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#include <u.h>
#include <libc.h>
/* MAXHOSTNAMELEN is in sys/param.h */
#define MAXHOSTNAMELEN 64
char lockstring[MAXHOSTNAMELEN+8];
void
main(int argc, char *argv[]) {
char *lockfile;
int fd, ppid, ssize;
struct Dir *statbuf;
if (argc != 4) {
fprint(2, "usage: LOCK lockfile hostname ppid\n");
exits("lock failed on usage");
}
lockfile = argv[1];
if ((fd=create(lockfile, OLOCK|ORDWR, 0666)) < 0) {
exits("lock failed on create");
}
ppid = atoi(argv[3]);
ssize = sprint(lockstring, "%s %s\n", argv[2], argv[3]);
if (write(fd, lockstring, ssize) != ssize) {
fprint(2, "LOCK:write(): %r\n");
exits("lock failed on write to lockfile");
}
switch(fork()) {
default:
exits("");
case 0:
break;
case -1:
fprint(2, "LOCK:fork(): %r\n");
exits("lock failed on fork");
}
for(;;) {
statbuf = dirfstat(fd);
if(statbuf == nil)
break;
if (statbuf->length == 0){
free(statbuf);
break;
}
free(statbuf);
if (write(fd, "", 0) < 0)
break;
sleep(3000);
}
close(fd);
postnote(PNGROUP, ppid, "kill");
exits("");
}
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