1 files changed, 79 insertions, 0 deletions
diff --git a/crypto/openssl/ssl/rio/poll_builder.h b/crypto/openssl/ssl/rio/poll_builder.h
new file mode 100644
index 000000000000..0a03f89df74d
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+++ b/crypto/openssl/ssl/rio/poll_builder.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright 2024-2025 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+#ifndef OSSL_POLL_BUILDER_H
+# define OSSL_POLL_BUILDER_H
+
+# include "poll_method.h"
+# include "internal/time.h"
+
+/*
+ * RIO_POLL_BUILDER
+ * ================
+ *
+ * RIO_POLL_BUILDER provides support for immediate-mode polling architectures.
+ * It abstracts OS-specific immediate-mode polling APIs such as select(2) and
+ * poll(2) and allows an arbitrarily large number of FDs to be polled for while
+ * providing minimal overhead (over the OS APIs themselves) for small numbers of
+ * FDs.
+ */
+typedef struct rio_poll_builder_st {
+# if RIO_POLL_METHOD == RIO_POLL_METHOD_NONE
+    int             unused_dummy; /* make microsoft compiler happy */
+# elif RIO_POLL_METHOD == RIO_POLL_METHOD_SELECT
+    fd_set          rfd, wfd, efd;
+    int             hwm_fd;
+# elif RIO_POLL_METHOD == RIO_POLL_METHOD_POLL
+#  define RIO_NUM_STACK_PFDS  32
+    struct pollfd   *pfd_heap;
+    struct pollfd   pfds[RIO_NUM_STACK_PFDS];
+    size_t          pfd_num, pfd_alloc;
+# else
+#  error Unknown RIO poll method
+# endif
+} RIO_POLL_BUILDER;
+
+/*
+ * Initialises a new poll builder.
+ *
+ * Returns 1 on success and 0 on failure.
+ */
+int ossl_rio_poll_builder_init(RIO_POLL_BUILDER *rpb);
+
+/*
+ * Tears down a poll builder, freeing any heap allocations (if any) which may
+ * have been made internally.
+ */
+void ossl_rio_poll_builder_cleanup(RIO_POLL_BUILDER *rpb);
+
+/*
+ * Adds a file descriptor to a poll builder. If want_read is 1, listens for
+ * readability events (POLLIN). If want_write is 1, listens for writability
+ * events (POLLOUT).
+ *
+ * If this is called with the same fd twice, the result equivalent to calling
+ * it one time with logically OR'd values of want_read and want_write.
+ *
+ * Returns 1 on success and 0 on failure.
+ */
+int ossl_rio_poll_builder_add_fd(RIO_POLL_BUILDER *rpb, int fd,
+                                 int want_read, int want_write);
+
+/*
+ * Polls the set of file descriptors added to a poll builder. deadline is a
+ * deadline time based on the ossl_time_now() clock or ossl_time_infinite() for
+ * no timeout. Returns 1 on success or 0 on failure.
+ */
+int ossl_rio_poll_builder_poll(RIO_POLL_BUILDER *rpb, OSSL_TIME deadline);
+
+/*
+ * TODO(RIO): No support currently for readout of what was readable/writeable as
+ * it is currently not needed.
+ */
+
+#endif