Support SO_LINGER socket option.

When SO_LINGER option is enabled, the close will not return until all the
queued messages are sent and acknowledged for the socket or linger timeout is
reached. If the option is not set, close will return immediately. This option
is mainly supported for connection oriented protocols such as TCP.

PiperOrigin-RevId: 328350576

2 files changed, 149 insertions, 0 deletions

diff --git a/test/syscalls/linux/socket_ip_tcp_generic.cc b/test/syscalls/linux/socket_ip_tcp_generic.cc
index 04356b780..f4b69c46c 100644
--- a/test/syscalls/linux/socket_ip_tcp_generic.cc
+++ b/test/syscalls/linux/socket_ip_tcp_generic.cc
@@ -1080,5 +1080,124 @@ TEST_P(TCPSocketPairTest, TCPResetDuringClose_NoRandomSave) {
   }
 }
 
+// Test setsockopt and getsockopt for a socket with SO_LINGER option.
+TEST_P(TCPSocketPairTest, SetAndGetLingerOption) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  // Check getsockopt before SO_LINGER option is set.
+  struct linger got_linger = {-1, -1};
+  socklen_t got_len = sizeof(got_linger);
+
+  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
+                         &got_linger, &got_len),
+              SyscallSucceeds());
+  ASSERT_THAT(got_len, sizeof(got_linger));
+  struct linger want_linger = {};
+  EXPECT_EQ(0, memcmp(&want_linger, &got_linger, got_len));
+
+  // Set and get SO_LINGER with negative values.
+  struct linger sl;
+  sl.l_onoff = 1;
+  sl.l_linger = -3;
+  ASSERT_THAT(
+      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
+      SyscallSucceeds());
+  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
+                         &got_linger, &got_len),
+              SyscallSucceeds());
+  ASSERT_EQ(got_len, sizeof(got_linger));
+  EXPECT_EQ(sl.l_onoff, got_linger.l_onoff);
+  // Linux returns a different value as it uses HZ to convert the seconds to
+  // jiffies which overflows for negative values. We want to be compatible with
+  // linux for getsockopt return value.
+  if (IsRunningOnGvisor()) {
+    EXPECT_EQ(sl.l_linger, got_linger.l_linger);
+  }
+
+  // Set and get SO_LINGER option with positive values.
+  sl.l_onoff = 1;
+  sl.l_linger = 5;
+  ASSERT_THAT(
+      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
+      SyscallSucceeds());
+  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
+                         &got_linger, &got_len),
+              SyscallSucceeds());
+  ASSERT_EQ(got_len, sizeof(got_linger));
+  EXPECT_EQ(0, memcmp(&sl, &got_linger, got_len));
+}
+
+// Test socket to disable SO_LINGER option.
+TEST_P(TCPSocketPairTest, SetOffLingerOption) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  // Set the SO_LINGER option.
+  struct linger sl;
+  sl.l_onoff = 1;
+  sl.l_linger = 5;
+  ASSERT_THAT(
+      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
+      SyscallSucceeds());
+
+  // Check getsockopt after SO_LINGER option is set.
+  struct linger got_linger = {-1, -1};
+  socklen_t got_len = sizeof(got_linger);
+  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
+                         &got_linger, &got_len),
+              SyscallSucceeds());
+  ASSERT_EQ(got_len, sizeof(got_linger));
+  EXPECT_EQ(0, memcmp(&sl, &got_linger, got_len));
+
+  sl.l_onoff = 0;
+  sl.l_linger = 5;
+  ASSERT_THAT(
+      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
+      SyscallSucceeds());
+
+  // Check getsockopt after SO_LINGER option is set to zero.
+  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
+                         &got_linger, &got_len),
+              SyscallSucceeds());
+  ASSERT_EQ(got_len, sizeof(got_linger));
+  EXPECT_EQ(0, memcmp(&sl, &got_linger, got_len));
+}
+
+// Test close on dup'd socket with SO_LINGER option set.
+TEST_P(TCPSocketPairTest, CloseWithLingerOption) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  // Set the SO_LINGER option.
+  struct linger sl;
+  sl.l_onoff = 1;
+  sl.l_linger = 5;
+  ASSERT_THAT(
+      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
+      SyscallSucceeds());
+
+  // Check getsockopt after SO_LINGER option is set.
+  struct linger got_linger = {-1, -1};
+  socklen_t got_len = sizeof(got_linger);
+  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
+                         &got_linger, &got_len),
+              SyscallSucceeds());
+  ASSERT_EQ(got_len, sizeof(got_linger));
+  EXPECT_EQ(0, memcmp(&sl, &got_linger, got_len));
+
+  FileDescriptor dupFd = FileDescriptor(dup(sockets->first_fd()));
+  ASSERT_THAT(close(sockets->release_first_fd()), SyscallSucceeds());
+  char buf[10] = {};
+  // Write on dupFd should succeed as socket will not be closed until
+  // all references are removed.
+  ASSERT_THAT(RetryEINTR(write)(dupFd.get(), buf, sizeof(buf)),
+              SyscallSucceedsWithValue(sizeof(buf)));
+  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
+              SyscallFailsWithErrno(EBADF));
+
+  // Close the socket.
+  dupFd.reset();
+  // Write on dupFd should fail as all references for socket are removed.
+  ASSERT_THAT(RetryEINTR(write)(dupFd.get(), buf, sizeof(buf)),
+              SyscallFailsWithErrno(EBADF));
+}
 }  // namespace testing
 }  // namespace gvisor
diff --git a/test/syscalls/linux/socket_ip_udp_generic.cc b/test/syscalls/linux/socket_ip_udp_generic.cc
index edb86aded..5cad6f017 100644
--- a/test/syscalls/linux/socket_ip_udp_generic.cc
+++ b/test/syscalls/linux/socket_ip_udp_generic.cc
@@ -448,5 +448,35 @@ TEST_P(UDPSocketPairTest, TClassRecvMismatch) {
               SyscallFailsWithErrno(EOPNOTSUPP));
 }
 
+// Test the SO_LINGER option can be set/get on udp socket.
+TEST_P(UDPSocketPairTest, SoLingerFail) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+  int level = SOL_SOCKET;
+  int type = SO_LINGER;
+
+  struct linger sl;
+  sl.l_onoff = 1;
+  sl.l_linger = 5;
+  ASSERT_THAT(setsockopt(sockets->first_fd(), level, type, &sl, sizeof(sl)),
+              SyscallSucceedsWithValue(0));
+
+  struct linger got_linger = {};
+  socklen_t length = sizeof(sl);
+  ASSERT_THAT(
+      getsockopt(sockets->first_fd(), level, type, &got_linger, &length),
+      SyscallSucceedsWithValue(0));
+
+  ASSERT_EQ(length, sizeof(got_linger));
+  // Linux returns the values which are set in the SetSockOpt for SO_LINGER.
+  // In gVisor, we do not store the linger values for UDP as SO_LINGER for UDP
+  // is a no-op.
+  if (IsRunningOnGvisor()) {
+    struct linger want_linger = {};
+    EXPECT_EQ(0, memcmp(&want_linger, &got_linger, length));
+  } else {
+    EXPECT_EQ(0, memcmp(&sl, &got_linger, length));
+  }
+}
+
 }  // namespace testing
 }  // namespace gvisor