/* -*- mode: C; c-file-style: "gnu" -*- */ /* dbus-sysdeps-util-unix.c Would be in dbus-sysdeps-unix.c, but not used in libdbus * * Copyright (C) 2002, 2003, 2004, 2005 Red Hat, Inc. * Copyright (C) 2003 CodeFactory AB * * Licensed under the Academic Free License version 2.1 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include "dbus-sysdeps.h" #include "dbus-sysdeps-unix.h" #include "dbus-internals.h" #include "dbus-protocol.h" #include "dbus-string.h" #define DBUS_USERDB_INCLUDES_PRIVATE 1 #include "dbus-userdb.h" #include "dbus-test.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef HAVE_SYS_SYSLIMITS_H #include #endif #ifndef O_BINARY #define O_BINARY 0 #endif /** * @addtogroup DBusInternalsUtils * @{ */ /** * Does the chdir, fork, setsid, etc. to become a daemon process. * * @param pidfile #NULL, or pidfile to create * @param print_pid_fd file descriptor to print daemon's pid to, or -1 for none * @param error return location for errors * @returns #FALSE on failure */ dbus_bool_t _dbus_become_daemon (const DBusString *pidfile, int print_pid_fd, DBusError *error) { const char *s; pid_t child_pid; int dev_null_fd; _dbus_verbose ("Becoming a daemon...\n"); _dbus_verbose ("chdir to /\n"); if (chdir ("/") < 0) { dbus_set_error (error, DBUS_ERROR_FAILED, "Could not chdir() to root directory"); return FALSE; } _dbus_verbose ("forking...\n"); switch ((child_pid = fork ())) { case -1: _dbus_verbose ("fork failed\n"); dbus_set_error (error, _dbus_error_from_errno (errno), "Failed to fork daemon: %s", _dbus_strerror (errno)); return FALSE; break; case 0: _dbus_verbose ("in child, closing std file descriptors\n"); /* silently ignore failures here, if someone * doesn't have /dev/null we may as well try * to continue anyhow */ dev_null_fd = open ("/dev/null", O_RDWR); if (dev_null_fd >= 0) { dup2 (dev_null_fd, 0); dup2 (dev_null_fd, 1); s = _dbus_getenv ("DBUS_DEBUG_OUTPUT"); if (s == NULL || *s == '\0') dup2 (dev_null_fd, 2); else _dbus_verbose ("keeping stderr open due to DBUS_DEBUG_OUTPUT\n"); } /* Get a predictable umask */ _dbus_verbose ("setting umask\n"); umask (022); break; default: if (pidfile) { _dbus_verbose ("parent writing pid file\n"); if (!_dbus_write_pid_file (pidfile, child_pid, error)) { _dbus_verbose ("pid file write failed, killing child\n"); kill (child_pid, SIGTERM); return FALSE; } } /* Write PID if requested */ if (print_pid_fd >= 0) { DBusString pid; int bytes; if (!_dbus_string_init (&pid)) { _DBUS_SET_OOM (error); kill (child_pid, SIGTERM); return FALSE; } if (!_dbus_string_append_int (&pid, child_pid) || !_dbus_string_append (&pid, "\n")) { _dbus_string_free (&pid); _DBUS_SET_OOM (error); kill (child_pid, SIGTERM); return FALSE; } bytes = _dbus_string_get_length (&pid); if (_dbus_write_socket (print_pid_fd, &pid, 0, bytes) != bytes) { dbus_set_error (error, DBUS_ERROR_FAILED, "Printing message bus PID: %s\n", _dbus_strerror (errno)); _dbus_string_free (&pid); kill (child_pid, SIGTERM); return FALSE; } _dbus_string_free (&pid); } _dbus_verbose ("parent exiting\n"); _exit (0); break; } _dbus_verbose ("calling setsid()\n"); if (setsid () == -1) _dbus_assert_not_reached ("setsid() failed"); return TRUE; } /** * Creates a file containing the process ID. * * @param filename the filename to write to * @param pid our process ID * @param error return location for errors * @returns #FALSE on failure */ dbus_bool_t _dbus_write_pid_file (const DBusString *filename, unsigned long pid, DBusError *error) { const char *cfilename; int fd; FILE *f; cfilename = _dbus_string_get_const_data (filename); fd = open (cfilename, O_WRONLY|O_CREAT|O_EXCL|O_BINARY, 0644); if (fd < 0) { dbus_set_error (error, _dbus_error_from_errno (errno), "Failed to open \"%s\": %s", cfilename, _dbus_strerror (errno)); return FALSE; } if ((f = fdopen (fd, "w")) == NULL) { dbus_set_error (error, _dbus_error_from_errno (errno), "Failed to fdopen fd %d: %s", fd, _dbus_strerror (errno)); _dbus_close (fd, NULL); return FALSE; } if (fprintf (f, "%lu\n", pid) < 0) { dbus_set_error (error, _dbus_error_from_errno (errno), "Failed to write to \"%s\": %s", cfilename, _dbus_strerror (errno)); fclose (f); return FALSE; } if (fclose (f) == EOF) { dbus_set_error (error, _dbus_error_from_errno (errno), "Failed to close \"%s\": %s", cfilename, _dbus_strerror (errno)); return FALSE; } return TRUE; } /** * Changes the user and group the bus is running as. * * @param uid the new user ID * @param gid the new group ID * @param error return location for errors * @returns #FALSE on failure */ dbus_bool_t _dbus_change_identity (dbus_uid_t uid, dbus_gid_t gid, DBusError *error) { /* setgroups() only works if we are a privileged process, * so we don't return error on failure; the only possible * failure is that we don't have perms to do it. * * not sure this is right, maybe if setuid() * is going to work then setgroups() should also work. */ if (setgroups (0, NULL) < 0) _dbus_warn ("Failed to drop supplementary groups: %s\n", _dbus_strerror (errno)); /* Set GID first, or the setuid may remove our permission * to change the GID */ if (setgid (gid) < 0) { dbus_set_error (error, _dbus_error_from_errno (errno), "Failed to set GID to %lu: %s", gid, _dbus_strerror (errno)); return FALSE; } if (setuid (uid) < 0) { dbus_set_error (error, _dbus_error_from_errno (errno), "Failed to set UID to %lu: %s", uid, _dbus_strerror (errno)); return FALSE; } return TRUE; } /** Installs a UNIX signal handler * * @param sig the signal to handle * @param handler the handler */ void _dbus_set_signal_handler (int sig, DBusSignalHandler handler) { struct sigaction act; sigset_t empty_mask; sigemptyset (&empty_mask); act.sa_handler = handler; act.sa_mask = empty_mask; act.sa_flags = 0; sigaction (sig, &act, NULL); } /** * Removes a directory; Directory must be empty * * @param filename directory filename * @param error initialized error object * @returns #TRUE on success */ dbus_bool_t _dbus_delete_directory (const DBusString *filename, DBusError *error) { const char *filename_c; _DBUS_ASSERT_ERROR_IS_CLEAR (error); filename_c = _dbus_string_get_const_data (filename); if (rmdir (filename_c) != 0) { dbus_set_error (error, DBUS_ERROR_FAILED, "Failed to remove directory %s: %s\n", filename_c, _dbus_strerror (errno)); return FALSE; } return TRUE; } /** Checks if a file exists * * @param file full path to the file * @returns #TRUE if file exists */ dbus_bool_t _dbus_file_exists (const char *file) { return (access (file, F_OK) == 0); } /** Checks if user is at the console * * @param username user to check * @param error return location for errors * @returns #TRUE is the user is at the consolei and there are no errors */ dbus_bool_t _dbus_user_at_console (const char *username, DBusError *error) { DBusString f; dbus_bool_t result; result = FALSE; if (!_dbus_string_init (&f)) { _DBUS_SET_OOM (error); return FALSE; } if (!_dbus_string_append (&f, DBUS_CONSOLE_AUTH_DIR)) { _DBUS_SET_OOM (error); goto out; } if (!_dbus_string_append (&f, username)) { _DBUS_SET_OOM (error); goto out; } result = _dbus_file_exists (_dbus_string_get_const_data (&f)); out: _dbus_string_free (&f); return result; } /** * Checks whether the filename is an absolute path * * @param filename the filename * @returns #TRUE if an absolute path */ dbus_bool_t _dbus_path_is_absolute (const DBusString *filename) { if (_dbus_string_get_length (filename) > 0) return _dbus_string_get_byte (filename, 0) == '/'; else return FALSE; } /** * stat() wrapper. * * @param filename the filename to stat * @param statbuf the stat info to fill in * @param error return location for error * @returns #FALSE if error was set */ dbus_bool_t _dbus_stat (const DBusString *filename, DBusStat *statbuf, DBusError *error) { const char *filename_c; struct stat sb; _DBUS_ASSERT_ERROR_IS_CLEAR (error); filename_c = _dbus_string_get_const_data (filename); if (stat (filename_c, &sb) < 0) { dbus_set_error (error, _dbus_error_from_errno (errno), "%s", _dbus_strerror (errno)); return FALSE; } statbuf->mode = sb.st_mode; statbuf->nlink = sb.st_nlink; statbuf->uid = sb.st_uid; statbuf->gid = sb.st_gid; statbuf->size = sb.st_size; statbuf->atime = sb.st_atime; statbuf->mtime = sb.st_mtime; statbuf->ctime = sb.st_ctime; return TRUE; } /** * Internals of directory iterator */ struct DBusDirIter { DIR *d; /**< The DIR* from opendir() */ }; /** * Open a directory to iterate over. * * @param filename the directory name * @param error exception return object or #NULL * @returns new iterator, or #NULL on error */ DBusDirIter* _dbus_directory_open (const DBusString *filename, DBusError *error) { DIR *d; DBusDirIter *iter; const char *filename_c; _DBUS_ASSERT_ERROR_IS_CLEAR (error); filename_c = _dbus_string_get_const_data (filename); d = opendir (filename_c); if (d == NULL) { dbus_set_error (error, _dbus_error_from_errno (errno), "Failed to read directory \"%s\": %s", filename_c, _dbus_strerror (errno)); return NULL; } iter = dbus_new0 (DBusDirIter, 1); if (iter == NULL) { closedir (d); dbus_set_error (error, DBUS_ERROR_NO_MEMORY, "Could not allocate memory for directory iterator"); return NULL; } iter->d = d; return iter; } /* Calculate the required buffer size (in bytes) for directory * entries read from the given directory handle. Return -1 if this * this cannot be done. * * If you use autoconf, include fpathconf and dirfd in your * AC_CHECK_FUNCS list. Otherwise use some other method to detect * and use them where available. */ static dbus_bool_t dirent_buf_size(DIR * dirp, size_t *size) { long name_max; # if defined(HAVE_FPATHCONF) && defined(_PC_NAME_MAX) # if defined(HAVE_DIRFD) name_max = fpathconf(dirfd(dirp), _PC_NAME_MAX); # elif defined(HAVE_DDFD) name_max = fpathconf(dirp->dd_fd, _PC_NAME_MAX); # else name_max = fpathconf(dirp->__dd_fd, _PC_NAME_MAX); # endif /* HAVE_DIRFD */ if (name_max == -1) # if defined(NAME_MAX) name_max = NAME_MAX; # else return FALSE; # endif # elif defined(MAXNAMELEN) name_max = MAXNAMELEN; # else # if defined(NAME_MAX) name_max = NAME_MAX; # else # error "buffer size for readdir_r cannot be determined" # endif # endif if (size) *size = (size_t)offsetof(struct dirent, d_name) + name_max + 1; else return FALSE; return TRUE; } /** * Get next file in the directory. Will not return "." or ".." on * UNIX. If an error occurs, the contents of "filename" are * undefined. The error is never set if the function succeeds. * * @param iter the iterator * @param filename string to be set to the next file in the dir * @param error return location for error * @returns #TRUE if filename was filled in with a new filename */ dbus_bool_t _dbus_directory_get_next_file (DBusDirIter *iter, DBusString *filename, DBusError *error) { struct dirent *d, *ent; size_t buf_size; int err; _DBUS_ASSERT_ERROR_IS_CLEAR (error); if (!dirent_buf_size (iter->d, &buf_size)) { dbus_set_error (error, DBUS_ERROR_FAILED, "Can't calculate buffer size when reading directory"); return FALSE; } d = (struct dirent *)dbus_malloc (buf_size); if (!d) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, "No memory to read directory entry"); return FALSE; } again: err = readdir_r (iter->d, d, &ent); if (err || !ent) { if (err != 0) dbus_set_error (error, _dbus_error_from_errno (err), "%s", _dbus_strerror (err)); dbus_free (d); return FALSE; } else if (ent->d_name[0] == '.' && (ent->d_name[1] == '\0' || (ent->d_name[1] == '.' && ent->d_name[2] == '\0'))) goto again; else { _dbus_string_set_length (filename, 0); if (!_dbus_string_append (filename, ent->d_name)) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, "No memory to read directory entry"); dbus_free (d); return FALSE; } else { dbus_free (d); return TRUE; } } } /** * Closes a directory iteration. */ void _dbus_directory_close (DBusDirIter *iter) { closedir (iter->d); dbus_free (iter); } static dbus_bool_t fill_user_info_from_group (struct group *g, DBusGroupInfo *info, DBusError *error) { _dbus_assert (g->gr_name != NULL); info->gid = g->gr_gid; info->groupname = _dbus_strdup (g->gr_name); /* info->members = dbus_strdupv (g->gr_mem) */ if (info->groupname == NULL) { dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL); return FALSE; } return TRUE; } static dbus_bool_t fill_group_info (DBusGroupInfo *info, dbus_gid_t gid, const DBusString *groupname, DBusError *error) { const char *group_c_str; _dbus_assert (groupname != NULL || gid != DBUS_GID_UNSET); _dbus_assert (groupname == NULL || gid == DBUS_GID_UNSET); if (groupname) group_c_str = _dbus_string_get_const_data (groupname); else group_c_str = NULL; /* For now assuming that the getgrnam() and getgrgid() flavors * always correspond to the pwnam flavors, if not we have * to add more configure checks. */ #if defined (HAVE_POSIX_GETPWNAM_R) || defined (HAVE_NONPOSIX_GETPWNAM_R) { struct group *g; int result; char buf[1024]; struct group g_str; g = NULL; #ifdef HAVE_POSIX_GETPWNAM_R if (group_c_str) result = getgrnam_r (group_c_str, &g_str, buf, sizeof (buf), &g); else result = getgrgid_r (gid, &g_str, buf, sizeof (buf), &g); #else g = getgrnam_r (group_c_str, &g_str, buf, sizeof (buf)); result = 0; #endif /* !HAVE_POSIX_GETPWNAM_R */ if (result == 0 && g == &g_str) { return fill_user_info_from_group (g, info, error); } else { dbus_set_error (error, _dbus_error_from_errno (errno), "Group %s unknown or failed to look it up\n", group_c_str ? group_c_str : "???"); return FALSE; } } #else /* ! HAVE_GETPWNAM_R */ { /* I guess we're screwed on thread safety here */ struct group *g; g = getgrnam (group_c_str); if (g != NULL) { return fill_user_info_from_group (g, info, error); } else { dbus_set_error (error, _dbus_error_from_errno (errno), "Group %s unknown or failed to look it up\n", group_c_str ? group_c_str : "???"); return FALSE; } } #endif /* ! HAVE_GETPWNAM_R */ } /** * Initializes the given DBusGroupInfo struct * with information about the given group name. * * @param info the group info struct * @param groupname name of group * @param error the error return * @returns #FALSE if error is set */ dbus_bool_t _dbus_group_info_fill (DBusGroupInfo *info, const DBusString *groupname, DBusError *error) { return fill_group_info (info, DBUS_GID_UNSET, groupname, error); } /** * Initializes the given DBusGroupInfo struct * with information about the given group ID. * * @param info the group info struct * @param gid group ID * @param error the error return * @returns #FALSE if error is set */ dbus_bool_t _dbus_group_info_fill_gid (DBusGroupInfo *info, dbus_gid_t gid, DBusError *error) { return fill_group_info (info, gid, NULL, error); } /** @} */ /* End of DBusInternalsUtils functions */ /** * @addtogroup DBusString * * @{ */ /** * Get the directory name from a complete filename * @param filename the filename * @param dirname string to append directory name to * @returns #FALSE if no memory */ dbus_bool_t _dbus_string_get_dirname (const DBusString *filename, DBusString *dirname) { int sep; _dbus_assert (filename != dirname); _dbus_assert (filename != NULL); _dbus_assert (dirname != NULL); /* Ignore any separators on the end */ sep = _dbus_string_get_length (filename); if (sep == 0) return _dbus_string_append (dirname, "."); /* empty string passed in */ while (sep > 0 && _dbus_string_get_byte (filename, sep - 1) == '/') --sep; _dbus_assert (sep >= 0); if (sep == 0) return _dbus_string_append (dirname, "/"); /* Now find the previous separator */ _dbus_string_find_byte_backward (filename, sep, '/', &sep); if (sep < 0) return _dbus_string_append (dirname, "."); /* skip multiple separators */ while (sep > 0 && _dbus_string_get_byte (filename, sep - 1) == '/') --sep; _dbus_assert (sep >= 0); if (sep == 0 && _dbus_string_get_byte (filename, 0) == '/') return _dbus_string_append (dirname, "/"); else return _dbus_string_copy_len (filename, 0, sep - 0, dirname, _dbus_string_get_length (dirname)); } /** @} */ /* DBusString stuff */