156 lines
3.2 KiB
C
156 lines
3.2 KiB
C
/*
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* udev-kvm-check.c
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*
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* Copyright 2018 Red Hat, Inc.
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*
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* This is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <ctype.h>
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#include <syslog.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define DEFAULT 0
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#define FACILITY "kvm"
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#define SYSCONFIG_KVM "/etc/sysconfig/kvm"
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#define COUNT_MSG \
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"%d %s now active"
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int get_threshold_from_file(FILE *fp)
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{
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static const char key[] = "THRESHOLD=";
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int pos = 0;
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int thres;
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int ch;
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start:
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/* State START - at beginning of line, search for beginning of "THRESHOLD="
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* string.
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*/
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ch = getc(fp);
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if (ch == EOF) {
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return DEFAULT;
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}
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if (isspace(ch)) {
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goto start;
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}
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if (ch == 'T') {
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pos = 1;
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goto key;
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}
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goto eol;
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eol:
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/* State EOL - loop until end of line */
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ch = getc(fp);
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if (ch == EOF) {
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return DEFAULT;
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}
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if (ch == '\n') {
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goto start;
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}
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goto eol;
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key:
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/* State KEY - match "THRESHOLD=" string, go to THRESHOLD if found */
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ch = getc(fp);
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if (ch == EOF) {
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return DEFAULT;
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}
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if (ch == key[pos]) {
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pos++;
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if (key[pos] == 0) {
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goto threshold;
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} else {
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goto key;
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}
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}
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goto eol;
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threshold:
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/* State THRESHOLD - parse number using fscanf, expect comment or space
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* or EOL.
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*/
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ch = getc(fp);
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if (ch == EOF) {
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return DEFAULT;
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}
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if (!isdigit(ch)) {
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goto eol;
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}
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ungetc(ch, fp);
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if (fscanf(fp, "%d", &thres) != 1) {
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return DEFAULT;
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}
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ch = getc(fp);
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if (ch == '#' || ch == EOF || ch == '\n' || isspace(ch)) {
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return thres;
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}
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goto eol;
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}
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int get_threshold()
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{
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FILE *fp = fopen(SYSCONFIG_KVM, "r");
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int val;
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if (!fp) {
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return DEFAULT;
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}
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val = get_threshold_from_file(fp);
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fclose (fp);
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return val;
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}
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const char *guest(int count)
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{
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return (count == 1 ? "guest" : "guests");
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}
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void emit_count_message(int count)
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{
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openlog(FACILITY, LOG_CONS, LOG_USER);
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syslog(LOG_INFO, COUNT_MSG, count, guest(count));
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closelog();
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}
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int main(int argc, char **argv)
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{
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int count, threshold;
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if (argc < 3)
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exit(1);
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count = atoi(argv[1]);
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threshold = get_threshold();
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if (!strcmp(argv[2], "create")) {
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if (threshold == 0 || count > threshold) {
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emit_count_message(count);
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}
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} else {
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if (count >= threshold) {
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emit_count_message(count);
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}
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}
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return 0;
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}
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