[lldb] Fix the SocketTest failure on unsupported hosts

[ashgti]

The test SocketTest::TCPListen0MultiListenerGetListeningConnectionURI is failing on hosts that do not map localhost to both an ipv4 and ipv6 address. For example this build https://lab.llvm.org/buildbot/#/builders/195/builds/1909.

To fix this, I added a helper to validate if the host has an /etc/hosts entry for both ipv4 and ipv6, otherwise we skip the test.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: John Harrison (ashgti)

Changes

The test SocketTest::TCPListen0MultiListenerGetListeningConnectionURI is failing on hosts that do not map localhost to both an ipv4 and ipv6 address. For example this build https://lab.llvm.org/buildbot/#/builders/195/builds/1909.

To fix this, I added a helper to validate if the host has an /etc/hosts entry for both ipv4 and ipv6, otherwise we skip the test.

---

Full diff: https://github.com/llvm/llvm-project/pull/118673.diff

3 Files Affected:

• (modified) lldb/unittests/Host/SocketTest.cpp (+1-1)
• (modified) lldb/unittests/TestingSupport/Host/SocketTestUtilities.cpp (+18)
• (modified) lldb/unittests/TestingSupport/Host/SocketTestUtilities.h (+5)

diff --git a/lldb/unittests/Host/SocketTest.cpp b/lldb/unittests/Host/SocketTest.cpp
index 689ef4019c618c..9cbf3e26b0883f 100644
--- a/lldb/unittests/Host/SocketTest.cpp
+++ b/lldb/unittests/Host/SocketTest.cpp
@@ -271,7 +271,7 @@ TEST_P(SocketTest, TCPListen0GetListeningConnectionURI) {
 }
 
 TEST_F(SocketTest, TCPListen0MultiListenerGetListeningConnectionURI) {
-  if (!HostSupportsIPv6() || !HostSupportsIPv4())
+  if (!HostSupportsLocalhostToIPv4() || !HostSupportsLocalhostToIPv6())
     return;
 
   llvm::Expected<std::unique_ptr<TCPSocket>> sock =
diff --git a/lldb/unittests/TestingSupport/Host/SocketTestUtilities.cpp b/lldb/unittests/TestingSupport/Host/SocketTestUtilities.cpp
index eb5bda0fabc770..86349351b0c3a4 100644
--- a/lldb/unittests/TestingSupport/Host/SocketTestUtilities.cpp
+++ b/lldb/unittests/TestingSupport/Host/SocketTestUtilities.cpp
@@ -116,6 +116,24 @@ bool lldb_private::HostSupportsIPv6() {
   return CheckIPSupport("IPv6", "[::1]:0");
 }
 
+bool lldb_private::HostSupportsLocalhostToIPv4() {
+  if (!HostSupportsIPv4())
+    return false;
+
+  auto addresses = SocketAddress::GetAddressInfo("localhost", nullptr, AF_INET,
+                                                 SOCK_STREAM, IPPROTO_TCP);
+  return !addresses.empty();
+}
+
+bool lldb_private::HostSupportsLocalhostToIPv6() {
+  if (!HostSupportsIPv6())
+    return false;
+
+  auto addresses = SocketAddress::GetAddressInfo("localhost", nullptr, AF_INET6,
+                                                 SOCK_STREAM, IPPROTO_TCP);
+  return !addresses.empty();
+}
+
 llvm::Expected<std::string> lldb_private::GetLocalhostIP() {
   if (HostSupportsIPv4())
     return "127.0.0.1";
diff --git a/lldb/unittests/TestingSupport/Host/SocketTestUtilities.h b/lldb/unittests/TestingSupport/Host/SocketTestUtilities.h
index efd17428ceefb6..e5bab163cf82eb 100644
--- a/lldb/unittests/TestingSupport/Host/SocketTestUtilities.h
+++ b/lldb/unittests/TestingSupport/Host/SocketTestUtilities.h
@@ -43,6 +43,11 @@ void CreateDomainConnectedSockets(llvm::StringRef path,
 bool HostSupportsIPv6();
 bool HostSupportsIPv4();
 
+/// Returns true if the name `localhost` maps to a loopback IPv4 address.
+bool HostSupportsLocalhostToIPv4();
+/// Returns true if the name `localhost` maps to a loopback IPv6 address.
+bool HostSupportsLocalhostToIPv6();
+
 /// Return an IP for localhost based on host support.
 ///
 /// This will return either "127.0.0.1" if IPv4 is detected, or "[::1]" if IPv6

[dzhidzhoev]

Hmm, on my machine it fails with the same error after the commit is applied

Script:
--
/home/parallels/llvm-build-release/tools/lldb/unittests/Host/./HostTests --gtest_filter=SocketTest.TCPListen0MultiListenerGetListeningConnectionURI
--
/home/parallels/llvm-project/lldb/unittests/Host/SocketTest.cpp:289: Failure
Value of: sock.get()->GetListeningConnectionURI()
Expected: has 2 elements and there exists some permutation of elements such that:
 - element #0 is equal to "connection://[::1]:35725", and
 - element #1 is equal to "connection://[127.0.0.1]:35725"
  Actual: { "connection://[127.0.0.1]:35725" }, which has 1 element


/home/parallels/llvm-project/lldb/unittests/Host/SocketTest.cpp:289
Value of: sock.get()->GetListeningConnectionURI()
Expected: has 2 elements and there exists some permutation of elements such that:
 - element #0 is equal to "connection://[::1]:35725", and
 - element #1 is equal to "connection://[127.0.0.1]:35725"
  Actual: { "connection://[127.0.0.1]:35725" }, which has 1 element

[dzhidzhoev]

I've got

llvm-project git:(becab1c1b0a3) cat /etc/hosts     
127.0.0.1 localhost
127.0.1.1 ubuntu-linux-22-04-desktop

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

For some reason, getaddrinfo("localhost", AF_UNSPEC, ...) returns only one address (IPv4 127.0.0.1), but getaddrinfo("localhost", AF_INET6, ...) returns an address as well (IPv6 ::1).

I think it's probably an oddity in getaddrinfo implementation (my gai.conf is empty). This check seems to work the way expected:

auto addresses = SocketAddress::GetAddressInfo(
    "localhost", nullptr, AF_UNSPEC, SOCK_STREAM, IPPROTO_TCP);
return std::find_if(addresses.begin(), addresses.end(),
                    [](SocketAddress &addr) {
                      return addr.GetFamily() == AF_INET6;
                    }) != addresses.end();

[ashgti]

Thanks for the suggestion!

I tried this on my mac by commenting out the ::1 localhost line in my hosts file, but I wonder if I had some caching or something happening.

Applied this suggestion.

[labath]

Just a small llvm-ization:

return llvm::any_of(addresses, [](const SocketAddress &addr) { return addr.GetFamily() == AF_INET; });