src/fd.c

/*
 * File descriptors management functions.
 *
 * Copyright 2000-2007 Willy Tarreau <w@1wt.eu>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 */

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>

#include <common/compat.h>
#include <common/config.h>

#include <types/fd.h>
#include <types/global.h>

#include <proto/fd.h>

struct fdtab *fdtab = NULL;     /* array of all the file descriptors */
int maxfd;                      /* # of the highest fd + 1 */
int totalconn;                  /* total # of terminated sessions */
int actconn;                    /* # of active sessions */

int cfg_polling_mechanism = 0;  /* POLL_USE_{SELECT|POLL|EPOLL} */

struct poller pollers[MAX_POLLERS];
struct poller cur_poller;
int nbpollers = 0;


/*********************
 * generic functions
 *********************/

extern int select_register(struct poller *p);
#if defined(ENABLE_POLL)
extern int poll_register(struct poller *p);
#endif
#if defined(ENABLE_EPOLL)
extern int epoll_register(struct poller *p);
#endif
#if defined(ENABLE_KQUEUE)
extern int kqueue_register(struct poller *p);
#endif


/* Deletes an FD from the fdsets, and recomputes the maxfd limit.
 * The file descriptor is also closed.
 */
void fd_delete(int fd)
{
	EV_FD_CLO(fd);
	close(fd);
	fdtab[fd].state = FD_STCLOSE;

	while ((maxfd-1 >= 0) && (fdtab[maxfd-1].state == FD_STCLOSE))
		maxfd--;
}


/* registers all known pollers */
void register_pollers()
{
	if (select_register(&pollers[nbpollers]))
		nbpollers++;
#if defined(ENABLE_POLL)
	poll_register(&pollers[nbpollers]);
	nbpollers++;
#endif

#if defined(ENABLE_EPOLL)
	epoll_register(&pollers[nbpollers]);
	nbpollers++;
#endif

#if defined(ENABLE_KQUEUE)
	kqueue_register(&pollers[nbpollers]);
	nbpollers++;
#endif
}

/* disable the specified poller */
void disable_poller(const char *poller_name)
{
	int p;

	for (p = 0; p < nbpollers; p++)
		if (strcmp(pollers[p].name, poller_name) == 0)
			pollers[p].pref = 0;
}

/*
 * Initialize the pollers till the best one is found.
 * If none works, returns 0, otherwise 1.
 */
int init_pollers()
{
	int p;
	struct poller *bp;


	do {
		bp = NULL;
		for (p = 0; p < nbpollers; p++)
			if (!bp || (pollers[p].pref > bp->pref))
				bp = &pollers[p];

		if (!bp || bp->pref == 0)
			break;

		if (bp->init(bp)) {
			memcpy(&cur_poller, bp, sizeof(*bp));
			return 1;
		}
	} while (!bp || bp->pref == 0);
	return 0;
}

/*
 * Lists the known pollers on <out>.
 * Should be performed only before initialization.
 */
int list_pollers(FILE *out)
{
	int p;
	int last, next;
	int usable;
	struct poller *bp;

	fprintf(out, "Available polling systems :\n");

	usable = 0;
	bp = NULL;
	last = next = -1;
	while (1) {
		for (p = 0; p < nbpollers; p++) {
			if (!bp || (pollers[p].pref > bp->pref))
				bp = &pollers[p];
			if ((next < 0 || pollers[p].pref > next)
			    && (last < 0 || pollers[p].pref < last))
				next = pollers[p].pref;
		}

		if (next == -1)
			break;

		for (p = 0; p < nbpollers; p++) {
			if (pollers[p].pref == next) {
				fprintf(out, " %10s : ", pollers[p].name);
				if (pollers[p].pref == 0)
					fprintf(out, "disabled, ");
				else
					fprintf(out, "pref=%3d, ", pollers[p].pref);
				if (pollers[p].test(&pollers[p])) {
					fprintf(out, " test result OK");
					if (next > 0)
						usable++;
				} else
					fprintf(out, " test result FAILED");
				fprintf(out, "\n");
			}
		}
		last = next;
		next = -1;
	};
	fprintf(out, "Total: %d (%d usable), will use %s.\n", nbpollers, usable, bp ? bp->name : "none");
	return 0;
}

/*
 * Some pollers may lose their connection after a fork(). It may be necessary
 * to create initialize part of them again. Returns 0 in case of failure,
 * otherwise 1. The fork() function may be NULL if unused. In case of error,
 * the the current poller is destroyed and the caller is responsible for trying
 * another one by calling init_pollers() again.
 */
int fork_poller()
{
	if (cur_poller.fork) {
		if (cur_poller.fork(&cur_poller))
			return 1;
		cur_poller.term(&cur_poller);
		return 0;
	}
	return 1;
}

/*
 * Local variables:
 *  c-indent-level: 8
 *  c-basic-offset: 8
 * End:
 */