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contrib-munin/plugins/system/1sec/if1sec-c.c

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2015-06-01 22:12:47 +02:00
/*
* if1sec C plugin
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdint.h>
#include <inttypes.h>
#include <fcntl.h>
#include <time.h>
#include <sys/file.h>
#define PROC_STAT "/proc/net/dev"
#define PLUGIN_NAME "if1sec-c"
int fail(char* msg) {
perror(msg);
return 1;
}
/* Returns the ifname from a /proc/net/dev line
* It will return an inside pointer to line, and modifiy the end with a \0
*/
char* get_ifname_from_procstatline(char* line) {
char *ifname;
for (ifname = line; (*ifname) == ' '; ifname ++);
char *ifname_end;
for (ifname_end = ifname; (*ifname_end) != ':'; ifname_end ++);
(*ifname_end) = '\0';
return ifname;
}
int config() {
/* Get the number of if */
int f;
if ( !(f=open(PROC_STAT, O_RDONLY)) ) {
return fail("cannot open " PROC_STAT);
}
// Starting with -2, since the 2 lines on top are header lines
int nif = -2;
const int buffer_size = 64 * 1024;
char buffer[buffer_size];
// whole /proc/stat can be read in 1 syscall
if (read(f, buffer, buffer_size) <= 0) {
return fail("cannot read " PROC_STAT);
}
// tokenization per-line
char* line; char *saveptr;
char* newl = "\n";
for (line = strtok_r(buffer, newl, &saveptr); line; line = strtok_r(NULL, newl, &saveptr)) {
// Skip the header lines
if (nif ++ < 0) { continue; }
char* if_name = get_ifname_from_procstatline(line);
printf(
"multigraph if_%s_1sec" "\n"
"graph_order down up" "\n"
"graph_title %s traffic" "\n"
"graph_category system::1sec" "\n"
"graph_vlabel bits in (-) / out (+) per ${graph_period}" "\n"
"graph_data_size custom 1d, 10s for 1w, 1m for 1t, 5m for 1y" "\n"
, if_name, if_name
);
printf(
"down.label -" "\n"
"down.type DERIVE" "\n"
"down.graph no" "\n"
"down.cdef down,8,*" "\n"
"down.min 0" "\n"
"up.label bps" "\n"
"up.type DERIVE" "\n"
"up.negative down" "\n"
"up.cdef down,8,*" "\n"
"up.min 0" "\n"
);
}
close(f);
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() {
/* 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);
/* Reading /proc/stat */
int f = open(PROC_STAT, O_RDONLY);
/* open the spoolfile */
int cache_file = open(cache_filename, O_CREAT | O_APPEND | O_WRONLY, S_IRUSR | S_IWUSR);
/* loop each second */
while (1) {
/* wait until next second */
time_t epoch = wait_until_next_second();
const int buffer_size = 64 * 1024;
char buffer[buffer_size];
if (lseek(f, 0, SEEK_SET) < 0) {
return fail("cannot seek " PROC_STAT);
}
// whole PROC file can be read in 1 syscall
if (read(f, buffer, buffer_size) <= 0) {
return fail("cannot read " PROC_STAT);
}
// ignore the 1rst line
char* line; char *saveptr;
const char* newl = "\n";
/* lock */
flock(cache_file, LOCK_EX);
int nif = -2;
for (line = strtok_r(buffer, newl, &saveptr); line; line = strtok_r(NULL, newl, &saveptr)) {
// Skip the header lines
if (nif ++ < 0) { continue; }
char if_id[64];
uint_fast64_t r_bytes, r_packets, r_errs, r_drop, r_fifo, r_frame, r_compressed, r_multicast;
uint_fast64_t t_bytes, t_packets, t_errs, t_drop, t_fifo, t_frame, t_compressed, t_multicast;
sscanf(line, "%s"
" "
"%llu %llu %llu %llu %llu %llu %llu %llu"
" "
"%llu %llu %llu %llu %llu %llu %llu %llu"
, if_id
, &r_bytes, &r_packets, &r_errs, &r_drop, &r_fifo, &r_frame, &r_compressed, &r_multicast
, &t_bytes, &t_packets, &t_errs, &t_drop, &t_fifo, &t_frame, &t_compressed, &t_multicast
);
// Remove trailing ':' of if_id
if_id[strlen(if_id) - 1] = '\0';
char out_buffer[1024];
sprintf(out_buffer,
"multigraph if_%s_1sec" "\n"
"up.value %ld:%llu" "\n"
"down.value %ld:%llu" "\n"
, if_id
, epoch, r_bytes
, epoch, t_bytes
);
write(cache_file, out_buffer, strlen(out_buffer));
}
/* unlock */
flock(cache_file, LOCK_UN);
}
close(cache_file);
close(f);
return 0;
}
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);
return 0;
}
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("/" PLUGIN_NAME ".") + strlen("pid") + 1); pid_filename[0] = '\0';
cache_filename = malloc(MUNIN_PLUGSTATE_length + strlen("/" PLUGIN_NAME ".") + strlen("value") + 1); cache_filename[0] = '\0';
strcat(pid_filename, MUNIN_PLUGSTATE);
strcat(pid_filename, "/" PLUGIN_NAME "." "pid");
strcat(cache_filename, MUNIN_PLUGSTATE);
strcat(cache_filename, "/" PLUGIN_NAME "." "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();
}
/***** DEMO
/proc/net/dev sample
Inter-| Receive | Transmit
face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed
lo: 4364 54 0 0 0 0 0 0 4364 54 0 0 0 0 0 0
eth0: 3459461624 22016512 0 70 0 0 0 0 3670486138 18117144 0 0 0 0 0 0
*****/