ref: 481ae719406aa288aa28ab040e13f3f573fe6776
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);
}