From 51e45db81ccf520e808ef35cfdd1b7b85018848c Mon Sep 17 00:00:00 2001
From: Larry Frieson <larryf@mlinks.net>
Date: Thu, 14 Dec 2023 22:40:43 -0800
Subject: [PATCH] Return actual socket errors on Windows.

---
 lib/net.cpp   | 29 +++++++++++++++++++++++------
 src/socketx.h |  2 ++
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/lib/net.cpp b/lib/net.cpp
index beacfcb7b8..685ee9e11a 100644
--- a/lib/net.cpp
+++ b/lib/net.cpp
@@ -15,6 +15,25 @@
 
 // https://wiki.openssl.org/index.php/SSL/TLS_Client
 
+static std::string socket_error_message(int err)
+{
+#ifdef _WIN32
+    char msgbuf[256];
+    DWORD r = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+                            NULL,
+                            err,
+                            MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                            msgbuf,
+                            sizeof(msgbuf),
+                            NULL);
+    if (r == 0) {
+        snprintf(msgbuf, sizeof(msgbuf), "(No Error Text) - %d", err);
+    }
+    return msgbuf;
+#endif
+    return strerror(err);
+}
+
 class SocketObject: public Object {
 public:
     SocketObject() {}
@@ -133,9 +152,8 @@ class RawSocketObject: public SocketObject {
         std::vector<unsigned char> buffer(n);
         int r = ::recv(handle, reinterpret_cast<char *>(const_cast<unsigned char *>(buffer.data())), n, 0);
         if (r < 0) {
-            int err = errno;
-            perror("recv");
-            return Cell(std::vector<Cell> {Cell(number_from_uint32(CHOICE_RecvResult_error)), Cell(utf8string(strerror(err)))});
+            int err = socket_error();
+            return Cell(std::vector<Cell> {Cell(number_from_uint32(CHOICE_RecvResult_error)), Cell(utf8string(socket_error_message(err)))});
         }
         if (r == 0) {
             return Cell(std::vector<Cell> {Cell(number_from_uint32(CHOICE_RecvResult_eof))});
@@ -150,9 +168,8 @@ class RawSocketObject: public SocketObject {
         socklen_t sin_len = sizeof(sin);
         int r = ::recvfrom(handle, reinterpret_cast<char *>(const_cast<unsigned char *>(buffer.data())), n, 0, reinterpret_cast<sockaddr *>(&sin), &sin_len);
         if (r < 0) {
-            int err = errno;
-            perror("recvfrom");
-            return Cell(std::vector<Cell> {Cell(number_from_uint32(CHOICE_RecvFromResult_error)), Cell(utf8string(strerror(err)))});
+            int err = socket_error();
+            return Cell(std::vector<Cell> {Cell(number_from_uint32(CHOICE_RecvFromResult_error)), Cell(utf8string(socket_error_message(err)))});
         }
         if (r == 0) {
             return Cell(std::vector<Cell> {Cell(number_from_uint32(CHOICE_RecvFromResult_eof))});
diff --git a/src/socketx.h b/src/socketx.h
index eece91497b..aeade61a4b 100644
--- a/src/socketx.h
+++ b/src/socketx.h
@@ -3,6 +3,7 @@
 #include <winsock.h>
 typedef int socklen_t;
 #pragma warning(disable: 4127) // incompatible with FD_SET()
+#define socket_error()  WSAGetLastError()
 
 #else
 
@@ -15,5 +16,6 @@ typedef int socklen_t;
 typedef int SOCKET;
 const int INVALID_SOCKET = -1;
 inline void closesocket(int x) { close(x); }
+#define socket_error()   errno
 
 #endif