1 /* -*- mode: C; c-file-style: "gnu" -*- */
2 /* dbus-sysdeps-util-unix.c Would be in dbus-sysdeps-unix.c, but not used in libdbus
4 * Copyright (C) 2002, 2003, 2004, 2005 Red Hat, Inc.
5 * Copyright (C) 2003 CodeFactory AB
7 * Licensed under the Academic Free License version 2.1
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.
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.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include "dbus-sysdeps.h"
25 #include "dbus-sysdeps-unix.h"
26 #include "dbus-internals.h"
27 #include "dbus-protocol.h"
28 #include "dbus-string.h"
29 #define DBUS_USERDB_INCLUDES_PRIVATE 1
30 #include "dbus-userdb.h"
31 #include "dbus-test.h"
33 #include <sys/types.h>
43 #include <sys/socket.h>
47 #ifdef HAVE_SYS_SYSLIMITS_H
48 #include <sys/syslimits.h>
56 * @addtogroup DBusInternalsUtils
61 * Does the chdir, fork, setsid, etc. to become a daemon process.
63 * @param pidfile #NULL, or pidfile to create
64 * @param print_pid_fd file descriptor to print daemon's pid to, or -1 for none
65 * @param error return location for errors
66 * @returns #FALSE on failure
69 _dbus_become_daemon (const DBusString *pidfile,
70 DBusPipe print_pid_fd,
77 _dbus_verbose ("Becoming a daemon...\n");
79 _dbus_verbose ("chdir to /\n");
82 dbus_set_error (error, DBUS_ERROR_FAILED,
83 "Could not chdir() to root directory");
87 _dbus_verbose ("forking...\n");
88 switch ((child_pid = fork ()))
91 _dbus_verbose ("fork failed\n");
92 dbus_set_error (error, _dbus_error_from_errno (errno),
93 "Failed to fork daemon: %s", _dbus_strerror (errno));
98 _dbus_verbose ("in child, closing std file descriptors\n");
100 /* silently ignore failures here, if someone
101 * doesn't have /dev/null we may as well try
105 dev_null_fd = open ("/dev/null", O_RDWR);
106 if (dev_null_fd >= 0)
108 dup2 (dev_null_fd, 0);
109 dup2 (dev_null_fd, 1);
111 s = _dbus_getenv ("DBUS_DEBUG_OUTPUT");
112 if (s == NULL || *s == '\0')
113 dup2 (dev_null_fd, 2);
115 _dbus_verbose ("keeping stderr open due to DBUS_DEBUG_OUTPUT\n");
118 /* Get a predictable umask */
119 _dbus_verbose ("setting umask\n");
126 _dbus_verbose ("parent writing pid file\n");
127 if (!_dbus_write_pid_file (pidfile,
131 _dbus_verbose ("pid file write failed, killing child\n");
132 kill (child_pid, SIGTERM);
137 /* Write PID if requested */
138 if (_dbus_pipe_is_valid(print_pid_fd))
143 if (!_dbus_string_init (&pid))
145 _DBUS_SET_OOM (error);
146 kill (child_pid, SIGTERM);
150 if (!_dbus_string_append_int (&pid, child_pid) ||
151 !_dbus_string_append (&pid, "\n"))
153 _dbus_string_free (&pid);
154 _DBUS_SET_OOM (error);
155 kill (child_pid, SIGTERM);
159 bytes = _dbus_string_get_length (&pid);
160 if (_dbus_pipe_write (print_pid_fd, &pid, 0, bytes) != bytes)
162 dbus_set_error (error, DBUS_ERROR_FAILED,
163 "Printing message bus PID: %s\n",
164 _dbus_strerror (errno));
165 _dbus_string_free (&pid);
166 kill (child_pid, SIGTERM);
170 _dbus_string_free (&pid);
172 _dbus_verbose ("parent exiting\n");
177 _dbus_verbose ("calling setsid()\n");
179 _dbus_assert_not_reached ("setsid() failed");
186 * Creates a file containing the process ID.
188 * @param filename the filename to write to
189 * @param pid our process ID
190 * @param error return location for errors
191 * @returns #FALSE on failure
194 _dbus_write_pid_file (const DBusString *filename,
198 const char *cfilename;
202 cfilename = _dbus_string_get_const_data (filename);
204 fd = open (cfilename, O_WRONLY|O_CREAT|O_EXCL|O_BINARY, 0644);
208 dbus_set_error (error, _dbus_error_from_errno (errno),
209 "Failed to open \"%s\": %s", cfilename,
210 _dbus_strerror (errno));
214 if ((f = fdopen (fd, "w")) == NULL)
216 dbus_set_error (error, _dbus_error_from_errno (errno),
217 "Failed to fdopen fd %d: %s", fd, _dbus_strerror (errno));
218 _dbus_close (fd, NULL);
222 if (fprintf (f, "%lu\n", pid) < 0)
224 dbus_set_error (error, _dbus_error_from_errno (errno),
225 "Failed to write to \"%s\": %s", cfilename,
226 _dbus_strerror (errno));
232 if (fclose (f) == EOF)
234 dbus_set_error (error, _dbus_error_from_errno (errno),
235 "Failed to close \"%s\": %s", cfilename,
236 _dbus_strerror (errno));
245 * Changes the user and group the bus is running as.
247 * @param uid the new user ID
248 * @param gid the new group ID
249 * @param error return location for errors
250 * @returns #FALSE on failure
253 _dbus_change_identity (dbus_uid_t uid,
257 /* setgroups() only works if we are a privileged process,
258 * so we don't return error on failure; the only possible
259 * failure is that we don't have perms to do it.
261 * not sure this is right, maybe if setuid()
262 * is going to work then setgroups() should also work.
264 if (setgroups (0, NULL) < 0)
265 _dbus_warn ("Failed to drop supplementary groups: %s\n",
266 _dbus_strerror (errno));
268 /* Set GID first, or the setuid may remove our permission
271 if (setgid (gid) < 0)
273 dbus_set_error (error, _dbus_error_from_errno (errno),
274 "Failed to set GID to %lu: %s", gid,
275 _dbus_strerror (errno));
279 if (setuid (uid) < 0)
281 dbus_set_error (error, _dbus_error_from_errno (errno),
282 "Failed to set UID to %lu: %s", uid,
283 _dbus_strerror (errno));
290 /** Installs a UNIX signal handler
292 * @param sig the signal to handle
293 * @param handler the handler
296 _dbus_set_signal_handler (int sig,
297 DBusSignalHandler handler)
299 struct sigaction act;
302 sigemptyset (&empty_mask);
303 act.sa_handler = handler;
304 act.sa_mask = empty_mask;
306 sigaction (sig, &act, NULL);
311 * Removes a directory; Directory must be empty
313 * @param filename directory filename
314 * @param error initialized error object
315 * @returns #TRUE on success
318 _dbus_delete_directory (const DBusString *filename,
321 const char *filename_c;
323 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
325 filename_c = _dbus_string_get_const_data (filename);
327 if (rmdir (filename_c) != 0)
329 dbus_set_error (error, DBUS_ERROR_FAILED,
330 "Failed to remove directory %s: %s\n",
331 filename_c, _dbus_strerror (errno));
338 /** Checks if a file exists
340 * @param file full path to the file
341 * @returns #TRUE if file exists
344 _dbus_file_exists (const char *file)
346 return (access (file, F_OK) == 0);
349 /** Checks if user is at the console
351 * @param username user to check
352 * @param error return location for errors
353 * @returns #TRUE is the user is at the consolei and there are no errors
356 _dbus_user_at_console (const char *username,
364 if (!_dbus_string_init (&f))
366 _DBUS_SET_OOM (error);
370 if (!_dbus_string_append (&f, DBUS_CONSOLE_AUTH_DIR))
372 _DBUS_SET_OOM (error);
377 if (!_dbus_string_append (&f, username))
379 _DBUS_SET_OOM (error);
383 result = _dbus_file_exists (_dbus_string_get_const_data (&f));
386 _dbus_string_free (&f);
393 * Checks whether the filename is an absolute path
395 * @param filename the filename
396 * @returns #TRUE if an absolute path
399 _dbus_path_is_absolute (const DBusString *filename)
401 if (_dbus_string_get_length (filename) > 0)
402 return _dbus_string_get_byte (filename, 0) == '/';
410 * @param filename the filename to stat
411 * @param statbuf the stat info to fill in
412 * @param error return location for error
413 * @returns #FALSE if error was set
416 _dbus_stat (const DBusString *filename,
420 const char *filename_c;
423 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
425 filename_c = _dbus_string_get_const_data (filename);
427 if (stat (filename_c, &sb) < 0)
429 dbus_set_error (error, _dbus_error_from_errno (errno),
430 "%s", _dbus_strerror (errno));
434 statbuf->mode = sb.st_mode;
435 statbuf->nlink = sb.st_nlink;
436 statbuf->uid = sb.st_uid;
437 statbuf->gid = sb.st_gid;
438 statbuf->size = sb.st_size;
439 statbuf->atime = sb.st_atime;
440 statbuf->mtime = sb.st_mtime;
441 statbuf->ctime = sb.st_ctime;
448 * Internals of directory iterator
452 DIR *d; /**< The DIR* from opendir() */
457 * Open a directory to iterate over.
459 * @param filename the directory name
460 * @param error exception return object or #NULL
461 * @returns new iterator, or #NULL on error
464 _dbus_directory_open (const DBusString *filename,
469 const char *filename_c;
471 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
473 filename_c = _dbus_string_get_const_data (filename);
475 d = opendir (filename_c);
478 dbus_set_error (error, _dbus_error_from_errno (errno),
479 "Failed to read directory \"%s\": %s",
481 _dbus_strerror (errno));
484 iter = dbus_new0 (DBusDirIter, 1);
488 dbus_set_error (error, DBUS_ERROR_NO_MEMORY,
489 "Could not allocate memory for directory iterator");
498 /* Calculate the required buffer size (in bytes) for directory
499 * entries read from the given directory handle. Return -1 if this
500 * this cannot be done.
502 * If you use autoconf, include fpathconf and dirfd in your
503 * AC_CHECK_FUNCS list. Otherwise use some other method to detect
504 * and use them where available.
507 dirent_buf_size(DIR * dirp, size_t *size)
510 # if defined(HAVE_FPATHCONF) && defined(_PC_NAME_MAX)
511 # if defined(HAVE_DIRFD)
512 name_max = fpathconf(dirfd(dirp), _PC_NAME_MAX);
513 # elif defined(HAVE_DDFD)
514 name_max = fpathconf(dirp->dd_fd, _PC_NAME_MAX);
516 name_max = fpathconf(dirp->__dd_fd, _PC_NAME_MAX);
517 # endif /* HAVE_DIRFD */
519 # if defined(NAME_MAX)
524 # elif defined(MAXNAMELEN)
525 name_max = MAXNAMELEN;
527 # if defined(NAME_MAX)
530 # error "buffer size for readdir_r cannot be determined"
534 *size = (size_t)offsetof(struct dirent, d_name) + name_max + 1;
542 * Get next file in the directory. Will not return "." or ".." on
543 * UNIX. If an error occurs, the contents of "filename" are
544 * undefined. The error is never set if the function succeeds.
546 * @param iter the iterator
547 * @param filename string to be set to the next file in the dir
548 * @param error return location for error
549 * @returns #TRUE if filename was filled in with a new filename
552 _dbus_directory_get_next_file (DBusDirIter *iter,
553 DBusString *filename,
556 struct dirent *d, *ent;
560 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
562 if (!dirent_buf_size (iter->d, &buf_size))
564 dbus_set_error (error, DBUS_ERROR_FAILED,
565 "Can't calculate buffer size when reading directory");
569 d = (struct dirent *)dbus_malloc (buf_size);
572 dbus_set_error (error, DBUS_ERROR_NO_MEMORY,
573 "No memory to read directory entry");
578 err = readdir_r (iter->d, d, &ent);
582 dbus_set_error (error,
583 _dbus_error_from_errno (err),
584 "%s", _dbus_strerror (err));
589 else if (ent->d_name[0] == '.' &&
590 (ent->d_name[1] == '\0' ||
591 (ent->d_name[1] == '.' && ent->d_name[2] == '\0')))
595 _dbus_string_set_length (filename, 0);
596 if (!_dbus_string_append (filename, ent->d_name))
598 dbus_set_error (error, DBUS_ERROR_NO_MEMORY,
599 "No memory to read directory entry");
612 * Closes a directory iteration.
615 _dbus_directory_close (DBusDirIter *iter)
622 fill_user_info_from_group (struct group *g,
626 _dbus_assert (g->gr_name != NULL);
628 info->gid = g->gr_gid;
629 info->groupname = _dbus_strdup (g->gr_name);
631 /* info->members = dbus_strdupv (g->gr_mem) */
633 if (info->groupname == NULL)
635 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
643 fill_group_info (DBusGroupInfo *info,
645 const DBusString *groupname,
648 const char *group_c_str;
650 _dbus_assert (groupname != NULL || gid != DBUS_GID_UNSET);
651 _dbus_assert (groupname == NULL || gid == DBUS_GID_UNSET);
654 group_c_str = _dbus_string_get_const_data (groupname);
658 /* For now assuming that the getgrnam() and getgrgid() flavors
659 * always correspond to the pwnam flavors, if not we have
660 * to add more configure checks.
663 #if defined (HAVE_POSIX_GETPWNAM_R) || defined (HAVE_NONPOSIX_GETPWNAM_R)
671 #ifdef HAVE_POSIX_GETPWNAM_R
674 result = getgrnam_r (group_c_str, &g_str, buf, sizeof (buf),
677 result = getgrgid_r (gid, &g_str, buf, sizeof (buf),
680 g = getgrnam_r (group_c_str, &g_str, buf, sizeof (buf));
682 #endif /* !HAVE_POSIX_GETPWNAM_R */
683 if (result == 0 && g == &g_str)
685 return fill_user_info_from_group (g, info, error);
689 dbus_set_error (error, _dbus_error_from_errno (errno),
690 "Group %s unknown or failed to look it up\n",
691 group_c_str ? group_c_str : "???");
695 #else /* ! HAVE_GETPWNAM_R */
697 /* I guess we're screwed on thread safety here */
700 g = getgrnam (group_c_str);
704 return fill_user_info_from_group (g, info, error);
708 dbus_set_error (error, _dbus_error_from_errno (errno),
709 "Group %s unknown or failed to look it up\n",
710 group_c_str ? group_c_str : "???");
714 #endif /* ! HAVE_GETPWNAM_R */
718 * Initializes the given DBusGroupInfo struct
719 * with information about the given group name.
721 * @param info the group info struct
722 * @param groupname name of group
723 * @param error the error return
724 * @returns #FALSE if error is set
727 _dbus_group_info_fill (DBusGroupInfo *info,
728 const DBusString *groupname,
731 return fill_group_info (info, DBUS_GID_UNSET,
737 * Initializes the given DBusGroupInfo struct
738 * with information about the given group ID.
740 * @param info the group info struct
741 * @param gid group ID
742 * @param error the error return
743 * @returns #FALSE if error is set
746 _dbus_group_info_fill_gid (DBusGroupInfo *info,
750 return fill_group_info (info, gid, NULL, error);
753 /** @} */ /* End of DBusInternalsUtils functions */
756 * @addtogroup DBusString
761 * Get the directory name from a complete filename
762 * @param filename the filename
763 * @param dirname string to append directory name to
764 * @returns #FALSE if no memory
767 _dbus_string_get_dirname (const DBusString *filename,
772 _dbus_assert (filename != dirname);
773 _dbus_assert (filename != NULL);
774 _dbus_assert (dirname != NULL);
776 /* Ignore any separators on the end */
777 sep = _dbus_string_get_length (filename);
779 return _dbus_string_append (dirname, "."); /* empty string passed in */
781 while (sep > 0 && _dbus_string_get_byte (filename, sep - 1) == '/')
784 _dbus_assert (sep >= 0);
787 return _dbus_string_append (dirname, "/");
789 /* Now find the previous separator */
790 _dbus_string_find_byte_backward (filename, sep, '/', &sep);
792 return _dbus_string_append (dirname, ".");
794 /* skip multiple separators */
795 while (sep > 0 && _dbus_string_get_byte (filename, sep - 1) == '/')
798 _dbus_assert (sep >= 0);
801 _dbus_string_get_byte (filename, 0) == '/')
802 return _dbus_string_append (dirname, "/");
804 return _dbus_string_copy_len (filename, 0, sep - 0,
805 dirname, _dbus_string_get_length (dirname));
807 /** @} */ /* DBusString stuff */