D-Bus  1.13.7
dbus-file-unix.c
1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-file-unix.c unix related file implementation (internal to D-Bus implementation)
3  *
4  * Copyright (C) 2002, 2003, 2006 Red Hat, Inc.
5  * Copyright (C) 2003 CodeFactory AB
6  *
7  * Licensed under the Academic Free License version 2.1
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  *
23  */
24 
25 #include <config.h>
26 
27 #include "dbus-protocol.h"
28 #include "dbus-errors.h"
29 #include "dbus-file.h"
30 #include "dbus-internals.h"
31 #include "dbus-sysdeps.h"
32 #include "dbus-sysdeps-unix.h"
33 
34 #include <sys/stat.h>
35 #include <stdio.h>
36 #include <fcntl.h>
37 #include <unistd.h>
38 #include <errno.h>
39 
40 #ifndef O_BINARY
41 #define O_BINARY 0
42 #endif
43 
56  const DBusString *filename,
57  DBusError *error)
58 {
59  int fd;
60  struct stat sb;
61  int orig_len;
62  int total;
63  const char *filename_c;
64 
65  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
66 
67  filename_c = _dbus_string_get_const_data (filename);
68 
69  /* O_BINARY useful on Cygwin */
70  fd = open (filename_c, O_RDONLY | O_BINARY);
71  if (fd < 0)
72  {
73  dbus_set_error (error, _dbus_error_from_errno (errno),
74  "Failed to open \"%s\": %s",
75  filename_c,
76  _dbus_strerror (errno));
77  return FALSE;
78  }
79 
80  _dbus_verbose ("file fd %d opened\n", fd);
81 
82  if (fstat (fd, &sb) < 0)
83  {
84  dbus_set_error (error, _dbus_error_from_errno (errno),
85  "Failed to stat \"%s\": %s",
86  filename_c,
87  _dbus_strerror (errno));
88 
89  _dbus_verbose ("fstat() failed: %s",
90  _dbus_strerror (errno));
91 
92  _dbus_close (fd, NULL);
93 
94  return FALSE;
95  }
96 
97  if (sb.st_size > _DBUS_ONE_MEGABYTE)
98  {
100  "File size %lu of \"%s\" is too large.",
101  (unsigned long) sb.st_size, filename_c);
102  _dbus_close (fd, NULL);
103  return FALSE;
104  }
105 
106  total = 0;
107  orig_len = _dbus_string_get_length (str);
108  if (sb.st_size > 0 && S_ISREG (sb.st_mode))
109  {
110  int bytes_read;
111 
112  while (total < (int) sb.st_size)
113  {
114  bytes_read = _dbus_read (fd, str,
115  sb.st_size - total);
116  if (bytes_read <= 0)
117  {
118  dbus_set_error (error, _dbus_error_from_errno (errno),
119  "Error reading \"%s\": %s",
120  filename_c,
121  _dbus_strerror (errno));
122 
123  _dbus_verbose ("read() failed: %s",
124  _dbus_strerror (errno));
125 
126  _dbus_close (fd, NULL);
127  _dbus_string_set_length (str, orig_len);
128  return FALSE;
129  }
130  else
131  total += bytes_read;
132  }
133 
134  _dbus_close (fd, NULL);
135  return TRUE;
136  }
137  else if (sb.st_size != 0)
138  {
139  _dbus_verbose ("Can only open regular files at the moment.\n");
141  "\"%s\" is not a regular file",
142  filename_c);
143  _dbus_close (fd, NULL);
144  return FALSE;
145  }
146  else
147  {
148  _dbus_close (fd, NULL);
149  return TRUE;
150  }
151 }
152 
165  const DBusString *filename,
166  dbus_bool_t world_readable,
167  DBusError *error)
168 {
169  int fd;
170  int bytes_to_write;
171  const char *filename_c;
172  DBusString tmp_filename;
173  const char *tmp_filename_c;
174  int total;
175  dbus_bool_t need_unlink;
176  dbus_bool_t retval;
177 
178  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
179 
180  fd = -1;
181  retval = FALSE;
182  need_unlink = FALSE;
183 
184  if (!_dbus_string_init (&tmp_filename))
185  {
187  return FALSE;
188  }
189 
190  if (!_dbus_string_copy (filename, 0, &tmp_filename, 0))
191  {
193  _dbus_string_free (&tmp_filename);
194  return FALSE;
195  }
196 
197  if (!_dbus_string_append (&tmp_filename, "."))
198  {
200  _dbus_string_free (&tmp_filename);
201  return FALSE;
202  }
203 
204 #define N_TMP_FILENAME_RANDOM_BYTES 8
205  if (!_dbus_generate_random_ascii (&tmp_filename, N_TMP_FILENAME_RANDOM_BYTES,
206  error))
207  {
208  _dbus_string_free (&tmp_filename);
209  return FALSE;
210  }
211 
212  filename_c = _dbus_string_get_const_data (filename);
213  tmp_filename_c = _dbus_string_get_const_data (&tmp_filename);
214 
215  fd = open (tmp_filename_c, O_WRONLY | O_BINARY | O_EXCL | O_CREAT,
216  world_readable ? 0644 : 0600);
217  if (fd < 0)
218  {
219  dbus_set_error (error, _dbus_error_from_errno (errno),
220  "Could not create %s: %s", tmp_filename_c,
221  _dbus_strerror (errno));
222  goto out;
223  }
224  if (world_readable)
225  {
226  /* Ensure the file is world readable even in the presence of
227  * possibly restrictive umasks;
228  * see http://lists.freedesktop.org/archives/dbus/2010-September/013367.html
229  */
230  if (fchmod (fd, 0644) < 0)
231  {
232  dbus_set_error (error, _dbus_error_from_errno (errno),
233  "Could not chmod %s: %s", tmp_filename_c,
234  _dbus_strerror (errno));
235  goto out;
236  }
237  }
238 
239  _dbus_verbose ("tmp file fd %d opened\n", fd);
240 
241  need_unlink = TRUE;
242 
243  total = 0;
244  bytes_to_write = _dbus_string_get_length (str);
245 
246  while (total < bytes_to_write)
247  {
248  int bytes_written;
249 
250  bytes_written = _dbus_write (fd, str, total,
251  bytes_to_write - total);
252 
253  if (bytes_written <= 0)
254  {
255  dbus_set_error (error, _dbus_error_from_errno (errno),
256  "Could not write to %s: %s", tmp_filename_c,
257  _dbus_strerror (errno));
258 
259  goto out;
260  }
261 
262  total += bytes_written;
263  }
264 
265  if (fsync(fd))
266  {
267  dbus_set_error (error, _dbus_error_from_errno (errno),
268  "Could not synchronize file %s: %s",
269  tmp_filename_c, _dbus_strerror (errno));
270 
271  goto out;
272  }
273 
274  if (!_dbus_close (fd, NULL))
275  {
276  dbus_set_error (error, _dbus_error_from_errno (errno),
277  "Could not close file %s: %s",
278  tmp_filename_c, _dbus_strerror (errno));
279 
280  goto out;
281  }
282 
283  fd = -1;
284 
285  if (rename (tmp_filename_c, filename_c) < 0)
286  {
287  dbus_set_error (error, _dbus_error_from_errno (errno),
288  "Could not rename %s to %s: %s",
289  tmp_filename_c, filename_c,
290  _dbus_strerror (errno));
291 
292  goto out;
293  }
294 
295  need_unlink = FALSE;
296 
297  retval = TRUE;
298 
299  out:
300  /* close first, then unlink, to prevent ".nfs34234235" garbage
301  * files
302  */
303 
304  if (fd >= 0)
305  _dbus_close (fd, NULL);
306 
307  if (need_unlink && unlink (tmp_filename_c) < 0)
308  _dbus_verbose ("Failed to unlink temp file %s: %s\n",
309  tmp_filename_c, _dbus_strerror (errno));
310 
311  _dbus_string_free (&tmp_filename);
312 
313  _DBUS_ASSERT_ERROR_XOR_BOOL (error, retval);
314  return retval;
315 }
316 
325  DBusError *error)
326 {
327  const char *filename_c;
328 
329  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
330 
331  filename_c = _dbus_string_get_const_data (filename);
332  if (chmod (filename_c, 0644) == -1)
333  {
334  dbus_set_error (error,
336  "Could not change permissions of file %s: %s\n",
337  filename_c,
338  _dbus_strerror (errno));
339  return FALSE;
340  }
341  return TRUE;
342 }
343 
352  DBusError *error)
353 {
354  int fd;
355  const char *filename_c;
356 
357  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
358 
359  filename_c = _dbus_string_get_const_data (filename);
360 
361  fd = open (filename_c, O_WRONLY | O_BINARY | O_EXCL | O_CREAT,
362  0600);
363  if (fd < 0)
364  {
365  dbus_set_error (error,
367  "Could not create file %s: %s\n",
368  filename_c,
369  _dbus_strerror (errno));
370  return FALSE;
371  }
372 
373  _dbus_verbose ("exclusive file fd %d opened\n", fd);
374 
375  if (!_dbus_close (fd, NULL))
376  {
377  dbus_set_error (error,
379  "Could not close file %s: %s\n",
380  filename_c,
381  _dbus_strerror (errno));
382  return FALSE;
383  }
384 
385  return TRUE;
386 }
387 
397 _dbus_delete_file (const DBusString *filename,
398  DBusError *error)
399 {
400  const char *filename_c;
401 
402  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
403 
404  filename_c = _dbus_string_get_const_data (filename);
405 
406  if (unlink (filename_c) < 0)
407  {
409  "Failed to delete file %s: %s\n",
410  filename_c, _dbus_strerror (errno));
411  return FALSE;
412  }
413  else
414  return TRUE;
415 }
dbus_bool_t _dbus_string_append(DBusString *str, const char *buffer)
Appends a nul-terminated C-style string to a DBusString.
Definition: dbus-string.c:952
#define NULL
A null pointer, defined appropriately for C or C++.
dbus_bool_t _dbus_create_file_exclusively(const DBusString *filename, DBusError *error)
Creates the given file, failing if the file already exists.
dbus_bool_t _dbus_string_save_to_file(const DBusString *str, const DBusString *filename, dbus_bool_t world_readable, DBusError *error)
Writes a string out to a file.
int _dbus_write(int fd, const DBusString *buffer, int start, int len)
Thin wrapper around the write() system call that writes a part of a DBusString and handles EINTR for ...
dbus_bool_t _dbus_file_get_contents(DBusString *str, const DBusString *filename, DBusError *error)
Appends the contents of the given file to the string, returning error code.
dbus_bool_t _dbus_string_init(DBusString *str)
Initializes a string.
Definition: dbus-string.c:175
dbus_bool_t _dbus_string_copy(const DBusString *source, int start, DBusString *dest, int insert_at)
Like _dbus_string_move(), but does not delete the section of the source string that&#39;s copied to the d...
Definition: dbus-string.c:1300
dbus_bool_t _dbus_delete_file(const DBusString *filename, DBusError *error)
Deletes the given file.
const char * _dbus_error_from_errno(int error_number)
Converts a UNIX errno, or Windows errno or WinSock error value into a DBusError name.
Definition: dbus-sysdeps.c:599
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:35
dbus_bool_t _dbus_generate_random_ascii(DBusString *str, int n_bytes, DBusError *error)
Generates the given number of random bytes, where the bytes are chosen from the alphanumeric ASCII su...
Definition: dbus-sysdeps.c:559
dbus_bool_t _dbus_make_file_world_readable(const DBusString *filename, DBusError *error)
Makes the file readable by every user in the system.
int _dbus_read(int fd, DBusString *buffer, int count)
Thin wrapper around the read() system call that appends the data it reads to the DBusString buffer...
Object representing an exception.
Definition: dbus-errors.h:48
void dbus_set_error(DBusError *error, const char *name, const char *format,...)
Assigns an error name and message to a DBusError.
Definition: dbus-errors.c:354
void _dbus_string_free(DBusString *str)
Frees a string created by _dbus_string_init(), and fills it with the same contents as #_DBUS_STRING_I...
Definition: dbus-string.c:264
#define TRUE
Expands to "1".
#define DBUS_ERROR_FAILED
A generic error; "something went wrong" - see the error message for more.
#define DBUS_ERROR_NO_MEMORY
There was not enough memory to complete an operation.
dbus_bool_t _dbus_close(int fd, DBusError *error)
Closes a file descriptor.
#define FALSE
Expands to "0".
dbus_bool_t _dbus_string_set_length(DBusString *str, int length)
Sets the length of a string.
Definition: dbus-string.c:819