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Diffstat (limited to 'include/ruby/internal/intern/select/largesize.h')
| -rw-r--r-- | include/ruby/internal/intern/select/largesize.h | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/include/ruby/internal/intern/select/largesize.h b/include/ruby/internal/intern/select/largesize.h new file mode 100644 index 0000000000..d65f088c06 --- /dev/null +++ b/include/ruby/internal/intern/select/largesize.h @@ -0,0 +1,214 @@ +#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 */ |