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#include "config.h"
#include "genrand.h"
#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/time.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#undef MAX
#define MAX(a, b) (((a) > (b)) ? (a) : (b))
#undef MIN
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
/* AIX requires this to be the first thing in the file. */
#if defined(__GNUC__)
# if defined(__STRICT_ANSI__)
# define alloca __builtin_alloca
# endif
#else
# ifdef HAVE_ALLOCA_H
# include <alloca.h>
# elif defined(_AIX)
#pragma alloca
# elif !defined(alloca) /* predefined by HP cc +Olibcalls */
char *alloca ();
# endif
#endif
static int
genrand_dev(unsigned char *buffer, int buf_len)
{
int fd;
fd = open("/dev/random", O_RDONLY);
if(fd < 0)
return 0;
if(read(fd, buffer, buf_len) < buf_len)
{
close(fd);
return 0;
}
close(fd);
return 1;
}
static volatile int received_alarm = 0;
static void
handle_alarm(int signum)
{
received_alarm = 1;
}
static unsigned char
hashlong(long val)
{
unsigned char retval, *ptr;
int i;
for(ptr = (unsigned char *)&val, i = 0; i < sizeof(val); i++)
retval ^= ptr[i];
return retval;
}
static int
genrand_unix(unsigned char *buffer, int buf_len)
{
struct sigaction sa, oldsa;
struct itimerval it, oldit;
int i;
long min, max;
long *counts;
double diff;
long *uninit;
counts = alloca(buf_len * sizeof(long));
memset(&sa, 0, sizeof(sa));
sa.sa_handler = handle_alarm;
sigaction(SIGALRM, &sa, &oldsa);
memset(&it, 0, sizeof(it));
it.it_value.tv_usec = 1;
getitimer(ITIMER_REAL, &oldit);
for(i = 0, min = LONG_MAX, max = 0; i < buf_len; i++)
{
received_alarm = 0;
setitimer(ITIMER_REAL, &it, NULL);
for(counts[i] = 0; !received_alarm; counts[i]++);
max = MAX(counts[i], max);
min = MIN(counts[i], min);
}
if(!(max - min))
return 0;
diff = max - min;
uninit = alloca(buf_len * sizeof(long)); /* Purposely not initialized */
for(i = 0; i < buf_len; i++)
{
long diffval;
diffval = counts[i] - min;
buffer[i] ^= (unsigned char)( ((double) (diffval*256) / diff )) ^ hashlong(uninit[i]);
}
setitimer(ITIMER_REAL, &oldit, NULL);
sigaction(SIGALRM, &oldsa, NULL);
return 1;
}
void
esound_genrand(unsigned char *buffer, int buf_len)
{
if(genrand_dev(buffer, buf_len))
return;
else if(genrand_unix(buffer, buf_len))
return;
else
abort();
}
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