double
stir_from_programs(void)
{
int c;
double entropy, total_entropy;
unsigned char hash[SHA_DIGEST_LENGTH];
total_entropy = 0;
for(c = 0; entropy_cmds[c].path != NULL; c++) {
if (!entropy_cmds[c].badness) {
/* Hash output from command */
entropy = hash_command_output(&entropy_cmds[c],
hash);
/* Scale back estimate by command's rate */
entropy *= entropy_cmds[c].rate;
/* Upper bound of entropy is SHA_DIGEST_LENGTH */
if (entropy > SHA_DIGEST_LENGTH)
entropy = SHA_DIGEST_LENGTH;
/* Stir it in */
RAND_add(hash, sizeof(hash), entropy);
debug3("Got %0.2f bytes of entropy from '%s'",
entropy, entropy_cmds[c].cmdstring);
total_entropy += entropy;
/* Execution time should be a bit unpredictable */
total_entropy += stir_gettimeofday(0.05);
total_entropy += stir_clock(0.05);
total_entropy += stir_rusage(RUSAGE_SELF, 0.1);
total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1);
} else {
debug2("Command '%s' disabled (badness %d)",
entropy_cmds[c].cmdstring,
entropy_cmds[c].badness);
if (entropy_cmds[c].badness > 0)
entropy_cmds[c].badness--;
}
}
return total_entropy;
}
bool
hash_multicommand_output(struct mdfour *hash, const char *commands,
const char *compiler)
{
char *command_string, *command, *p, *saveptr = NULL;
bool ok = true;
command_string = x_strdup(commands);
p = command_string;
while ((command = strtok_r(p, ";", &saveptr))) {
if (!hash_command_output(hash, command, compiler)) {
ok = false;
}
p = NULL;
}
free(command_string);
return ok;
}