Update ExecUtils to support artd use cases.

- Use pidfd_open/poll instaed of sigprocmask/sigtimedwait to implement
  executing a command with a timeout because sigprocmask/sigtimedwait
  does not support multithreaded program, while artd is multithreaded.
  The same approach is used in installd in
  https://r.android.com/1993670.
- Add "const" to the `std::vector<std::string>& arg_vector` parameter.
- Use "int" instead of "time_t" for the "timeout_sec" parameter because
  "time_t" represents the time since epoch rather than a duration.
- Set an error message with the signal number when the subprocess is
  terminated by a signal.
- Crash the subprocess instead of exiting it with an exit code when
  execv fails.

The behavior does not change. ExecUtilsTest is still passing.

Bug: 229268202
Test: m test-art-host-gtest-art_runtime_tests
Test: atest ArtGtestsTargetChroot:ExecUtilsTest
Change-Id: I375034162cded6fdf09ee4d4cd783a0d3987af49
Merged-In: I375034162cded6fdf09ee4d4cd783a0d3987af49
(cherry picked from commit b48b732c535894bbae8f3c19eceeda67c40e9d61)

1 files changed, 37 insertions, 3 deletions

diff --git a/runtime/exec_utils_test.cc b/runtime/exec_utils_test.cc
index dc789aa292..aa53739cfa 100644
--- a/runtime/exec_utils_test.cc
+++ b/runtime/exec_utils_test.cc
@@ -16,16 +16,34 @@
 
 #include "exec_utils.h"
 
+#include <unistd.h>
+
 #include "android-base/stringprintf.h"
 #include "base/file_utils.h"
 #include "base/memory_tool.h"
 #include "common_runtime_test.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
 
 namespace art {
 
 std::string PrettyArguments(const char* signature);
 std::string PrettyReturnType(const char* signature);
 
+bool IsPidfdSupported() {
+#ifdef __BIONIC__
+  return true;
+#else
+  constexpr int SYS_pidfd_open = 434;
+  int pidfd = syscall(SYS_pidfd_open, getpid(), /*flags=*/0);
+  if (pidfd < 0) {
+    return false;
+  }
+  close(pidfd);
+  return true;
+#endif
+}
+
 class ExecUtilsTest : public CommonRuntimeTest {};
 
 TEST_F(ExecUtilsTest, ExecSuccess) {
@@ -44,9 +62,6 @@ TEST_F(ExecUtilsTest, ExecSuccess) {
 }
 
 TEST_F(ExecUtilsTest, ExecError) {
-  // This will lead to error messages in the log.
-  ScopedLogSeverity sls(LogSeverity::FATAL);
-
   std::vector<std::string> command;
   command.push_back("bogus");
   std::string error_msg;
@@ -115,6 +130,10 @@ static std::vector<std::string> SleepCommand(int sleep_seconds) {
 }
 
 TEST_F(ExecUtilsTest, ExecTimeout) {
+  if (!IsPidfdSupported()) {
+    GTEST_SKIP() << "pidfd not supported";
+  }
+
   static constexpr int kSleepSeconds = 5;
   static constexpr int kWaitSeconds = 1;
   std::vector<std::string> command = SleepCommand(kSleepSeconds);
@@ -125,6 +144,10 @@ TEST_F(ExecUtilsTest, ExecTimeout) {
 }
 
 TEST_F(ExecUtilsTest, ExecNoTimeout) {
+  if (!IsPidfdSupported()) {
+    GTEST_SKIP() << "pidfd not supported";
+  }
+
   static constexpr int kSleepSeconds = 1;
   static constexpr int kWaitSeconds = 5;
   std::vector<std::string> command = SleepCommand(kSleepSeconds);
@@ -134,4 +157,15 @@ TEST_F(ExecUtilsTest, ExecNoTimeout) {
   EXPECT_FALSE(timed_out);
 }
 
+TEST_F(ExecUtilsTest, ExecTimeoutNotSupported) {
+  if (IsPidfdSupported()) {
+    GTEST_SKIP() << "pidfd supported";
+  }
+
+  std::string error_msg;
+  bool timed_out;
+  ASSERT_EQ(ExecAndReturnCode({"command"}, /*timeout_sec=*/0, &timed_out, &error_msg), -1);
+  EXPECT_THAT(error_msg, testing::HasSubstr("pidfd_open failed for pid"));
+}
+
 }  // namespace art