@@ -1,3 +1,20 @@
+/*
+ * xenwatchdogd.c
+ *
+ * Watchdog based on Xen hypercall watchdog interface
+ *
+ * Copyright 2010-2024 Citrix Ltd and other contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * 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 Lesser General Public License for more details.
+ */
#include <err.h>
#include <limits.h>
@@ -10,6 +27,11 @@
#include <signal.h>
#include <stdio.h>
#include <stdbool.h>
+#include <getopt.h>
+
+#define WDOG_MIN_TIMEOUT 2
+#define WDOG_MIN_SLEEP 1
+#define WDOG_EXIT_TIMEOUT 300
static xc_interface *h;
static bool safeexit = false;
@@ -49,6 +71,26 @@ static void catch_usr1(int sig)
done = true;
}
+static void __attribute__((noreturn)) usage(int exit_code)
+{
+ FILE *out = exit_code ? stderr : stdout;
+
+ fprintf(out,
+ "Usage: xenwatchdog [OPTION]... <timeout> [<sleep>]\n"
+ " -h, --help\t\tDisplay this help text and exit.\n"
+ " -F, --foreground\tRun in foreground.\n"
+ " -x, --safe-exit\tDisable watchdog on orderly exit.\n"
+ "\t\t\tNote: default is to set a %d second timeout on exit.\n\n"
+ " timeout\t\tInteger seconds to arm the watchdog each time.\n"
+ "\t\t\tNote: minimum timeout is %d seconds.\n\n"
+ " sleep\t\t\tInteger seconds to sleep between arming the watchdog.\n"
+ "\t\t\tNote: sleep must be at least %d and less than timeout.\n"
+ "\t\t\tIf not specified then set to half the timeout.\n",
+ WDOG_EXIT_TIMEOUT, WDOG_MIN_TIMEOUT, WDOG_MIN_SLEEP
+ );
+ exit(exit_code);
+}
+
static int parse_secs(const char *arg, const char *what)
{
char *endptr;
@@ -66,21 +108,70 @@ int main(int argc, char **argv)
int id;
int t, s;
int ret;
+ bool daemon = true;
+
+ for ( ;; )
+ {
+ int option_index = 0, c;
+ static const struct option long_options[] =
+ {
+ { "help", no_argument, NULL, 'h' },
+ { "foreground", no_argument, NULL, 'F' },
+ { "safe-exit", no_argument, NULL, 'x' },
+ { NULL, 0, NULL, 0 },
+ };
+
+ c = getopt_long(argc, argv, "hFxD", long_options, &option_index);
+ if (c == -1)
+ break;
+
+ switch (c)
+ {
+ case 'h':
+ usage(EXIT_SUCCESS);
+
+ case 'F':
+ daemon = false;
+ break;
+
+ case 'x':
+ safeexit = true;
+ break;
+
+ default:
+ usage(EXIT_FAILURE);
+ }
+ }
- if (argc < 2)
- errx(EXIT_FAILURE, "usage: %s <timeout> <sleep>", argv[0]);
+ if (argc - optind < 1)
+ errx(EXIT_FAILURE, "timeout must be specified");
- daemonize();
-
- h = xc_interface_open(NULL, NULL, 0);
- if (h == NULL)
- err(EXIT_FAILURE, "xc_interface_open");
+ if (argc - optind > 2)
+ errx(EXIT_FAILURE, "too many arguments");
t = parse_secs(argv[optind], "timeout");
+ if (t < WDOG_MIN_TIMEOUT)
+ errx(EXIT_FAILURE, "Error: timeout must be at least %d seconds",
+ WDOG_MIN_TIMEOUT);
- s = t / 2;
- if (argc == 3)
+ ++optind;
+ if (optind < argc) {
s = parse_secs(argv[optind], "sleep");
+ if (s < WDOG_MIN_SLEEP)
+ errx(EXIT_FAILURE, "Error: sleep must be no less than %d",
+ WDOG_MIN_SLEEP);
+ if (s >= t)
+ errx(EXIT_FAILURE, "Error: sleep must be less than timeout");
+ }
+ else
+ s = t / 2;
+
+ if (daemon)
+ daemonize();
+
+ h = xc_interface_open(NULL, NULL, 0);
+ if (h == NULL)
+ err(EXIT_FAILURE, "xc_interface_open");
if (signal(SIGHUP, &catch_exit) == SIG_ERR)
err(EXIT_FAILURE, "signal");
@@ -105,6 +196,6 @@ int main(int argc, char **argv)
}
// Zero seconds timeout will disarm the watchdog timer
- xc_watchdog(h, id, safeexit ? 0 : 300);
+ xc_watchdog(h, id, safeexit ? 0 : WDOG_EXIT_TIMEOUT);
return 0;
}