Inherit handles only if necessary on Windows

Refs #2779 <https://github.com/Genymobile/scrcpy/issues/2779>

app/src/sys/win/process.c

@@ -26,6 +26,8 @@ sc_process_execute_p(const char *const argv[], HANDLE *handle,
                      HANDLE *pin, HANDLE *pout, HANDLE *perr) {
     enum sc_process_result ret = SC_PROCESS_ERROR_GENERIC;
 
+    bool inherit_handles = pin || pout || perr;
+
     SECURITY_ATTRIBUTES sa;
     sa.nLength = sizeof(SECURITY_ATTRIBUTES);
     sa.lpSecurityDescriptor = NULL;
@@ -69,7 +71,7 @@ sc_process_execute_p(const char *const argv[], HANDLE *handle,
     PROCESS_INFORMATION pi;
     memset(&si, 0, sizeof(si));
     si.cb = sizeof(si);
-    if (pin || pout || perr) {
+    if (inherit_handles) {
         si.dwFlags = STARTF_USESTDHANDLES;
         if (pin) {
             si.hStdInput = stdin_read_handle;
@@ -95,8 +97,8 @@ sc_process_execute_p(const char *const argv[], HANDLE *handle,
         goto error_close_stderr;
     }
 
-    if (!CreateProcessW(NULL, wide, NULL, NULL, TRUE, 0, NULL, NULL, &si,
-                        &pi)) {
+    if (!CreateProcessW(NULL, wide, NULL, NULL, inherit_handles, 0, NULL, NULL,
+                        &si, &pi)) {
         free(wide);
         *handle = NULL;
 

app/src/util/net.c

@@ -96,6 +96,27 @@ net_perror(const char *s) {
 sc_socket
 net_socket(void) {
     sc_raw_socket raw_sock = socket(AF_INET, SOCK_STREAM, 0);
+
+#ifdef _WIN32
+    /* To be able to communicate with a child process via stdin, stdout and
+     * stderr, the CreateProcess() parameter bInheritHandles must be set to
+     * TRUE. But this causes *all* handles to be inherited, including sockets.
+     *
+     * One possibility could be to use an extended API to set extra attributes
+     * on process creation:
+     *  - <https://stackoverflow.com/a/28185363/1987178>
+     *  - <https://devblogs.microsoft.com/oldnewthing/20111216-00/?p=8873>
+     * But it seems that this API is not available on MinGW (it does not
+     * compile).
+     *
+     * As an alternative, explicitly mark all sockets as non-inheritable.
+     */
+    if (!SetHandleInformation((HANDLE) raw_sock, HANDLE_FLAG_INHERIT, 0)) {
+        closesocket(raw_sock);
+        return SC_SOCKET_NONE;
+    }
+#endif
+
     sc_socket sock = wrap(raw_sock);
     if (sock == SC_SOCKET_NONE) {
         net_perror("socket");