/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2007 - 2013 Red Hat, Inc.
*/
#include "nm-default.h"
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include "nm-utils/nm-vpn-plugin-macros.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;
}