/* $Id: rtwatchd.c,v 1.5 2019/12/24 20:22:04 admin Exp $
*
* Setzt rtprio von Prozessen ab wenn das system einfriert.
*
* Prios: 31 = rtprio:79 = langsamste
* 0 = rtprio:48 = schnellste
* Aufteilung: 31 - 21 sollen packet-handling/VoIP nicht bremsen
* 21 - 18 packet-handling/VoIP
* 18 - 10 vorrangig über packet-h./VoIP, aber überwacht
* 9 der Watchdog
* 8 - 0 vom Watchdog ignoriert
*/
# include <sys/types.h>
# include <sys/rtprio.h>
# include <sys/sysctl.h>
# include <sys/user.h>
# include <sys/priority.h>
# include <sys/stat.h>
# include <sys/mman.h>
# include <unistd.h>
# include <stdio.h>
# include <stdlib.h>
# include <malloc_np.h>
# include <string.h>
# include <syslog.h>
# define THE_MIB "kern.proc.all"
# define RESERVE 250000
# define MYPRIO 9
# define LOOPTIME 135
extern int errno;
char *progname;
void usage( void )
{
fprintf( stderr, "Usage: %s file-to-watch\n", progname);
exit(1);
}
time_t getmtime( char *file )
{
struct stat attr;
if(stat(file, &attr) != 0)
attr.st_mtime = 0;
return(attr.st_mtime);
}
void slowdown(int active)
{
size_t size;
int count;
struct kinfo_proc *buffer, *p;
struct rtprocs {
pid_t pid;
char *name;
struct rtprocs *next;
} *pilist = NULL, **b = &pilist, *c, *d;
struct rtprio prio;
if(sysctlbyname(THE_MIB, NULL, &size, NULL, 0) != 0) {
syslog(LOG_ALERT,
"failed to access %s: %s\n", THE_MIB, strerror(errno));
exit(1);
}
size += RESERVE; /* lieber ein bischen mehr allozieren */
if((buffer = malloc(size)) == NULL) {
syslog(LOG_ALERT, "malloc() failure %d, exiting\n", errno);
exit(1);
}
if(sysctlbyname(THE_MIB, buffer, &size, NULL, 0) != 0) {
syslog(LOG_ALERT, "failure %d retrieving procs, exiting\n", errno);
exit(1);
}
count = size / sizeof(struct kinfo_proc);
p = buffer;
while(count-- != 0) {
if(p->ki_pri.pri_class == PRI_REALTIME &&
p->ki_pri.pri_user > PRI_MIN_REALTIME + MYPRIO) {
struct rtprocs *a = pilist;
int schonda = 0;
/* Die liste enthält threads, wir wollen die pid nur einmal */
while(a != NULL) {
if(a->pid == p->ki_pid)
schonda = 1;
a = a->next;
}
if (schonda == 0) {
if((*b = malloc(sizeof(struct rtprocs))) == NULL) {
syslog(LOG_ALERT, "malloc() failure %d, exiting\n", errno);
exit(1);
}
/* irnwie sieht das als linked-list komisch aus, aber funzt */
(*b)->pid = p->ki_pid;
(*b)->name = p->ki_comm;
(*b)->next = NULL;
b = &((*b)->next);
}
}
p++;
}
prio.type = RTP_PRIO_NORMAL;
prio.prio = 0; /* Keine Ahnung was man da setzen soll */
c = pilist;
while(c != NULL) {
if(active) {
rtprio(RTP_SET, c->pid, &prio);
syslog(LOG_CRIT, "revoking rtprio for pid=%d (%s)\n", c->pid, c->name);
}
d = c->next;
free(c);
c = d;
}
free(buffer);
}
int main (int argc, char *argv[])
{
struct rtprio prio;
char *filen;
time_t filemtime, last;
progname = argv[0];
if(argc != 2 || access(argv[1], F_OK) != 0)
usage();
filen = argv[1];
/* Auf Realtimeprio wechseln */
prio.type = RTP_PRIO_REALTIME;
prio.prio = MYPRIO;
if(rtprio(RTP_SET, 0, &prio) != 0) {
syslog(LOG_ALERT, "failed to set realtime priority: %s\n",
strerror(errno));
exit(1);
}
/* Testaufruf */
slowdown(0);
/* Aktionen nach log/messages reporten */
openlog("rtwatchd", LOG_CONS, LOG_DAEMON);
/* Das ist nur falls swap-exhaustion, sollte nie passieren */
if(madvise(0, 0, MADV_PROTECT) != 0)
syslog(LOG_ALERT, "failure %d to madvise\n", errno);
/* Das ist interessanter, aber konfliktiert mit zfs wired */
if(mlockall(MCL_CURRENT | MCL_FUTURE) != 0) {
syslog(LOG_ALERT, "failure %d to mlockall\n", errno);
}
time(&last);
while(1) {
sleep(LOOPTIME);
if(getmtime(filen) < last) {
slowdown(1);
exit(0);
}
time(&last);
}
}
