glib/giounix.c

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * giounix.c: IO Channels using unix file descriptors
   5  * Copyright 1998 Owen Taylor
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the
  19  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20  * Boston, MA 02111-1307, USA.
  21  */
  22
  23 /*
  24  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  25  * file for a list of people on the GLib Team.  See the ChangeLog
  26  * files for a list of changes.  These files are distributed with
  27  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  28  */
  29
  30 /*
  31  * MT safe
  32  */
  33
  34 #include "config.h"
  35
  36 #define _POSIX_SOURCE           /* for SSIZE_MAX */
  37
  38 #include <sys/types.h>
  39 #include <sys/stat.h>
  40 #include <stdio.h>
  41 #include <unistd.h>
  42 #include <errno.h>
  43 #include <string.h>
  44 #include <fcntl.h>
  45
  46 #include "giochannel.h"
  47
  48 #include "gerror.h"
  49 #include "gfileutils.h"
  50 #include "gstrfuncs.h"
  51 #include "gtestutils.h"
  52
  53 /*
  54  * Unix IO Channels
  55  */
  56
  57 typedef struct _GIOUnixChannel GIOUnixChannel;
  58 typedef struct _GIOUnixWatch GIOUnixWatch;
  59
  60 struct _GIOUnixChannel
  61 {
  62   GIOChannel channel;
  63   gint fd;
  64 };
  65
  66 struct _GIOUnixWatch
  67 {
  68   GSource       source;
  69   GPollFD       pollfd;
  70   GIOChannel   *channel;
  71   GIOCondition  condition;
  72 };
  73
  74
  75 static GIOStatus        g_io_unix_read          (GIOChannel   *channel,
  76                                                  gchar        *buf,
  77                                                  gsize         count,
  78                                                  gsize        *bytes_read,
  79                                                  GError      **err);
  80 static GIOStatus        g_io_unix_write         (GIOChannel   *channel,
  81                                                  const gchar  *buf,
  82                                                  gsize         count,
  83                                                  gsize        *bytes_written,
  84                                                  GError      **err);
  85 static GIOStatus        g_io_unix_seek          (GIOChannel   *channel,
  86                                                  gint64        offset,
  87                                                  GSeekType     type,
  88                                                  GError      **err);
  89 static GIOStatus        g_io_unix_close         (GIOChannel   *channel,
  90                                                  GError      **err);
  91 static void             g_io_unix_free          (GIOChannel   *channel);
  92 static GSource*         g_io_unix_create_watch  (GIOChannel   *channel,
  93                                                  GIOCondition  condition);
  94 static GIOStatus        g_io_unix_set_flags     (GIOChannel   *channel,
  95                                                  GIOFlags      flags,
  96                                                  GError      **err);
  97 static GIOFlags         g_io_unix_get_flags     (GIOChannel   *channel);
  98
  99 static gboolean g_io_unix_prepare  (GSource     *source,
 100                                     gint        *timeout);
 101 static gboolean g_io_unix_check    (GSource     *source);
 102 static gboolean g_io_unix_dispatch (GSource     *source,
 103                                     GSourceFunc  callback,
 104                                     gpointer     user_data);
 105 static void     g_io_unix_finalize (GSource     *source);
 106
 107 GSourceFuncs g_io_watch_funcs = {
 108   g_io_unix_prepare,
 109   g_io_unix_check,
 110   g_io_unix_dispatch,
 111   g_io_unix_finalize
 112 };
 113
 114 static GIOFuncs unix_channel_funcs = {
 115   g_io_unix_read,
 116   g_io_unix_write,
 117   g_io_unix_seek,
 118   g_io_unix_close,
 119   g_io_unix_create_watch,
 120   g_io_unix_free,
 121   g_io_unix_set_flags,
 122   g_io_unix_get_flags,
 123 };
 124
 125 static gboolean
 126 g_io_unix_prepare (GSource  *source,
 127                    gint     *timeout)
 128 {
 129   GIOUnixWatch *watch = (GIOUnixWatch *)source;
 130   GIOCondition buffer_condition = g_io_channel_get_buffer_condition (watch->channel);
 131
 132   *timeout = -1;
 133
 134   /* Only return TRUE here if _all_ bits in watch->condition will be set
 135    */
 136   return ((watch->condition & buffer_condition) == watch->condition);
 137 }
 138
 139 static gboolean
 140 g_io_unix_check (GSource  *source)
 141 {
 142   GIOUnixWatch *watch = (GIOUnixWatch *)source;
 143   GIOCondition buffer_condition = g_io_channel_get_buffer_condition (watch->channel);
 144   GIOCondition poll_condition = watch->pollfd.revents;
 145
 146   return ((poll_condition | buffer_condition) & watch->condition);
 147 }
 148
 149 static gboolean
 150 g_io_unix_dispatch (GSource     *source,
 151                     GSourceFunc  callback,
 152                     gpointer     user_data)
 153
 154 {
 155   GIOFunc func = (GIOFunc)callback;
 156   GIOUnixWatch *watch = (GIOUnixWatch *)source;
 157   GIOCondition buffer_condition = g_io_channel_get_buffer_condition (watch->channel);
 158
 159   if (!func)
 160     {
 161       g_warning ("IO watch dispatched without callback\n"
 162                  "You must call g_source_connect().");
 163       return FALSE;
 164     }
 165
 166   return (*func) (watch->channel,
 167                   (watch->pollfd.revents | buffer_condition) & watch->condition,
 168                   user_data);
 169 }
 170
 171 static void
 172 g_io_unix_finalize (GSource *source)
 173 {
 174   GIOUnixWatch *watch = (GIOUnixWatch *)source;
 175
 176   g_io_channel_unref (watch->channel);
 177 }
 178
 179 static GIOStatus
 180 g_io_unix_read (GIOChannel *channel,
 181                 gchar      *buf,
 182                 gsize       count,
 183                 gsize      *bytes_read,
 184                 GError    **err)
 185 {
 186   GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;
 187   gssize result;
 188
 189   if (count > SSIZE_MAX) /* At least according to the Debian manpage for read */
 190     count = SSIZE_MAX;
 191
 192  retry:
 193   result = read (unix_channel->fd, buf, count);
 194
 195   if (result < 0)
 196     {
 197       int errsv = errno;
 198       *bytes_read = 0;
 199
 200       switch (errsv)
 201         {
 202 #ifdef EINTR
 203           case EINTR:
 204             goto retry;
 205 #endif
 206 #ifdef EAGAIN
 207           case EAGAIN:
 208             return G_IO_STATUS_AGAIN;
 209 #endif
 210           default:
 211             g_set_error_literal (err, G_IO_CHANNEL_ERROR,
 212                                  g_io_channel_error_from_errno (errsv),
 213                                  g_strerror (errsv));
 214             return G_IO_STATUS_ERROR;
 215         }
 216     }
 217
 218   *bytes_read = result;
 219
 220   return (result > 0) ? G_IO_STATUS_NORMAL : G_IO_STATUS_EOF;
 221 }
 222
 223 static GIOStatus
 224 g_io_unix_write (GIOChannel  *channel,
 225                  const gchar *buf,
 226                  gsize       count,
 227                  gsize      *bytes_written,
 228                  GError    **err)
 229 {
 230   GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;
 231   gssize result;
 232
 233  retry:
 234   result = write (unix_channel->fd, buf, count);
 235
 236   if (result < 0)
 237     {
 238       int errsv = errno;
 239       *bytes_written = 0;
 240
 241       switch (errsv)
 242         {
 243 #ifdef EINTR
 244           case EINTR:
 245             goto retry;
 246 #endif
 247 #ifdef EAGAIN
 248           case EAGAIN:
 249             return G_IO_STATUS_AGAIN;
 250 #endif
 251           default:
 252             g_set_error_literal (err, G_IO_CHANNEL_ERROR,
 253                                  g_io_channel_error_from_errno (errsv),
 254                                  g_strerror (errsv));
 255             return G_IO_STATUS_ERROR;
 256         }
 257     }
 258
 259   *bytes_written = result;
 260
 261   return G_IO_STATUS_NORMAL;
 262 }
 263
 264 static GIOStatus
 265 g_io_unix_seek (GIOChannel *channel,
 266                 gint64      offset,
 267                 GSeekType   type,
 268                 GError    **err)
 269 {
 270   GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;
 271   int whence;
 272   off_t tmp_offset;
 273   off_t result;
 274
 275   switch (type)
 276     {
 277     case G_SEEK_SET:
 278       whence = SEEK_SET;
 279       break;
 280     case G_SEEK_CUR:
 281       whence = SEEK_CUR;
 282       break;
 283     case G_SEEK_END:
 284       whence = SEEK_END;
 285       break;
 286     default:
 287       whence = -1; /* Shut the compiler up */
 288       g_assert_not_reached ();
 289     }
 290
 291   tmp_offset = offset;
 292   if (tmp_offset != offset)
 293     {
 294       g_set_error_literal (err, G_IO_CHANNEL_ERROR,
 295                            g_io_channel_error_from_errno (EINVAL),
 296                            g_strerror (EINVAL));
 297       return G_IO_STATUS_ERROR;
 298     }
 299
 300   result = lseek (unix_channel->fd, tmp_offset, whence);
 301
 302   if (result < 0)
 303     {
 304       int errsv = errno;
 305       g_set_error_literal (err, G_IO_CHANNEL_ERROR,
 306                            g_io_channel_error_from_errno (errsv),
 307                            g_strerror (errsv));
 308       return G_IO_STATUS_ERROR;
 309     }
 310
 311   return G_IO_STATUS_NORMAL;
 312 }
 313
 314
 315 static GIOStatus
 316 g_io_unix_close (GIOChannel *channel,
 317                  GError    **err)
 318 {
 319   GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;
 320
 321   if (close (unix_channel->fd) < 0)
 322     {
 323       int errsv = errno;
 324       g_set_error_literal (err, G_IO_CHANNEL_ERROR,
 325                            g_io_channel_error_from_errno (errsv),
 326                            g_strerror (errsv));
 327       return G_IO_STATUS_ERROR;
 328     }
 329
 330   return G_IO_STATUS_NORMAL;
 331 }
 332
 333 static void
 334 g_io_unix_free (GIOChannel *channel)
 335 {
 336   GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;
 337
 338   g_free (unix_channel);
 339 }
 340
 341 static GSource *
 342 g_io_unix_create_watch (GIOChannel   *channel,
 343                         GIOCondition  condition)
 344 {
 345   GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;
 346   GSource *source;
 347   GIOUnixWatch *watch;
 348
 349
 350   source = g_source_new (&g_io_watch_funcs, sizeof (GIOUnixWatch));
 351   g_source_set_name (source, "GIOChannel (Unix)");
 352   watch = (GIOUnixWatch *)source;
 353
 354   watch->channel = channel;
 355   g_io_channel_ref (channel);
 356
 357   watch->condition = condition;
 358
 359   watch->pollfd.fd = unix_channel->fd;
 360   watch->pollfd.events = condition;
 361
 362   g_source_add_poll (source, &watch->pollfd);
 363
 364   return source;
 365 }
 366
 367 static GIOStatus
 368 g_io_unix_set_flags (GIOChannel *channel,
 369                      GIOFlags    flags,
 370                      GError    **err)
 371 {
 372   glong fcntl_flags;
 373   GIOUnixChannel *unix_channel = (GIOUnixChannel *) channel;
 374
 375   fcntl_flags = 0;
 376
 377   if (flags & G_IO_FLAG_APPEND)
 378     fcntl_flags |= O_APPEND;
 379   if (flags & G_IO_FLAG_NONBLOCK)
 380 #ifdef O_NONBLOCK
 381     fcntl_flags |= O_NONBLOCK;
 382 #else
 383     fcntl_flags |= O_NDELAY;
 384 #endif
 385
 386   if (fcntl (unix_channel->fd, F_SETFL, fcntl_flags) == -1)
 387     {
 388       int errsv = errno;
 389       g_set_error_literal (err, G_IO_CHANNEL_ERROR,
 390                            g_io_channel_error_from_errno (errsv),
 391                            g_strerror (errsv));
 392       return G_IO_STATUS_ERROR;
 393     }
 394
 395   return G_IO_STATUS_NORMAL;
 396 }
 397
 398 static GIOFlags
 399 g_io_unix_get_flags (GIOChannel *channel)
 400 {
 401   GIOFlags flags = 0;
 402   glong fcntl_flags;
 403   GIOUnixChannel *unix_channel = (GIOUnixChannel *) channel;
 404
 405   fcntl_flags = fcntl (unix_channel->fd, F_GETFL);
 406
 407   if (fcntl_flags == -1)
 408     {
 409       int err = errno;
 410       g_warning (G_STRLOC "Error while getting flags for FD: %s (%d)\n",
 411                  g_strerror (err), err);
 412       return 0;
 413     }
 414
 415   if (fcntl_flags & O_APPEND)
 416     flags |= G_IO_FLAG_APPEND;
 417 #ifdef O_NONBLOCK
 418   if (fcntl_flags & O_NONBLOCK)
 419 #else
 420   if (fcntl_flags & O_NDELAY)
 421 #endif
 422     flags |= G_IO_FLAG_NONBLOCK;
 423
 424   switch (fcntl_flags & (O_RDONLY | O_WRONLY | O_RDWR))
 425     {
 426       case O_RDONLY:
 427         channel->is_readable = TRUE;
 428         channel->is_writeable = FALSE;
 429         break;
 430       case O_WRONLY:
 431         channel->is_readable = FALSE;
 432         channel->is_writeable = TRUE;
 433         break;
 434       case O_RDWR:
 435         channel->is_readable = TRUE;
 436         channel->is_writeable = TRUE;
 437         break;
 438       default:
 439         g_assert_not_reached ();
 440     }
 441
 442   return flags;
 443 }
 444
 445 GIOChannel *
 446 g_io_channel_new_file (const gchar *filename,
 447                        const gchar *mode,
 448                        GError     **error)
 449 {
 450   int fid, flags;
 451   mode_t create_mode;
 452   GIOChannel *channel;
 453   enum { /* Cheesy hack */
 454     MODE_R = 1 << 0,
 455     MODE_W = 1 << 1,
 456     MODE_A = 1 << 2,
 457     MODE_PLUS = 1 << 3,
 458     MODE_R_PLUS = MODE_R | MODE_PLUS,
 459     MODE_W_PLUS = MODE_W | MODE_PLUS,
 460     MODE_A_PLUS = MODE_A | MODE_PLUS
 461   } mode_num;
 462   struct stat buffer;
 463
 464   g_return_val_if_fail (filename != NULL, NULL);
 465   g_return_val_if_fail (mode != NULL, NULL);
 466   g_return_val_if_fail ((error == NULL) || (*error == NULL), NULL);
 467
 468   switch (mode[0])
 469     {
 470       case 'r':
 471         mode_num = MODE_R;
 472         break;
 473       case 'w':
 474         mode_num = MODE_W;
 475         break;
 476       case 'a':
 477         mode_num = MODE_A;
 478         break;
 479       default:
 480         g_warning ("Invalid GIOFileMode %s.\n", mode);
 481         return NULL;
 482     }
 483
 484   switch (mode[1])
 485     {
 486       case '\0':
 487         break;
 488       case '+':
 489         if (mode[2] == '\0')
 490           {
 491             mode_num |= MODE_PLUS;
 492             break;
 493           }
 494         /* Fall through */
 495       default:
 496         g_warning ("Invalid GIOFileMode %s.\n", mode);
 497         return NULL;
 498     }
 499
 500   switch (mode_num)
 501     {
 502       case MODE_R:
 503         flags = O_RDONLY;
 504         break;
 505       case MODE_W:
 506         flags = O_WRONLY | O_TRUNC | O_CREAT;
 507         break;
 508       case MODE_A:
 509         flags = O_WRONLY | O_APPEND | O_CREAT;
 510         break;
 511       case MODE_R_PLUS:
 512         flags = O_RDWR;
 513         break;
 514       case MODE_W_PLUS:
 515         flags = O_RDWR | O_TRUNC | O_CREAT;
 516         break;
 517       case MODE_A_PLUS:
 518         flags = O_RDWR | O_APPEND | O_CREAT;
 519         break;
 520       case MODE_PLUS:
 521       default:
 522         g_assert_not_reached ();
 523         flags = 0;
 524     }
 525
 526   create_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
 527
 528   do
 529     {
 530       fid = open (filename, flags, create_mode);
 531     }
 532   while (fid == -1 && errno == EINTR);
 533
 534   if (fid == -1)
 535     {
 536       int err = errno;
 537       g_set_error_literal (error, G_FILE_ERROR,
 538                            g_file_error_from_errno (err),
 539                            g_strerror (err));
 540       return (GIOChannel *)NULL;
 541     }
 542
 543   if (fstat (fid, &buffer) == -1) /* In case someone opens a FIFO */
 544     {
 545       int err = errno;
 546       close (fid);
 547       g_set_error_literal (error, G_FILE_ERROR,
 548                            g_file_error_from_errno (err),
 549                            g_strerror (err));
 550       return (GIOChannel *)NULL;
 551     }
 552
 553   channel = (GIOChannel *) g_new (GIOUnixChannel, 1);
 554
 555   channel->is_seekable = S_ISREG (buffer.st_mode) || S_ISCHR (buffer.st_mode)
 556                          || S_ISBLK (buffer.st_mode);
 557
 558   switch (mode_num)
 559     {
 560       case MODE_R:
 561         channel->is_readable = TRUE;
 562         channel->is_writeable = FALSE;
 563         break;
 564       case MODE_W:
 565       case MODE_A:
 566         channel->is_readable = FALSE;
 567         channel->is_writeable = TRUE;
 568         break;
 569       case MODE_R_PLUS:
 570       case MODE_W_PLUS:
 571       case MODE_A_PLUS:
 572         channel->is_readable = TRUE;
 573         channel->is_writeable = TRUE;
 574         break;
 575       case MODE_PLUS:
 576       default:
 577         g_assert_not_reached ();
 578     }
 579
 580   g_io_channel_init (channel);
 581   channel->close_on_unref = TRUE; /* must be after g_io_channel_init () */
 582   channel->funcs = &unix_channel_funcs;
 583
 584   ((GIOUnixChannel *) channel)->fd = fid;
 585   return channel;
 586 }
 587
 588 /**
 589  * g_io_channel_unix_new:
 590  * @fd: a file descriptor.
 591  * @Returns: a new #GIOChannel.
 592  *
 593  * Creates a new #GIOChannel given a file descriptor. On UNIX systems
 594  * this works for plain files, pipes, and sockets.
 595  *
 596  * The returned #GIOChannel has a reference count of 1.
 597  *
 598  * The default encoding for #GIOChannel is UTF-8. If your application
 599  * is reading output from a command using via pipe, you may need to set
 600  * the encoding to the encoding of the current locale (see
 601  * g_get_charset()) with the g_io_channel_set_encoding() function.
 602  *
 603  * If you want to read raw binary data without interpretation, then
 604  * call the g_io_channel_set_encoding() function with %NULL for the
 605  * encoding argument.
 606  *
 607  * This function is available in GLib on Windows, too, but you should
 608  * avoid using it on Windows. The domain of file descriptors and
 609  * sockets overlap. There is no way for GLib to know which one you mean
 610  * in case the argument you pass to this function happens to be both a
 611  * valid file descriptor and socket. If that happens a warning is
 612  * issued, and GLib assumes that it is the file descriptor you mean.
 613  **/
 614 GIOChannel *
 615 g_io_channel_unix_new (gint fd)
 616 {
 617   struct stat buffer;
 618   GIOUnixChannel *unix_channel = g_new (GIOUnixChannel, 1);
 619   GIOChannel *channel = (GIOChannel *)unix_channel;
 620
 621   g_io_channel_init (channel);
 622   channel->funcs = &unix_channel_funcs;
 623
 624   unix_channel->fd = fd;
 625
 626   /* I'm not sure if fstat on a non-file (e.g., socket) works
 627    * it should be safe to say if it fails, the fd isn't seekable.
 628    */
 629   /* Newer UNIX versions support S_ISSOCK(), fstat() will probably
 630    * succeed in most cases.
 631    */
 632   if (fstat (unix_channel->fd, &buffer) == 0)
 633     channel->is_seekable = S_ISREG (buffer.st_mode) || S_ISCHR (buffer.st_mode)
 634                            || S_ISBLK (buffer.st_mode);
 635   else /* Assume not seekable */
 636     channel->is_seekable = FALSE;
 637
 638   g_io_unix_get_flags (channel); /* Sets is_readable, is_writeable */
 639
 640   return channel;
 641 }
 642
 643 /**
 644  * g_io_channel_unix_get_fd:
 645  * @channel: a #GIOChannel, created with g_io_channel_unix_new().
 646  * @Returns: the file descriptor of the #GIOChannel.
 647  *
 648  * Returns the file descriptor of the #GIOChannel.
 649  *
 650  * On Windows this function returns the file descriptor or socket of
 651  * the #GIOChannel.
 652  **/
 653 gint
 654 g_io_channel_unix_get_fd (GIOChannel *channel)
 655 {
 656   GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;
 657   return unix_channel->fd;
 658 }