URandom.xs

#define PERL_NO_GET_CONTEXT
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include <sys/types.h>
#ifdef HAVE_CRYPT_URANDOM_NATIVE_GETRANDOM
#include <sys/random.h>
#else
#ifdef HAVE_CRYPT_URANDOM_SYSCALL_GETRANDOM
#include <sys/syscall.h>
#else
#ifdef HAVE_CRYPT_URANDOM_NATIVE_ARC4RANDOM_BUF
#include <sys/random.h>
#else
#ifdef HAVE_CRYPT_URANDOM_UNISTD_ARC4RANDOM_BUF
#include <unistd.h>
#else
#ifdef HAVE_CRYPT_URANDOM_STDLIB_ARC4RANDOM_BUF
#include <stdlib.h>
#endif
#endif
#endif
#endif
#endif
#ifdef GRND_NONBLOCK
#else
#define GRND_NONBLOCK	0x0001
#endif
#include <errno.h>

MODULE = Crypt::URandom  PACKAGE = Crypt::URandom  PREFIX = crypt_urandom_
PROTOTYPES: ENABLE

SV *
crypt_urandom_getrandom(length)
        ssize_t length
    PREINIT:
        char *data;
        int result;
    CODE:
        Newx(data, length + 1u, char);
#if defined(__sun) && defined(__SVR4)
        if (length == 0) {
            result = 0;
        } else {
#endif
      GETRANDOM:
#ifdef HAVE_CRYPT_URANDOM_NATIVE_GETRANDOM
        result = getrandom(data, length, GRND_NONBLOCK);
#else
#ifdef HAVE_CRYPT_URANDOM_SYSCALL_GETRANDOM
        result = syscall(SYS_getrandom, data, length, GRND_NONBLOCK);
#else
#ifdef HAVE_CRYPT_URANDOM_NATIVE_ARC4RANDOM_BUF
        arc4random_buf(data, length);
        result = length;
#else
#ifdef HAVE_CRYPT_URANDOM_UNISTD_ARC4RANDOM_BUF
        arc4random_buf(data, length);
        result = length;
#else
#ifdef HAVE_CRYPT_URANDOM_STDLIB_ARC4RANDOM_BUF
        arc4random_buf(data, length);
        result = length;
#else
        croak("Unable to find getrandom or an alternative");
#endif
#endif
#endif
#endif
#endif
        if (result != length) {
            if (errno == EINTR) {
                goto GETRANDOM;
            } else {
                Safefree(data);
                croak("Failed to getrandom:%s", strerror(errno));
            }
        }
#if defined(__sun) && defined(__SVR4)
        }
#endif
        data[result] = '\0';
        RETVAL = newSVpv(data, result);
        Safefree(data);
    OUTPUT:
        RETVAL