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- #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;
- srand48(getseed());
- }
- for(i=0; i+4<=nr; i+=4,r+=4){
- l = (ulong)mrand48();
- r[0] = l;
- r[1] = l>>8;
- r[2] = l>>16;
- r[3] = l>>24;
- }
- if(i<nr){
- l = (ulong)mrand48();
- switch(nr-i){
- case 3:
- r[2] = l>>16;
- case 2:
- r[1] = l>>8;
- case 1:
- r[0] = l;
- }
- }
- }
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