libc/test/src/signal/sigaltstack_test.cpp

   1 //===-- Unittests for sigaltstack -----------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "hdr/signal_macros.h"
  10 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
  11 #include "src/errno/libc_errno.h"
  12 #include "src/signal/linux/signal_utils.h"
  13 #include "src/signal/raise.h"
  14 #include "src/signal/sigaction.h"
  15 #include "src/signal/sigaltstack.h"
  16 #include "test/UnitTest/ErrnoSetterMatcher.h"
  17 #include "test/UnitTest/Test.h"
  18
  19 #include <stdint.h>
  20 #include <sys/syscall.h>
  21
  22 constexpr int LOCAL_VAR_SIZE = 512;
  23 constexpr int ALT_STACK_SIZE = SIGSTKSZ + LOCAL_VAR_SIZE * 2;
  24 static uint8_t alt_stack[ALT_STACK_SIZE];
  25
  26 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
  27 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
  28
  29 static bool good_stack;
  30 static void handler(int) {
  31   // Allocate a large stack variable so that it does not get optimized
  32   // out or mapped to a register.
  33   uint8_t var[LOCAL_VAR_SIZE];
  34   for (int i = 0; i < LOCAL_VAR_SIZE; ++i)
  35     var[i] = i;
  36   // Verify that array is completely on the alt_stack.
  37   for (int i = 0; i < LOCAL_VAR_SIZE; ++i) {
  38     if (!(uintptr_t(var + i) < uintptr_t(alt_stack + ALT_STACK_SIZE) &&
  39           uintptr_t(alt_stack) <= uintptr_t(var + i))) {
  40       good_stack = false;
  41       return;
  42     }
  43   }
  44   good_stack = true;
  45 }
  46
  47 TEST(LlvmLibcSignalTest, SigaltstackRunOnAltStack) {
  48   struct sigaction action;
  49   LIBC_NAMESPACE::libc_errno = 0;
  50   ASSERT_THAT(LIBC_NAMESPACE::sigaction(SIGUSR1, nullptr, &action),
  51               Succeeds(0));
  52   action.sa_handler = handler;
  53   // Indicate that the signal should be delivered on an alternate stack.
  54   action.sa_flags = SA_ONSTACK;
  55   ASSERT_THAT(LIBC_NAMESPACE::sigaction(SIGUSR1, &action, nullptr),
  56               Succeeds(0));
  57
  58   stack_t ss;
  59   ss.ss_sp = alt_stack;
  60   ss.ss_size = ALT_STACK_SIZE;
  61   ss.ss_flags = 0;
  62   // Setup the alternate stack.
  63   ASSERT_THAT(LIBC_NAMESPACE::sigaltstack(&ss, nullptr), Succeeds(0));
  64
  65   good_stack = false;
  66   LIBC_NAMESPACE::raise(SIGUSR1);
  67   EXPECT_TRUE(good_stack);
  68 }
  69
  70 // This tests for invalid input.
  71 TEST(LlvmLibcSignalTest, SigaltstackInvalidStack) {
  72   stack_t ss;
  73   ss.ss_sp = alt_stack;
  74   ss.ss_size = 0;
  75   ss.ss_flags = SS_ONSTACK;
  76   ASSERT_THAT(LIBC_NAMESPACE::sigaltstack(&ss, nullptr), Fails(EINVAL));
  77
  78   ss.ss_flags = 0;
  79   ASSERT_THAT(LIBC_NAMESPACE::sigaltstack(&ss, nullptr), Fails(ENOMEM));
  80 }