D-Bus  1.12.2
dbus-sysdeps-util-unix.c
1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-sysdeps-util-unix.c Would be in dbus-sysdeps-unix.c, but not used in libdbus
3  *
4  * Copyright (C) 2002, 2003, 2004, 2005 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 #include "dbus-sysdeps.h"
27 #include "dbus-sysdeps-unix.h"
28 #include "dbus-internals.h"
29 #include "dbus-list.h"
30 #include "dbus-pipe.h"
31 #include "dbus-protocol.h"
32 #include "dbus-string.h"
33 #define DBUS_USERDB_INCLUDES_PRIVATE 1
34 #include "dbus-userdb.h"
35 #include "dbus-test.h"
36 
37 #include <sys/types.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <signal.h>
41 #include <unistd.h>
42 #include <stdio.h>
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <sys/stat.h>
46 #ifdef HAVE_SYS_RESOURCE_H
47 #include <sys/resource.h>
48 #endif
49 #include <grp.h>
50 #include <sys/socket.h>
51 #include <dirent.h>
52 #include <sys/un.h>
53 
54 #ifdef HAVE_SYS_SYSLIMITS_H
55 #include <sys/syslimits.h>
56 #endif
57 
58 #ifdef HAVE_SYSTEMD
59 #include <systemd/sd-daemon.h>
60 #endif
61 
62 #ifndef O_BINARY
63 #define O_BINARY 0
64 #endif
65 
83  DBusPipe *print_pid_pipe,
84  DBusError *error,
85  dbus_bool_t keep_umask)
86 {
87  const char *s;
88  pid_t child_pid;
89  DBusEnsureStandardFdsFlags flags;
90 
91  _dbus_verbose ("Becoming a daemon...\n");
92 
93  _dbus_verbose ("chdir to /\n");
94  if (chdir ("/") < 0)
95  {
97  "Could not chdir() to root directory");
98  return FALSE;
99  }
100 
101  _dbus_verbose ("forking...\n");
102  switch ((child_pid = fork ()))
103  {
104  case -1:
105  _dbus_verbose ("fork failed\n");
106  dbus_set_error (error, _dbus_error_from_errno (errno),
107  "Failed to fork daemon: %s", _dbus_strerror (errno));
108  return FALSE;
109  break;
110 
111  case 0:
112  _dbus_verbose ("in child, closing std file descriptors\n");
113 
114  flags = DBUS_FORCE_STDIN_NULL | DBUS_FORCE_STDOUT_NULL;
115  s = _dbus_getenv ("DBUS_DEBUG_OUTPUT");
116 
117  if (s == NULL || *s == '\0')
118  flags |= DBUS_FORCE_STDERR_NULL;
119  else
120  _dbus_verbose ("keeping stderr open due to DBUS_DEBUG_OUTPUT\n");
121 
122  if (!_dbus_ensure_standard_fds (flags, &s))
123  {
124  _dbus_warn ("%s: %s", s, _dbus_strerror (errno));
125  _exit (1);
126  }
127 
128  if (!keep_umask)
129  {
130  /* Get a predictable umask */
131  _dbus_verbose ("setting umask\n");
132  umask (022);
133  }
134 
135  _dbus_verbose ("calling setsid()\n");
136  if (setsid () == -1)
137  _dbus_assert_not_reached ("setsid() failed");
138 
139  break;
140 
141  default:
142  if (!_dbus_write_pid_to_file_and_pipe (pidfile, print_pid_pipe,
143  child_pid, error))
144  {
145  _dbus_verbose ("pid file or pipe write failed: %s\n",
146  error->message);
147  kill (child_pid, SIGTERM);
148  return FALSE;
149  }
150 
151  _dbus_verbose ("parent exiting\n");
152  _exit (0);
153  break;
154  }
155 
156  return TRUE;
157 }
158 
159 
168 static dbus_bool_t
169 _dbus_write_pid_file (const DBusString *filename,
170  unsigned long pid,
171  DBusError *error)
172 {
173  const char *cfilename;
174  int fd;
175  FILE *f;
176 
177  cfilename = _dbus_string_get_const_data (filename);
178 
179  fd = open (cfilename, O_WRONLY|O_CREAT|O_EXCL|O_BINARY, 0644);
180 
181  if (fd < 0)
182  {
183  dbus_set_error (error, _dbus_error_from_errno (errno),
184  "Failed to open \"%s\": %s", cfilename,
185  _dbus_strerror (errno));
186  return FALSE;
187  }
188 
189  if ((f = fdopen (fd, "w")) == NULL)
190  {
191  dbus_set_error (error, _dbus_error_from_errno (errno),
192  "Failed to fdopen fd %d: %s", fd, _dbus_strerror (errno));
193  _dbus_close (fd, NULL);
194  return FALSE;
195  }
196 
197  if (fprintf (f, "%lu\n", pid) < 0)
198  {
199  dbus_set_error (error, _dbus_error_from_errno (errno),
200  "Failed to write to \"%s\": %s", cfilename,
201  _dbus_strerror (errno));
202 
203  fclose (f);
204  return FALSE;
205  }
206 
207  if (fclose (f) == EOF)
208  {
209  dbus_set_error (error, _dbus_error_from_errno (errno),
210  "Failed to close \"%s\": %s", cfilename,
211  _dbus_strerror (errno));
212  return FALSE;
213  }
214 
215  return TRUE;
216 }
217 
231  DBusPipe *print_pid_pipe,
232  dbus_pid_t pid_to_write,
233  DBusError *error)
234 {
235  if (pidfile)
236  {
237  _dbus_verbose ("writing pid file %s\n", _dbus_string_get_const_data (pidfile));
238  if (!_dbus_write_pid_file (pidfile,
239  pid_to_write,
240  error))
241  {
242  _dbus_verbose ("pid file write failed\n");
243  _DBUS_ASSERT_ERROR_IS_SET(error);
244  return FALSE;
245  }
246  }
247  else
248  {
249  _dbus_verbose ("No pid file requested\n");
250  }
251 
252  if (print_pid_pipe != NULL && _dbus_pipe_is_valid (print_pid_pipe))
253  {
254  DBusString pid;
255  int bytes;
256 
257  _dbus_verbose ("writing our pid to pipe %d\n",
258  print_pid_pipe->fd);
259 
260  if (!_dbus_string_init (&pid))
261  {
262  _DBUS_SET_OOM (error);
263  return FALSE;
264  }
265 
266  if (!_dbus_string_append_int (&pid, pid_to_write) ||
267  !_dbus_string_append (&pid, "\n"))
268  {
269  _dbus_string_free (&pid);
270  _DBUS_SET_OOM (error);
271  return FALSE;
272  }
273 
274  bytes = _dbus_string_get_length (&pid);
275  if (_dbus_pipe_write (print_pid_pipe, &pid, 0, bytes, error) != bytes)
276  {
277  /* _dbus_pipe_write sets error only on failure, not short write */
278  if (error != NULL && !dbus_error_is_set(error))
279  {
281  "Printing message bus PID: did not write enough bytes\n");
282  }
283  _dbus_string_free (&pid);
284  return FALSE;
285  }
286 
287  _dbus_string_free (&pid);
288  }
289  else
290  {
291  _dbus_verbose ("No pid pipe to write to\n");
292  }
293 
294  return TRUE;
295 }
296 
304 _dbus_verify_daemon_user (const char *user)
305 {
306  DBusString u;
307 
308  _dbus_string_init_const (&u, user);
309 
311 }
312 
313 
314 /* The HAVE_LIBAUDIT case lives in selinux.c */
315 #ifndef HAVE_LIBAUDIT
316 
324 _dbus_change_to_daemon_user (const char *user,
325  DBusError *error)
326 {
327  dbus_uid_t uid;
328  dbus_gid_t gid;
329  DBusString u;
330 
331  _dbus_string_init_const (&u, user);
332 
333  if (!_dbus_get_user_id_and_primary_group (&u, &uid, &gid))
334  {
336  "User '%s' does not appear to exist?",
337  user);
338  return FALSE;
339  }
340 
341  /* setgroups() only works if we are a privileged process,
342  * so we don't return error on failure; the only possible
343  * failure is that we don't have perms to do it.
344  *
345  * not sure this is right, maybe if setuid()
346  * is going to work then setgroups() should also work.
347  */
348  if (setgroups (0, NULL) < 0)
349  _dbus_warn ("Failed to drop supplementary groups: %s",
350  _dbus_strerror (errno));
351 
352  /* Set GID first, or the setuid may remove our permission
353  * to change the GID
354  */
355  if (setgid (gid) < 0)
356  {
357  dbus_set_error (error, _dbus_error_from_errno (errno),
358  "Failed to set GID to %lu: %s", gid,
359  _dbus_strerror (errno));
360  return FALSE;
361  }
362 
363  if (setuid (uid) < 0)
364  {
365  dbus_set_error (error, _dbus_error_from_errno (errno),
366  "Failed to set UID to %lu: %s", uid,
367  _dbus_strerror (errno));
368  return FALSE;
369  }
370 
371  return TRUE;
372 }
373 #endif /* !HAVE_LIBAUDIT */
374 
375 #ifdef HAVE_SETRLIMIT
376 
377 /* We assume that if we have setrlimit, we also have getrlimit and
378  * struct rlimit.
379  */
380 
381 struct DBusRLimit {
382  struct rlimit lim;
383 };
384 
385 DBusRLimit *
386 _dbus_rlimit_save_fd_limit (DBusError *error)
387 {
388  DBusRLimit *self;
389 
390  self = dbus_new0 (DBusRLimit, 1);
391 
392  if (self == NULL)
393  {
394  _DBUS_SET_OOM (error);
395  return NULL;
396  }
397 
398  if (getrlimit (RLIMIT_NOFILE, &self->lim) < 0)
399  {
400  dbus_set_error (error, _dbus_error_from_errno (errno),
401  "Failed to get fd limit: %s", _dbus_strerror (errno));
402  dbus_free (self);
403  return NULL;
404  }
405 
406  return self;
407 }
408 
410 _dbus_rlimit_raise_fd_limit_if_privileged (unsigned int desired,
411  DBusError *error)
412 {
413  struct rlimit lim;
414 
415  /* No point to doing this practically speaking
416  * if we're not uid 0. We expect the system
417  * bus to use this before we change UID, and
418  * the session bus takes the Linux default,
419  * currently 1024 for cur and 4096 for max.
420  */
421  if (getuid () != 0)
422  {
423  /* not an error, we're probably the session bus */
424  return TRUE;
425  }
426 
427  if (getrlimit (RLIMIT_NOFILE, &lim) < 0)
428  {
429  dbus_set_error (error, _dbus_error_from_errno (errno),
430  "Failed to get fd limit: %s", _dbus_strerror (errno));
431  return FALSE;
432  }
433 
434  if (lim.rlim_cur == RLIM_INFINITY || lim.rlim_cur >= desired)
435  {
436  /* not an error, everything is fine */
437  return TRUE;
438  }
439 
440  /* Ignore "maximum limit", assume we have the "superuser"
441  * privileges. On Linux this is CAP_SYS_RESOURCE.
442  */
443  lim.rlim_cur = lim.rlim_max = desired;
444 
445  if (setrlimit (RLIMIT_NOFILE, &lim) < 0)
446  {
447  dbus_set_error (error, _dbus_error_from_errno (errno),
448  "Failed to set fd limit to %u: %s",
449  desired, _dbus_strerror (errno));
450  return FALSE;
451  }
452 
453  return TRUE;
454 }
455 
457 _dbus_rlimit_restore_fd_limit (DBusRLimit *saved,
458  DBusError *error)
459 {
460  if (setrlimit (RLIMIT_NOFILE, &saved->lim) < 0)
461  {
462  dbus_set_error (error, _dbus_error_from_errno (errno),
463  "Failed to restore old fd limit: %s",
464  _dbus_strerror (errno));
465  return FALSE;
466  }
467 
468  return TRUE;
469 }
470 
471 #else /* !HAVE_SETRLIMIT */
472 
473 static void
474 fd_limit_not_supported (DBusError *error)
475 {
477  "cannot change fd limit on this platform");
478 }
479 
480 DBusRLimit *
481 _dbus_rlimit_save_fd_limit (DBusError *error)
482 {
483  fd_limit_not_supported (error);
484  return NULL;
485 }
486 
488 _dbus_rlimit_raise_fd_limit_if_privileged (unsigned int desired,
489  DBusError *error)
490 {
491  fd_limit_not_supported (error);
492  return FALSE;
493 }
494 
496 _dbus_rlimit_restore_fd_limit (DBusRLimit *saved,
497  DBusError *error)
498 {
499  fd_limit_not_supported (error);
500  return FALSE;
501 }
502 
503 #endif
504 
505 void
506 _dbus_rlimit_free (DBusRLimit *lim)
507 {
508  dbus_free (lim);
509 }
510 
516 void
518  DBusSignalHandler handler)
519 {
520  struct sigaction act;
521  sigset_t empty_mask;
522 
523  sigemptyset (&empty_mask);
524  act.sa_handler = handler;
525  act.sa_mask = empty_mask;
526  act.sa_flags = 0;
527  sigaction (sig, &act, NULL);
528 }
529 
536 _dbus_file_exists (const char *file)
537 {
538  return (access (file, F_OK) == 0);
539 }
540 
548 _dbus_user_at_console (const char *username,
549  DBusError *error)
550 {
551 #ifdef DBUS_CONSOLE_AUTH_DIR
552  DBusString u, f;
553  dbus_bool_t result;
554 
555  result = FALSE;
556  if (!_dbus_string_init (&f))
557  {
558  _DBUS_SET_OOM (error);
559  return FALSE;
560  }
561 
562  if (!_dbus_string_append (&f, DBUS_CONSOLE_AUTH_DIR))
563  {
564  _DBUS_SET_OOM (error);
565  goto out;
566  }
567 
568  _dbus_string_init_const (&u, username);
569 
570  if (!_dbus_concat_dir_and_file (&f, &u))
571  {
572  _DBUS_SET_OOM (error);
573  goto out;
574  }
575 
576  result = _dbus_file_exists (_dbus_string_get_const_data (&f));
577 
578  out:
579  _dbus_string_free (&f);
580 
581  return result;
582 #else
583  return FALSE;
584 #endif
585 }
586 
587 
596 {
597  if (_dbus_string_get_length (filename) > 0)
598  return _dbus_string_get_byte (filename, 0) == '/';
599  else
600  return FALSE;
601 }
602 
612 _dbus_stat (const DBusString *filename,
613  DBusStat *statbuf,
614  DBusError *error)
615 {
616  const char *filename_c;
617  struct stat sb;
618 
619  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
620 
621  filename_c = _dbus_string_get_const_data (filename);
622 
623  if (stat (filename_c, &sb) < 0)
624  {
625  dbus_set_error (error, _dbus_error_from_errno (errno),
626  "%s", _dbus_strerror (errno));
627  return FALSE;
628  }
629 
630  statbuf->mode = sb.st_mode;
631  statbuf->nlink = sb.st_nlink;
632  statbuf->uid = sb.st_uid;
633  statbuf->gid = sb.st_gid;
634  statbuf->size = sb.st_size;
635  statbuf->atime = sb.st_atime;
636  statbuf->mtime = sb.st_mtime;
637  statbuf->ctime = sb.st_ctime;
638 
639  return TRUE;
640 }
641 
642 
647 {
648  DIR *d;
650 };
651 
661  DBusError *error)
662 {
663  DIR *d;
664  DBusDirIter *iter;
665  const char *filename_c;
666 
667  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
668 
669  filename_c = _dbus_string_get_const_data (filename);
670 
671  d = opendir (filename_c);
672  if (d == NULL)
673  {
674  dbus_set_error (error, _dbus_error_from_errno (errno),
675  "Failed to read directory \"%s\": %s",
676  filename_c,
677  _dbus_strerror (errno));
678  return NULL;
679  }
680  iter = dbus_new0 (DBusDirIter, 1);
681  if (iter == NULL)
682  {
683  closedir (d);
685  "Could not allocate memory for directory iterator");
686  return NULL;
687  }
688 
689  iter->d = d;
690 
691  return iter;
692 }
693 
709  DBusString *filename,
710  DBusError *error)
711 {
712  struct dirent *ent;
713  int err;
714 
715  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
716 
717  again:
718  errno = 0;
719  ent = readdir (iter->d);
720 
721  if (!ent)
722  {
723  err = errno;
724 
725  if (err != 0)
726  dbus_set_error (error,
728  "%s", _dbus_strerror (err));
729 
730  return FALSE;
731  }
732  else if (ent->d_name[0] == '.' &&
733  (ent->d_name[1] == '\0' ||
734  (ent->d_name[1] == '.' && ent->d_name[2] == '\0')))
735  goto again;
736  else
737  {
738  _dbus_string_set_length (filename, 0);
739  if (!_dbus_string_append (filename, ent->d_name))
740  {
742  "No memory to read directory entry");
743  return FALSE;
744  }
745  else
746  {
747  return TRUE;
748  }
749  }
750 }
751 
755 void
757 {
758  closedir (iter->d);
759  dbus_free (iter);
760 }
761 
762 static dbus_bool_t
763 fill_user_info_from_group (struct group *g,
764  DBusGroupInfo *info,
765  DBusError *error)
766 {
767  _dbus_assert (g->gr_name != NULL);
768 
769  info->gid = g->gr_gid;
770  info->groupname = _dbus_strdup (g->gr_name);
771 
772  /* info->members = dbus_strdupv (g->gr_mem) */
773 
774  if (info->groupname == NULL)
775  {
777  return FALSE;
778  }
779 
780  return TRUE;
781 }
782 
783 static dbus_bool_t
784 fill_group_info (DBusGroupInfo *info,
785  dbus_gid_t gid,
786  const DBusString *groupname,
787  DBusError *error)
788 {
789  const char *group_c_str;
790 
791  _dbus_assert (groupname != NULL || gid != DBUS_GID_UNSET);
792  _dbus_assert (groupname == NULL || gid == DBUS_GID_UNSET);
793 
794  if (groupname)
795  group_c_str = _dbus_string_get_const_data (groupname);
796  else
797  group_c_str = NULL;
798 
799  /* For now assuming that the getgrnam() and getgrgid() flavors
800  * always correspond to the pwnam flavors, if not we have
801  * to add more configure checks.
802  */
803 
804 #if defined (HAVE_POSIX_GETPWNAM_R) || defined (HAVE_NONPOSIX_GETPWNAM_R)
805  {
806  struct group *g;
807  int result;
808  size_t buflen;
809  char *buf;
810  struct group g_str;
811  dbus_bool_t b;
812 
813  /* retrieve maximum needed size for buf */
814  buflen = sysconf (_SC_GETGR_R_SIZE_MAX);
815 
816  /* sysconf actually returns a long, but everything else expects size_t,
817  * so just recast here.
818  * https://bugs.freedesktop.org/show_bug.cgi?id=17061
819  */
820  if ((long) buflen <= 0)
821  buflen = 1024;
822 
823  result = -1;
824  while (1)
825  {
826  buf = dbus_malloc (buflen);
827  if (buf == NULL)
828  {
830  return FALSE;
831  }
832 
833  g = NULL;
834 #ifdef HAVE_POSIX_GETPWNAM_R
835  if (group_c_str)
836  result = getgrnam_r (group_c_str, &g_str, buf, buflen,
837  &g);
838  else
839  result = getgrgid_r (gid, &g_str, buf, buflen,
840  &g);
841 #else
842  g = getgrnam_r (group_c_str, &g_str, buf, buflen);
843  result = 0;
844 #endif /* !HAVE_POSIX_GETPWNAM_R */
845  /* Try a bigger buffer if ERANGE was returned:
846  https://bugs.freedesktop.org/show_bug.cgi?id=16727
847  */
848  if (result == ERANGE && buflen < 512 * 1024)
849  {
850  dbus_free (buf);
851  buflen *= 2;
852  }
853  else
854  {
855  break;
856  }
857  }
858 
859  if (result == 0 && g == &g_str)
860  {
861  b = fill_user_info_from_group (g, info, error);
862  dbus_free (buf);
863  return b;
864  }
865  else
866  {
867  dbus_set_error (error, _dbus_error_from_errno (errno),
868  "Group %s unknown or failed to look it up\n",
869  group_c_str ? group_c_str : "???");
870  dbus_free (buf);
871  return FALSE;
872  }
873  }
874 #else /* ! HAVE_GETPWNAM_R */
875  {
876  /* I guess we're screwed on thread safety here */
877  struct group *g;
878 
879  g = getgrnam (group_c_str);
880 
881  if (g != NULL)
882  {
883  return fill_user_info_from_group (g, info, error);
884  }
885  else
886  {
887  dbus_set_error (error, _dbus_error_from_errno (errno),
888  "Group %s unknown or failed to look it up\n",
889  group_c_str ? group_c_str : "???");
890  return FALSE;
891  }
892  }
893 #endif /* ! HAVE_GETPWNAM_R */
894 }
895 
907  const DBusString *groupname,
908  DBusError *error)
909 {
910  return fill_group_info (info, DBUS_GID_UNSET,
911  groupname, error);
912 
913 }
914 
926  dbus_gid_t gid,
927  DBusError *error)
928 {
929  return fill_group_info (info, gid, NULL, error);
930 }
931 
942  dbus_uid_t *uid_p)
943 {
944  return _dbus_get_user_id (username, uid_p);
945 
946 }
947 
958  dbus_gid_t *gid_p)
959 {
960  return _dbus_get_group_id (groupname, gid_p);
961 }
962 
975  dbus_gid_t **group_ids,
976  int *n_group_ids)
977 {
978  return _dbus_groups_from_uid (uid, group_ids, n_group_ids);
979 }
980 
992  DBusError *error)
993 {
994  return _dbus_is_console_user (uid, error);
995 
996 }
997 
1007 {
1008  return uid == _dbus_geteuid ();
1009 }
1010 
1019 _dbus_windows_user_is_process_owner (const char *windows_sid)
1020 {
1021  return FALSE;
1022 }
1023  /* End of DBusInternalsUtils functions */
1025 
1039  DBusString *dirname)
1040 {
1041  int sep;
1042 
1043  _dbus_assert (filename != dirname);
1044  _dbus_assert (filename != NULL);
1045  _dbus_assert (dirname != NULL);
1046 
1047  /* Ignore any separators on the end */
1048  sep = _dbus_string_get_length (filename);
1049  if (sep == 0)
1050  return _dbus_string_append (dirname, "."); /* empty string passed in */
1051 
1052  while (sep > 0 && _dbus_string_get_byte (filename, sep - 1) == '/')
1053  --sep;
1054 
1055  _dbus_assert (sep >= 0);
1056 
1057  if (sep == 0)
1058  return _dbus_string_append (dirname, "/");
1059 
1060  /* Now find the previous separator */
1061  _dbus_string_find_byte_backward (filename, sep, '/', &sep);
1062  if (sep < 0)
1063  return _dbus_string_append (dirname, ".");
1064 
1065  /* skip multiple separators */
1066  while (sep > 0 && _dbus_string_get_byte (filename, sep - 1) == '/')
1067  --sep;
1068 
1069  _dbus_assert (sep >= 0);
1070 
1071  if (sep == 0 &&
1072  _dbus_string_get_byte (filename, 0) == '/')
1073  return _dbus_string_append (dirname, "/");
1074  else
1075  return _dbus_string_copy_len (filename, 0, sep - 0,
1076  dirname, _dbus_string_get_length (dirname));
1077 } /* DBusString stuff */
1079 
1080 static void
1081 string_squash_nonprintable (DBusString *str)
1082 {
1083  unsigned char *buf;
1084  int i, len;
1085 
1086  buf = _dbus_string_get_udata (str);
1087  len = _dbus_string_get_length (str);
1088 
1089  for (i = 0; i < len; i++)
1090  {
1091  unsigned char c = (unsigned char) buf[i];
1092  if (c == '\0')
1093  buf[i] = ' ';
1094  else if (c < 0x20 || c > 127)
1095  buf[i] = '?';
1096  }
1097 }
1098 
1113 dbus_bool_t
1114 _dbus_command_for_pid (unsigned long pid,
1115  DBusString *str,
1116  int max_len,
1117  DBusError *error)
1118 {
1119  /* This is all Linux-specific for now */
1120  DBusString path;
1121  DBusString cmdline;
1122  int fd;
1123 
1124  if (!_dbus_string_init (&path))
1125  {
1126  _DBUS_SET_OOM (error);
1127  return FALSE;
1128  }
1129 
1130  if (!_dbus_string_init (&cmdline))
1131  {
1132  _DBUS_SET_OOM (error);
1133  _dbus_string_free (&path);
1134  return FALSE;
1135  }
1136 
1137  if (!_dbus_string_append_printf (&path, "/proc/%ld/cmdline", pid))
1138  goto oom;
1139 
1140  fd = open (_dbus_string_get_const_data (&path), O_RDONLY);
1141  if (fd < 0)
1142  {
1143  dbus_set_error (error,
1144  _dbus_error_from_errno (errno),
1145  "Failed to open \"%s\": %s",
1146  _dbus_string_get_const_data (&path),
1147  _dbus_strerror (errno));
1148  goto fail;
1149  }
1150 
1151  if (!_dbus_read (fd, &cmdline, max_len))
1152  {
1153  dbus_set_error (error,
1154  _dbus_error_from_errno (errno),
1155  "Failed to read from \"%s\": %s",
1156  _dbus_string_get_const_data (&path),
1157  _dbus_strerror (errno));
1158  _dbus_close (fd, NULL);
1159  goto fail;
1160  }
1161 
1162  if (!_dbus_close (fd, error))
1163  goto fail;
1164 
1165  string_squash_nonprintable (&cmdline);
1166 
1167  if (!_dbus_string_copy (&cmdline, 0, str, _dbus_string_get_length (str)))
1168  goto oom;
1169 
1170  _dbus_string_free (&cmdline);
1171  _dbus_string_free (&path);
1172  return TRUE;
1173 oom:
1174  _DBUS_SET_OOM (error);
1175 fail:
1176  _dbus_string_free (&cmdline);
1177  _dbus_string_free (&path);
1178  return FALSE;
1179 }
1180 
1191 {
1192  return TRUE;
1193 }
1194 
1195 static dbus_bool_t
1196 ensure_owned_directory (const char *label,
1197  const DBusString *string,
1198  dbus_bool_t create,
1199  DBusError *error)
1200 {
1201  const char *dir = _dbus_string_get_const_data (string);
1202  struct stat buf;
1203 
1204  if (create && !_dbus_ensure_directory (string, error))
1205  return FALSE;
1206 
1207  /*
1208  * The stat()-based checks in this function are to protect against
1209  * mistakes, not malice. We are working in a directory that is meant
1210  * to be trusted; but if a user has used `su` or similar to escalate
1211  * their privileges without correctly clearing the environment, the
1212  * XDG_RUNTIME_DIR in the environment might still be the user's
1213  * and not root's. We don't want to write root-owned files into that
1214  * directory, so just warn and don't provide support for transient
1215  * services in that case.
1216  *
1217  * In particular, we use stat() and not lstat() so that if we later
1218  * decide to use a different directory name for transient services,
1219  * we can drop in a compatibility symlink without breaking older
1220  * libdbus.
1221  */
1222 
1223  if (stat (dir, &buf) != 0)
1224  {
1225  int saved_errno = errno;
1226 
1227  dbus_set_error (error, _dbus_error_from_errno (saved_errno),
1228  "%s \"%s\" not available: %s", label, dir,
1229  _dbus_strerror (saved_errno));
1230  return FALSE;
1231  }
1232 
1233  if (!S_ISDIR (buf.st_mode))
1234  {
1235  dbus_set_error (error, DBUS_ERROR_FAILED, "%s \"%s\" is not a directory",
1236  label, dir);
1237  return FALSE;
1238  }
1239 
1240  if (buf.st_uid != geteuid ())
1241  {
1243  "%s \"%s\" is owned by uid %ld, not our uid %ld",
1244  label, dir, (long) buf.st_uid, (long) geteuid ());
1245  return FALSE;
1246  }
1247 
1248  /* This is just because we have the stat() results already, so we might
1249  * as well check opportunistically. */
1250  if ((S_IWOTH | S_IWGRP) & buf.st_mode)
1251  {
1253  "%s \"%s\" can be written by others (mode 0%o)",
1254  label, dir, buf.st_mode);
1255  return FALSE;
1256  }
1257 
1258  return TRUE;
1259 }
1260 
1261 #define DBUS_UNIX_STANDARD_SESSION_SERVICEDIR "/dbus-1/services"
1262 #define DBUS_UNIX_STANDARD_SYSTEM_SERVICEDIR "/dbus-1/system-services"
1263 
1273  DBusError *error)
1274 {
1275  const char *xdg_runtime_dir;
1276  DBusString services;
1277  DBusString dbus1;
1278  DBusString xrd;
1279  dbus_bool_t ret = FALSE;
1280  char *data = NULL;
1281 
1282  if (!_dbus_string_init (&dbus1))
1283  {
1284  _DBUS_SET_OOM (error);
1285  return FALSE;
1286  }
1287 
1288  if (!_dbus_string_init (&services))
1289  {
1290  _dbus_string_free (&dbus1);
1291  _DBUS_SET_OOM (error);
1292  return FALSE;
1293  }
1294 
1295  if (!_dbus_string_init (&xrd))
1296  {
1297  _dbus_string_free (&dbus1);
1298  _dbus_string_free (&services);
1299  _DBUS_SET_OOM (error);
1300  return FALSE;
1301  }
1302 
1303  xdg_runtime_dir = _dbus_getenv ("XDG_RUNTIME_DIR");
1304 
1305  /* Not an error, we just can't have transient session services */
1306  if (xdg_runtime_dir == NULL)
1307  {
1308  _dbus_verbose ("XDG_RUNTIME_DIR is unset: transient session services "
1309  "not available here\n");
1310  ret = TRUE;
1311  goto out;
1312  }
1313 
1314  if (!_dbus_string_append (&xrd, xdg_runtime_dir) ||
1315  !_dbus_string_append_printf (&dbus1, "%s/dbus-1",
1316  xdg_runtime_dir) ||
1317  !_dbus_string_append_printf (&services, "%s/dbus-1/services",
1318  xdg_runtime_dir))
1319  {
1320  _DBUS_SET_OOM (error);
1321  goto out;
1322  }
1323 
1324  if (!ensure_owned_directory ("XDG_RUNTIME_DIR", &xrd, FALSE, error) ||
1325  !ensure_owned_directory ("XDG_RUNTIME_DIR subdirectory", &dbus1, TRUE,
1326  error) ||
1327  !ensure_owned_directory ("XDG_RUNTIME_DIR subdirectory", &services,
1328  TRUE, error))
1329  goto out;
1330 
1331  if (!_dbus_string_steal_data (&services, &data) ||
1332  !_dbus_list_append (dirs, data))
1333  {
1334  _DBUS_SET_OOM (error);
1335  goto out;
1336  }
1337 
1338  _dbus_verbose ("Transient service directory is %s\n", data);
1339  /* Ownership was transferred to @dirs */
1340  data = NULL;
1341  ret = TRUE;
1342 
1343 out:
1344  _dbus_string_free (&dbus1);
1345  _dbus_string_free (&services);
1346  _dbus_string_free (&xrd);
1347  dbus_free (data);
1348  return ret;
1349 }
1350 
1370 {
1371  const char *xdg_data_home;
1372  const char *xdg_data_dirs;
1373  DBusString servicedir_path;
1374 
1375  if (!_dbus_string_init (&servicedir_path))
1376  return FALSE;
1377 
1378  xdg_data_home = _dbus_getenv ("XDG_DATA_HOME");
1379  xdg_data_dirs = _dbus_getenv ("XDG_DATA_DIRS");
1380 
1381  if (xdg_data_home != NULL)
1382  {
1383  if (!_dbus_string_append (&servicedir_path, xdg_data_home))
1384  goto oom;
1385  }
1386  else
1387  {
1388  const DBusString *homedir;
1389  DBusString local_share;
1390 
1391  if (!_dbus_homedir_from_current_process (&homedir))
1392  goto oom;
1393 
1394  if (!_dbus_string_append (&servicedir_path, _dbus_string_get_const_data (homedir)))
1395  goto oom;
1396 
1397  _dbus_string_init_const (&local_share, "/.local/share");
1398  if (!_dbus_concat_dir_and_file (&servicedir_path, &local_share))
1399  goto oom;
1400  }
1401 
1402  if (!_dbus_string_append (&servicedir_path, ":"))
1403  goto oom;
1404 
1405  if (xdg_data_dirs != NULL)
1406  {
1407  if (!_dbus_string_append (&servicedir_path, xdg_data_dirs))
1408  goto oom;
1409 
1410  if (!_dbus_string_append (&servicedir_path, ":"))
1411  goto oom;
1412  }
1413  else
1414  {
1415  if (!_dbus_string_append (&servicedir_path, "/usr/local/share:/usr/share:"))
1416  goto oom;
1417  }
1418 
1419  /*
1420  * add configured datadir to defaults
1421  * this may be the same as an xdg dir
1422  * however the config parser should take
1423  * care of duplicates
1424  */
1425  if (!_dbus_string_append (&servicedir_path, DBUS_DATADIR))
1426  goto oom;
1427 
1428  if (!_dbus_split_paths_and_append (&servicedir_path,
1429  DBUS_UNIX_STANDARD_SESSION_SERVICEDIR,
1430  dirs))
1431  goto oom;
1432 
1433  _dbus_string_free (&servicedir_path);
1434  return TRUE;
1435 
1436  oom:
1437  _dbus_string_free (&servicedir_path);
1438  return FALSE;
1439 }
1440 
1441 
1462 {
1463  /*
1464  * DBUS_DATADIR may be the same as one of the standard directories. However,
1465  * the config parser should take care of the duplicates.
1466  *
1467  * Also, append /lib as counterpart of /usr/share on the root
1468  * directory (the root directory does not know /share), in order to
1469  * facilitate early boot system bus activation where /usr might not
1470  * be available.
1471  */
1472  static const char standard_search_path[] =
1473  "/usr/local/share:"
1474  "/usr/share:"
1475  DBUS_DATADIR ":"
1476  "/lib";
1477  DBusString servicedir_path;
1478 
1479  _dbus_string_init_const (&servicedir_path, standard_search_path);
1480 
1481  return _dbus_split_paths_and_append (&servicedir_path,
1482  DBUS_UNIX_STANDARD_SYSTEM_SERVICEDIR,
1483  dirs);
1484 }
1485 
1496 {
1497  _dbus_assert (_dbus_string_get_length (str) == 0);
1498 
1499  return _dbus_string_append (str, DBUS_SYSTEM_CONFIG_FILE);
1500 }
1501 
1510 {
1511  _dbus_assert (_dbus_string_get_length (str) == 0);
1512 
1513  return _dbus_string_append (str, DBUS_SESSION_CONFIG_FILE);
1514 }
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:935
dbus_bool_t _dbus_split_paths_and_append(DBusString *dirs, const char *suffix, DBusList **dir_list)
Split paths into a list of char strings.
Definition: dbus-sysdeps.c:228
const char * message
public error message field
Definition: dbus-errors.h:51
#define NULL
A null pointer, defined appropriately for C or C++.
dbus_bool_t _dbus_become_daemon(const DBusString *pidfile, DBusPipe *print_pid_pipe, DBusError *error, dbus_bool_t keep_umask)
Does the chdir, fork, setsid, etc.
dbus_bool_t _dbus_unix_user_is_at_console(dbus_uid_t uid, DBusError *error)
Checks to see if the UNIX user ID is at the console.
dbus_bool_t _dbus_group_info_fill_gid(DBusGroupInfo *info, dbus_gid_t gid, DBusError *error)
Initializes the given DBusGroupInfo struct with information about the given group ID...
dbus_bool_t _dbus_string_get_dirname(const DBusString *filename, DBusString *dirname)
Get the directory name from a complete filename.
dbus_bool_t _dbus_ensure_directory(const DBusString *filename, DBusError *error)
Creates a directory; succeeds if the directory is created or already existed.
void dbus_free(void *memory)
Frees a block of memory previously allocated by dbus_malloc() or dbus_malloc0().
Definition: dbus-memory.c:702
dbus_bool_t _dbus_path_is_absolute(const DBusString *filename)
Checks whether the filename is an absolute path.
Portable struct with stat() results.
Definition: dbus-sysdeps.h:501
dbus_bool_t _dbus_ensure_standard_fds(DBusEnsureStandardFdsFlags flags, const char **error_str_p)
Ensure that the standard file descriptors stdin, stdout and stderr are open, by opening /dev/null if ...
#define DBUS_ERROR_NOT_SUPPORTED
Requested operation isn&#39;t supported (like ENOSYS on UNIX).
DBUS_PRIVATE_EXPORT dbus_bool_t _dbus_string_append_int(DBusString *str, long value)
Appends an integer to a DBusString.
Definition: dbus-sysdeps.c:356
dbus_bool_t _dbus_groups_from_uid(dbus_uid_t uid, dbus_gid_t **group_ids, int *n_group_ids)
Gets all groups corresponding to the given UID.
dbus_bool_t _dbus_parse_unix_group_from_config(const DBusString *groupname, dbus_gid_t *gid_p)
Parse a UNIX group from the bus config file.
void _dbus_directory_close(DBusDirIter *iter)
Closes a directory iteration.
dbus_bool_t _dbus_is_console_user(dbus_uid_t uid, DBusError *error)
Checks to see if the UID sent in is the console user.
#define _dbus_assert(condition)
Aborts with an error message if the condition is false.
dbus_bool_t _dbus_directory_get_next_file(DBusDirIter *iter, DBusString *filename, DBusError *error)
Get next file in the directory.
unsigned long atime
Access time.
Definition: dbus-sysdeps.h:508
dbus_bool_t _dbus_get_standard_session_servicedirs(DBusList **dirs)
Returns the standard directories for a session bus to look for service activation files...
dbus_bool_t _dbus_concat_dir_and_file(DBusString *dir, const DBusString *next_component)
Appends the given filename to the given directory.
DBusDirIter * _dbus_directory_open(const DBusString *filename, DBusError *error)
Open a directory to iterate over.
dbus_bool_t _dbus_string_init(DBusString *str)
Initializes a string.
Definition: dbus-string.c:175
dbus_bool_t _dbus_command_for_pid(unsigned long pid, DBusString *str, int max_len, DBusError *error)
Get a printable string describing the command used to execute the process with pid.
dbus_bool_t _dbus_get_system_config_file(DBusString *str)
Get the absolute path of the system.conf file (there is no system bus on Windows so this can just ret...
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:1283
char * groupname
Group name.
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:592
Internals of directory iterator.
unsigned long mode
File mode.
Definition: dbus-sysdeps.h:503
unsigned long dbus_pid_t
A process ID.
Definition: dbus-sysdeps.h:106
dbus_bool_t _dbus_get_user_id_and_primary_group(const DBusString *username, dbus_uid_t *uid_p, dbus_gid_t *gid_p)
Gets user ID and primary group given username.
dbus_bool_t _dbus_change_to_daemon_user(const char *user, DBusError *error)
Changes the user and group the bus is running as.
DIR * d
The DIR* from opendir()
void * dbus_malloc(size_t bytes)
Allocates the given number of bytes, as with standard malloc().
Definition: dbus-memory.c:462
dbus_gid_t gid
Group owning file.
Definition: dbus-sysdeps.h:506
#define dbus_new0(type, count)
Safe macro for using dbus_malloc0().
Definition: dbus-memory.h:59
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:35
void _dbus_string_init_const(DBusString *str, const char *value)
Initializes a constant string.
Definition: dbus-string.c:190
dbus_bool_t _dbus_get_session_config_file(DBusString *str)
Get the absolute path of the session.conf file.
void _dbus_warn(const char *format,...)
Prints a warning message to stderr.
dbus_bool_t _dbus_list_append(DBusList **list, void *data)
Appends a value to the list.
Definition: dbus-list.c:270
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...
dbus_bool_t _dbus_string_append_printf(DBusString *str, const char *format,...)
Appends a printf-style formatted string to the DBusString.
Definition: dbus-string.c:1114
dbus_bool_t _dbus_group_info_fill(DBusGroupInfo *info, const DBusString *groupname, DBusError *error)
Initializes the given DBusGroupInfo struct with information about the given group name...
dbus_bool_t _dbus_get_group_id(const DBusString *groupname, dbus_gid_t *gid)
Gets group ID given groupname.
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
dbus_bool_t _dbus_unix_groups_from_uid(dbus_uid_t uid, dbus_gid_t **group_ids, int *n_group_ids)
Gets all groups corresponding to the given UNIX user ID.
unsigned long ctime
Creation time.
Definition: dbus-sysdeps.h:510
void _dbus_string_free(DBusString *str)
Frees a string created by _dbus_string_init().
Definition: dbus-string.c:259
#define DBUS_GID_UNSET
an invalid GID used to represent an uninitialized dbus_gid_t field
Definition: dbus-sysdeps.h:117
dbus_uid_t _dbus_geteuid(void)
Gets our effective UID.
dbus_bool_t _dbus_file_exists(const char *file)
Checks if a file exists.
#define TRUE
Expands to "1".
unsigned long nlink
Number of hard links.
Definition: dbus-sysdeps.h:504
#define _dbus_assert_not_reached(explanation)
Aborts with an error message if called.
dbus_bool_t _dbus_write_pid_to_file_and_pipe(const DBusString *pidfile, DBusPipe *print_pid_pipe, dbus_pid_t pid_to_write, DBusError *error)
Writes the given pid_to_write to a pidfile (if non-NULL) and/or to a pipe (if non-NULL).
dbus_uid_t uid
User owning file.
Definition: dbus-sysdeps.h:505
#define DBUS_ERROR_FAILED
A generic error; "something went wrong" - see the error message for more.
dbus_bool_t _dbus_verify_daemon_user(const char *user)
Verify that after the fork we can successfully change to this user.
dbus_bool_t _dbus_string_find_byte_backward(const DBusString *str, int start, unsigned char byte, int *found)
Find the given byte scanning backward from the given start.
dbus_bool_t _dbus_homedir_from_current_process(const DBusString **homedir)
Gets homedir of user owning current process.
Definition: dbus-userdb.c:395
Information about a UNIX group.
dbus_bool_t _dbus_stat(const DBusString *filename, DBusStat *statbuf, DBusError *error)
stat() wrapper.
dbus_bool_t _dbus_get_user_id(const DBusString *username, dbus_uid_t *uid)
Gets user ID given username.
void _dbus_set_signal_handler(int sig, DBusSignalHandler handler)
Installs a UNIX signal handler.
A node in a linked list.
Definition: dbus-list.h:34
dbus_bool_t _dbus_unix_user_is_process_owner(dbus_uid_t uid)
Checks to see if the UNIX user ID matches the UID of the process.
dbus_bool_t _dbus_replace_install_prefix(DBusString *path)
Replace the DBUS_PREFIX in the given path, in-place, by the current D-Bus installation directory...
dbus_bool_t _dbus_user_at_console(const char *username, DBusError *error)
Checks if user is at the console.
dbus_bool_t _dbus_windows_user_is_process_owner(const char *windows_sid)
Checks to see if the Windows user SID matches the owner of the process.
dbus_bool_t _dbus_set_up_transient_session_servicedirs(DBusList **dirs, DBusError *error)
Returns the standard directories for a session bus to look for transient service activation files...
#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".
unsigned long mtime
Modify time.
Definition: dbus-sysdeps.h:509
dbus_bool_t _dbus_string_set_length(DBusString *str, int length)
Sets the length of a string.
Definition: dbus-string.c:802
dbus_bool_t _dbus_string_copy_len(const DBusString *source, int start, int len, DBusString *dest, int insert_at)
Like _dbus_string_copy(), but can copy a segment from the middle of the source string.
Definition: dbus-string.c:1375
dbus_bool_t _dbus_string_steal_data(DBusString *str, char **data_return)
Like _dbus_string_get_data(), but removes the gotten data from the original string.
Definition: dbus-string.c:641
dbus_gid_t gid
GID.
void(* DBusSignalHandler)(int sig)
A UNIX signal handler.
unsigned long dbus_gid_t
A group ID.
Definition: dbus-sysdeps.h:110
unsigned long size
Size of file.
Definition: dbus-sysdeps.h:507
dbus_bool_t _dbus_parse_unix_user_from_config(const DBusString *username, dbus_uid_t *uid_p)
Parse a UNIX user from the bus config file.
char * _dbus_strdup(const char *str)
Duplicates a string.
const char * _dbus_getenv(const char *varname)
Wrapper for getenv().
Definition: dbus-sysdeps.c:187
unsigned long dbus_uid_t
A user ID.
Definition: dbus-sysdeps.h:108
dbus_bool_t _dbus_get_standard_system_servicedirs(DBusList **dirs)
Returns the standard directories for a system bus to look for service activation files.
dbus_bool_t dbus_error_is_set(const DBusError *error)
Checks whether an error occurred (the error is set).
Definition: dbus-errors.c:329