crypto: Reverse code blocks in random-platform.c

Use #ifdef _WIN32 instead of #ifndef _WIN32.
This will make other tests easier to sequence.
Reviewed-by: NLaurent Vivier <lvivier@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>

crypto/random-platform.c

@@ -32,7 +32,14 @@ static int fd; /* a file handle to either /dev/urandom or /dev/random */
 
 int qcrypto_random_init(Error **errp)
 {
-#ifndef _WIN32
+#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
     /* TBD perhaps also add support for BSD getentropy / Linux
      * getrandom syscalls directly */
     fd = open("/dev/urandom", O_RDONLY);
@@ -44,15 +51,7 @@ int qcrypto_random_init(Error **errp)
         error_setg(errp, "No /dev/urandom or /dev/random found");
         return -1;
     }
-#else
-    if (!CryptAcquireContext(&hCryptProv, NULL, NULL, PROV_RSA_FULL,
-                             CRYPT_SILENT | CRYPT_VERIFYCONTEXT)) {
-        error_setg_win32(errp, GetLastError(),
-                         "Unable to create cryptographic provider");
-        return -1;
-    }
 #endif
-
     return 0;
 }
 
@@ -60,7 +59,15 @@ int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
                          size_t buflen G_GNUC_UNUSED,
                          Error **errp)
 {
-#ifndef _WIN32
+#ifdef _WIN32
+    if (!CryptGenRandom(hCryptProv, buflen, buf)) {
+        error_setg_win32(errp, GetLastError(),
+                         "Unable to read random bytes");
+        return -1;
+    }
+
+    return 0;
+#else
     int ret = -1;
     int got;
 
@@ -82,13 +89,5 @@ int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
     ret = 0;
  cleanup:
     return ret;
-#else
-    if (!CryptGenRandom(hCryptProv, buflen, buf)) {
-        error_setg_win32(errp, GetLastError(),
-                         "Unable to read random bytes");
-        return -1;
-    }
-
-    return 0;
 #endif
 }