crypto: qcrypto_random_bytes() now works on windows w/o any other crypto libs

If no crypto library is included in the build, QEMU uses
qcrypto_random_bytes() to generate random data. That function tried to open
/dev/urandom or /dev/random and if opening both files failed it errored out.

Those files obviously do not exist on windows, so there the code uses
CryptGenRandom().

Furthermore there was some refactoring and a new function
qcrypto_random_init() was introduced. If a proper crypto library (gnutls or
libgcrypt) is included in the build, this function does nothing. If neither
is included it initializes the (platform specific) handles that are used by
qcrypto_random_bytes().
Either:
* a handle to /dev/urandom | /dev/random on unix like systems
* a handle to a cryptographic service provider on windows

Signed-off-by: Geert Martin Ijewski <gm.ijewski@web.de>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/crypto/random-gcrypt.c b/crypto/random-gcrypt.c
index 0de9a096df..9f1c9ee60e 100644
--- a/crypto/random-gcrypt.c
+++ b/crypto/random-gcrypt.c
@@ -31,3 +31,5 @@ int qcrypto_random_bytes(uint8_t *buf,
     gcry_randomize(buf, buflen, GCRY_STRONG_RANDOM);
     return 0;
 }
+
+int qcrypto_random_init(Error **errp G_GNUC_UNUSED) { return 0; }