D-Bus: dbus-file-unix.c Source File

D-Bus 1.16.2

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 * SPDX-License-Identifier: AFL-2.1 OR GPL-2.0-or-later
8 *
9 * Licensed under the Academic Free License version 2.1
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 *
25 */
26
27#include <config.h>
28
29#include "dbus-protocol.h"
30#include "dbus-errors.h"
31#include "dbus-file.h"
32#include "dbus-internals.h"
33#include "dbus-sysdeps.h"
34#include "dbus-sysdeps-unix.h"
35
36#ifdef HAVE_LINUX_MAGIC_H
37#include <linux/magic.h>
38#endif
39#include <sys/stat.h>
40#ifdef HAVE_SYS_VFS_H
41#include <sys/vfs.h>
42#endif
43#include <stdio.h>
44#include <fcntl.h>
45#include <unistd.h>
46#include <errno.h>
47
48#ifndef O_BINARY
49#define O_BINARY 0
50#endif
51
62 dbus_bool_t
63_dbus_file_get_contents (DBusString *str,
64 const DBusString *filename,
65 DBusError *error)
66{
67 int fd;
68 struct stat sb;
69#if defined(HAVE_FSTATFS) && defined(PROC_SUPER_MAGIC)
70 struct statfs sfs;
71#endif
72 int orig_len;
73 int total;
74 int file_size;
75 const char *filename_c;
76 dbus_bool_t is_procfs = FALSE;
77
78 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
79
80 filename_c = _dbus_string_get_const_data (filename);
81
82 /* O_BINARY useful on Cygwin */
83 fd = open (filename_c, O_RDONLY | O_BINARY);
84 if (fd < 0)
85 {
86 dbus_set_error (error, _dbus_error_from_errno (errno),
87 "Failed to open \"%s\": %s",
88 filename_c,
89 _dbus_strerror (errno));
90 return FALSE;
91 }
92
93 _dbus_verbose ("file fd %d opened\n", fd);
94
95 if (fstat (fd, &sb) < 0)
96 {
97 dbus_set_error (error, _dbus_error_from_errno (errno),
98 "Failed to stat \"%s\": %s",
99 filename_c,
100 _dbus_strerror (errno));
101
102 _dbus_verbose ("fstat() failed: %s",
103 _dbus_strerror (errno));
104
105 _dbus_close (fd, NULL);
106
107 return FALSE;
108 }
109
110 if (sb.st_size > _DBUS_ONE_MEGABYTE)
111 {
112 dbus_set_error (error, DBUS_ERROR_FAILED,
113 "File size %lu of \"%s\" is too large.",
114 (unsigned long) sb.st_size, filename_c);
115 _dbus_close (fd, NULL);
116 return FALSE;
117 }
118
119 /* procfs has different semantics - most files are 0 size,
120 * we can do only one read, and at most we can read 4M.
121 */
122#if defined(HAVE_FSTATFS) && defined(PROC_SUPER_MAGIC)
123 if (sb.st_size == 0)
124 {
125 if (fstatfs(fd, &sfs) < 0)
126 {
127 dbus_set_error (error, _dbus_error_from_errno (errno),
128 "Failed to stat \"%s\": %s",
129 filename_c,
130 _dbus_strerror (errno));
131
132 _dbus_verbose ("fstatvfs() failed: %s",
133 _dbus_strerror (errno));
134
135 _dbus_close (fd, NULL);
136
137 return FALSE;
138 }
139 if (sfs.f_type == PROC_SUPER_MAGIC)
140 is_procfs = TRUE;
141 }
142#endif
143
144 if (is_procfs)
145 file_size = _DBUS_ONE_MEGABYTE;
146 else
147 file_size = sb.st_size;
148
149 total = 0;
150 orig_len = _dbus_string_get_length (str);
151 if (file_size > 0 && S_ISREG (sb.st_mode))
152 {
153 int bytes_read;
154
155 do
156 {
157 bytes_read = _dbus_read (fd, str,
158 file_size - total);
159 if (bytes_read <= 0)
160 {
161 dbus_set_error (error, _dbus_error_from_errno (errno),
162 "Error reading \"%s\": %s",
163 filename_c,
164 _dbus_strerror (errno));
165
166 _dbus_verbose ("read() failed: %s",
167 _dbus_strerror (errno));
168
169 _dbus_close (fd, NULL);
170 _dbus_string_set_length (str, orig_len);
171 return FALSE;
172 }
173 else
174 total += bytes_read;
175 }
176 while (total < file_size && !is_procfs);
177
178 _dbus_close (fd, NULL);
179 return TRUE;
180 }
181 else if (file_size != 0)
182 {
183 _dbus_verbose ("Can only open regular files at the moment.\n");
184 dbus_set_error (error, DBUS_ERROR_FAILED,
185 "\"%s\" is not a regular file",
186 filename_c);
187 _dbus_close (fd, NULL);
188 return FALSE;
189 }
190 else
191 {
192 _dbus_close (fd, NULL);
193 return TRUE;
194 }
195}
196
207 dbus_bool_t
208_dbus_string_save_to_file (const DBusString *str,
209 const DBusString *filename,
210 dbus_bool_t world_readable,
211 DBusError *error)
212{
213 int fd;
214 int bytes_to_write;
215 const char *filename_c;
216 DBusString tmp_filename;
217 const char *tmp_filename_c;
218 int total;
219 dbus_bool_t need_unlink;
220 dbus_bool_t retval;
221
222 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
223
224 fd = -1;
225 retval = FALSE;
226 need_unlink = FALSE;
227
228 if (!_dbus_string_init (&tmp_filename))
229 {
230 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
231 return FALSE;
232 }
233
234 if (!_dbus_string_copy (filename, 0, &tmp_filename, 0))
235 {
236 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
237 _dbus_string_free (&tmp_filename);
238 return FALSE;
239 }
240
241 if (!_dbus_string_append (&tmp_filename, "."))
242 {
243 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
244 _dbus_string_free (&tmp_filename);
245 return FALSE;
246 }
247
248#define N_TMP_FILENAME_RANDOM_BYTES 8
249 if (!_dbus_generate_random_ascii (&tmp_filename, N_TMP_FILENAME_RANDOM_BYTES,
250 error))
251 {
252 _dbus_string_free (&tmp_filename);
253 return FALSE;
254 }
255
256 filename_c = _dbus_string_get_const_data (filename);
257 tmp_filename_c = _dbus_string_get_const_data (&tmp_filename);
258
259 fd = open (tmp_filename_c, O_WRONLY | O_BINARY | O_EXCL | O_CREAT,
260 world_readable ? 0644 : 0600);
261 if (fd < 0)
262 {
263 dbus_set_error (error, _dbus_error_from_errno (errno),
264 "Could not create %s: %s", tmp_filename_c,
265 _dbus_strerror (errno));
266 goto out;
267 }
268 if (world_readable)
269 {
270 /* Ensure the file is world readable even in the presence of
271 * possibly restrictive umasks;
272 * see http://lists.freedesktop.org/archives/dbus/2010-September/013367.html
273 */
274 if (fchmod (fd, 0644) < 0)
275 {
276 dbus_set_error (error, _dbus_error_from_errno (errno),
277 "Could not chmod %s: %s", tmp_filename_c,
278 _dbus_strerror (errno));
279 goto out;
280 }
281 }
282
283 _dbus_verbose ("tmp file fd %d opened\n", fd);
284
285 need_unlink = TRUE;
286
287 total = 0;
288 bytes_to_write = _dbus_string_get_length (str);
289
290 while (total < bytes_to_write)
291 {
292 int bytes_written;
293
294 bytes_written = _dbus_write (fd, str, total,
295 bytes_to_write - total);
296
297 if (bytes_written <= 0)
298 {
299 dbus_set_error (error, _dbus_error_from_errno (errno),
300 "Could not write to %s: %s", tmp_filename_c,
301 _dbus_strerror (errno));
302
303 goto out;
304 }
305
306 total += bytes_written;
307 }
308
309 if (fsync(fd))
310 {
311 dbus_set_error (error, _dbus_error_from_errno (errno),
312 "Could not synchronize file %s: %s",
313 tmp_filename_c, _dbus_strerror (errno));
314
315 goto out;
316 }
317
318 if (!_dbus_close (fd, NULL))
319 {
320 dbus_set_error (error, _dbus_error_from_errno (errno),
321 "Could not close file %s: %s",
322 tmp_filename_c, _dbus_strerror (errno));
323
324 goto out;
325 }
326
327 fd = -1;
328
329 if (rename (tmp_filename_c, filename_c) < 0)
330 {
331 dbus_set_error (error, _dbus_error_from_errno (errno),
332 "Could not rename %s to %s: %s",
333 tmp_filename_c, filename_c,
334 _dbus_strerror (errno));
335
336 goto out;
337 }
338
339 need_unlink = FALSE;
340
341 retval = TRUE;
342
343 out:
344 /* close first, then unlink, to prevent ".nfs34234235" garbage
345 * files
346 */
347
348 if (fd >= 0)
349 _dbus_close (fd, NULL);
350
351 if (need_unlink && unlink (tmp_filename_c) < 0)
352 _dbus_verbose ("Failed to unlink temp file %s: %s\n",
353 tmp_filename_c, _dbus_strerror (errno));
354
355 _dbus_string_free (&tmp_filename);
356
357 _DBUS_ASSERT_ERROR_XOR_BOOL (error, retval);
358 return retval;
359}
360
367 dbus_bool_t
368_dbus_make_file_world_readable(const DBusString *filename,
369 DBusError *error)
370{
371 const char *filename_c;
372
373 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
374
375 filename_c = _dbus_string_get_const_data (filename);
376 if (chmod (filename_c, 0644) == -1)
377 {
378 dbus_set_error (error,
379 DBUS_ERROR_FAILED,
380 "Could not change permissions of file %s: %s\n",
381 filename_c,
382 _dbus_strerror (errno));
383 return FALSE;
384 }
385 return TRUE;
386}
387
394 dbus_bool_t
395_dbus_create_file_exclusively (const DBusString *filename,
396 DBusError *error)
397{
398 int fd;
399 const char *filename_c;
400
401 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
402
403 filename_c = _dbus_string_get_const_data (filename);
404
405 fd = open (filename_c, O_WRONLY | O_BINARY | O_EXCL | O_CREAT,
406 0600);
407 if (fd < 0)
408 {
409 dbus_set_error (error,
410 DBUS_ERROR_FAILED,
411 "Could not create file %s: %s\n",
412 filename_c,
413 _dbus_strerror (errno));
414 return FALSE;
415 }
416
417 _dbus_verbose ("exclusive file fd %d opened\n", fd);
418
419 if (!_dbus_close (fd, NULL))
420 {
421 dbus_set_error (error,
422 DBUS_ERROR_FAILED,
423 "Could not close file %s: %s\n",
424 filename_c,
425 _dbus_strerror (errno));
426 return FALSE;
427 }
428
429 return TRUE;
430}
431
440 dbus_bool_t
441_dbus_delete_file (const DBusString *filename,
442 DBusError *error)
443{
444 const char *filename_c;
445
446 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
447
448 filename_c = _dbus_string_get_const_data (filename);
449
450 if (unlink (filename_c) < 0)
451 {
452 dbus_set_error (error, DBUS_ERROR_FAILED,
453 "Failed to delete file %s: %s\n",
454 filename_c, _dbus_strerror (errno));
455 return FALSE;
456 }
457 else
458 return TRUE;
459}
dbus_set_error
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:356
_dbus_delete_file
dbus_bool_t _dbus_delete_file(const DBusString *filename, DBusError *error)
Deletes the given file.
Definition dbus-file-unix.c:441
_dbus_create_file_exclusively
dbus_bool_t _dbus_create_file_exclusively(const DBusString *filename, DBusError *error)
Creates the given file, failing if the file already exists.
Definition dbus-file-unix.c:395
_dbus_string_save_to_file
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.
Definition dbus-file-unix.c:208
_dbus_make_file_world_readable
dbus_bool_t _dbus_make_file_world_readable(const DBusString *filename, DBusError *error)
Makes the file readable by every user in the system.
Definition dbus-file-unix.c:368
_dbus_file_get_contents
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.
Definition dbus-file-unix.c:63
_dbus_error_from_errno
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:565
_dbus_generate_random_ascii
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:525
NULL
#define NULL
A null pointer, defined appropriately for C or C++.
Definition dbus-macros.h:51
TRUE
#define TRUE
Expands to "1".
Definition dbus-macros.h:41
FALSE
#define FALSE
Expands to "0".
Definition dbus-macros.h:44
DBUS_ERROR_FAILED
#define DBUS_ERROR_FAILED
A generic error; "something went wrong" - see the error message for more.
Definition dbus-protocol.h:361
DBUS_ERROR_NO_MEMORY
#define DBUS_ERROR_NO_MEMORY
There was not enough memory to complete an operation.
Definition dbus-protocol.h:363
_dbus_string_set_length
dbus_bool_t _dbus_string_set_length(DBusString *str, int length)
Sets the length of a string.
Definition dbus-string.c:847
_dbus_string_append
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:980
_dbus_string_init
dbus_bool_t _dbus_string_init(DBusString *str)
Initializes a string.
Definition dbus-string.c:182
_dbus_string_copy
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's copied to the d...
Definition dbus-string.c:1345
_dbus_string_free
void _dbus_string_free(DBusString *str)
Frees a string created by _dbus_string_init(), and fills it with the same contents as _DBUS_STRING_IN...
Definition dbus-string.c:278
_dbus_close
dbus_bool_t _dbus_close(int fd, DBusError *error)
Closes a file descriptor.
Definition dbus-sysdeps-unix.c:3727
_dbus_write
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 ...
Definition dbus-sysdeps-unix.c:827
_dbus_read
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.
Definition dbus-sysdeps-unix.c:767
dbus_bool_t
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition dbus-types.h:37
DBusError
Object representing an exception.
Definition dbus-errors.h:51
DBusString
Definition dbus-string.h:47