/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * Copyright (C) 2007 - 2013 Red Hat, Inc. */ #include "libnm-glib-aux/nm-default-glib.h" #include #include #include #include "libnm-glib-aux/nm-logging-syslog.h" #include "nm-dhcp-helper-api.h" /*****************************************************************************/ #if NM_MORE_LOGGING #define _NMLOG_ENABLED(level) TRUE #else #define _NMLOG_ENABLED(level) ((level) <= LOG_ERR) #endif #define _NMLOG(always_enabled, level, ...) \ G_STMT_START \ { \ if ((always_enabled) || _NMLOG_ENABLED(level)) { \ GTimeVal _tv; \ \ g_get_current_time(&_tv); \ g_print( \ "nm-dhcp-helper[%ld] %-7s [%ld.%04ld] " _NM_UTILS_MACRO_FIRST(__VA_ARGS__) "\n", \ (long) getpid(), \ nm_utils_syslog_to_str(level), \ _tv.tv_sec, \ _tv.tv_usec / 100 _NM_UTILS_MACRO_REST(__VA_ARGS__)); \ } \ } \ G_STMT_END #define _LOGD(...) _NMLOG(TRUE, LOG_INFO, __VA_ARGS__) #define _LOGI(...) _NMLOG(TRUE, LOG_NOTICE, __VA_ARGS__) #define _LOGW(...) _NMLOG(TRUE, LOG_WARNING, __VA_ARGS__) #define _LOGE(...) _NMLOG(TRUE, LOG_ERR, __VA_ARGS__) #define _LOGd(...) _NMLOG(FALSE, LOG_INFO, __VA_ARGS__) #define _LOGi(...) _NMLOG(FALSE, LOG_NOTICE, __VA_ARGS__) #define _LOGw(...) _NMLOG(FALSE, LOG_WARNING, __VA_ARGS__) /*****************************************************************************/ static GVariant * build_signal_parameters(void) { const char *const *environ_iter; GVariantBuilder builder; g_variant_builder_init(&builder, G_VARIANT_TYPE_VARDICT); /* List environment and format for dbus dict */ for (environ_iter = (const char *const *) environ; *environ_iter; environ_iter++) { static const char *const ignore_with_prefix_list[] = {"PATH", "SHLVL", "_", "PWD", "dhc_dbus", NULL}; const char * item = *environ_iter; gs_free char * name = NULL; const char * val; const char *const *p; val = strchr(item, '='); if (!val || item == val) continue; name = g_strndup(item, val - item); val += 1; /* Ignore non-DHCP-related environment variables */ for (p = ignore_with_prefix_list; *p; p++) { if (strncmp(name, *p, strlen(*p)) == 0) goto next; } if (!g_utf8_validate(name, -1, NULL)) continue; /* Value passed as a byte array rather than a string, because there are * no character encoding guarantees with DHCP, and D-Bus requires * strings to be UTF-8. * * Note that we can't use g_variant_new_bytestring() here, because that * includes the trailing '\0'. (??!?) */ g_variant_builder_add(&builder, "{sv}", name, g_variant_new_fixed_array(G_VARIANT_TYPE_BYTE, val, strlen(val), 1)); next:; } return g_variant_ref_sink(g_variant_new("(a{sv})", &builder)); } static void kill_pid(void) { const char *pid_str; pid_t pid = 0; pid_str = getenv("pid"); if (pid_str) pid = strtol(pid_str, NULL, 10); if (pid) { _LOGI("a fatal error occurred, kill dhclient instance with pid %d", pid); kill(pid, SIGTERM); } } int main(int argc, char *argv[]) { gs_unref_object GDBusConnection *connection = NULL; gs_free_error GError *error = NULL; gs_unref_variant GVariant *parameters = NULL; gs_unref_variant GVariant *result = NULL; gboolean success = FALSE; guint try_count; gint64 time_start; gint64 time_end; /* Connecting to the unix socket can fail with EAGAIN if there are too * many pending connections and the server can't accept them in time * before reaching backlog capacity. Ideally the server should increase * the backlog length, but GLib doesn't provide a way to change it for a * GDBus server. Retry for up to 5 seconds in case of failure. */ time_start = g_get_monotonic_time(); time_end = time_start + (5000 * 1000L); try_count = 0; do_connect: try_count++; connection = g_dbus_connection_new_for_address_sync("unix:path=" NMRUNDIR "/private-dhcp", G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT, NULL, NULL, &error); if (!connection) { if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK)) { gint64 time_remaining = time_end - g_get_monotonic_time(); gint64 interval; if (time_remaining > 0) { _LOGi("failure to connect: %s (retry %u, waited %lld ms)", error->message, try_count, (long long) (time_end - time_remaining - time_start) / 1000); interval = NM_CLAMP((gint64)(100L * (1L << NM_MIN(try_count, 31))), 5000, 100000); g_usleep(NM_MIN(interval, time_remaining)); g_clear_error(&error); goto do_connect; } } g_dbus_error_strip_remote_error(error); _LOGE("could not connect to NetworkManager D-Bus socket: %s", error->message); goto out; } parameters = build_signal_parameters(); time_end = g_get_monotonic_time() + (200 * 1000L); /* retry for at most 200 milliseconds */ try_count = 0; do_notify: try_count++; result = g_dbus_connection_call_sync(connection, NULL, NM_DHCP_HELPER_SERVER_OBJECT_PATH, NM_DHCP_HELPER_SERVER_INTERFACE_NAME, NM_DHCP_HELPER_SERVER_METHOD_NOTIFY, parameters, NULL, G_DBUS_CALL_FLAGS_NONE, 1000, NULL, &error); if (!result) { gs_free char *s_err = NULL; s_err = g_dbus_error_get_remote_error(error); if (NM_IN_STRSET(s_err, "org.freedesktop.DBus.Error.UnknownMethod")) { gint64 remaining_time = time_end - g_get_monotonic_time(); gint64 interval; /* I am not sure that a race can actually happen, as we register the object * on the server side during GDBusServer:new-connection signal. * * However, there was also a race for subscribing to an event, so let's just * do some retry. */ if (remaining_time > 0) { _LOGi("failure to call notify: %s (retry %u)", error->message, try_count); interval = NM_CLAMP((gint64)(100L * (1L << NM_MIN(try_count, 31))), 5000, 25000); g_usleep(NM_MIN(interval, remaining_time)); g_clear_error(&error); goto do_notify; } } _LOGW("failure to call notify: %s (try signal via Event)", error->message); g_clear_error(&error); /* for backward compatibility, try to emit the signal. There is no stable * API between the dhcp-helper and NetworkManager. However, while upgrading * the NetworkManager package, a newer helper might want to notify an * older server, which still uses the "Event". */ if (!g_dbus_connection_emit_signal(connection, NULL, "/", NM_DHCP_CLIENT_DBUS_IFACE, "Event", parameters, &error)) { g_dbus_error_strip_remote_error(error); _LOGE("could not send DHCP Event signal: %s", error->message); goto out; } /* We were able to send the asynchronous Event. Consider that a success. */ success = TRUE; } else success = TRUE; if (!g_dbus_connection_flush_sync(connection, NULL, &error)) { g_dbus_error_strip_remote_error(error); _LOGE("could not flush D-Bus connection: %s", error->message); success = FALSE; goto out; } out: if (!success) kill_pid(); return success ? EXIT_SUCCESS : EXIT_FAILURE; }