include/qemu/guest-random.h

   1 /*
   2  * QEMU guest-visible random functions
   3  *
   4  * Copyright 2019 Linaro, Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  */
  11
  12 #ifndef QEMU_GUEST_RANDOM_H
  13 #define QEMU_GUEST_RANDOM_H
  14
  15 /**
  16  * qemu_guest_random_seed_main(const char *seedstr, Error **errp)
  17  * @seedstr: a non-NULL pointer to a C string
  18  * @errp: an error indicator
  19  *
  20  * The @seedstr value is that which accompanies the -seed argument.
  21  * This forces qemu_guest_getrandom into deterministic mode.
  22  *
  23  * Returns 0 on success, < 0 on failure while setting *errp.
  24  */
  25 int qemu_guest_random_seed_main(const char *seedstr, Error **errp);
  26
  27 /**
  28  * qemu_guest_random_seed_thread_part1(void)
  29  *
  30  * If qemu_getrandom is in deterministic mode, returns an
  31  * independent seed for the new thread.  Otherwise returns 0.
  32  */
  33 uint64_t qemu_guest_random_seed_thread_part1(void);
  34
  35 /**
  36  * qemu_guest_random_seed_thread_part2(uint64_t seed)
  37  * @seed: a value for the new thread.
  38  *
  39  * If qemu_guest_getrandom is in deterministic mode, this stores an
  40  * independent seed for the new thread.  Otherwise a no-op.
  41  */
  42 void qemu_guest_random_seed_thread_part2(uint64_t seed);
  43
  44 /**
  45  * qemu_guest_getrandom(void *buf, size_t len, Error **errp)
  46  * @buf: a buffer of bytes to be written
  47  * @len: the number of bytes in @buf
  48  * @errp: an error indicator
  49  *
  50  * Fills len bytes in buf with random data.  This should only be used
  51  * for data presented to the guest.  Host-side crypto services should
  52  * use qcrypto_random_bytes.
  53  *
  54  * Returns 0 on success, < 0 on failure while setting *errp.
  55  */
  56 int qemu_guest_getrandom(void *buf, size_t len, Error **errp);
  57
  58 /**
  59  * qemu_guest_getrandom_nofail(void *buf, size_t len)
  60  * @buf: a buffer of bytes to be written
  61  * @len: the number of bytes in @buf
  62  *
  63  * Like qemu_guest_getrandom, but will assert for failure.
  64  * Use this when there is no reasonable recovery.
  65  */
  66 void qemu_guest_getrandom_nofail(void *buf, size_t len);
  67
  68 #endif /* QEMU_GUEST_RANDOM_H */