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#ifndef RBIMPL_INTERN_SELECT_LARGESIZE_H /*-*-C++-*-vi:se ft=cpp:*/
#define RBIMPL_INTERN_SELECT_LARGESIZE_H
/**
* @file
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are
* implementation details. Don't take them as canon. They could
* rapidly appear then vanish. The name (path) of this header file
* is also an implementation detail. Do not expect it to persist
* at the place it is now. Developers are free to move it anywhere
* anytime at will.
* @note To ruby-core: remember that this header can be possibly
* recursively included from extension libraries written in C++.
* Do not expect for instance `__VA_ARGS__` is always available.
* We assume C99 for ruby itself but we don't assume languages of
* extension libraries. They could be written in C++98.
* @brief Public APIs to provide ::rb_fd_select().
*
* Several Unix platforms support file descriptors bigger than FD_SETSIZE in
* `select(2)` system call.
*
* - Linux 2.2.12 (?)
*
* - NetBSD 1.2 (src/sys/kern/sys_generic.c:1.25)
* `select(2)` documents how to allocate fd_set dynamically.
* http://netbsd.gw.com/cgi-bin/man-cgi?select++NetBSD-4.0
*
* - FreeBSD 2.2 (src/sys/kern/sys_generic.c:1.19)
*
* - OpenBSD 2.0 (src/sys/kern/sys_generic.c:1.4)
* `select(2)` documents how to allocate fd_set dynamically.
* http://www.openbsd.org/cgi-bin/man.cgi?query=select&manpath=OpenBSD+4.4
*
* - Solaris 8 has `select_large_fdset`
*
* - Mac OS X 10.7 (Lion)
* `select(2)` returns `EINVAL` if `nfds` is greater than `FD_SET_SIZE` and
* `_DARWIN_UNLIMITED_SELECT` (or `_DARWIN_C_SOURCE`) isn't defined.
* http://developer.apple.com/library/mac/#releasenotes/Darwin/SymbolVariantsRelNotes/_index.html
*
* When `fd_set` is not big enough to hold big file descriptors, it should be
* allocated dynamically. Note that this assumes `fd_set` is structured as
* bitmap.
*
* `rb_fd_init` allocates the memory.
* `rb_fd_term` frees the memory.
* `rb_fd_set` may re-allocate bitmap.
*
* So `rb_fd_set` doesn't reject file descriptors bigger than `FD_SETSIZE`.
*/
#include "ruby/internal/attr/nonnull.h"
#include "ruby/internal/attr/pure.h"
#include "ruby/internal/dllexport.h"
/**@cond INTERNAL_MACRO */
#define rb_fd_ptr rb_fd_ptr
#define rb_fd_max rb_fd_max
/** @endcond */
struct timeval;
/**
* The data structure which wraps the fd_set bitmap used by select(2). This
* allows Ruby to use FD sets larger than that allowed by historic limitations
* on modern platforms.
*/
typedef struct {
int maxfd; /**< Maximum allowed number of FDs. */
fd_set *fdset; /**< File descriptors buffer */
} rb_fdset_t;
RBIMPL_SYMBOL_EXPORT_BEGIN()
RBIMPL_ATTR_NONNULL(())
/**
* (Re-)initialises a fdset. One must be initialised before other `rb_fd_*`
* operations. Analogous to calling `malloc(3)` to allocate an `fd_set`.
*
* @param[out] f An fdset to squash.
* @post `f` holds no file descriptors.
*/
void rb_fd_init(rb_fdset_t *f);
RBIMPL_ATTR_NONNULL(())
/**
* Destroys the ::rb_fdset_t, releasing any memory and resources it used. It
* must be reinitialised using rb_fd_init() before future use. Analogous to
* calling `free(3)` to release memory for an `fd_set`.
*
* @param[out] f An fdset to squash.
* @post `f` holds no file descriptors.
*/
void rb_fd_term(rb_fdset_t *f);
RBIMPL_ATTR_NONNULL(())
/**
* Wipes out the current set of FDs.
*
* @param[out] f The fdset to clear.
* @post `f` has no FDs.
*/
void rb_fd_zero(rb_fdset_t *f);
RBIMPL_ATTR_NONNULL(())
/**
* Sets an fd to a fdset.
*
* @param[in] fd A file descriptor.
* @param[out] f Target fdset.
* @post `f` holds `fd`.
*/
void rb_fd_set(int fd, rb_fdset_t *f);
RBIMPL_ATTR_NONNULL(())
/**
* Releases a specific FD from the given fdset.
*
* @param[in] fd Target FD.
* @param[out] f The fdset that holds `fd`.
* @post `f` doesn't hold n.
*/
void rb_fd_clr(int fd, rb_fdset_t *f);
RBIMPL_ATTR_NONNULL(())
RBIMPL_ATTR_PURE()
/**
* Queries if the given FD is in the given set.
*
* @param[in] fd Target FD.
* @param[in] f The fdset to scan.
* @retval 1 Yes there is.
* @retval 0 No there isn't.
* @see http://www.freebsd.org/cgi/query-pr.cgi?pr=91421
*/
int rb_fd_isset(int fd, const rb_fdset_t *f);
/**
* Destructively overwrites an fdset with another.
*
* @param[out] dst Target fdset.
* @param[in] src Source fdset.
* @param[in] max Maximum number of file descriptors to copy.
* @post `dst` is a copy of `src`.
*/
void rb_fd_copy(rb_fdset_t *dst, const fd_set *src, int max);
/**
* Identical to rb_fd_copy(), except it copies unlimited number of file
* descriptors.
*
* @param[out] dst Target fdset.
* @param[in] src Source fdset.
* @post `dst` is a copy of `src`.
*/
void rb_fd_dup(rb_fdset_t *dst, const rb_fdset_t *src);
/**
* Waits for multiple file descriptors at once.
*
* @param[in] nfds Max FD in everything passed, plus one.
* @param[in,out] rfds Set of FDs to wait for reads.
* @param[in,out] wfds Set of FDs to wait for writes.
* @param[in,out] efds Set of FDs to wait for OOBs.
* @param[in,out] timeout Max blocking duration.
* @retval -1 Failed, errno set.
* @retval 0 Timeout exceeded.
* @retval otherwise Total number of file descriptors returned.
* @post `rfds` contains readable FDs.
* @post `wfds` contains writable FDs.
* @post `efds` contains exceptional FDs.
* @post `timeout` is the time left.
* @note All pointers are allowed to be null pointers.
*/
int rb_fd_select(int nfds, rb_fdset_t *rfds, rb_fdset_t *wfds, rb_fdset_t *efds, struct timeval *timeout);
RBIMPL_SYMBOL_EXPORT_END()
RBIMPL_ATTR_NONNULL(())
RBIMPL_ATTR_PURE()
/**
* Raw pointer to `fd_set`.
*
* @param[in] f Target fdset.
* @retval NULL `f` is already terminated by rb_fd_term().
* @retval otherwise Underlying fd_set.
*
* @internal
*
* Extension library must not touch raw pointers. It was a bad idea to let
* them use it.
*/
static inline fd_set *
rb_fd_ptr(const rb_fdset_t *f)
{
return f->fdset;
}
RBIMPL_ATTR_NONNULL(())
RBIMPL_ATTR_PURE()
/**
* It seems this function has no use. Maybe just remove?
*
* @param[in] f A set.
* @return Number of file descriptors stored.
*/
static inline int
rb_fd_max(const rb_fdset_t *f)
{
return f->maxfd;
}
#endif /* RBIMPL_INTERN_SELECT_LARGESIZE_H */
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