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contrib-munin/plugins/system/multicpu1sec/multicpu1sec-c.c

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/*
* multicpu1sec C plugin
*/
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#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <sys/file.h>
#define PROC_STAT "/proc/stat"
int fail(char* msg) {
perror(msg);
return 1;
}
int config() {
/* Get the number of CPU */
FILE* f;
if ( !(f=fopen(PROC_STAT, "r")) ) {
return fail("cannot open " PROC_STAT);
}
// Starting with -1, since the first line is the "global cpu line"
int ncpu = -1;
while (! feof(f)) {
char buffer[1024];
if (fgets(buffer, 1024, f) == 0) {
break;
}
if (! strncmp(buffer, "cpu", 3)) ncpu ++;
}
fclose(f);
printf(
"graph_title multicpu1sec\n"
"graph_category system::1sec\n"
"graph_vlabel average cpu use %%\n"
"graph_scale no\n"
"graph_total All CPUs\n"
"update_rate 1\n"
"graph_data_size custom 1d, 10s for 1w, 1m for 1t, 5m for 1y\n"
);
int i;
for (i = 0; i < ncpu; i++) {
printf("cpu%d.label CPU %d\n", i, i);
printf("cpu%d.draw %s\n", i, "AREASTACK");
printf("cpu%d.type %s\n", i, "DERIVE");
printf("cpu%d.min 0\n", i);
}
return 0;
}
char* pid_filename;
char* cache_filename;
/* Wait until the next second, and return the EPOCH */
time_t wait_until_next_second() {
struct timespec tp;
clock_gettime(CLOCK_REALTIME, &tp);
time_t current_epoch = tp.tv_sec;
long nsec_to_sleep = 1000*1000*1000 - tp.tv_nsec;
/* Only sleep if needed */
if (nsec_to_sleep > 0) {
tp.tv_sec = 0;
tp.tv_nsec = nsec_to_sleep;
nanosleep(&tp, NULL);
}
return current_epoch + 1;
}
int acquire() {
2015-03-04 00:16:41 +01:00
/* fork ourselves if not asked otherwise */
char* no_fork = getenv("no_fork");
if (! no_fork || strcmp("1", no_fork)) {
if (fork()) return;
// we are the child, complete the daemonization
/* Close standard IO */
fclose(stdin);
fclose(stdout);
fclose(stderr);
/* create new session and process group */
setsid();
}
/* write the pid */
FILE* pid_file = fopen(pid_filename, "w");
fprintf(pid_file, "%d\n", getpid());
fclose(pid_file);
/* loop each second */
while (1) {
/* wait until next second */
time_t epoch = wait_until_next_second();
/* Reading /proc/stat */
FILE* f = fopen(PROC_STAT, "r");
// Read and ignore the 1rst line
char buffer[1024];
fgets(buffer, 1024, f);
/* open the spoolfile */
FILE* cache_file = fopen(cache_filename, "a");
/* lock */
flock(fileno(cache_file), LOCK_EX);
while (! feof(f)) {
if (fgets(buffer, 1024, f) == 0) {
// EOF
break;
}
// Not on CPU lines anymore
if (strncmp(buffer, "cpu", 3)) break;
char cpu_id[64];
long usr, nice, sys, idle, iowait, irq, softirq;
sscanf(buffer, "%s %ld %ld %ld %ld %ld %ld %ld", cpu_id, &usr, &nice, &sys, &idle, &iowait, &irq, &softirq);
long used = usr + nice + sys + iowait + irq + softirq;
fprintf(cache_file, "%s.value %ld:%ld\n", cpu_id, epoch, used);
}
fclose(cache_file);
fclose(f);
}
}
int fetch() {
FILE* cache_file = fopen(cache_filename, "r+");
/* lock */
flock(fileno(cache_file), LOCK_EX);
/* cat the cache_file to stdout */
char buffer[1024];
while (fgets(buffer, 1024, cache_file)) {
printf("%s", buffer);
}
ftruncate(fileno(cache_file), 0);
fclose(cache_file);
}
int main(int argc, char **argv) {
/* resolve paths */
char *MUNIN_PLUGSTATE = getenv("MUNIN_PLUGSTATE");
/* Default is current directory */
if (! MUNIN_PLUGSTATE) MUNIN_PLUGSTATE = ".";
size_t MUNIN_PLUGSTATE_length = strlen(MUNIN_PLUGSTATE);
pid_filename = malloc(MUNIN_PLUGSTATE_length + strlen("/multicpu1sec.") + strlen("pid") + 1); pid_filename[0] = '\0';
cache_filename = malloc(MUNIN_PLUGSTATE_length + strlen("/multicpu1sec.") + strlen("value") + 1); cache_filename[0] = '\0';
strcat(pid_filename, MUNIN_PLUGSTATE);
strcat(pid_filename, "/multicpu1sec.pid");
strcat(cache_filename, MUNIN_PLUGSTATE);
strcat(cache_filename, "/multicpu1sec.value");
if (argc > 1) {
char* first_arg = argv[1];
if (! strcmp(first_arg, "config")) {
return config();
}
if (! strcmp(first_arg, "acquire")) {
return acquire();
}
}
return fetch();
}