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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>
const char *logfile = "netmon.log";
const char *pingdest = NULL; // which host to ping. If NULL, test tcp instead
const char *failcmd = "reboot"; // cmd to be executed. If NULL, reboot // TODO support blanks
unsigned int check_interval_seconds = 30; // seconds to sleep between checks
int max_check_failure = 5; // how many failures to reboot the system
int as_daemon = 0; // should run as a daemon process
unsigned int failure_sleep_seconds = 60; // seconds to sleep before resuming check after a network failure is detected
// TODO make failure_sleep_seconds configurable
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);
}
chdir("/");
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[]) {
for (int i = 1; i < argc; ++i) {
if (!strcmp(argv[i], "-t")) {
check_interval_seconds = atoi(argv[i + 1]);
if (check_interval_seconds <= 0) {
fprintf(stderr, "check interval should be positive.\n");
return -1;
}
++i; // skip next value
} else if (!strcmp(argv[i], "-n")) {
max_check_failure = atoi(argv[i + 1]);
if (max_check_failure < 0) {
fprintf(stderr, "max check failure should not be negative.\n");
return -1;
}
++i; // skip next value
} else if (!strcmp(argv[i], "-l")) {
logfile = argv[i + 1];
++i; // skip next value
} else if (!strcmp(argv[i], "-p")) {
pingdest = argv[i + 1];
++i; // skip next value
} else if (!strcmp(argv[i], "-c")) {
char *s = argv[i + 1];
unsigned long len = strlen(s);
if (len == 0) {
fprintf(stderr, "Empty fail command.\n");
return -1;
}
failcmd = s;
fprintf(stderr, "Fail command is set to `%s`.\n", failcmd);
++i; // skip next value
} else if (!strcmp(argv[i], "-d")) {
as_daemon = 1;
} else {
int invalid = strcmp(argv[i], "-h") != 0 && strcmp(argv[i], "--help") != 0;
if (invalid) printf("Unrecognized parameter \"%s\".\n", argv[i]);
printf("Usage:\n"
" %s [-t <check_interval>] [-n <max_failure>] [-l <log_file>] [-c <cmd>] [-p <ping_host>] [-d]\n",
argv[0]);
return invalid != 0;
}
}
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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