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