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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <curl/curl.h>
#include "monitor.h"
typedef enum {
TYPE_REACH,
TYPE_DNS,
TYPE_WEB
} type_t;
const char *type_str[] = { "reach", "dns", "web" };
typedef enum {
STATUS_DOWN,
STATUS_UP
} status_t;
typedef struct {
type_t type;
char *target;
status_t status;
} target_t;
static target_t targets[256];
static size_t target_n = 0;
static char timestr[256];
static size_t
write_data(void *ptr, size_t size, size_t nmemb, void *stream)
{
return size * nmemb;
}
int
monitor_init(const char *cfg_file) {
FILE *cfgf = fopen(cfg_file, "r");
if (!cfgf) {
fprintf(stderr, "Error opening config: %s\n", strerror(errno));
return -1;
}
printf("monitor targets:\n");
char line[256];
while (fgets(line, sizeof(line), cfgf)) {
if (*line == '#' || *line == '\n')
continue;
line[strlen(line) - 1] = '\0'; /* strip \n */
char *type = line;
char *target = strchr(line, '=');
if (!target) {
fprintf(stderr, "malformed config line: %s\n", line);
continue;
}
*target = '\0';
target++;
if (strcmp(type, "reach") == 0)
targets[target_n].type = TYPE_REACH;
else if (strcmp(type, "dns") == 0)
targets[target_n].type = TYPE_DNS;
else if (strcmp(type, "web") == 0)
targets[target_n].type = TYPE_WEB;
targets[target_n].target = strdup(target);
targets[target_n].status = STATUS_DOWN;
printf("\t%s: %s\n", type_str[targets[target_n].type],
targets[target_n].target);
target_n++;
}
fclose(cfgf);
CURLcode res = curl_global_init(CURL_GLOBAL_ALL);
if (res) {
fprintf(stderr, "Error initializing cURL: %s\n",
curl_easy_strerror(res));
return -1;
}
return 0;
}
const char *
monitor_generate_status_html()
{
static char buff[65535];
static char *status_html[] = {
"<td class=\"down\">down</td>",
"<td class=\"up\">up</td>"
};
char *pos = buff;
for (size_t i = 0; i < target_n; i++) {
pos += snprintf(pos, 65535,
"<tr><td>%s</td><td>%s</td>%s</tr>\n",
type_str[targets[i].type],
targets[i].target,
status_html[targets[i].status]);
}
return buff;
}
static int
check_reach(const char *target)
{
static char ping_cmd[256];
snprintf(ping_cmd, 256, "ping -W1 -c1 %s > /dev/null", target);
/* i know */
if (system(ping_cmd) == 0) {
printf("reachable\n");
return STATUS_UP;
} else {
printf("unreachable\n");
return STATUS_DOWN;
}
}
static int
check_dns(const char *name)
{
static char dig_cmd[512];
static char cmd_out[256];
snprintf(dig_cmd, 512, "dig +nocookie +short %s NS", name);
FILE *pf = popen(dig_cmd, "r");
fread(cmd_out, 256, 1, pf);
pclose(pf);
if (*cmd_out == '\0') {
printf("no ns\n");
return STATUS_DOWN;
}
*strchr(cmd_out, '\n') = '\0';
snprintf(dig_cmd, 512, "dig +nocookie +short @%s %s A", cmd_out, name);
pf = popen(dig_cmd, "r");
fread(cmd_out, 256, 1, pf);
pclose(pf);
if (*cmd_out == '\0') {
printf("no a\n");
return STATUS_DOWN;
}
*strchr(cmd_out, '\n') = '\0';
printf("%s\n", cmd_out);
return STATUS_UP;
}
static int
check_http(const char *endpoint)
{
CURL *curl = curl_easy_init();
if (!curl) {
fprintf(stderr, "Error allocating cURL handle\n");
return -1;
}
//curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_TIMEOUT, 1);
curl_easy_setopt(curl, CURLOPT_URL, endpoint);
CURLcode curl_code = curl_easy_perform(curl);
if (curl_code != CURLE_OK) {
printf("curl_easy_perform() failed: %s\n",
curl_easy_strerror(curl_code));
return STATUS_DOWN;
}
long http_code;
curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_code);
curl_easy_cleanup(curl);
printf("%ld\n", http_code);
return http_code == 200 ? STATUS_UP : STATUS_DOWN;
}
void
monitor_check()
{
static size_t check_num = 0;
time_t time_now = time(NULL);
struct tm *tm_now = gmtime(&time_now);
strftime(timestr, 256, "%Y-%m-%d %H-%M-%S", tm_now);
static const int (*check_funcs[])(const char *) = {
check_reach,
check_dns,
check_http
};
for (size_t i = 0; i < target_n; i++) {
printf("[%s] [monitor] check #%ld %s: %s: ",
timestr, check_num, type_str[targets[i].type], targets[i].target);
targets[i].status = check_funcs[targets[i].type](targets[i].target);
}
check_num++;
}
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