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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include <vespa/vespalib/util/memory_trap.h>
#include <vespa/vespalib/gtest/gtest.h>
#include <cstdlib>
using namespace vespalib;
using namespace ::testing;
template <typename T>
void do_not_optimize_away(T&& t) noexcept {
asm volatile("" : : "m"(t) : "memory"); // Clobber the value to avoid losing it to compiler optimizations
}
struct MemoryTrapTest : Test {
static void SetUpTestSuite() {
// Don't overwrite env var if already set; we'll assume it's done for a good reason.
setenv("VESPA_USE_MPROTECT_TRAP", "true", 0);
}
};
TEST_F(MemoryTrapTest, untouched_memory_traps_do_not_trigger) {
InlineMemoryTrap<2> stack_trap;
HeapMemoryTrap heap_trap(4);
// No touching == no crashing. Good times.
}
TEST_F(MemoryTrapTest, write_to_stack_trap_eventually_discovered) {
// We don't explicitly test death messages since the way the process dies depends on
// whether mprotect is enabled, whether ASAN instrumentation is enabled etc.
ASSERT_DEATH({
InlineMemoryTrap<2> stack_trap;
// This may trigger immediately or on destruction. Either way it eventually kills the process.
stack_trap.trapper().buffer()[0] = 0x01;
},"");
}
TEST_F(MemoryTrapTest, write_to_heap_trap_eventually_discovered) {
ASSERT_DEATH({
HeapMemoryTrap heap_trap(4);
// This may trigger immediately or on destruction. Either way it eventually kills the process.
heap_trap.trapper().buffer()[heap_trap.trapper().size() - 1] = 0x01;
},"");
}
TEST_F(MemoryTrapTest, read_from_hw_backed_trap_crashes_process) {
if (!MemoryRangeTrapper::hw_trapping_enabled()) {
return;
}
ASSERT_DEATH({
HeapMemoryTrap heap_trap(4); // Entire buffer should always be covered
// Clobber trap just in case the compiler is clever enough to look into the trap implementation
// and see that we memset everything to zero and `dummy` can thus be constant-promoted to 0
// (probably won't dare to do this anyway due to opaque mprotect() that touches buffer pointer).
do_not_optimize_away(heap_trap);
char dummy = heap_trap.trapper().buffer()[0];
do_not_optimize_away(dummy); // never reached
},"");
}
GTEST_MAIN_RUN_ALL_TESTS()
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