Remove flaky network namespace test that uses clone().

PiperOrigin-RevId: 300626011

test/syscalls/linux/BUILD

@@ -3707,11 +3707,10 @@ cc_binary(
         ":socket_test_util",
         gtest,
         "//test/util:capability_util",
-        "//test/util:memory_util",
+        "//test/util:posix_error",
         "//test/util:test_main",
         "//test/util:test_util",
         "//test/util:thread_util",
-        "@com_google_absl//absl/synchronization",
     ],
 )
 

test/syscalls/linux/network_namespace.cc

@@ -20,102 +20,33 @@
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
-#include "absl/synchronization/notification.h"
 #include "test/syscalls/linux/socket_test_util.h"
 #include "test/util/capability_util.h"
-#include "test/util/memory_util.h"
+#include "test/util/posix_error.h"
 #include "test/util/test_util.h"
 #include "test/util/thread_util.h"
 
 namespace gvisor {
 namespace testing {
-
 namespace {
 
-using TestFunc = std::function<PosixError()>;
-using RunFunc = std::function<PosixError(TestFunc)>;
-
-struct NamespaceStrategy {
-  RunFunc run;
-
-  static NamespaceStrategy Of(RunFunc run) {
-    NamespaceStrategy s;
-    s.run = run;
-    return s;
-  }
-};
-
-PosixError RunWithUnshare(TestFunc fn) {
-  PosixError err = PosixError(-1, "function did not return a value");
-  ScopedThread t([&] {
-    if (unshare(CLONE_NEWNET) != 0) {
-      err = PosixError(errno);
-      return;
-    }
-    err = fn();
-  });
-  t.Join();
-  return err;
-}
-
-PosixError RunWithClone(TestFunc fn) {
-  struct Args {
-    absl::Notification n;
-    TestFunc fn;
-    PosixError err;
-  };
-  Args args;
-  args.fn = fn;
-  args.err = PosixError(-1, "function did not return a value");
-
-  ASSIGN_OR_RETURN_ERRNO(
-      Mapping child_stack,
-      MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
-  pid_t child = clone(
-      +[](void *arg) {
-        Args *args = reinterpret_cast<Args *>(arg);
-        args->err = args->fn();
-        args->n.Notify();
-        syscall(SYS_exit, 0);  // Exit manually. No return address on stack.
-        return 0;
-      },
-      reinterpret_cast<void *>(child_stack.addr() + kPageSize),
-      CLONE_NEWNET | CLONE_THREAD | CLONE_SIGHAND | CLONE_VM, &args);
-  if (child < 0) {
-    return PosixError(errno, "clone() failed");
-  }
-  args.n.WaitForNotification();
-  return args.err;
-}
-
-class NetworkNamespaceTest
-    : public ::testing::TestWithParam<NamespaceStrategy> {};
-
-TEST_P(NetworkNamespaceTest, LoopbackExists) {
+TEST(NetworkNamespaceTest, LoopbackExists) {
   SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_ADMIN)));
 
-  EXPECT_NO_ERRNO(GetParam().run([]() {
+  ScopedThread t([&] {
+    ASSERT_THAT(unshare(CLONE_NEWNET), SyscallSucceedsWithValue(0));
+
     // TODO(gvisor.dev/issue/1833): Update this to test that only "lo" exists.
     // Check loopback device exists.
     int sock = socket(AF_INET, SOCK_DGRAM, 0);
-    if (sock < 0) {
-      return PosixError(errno, "socket() failed");
-    }
+    ASSERT_THAT(sock, SyscallSucceeds());
     struct ifreq ifr;
-    snprintf(ifr.ifr_name, IFNAMSIZ, "lo");
-    if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0) {
-      return PosixError(errno, "ioctl() failed, lo cannot be found");
-    }
-    return NoError();
-  }));
+    strncpy(ifr.ifr_name, "lo", IFNAMSIZ);
+    EXPECT_THAT(ioctl(sock, SIOCGIFINDEX, &ifr), SyscallSucceeds())
+        << "lo cannot be found";
+  });
 }
 
-INSTANTIATE_TEST_SUITE_P(
-    AllNetworkNamespaceTest, NetworkNamespaceTest,
-    ::testing::Values(NamespaceStrategy::Of(RunWithUnshare),
-                      NamespaceStrategy::Of(RunWithClone)));
-
 }  // namespace
-
 }  // namespace testing
 }  // namespace gvisor