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#include <ctype.h>
#include <syslog.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define DEFAULT 0
#define FACILITY "kvm"
#define SYSCONFIG_KVM "/etc/sysconfig/kvm"
#define COUNT_MSG \
"%d %s now active"
#define SUBSCRIPTION_MSG \
"%d %s now active; your Red Hat Enterprise Linux subscription" \
" limit is %d guests. Please review your Red Hat Enterprise Linux" \
" subscription agreement or contact your Red Hat" \
" support representative for more information. You" \
" may review the Red Hat Enterprise subscription" \
" limits at http://www.redhat.com/rhel-virt-limits"
int get_threshold_from_file(FILE *fp)
{
static const char key[] = "THRESHOLD=";
int pos = 0;
int thres;
char ch;
start:
/* State START - at beginning of line, search for beginning of "THRESHOLD="
* string.
*/
ch = getc(fp);
if (ch == EOF) {
return DEFAULT;
}
if (isspace(ch)) {
goto start;
}
if (ch == 'T') {
pos = 1;
goto key;
}
goto eol;
eol:
/* State EOL - loop until end of line */
ch = getc(fp);
if (ch == EOF) {
return DEFAULT;
}
if (ch == '\n') {
goto start;
}
goto eol;
key:
/* State KEY - match "THRESHOLD=" string, go to THRESHOLD if found */
ch = getc(fp);
if (ch == EOF) {
return DEFAULT;
}
if (ch == key[pos]) {
pos++;
if (key[pos] == 0) {
goto threshold;
} else {
goto key;
}
}
goto eol;
threshold:
/* State THRESHOLD - parse number using fscanf, expect comment or space
* or EOL.
*/
ch = getc(fp);
if (ch == EOF) {
return DEFAULT;
}
if (!isdigit(ch)) {
goto eol;
}
ungetc(ch, fp);
if (fscanf(fp, "%d", &thres) != 1) {
return DEFAULT;
}
ch = getc(fp);
if (ch == '#' || ch == EOF || ch == '\n' || isspace(ch)) {
return thres;
}
goto eol;
}
int get_threshold()
{
FILE *fp = fopen(SYSCONFIG_KVM, "r");
int val = get_threshold_from_file(fp);
fclose (fp);
return val;
}
const char *guest(int count)
{
return (count == 1 ? "guest" : "guests");
}
void emit_count_message(int count)
{
openlog(FACILITY, LOG_CONS, LOG_USER);
syslog(LOG_INFO, COUNT_MSG, count, guest(count));
closelog();
}
void emit_subscription_message(int count, int threshold)
{
openlog(FACILITY, LOG_CONS, LOG_USER);
syslog(LOG_WARNING, SUBSCRIPTION_MSG, count, guest(count), threshold);
closelog();
}
int main(int argc, char **argv)
{
int count, threshold;
if (argc < 3)
exit(1);
count = atoi(argv[1]);
threshold = get_threshold();
if (!strcmp(argv[2], "create")) {
if (threshold == 0) {
emit_count_message(count);
} else if (count > threshold) {
emit_subscription_message(count, threshold);
}
} else {
if (count >= threshold) {
emit_count_message(count);
}
}
return 0;
}
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