
 247   JUMP_INIT(stat, _IO_default_stat),
 248   JUMP_INIT(showmanyc, _IO_default_showmanyc),
 249   JUMP_INIT(imbue, _IO_default_imbue),
 250 };
 251
 252 FILE *
 253 attribute_compat_text_section
 254 _IO_old_fopencookie (void *cookie, const char *mode,
 255                      cookie_io_functions_t io_functions)
 256 {
 257   FILE *ret;
 258
 259   ret = _IO_fopencookie (cookie, mode, io_functions);
 260   if (ret != NULL)
 261     _IO_JUMPS_FILE_plus (ret) = &_IO_old_cookie_jumps;
 262
 263   return ret;
 264 }
 265
 266 compat_symbol (libc, _IO_old_fopencookie, fopencookie, GLIBC_2_0);
 267
 268 #endif