57 lines
773 B
C
57 lines
773 B
C
#include <plan9.h>
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#include <fcall.h>
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#include <u9fs.h>
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#include <sys/time.h>
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static long
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getseed(void)
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{
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struct timeval tv;
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long seed;
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int fd, len;
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len = 0;
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fd = open("/dev/urandom", O_RDONLY);
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if(fd > 0){
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len = readn(fd, &seed, sizeof(seed));
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close(fd);
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}
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if(len != sizeof(seed)){
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gettimeofday(&tv, nil);
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seed = tv.tv_sec ^ tv.tv_usec ^ (getpid()<<8);
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}
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return seed;
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}
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static int seeded;
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void
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randombytes(uchar *r, uint nr)
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{
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int i;
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ulong l;
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if(!seeded){
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seeded=1;
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srand48(getseed());
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}
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for(i=0; i+4<=nr; i+=4,r+=4){
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l = (ulong)mrand48();
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r[0] = l;
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r[1] = l>>8;
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r[2] = l>>16;
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r[3] = l>>24;
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}
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if(i<nr){
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l = (ulong)mrand48();
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switch(nr-i){
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case 3:
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r[2] = l>>16;
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case 2:
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r[1] = l>>8;
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case 1:
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r[0] = l;
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}
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}
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}
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