Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 114 insertions, 0 deletions

diff --git a/crypto/random-platform.c b/crypto/random-platform.c
new file mode 100644
index 000000000..f92f96987
--- /dev/null
+++ b/crypto/random-platform.c
@@ -0,0 +1,114 @@
+/*
+ * QEMU Crypto random number provider
+ *
+ * Copyright (c) 2015-2016 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "qemu/osdep.h"
+
+#include "crypto/random.h"
+#include "qapi/error.h"
+
+#ifdef _WIN32
+#include <wincrypt.h>
+static HCRYPTPROV hCryptProv;
+#else
+# ifdef CONFIG_GETRANDOM
+#  include <sys/random.h>
+# endif
+/* This is -1 for getrandom(), or a file handle for /dev/{u,}random.  */
+static int fd;
+#endif
+
+int qcrypto_random_init(Error **errp)
+{
+#ifdef _WIN32
+    if (!CryptAcquireContext(&hCryptProv, NULL, NULL, PROV_RSA_FULL,
+                             CRYPT_SILENT | CRYPT_VERIFYCONTEXT)) {
+        error_setg_win32(errp, GetLastError(),
+                         "Unable to create cryptographic provider");
+        return -1;
+    }
+#else
+# ifdef CONFIG_GETRANDOM
+    if (getrandom(NULL, 0, 0) == 0) {
+        /* Use getrandom() */
+        fd = -1;
+        return 0;
+    }
+    /* Fall through to /dev/urandom case.  */
+# endif
+    fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
+    if (fd == -1 && errno == ENOENT) {
+        fd = open("/dev/random", O_RDONLY | O_CLOEXEC);
+    }
+    if (fd < 0) {
+        error_setg_errno(errp, errno, "No /dev/urandom or /dev/random");
+        return -1;
+    }
+#endif
+    return 0;
+}
+
+int qcrypto_random_bytes(void *buf,
+                         size_t buflen,
+                         Error **errp)
+{
+#ifdef _WIN32
+    if (!CryptGenRandom(hCryptProv, buflen, buf)) {
+        error_setg_win32(errp, GetLastError(),
+                         "Unable to read random bytes");
+        return -1;
+    }
+#else
+# ifdef CONFIG_GETRANDOM
+    if (likely(fd < 0)) {
+        while (1) {
+            ssize_t got = getrandom(buf, buflen, 0);
+            if (likely(got == buflen)) {
+                return 0;
+            }
+            if (got >= 0) {
+                buflen -= got;
+                buf += got;
+            } else if (errno != EINTR) {
+                error_setg_errno(errp, errno, "getrandom");
+                return -1;
+            }
+        }
+    }
+    /* Fall through to /dev/urandom case.  */
+# endif
+    while (1) {
+        ssize_t got = read(fd, buf, buflen);
+        if (likely(got == buflen)) {
+            return 0;
+        }
+        if (got > 0) {
+            buflen -= got;
+            buf += got;
+        } else if (got == 0) {
+            error_setg(errp, "Unexpected EOF reading random bytes");
+            return -1;
+        } else if (errno != EINTR) {
+            error_setg_errno(errp, errno, "Unable to read random bytes");
+            return -1;
+        }
+    }
+#endif
+    return 0;
+}