assuan/assuan-buffer.c

   1 /* assuan-buffer.c - read and send data
   2  * Copyright (C) 2001, 2002, 2003, 2004, 2006 Free Software Foundation, Inc.
   3  *
   4  * This file is part of Assuan.
   5  *
   6  * Assuan is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as
   8  * published by the Free Software Foundation; either version 2.1 of
   9  * the License, or (at your option) any later version.
  10  *
  11  * Assuan is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <stdio.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <assert.h>
  27 #ifdef HAVE_W32_SYSTEM
  28 #include <process.h>
  29 #endif
  30 #include "assuan-defs.h"
  31
  32
  33 /* Extended version of write(2) to guarantee that all bytes are
  34    written.  Returns 0 on success or -1 and ERRNO on failure. */
  35 static int
  36 writen (assuan_context_t ctx, const char *buffer, size_t length)
  37 {
  38   while (length)
  39     {
  40       ssize_t nwritten = ctx->io->writefnc (ctx, buffer, length);
  41
  42       if (nwritten < 0)
  43         {
  44           if (errno == EINTR)
  45             continue;
  46           return -1; /* write error */
  47         }
  48       length -= nwritten;
  49       buffer += nwritten;
  50     }
  51   return 0;  /* okay */
  52 }
  53
  54 /* Read an entire line. Returns 0 on success or -1 and ERRNO on
  55    failure.  EOF is indictated by setting the integer at address
  56    R_EOF.  Note: BUF, R_NREAD and R_EOF contain a valid result even if
  57    an error is returned.  */
  58 static int
  59 readline (assuan_context_t ctx, char *buf, size_t buflen,
  60           int *r_nread, int *r_eof)
  61 {
  62   size_t nleft = buflen;
  63   char *p;
  64
  65   *r_eof = 0;
  66   *r_nread = 0;
  67   while (nleft > 0)
  68     {
  69       ssize_t n = ctx->io->readfnc (ctx, buf, nleft);
  70
  71       if (n < 0)
  72         {
  73           if (errno == EINTR)
  74             continue;
  75           return -1; /* read error */
  76         }
  77       else if (!n)
  78         {
  79           *r_eof = 1;
  80           break; /* allow incomplete lines */
  81         }
  82       p = buf;
  83       nleft -= n;
  84       buf += n;
  85       *r_nread += n;
  86
  87       p = memrchr (p, '\n', n);
  88       if (p)
  89         break; /* at least one full line available - that's enough for now */
  90     }
  91
  92   return 0;
  93 }
  94
  95
  96 /* Function returns an Assuan error.  */
  97 assuan_error_t
  98 _assuan_read_line (assuan_context_t ctx)
  99 {
 100   char *line = ctx->inbound.line;
 101   int nread, atticlen;
 102   int rc;
 103   char *endp = 0;
 104
 105   if (ctx->inbound.eof)
 106     return _assuan_error (-1);
 107
 108   atticlen = ctx->inbound.attic.linelen;
 109   if (atticlen)
 110     {
 111       memcpy (line, ctx->inbound.attic.line, atticlen);
 112       ctx->inbound.attic.linelen = 0;
 113
 114       endp = memchr (line, '\n', atticlen);
 115       if (endp)
 116         /* Found another line in the attic.  */
 117         {
 118           rc = 0;
 119           nread = atticlen;
 120           atticlen = 0;
 121         }
 122       else
 123         /* There is pending data but not a full line.  */
 124         {
 125           assert (atticlen < LINELENGTH);
 126           rc = readline (ctx, line + atticlen,
 127                          LINELENGTH - atticlen, &nread, &ctx->inbound.eof);
 128         }
 129     }
 130   else
 131     /* No pending data.  */
 132     rc = readline (ctx, line, LINELENGTH,
 133                    &nread, &ctx->inbound.eof);
 134   if (rc)
 135     {
 136       int saved_errno = errno;
 137
 138       if (ctx->log_fp)
 139         fprintf (ctx->log_fp, "%s[%u.%d] DBG: <- [Error: %s]\n",
 140                  assuan_get_assuan_log_prefix (),
 141                  (unsigned int)getpid (), (int)ctx->inbound.fd,
 142                  strerror (errno));
 143
 144       if (saved_errno == EAGAIN)
 145         {
 146           /* We have to save a partial line.  */
 147           memcpy (ctx->inbound.attic.line, line, atticlen + nread);
 148           ctx->inbound.attic.pending = 0;
 149           ctx->inbound.attic.linelen = atticlen + nread;
 150         }
 151
 152       errno = saved_errno;
 153       return _assuan_error (ASSUAN_Read_Error);
 154     }
 155   if (!nread)
 156     {
 157       assert (ctx->inbound.eof);
 158       if (ctx->log_fp)
 159         fprintf (ctx->log_fp, "%s[%u.%d] DBG: <- [EOF]\n",
 160                  assuan_get_assuan_log_prefix (),
 161                  (unsigned int)getpid (), (int)ctx->inbound.fd);
 162       return _assuan_error (-1);
 163     }
 164
 165   ctx->inbound.attic.pending = 0;
 166   nread += atticlen;
 167
 168   if (! endp)
 169     endp = memchr (line, '\n', nread);
 170
 171   if (endp)
 172     {
 173       unsigned monitor_result;
 174       int n = endp - line + 1;
 175
 176       if (n < nread)
 177         /* LINE contains more than one line.  We copy it to the attic
 178            now as handlers are allowed to modify the passed
 179            buffer.  */
 180         {
 181           int len = nread - n;
 182           memcpy (ctx->inbound.attic.line, endp + 1, len);
 183           ctx->inbound.attic.pending = memrchr (endp + 1, '\n', len) ? 1 : 0;
 184           ctx->inbound.attic.linelen = len;
 185         }
 186
 187       if (endp != line && endp[-1] == '\r')
 188         endp --;
 189       *endp = 0;
 190
 191       ctx->inbound.linelen = endp - line;
 192
 193       monitor_result = (ctx->io_monitor
 194                         ? ctx->io_monitor (ctx, 0,
 195                                            ctx->inbound.line,
 196                                            ctx->inbound.linelen)
 197                         : 0);
 198       if ( (monitor_result & 2) )
 199         ctx->inbound.linelen = 0;
 200
 201       if (ctx->log_fp && !(monitor_result & 1))
 202         {
 203           fprintf (ctx->log_fp, "%s[%u.%d] DBG: <- ",
 204                    assuan_get_assuan_log_prefix (),
 205                    (unsigned int)getpid (), (int)ctx->inbound.fd);
 206           if (ctx->confidential)
 207             fputs ("[Confidential data not shown]", ctx->log_fp);
 208           else
 209             _assuan_log_print_buffer (ctx->log_fp,
 210                                       ctx->inbound.line,
 211                                       ctx->inbound.linelen);
 212           putc ('\n', ctx->log_fp);
 213         }
 214       return 0;
 215     }
 216   else
 217     {
 218       if (ctx->log_fp)
 219         fprintf (ctx->log_fp, "%s[%u.%d] DBG: <- [Invalid line]\n",
 220                  assuan_get_assuan_log_prefix (),
 221                  (unsigned int)getpid (), (int)ctx->inbound.fd);
 222       *line = 0;
 223       ctx->inbound.linelen = 0;
 224       return _assuan_error (ctx->inbound.eof
 225                             ? ASSUAN_Line_Not_Terminated
 226                             : ASSUAN_Line_Too_Long);
 227     }
 228 }
 229
 230
 231 /* Read the next line from the client or server and return a pointer
 232    in *LINE to a buffer holding the line.  LINELEN is the length of
 233    *LINE.  The buffer is valid until the next read operation on it.
 234    The caller may modify the buffer.  The buffer is invalid (i.e. must
 235    not be used) if an error is returned.
 236
 237    Returns 0 on success or an assuan error code.
 238    See also: assuan_pending_line().
 239 */
 240 assuan_error_t
 241 assuan_read_line (assuan_context_t ctx, char **line, size_t *linelen)
 242 {
 243   assuan_error_t err;
 244
 245   if (!ctx)
 246     return _assuan_error (ASSUAN_Invalid_Value);
 247
 248   do
 249     {
 250       err = _assuan_read_line (ctx);
 251     }
 252   while (!ctx->in_inquire && _assuan_error_is_eagain (err));
 253
 254   *line = ctx->inbound.line;
 255   *linelen = ctx->inbound.linelen;
 256   return err;
 257 }
 258
 259
 260 /* Return true if a full line is buffered (i.e. an entire line may be
 261    read without any I/O).  */
 262 int
 263 assuan_pending_line (assuan_context_t ctx)
 264 {
 265   return ctx && ctx->inbound.attic.pending;
 266 }
 267
 268
 269 assuan_error_t
 270 _assuan_write_line (assuan_context_t ctx, const char *prefix,
 271                     const char *line, size_t len)
 272 {
 273   assuan_error_t rc = 0;
 274   size_t prefixlen = prefix? strlen (prefix):0;
 275   unsigned int monitor_result;
 276
 277   /* Make sure that the line is short enough. */
 278   if (len + prefixlen + 2 > ASSUAN_LINELENGTH)
 279     {
 280       if (ctx->log_fp)
 281         fprintf (ctx->log_fp, "%s[%u.%d] DBG: -> "
 282                  "[supplied line too long -truncated]\n",
 283                  assuan_get_assuan_log_prefix (),
 284                  (unsigned int)getpid (), (int)ctx->inbound.fd);
 285       if (prefixlen > 5)
 286         prefixlen = 5;
 287       if (len > ASSUAN_LINELENGTH - prefixlen - 2)
 288         len = ASSUAN_LINELENGTH - prefixlen - 2 - 1;
 289     }
 290
 291   monitor_result = (ctx->io_monitor
 292                     ? ctx->io_monitor (ctx, 1, line, len)
 293                     : 0);
 294
 295   /* Fixme: we should do some kind of line buffering.  */
 296   if (ctx->log_fp && !(monitor_result & 1))
 297     {
 298       fprintf (ctx->log_fp, "%s[%u.%d] DBG: -> ",
 299                assuan_get_assuan_log_prefix (),
 300                (unsigned int)getpid (), (int)ctx->inbound.fd);
 301       if (ctx->confidential)
 302         fputs ("[Confidential data not shown]", ctx->log_fp);
 303       else
 304         {
 305           if (prefixlen)
 306             _assuan_log_print_buffer (ctx->log_fp, prefix, prefixlen);
 307           _assuan_log_print_buffer (ctx->log_fp, line, len);
 308         }
 309       putc ('\n', ctx->log_fp);
 310     }
 311
 312   if (prefixlen && !(monitor_result & 2))
 313     {
 314       rc = writen (ctx, prefix, prefixlen);
 315       if (rc)
 316         rc = _assuan_error (ASSUAN_Write_Error);
 317     }
 318   if (!rc && !(monitor_result & 2))
 319     {
 320       rc = writen (ctx, line, len);
 321       if (rc)
 322         rc = _assuan_error (ASSUAN_Write_Error);
 323       if (!rc)
 324         {
 325           rc = writen (ctx, "\n", 1);
 326           if (rc)
 327             rc = _assuan_error (ASSUAN_Write_Error);
 328         }
 329     }
 330   return rc;
 331 }
 332
 333
 334 assuan_error_t
 335 assuan_write_line (assuan_context_t ctx, const char *line)
 336 {
 337   size_t len;
 338   const char *s;
 339
 340   if (!ctx)
 341     return _assuan_error (ASSUAN_Invalid_Value);
 342
 343   /* Make sure that we never take a LF from the user - this might
 344      violate the protocol. */
 345   s = strchr (line, '\n');
 346   len = s? (s-line) : strlen (line);
 347
 348   if (ctx->log_fp && s)
 349     fprintf (ctx->log_fp, "%s[%u.%d] DBG: -> "
 350              "[supplied line contained a LF - truncated]\n",
 351              assuan_get_assuan_log_prefix (),
 352              (unsigned int)getpid (), (int)ctx->inbound.fd);
 353
 354   return _assuan_write_line (ctx, NULL, line, len);
 355 }
 356
 357
 358 \f
 359 /* Write out the data in buffer as datalines with line wrapping and
 360    percent escaping.  This function is used for GNU's custom streams. */
 361 int
 362 _assuan_cookie_write_data (void *cookie, const char *buffer, size_t orig_size)
 363 {
 364   assuan_context_t ctx = cookie;
 365   size_t size = orig_size;
 366   char *line;
 367   size_t linelen;
 368
 369   if (ctx->outbound.data.error) {
 370       if (_assuan_error_is_eagain(ctx->outbound.data.error))
 371           ctx->outbound.data.error = 0;
 372       else
 373           return 0;
 374   }
 375
 376   line = ctx->outbound.data.line;
 377   linelen = ctx->outbound.data.linelen;
 378   line += linelen;
 379   while (size)
 380     {
 381       unsigned int monitor_result;
 382
 383       /* Insert data line header. */
 384       if (!linelen)
 385         {
 386           *line++ = 'D';
 387           *line++ = ' ';
 388           linelen += 2;
 389         }
 390
 391       /* Copy data, keep space for the CRLF and to escape one character. */
 392       while (size && linelen < LINELENGTH-2-2)
 393         {
 394           if (*buffer == '%' || *buffer == '\r' || *buffer == '\n')
 395             {
 396               sprintf (line, "%%%02X", *(unsigned char*)buffer);
 397               line += 3;
 398               linelen += 3;
 399               buffer++;
 400             }
 401           else
 402             {
 403               *line++ = *buffer++;
 404               linelen++;
 405             }
 406           size--;
 407         }
 408
 409
 410       monitor_result = (ctx->io_monitor
 411                         ? ctx->io_monitor (ctx, 1,
 412                                            ctx->outbound.data.line, linelen)
 413                         : 0);
 414
 415       if (linelen >= LINELENGTH-2-2)
 416         {
 417           if (ctx->log_fp && !(monitor_result & 1))
 418             {
 419               fprintf (ctx->log_fp, "%s[%u.%d] DBG: -> ",
 420                        assuan_get_assuan_log_prefix (),
 421                        (unsigned int)getpid (), (int)ctx->inbound.fd);
 422
 423               if (ctx->confidential)
 424                 fputs ("[Confidential data not shown]", ctx->log_fp);
 425               else
 426                 _assuan_log_print_buffer (ctx->log_fp,
 427                                           ctx->outbound.data.line,
 428                                           linelen);
 429               putc ('\n', ctx->log_fp);
 430             }
 431           *line++ = '\n';
 432           linelen++;
 433           if ( !(monitor_result & 2)
 434                && writen (ctx, ctx->outbound.data.line, linelen))
 435             {
 436               ctx->outbound.data.error = _assuan_error (ASSUAN_Write_Error);
 437               return 0;
 438             }
 439           line = ctx->outbound.data.line;
 440           linelen = 0;
 441         }
 442     }
 443
 444   ctx->outbound.data.linelen = linelen;
 445   return (int)orig_size;
 446 }
 447
 448
 449 /* Write out any buffered data
 450    This function is used for GNU's custom streams */
 451 int
 452 _assuan_cookie_write_flush (void *cookie)
 453 {
 454   assuan_context_t ctx = cookie;
 455   char *line;
 456   size_t linelen;
 457   unsigned int monitor_result;
 458
 459   if (ctx->outbound.data.error)
 460     return 0;
 461
 462   line = ctx->outbound.data.line;
 463   linelen = ctx->outbound.data.linelen;
 464   line += linelen;
 465
 466   monitor_result = (ctx->io_monitor
 467                     ? ctx->io_monitor (ctx, 1,
 468                                        ctx->outbound.data.line, linelen)
 469                     : 0);
 470
 471   if (linelen)
 472     {
 473       if (ctx->log_fp && !(monitor_result & 1))
 474         {
 475           fprintf (ctx->log_fp, "%s[%u.%d] DBG: -> ",
 476                    assuan_get_assuan_log_prefix (),
 477                    (unsigned int)getpid (), (int)ctx->inbound.fd);
 478           if (ctx->confidential)
 479             fputs ("[Confidential data not shown]", ctx->log_fp);
 480           else
 481             _assuan_log_print_buffer (ctx->log_fp,
 482                                       ctx->outbound.data.line, linelen);
 483           putc ('\n', ctx->log_fp);
 484         }
 485       *line++ = '\n';
 486       linelen++;
 487       if ( !(monitor_result & 2)
 488            && writen (ctx, ctx->outbound.data.line, linelen))
 489         {
 490           ctx->outbound.data.error = _assuan_error (ASSUAN_Write_Error);
 491           return 0;
 492         }
 493       ctx->outbound.data.linelen = 0;
 494     }
 495   return 0;
 496 }
 497
 498
 499 /**
 500  * assuan_send_data:
 501  * @ctx: An assuan context
 502  * @buffer: Data to send or NULL to flush
 503  * @length: length of the data to send/
 504  *
 505  * This function may be used by the server or the client to send data
 506  * lines.  The data will be escaped as required by the Assuan protocol
 507  * and may get buffered until a line is full.  To force sending the
 508  * data out @buffer may be passed as NULL (in which case @length must
 509  * also be 0); however when used by a client this flush operation does
 510  * also send the terminating "END" command to terminate the reponse on
 511  * a INQUIRE response.  However, when assuan_transact() is used, this
 512  * function takes care of sending END itself.
 513  *
 514  * Return value: 0 on success or an error code
 515  **/
 516 \f
 517 assuan_error_t
 518 assuan_send_data (assuan_context_t ctx, const void *buffer, size_t length)
 519 {
 520   if (!ctx)
 521     return _assuan_error (ASSUAN_Invalid_Value);
 522   if (!buffer && length)
 523     return _assuan_error (ASSUAN_Invalid_Value);
 524
 525   if (!buffer)
 526     { /* flush what we have */
 527       _assuan_cookie_write_flush (ctx);
 528       if (ctx->outbound.data.error)
 529         return ctx->outbound.data.error;
 530       if (!ctx->is_server)
 531         return assuan_write_line (ctx, "END");
 532     }
 533   else
 534     {
 535       _assuan_cookie_write_data (ctx, buffer, length);
 536       if (ctx->outbound.data.error)
 537         return ctx->outbound.data.error;
 538     }
 539
 540   return 0;
 541 }
 542
 543 assuan_error_t
 544 assuan_sendfd (assuan_context_t ctx, assuan_fd_t fd)
 545 {
 546   /* It is explicitly allowed to use (NULL, -1) as a runtime test to
 547      check whether descriptor passing is available. */
 548   if (!ctx && fd == ASSUAN_INVALID_FD)
 549 #ifdef USE_DESCRIPTOR_PASSING
 550     return 0;
 551 #else
 552     return _assuan_error (ASSUAN_Not_Implemented);
 553 #endif
 554
 555   if (! ctx->io->sendfd)
 556     return set_error (ctx, Not_Implemented,
 557                       "server does not support sending and receiving "
 558                       "of file descriptors");
 559   return ctx->io->sendfd (ctx, fd);
 560 }
 561
 562 assuan_error_t
 563 assuan_receivefd (assuan_context_t ctx, assuan_fd_t *fd)
 564 {
 565   if (! ctx->io->receivefd)
 566     return set_error (ctx, Not_Implemented,
 567                       "server does not support sending and receiving "
 568                       "of file descriptors");
 569   return ctx->io->receivefd (ctx, fd);
 570 }