libio/iofopncook.c

   1 /* Copyright (C) 1993-2017 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    <http://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
  32 /* Prototyped for local functions.  */
  33 static _IO_ssize_t _IO_cookie_read (_IO_FILE* fp, void* buf,
  34                                     _IO_ssize_t size);
  35 static _IO_ssize_t _IO_cookie_write (_IO_FILE* fp,
  36                                      const void* buf, _IO_ssize_t size);
  37 static _IO_off64_t _IO_cookie_seek (_IO_FILE *fp, _IO_off64_t offset, int dir);
  38 static _IO_off64_t _IO_cookie_seekoff (_IO_FILE *fp, _IO_off64_t offset,
  39                                        int dir, int mode);
  40 static int _IO_cookie_close (_IO_FILE* fp);
  41
  42 static _IO_ssize_t
  43 _IO_cookie_read (_IO_FILE *fp, void *buf, _IO_ssize_t size)
  44 {
  45   struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;
  46   cookie_read_function_t *read_cb = cfile->__io_functions.read;
  47 #ifdef PTR_DEMANGLE
  48   PTR_DEMANGLE (read_cb);
  49 #endif
  50
  51   if (read_cb == NULL)
  52     return -1;
  53
  54   return read_cb (cfile->__cookie, buf, size);
  55 }
  56
  57 static _IO_ssize_t
  58 _IO_cookie_write (_IO_FILE *fp, const void *buf, _IO_ssize_t size)
  59 {
  60   struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;
  61   cookie_write_function_t *write_cb = cfile->__io_functions.write;
  62 #ifdef PTR_DEMANGLE
  63   PTR_DEMANGLE (write_cb);
  64 #endif
  65
  66   if (write_cb == NULL)
  67     {
  68       fp->_flags |= _IO_ERR_SEEN;
  69       return 0;
  70     }
  71
  72   _IO_ssize_t n = write_cb (cfile->__cookie, buf, size);
  73   if (n < size)
  74     fp->_flags |= _IO_ERR_SEEN;
  75
  76   return n;
  77 }
  78
  79 static _IO_off64_t
  80 _IO_cookie_seek (_IO_FILE *fp, _IO_off64_t offset, int dir)
  81 {
  82   struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;
  83   cookie_seek_function_t *seek_cb = cfile->__io_functions.seek;
  84 #ifdef PTR_DEMANGLE
  85   PTR_DEMANGLE (seek_cb);
  86 #endif
  87
  88   return ((seek_cb == NULL
  89            || (seek_cb (cfile->__cookie, &offset, dir)
  90                == -1)
  91            || offset == (_IO_off64_t) -1)
  92           ? _IO_pos_BAD : offset);
  93 }
  94
  95 static int
  96 _IO_cookie_close (_IO_FILE *fp)
  97 {
  98   struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;
  99   cookie_close_function_t *close_cb = cfile->__io_functions.close;
 100 #ifdef PTR_DEMANGLE
 101   PTR_DEMANGLE (close_cb);
 102 #endif
 103
 104   if (close_cb == NULL)
 105     return 0;
 106
 107   return close_cb (cfile->__cookie);
 108 }
 109
 110
 111 static _IO_off64_t
 112 _IO_cookie_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode)
 113 {
 114   /* We must force the fileops code to always use seek to determine
 115      the position.  */
 116   fp->_offset = _IO_pos_BAD;
 117   return _IO_file_seekoff (fp, offset, dir, mode);
 118 }
 119
 120
 121 static const struct _IO_jump_t _IO_cookie_jumps libio_vtable = {
 122   JUMP_INIT_DUMMY,
 123   JUMP_INIT(finish, _IO_file_finish),
 124   JUMP_INIT(overflow, _IO_file_overflow),
 125   JUMP_INIT(underflow, _IO_file_underflow),
 126   JUMP_INIT(uflow, _IO_default_uflow),
 127   JUMP_INIT(pbackfail, _IO_default_pbackfail),
 128   JUMP_INIT(xsputn, _IO_file_xsputn),
 129   JUMP_INIT(xsgetn, _IO_default_xsgetn),
 130   JUMP_INIT(seekoff, _IO_cookie_seekoff),
 131   JUMP_INIT(seekpos, _IO_default_seekpos),
 132   JUMP_INIT(setbuf, _IO_file_setbuf),
 133   JUMP_INIT(sync, _IO_file_sync),
 134   JUMP_INIT(doallocate, _IO_file_doallocate),
 135   JUMP_INIT(read, _IO_cookie_read),
 136   JUMP_INIT(write, _IO_cookie_write),
 137   JUMP_INIT(seek, _IO_cookie_seek),
 138   JUMP_INIT(close, _IO_cookie_close),
 139   JUMP_INIT(stat, _IO_default_stat),
 140   JUMP_INIT(showmanyc, _IO_default_showmanyc),
 141   JUMP_INIT(imbue, _IO_default_imbue),
 142 };
 143
 144
 145 /* Copy the callbacks from SOURCE to *TARGET, with pointer
 146    mangling.  */
 147 static void
 148 set_callbacks (_IO_cookie_io_functions_t *target,
 149                _IO_cookie_io_functions_t source)
 150 {
 151 #ifdef PTR_MANGLE
 152   PTR_MANGLE (source.read);
 153   PTR_MANGLE (source.write);
 154   PTR_MANGLE (source.seek);
 155   PTR_MANGLE (source.close);
 156 #endif
 157   *target = source;
 158 }
 159
 160 void
 161 _IO_cookie_init (struct _IO_cookie_file *cfile, int read_write,
 162                  void *cookie, _IO_cookie_io_functions_t io_functions)
 163 {
 164   _IO_init_internal (&cfile->__fp.file, 0);
 165   _IO_JUMPS (&cfile->__fp) = &_IO_cookie_jumps;
 166
 167   cfile->__cookie = cookie;
 168   set_callbacks (&cfile->__io_functions, io_functions);
 169
 170   _IO_new_file_init_internal (&cfile->__fp);
 171
 172   _IO_mask_flags (&cfile->__fp.file, read_write,
 173                   _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
 174
 175   /* We use a negative number different from -1 for _fileno to mark that
 176      this special stream is not associated with a real file, but still has
 177      to be treated as such.  */
 178   cfile->__fp.file._fileno = -2;
 179 }
 180
 181
 182 _IO_FILE *
 183 _IO_fopencookie (void *cookie, const char *mode,
 184                  _IO_cookie_io_functions_t io_functions)
 185 {
 186   int read_write;
 187   struct locked_FILE
 188   {
 189     struct _IO_cookie_file cfile;
 190 #ifdef _IO_MTSAFE_IO
 191     _IO_lock_t lock;
 192 #endif
 193   } *new_f;
 194
 195   switch (*mode++)
 196     {
 197     case 'r':
 198       read_write = _IO_NO_WRITES;
 199       break;
 200     case 'w':
 201       read_write = _IO_NO_READS;
 202       break;
 203     case 'a':
 204       read_write = _IO_NO_READS|_IO_IS_APPENDING;
 205       break;
 206     default:
 207       __set_errno (EINVAL);
 208       return NULL;
 209   }
 210   if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
 211     read_write &= _IO_IS_APPENDING;
 212
 213   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
 214   if (new_f == NULL)
 215     return NULL;
 216 #ifdef _IO_MTSAFE_IO
 217   new_f->cfile.__fp.file._lock = &new_f->lock;
 218 #endif
 219
 220   _IO_cookie_init (&new_f->cfile, read_write, cookie, io_functions);
 221
 222   return (_IO_FILE *) &new_f->cfile.__fp;
 223 }
 224
 225 versioned_symbol (libc, _IO_fopencookie, fopencookie, GLIBC_2_2);
 226
 227 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
 228
 229 static _IO_off64_t _IO_old_cookie_seek (_IO_FILE *fp, _IO_off64_t offset,
 230                                         int dir);
 231 _IO_FILE * _IO_old_fopencookie (void *cookie, const char *mode,
 232                                 _IO_cookie_io_functions_t io_functions);
 233
 234 static _IO_off64_t
 235 attribute_compat_text_section
 236 _IO_old_cookie_seek (_IO_FILE *fp, _IO_off64_t offset, int dir)
 237 {
 238   struct _IO_cookie_file *cfile = (struct _IO_cookie_file *) fp;
 239   int (*seek_cb) (_IO_FILE *, _IO_off_t, int)
 240     = (int (*) (_IO_FILE *, _IO_off_t, int)) cfile->__io_functions.seek;;
 241 #ifdef PTR_DEMANGLE
 242   PTR_DEMANGLE (seek_cb);
 243 #endif
 244
 245   if (seek_cb == NULL)
 246     return _IO_pos_BAD;
 247
 248   int ret = seek_cb (cfile->__cookie, offset, dir);
 249
 250   return (ret == -1) ? _IO_pos_BAD : ret;
 251 }
 252
 253 static const struct _IO_jump_t _IO_old_cookie_jumps libio_vtable = {
 254   JUMP_INIT_DUMMY,
 255   JUMP_INIT(finish, _IO_file_finish),
 256   JUMP_INIT(overflow, _IO_file_overflow),
 257   JUMP_INIT(underflow, _IO_file_underflow),
 258   JUMP_INIT(uflow, _IO_default_uflow),
 259   JUMP_INIT(pbackfail, _IO_default_pbackfail),
 260   JUMP_INIT(xsputn, _IO_file_xsputn),
 261   JUMP_INIT(xsgetn, _IO_default_xsgetn),
 262   JUMP_INIT(seekoff, _IO_cookie_seekoff),
 263   JUMP_INIT(seekpos, _IO_default_seekpos),
 264   JUMP_INIT(setbuf, _IO_file_setbuf),
 265   JUMP_INIT(sync, _IO_file_sync),
 266   JUMP_INIT(doallocate, _IO_file_doallocate),
 267   JUMP_INIT(read, _IO_cookie_read),
 268   JUMP_INIT(write, _IO_cookie_write),
 269   JUMP_INIT(seek, _IO_old_cookie_seek),
 270   JUMP_INIT(close, _IO_cookie_close),
 271   JUMP_INIT(stat, _IO_default_stat),
 272   JUMP_INIT(showmanyc, _IO_default_showmanyc),
 273   JUMP_INIT(imbue, _IO_default_imbue),
 274 };
 275
 276 _IO_FILE *
 277 attribute_compat_text_section
 278 _IO_old_fopencookie (void *cookie, const char *mode,
 279                      _IO_cookie_io_functions_t io_functions)
 280 {
 281   _IO_FILE *ret;
 282
 283   ret = _IO_fopencookie (cookie, mode, io_functions);
 284   if (ret != NULL)
 285     _IO_JUMPS_FILE_plus (ret) = &_IO_old_cookie_jumps;
 286
 287   return ret;
 288 }
 289
 290 compat_symbol (libc, _IO_old_fopencookie, fopencookie, GLIBC_2_0);
 291
 292 #endif