/*	$NetBSD: svc_fdset.c,v 1.4 2015/11/06 23:11:09 christos Exp $	*/

/*-
 * Copyright (c) 2015 The NetBSD Foundation, Inc.
 * All rights resefdsed.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Christos Zoulas.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__RCSID("$NetBSD: svc_fdset.c,v 1.4 2015/11/06 23:11:09 christos Exp $");


#include "reentrant.h"

#include <sys/fd_set.h>

#include <rpc/rpc.h>

#include <stdlib.h>
#include <string.h>

#undef svc_fdset
#undef svc_maxfd
extern fd_set svc_fdset;
extern int svc_maxfd;

struct svc_fdset {
	fd_set *fdset;
	int	fdmax;
	int	fdsize;
};

/* The single threaded, one global fd_set version */
static struct svc_fdset __svc_fdset;

static thread_key_t fdsetkey = -2;

#ifdef FDSET_DEBUG
#include <stdio.h>
#include <stdarg.h>
#include <unistd.h>
#include <lwp.h>

static void  __printflike(3, 0)
svc_header(const char *func, size_t line, const char *fmt, va_list ap)
{
	fprintf(stderr, "%s[%d.%d]: %s, %zu: ", getprogname(), (int)getpid(),
	    (int)_lwp_self(), func, line);
	vfprintf(stderr, fmt, ap);
	va_end(ap);
}

static void __printflike(4, 5)
svc_fdset_print(const char *func, size_t line, struct svc_fdset *fds, 
    const char *fmt, ...)
{
	va_list ap;
	const char *did = "";

	va_start(ap, fmt);
	svc_header(func, line, fmt, ap);
	va_end(ap);

	fprintf(stderr, "%p[%d] <", fds->fdset, fds->fdmax);
	for (int i = 0; i <= fds->fdmax; i++) {
		if (!FD_ISSET(i, fds->fdset))
			continue;
		fprintf(stderr, "%s%d", did, i);
		did = ", ";
	}
	fprintf(stderr, ">\n");
}

static void __printflike(3, 4)
svc_print(const char *func, size_t line, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	svc_header(func, line, fmt, ap);
	va_end(ap);
	fprintf(stderr, "\n");
}

#define DPRINTF(...)		svc_print(__func__, __LINE__, __VA_ARGS__)
#define DPRINTF_FDSET(...)	svc_fdset_print(__func__, __LINE__, __VA_ARGS__)

#else

#define DPRINTF(...)
#define DPRINTF_FDSET(...)

#endif


static inline void
svc_fdset_sanitize(struct svc_fdset *fds)
{
	while (fds->fdmax >= 0 && !FD_ISSET(fds->fdmax, fds->fdset))
		fds->fdmax--;
	/* Compat update */
	if (fds == &__svc_fdset) {
		svc_fdset = *__svc_fdset.fdset;
		svc_maxfd = __svc_fdset.fdmax;
	}
}

static void
svc_fdset_free(void *v)
{
	struct svc_fdset *fds = v;
	DPRINTF_FDSET(fds, "free");

	free(fds->fdset);
	free(fds);
}

static struct svc_fdset *
svc_fdset_resize(int fd, struct svc_fdset *fds)
{
	if (fds->fdset && fd < fds->fdsize) {
		DPRINTF_FDSET(fds, "keeping %d < %d", fd, fds->fdsize);
		return fds;
	}

	fd += FD_SETSIZE; 

	char *newfdset = realloc(fds->fdset, __NFD_BYTES(fd));
	if (newfdset == NULL)
		return NULL;

	memset(newfdset + __NFD_BYTES(fds->fdsize), 0,
	    __NFD_BYTES(fd) - __NFD_BYTES(fds->fdsize));


	fds->fdset = (void *)newfdset;
	DPRINTF_FDSET(fds, "resize %d > %d", fd, fds->fdsize);
	fds->fdsize = fd;

	return fds;
}

static struct svc_fdset *
svc_fdset_alloc(int fd)
{
	struct svc_fdset *fds;

	if (fdsetkey == -1)
		thr_keycreate(&fdsetkey, svc_fdset_free);

	if ((fds = thr_getspecific(fdsetkey)) == NULL) {

		fds = calloc(1, sizeof(*fds));
		if (fds == NULL)
			return NULL;

		(void)thr_setspecific(fdsetkey, fds);

		if (__svc_fdset.fdsize != 0) {
			*fds = __svc_fdset;
			DPRINTF("switching to %p", fds->fdset);
		} else {
			DPRINTF("first thread time %p", fds->fdset);
		}
	} else {
		DPRINTF("again for %p", fds->fdset);
		if (fd < fds->fdsize)
			return fds;
	}

	return svc_fdset_resize(fd, fds);
}

static struct svc_fdset *
svc_fdset_get_internal(int fd)
{
	if (!__isthreaded || fdsetkey == -2)
		return svc_fdset_resize(fd, &__svc_fdset);

	return svc_fdset_alloc(fd);
}


/* allow each thread to have their own copy */
void
svc_fdset_init(int flags)
{
	DPRINTF("%x", flags);
	if ((flags & SVC_FDSET_MT) && fdsetkey == -2)
		fdsetkey = -1;
}

void
svc_fdset_zero(void)
{
	DPRINTF("zero");
	struct svc_fdset *fds = svc_fdset_get_internal(0);
	memset(fds->fdset, 0, fds->fdsize);
	fds->fdmax = 0;
}

void
svc_fdset_set(int fd)
{
	struct svc_fdset *fds = svc_fdset_get_internal(fd);
	FD_SET(fd, fds->fdset);
	if (fd > fds->fdmax)
		fds->fdmax = fd;
	DPRINTF_FDSET(fds, "%d", fd);

	svc_fdset_sanitize(fds);
}

int
svc_fdset_isset(int fd)
{
	struct svc_fdset *fds = svc_fdset_get_internal(fd);
	svc_fdset_sanitize(fds);
	DPRINTF_FDSET(fds, "%d", fd);
	return FD_ISSET(fd, fds->fdset);
}

void
svc_fdset_clr(int fd)
{
	struct svc_fdset *fds = svc_fdset_get_internal(fd);
	FD_CLR(fd, fds->fdset);
	svc_fdset_sanitize(fds);
	DPRINTF_FDSET(fds, "%d", fd);
}

fd_set *
svc_fdset_copy(const fd_set *orig)
{
	int size = svc_fdset_getsize(0);
	fd_set *copy = calloc(1, __NFD_BYTES(size));
	if (copy == NULL)
		return NULL;
	if (orig)
		memcpy(copy, orig, __NFD_BYTES(size));
	return copy;
}

fd_set *
svc_fdset_get(void)
{
	struct svc_fdset *fds = svc_fdset_get_internal(0);
	svc_fdset_sanitize(fds);

	DPRINTF_FDSET(fds, "get");
	return fds->fdset;
}

int *
svc_fdset_getmax(void)
{
	struct svc_fdset *fds;

	if (!__isthreaded || fdsetkey == -2) {
		svc_fdset_sanitize(&__svc_fdset);
		return &__svc_fdset.fdmax;
	}
		
	fds = svc_fdset_alloc(0);
	if (fds == NULL)
		return NULL;
	return &fds->fdmax;
}

int
svc_fdset_getsize(int fd)
{
	struct svc_fdset *fds;

	if (!__isthreaded || fdsetkey == -2) {
		if (svc_fdset_resize(fd, &__svc_fdset) == NULL)
			return -1;
		else
			return __svc_fdset.fdsize;
	}

	fds = svc_fdset_alloc(fd);
	if (fds == NULL)
		return -1;
	return fds->fdsize;
}