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);
164 g_set_error (error, G_IO_ERROR,
165 g_io_error_from_errno (errno),
166 _("Error writing to file: %s"),
177 g_local_file_output_stream_close (GOutputStream *stream,
178 GCancellable *cancellable,
181 GLocalFileOutputStream *file;
182 struct stat final_stat;
185 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
187 if (file->priv->tmp_filename)
189 /* We need to move the temp file to its final place,
190 * and possibly create the backup file
193 if (file->priv->backup_filename)
195 if (g_cancellable_set_error_if_cancelled (cancellable, error))
199 /* create original -> backup link, the original is then renamed over */
200 if (unlink (file->priv->backup_filename) != 0 &&
203 g_set_error (error, G_IO_ERROR,
204 G_IO_ERROR_CANT_CREATE_BACKUP,
205 _("Error removing old backup link: %s"),
210 if (link (file->priv->original_filename, file->priv->backup_filename) != 0)
212 /* link failed or is not supported, try rename */
213 if (rename (file->priv->original_filename, file->priv->backup_filename) != 0)
215 g_set_error (error, G_IO_ERROR,
216 G_IO_ERROR_CANT_CREATE_BACKUP,
217 _("Error creating backup copy: %s"),
223 /* If link not supported, just rename... */
224 if (rename (file->priv->original_filename, file->priv->backup_filename) != 0)
226 g_set_error (error, G_IO_ERROR,
227 G_IO_ERROR_CANT_CREATE_BACKUP,
228 _("Error creating backup copy: %s"),
236 if (g_cancellable_set_error_if_cancelled (cancellable, error))
239 /* tmp -> original */
240 if (rename (file->priv->tmp_filename, file->priv->original_filename) != 0)
242 g_set_error (error, G_IO_ERROR,
243 g_io_error_from_errno (errno),
244 _("Error renaming temporary file: %s"),
250 if (g_cancellable_set_error_if_cancelled (cancellable, error))
253 if (fstat (file->priv->fd, &final_stat) == 0)
254 file->priv->etag = _g_local_file_info_create_etag (&final_stat);
258 res = close (file->priv->fd);
261 g_set_error (error, G_IO_ERROR,
262 g_io_error_from_errno (errno),
263 _("Error closing file: %s"),
272 /* A simple try to close the fd in case we fail before the actual close */
273 close (file->priv->fd);
278 g_local_file_output_stream_get_etag (GFileOutputStream *stream)
280 GLocalFileOutputStream *file;
282 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
284 return g_strdup (file->priv->etag);
288 g_local_file_output_stream_tell (GFileOutputStream *stream)
290 GLocalFileOutputStream *file;
293 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
295 pos = lseek (file->priv->fd, 0, SEEK_CUR);
297 if (pos == (off_t)-1)
304 g_local_file_output_stream_can_seek (GFileOutputStream *stream)
306 GLocalFileOutputStream *file;
309 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
311 pos = lseek (file->priv->fd, 0, SEEK_CUR);
313 if (pos == (off_t)-1 && errno == ESPIPE)
320 seek_type_to_lseek (GSeekType type)
337 g_local_file_output_stream_seek (GFileOutputStream *stream,
340 GCancellable *cancellable,
343 GLocalFileOutputStream *file;
346 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
348 pos = lseek (file->priv->fd, offset, seek_type_to_lseek (type));
350 if (pos == (off_t)-1)
352 g_set_error (error, G_IO_ERROR,
353 g_io_error_from_errno (errno),
354 _("Error seeking in file: %s"),
363 g_local_file_output_stream_can_truncate (GFileOutputStream *stream)
365 /* We can't truncate pipes and stuff where we can't seek */
366 return g_local_file_output_stream_can_seek (stream);
370 g_local_file_output_stream_truncate (GFileOutputStream *stream,
372 GCancellable *cancellable,
375 GLocalFileOutputStream *file;
378 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
382 res = g_win32_ftruncate (file->priv->fd, size);
384 res = ftruncate (file->priv->fd, size);
391 if (g_cancellable_set_error_if_cancelled (cancellable, error))
396 g_set_error (error, G_IO_ERROR,
397 g_io_error_from_errno (errno),
398 _("Error truncating file: %s"),
408 g_local_file_output_stream_query_info (GFileOutputStream *stream,
410 GCancellable *cancellable,
413 GLocalFileOutputStream *file;
415 file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
417 if (g_cancellable_set_error_if_cancelled (cancellable, error))
420 return _g_local_file_info_get_from_fd (file->priv->fd,
426 _g_local_file_output_stream_create (const char *filename,
427 GFileCreateFlags flags,
428 GCancellable *cancellable,
431 GLocalFileOutputStream *stream;
435 if (g_cancellable_set_error_if_cancelled (cancellable, error))
438 if (flags & G_FILE_CREATE_PRIVATE)
443 fd = g_open (filename, O_CREAT | O_EXCL | O_WRONLY, mode);
449 /* This must be an invalid filename, on e.g. FAT */
450 g_set_error (error, G_IO_ERROR,
451 G_IO_ERROR_INVALID_FILENAME,
452 _("Invalid filename"));
454 g_set_error (error, G_IO_ERROR,
455 g_io_error_from_errno (errsv),
456 _("Error opening file '%s': %s"),
457 filename, g_strerror (errsv));
461 stream = g_object_new (G_TYPE_LOCAL_FILE_OUTPUT_STREAM, NULL);
462 stream->priv->fd = fd;
463 return G_FILE_OUTPUT_STREAM (stream);
467 _g_local_file_output_stream_append (const char *filename,
468 GFileCreateFlags flags,
469 GCancellable *cancellable,
472 GLocalFileOutputStream *stream;
476 if (g_cancellable_set_error_if_cancelled (cancellable, error))
479 if (flags & G_FILE_CREATE_PRIVATE)
484 fd = g_open (filename, O_CREAT | O_APPEND | O_WRONLY, mode);
490 /* This must be an invalid filename, on e.g. FAT */
491 g_set_error (error, G_IO_ERROR,
492 G_IO_ERROR_INVALID_FILENAME,
493 _("Invalid filename"));
495 g_set_error (error, G_IO_ERROR,
496 g_io_error_from_errno (errsv),
497 _("Error opening file '%s': %s"),
498 filename, g_strerror (errsv));
502 stream = g_object_new (G_TYPE_LOCAL_FILE_OUTPUT_STREAM, NULL);
503 stream->priv->fd = fd;
505 return G_FILE_OUTPUT_STREAM (stream);
509 create_backup_filename (const char *filename)
511 return g_strconcat (filename, BACKUP_EXTENSION, NULL);
514 #define BUFSIZE 8192 /* size of normal write buffer */
517 copy_file_data (gint sfd,
523 const gchar *write_buffer;
525 gssize bytes_to_write;
526 gssize bytes_written;
528 buffer = g_malloc (BUFSIZE);
532 bytes_read = read (sfd, buffer, BUFSIZE);
533 if (bytes_read == -1)
538 g_set_error (error, G_IO_ERROR,
539 g_io_error_from_errno (errno),
540 _("Error reading from file: %s"),
546 bytes_to_write = bytes_read;
547 write_buffer = buffer;
551 bytes_written = write (dfd, write_buffer, bytes_to_write);
552 if (bytes_written == -1)
557 g_set_error (error, G_IO_ERROR,
558 g_io_error_from_errno (errno),
559 _("Error writing to file: %s"),
565 bytes_to_write -= bytes_written;
566 write_buffer += bytes_written;
568 while (bytes_to_write > 0);
570 } while ((bytes_read != 0) && (ret == TRUE));
578 handle_overwrite_open (const char *filename,
580 gboolean create_backup,
581 char **temp_filename,
582 GCancellable *cancellable,
586 struct stat original_stat;
591 /* We only need read access to the original file if we are creating a backup.
592 * We also add O_CREATE to avoid a race if the file was just removed */
594 open_flags = O_RDWR | O_CREAT;
596 open_flags = O_WRONLY | O_CREAT;
598 /* Some systems have O_NOFOLLOW, which lets us avoid some races
599 * when finding out if the file we opened was a symlink */
602 fd = g_open (filename, open_flags | O_NOFOLLOW, 0666);
603 if (fd == -1 && errno == ELOOP)
605 /* Could be a symlink, or it could be a regular ELOOP error,
606 * but then the next open will fail too. */
608 fd = g_open (filename, open_flags, 0666);
611 fd = g_open (filename, open_flags, 0666);
612 /* This is racy, but we do it as soon as possible to minimize the race */
613 is_symlink = g_file_test (filename, G_FILE_TEST_IS_SYMLINK);
618 g_set_error (error, G_IO_ERROR,
619 g_io_error_from_errno (errno),
620 _("Error opening file '%s': %s"),
621 filename, g_strerror (errno));
625 if (fstat (fd, &original_stat) != 0)
627 g_set_error (error, G_IO_ERROR,
628 g_io_error_from_errno (errno),
629 _("Error stating file '%s': %s"),
630 filename, g_strerror (errno));
634 /* not a regular file */
635 if (!S_ISREG (original_stat.st_mode))
637 if (S_ISDIR (original_stat.st_mode))
640 G_IO_ERROR_IS_DIRECTORY,
641 _("Target file is a directory"));
645 G_IO_ERROR_NOT_REGULAR_FILE,
646 _("Target file is not a regular file"));
652 current_etag = _g_local_file_info_create_etag (&original_stat);
653 if (strcmp (etag, current_etag) != 0)
657 G_IO_ERROR_WRONG_ETAG,
658 _("The file was externally modified"));
659 g_free (current_etag);
662 g_free (current_etag);
665 /* We use two backup strategies.
666 * The first one (which is faster) consist in saving to a
667 * tmp file then rename the original file to the backup and the
668 * tmp file to the original name. This is fast but doesn't work
669 * when the file is a link (hard or symbolic) or when we can't
670 * write to the current dir or can't set the permissions on the
672 * The second strategy consist simply in copying the old file
673 * to a backup file and rewrite the contents of the file.
676 if (!(original_stat.st_nlink > 1) && !is_symlink)
678 char *dirname, *tmp_filename;
681 dirname = g_path_get_dirname (filename);
682 tmp_filename = g_build_filename (dirname, ".goutputstream-XXXXXX", NULL);
685 tmpfd = g_mkstemp (tmp_filename);
688 g_free (tmp_filename);
689 goto fallback_strategy;
692 /* try to keep permissions */
696 fchown (tmpfd, original_stat.st_uid, original_stat.st_gid) == -1 ||
699 fchmod (tmpfd, original_stat.st_mode) == -1 ||
704 struct stat tmp_statbuf;
706 /* Check that we really needed to change something */
707 if (fstat (tmpfd, &tmp_statbuf) != 0 ||
708 original_stat.st_uid != tmp_statbuf.st_uid ||
709 original_stat.st_gid != tmp_statbuf.st_gid ||
710 original_stat.st_mode != tmp_statbuf.st_mode)
713 unlink (tmp_filename);
714 g_free (tmp_filename);
715 goto fallback_strategy;
720 *temp_filename = tmp_filename;
728 struct stat tmp_statbuf;
729 char *backup_filename;
732 backup_filename = create_backup_filename (filename);
734 if (unlink (backup_filename) == -1 && errno != ENOENT)
738 G_IO_ERROR_CANT_CREATE_BACKUP,
739 _("Backup file creation failed"));
740 g_free (backup_filename);
744 bfd = g_open (backup_filename,
745 O_WRONLY | O_CREAT | O_EXCL,
746 original_stat.st_mode & 0777);
752 G_IO_ERROR_CANT_CREATE_BACKUP,
753 _("Backup file creation failed"));
754 g_free (backup_filename);
758 /* If needed, Try to set the group of the backup same as the
759 * original file. If this fails, set the protection
760 * bits for the group same as the protection bits for
763 if (fstat (bfd, &tmp_statbuf) != 0)
767 G_IO_ERROR_CANT_CREATE_BACKUP,
768 _("Backup file creation failed"));
769 unlink (backup_filename);
770 g_free (backup_filename);
774 if ((original_stat.st_gid != tmp_statbuf.st_gid) &&
775 fchown (bfd, (uid_t) -1, original_stat.st_gid) != 0)
778 (original_stat.st_mode & 0707) |
779 ((original_stat.st_mode & 07) << 3)) != 0)
783 G_IO_ERROR_CANT_CREATE_BACKUP,
784 _("Backup file creation failed"));
785 unlink (backup_filename);
787 g_free (backup_filename);
793 if (!copy_file_data (fd, bfd, NULL))
797 G_IO_ERROR_CANT_CREATE_BACKUP,
798 _("Backup file creation failed"));
799 unlink (backup_filename);
801 g_free (backup_filename);
807 g_free (backup_filename);
809 /* Seek back to the start of the file after the backup copy */
810 if (lseek (fd, 0, SEEK_SET) == -1)
812 g_set_error (error, G_IO_ERROR,
813 g_io_error_from_errno (errno),
814 _("Error seeking in file: %s"),
820 /* Truncate the file at the start */
822 if (g_win32_ftruncate (fd, 0) == -1)
824 if (ftruncate (fd, 0) == -1)
827 g_set_error (error, G_IO_ERROR,
828 g_io_error_from_errno (errno),
829 _("Error truncating file: %s"),
842 _g_local_file_output_stream_replace (const char *filename,
844 gboolean create_backup,
845 GFileCreateFlags flags,
846 GCancellable *cancellable,
849 GLocalFileOutputStream *stream;
854 if (g_cancellable_set_error_if_cancelled (cancellable, error))
859 if (flags & G_FILE_CREATE_PRIVATE)
864 /* If the file doesn't exist, create it */
865 fd = g_open (filename, O_CREAT | O_EXCL | O_WRONLY, mode);
867 if (fd == -1 && errno == EEXIST)
869 /* The file already exists */
870 fd = handle_overwrite_open (filename, etag, create_backup, &temp_file,
880 /* This must be an invalid filename, on e.g. FAT */
881 g_set_error (error, G_IO_ERROR,
882 G_IO_ERROR_INVALID_FILENAME,
883 _("Invalid filename"));
885 g_set_error (error, G_IO_ERROR,
886 g_io_error_from_errno (errsv),
887 _("Error opening file '%s': %s"),
888 filename, g_strerror (errsv));
893 stream = g_object_new (G_TYPE_LOCAL_FILE_OUTPUT_STREAM, NULL);
894 stream->priv->fd = fd;
895 stream->priv->tmp_filename = temp_file;
897 stream->priv->backup_filename = create_backup_filename (filename);
898 stream->priv->original_filename = g_strdup (filename);
900 return G_FILE_OUTPUT_STREAM (stream);