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ifstatd/ifstatd.c
Babak Farrokhi 620e51230e - Improve pidfile handling 
- Clean shutdown if daemon is killed
- Prevent daemon from running twice
- Minor code cleanup and refactoring
2015-09-15 18:15:12 +04:30

338 lines
8.3 KiB
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/*-
* Copyright (c) 2015, Babak Farrokhi
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_types.h>
#include <ifaddrs.h>
#include <err.h>
#include <errno.h>
#include <signal.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>
#include <libutil.h>
#define IFA_STAT(s) (((struct if_data *)ifa->ifa_data)->ifi_ ## s)
#define RESOLUTION 10
struct iftot {
u_long ift_ip; /* input packets */
u_long ift_ie; /* input errors */
u_long ift_id; /* input drops */
u_long ift_op; /* output packets */
u_long ift_oe; /* output errors */
u_long ift_od; /* output drops */
u_long ift_co; /* collisions */
u_long ift_ib; /* input bytes */
u_long ift_ob; /* output bytes */
};
/* Globals */
char *program_name = "ifstatd_";
char *interface;
char *pid_filename;
char *cache_filename;
struct pidfh *pfh;
/*
* Prepare for a clean shutdown
*/
void daemon_shutdown()
{
pidfile_remove(pfh);
}
/*
* Act upon receiving signals
*/
void signal_handler(int sig)
{
switch(sig) {
case SIGHUP:
case SIGINT:
case SIGTERM:
daemon_shutdown();
exit(EXIT_SUCCESS);
break;
default:
break;
}
}
/*
* Obtain stats for interface(s).
*/
static void fill_iftot(struct iftot *st)
{
struct ifaddrs *ifap, *ifa;
bool found = false;
if (getifaddrs(&ifap) != 0)
err(EX_OSERR, "getifaddrs");
bzero(st, sizeof(*st));
for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
if (ifa->ifa_addr->sa_family != AF_LINK)
continue;
if (interface) {
if (strcmp(ifa->ifa_name, interface) == 0)
found = true;
else
continue;
}
st->ift_ip += IFA_STAT(ipackets);
st->ift_ib += IFA_STAT(ibytes);
st->ift_op += IFA_STAT(opackets);
st->ift_ob += IFA_STAT(obytes);
}
if (interface && found == false)
err(EX_DATAERR, "interface %s not found", interface);
freeifaddrs(ifap);
}
/*
* Print out munin plugin configuration
*/
int config(char *iface)
{
printf(
"graph_order rbytes obytes\n"
"graph_title %s Interface (%d seconds sampling)\n"
"graph_category network\n"
"graph_vlabel bits per second\n"
"update_rate %d\n"
"graph_data_size custom 1d, %ds for 1w, 1m for 1t, 5m for 1y\n"
"rbytes.label received\n"
"rbytes.type DERIVE\n"
"rbytes.graph no\n"
"rbytes.cdef rbytes,8,*\n"
"rbytes.min 0\n"
"obytes.label bps\n"
"obytes.type DERIVE\n"
"obytes.negative rbytes\n"
"obytes.cdef obytes,8,*\n"
"obytes.min 0\n"
"obytes.draw AREA\n"
,iface,RESOLUTION,RESOLUTION,RESOLUTION
);
return(0);
}
/*
* Wait for a certain amount of time
*/
time_t wait_for(int seconds) {
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 = seconds - 1;
tp.tv_nsec = nsec_to_sleep;
nanosleep(&tp, NULL);
}
return current_epoch + seconds;
}
/*
* Daemonize and persist pid
*/
int daemon_start()
{
struct iftot ift, *tot;
time_t epoch;
struct sigaction sig_action;
sigset_t sig_set;
pid_t otherpid;
tot = &ift;
char* no_fork = getenv("no_fork");
if (! no_fork || strcmp("1", no_fork)) {
/* Check if parent process id is set */
if (getppid() == 1)
{
/* PPID exists, therefore we are already a daemon */
return(EXIT_FAILURE);
}
/* Check if we can acquire the pid file */
pfh = pidfile_open(pid_filename, 0600, &otherpid);
if (pfh == NULL) {
if (errno == EEXIST) {
errx(EXIT_FAILURE, "Daemon already running, pid: %jd.", (intmax_t)otherpid);
}
warn("Cannot open or create pidfile: %s", pid_filename);
}
/* fork ourselves if not asked otherwise */
if (fork())
{
return(EXIT_SUCCESS);
}
/* we are the child, complete the daemonization */
/* Close standard IO */
fclose(stdin);
fclose(stdout);
fclose(stderr);
/* Block unnecessary signals */
sigemptyset(&sig_set);
sigaddset(&sig_set, SIGCHLD); /* ignore child - i.e. we don't need to wait for it */
sigaddset(&sig_set, SIGTSTP); /* ignore Tty stop signals */
sigaddset(&sig_set, SIGTTOU); /* ignore Tty background writes */
sigaddset(&sig_set, SIGTTIN); /* ignore Tty background reads */
sigprocmask(SIG_BLOCK, &sig_set, NULL); /* Block the above specified signals */
/* Catch necessary signals */
sig_action.sa_handler = signal_handler;
sigemptyset(&sig_action.sa_mask);
sig_action.sa_flags = 0;
sigaction(SIGTERM, &sig_action, NULL);
sigaction(SIGHUP, &sig_action, NULL);
sigaction(SIGINT, &sig_action, NULL);
/* create new session and process group */
setsid();
/* persist pid */
pidfile_write(pfh);
}
FILE *cache_file = fopen(cache_filename, "a");
/* looping to collect traffic stat every RESOLUTION seconds */
while(1) {
epoch=wait_for(RESOLUTION);
flockfile(cache_file);
fill_iftot(tot);
fprintf(cache_file, "obytes.value %ld:%lu\nrbytes.value %ld:%lu\n", epoch, tot->ift_ob, epoch, tot->ift_ib);
fflush(cache_file);
funlockfile(cache_file);
}
fclose(cache_file);
return(0);
}
int fetch()
{
/* this should return data from cache file */
FILE* cache_file = fopen(cache_filename, "r+");
/* lock */
flockfile(cache_file);
/* 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[])
{
if (argv[0] && argv[0][0])
program_name = argv[0];
/* figure out program name */
while (strchr(program_name, '/')) {
program_name=strchr(program_name, '/')+1;
}
/* extract interface name from plugin name */
if (strchr(program_name,'_')) {
interface=strchr(program_name,'_')+1;
}
/* program should always run with a valid
executable name */
if (strlen(interface) < 1) {
errx(EX_USAGE, "Please run from symlink");
}
/* resolve paths */
char *MUNIN_PLUGSTATE = getenv("MUNIN_PLUGSTATE");
/* Default is current directory */
if (!MUNIN_PLUGSTATE) MUNIN_PLUGSTATE = ".";
asprintf(&pid_filename, "%s/%s.pid", MUNIN_PLUGSTATE, program_name);
asprintf(&cache_filename, "%s/%s.value", MUNIN_PLUGSTATE, program_name);
if (argc > 1) {
char* first_arg = argv[1];
if (! strcmp(first_arg, "config")) {
return config(interface);
}
if (! strcmp(first_arg, "acquire")) {
return daemon_start();
}
}
return fetch();
}
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