Subversion Repositories planix.SVN

#include <plan9.h>
#include <fcall.h>
#include <u9fs.h>
#include <stdlib.h>
#include <sys/time.h>
#include <fcntl.h>

static long
getseed(void)
{
        struct timeval tv;
        long seed;
        int fd, len;

        len = 0;
        fd = open("/dev/urandom", O_RDONLY);
        if(fd > 0){
                len = readn(fd, &seed, sizeof(seed));
                close(fd);
        }
        if(len != sizeof(seed)){
                gettimeofday(&tv, nil);
                seed = tv.tv_sec ^ tv.tv_usec ^ (getpid()<<8);
        }
        return seed;
}

static int seeded;

void
randombytes(uchar *r, uint nr)
{
        int i;
        ulong l;

        if(!seeded){
                seeded=1;
                srandom(getseed());
        }
        for(i=0; i+4<=nr; i+=4,r+=4){
                l = (ulong)random();
                r[0] = l;
                r[1] = l>>8;
                r[2] = l>>16;
                r[3] = l>>24;
        }
        if(i<nr){
                l = (ulong)random();
                switch(nr-i){
                case 3:
                        r[2] = l>>16;
                case 2:
                        r[1] = l>>8;
                case 1:
                        r[0] = l;
                }
        }
}