// Copyright 2018 The gVisor Authors. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. #include <sys/syscall.h> #include <sys/types.h> #include <unistd.h> #include "gtest/gtest.h" #include "test/util/test_util.h" namespace gvisor { namespace testing { namespace { #ifndef SYS_getrandom #if defined(__x86_64__) #define SYS_getrandom 318 #elif defined(__i386__) #define SYS_getrandom 355 #elif defined(__aarch64__) #define SYS_getrandom 278 #else #error "Unknown architecture" #endif #endif // SYS_getrandom bool SomeByteIsNonZero(char* random_bytes, int length) { for (int i = 0; i < length; i++) { if (random_bytes[i] != 0) { return true; } } return false; } TEST(GetrandomTest, IsRandom) { // This test calls get_random and makes sure that the array is filled in with // something that is non-zero. Perhaps we get back \x00\x00\x00\x00\x00.... as // a random result, but it's so unlikely that we'll just ignore this. char random_bytes[64] = {}; int n = syscall(SYS_getrandom, random_bytes, 64, 0); SKIP_IF(!IsRunningOnGvisor() && n < 0 && errno == ENOSYS); EXPECT_THAT(n, SyscallSucceeds()); EXPECT_GT(n, 0); // Some bytes should be returned. EXPECT_TRUE(SomeByteIsNonZero(random_bytes, n)); } } // namespace } // namespace testing } // namespace gvisor