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#include "logging.h"
#include "netcheck.h"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/stat.h>
#define OPTPARSE_IMPLEMENTATION
#define OPTPARSE_API static
#include "optparse.h"
const char *logfile = "netmon.log";
// which host to ping. If NULL, test tcp instead
const char *pingdest = NULL;
// TODO support blanks
// cmd to be executed. If NULL, reboot
const char *failcmd = "reboot";
// seconds to sleep between checks
unsigned int check_interval_seconds = 30;
// how many failures to reboot the system
int max_check_failure = 5;
// should run as a daemon process
int as_daemon = 0;
// TODO make failure_sleep_seconds configurable
// seconds to sleep before resuming check after a network failure is detected
unsigned int failure_sleep_seconds = 60;
volatile int failure_detected = 0;
void *logger = NULL;
void daemonize() {
pid_t pid = 0;
pid_t sid = 0;
pid = fork();
if (pid < 0) {
perror("fork()");
log_error(logger, "fork() failed.");
exit(1);
}
if (pid > 0) {
char buf[32];
snprintf(buf, 31, "Child process: %d", pid);
log_info(logger, buf);
exit(0); // exit parent process
}
// unmask the file mode
umask(0);
// set new session
sid = setsid();
if (sid < 0) {
perror("setsid()");
log_error(logger, "setsid() failed.");
exit(1);
}
if (chdir("/")) {
perror("chdir()");
log_error(logger, "chdir() failed,");
exit(1);
}
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
}
///**
// * Read and escape a string, then write to another buffer, with length limit.
// * @param si
// * @param so
// * @param maxlen
// */
//void escape(const char *si, char *so, size_t maxlen) {
// size_t wb = 0; // bytes written
// char c[4] = {'\0'};
// while ((c[0] = *si++) != '\0') {
// const char *s;
// switch (c[0]) {
// case '\r':
// s = "\r";
// break;
// case '\n':
// s = "\n";
// break;
// case '\t':
// s = "\t";
// break;
// case '\v':
// s = "\v";
// break;
// case '\b':
// s = "\b";
// break;
// case '\a':
// s = "\a";
// break;
// case '\f':
// s = "\f";
// break;
// default:
// s = c;
// break;
// }
// strcpy(so, s)
// }
//}
void loop() {
// check network and sleep
// if fails too many times continuously, set require_reboot flag and return
int failures = 0;
#pragma clang diagnostic push
#pragma ide diagnostic ignored "EndlessLoop"
while (1) {
log_info(logger, "Check network.");
if ((pingdest == NULL) ?
(check_tcp(logger) != 0) :
(check_ping(logger, pingdest, NULL) != 0)) {
++failures;
char buf[64];
snprintf(buf, 63, "Network failure detected. counter=%d", failures);
log_info(logger, buf);
} else {
log_info(logger, "Network is OK.");
failures = 0;
}
if (failures > max_check_failure) {
log_info(logger, "Max failure times exceeded.");
failure_detected = 1;
failures = 0; // reset failure counter
// handle a network failure event
char tmp[256];
snprintf(tmp, 255, "Run system command `%s`.", failcmd);
log_info(logger, tmp);
system(failcmd);
snprintf(tmp, 255, "Wait %d secs before resume checking.\n",
failure_sleep_seconds);
log_debug(logger, tmp);
unsigned t = failure_sleep_seconds;
while ((t = sleep(t)));
continue; // resume checking right now
}
log_info(logger, "Sleeping...");
unsigned int t = check_interval_seconds;
while ((t = sleep(t)));
}
#pragma clang diagnostic pop
}
int main(int argc, char *argv[]) {
struct optparse_long opts[] = {
{"interval", 't', OPTPARSE_REQUIRED},
{"max-failure", 'n', OPTPARSE_REQUIRED},
{"log", 'l', OPTPARSE_REQUIRED},
{"ping", 'p', OPTPARSE_REQUIRED},
{"command", 'c', OPTPARSE_REQUIRED},
{"daemon", 'd', OPTPARSE_NONE},
{"help", 'h', OPTPARSE_NONE},
{0}
};
int option;
struct optparse options;
char *end;
optparse_init(&options, argv);
while ((option = optparse_long(&options, opts, NULL)) != -1) {
switch (option) {
case 't':
check_interval_seconds = (int) strtol(options.optarg, &end, 10);
if (*end != '\0') {
die("Invalid check interval: %s\n", options.optarg);
}
if (check_interval_seconds <= 0) {
die("Check interval should be positive.\n");
}
break;
case 'n':
max_check_failure = (int) strtol(options.optarg, &end, 10);
if (*end != '\0') {
die("Invalid max check failure times: %s\n",
options.optarg);
}
if (max_check_failure < 0) {
die("Max check failure times should not be negative.\n");
}
break;
case 'l':
logfile = strdup(options.optarg);
break;
case 'p':
pingdest = strdup(options.optarg);
break;
case 'c':
failcmd = strdup(options.optarg);
break;
case 'd':
as_daemon = 1;
break;
case 'h':
printf("Usage: %s "
"[-t <check_interval>] "
"[-n <max_failure>] "
"[-l <log_file>] "
"[-c <cmd>] "
"[-p <ping_host>] "
"[-d]\n",
argv[0]);
exit(0);
default:
die("%s: %s\n", argv[0], options.errmsg);
}
}
logger = log_init(logfile);
log_debug(logger, "DEBUG logging is enabled.");
if (as_daemon) {
log_info(logger, "Daemonizing...");
daemonize();
}
log_info(logger, "netmon is started.");
loop();
log_info(logger, "netmon is stopped.");
log_free(logger);
return 0;
}
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