[all-commits] [llvm/llvm-project] 926a7e: [lldb] Fix TCPSocket::Connect when getaddrinfo ret...
Pavel Labath via All-commits
all-commits at lists.llvm.org
Mon Jun 13 23:49:24 PDT 2022
Author: Pavel Labath <pavel at labath.sk>
Date: 2022-06-14 (Tue, 14 Jun 2022)
[lldb] Fix TCPSocket::Connect when getaddrinfo returns multiple addrs
TCPSocket::Connect() calls SocketAddress::GetAddressInfo() and tries to
connect any of them (in a for loop).
This used to work before commit 4f6d3a376c9f("[LLDB] Fix setting of
success in Socket::Close()") https://reviews.llvm.org/D116768.
As a side effect of that commit, TCPSocket can only connect to the first
address returned by SocketAddress::GetAddressInfo().
1. If the attempt to connect to the first address fails,
TCPSocket::Connect(), calls CLOSE_SOCKET(GetNativeSocket()), which
closes the fd, but DOES NOT set m_socket to kInvalidSocketValue.
2. On the second attempt, TCPSocket::CreateSocket() calls
3. Socket::Close() proceeds, because IsValid() is true (m_socket was not
reset on step 1).
4. Socket::Close() calls ::close(m_socket), which fails
5. Since commit 4f6d3a376c9f("[LLDB] Fix setting of success in
Socket::Close()"), this is error is detected. Socket::Close() returns
6. TCPSocket::CreateSocket() therefore returns an error.
7. TCPSocket::Connect() detects the error and continues, skipping the
second (and the third, fourth...) address.
This commit fixes the problem by changing step 1: by calling
Socket::Close, instead of directly calling close(m_socket), m_socket is
also se to kInvalidSocketValue. On step 3, Socket::Close() is going to
return immediately and, on step 6, TCPSocket::CreateSocket() does not
How to reproduce this problem:
On my system, getaddrinfo() resolves "localhost" to "::1" (first) and to
Start a gdbserver that only listens on 127.0.0.1:
gdbserver 127.0.0.1:2159 /bin/cat
Process /bin/cat created; pid = 2146709
Listening on port 2159
Start lldb and make it connect to "localhost:2159"
(lldb) gdb-remote localhost:2159
Before 4f6d3a376c9f("[LLDB] Fix setting of success in Socket::Close()"),
this used to work. After that commit, it stopped working. This commit
fixes the problem.
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D126702
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