+ /* On Linux we can optimize this a bit if /proc is available. If it
+ isn't available, fall back to the brute force way. */
+
+ d = opendir ("/proc/self/fd");
+ if (d)
+ {
+ for (;;)
+ {
+ struct dirent buf, *de;
+ int k, fd;
+ long l;
+ char *e = NULL;
+
+ k = readdir_r (d, &buf, &de);
+ if (k != 0 || !de)
+ break;
+
+ if (de->d_name[0] == '.')
+ continue;
+
+ errno = 0;
+ l = strtol (de->d_name, &e, 10);
+ if (errno != 0 || e == NULL || *e != '\0')
+ continue;
+
+ fd = (int) l;
+ if (fd < 3)
+ continue;
+
+ if (fd == dirfd (d))
+ continue;
+
+ close (fd);
+ }
+
+ closedir (d);
+ return;
+ }
+#endif
+
+ maxfds = sysconf (_SC_OPEN_MAX);
+
+ /* Pick something reasonable if for some reason sysconf says
+ * unlimited.
+ */
+ if (maxfds < 0)
+ maxfds = 1024;
+
+ /* close all inherited fds */
+ for (i = 3; i < maxfds; i++)
+ close (i);
+}
+
+/**
+ * **NOTE**: If you modify this function, please also consider making
+ * the corresponding change in GLib. See
+ * glib/gutils.c:g_check_setuid().
+ *
+ * Returns TRUE if the current process was executed as setuid (or an
+ * equivalent __libc_enable_secure is available). See:
+ * http://osdir.com/ml/linux.lfs.hardened/2007-04/msg00032.html
+ */
+dbus_bool_t
+_dbus_check_setuid (void)
+{
+ /* TODO: get __libc_enable_secure exported from glibc.
+ * See http://www.openwall.com/lists/owl-dev/2012/08/14/1
+ */
+#if 0 && defined(HAVE_LIBC_ENABLE_SECURE)
+ {
+ /* See glibc/include/unistd.h */
+ extern int __libc_enable_secure;
+ return __libc_enable_secure;
+ }
+#elif defined(HAVE_ISSETUGID)
+ /* BSD: http://www.freebsd.org/cgi/man.cgi?query=issetugid&sektion=2 */
+ return issetugid ();
+#else
+ uid_t ruid, euid, suid; /* Real, effective and saved user ID's */
+ gid_t rgid, egid, sgid; /* Real, effective and saved group ID's */
+
+ /* We call into this function from _dbus_threads_init_platform_specific()
+ * to make sure these are initialized before we start threading. */
+ static dbus_bool_t check_setuid_initialised;
+ static dbus_bool_t is_setuid;
+
+ if (_DBUS_UNLIKELY (!check_setuid_initialised))
+ {
+#ifdef HAVE_GETRESUID
+ if (getresuid (&ruid, &euid, &suid) != 0 ||
+ getresgid (&rgid, &egid, &sgid) != 0)
+#endif /* HAVE_GETRESUID */
+ {
+ suid = ruid = getuid ();
+ sgid = rgid = getgid ();
+ euid = geteuid ();
+ egid = getegid ();
+ }
+
+ check_setuid_initialised = TRUE;
+ is_setuid = (ruid != euid || ruid != suid ||
+ rgid != egid || rgid != sgid);
+
+ }
+ return is_setuid;
+#endif
+}
+
+/**
+ * Read the address from the socket and append it to the string