[Lldb-commits] [lldb] [lldb] Fix lldb-server host and port address parsing (PR #191414)

[Georgiy Samoylov via lldb-commits]

https://github.com/sga-sc created https://github.com/llvm/llvm-project/pull/191414

This patch fixes 2 problems in lldb-server argument parser:

1. Let's try to start lldb-server with incorrect arguments

```
./lldb-server platform --listen *:1111--server
```
Current behavior
 * lldb-server run in gdbserver mode with port 1111

Expected behavior
 * fail, as `1111–server` is not a number

2. And try to start lldb-server with host:port specification without colon
```
./lldb-server gdbserver 1111 ./test 
Launched './test' as process 186...
lldb-server-local_build
lldb-server: llvm-project/lldb/source/Host/common/TCPSocket.cpp:245: virtual Status lldb_private::TCPSocket::Listen(llvm::StringRef, int): Assertion `error.Fail()' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: ./lldb-server gdbserver 1111 ./test
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  lldb-server     0x0000002ab86d0ca2
1  lldb-server     0x0000002ab86ced06
2  lldb-server     0x0000002ab86d1428
3  linux-vdso.so.1 0x0000003f8e7fd800 __vdso_rt_sigreturn + 0
4  libc.so.6       0x0000003f8e2b264a
5  libc.so.6       0x0000003f8e27b1ac gsignal + 18
6  libc.so.6       0x0000003f8e26c14c abort + 180
7  libc.so.6       0x0000003f8e2760cc
8  libc.so.6       0x0000003f8e27610e __assert_perror_fail + 0
9  lldb-server     0x0000002ab86eb628
10 lldb-server     0x0000002ab86f1010
11 lldb-server     0x0000002ab86eeee0
12 lldb-server     0x0000002ab86eee5c
13 lldb-server     0x0000002ab863ef3a
14 lldb-server     0x0000002ab864067c
15 lldb-server     0x0000002ab86438da
16 libc.so.6       0x0000003f8e26c476
17 libc.so.6       0x0000003f8e26c51e __libc_start_main + 116
18 lldb-server     0x0000002ab863ce64
Aborted
```

>From d71a9d363c966765014c350c674ff530b0284a74 Mon Sep 17 00:00:00 2001
From: Georgiy Samoylov <Ignitor21838 at gmail.com>
Date: Fri, 10 Apr 2026 16:06:13 +0300
Subject: [PATCH] [lldb] Fix host and port address parsing

---
 lldb/source/Host/common/Socket.cpp | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/lldb/source/Host/common/Socket.cpp b/lldb/source/Host/common/Socket.cpp
index 041dfbda0c21d..134591ebf9929 100644
--- a/lldb/source/Host/common/Socket.cpp
+++ b/lldb/source/Host/common/Socket.cpp
@@ -290,7 +290,12 @@ Socket::UdpConnect(llvm::StringRef host_and_port) {
 
 llvm::Expected<Socket::HostAndPort>
 Socket::DecodeHostAndPort(llvm::StringRef host_and_port) {
-  static llvm::Regex g_regex("([^:]+|\\[[0-9a-fA-F:]+.*\\]):([0-9]+)");
+  // This regex parses host:port combinations, supporting:
+  // - IPv4 sockets (e.g., "127.0.0.1:8080")
+  // - IPv6 sockets with host part in square brackets (e.g., "[::1]:80")
+  // Group 1: Address (IPv4, hostname, or IPv6 in [])
+  // Group 2: Port number (digits only)
+  static llvm::Regex g_regex("([^:]+|\\[[0-9a-fA-F:]+.*\\]):([0-9]+$)");
   HostAndPort ret;
   llvm::SmallVector<llvm::StringRef, 3> matches;
   if (g_regex.match(host_and_port, &matches)) {
@@ -300,16 +305,13 @@ Socket::DecodeHostAndPort(llvm::StringRef host_and_port) {
       ret.hostname = ret.hostname.substr(1, ret.hostname.size() - 2);
     if (to_integer(matches[2], ret.port, 10))
       return ret;
-  } else {
-    // If this was unsuccessful, then check if it's simply an unsigned 16-bit
-    // integer, representing a port with an empty host.
-    if (to_integer(host_and_port, ret.port, 10))
-      return ret;
   }
 
-  return llvm::createStringError(llvm::inconvertibleErrorCode(),
-                                 "invalid host:port specification: '%s'",
-                                 host_and_port.str().c_str());
+  return llvm::createStringError(
+      llvm::inconvertibleErrorCode(),
+      "invalid host:port specification: '%s', both IPv4 (e.g., localhost:8080) "
+      "or IPv6 (e.g, [2001:db8::1]:8080) formats are supported",
+      host_and_port.str().c_str());
 }
 
 IOObject::WaitableHandle Socket::GetWaitableHandle() {