1 /* GIO - GLib Input, Output and Streaming Library
3 * Copyright (C) 2006-2007 Red Hat, Inc.
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General
16 * Public License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
18 * Boston, MA 02111-1307, USA.
20 * Author: Alexander Larsson <alexl@redhat.com>
25 #include <sys/types.h>
35 #include <glib/gstdio.h>
38 #include "glocalfileoutputstream.h"
39 #include "glocalfileinfo.h"
44 #define S_ISDIR(m) (((m) & _S_IFMT) == _S_IFDIR)
47 #define S_ISREG(m) (((m) & _S_IFMT) == _S_IFREG)
53 #define g_local_file_output_stream_get_type _g_local_file_output_stream_get_type
54 G_DEFINE_TYPE (GLocalFileOutputStream, g_local_file_output_stream, G_TYPE_FILE_OUTPUT_STREAM);
56 /* Some of the file replacement code was based on the code from gedit,
57 * relicenced to LGPL with permissions from the authors.
60 #define BACKUP_EXTENSION "~"
62 struct _GLocalFileOutputStreamPrivate {
64 char *original_filename;
65 char *backup_filename;
70 static gssize g_local_file_output_stream_write (GOutputStream *stream,
73 GCancellable *cancellable,
75 static gboolean g_local_file_output_stream_close (GOutputStream *stream,
76 GCancellable *cancellable,
78 static GFileInfo *g_local_file_output_stream_query_info (GFileOutputStream *stream,
80 GCancellable *cancellable,
82 static char * g_local_file_output_stream_get_etag (GFileOutputStream *stream);
83 static goffset g_local_file_output_stream_tell (GFileOutputStream *stream);
84 static gboolean g_local_file_output_stream_can_seek (GFileOutputStream *stream);
85 static gboolean g_local_file_output_stream_seek (GFileOutputStream *stream,
88 GCancellable *cancellable,
90 static gboolean g_local_file_output_stream_can_truncate (GFileOutputStream *stream);
91 static gboolean g_local_file_output_stream_truncate (GFileOutputStream *stream,
93 GCancellable *cancellable,
97 g_local_file_output_stream_finalize (GObject *object)
99 GLocalFileOutputStream *file;
101 file = G_LOCAL_FILE_OUTPUT_STREAM (object);
103 g_free (file->priv->tmp_filename);
104 g_free (file->priv->original_filename);
105 g_free (file->priv->backup_filename);
106 g_free (file->priv->etag);
108 if (G_OBJECT_CLASS (g_local_file_output_stream_parent_class)->finalize)
109 (*G_OBJECT_CLASS (g_local_file_output_stream_parent_class)->finalize) (object);
113 g_local_file_output_stream_class_init (GLocalFileOutputStreamClass *klass)
115 GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
116 GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass);
117 GFileOutputStreamClass *file_stream_class = G_FILE_OUTPUT_STREAM_CLASS (klass);
119 g_type_class_add_private (klass, sizeof (GLocalFileOutputStreamPrivate));
121 gobject_class->finalize = g_local_file_output_stream_finalize;
123 stream_class->write_fn = g_local_file_output_stream_write;
124 stream_class->close_fn = g_local_file_output_stream_close;
125 file_stream_class->query_info = g_local_file_output_stream_query_info;
126 file_stream_class->get_etag = g_local_file_output_stream_get_etag;
127 file_stream_class->tell = g_local_file_output_stream_tell;
128 file_stream_class->can_seek = g_local_file_output_stream_can_seek;
129 file_stream_class->seek = g_local_file_output_stream_seek;
130 file_stream_class->can_truncate = g_local_file_output_stream_can_truncate;
131 file_stream_class->truncate_fn = g_local_file_output_stream_truncate;
135 g_local_file_output_stream_init (GLocalFileOutputStream *stream)
137 stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream,
138 G_TYPE_LOCAL_FILE_OUTPUT_STREAM,
139 GLocalFileOutputStreamPrivate);
143 g_local_file_output_stream_write (GOutputStream *stream,
146 GCancellable *cancellable,
149 GLocalFileOutputStream *file;
152 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
156 if (g_cancellable_set_error_if_cancelled (cancellable, error))
158 res = write (file->priv->fd, buffer, count);
166 g_set_error (error, G_IO_ERROR,
167 g_io_error_from_errno (errsv),
168 _("Error writing to file: %s"),
179 g_local_file_output_stream_close (GOutputStream *stream,
180 GCancellable *cancellable,
183 GLocalFileOutputStream *file;
184 struct stat final_stat;
187 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
189 if (file->priv->tmp_filename)
191 /* We need to move the temp file to its final place,
192 * and possibly create the backup file
195 if (file->priv->backup_filename)
197 if (g_cancellable_set_error_if_cancelled (cancellable, error))
201 /* create original -> backup link, the original is then renamed over */
202 if (unlink (file->priv->backup_filename) != 0 &&
207 g_set_error (error, G_IO_ERROR,
208 G_IO_ERROR_CANT_CREATE_BACKUP,
209 _("Error removing old backup link: %s"),
214 if (link (file->priv->original_filename, file->priv->backup_filename) != 0)
216 /* link failed or is not supported, try rename */
217 if (rename (file->priv->original_filename, file->priv->backup_filename) != 0)
221 g_set_error (error, G_IO_ERROR,
222 G_IO_ERROR_CANT_CREATE_BACKUP,
223 _("Error creating backup copy: %s"),
229 /* If link not supported, just rename... */
230 if (rename (file->priv->original_filename, file->priv->backup_filename) != 0)
234 g_set_error (error, G_IO_ERROR,
235 G_IO_ERROR_CANT_CREATE_BACKUP,
236 _("Error creating backup copy: %s"),
244 if (g_cancellable_set_error_if_cancelled (cancellable, error))
247 /* tmp -> original */
248 if (rename (file->priv->tmp_filename, file->priv->original_filename) != 0)
252 g_set_error (error, G_IO_ERROR,
253 g_io_error_from_errno (errno),
254 _("Error renaming temporary file: %s"),
260 if (g_cancellable_set_error_if_cancelled (cancellable, error))
263 if (fstat (file->priv->fd, &final_stat) == 0)
264 file->priv->etag = _g_local_file_info_create_etag (&final_stat);
268 res = close (file->priv->fd);
273 g_set_error (error, G_IO_ERROR,
274 g_io_error_from_errno (errsv),
275 _("Error closing file: %s"),
284 /* A simple try to close the fd in case we fail before the actual close */
285 close (file->priv->fd);
290 g_local_file_output_stream_get_etag (GFileOutputStream *stream)
292 GLocalFileOutputStream *file;
294 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
296 return g_strdup (file->priv->etag);
300 g_local_file_output_stream_tell (GFileOutputStream *stream)
302 GLocalFileOutputStream *file;
305 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
307 pos = lseek (file->priv->fd, 0, SEEK_CUR);
309 if (pos == (off_t)-1)
316 g_local_file_output_stream_can_seek (GFileOutputStream *stream)
318 GLocalFileOutputStream *file;
321 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
323 pos = lseek (file->priv->fd, 0, SEEK_CUR);
325 if (pos == (off_t)-1 && errno == ESPIPE)
332 seek_type_to_lseek (GSeekType type)
349 g_local_file_output_stream_seek (GFileOutputStream *stream,
352 GCancellable *cancellable,
355 GLocalFileOutputStream *file;
358 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
360 pos = lseek (file->priv->fd, offset, seek_type_to_lseek (type));
362 if (pos == (off_t)-1)
366 g_set_error (error, G_IO_ERROR,
367 g_io_error_from_errno (errsv),
368 _("Error seeking in file: %s"),
377 g_local_file_output_stream_can_truncate (GFileOutputStream *stream)
379 /* We can't truncate pipes and stuff where we can't seek */
380 return g_local_file_output_stream_can_seek (stream);
384 g_local_file_output_stream_truncate (GFileOutputStream *stream,
386 GCancellable *cancellable,
389 GLocalFileOutputStream *file;
392 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
396 res = g_win32_ftruncate (file->priv->fd, size);
398 res = ftruncate (file->priv->fd, size);
407 if (g_cancellable_set_error_if_cancelled (cancellable, error))
412 g_set_error (error, G_IO_ERROR,
413 g_io_error_from_errno (errsv),
414 _("Error truncating file: %s"),
424 g_local_file_output_stream_query_info (GFileOutputStream *stream,
426 GCancellable *cancellable,
429 GLocalFileOutputStream *file;
431 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
433 if (g_cancellable_set_error_if_cancelled (cancellable, error))
436 return _g_local_file_info_get_from_fd (file->priv->fd,
442 _g_local_file_output_stream_create (const char *filename,
443 GFileCreateFlags flags,
444 GCancellable *cancellable,
447 GLocalFileOutputStream *stream;
451 if (g_cancellable_set_error_if_cancelled (cancellable, error))
454 if (flags & G_FILE_CREATE_PRIVATE)
459 fd = g_open (filename, O_CREAT | O_EXCL | O_WRONLY, mode);
465 /* This must be an invalid filename, on e.g. FAT */
466 g_set_error (error, G_IO_ERROR,
467 G_IO_ERROR_INVALID_FILENAME,
468 _("Invalid filename"));
470 g_set_error (error, G_IO_ERROR,
471 g_io_error_from_errno (errsv),
472 _("Error opening file '%s': %s"),
473 filename, g_strerror (errsv));
477 stream = g_object_new (G_TYPE_LOCAL_FILE_OUTPUT_STREAM, NULL);
478 stream->priv->fd = fd;
479 return G_FILE_OUTPUT_STREAM (stream);
483 _g_local_file_output_stream_append (const char *filename,
484 GFileCreateFlags flags,
485 GCancellable *cancellable,
488 GLocalFileOutputStream *stream;
492 if (g_cancellable_set_error_if_cancelled (cancellable, error))
495 if (flags & G_FILE_CREATE_PRIVATE)
500 fd = g_open (filename, O_CREAT | O_APPEND | O_WRONLY, mode);
506 /* This must be an invalid filename, on e.g. FAT */
507 g_set_error (error, G_IO_ERROR,
508 G_IO_ERROR_INVALID_FILENAME,
509 _("Invalid filename"));
511 g_set_error (error, G_IO_ERROR,
512 g_io_error_from_errno (errsv),
513 _("Error opening file '%s': %s"),
514 filename, g_strerror (errsv));
518 stream = g_object_new (G_TYPE_LOCAL_FILE_OUTPUT_STREAM, NULL);
519 stream->priv->fd = fd;
521 return G_FILE_OUTPUT_STREAM (stream);
525 create_backup_filename (const char *filename)
527 return g_strconcat (filename, BACKUP_EXTENSION, NULL);
530 #define BUFSIZE 8192 /* size of normal write buffer */
533 copy_file_data (gint sfd,
539 const gchar *write_buffer;
541 gssize bytes_to_write;
542 gssize bytes_written;
544 buffer = g_malloc (BUFSIZE);
548 bytes_read = read (sfd, buffer, BUFSIZE);
549 if (bytes_read == -1)
556 g_set_error (error, G_IO_ERROR,
557 g_io_error_from_errno (errsv),
558 _("Error reading from file: %s"),
564 bytes_to_write = bytes_read;
565 write_buffer = buffer;
569 bytes_written = write (dfd, write_buffer, bytes_to_write);
570 if (bytes_written == -1)
577 g_set_error (error, G_IO_ERROR,
578 g_io_error_from_errno (errsv),
579 _("Error writing to file: %s"),
585 bytes_to_write -= bytes_written;
586 write_buffer += bytes_written;
588 while (bytes_to_write > 0);
590 } while ((bytes_read != 0) && (ret == TRUE));
598 handle_overwrite_open (const char *filename,
600 gboolean create_backup,
601 char **temp_filename,
602 GCancellable *cancellable,
606 struct stat original_stat;
611 /* We only need read access to the original file if we are creating a backup.
612 * We also add O_CREATE to avoid a race if the file was just removed */
614 open_flags = O_RDWR | O_CREAT;
616 open_flags = O_WRONLY | O_CREAT;
618 /* Some systems have O_NOFOLLOW, which lets us avoid some races
619 * when finding out if the file we opened was a symlink */
622 fd = g_open (filename, open_flags | O_NOFOLLOW, 0666);
623 if (fd == -1 && errno == ELOOP)
625 /* Could be a symlink, or it could be a regular ELOOP error,
626 * but then the next open will fail too. */
628 fd = g_open (filename, open_flags, 0666);
631 fd = g_open (filename, open_flags, 0666);
632 /* This is racy, but we do it as soon as possible to minimize the race */
633 is_symlink = g_file_test (filename, G_FILE_TEST_IS_SYMLINK);
640 g_set_error (error, G_IO_ERROR,
641 g_io_error_from_errno (errsv),
642 _("Error opening file '%s': %s"),
643 filename, g_strerror (errsv));
647 if (fstat (fd, &original_stat) != 0)
651 g_set_error (error, G_IO_ERROR,
652 g_io_error_from_errno (errsv),
653 _("Error stating file '%s': %s"),
654 filename, g_strerror (errsv));
658 /* not a regular file */
659 if (!S_ISREG (original_stat.st_mode))
661 if (S_ISDIR (original_stat.st_mode))
664 G_IO_ERROR_IS_DIRECTORY,
665 _("Target file is a directory"));
669 G_IO_ERROR_NOT_REGULAR_FILE,
670 _("Target file is not a regular file"));
676 current_etag = _g_local_file_info_create_etag (&original_stat);
677 if (strcmp (etag, current_etag) != 0)
681 G_IO_ERROR_WRONG_ETAG,
682 _("The file was externally modified"));
683 g_free (current_etag);
686 g_free (current_etag);
689 /* We use two backup strategies.
690 * The first one (which is faster) consist in saving to a
691 * tmp file then rename the original file to the backup and the
692 * tmp file to the original name. This is fast but doesn't work
693 * when the file is a link (hard or symbolic) or when we can't
694 * write to the current dir or can't set the permissions on the
696 * The second strategy consist simply in copying the old file
697 * to a backup file and rewrite the contents of the file.
700 if (!(original_stat.st_nlink > 1) && !is_symlink)
702 char *dirname, *tmp_filename;
705 dirname = g_path_get_dirname (filename);
706 tmp_filename = g_build_filename (dirname, ".goutputstream-XXXXXX", NULL);
709 tmpfd = g_mkstemp (tmp_filename);
712 g_free (tmp_filename);
713 goto fallback_strategy;
716 /* try to keep permissions */
720 fchown (tmpfd, original_stat.st_uid, original_stat.st_gid) == -1 ||
723 fchmod (tmpfd, original_stat.st_mode) == -1 ||
728 struct stat tmp_statbuf;
730 /* Check that we really needed to change something */
731 if (fstat (tmpfd, &tmp_statbuf) != 0 ||
732 original_stat.st_uid != tmp_statbuf.st_uid ||
733 original_stat.st_gid != tmp_statbuf.st_gid ||
734 original_stat.st_mode != tmp_statbuf.st_mode)
737 unlink (tmp_filename);
738 g_free (tmp_filename);
739 goto fallback_strategy;
744 *temp_filename = tmp_filename;
752 struct stat tmp_statbuf;
753 char *backup_filename;
756 backup_filename = create_backup_filename (filename);
758 if (unlink (backup_filename) == -1 && errno != ENOENT)
762 G_IO_ERROR_CANT_CREATE_BACKUP,
763 _("Backup file creation failed"));
764 g_free (backup_filename);
768 bfd = g_open (backup_filename,
769 O_WRONLY | O_CREAT | O_EXCL,
770 original_stat.st_mode & 0777);
776 G_IO_ERROR_CANT_CREATE_BACKUP,
777 _("Backup file creation failed"));
778 g_free (backup_filename);
782 /* If needed, Try to set the group of the backup same as the
783 * original file. If this fails, set the protection
784 * bits for the group same as the protection bits for
786 #if defined(HAVE_FCHOWN) && defined(HAVE_FCHMOD)
787 if (fstat (bfd, &tmp_statbuf) != 0)
791 G_IO_ERROR_CANT_CREATE_BACKUP,
792 _("Backup file creation failed"));
793 unlink (backup_filename);
794 g_free (backup_filename);
798 if ((original_stat.st_gid != tmp_statbuf.st_gid) &&
799 fchown (bfd, (uid_t) -1, original_stat.st_gid) != 0)
802 (original_stat.st_mode & 0707) |
803 ((original_stat.st_mode & 07) << 3)) != 0)
807 G_IO_ERROR_CANT_CREATE_BACKUP,
808 _("Backup file creation failed"));
809 unlink (backup_filename);
811 g_free (backup_filename);
817 if (!copy_file_data (fd, bfd, NULL))
821 G_IO_ERROR_CANT_CREATE_BACKUP,
822 _("Backup file creation failed"));
823 unlink (backup_filename);
825 g_free (backup_filename);
831 g_free (backup_filename);
833 /* Seek back to the start of the file after the backup copy */
834 if (lseek (fd, 0, SEEK_SET) == -1)
838 g_set_error (error, G_IO_ERROR,
839 g_io_error_from_errno (errsv),
840 _("Error seeking in file: %s"),
846 /* Truncate the file at the start */
848 if (g_win32_ftruncate (fd, 0) == -1)
850 if (ftruncate (fd, 0) == -1)
855 g_set_error (error, G_IO_ERROR,
856 g_io_error_from_errno (errsv),
857 _("Error truncating file: %s"),
870 _g_local_file_output_stream_replace (const char *filename,
872 gboolean create_backup,
873 GFileCreateFlags flags,
874 GCancellable *cancellable,
877 GLocalFileOutputStream *stream;
882 if (g_cancellable_set_error_if_cancelled (cancellable, error))
887 if (flags & G_FILE_CREATE_PRIVATE)
892 /* If the file doesn't exist, create it */
893 fd = g_open (filename, O_CREAT | O_EXCL | O_WRONLY, mode);
895 if (fd == -1 && errno == EEXIST)
897 /* The file already exists */
898 fd = handle_overwrite_open (filename, etag, create_backup, &temp_file,
908 /* This must be an invalid filename, on e.g. FAT */
909 g_set_error (error, G_IO_ERROR,
910 G_IO_ERROR_INVALID_FILENAME,
911 _("Invalid filename"));
913 g_set_error (error, G_IO_ERROR,
914 g_io_error_from_errno (errsv),
915 _("Error opening file '%s': %s"),
916 filename, g_strerror (errsv));
921 stream = g_object_new (G_TYPE_LOCAL_FILE_OUTPUT_STREAM, NULL);
922 stream->priv->fd = fd;
923 stream->priv->tmp_filename = temp_file;
925 stream->priv->backup_filename = create_backup_filename (filename);
926 stream->priv->original_filename = g_strdup (filename);
928 return G_FILE_OUTPUT_STREAM (stream);