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#include <sys/types.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/event.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
int printer_ready;
char * printer;
char * queue_dir;
char * trigger;
#define BUFLEN 50
char queue_dir_new[BUFLEN];
char trigger_cmd[BUFLEN];
int open_and_subscribe(struct kevent * change, const char * path)
{
int f;
f = open(path, O_RDONLY);
if (f == -1) {
perror("open");
return -1;
}
EV_SET(change, f, EVFILT_VNODE,
EV_ADD | EV_ENABLE | EV_ONESHOT,
NOTE_DELETE | NOTE_EXTEND |
NOTE_WRITE | NOTE_ATTRIB,
0, 0);
}
int check_printer_status(){
struct stat buf;
//printf("%s\n", printer);
int r = stat(printer, &buf);
if (r<0) {
if (printer_ready != 0) {
printf("Printer offline\n");
}
printer_ready = 0;
if (errno == ENOENT) {
printf("Printer not detected\n");
} else {
perror("stat");
return -1;
}
} else {
if (printer_ready != 1) {
printf("Printer online\n");
print_loop(printer, queue_dir);
}
printer_ready = 1;
}
return 0;
}
int print_loop()
{
FILE * p;
int status;
char buf[BUFLEN];
printf("Print loop\n");
p = popen(trigger_cmd, "r");
if (p == NULL)
perror("popen");
while (fgets(buf, BUFLEN, p) != NULL)
printf("%s", buf);
status = pclose(p);
if (status != 0) {
printf("Trigger exited with status %d\n", status);
}
return status;
}
int main(int argc, const char * argv[])
{
int fd, fq, kq, nev;
struct kevent change;
struct kevent event;
int len;
if (argc != 4) {
fprintf(stderr, "usage: %s printer queue_dir trigger\n", argv[0]);
return -1;
}
printer = strdup(argv[1]);
queue_dir = strdup(argv[2]);
trigger = strdup(argv[3]);
len = snprintf(trigger_cmd, BUFLEN, "%s %s %s", trigger, printer, queue_dir);
if (len >= BUFLEN - 1) {
printf("Buffer too small\n");
return -1;
}
len = snprintf(queue_dir_new, BUFLEN, "%s/new", queue_dir);
if (len >= BUFLEN - 1) {
printf("Buffer too small\n");
return -1;
}
printer_ready = 0;
kq = kqueue();
if (kq == -1)
perror("kqueue");
fq = open_and_subscribe(&change, queue_dir_new);
struct timespec timeout;
timeout.tv_sec = 5;
timeout.tv_nsec = 0;
check_printer_status();
for (;;) {
nev = kevent(kq, &change, 1, &event, 1, &timeout);
if (nev == -1)
perror("kevent");
if (nev == 0) { // timeout
check_printer_status();
} else if (nev > 0) {
if (event.fflags & NOTE_DELETE) {
continue;
}
printf("Got event for %d\n", event.ident);
if (printer_ready) {
print_loop(printer, queue_dir, trigger);
}
}
}
close(kq);
close(fq);
close(fd);
return EXIT_SUCCESS;
}
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