root/main/streams/cast.c

DEFINITIONS

1. fopencookie
2. stream_cookie_reader
3. stream_cookie_writer
4. stream_cookie_seeker
5. stream_cookie_closer
6. stream_cookie_reader
7. stream_cookie_writer
8. stream_cookie_seeker
9. stream_cookie_seeker
10. stream_cookie_closer
11. php_stream_mode_sanitize_fdopen_fopencookie
12. _php_stream_cast
13. _php_stream_open_wrapper_as_file
14. _php_stream_make_seekable

   1 /*
   2    +----------------------------------------------------------------------+
   3    | PHP Version 7                                                        |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 1997-2016 The PHP Group                                |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15    | Authors: Wez Furlong <wez@thebrainroom.com>                          |
  16    +----------------------------------------------------------------------+
  17  */
  18 
  19 /* $Id$ */
  20 
  21 #define _GNU_SOURCE
  22 #include "php.h"
  23 #include "php_globals.h"
  24 #include "php_network.h"
  25 #include "php_open_temporary_file.h"
  26 #include "ext/standard/file.h"
  27 #include <stddef.h>
  28 #include <fcntl.h>
  29 
  30 #include "php_streams_int.h"
  31 
  32 /* Under BSD, emulate fopencookie using funopen */
  33 #if defined(HAVE_FUNOPEN) && !defined(HAVE_FOPENCOOKIE)
  34 
  35 /* NetBSD 6.0+ uses off_t instead of fpos_t in funopen */
  36 # if defined(__NetBSD__) && (__NetBSD_Version__ >= 600000000)
  37 #  define PHP_FPOS_T off_t
  38 # else
  39 #  define PHP_FPOS_T fpos_t
  40 # endif
  41 
  42 typedef struct {
  43         int (*reader)(void *, char *, int);
  44         int (*writer)(void *, const char *, int);
  45         PHP_FPOS_T (*seeker)(void *, PHP_FPOS_T, int);
  46         int (*closer)(void *);
  47 } COOKIE_IO_FUNCTIONS_T;
  48 
  49 FILE *fopencookie(void *cookie, const char *mode, COOKIE_IO_FUNCTIONS_T *funcs)
  50 {
  51         return funopen(cookie, funcs->reader, funcs->writer, funcs->seeker, funcs->closer);
  52 }
  53 # define HAVE_FOPENCOOKIE 1
  54 # define PHP_EMULATE_FOPENCOOKIE 1
  55 # define PHP_STREAM_COOKIE_FUNCTIONS    &stream_cookie_functions
  56 #elif defined(HAVE_FOPENCOOKIE)
  57 # define PHP_STREAM_COOKIE_FUNCTIONS    stream_cookie_functions
  58 #endif
  59 
  60 /* {{{ STDIO with fopencookie */
  61 #if defined(PHP_EMULATE_FOPENCOOKIE)
  62 /* use our fopencookie emulation */
  63 static int stream_cookie_reader(void *cookie, char *buffer, int size)
  64 {
  65         int ret;
  66 
  67         ret = php_stream_read((php_stream*)cookie, buffer, size);
  68         return ret;
  69 }
  70 
  71 static int stream_cookie_writer(void *cookie, const char *buffer, int size)
  72 {
  73 
  74         return php_stream_write((php_stream *)cookie, (char *)buffer, size);
  75 }
  76 
  77 static PHP_FPOS_T stream_cookie_seeker(void *cookie, zend_off_t position, int whence)
  78 {
  79 
  80         return (PHP_FPOS_T)php_stream_seek((php_stream *)cookie, position, whence);
  81 }
  82 
  83 static int stream_cookie_closer(void *cookie)
  84 {
  85         php_stream *stream = (php_stream*)cookie;
  86 
  87         /* prevent recursion */
  88         stream->fclose_stdiocast = PHP_STREAM_FCLOSE_NONE;
  89         return php_stream_free(stream, PHP_STREAM_FREE_CLOSE | PHP_STREAM_FREE_KEEP_RSRC);
  90 }
  91 #elif defined(HAVE_FOPENCOOKIE)
  92 static ssize_t stream_cookie_reader(void *cookie, char *buffer, size_t size)
  93 {
  94         ssize_t ret;
  95 
  96         ret = php_stream_read(((php_stream *)cookie), buffer, size);
  97         return ret;
  98 }
  99 
 100 static ssize_t stream_cookie_writer(void *cookie, const char *buffer, size_t size)
 101 {
 102 
 103         return php_stream_write(((php_stream *)cookie), (char *)buffer, size);
 104 }
 105 
 106 # ifdef COOKIE_SEEKER_USES_OFF64_T
 107 static int stream_cookie_seeker(void *cookie, __off64_t *position, int whence)
 108 {
 109 
 110         *position = php_stream_seek((php_stream *)cookie, (zend_off_t)*position, whence);
 111 
 112         if (*position == -1) {
 113                 return -1;
 114         }
 115         return 0;
 116 }
 117 # else
 118 static int stream_cookie_seeker(void *cookie, zend_off_t position, int whence)
 119 {
 120 
 121         return php_stream_seek((php_stream *)cookie, position, whence);
 122 }
 123 # endif
 124 
 125 static int stream_cookie_closer(void *cookie)
 126 {
 127         php_stream *stream = (php_stream*)cookie;
 128 
 129         /* prevent recursion */
 130         stream->fclose_stdiocast = PHP_STREAM_FCLOSE_NONE;
 131         return php_stream_free(stream, PHP_STREAM_FREE_CLOSE | PHP_STREAM_FREE_KEEP_RSRC);
 132 }
 133 #endif /* elif defined(HAVE_FOPENCOOKIE) */
 134 
 135 #if HAVE_FOPENCOOKIE
 136 static COOKIE_IO_FUNCTIONS_T stream_cookie_functions =
 137 {
 138         stream_cookie_reader, stream_cookie_writer,
 139         stream_cookie_seeker, stream_cookie_closer
 140 };
 141 #else
 142 /* TODO: use socketpair() to emulate fopencookie, as suggested by Hartmut ? */
 143 #endif
 144 /* }}} */
 145 
 146 /* {{{ php_stream_mode_sanitize_fdopen_fopencookie
 147  * Result should have at least size 5, e.g. to write wbx+\0 */
 148 void php_stream_mode_sanitize_fdopen_fopencookie(php_stream *stream, char *result)
 149 {
 150         /* replace modes not supported by fdopen and fopencookie, but supported
 151          * by PHP's fread(), so that their calls won't fail */
 152         const char *cur_mode = stream->mode;
 153         int         has_plus = 0,
 154                         has_bin  = 0,
 155                                 i,
 156                                 res_curs = 0;
 157 
 158         if (cur_mode[0] == 'r' || cur_mode[0] == 'w' || cur_mode[0] == 'a') {
 159                 result[res_curs++] = cur_mode[0];
 160         } else {
 161                 /* assume cur_mode[0] is 'c' or 'x'; substitute by 'w', which should not
 162                  * truncate anything in fdopen/fopencookie */
 163                 result[res_curs++] = 'w';
 164 
 165                 /* x is allowed (at least by glibc & compat), but not as the 1st mode
 166                  * as in PHP and in any case is (at best) ignored by fdopen and fopencookie */
 167         }
 168 
 169         /* assume current mode has at most length 4 (e.g. wbn+) */
 170         for (i = 1; i < 4 && cur_mode[i] != '\0'; i++) {
 171                 if (cur_mode[i] == 'b') {
 172                         has_bin = 1;
 173                 } else if (cur_mode[i] == '+') {
 174                         has_plus = 1;
 175                 }
 176                 /* ignore 'n', 't' or other stuff */
 177         }
 178 
 179         if (has_bin) {
 180                 result[res_curs++] = 'b';
 181         }
 182         if (has_plus) {
 183                 result[res_curs++] = '+';
 184         }
 185 
 186         result[res_curs] = '\0';
 187 }
 188 /* }}} */
 189 
 190 /* {{{ php_stream_cast */
 191 PHPAPI int _php_stream_cast(php_stream *stream, int castas, void **ret, int show_err)
 192 {
 193         int flags = castas & PHP_STREAM_CAST_MASK;
 194         castas &= ~PHP_STREAM_CAST_MASK;
 195 
 196         /* synchronize our buffer (if possible) */
 197         if (ret && castas != PHP_STREAM_AS_FD_FOR_SELECT) {
 198                 php_stream_flush(stream);
 199                 if (stream->ops->seek && (stream->flags & PHP_STREAM_FLAG_NO_SEEK) == 0) {
 200                         zend_off_t dummy;
 201 
 202                         stream->ops->seek(stream, stream->position, SEEK_SET, &dummy);
 203                         stream->readpos = stream->writepos = 0;
 204                 }
 205         }
 206 
 207         /* filtered streams can only be cast as stdio, and only when fopencookie is present */
 208 
 209         if (castas == PHP_STREAM_AS_STDIO) {
 210                 if (stream->stdiocast) {
 211                         if (ret) {
 212                                 *(FILE**)ret = stream->stdiocast;
 213                         }
 214                         goto exit_success;
 215                 }
 216 
 217                 /* if the stream is a stdio stream let's give it a chance to respond
 218                  * first, to avoid doubling up the layers of stdio with an fopencookie */
 219                 if (php_stream_is(stream, PHP_STREAM_IS_STDIO) &&
 220                         stream->ops->cast &&
 221                         !php_stream_is_filtered(stream) &&
 222                         stream->ops->cast(stream, castas, ret) == SUCCESS
 223                 ) {
 224                         goto exit_success;
 225                 }
 226 
 227 #if HAVE_FOPENCOOKIE
 228                 /* if just checking, say yes we can be a FILE*, but don't actually create it yet */
 229                 if (ret == NULL) {
 230                         goto exit_success;
 231                 }
 232 
 233                 {
 234                         char fixed_mode[5];
 235                         php_stream_mode_sanitize_fdopen_fopencookie(stream, fixed_mode);
 236                         *(FILE**)ret = fopencookie(stream, fixed_mode, PHP_STREAM_COOKIE_FUNCTIONS);
 237                 }
 238 
 239                 if (*ret != NULL) {
 240                         zend_off_t pos;
 241 
 242                         stream->fclose_stdiocast = PHP_STREAM_FCLOSE_FOPENCOOKIE;
 243 
 244                         /* If the stream position is not at the start, we need to force
 245                          * the stdio layer to believe it's real location. */
 246                         pos = php_stream_tell(stream);
 247                         if (pos > 0) {
 248                                 zend_fseek(*ret, pos, SEEK_SET);
 249                         }
 250 
 251                         goto exit_success;
 252                 }
 253 
 254                 /* must be either:
 255                         a) programmer error
 256                         b) no memory
 257                         -> lets bail
 258                 */
 259                 php_error_docref(NULL, E_ERROR, "fopencookie failed");
 260                 return FAILURE;
 261 #endif
 262 
 263                 if (!php_stream_is_filtered(stream) && stream->ops->cast && stream->ops->cast(stream, castas, NULL) == SUCCESS) {
 264                         if (FAILURE == stream->ops->cast(stream, castas, ret)) {
 265                                 return FAILURE;
 266                         }
 267                         goto exit_success;
 268                 } else if (flags & PHP_STREAM_CAST_TRY_HARD) {
 269                         php_stream *newstream;
 270 
 271                         newstream = php_stream_fopen_tmpfile();
 272                         if (newstream) {
 273                                 int retcopy = php_stream_copy_to_stream_ex(stream, newstream, PHP_STREAM_COPY_ALL, NULL);
 274 
 275                                 if (retcopy != SUCCESS) {
 276                                         php_stream_close(newstream);
 277                                 } else {
 278                                         int retcast = php_stream_cast(newstream, castas | flags, (void **)ret, show_err);
 279 
 280                                         if (retcast == SUCCESS) {
 281                                                 rewind(*(FILE**)ret);
 282                                         }
 283 
 284                                         /* do some specialized cleanup */
 285                                         if ((flags & PHP_STREAM_CAST_RELEASE)) {
 286                                                 php_stream_free(stream, PHP_STREAM_FREE_CLOSE_CASTED);
 287                                         }
 288 
 289                                         /* TODO: we probably should be setting .stdiocast and .fclose_stdiocast or
 290                                          * we may be leaking the FILE*. Needs investigation, though. */
 291                                         return retcast;
 292                                 }
 293                         }
 294                 }
 295         }
 296 
 297         if (php_stream_is_filtered(stream)) {
 298                 php_error_docref(NULL, E_WARNING, "cannot cast a filtered stream on this system");
 299                 return FAILURE;
 300         } else if (stream->ops->cast && stream->ops->cast(stream, castas, ret) == SUCCESS) {
 301                 goto exit_success;
 302         }
 303 
 304         if (show_err) {
 305                 /* these names depend on the values of the PHP_STREAM_AS_XXX defines in php_streams.h */
 306                 static const char *cast_names[4] = {
 307                         "STDIO FILE*",
 308                         "File Descriptor",
 309                         "Socket Descriptor",
 310                         "select()able descriptor"
 311                 };
 312 
 313                 php_error_docref(NULL, E_WARNING, "cannot represent a stream of type %s as a %s", stream->ops->label, cast_names[castas]);
 314         }
 315 
 316         return FAILURE;
 317 
 318 exit_success:
 319 
 320         if ((stream->writepos - stream->readpos) > 0 &&
 321                 stream->fclose_stdiocast != PHP_STREAM_FCLOSE_FOPENCOOKIE &&
 322                 (flags & PHP_STREAM_CAST_INTERNAL) == 0
 323         ) {
 324                 /* the data we have buffered will be lost to the third party library that
 325                  * will be accessing the stream.  Emit a warning so that the end-user will
 326                  * know that they should try something else */
 327 
 328                 php_error_docref(NULL, E_WARNING, ZEND_LONG_FMT " bytes of buffered data lost during stream conversion!", (zend_long)(stream->writepos - stream->readpos));
 329         }
 330 
 331         if (castas == PHP_STREAM_AS_STDIO && ret) {
 332                 stream->stdiocast = *(FILE**)ret;
 333         }
 334 
 335         if (flags & PHP_STREAM_CAST_RELEASE) {
 336                 php_stream_free(stream, PHP_STREAM_FREE_CLOSE_CASTED);
 337         }
 338 
 339         return SUCCESS;
 340 
 341 }
 342 /* }}} */
 343 
 344 /* {{{ php_stream_open_wrapper_as_file */
 345 PHPAPI FILE * _php_stream_open_wrapper_as_file(char *path, char *mode, int options, zend_string **opened_path STREAMS_DC)
 346 {
 347         FILE *fp = NULL;
 348         php_stream *stream = NULL;
 349 
 350         stream = php_stream_open_wrapper_rel(path, mode, options|STREAM_WILL_CAST, opened_path);
 351 
 352         if (stream == NULL) {
 353                 return NULL;
 354         }
 355 
 356         if (php_stream_cast(stream, PHP_STREAM_AS_STDIO|PHP_STREAM_CAST_TRY_HARD|PHP_STREAM_CAST_RELEASE, (void**)&fp, REPORT_ERRORS) == FAILURE) {
 357                 php_stream_close(stream);
 358                 if (opened_path && *opened_path) {
 359                         zend_string_release(*opened_path);
 360                 }
 361                 return NULL;
 362         }
 363         return fp;
 364 }
 365 /* }}} */
 366 
 367 /* {{{ php_stream_make_seekable */
 368 PHPAPI int _php_stream_make_seekable(php_stream *origstream, php_stream **newstream, int flags STREAMS_DC)
 369 {
 370         if (newstream == NULL) {
 371                 return PHP_STREAM_FAILED;
 372         }
 373         *newstream = NULL;
 374 
 375         if (((flags & PHP_STREAM_FORCE_CONVERSION) == 0) && origstream->ops->seek != NULL) {
 376                 *newstream = origstream;
 377                 return PHP_STREAM_UNCHANGED;
 378         }
 379 
 380         /* Use a tmpfile and copy the old streams contents into it */
 381 
 382         if (flags & PHP_STREAM_PREFER_STDIO) {
 383                 *newstream = php_stream_fopen_tmpfile();
 384         } else {
 385                 *newstream = php_stream_temp_new();
 386         }
 387 
 388         if (*newstream == NULL) {
 389                 return PHP_STREAM_FAILED;
 390         }
 391 
 392 #if ZEND_DEBUG
 393         (*newstream)->open_filename = origstream->open_filename;
 394         (*newstream)->open_lineno = origstream->open_lineno;
 395 #endif
 396 
 397         if (php_stream_copy_to_stream_ex(origstream, *newstream, PHP_STREAM_COPY_ALL, NULL) != SUCCESS) {
 398                 php_stream_close(*newstream);
 399                 *newstream = NULL;
 400                 return PHP_STREAM_CRITICAL;
 401         }
 402 
 403         php_stream_close(origstream);
 404         php_stream_seek(*newstream, 0, SEEK_SET);
 405 
 406         return PHP_STREAM_RELEASED;
 407 }
 408 /* }}} */
 409 
 410 /*
 411  * Local variables:
 412  * tab-width: 4
 413  * c-basic-offset: 4
 414  * End:
 415  * vim600: noet sw=4 ts=4 fdm=marker
 416  * vim<600: noet sw=4 ts=4
 417  */