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/*
* Copyright (C) 2011 Tildeslash Ltd. All rights reserved.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
*
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
#include <config.h>
#ifdef HAVE_STDIO_H
#include <stdio.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "monitor.h"
#include "state.h"
/**
* Manage service information persistently. Service data is saved to
* a state file when monit runs in daemon mode for each poll
* cycle. Monit use this file to maintain service data persistently
* during reload or restart. The location of the state file may be
* set from the command line or set in the monitrc file, if not set,
* the default is ~/.monit.state.
*
* @author Jan-Henrik Haukeland, <hauk@tildeslash.com>
* @file
*/
/* ------------------------------------------------------------- Definitions */
/**
* Fields from the Service_T object type, which we are interested in
* when handling the state.
*/
typedef struct mystate {
char name[STRLEN];
int mode;
int nstart;
int ncycle;
int monitor;
unsigned long long error;
} State_T;
/* -------------------------------------------------------------- Prototypes */
static void close_state(FILE *);
static FILE *open_state(const char *mode);
static void clone_state(Service_T, State_T *);
static void update_service_state(Service_T, State_T *);
/* ------------------------------------------------------------------ Public */
/**
* Save service state information to the state file
*/
void State_save() {
int l= 0;
Service_T s;
State_T state;
FILE *S= NULL;
if(! (S= open_state("w")))
return;
l= Util_getNumberOfServices();
if(fwrite(&l, 1, sizeof (int), S) != sizeof(int)) {
LogError("%s: Unable to save monit state information to '%s'\n",
prog, Run.statefile);
goto error;
}
for(s= servicelist; s; s= s->next) {
clone_state(s, &state);
if(fwrite(&state, 1, sizeof(State_T), S) != sizeof(State_T)) {
LogError("%s: An error occured when saving monit state information "
"for the service %s\n", prog, s->name);
goto error;
}
}
error:
close_state(S);
}
/**
* Check if we should update current services with persistent state
* information. The logic is as follows: Iff a state file is present
* *and* older than the running monit daemon's lock file we have had a
* crash and should update data from the state file.
* @return TRUE if the state should be updated otherwise FALSE
*/
int State_shouldUpdate() {
if(File_exist(Run.statefile) && File_exist(Run.pidfile)) {
return (File_getTimestamp(Run.pidfile, S_IFREG) >
File_getTimestamp(Run.statefile, S_IFREG));
}
return FALSE;
}
/**
* Update the current service list with data from the state file. We
* do *only* change services found in *both* the monitrc file and in
* the state file. The algorithm:
*
* Assume the control file was changed and a new service (B) was added
* so the monitrc file now contains the services: A B and C. The
* running monit daemon only knows the services A and C. Upon restart
* after a crash the monit daemon first read the monitrc file and
* creates the service list structure with A B and C. We then read the
* state file and update the service A and C since they are found in
* the state file, B is not found in this file and therefore not
* changed.
*
* The same strategy is used if a service was removed, e.g. if the
* service A was removed from monitrc; when reading the state file,
* service A is not found in the current service list (the list is
* always generated from monitrc) and therefore A is simply discarded.
*
* Finally, after the monit service state is updated this function
* writes the new state file.
*/
void State_update() {
int i;
int l= 0;
State_T s;
FILE *S= NULL;
Service_T service;
int has_error= FALSE;
if(! (S= open_state("r")))
return;
errno= 0;
if(fread(&l, 1, sizeof (int), S) != sizeof(int)) {
LogError("%s: Unable to read monit state information from '%s'\n",
prog, Run.statefile);
has_error= TRUE;
goto error;
}
if(l > 0) {
for(i=0; i<l; i++) {
if(fread(&s, 1, sizeof(State_T), S) != sizeof(State_T)) {
LogError("%s: An error occured when updating monit state information\n",
prog);
has_error= TRUE;
goto error;
}
if((service= Util_getService(s.name))) {
update_service_state(service, &s);
}
}
}
error:
close_state(S);
if(!has_error)
State_save();
}
/* ----------------------------------------------------------------- Private */
static FILE *open_state(const char *mode) {
FILE *S= NULL;
ASSERT(Run.statefile);
umask(MYPIDMASK);
if((S= fopen(Run.statefile, mode)) == NULL) {
LogError("%s: Cannot open the monit state file '%s' -- %s\n",
prog, Run.statefile, STRERROR);
return NULL;
}
return S;
}
static void close_state(FILE *S) {
if(fclose(S) != 0)
LogCritical("%s: Cannot close the monit state file '%s' -- %s\n", prog, Run.statefile, STRERROR);
}
static void clone_state(Service_T service, State_T *state) {
memset(state, 0, sizeof(State_T));
strncpy(state->name, service->name, sizeof(state->name) - 1);
state->name[sizeof(state->name) - 1] = 0;
state->nstart= service->nstart;
state->ncycle= service->ncycle;
state->monitor= service->monitor;
}
static void update_service_state(Service_T service, State_T *state) {
service->nstart= state->nstart;
service->ncycle= state->ncycle;
/* Keep services in initializing state unless the monitoring should be disabled */
if (state->monitor == MONITOR_NOT)
service->monitor= state->monitor;
}
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