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author | Richard Henderson <richard.henderson@linaro.org> | 2019-03-14 13:02:09 -0700 |
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committer | Richard Henderson <richard.henderson@linaro.org> | 2019-05-22 12:38:54 -0400 |
commit | 8d8404f1564496f42b90497e7be635921c000e9d (patch) | |
tree | 0b25ec7d6d4454fc5218ac5684acfa70bdd7140e /include/qemu/guest-random.h | |
parent | f7b2502cdc2eeb458a4490c1b8f4a83c07d46219 (diff) | |
download | qemu-8d8404f1564496f42b90497e7be635921c000e9d.zip qemu-8d8404f1564496f42b90497e7be635921c000e9d.tar.gz qemu-8d8404f1564496f42b90497e7be635921c000e9d.tar.bz2 |
util: Add qemu_guest_getrandom and associated routines
This routine is intended to produce high-quality random numbers to the
guest. Normally, such numbers are crypto quality from the host, but a
command-line option can force the use of a fully deterministic sequence
for use while debugging.
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'include/qemu/guest-random.h')
-rw-r--r-- | include/qemu/guest-random.h | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/include/qemu/guest-random.h b/include/qemu/guest-random.h new file mode 100644 index 0000000..09ff9c2 --- /dev/null +++ b/include/qemu/guest-random.h @@ -0,0 +1,68 @@ +/* + * QEMU guest-visible random functions + * + * Copyright 2019 Linaro, Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + */ + +#ifndef QEMU_GUEST_RANDOM_H +#define QEMU_GUEST_RANDOM_H + +/** + * qemu_guest_random_seed_main(const char *optarg, Error **errp) + * @optarg: a non-NULL pointer to a C string + * @errp: an error indicator + * + * The @optarg value is that which accompanies the -seed argument. + * This forces qemu_guest_getrandom into deterministic mode. + * + * Returns 0 on success, < 0 on failure while setting *errp. + */ +int qemu_guest_random_seed_main(const char *optarg, Error **errp); + +/** + * qemu_guest_random_seed_thread_part1(void) + * + * If qemu_getrandom is in deterministic mode, returns an + * independent seed for the new thread. Otherwise returns 0. + */ +uint64_t qemu_guest_random_seed_thread_part1(void); + +/** + * qemu_guest_random_seed_thread_part2(uint64_t seed) + * @seed: a value for the new thread. + * + * If qemu_guest_getrandom is in deterministic mode, this stores an + * independent seed for the new thread. Otherwise a no-op. + */ +void qemu_guest_random_seed_thread_part2(uint64_t seed); + +/** + * qemu_guest_getrandom(void *buf, size_t len, Error **errp) + * @buf: a buffer of bytes to be written + * @len: the number of bytes in @buf + * @errp: an error indicator + * + * Fills len bytes in buf with random data. This should only be used + * for data presented to the guest. Host-side crypto services should + * use qcrypto_random_bytes. + * + * Returns 0 on success, < 0 on failure while setting *errp. + */ +int qemu_guest_getrandom(void *buf, size_t len, Error **errp); + +/** + * qemu_guest_getrandom_nofail(void *buf, size_t len) + * @buf: a buffer of bytes to be written + * @len: the number of bytes in @buf + * + * Like qemu_guest_getrandom, but will assert for failure. + * Use this when there is no reasonable recovery. + */ +void qemu_guest_getrandom_nofail(void *buf, size_t len); + +#endif /* QEMU_GUEST_RANDOM_H */ |