fix(libc): fail freopen of an empty name with ENOENT on Windows

core/libs/prx/libc/CMakeLists.txt

@@ -652,6 +652,16 @@ if(BUILD_TESTING)
         set_tests_properties(file_streams PROPERTIES ENVIRONMENT_MODIFICATION
             "PATH=path_list_prepend:$<TARGET_FILE_DIR:libc>")
     endif()
+    add_test_executable(guest_freopen_host_standard_tests ${LIBS_INCLUDE_DIR}/tests/GuestFreopenHostStandard.cpp)
+    target_include_directories(guest_freopen_host_standard_tests PRIVATE ${LIBS_INCLUDE_DIR})
+    target_link_libraries(guest_freopen_host_standard_tests PRIVATE libc)
+    configure_windows_unwind(guest_freopen_host_standard_tests)
+    add_test(NAME guest_freopen_host_standard COMMAND guest_freopen_host_standard_tests)
+    set_tests_properties(guest_freopen_host_standard PROPERTIES TIMEOUT 20)
+    if(WIN32)
+        set_tests_properties(guest_freopen_host_standard PROPERTIES ENVIRONMENT_MODIFICATION
+            "PATH=path_list_prepend:$<TARGET_FILE_DIR:libc>")
+    endif()
     add_test_executable(guest_error_tests ${LIBS_INCLUDE_DIR}/tests/GuestErrors.cpp)
     target_include_directories(guest_error_tests PRIVATE ${LIBS_INCLUDE_DIR})
     target_link_libraries(guest_error_tests PRIVATE libc)

core/libs/prx/libc/src/FileAndHeap.cpp

@@ -361,14 +361,12 @@ FileStream* APS5_VABI freopen_nid_postfix(const char* filename, const char* mode
     if (!parsed) { errno = 22; return nullptr; }
     try {
         std::filesystem::path path;
-        if (*filename) {
-            if (const int error = ResolvePathError_nid_no_patch(filename, path)) {
-                if (stream->IsHostStandard()) stream->Detach();
-                else stream->Close();
-                if (stream->IsDynamic()) delete stream;
-                errno = error;
-                return nullptr;
-            }
+        if (const int error = *filename ? ResolvePathError_nid_no_patch(filename, path) : 2) {
+            if (stream->IsHostStandard()) stream->Detach();
+            else stream->Close();
+            if (stream->IsDynamic()) delete stream;
+            errno = error;
+            return nullptr;
         }
         if (stream->Reopen(path, parsed->native.c_str(), OpenNative)) {
 #ifdef _WIN32

core/libs/tests/GuestFreopenHostStandard.cpp

@@ -0,0 +1,77 @@
+#include "prx/libc/include/FileStream.hpp"
+#include "prx/libc/include/general/VabiMacros.hpp"
+#include <cerrno>
+#include <chrono>
+#include <cstdio>
+#include <cstdlib>
+#include <filesystem>
+#include <fstream>
+#include <iterator>
+#include <string>
+#include <fcntl.h>
+#ifdef _WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <io.h>
+#else
+#include <unistd.h>
+#endif
+
+extern "C" {
+FileStream* APS5_VABI freopen_nid_postfix(const char* filename, const char* mode, FileStream* stream);
+int APS5_VABI fputs_nid_postfix(const char* str, FileStream* stream);
+extern FileStream* __stdoutp_nid_postfix;
+}
+
+static void Require(bool value, int line) {
+    if (!value) {
+        std::fprintf(stderr, "freopen host standard check failed at line %d, errno %d\n", line, errno);
+        std::abort();
+    }
+}
+#define Check(value) Require((value), __LINE__)
+
+#ifdef _WIN32
+static int HostDup(int descriptor) { return ::_dup(descriptor); }
+static int HostDup2(int from, int to) { return ::_dup2(from, to); }
+static int HostClose(int descriptor) { return ::_close(descriptor); }
+static int HostWrite(int descriptor, const char* text, unsigned size) { return ::_write(descriptor, text, size); }
+static int HostFileno(std::FILE* stream) { return ::_fileno(stream); }
+#else
+static int HostDup(int descriptor) { return ::dup(descriptor); }
+static int HostDup2(int from, int to) { return ::dup2(from, to) == to ? 0 : -1; }
+static int HostClose(int descriptor) { return ::close(descriptor); }
+static int HostWrite(int descriptor, const char* text, unsigned size) { return static_cast<int>(::write(descriptor, text, size)); }
+static int HostFileno(std::FILE* stream) { return ::fileno(stream); }
+#endif
+
+static std::string Contents(const std::string& name) {
+    std::ifstream stream(name, std::ios::binary);
+    return std::string(std::istreambuf_iterator<char>(stream), std::istreambuf_iterator<char>());
+}
+
+int main() {
+    const auto sinkName = "anyps5-freopen-host-standard-" + std::to_string(std::chrono::steady_clock::now().time_since_epoch().count()) + ".txt";
+    std::FILE* sink = std::fopen(sinkName.c_str(), "wb");
+    Check(sink != nullptr);
+    const int original = HostDup(1);
+    Check(original >= 0 && HostDup2(HostFileno(sink), 1) == 0);
+
+    errno = 0;
+    FileStream* const reopened = freopen_nid_postfix("", "w", __stdoutp_nid_postfix);
+    const int error = errno;
+
+    const int written = HostWrite(1, "host", 4);
+    const bool restored = HostDup2(original, 1) == 0 && HostClose(original) == 0;
+    Check(std::fclose(sink) == 0);
+    Check(restored);
+    Check(reopened == nullptr);
+    Check(error == ENOENT);
+    Check(written == 4);
+    Check(Contents(sinkName) == "host");
+
+    errno = 0;
+    Check(fputs_nid_postfix("text", __stdoutp_nid_postfix) == -1 && errno == EBADF);
+    Check(std::filesystem::remove(sinkName));
+    return 0;
+}