gresolio · December 3, 2021 13:34 · Dec 3, 2021
diff --git a/gethostnamew_nt60_by_kampeador.c b/gethostnamew_nt60_by_kampeador.c
@@ -0,0 +1,197 @@
+/* Fixed compatibility issue with windows 7 #3285 (kampeador) https://github.com/libuv/libuv/pull/3285 */
+
+#pragma comment(lib, "ws2_32.lib")
+
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+
+#include <winsock2.h>
+#include <windows.h>
+#include <svcguid.h>
+
+/* Local buffer size for WSAQUERYSETW data inside uv__gethostnamew_nt60
+   sizeof(WSAQUERYSETW) + 512 = 632 bytes to match GetHostNameW behavior */
+#define WSAQ_LOCAL_BUF_LEN (sizeof(WSAQUERYSETW) + 512)
+
+/* Parameters for WSAQUERYSETW inside uv__gethostnamew_nt60 */
+static GUID guid_host_name = SVCID_HOSTNAME;
+static AFPROTOCOLS af_protocols[2] = { {AF_INET, IPPROTO_UDP},
+                                       {AF_INET, IPPROTO_TCP} };
+
+typedef void* (*uv_malloc_func)(size_t size);
+typedef void* (*uv_realloc_func)(void* ptr, size_t size);
+typedef void* (*uv_calloc_func)(size_t count, size_t size);
+typedef void (*uv_free_func)(void* ptr);
+
+typedef struct {
+    uv_malloc_func local_malloc;
+    uv_realloc_func local_realloc;
+    uv_calloc_func local_calloc;
+    uv_free_func local_free;
+} uv__allocator_t;
+
+static uv__allocator_t uv__allocator = {
+    malloc,
+    realloc,
+    calloc,
+    free,
+};
+
+
+void* uv__malloc(size_t size) {
+    if (size > 0)
+        return uv__allocator.local_malloc(size);
+    return NULL;
+}
+
+
+void uv__free(void* ptr) {
+    int saved_errno;
+
+    /* Libuv expects that free() does not clobber errno.  The system allocator
+     * honors that assumption but custom allocators may not be so careful.
+     */
+    saved_errno = errno;
+    uv__allocator.local_free(ptr);
+    errno = saved_errno;
+}
+
+
+static int WSAAPI uv__gethostnamew_nt60(PWSTR name, int name_len) {
+    int result_len;
+    int error_code = NO_ERROR;
+
+    /* WSALookupService stuff
+     * Avoid dynamic memory allocation if possible */
+    CHAR local_buf[WSAQ_LOCAL_BUF_LEN];
+    DWORD dwlen = WSAQ_LOCAL_BUF_LEN;
+    WSAQUERYSETW* pwsaq;
+    /* hostname returned from WSALookupService stage */
+    WCHAR* result_name = NULL;
+    /* WSALookupService handle */
+    HANDLE hlookup;
+    /* Fallback to heap allocation if stack buffer is too small */
+    WSAQUERYSETW* heap_data = NULL;
+
+    /* check input */
+    if (name == NULL) {
+        error_code = WSAEFAULT;
+        goto cleanup;
+    }
+
+    /*
+     * Stage 1: Check environment variable
+     * _CLUSTER_NETWORK_NAME_ len == ComputeName(NETBIOS) len.
+     * i.e 15 characters + null.
+     * It overrides the actual hostname, so application can
+     * work when network name and computer name are different
+     */
+    result_len = GetEnvironmentVariableW(L"_CLUSTER_NETWORK_NAME_",
+        name,
+        name_len);
+    if (result_len != 0) {
+        if (result_len > name_len) {
+            error_code = WSAEFAULT;
+        }
+        goto cleanup;
+    }
+
+    /* Stage 2: Do normal lookup through WSALookupServiceLookup */
+    pwsaq = (WSAQUERYSETW*)local_buf;
+    memset(pwsaq, 0, sizeof(*pwsaq));
+    pwsaq->dwSize = sizeof(*pwsaq);
+    pwsaq->lpszServiceInstanceName = NULL;
+    pwsaq->lpServiceClassId = &guid_host_name;
+    pwsaq->dwNameSpace = NS_ALL;
+    pwsaq->lpafpProtocols = &af_protocols[0];
+    pwsaq->dwNumberOfProtocols = 2;
+
+    error_code = WSALookupServiceBeginW(pwsaq, LUP_RETURN_NAME, &hlookup);
+    if (error_code == NO_ERROR) {
+        /* Try stack allocation first */
+        error_code = WSALookupServiceNextW(hlookup, 0, &dwlen, pwsaq);
+        if (error_code == NO_ERROR) {
+            result_name = pwsaq->lpszServiceInstanceName;
+        }
+        else {
+            error_code = WSAGetLastError();
+
+            if (error_code == WSAEFAULT) {
+                /* Should never happen */
+                assert(sizeof(CHAR) * dwlen >= sizeof(WSAQUERYSETW));
+
+                /* Fallback to the heap allocation */
+                heap_data = uv__malloc(sizeof(CHAR) * (size_t)dwlen);
+                if (heap_data != NULL) {
+                    error_code = WSALookupServiceNextW(hlookup, 0, &dwlen, heap_data);
+                    if (error_code == NO_ERROR) {
+                        result_name = heap_data->lpszServiceInstanceName;
+                    }
+                    else {
+                        error_code = WSAGetLastError();
+                    }
+                }
+                else {
+                    error_code = WSA_NOT_ENOUGH_MEMORY;
+                }
+            }
+        }
+
+        WSALookupServiceEnd(hlookup);
+
+        if (error_code != NO_ERROR) {
+            WSASetLastError(error_code);
+        }
+    }
+
+    if (result_name != NULL) {
+        size_t wlen = wcslen(result_name) + 1;
+
+        if (wlen <= (size_t)name_len) {
+            wmemcpy(name, result_name, wlen);
+        }
+        else {
+            error_code = WSAEFAULT;
+        }
+        goto cleanup;
+    }
+
+    /* Stage 3: If WSALookupServiceLookup fails, fallback to GetComputerName */
+    result_len = name_len;
+    /* Reset error code */
+    error_code = NO_ERROR;
+
+    if (GetComputerNameW(name, (PDWORD)&result_len) == FALSE) {
+        error_code = WSAENETDOWN;
+        if (result_len >= name_len) {
+            error_code = WSAEFAULT;
+        }
+    }
+
+cleanup:
+    uv__free(heap_data);
+
+    if (error_code == NO_ERROR) {
+        return NO_ERROR;
+    }
+    else {
+        WSASetLastError(error_code);
+        return SOCKET_ERROR;
+    }
+}
+
+
+int main()
+{
+    WCHAR buf[256];
+    int result;
+
+    result = uv__gethostnamew_nt60(buf, sizeof(buf));
+    wprintf(L"result: %d, hostname: '%ls'\n", result, buf);
+
+    return 0;
+}