ucontext_t support for Android x86.

sandbox/linux/services/ucontext_unittest.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <setjmp.h>
+#include <signal.h>
+#include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
+#include "sandbox/linux/services/android_ucontext.h"
+#include "sandbox/linux/tests/unit_tests.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace sandbox {
+const int kExpectedValueParm2 = 0xec;
+const int kExpectedValueParm3 = 0xed;
+const int kExpectedValueParm4 = 0xee;
+const int kExpectedValueParm5 = 0x00;
+
+void SigAction(int n, siginfo_t *SigInfo, void* SigContext) {
+  const ucontext_t *Context = static_cast<ucontext_t*>(SigContext);
+  sigset_t set = 0;
+
+  sigaddset(&set, SIGPIPE);
+  sigaddset(&set, SIGFPE);
+
+  // ARM define registers array as unsigned while x86 define it as signed.
+  SANDBOX_ASSERT(static_cast<int>(SECCOMP_PARM2(Context)) ==
+                 static_cast<int>(kExpectedValueParm2));
+  SANDBOX_ASSERT(static_cast<int>(SECCOMP_PARM3(Context)) ==
+                 static_cast<int>(kExpectedValueParm3));
+  SANDBOX_ASSERT(static_cast<int>(SECCOMP_PARM4(Context)) ==
+                 static_cast<int>(kExpectedValueParm4));
+  SANDBOX_ASSERT(static_cast<int>(SECCOMP_PARM5(Context)) ==
+                 static_cast<int>(kExpectedValueParm5));
+  SANDBOX_ASSERT(Context->uc_sigmask == set);
+}
+
+SANDBOX_DEATH_TEST(UcontextTest, TestUcontext, DEATH_BY_SIGNAL(SIGSEGV)) {
+  int ret;
+  struct sigaction NewAct;
+  struct sigaction OldAct;
+  sigset_t NewSet, OldSet;
+
+  memset(&NewAct, 0, sizeof(NewAct));
+  NewAct.sa_sigaction = SigAction;
+  // We need SA_RESETHAND here to make sure the process is terminated
+  // after return from signal handler. Otherwise, there will be dead loop.
+  NewAct.sa_flags = SA_RESETHAND | SA_SIGINFO;
+  sigemptyset(&NewAct.sa_mask);
+
+  sigemptyset(&NewSet);
+  sigaddset(&NewSet, SIGPIPE);
+  sigaddset(&NewSet, SIGFPE);
+
+  sigprocmask(SIG_SETMASK, &NewSet, &OldSet);
+  ret = sigaction(SIGSEGV, &NewAct, &OldAct);
+  SANDBOX_ASSERT(ret == 0);
+
+  // We don't use *((int*) 0x0) = 0xdeadbeaf here because toolchain
+  // may allocate registers (Android ARM gcc uses r2/r3). Which makes
+  // registers checked in signal handler are not easy to choice.
+  // The following code is suppose to make process terminated. So we don't
+  // care about the which reigsters are clobbered here.
+#if defined(__i386__)
+    asm __volatile__ (
+      "movl $0xec, %ecx\n\t"
+      "movl $0xed, %edx\n\t"
+      "movl $0xee, %esi\n\t"
+      "movl $0x00, %edi\n\t"
+      "movl $0x00, (%edi)\n\t"
+      );
+#elif defined(__arm__)
+    asm __volatile__ (
+      "mov r1, #0xec\n\t"
+      "mov r2, #0xed\n\t"
+      "mov r3, #0xee\n\t"
+      "mov r4, #0x00\n\t"
+      "str r3, [r4]\n\t"
+    );
+#endif
+
+  /* Shouldn't be here */
+  SANDBOX_ASSERT(1 == 0);
+  sigprocmask(SIG_SETMASK, &OldSet, NULL);
+  sigaction(SIGSEGV, &OldAct, NULL);
+}
+
+}  // namespace sandbox