ref: bbf532dba8d0462c7ef2f00b2646e5ac5b04bd62
dir: /sys/src/libc/9sys/getppid.c/
#include <u.h>
#include <libc.h>
int
getppid(void)
{
char b[20];
int f;
memset(b, 0, sizeof(b));
f = open("/dev/ppid", 0);
if(f >= 0) {
read(f, b, sizeof(b));
close(f);
}
return atol(b);
}