From 5685eb950da7c6901c8b264a3c93e8ea63b34d3d Mon Sep 17 00:00:00 2001
From: Pavel Labath <pavel@labath.sk>
Date: Thu, 23 Sep 2021 11:31:33 +0200
Subject: [PATCH] [lldb] Fix DomainSocket::GetSocketName for unnamed sockets

getpeername will return addrlen = 2 (sizeof sa_family_t) for unnamed
sockets (those not assigned a name with bind(2)). This is typically true
for client sockets as well as those created by socketpair(2).

This GetSocketName used to crash for sockets which were connected to
these kinds of sockets. Now it returns an empty string.
---
 lldb/source/Host/posix/DomainSocket.cpp | 47 ++++++++++++++-----------
 lldb/unittests/Host/SocketTest.cpp      |  2 ++
 2 files changed, 28 insertions(+), 21 deletions(-)

diff --git a/lldb/source/Host/posix/DomainSocket.cpp b/lldb/source/Host/posix/DomainSocket.cpp
index 7322b15200b4..790458ee13d0 100644
--- a/lldb/source/Host/posix/DomainSocket.cpp
+++ b/lldb/source/Host/posix/DomainSocket.cpp
@@ -127,29 +127,34 @@ void DomainSocket::DeleteSocketFile(llvm::StringRef name) {
 }
 
 std::string DomainSocket::GetSocketName() const {
-  if (m_socket != kInvalidSocketValue) {
-    struct sockaddr_un saddr_un;
-    saddr_un.sun_family = AF_UNIX;
-    socklen_t sock_addr_len = sizeof(struct sockaddr_un);
-    if (::getpeername(m_socket, (struct sockaddr *)&saddr_un, &sock_addr_len) ==
-        0) {
-      std::string name(saddr_un.sun_path + GetNameOffset(),
-                       sock_addr_len -
-                           offsetof(struct sockaddr_un, sun_path) -
+  if (m_socket == kInvalidSocketValue)
+    return "";
+
+  struct sockaddr_un saddr_un;
+  saddr_un.sun_family = AF_UNIX;
+  socklen_t sock_addr_len = sizeof(struct sockaddr_un);
+  if (::getpeername(m_socket, (struct sockaddr *)&saddr_un, &sock_addr_len) !=
+      0)
+    return "";
+
+  if (sock_addr_len <= offsetof(struct sockaddr_un, sun_path))
+    return ""; // Unnamed domain socket
+
+  llvm::StringRef name(saddr_un.sun_path + GetNameOffset(),
+                       sock_addr_len - offsetof(struct sockaddr_un, sun_path) -
                            GetNameOffset());
-      if (name.back() == '\0') name.pop_back();
-      return name;
-    }
-  }
-  return "";
+  if (name.back() == '\0')
+    name = name.drop_back();
+
+  return name.str();
 }
 
 std::string DomainSocket::GetRemoteConnectionURI() const {
-  if (m_socket != kInvalidSocketValue) {
-    return std::string(llvm::formatv(
-        "{0}://{1}",
-        GetNameOffset() == 0 ? "unix-connect" : "unix-abstract-connect",
-        GetSocketName()));
-  }
-  return "";
+  std::string name = GetSocketName();
+  if (name.empty())
+    return name;
+
+  return llvm::formatv(
+      "{0}://{1}",
+      GetNameOffset() == 0 ? "unix-connect" : "unix-abstract-connect", name);
 }
diff --git a/lldb/unittests/Host/SocketTest.cpp b/lldb/unittests/Host/SocketTest.cpp
index 27d42f835718..5593b7726919 100644
--- a/lldb/unittests/Host/SocketTest.cpp
+++ b/lldb/unittests/Host/SocketTest.cpp
@@ -225,6 +225,8 @@ TEST_P(SocketTest, DomainGetConnectURI) {
   EXPECT_TRUE(UriParser::Parse(uri, scheme, hostname, port, path));
   EXPECT_EQ(scheme, "unix-connect");
   EXPECT_EQ(path, domain_path);
+
+  EXPECT_EQ(socket_b_up->GetRemoteConnectionURI(), "");
 }
 #endif