openssl/ssl/rio/poll_builder.h

80 lines
2.5 KiB
C

/*
* 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