file.c

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Author : ratchov
Date : 2024-12-20 07:35:56
Hash : 7b639200
Message : sndiod: Switch to printf(3)-style logging With this change, any line is logged using a single function call (instead of one function call per logged token). This makes the sources easier to read and reduces the binary size. Debug strings that would be too difficult to produce with snprintf(3) are simplified. ok tb, dlg
usr.bin/sndiod/file.c
/*	$OpenBSD: file.c,v 1.28 2024/12/20 07:35:56 ratchov Exp $	*/
/*
 * Copyright (c) 2008-2012 Alexandre Ratchov <alex@caoua.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
/*
 * non-blocking file i/o module: each file can be read or written (or
 * both). To achieve non-blocking io, we simply use the poll() syscall
 * in an event loop and dispatch events to sub-modules.
 *
 * the module also provides trivial timeout implementation,
 * derived from:
 *
 * 	anoncvs@moule.caoua.org:/midish
 *
 *		midish/timo.c rev 1.18
 * 		midish/mdep.c rev 1.71
 *
 * A timeout is used to schedule the call of a routine (the callback)
 * there is a global list of timeouts that is processed inside the
 * event loop. Timeouts work as follows:
 *
 *	first the timo structure must be initialized with timo_set()
 *
 *	then the timeout is scheduled (only once) with timo_add()
 *
 *	if the timeout expires, the call-back is called; then it can
 *	be scheduled again if needed. It's OK to reschedule it again
 *	from the callback
 *
 *	the timeout can be aborted with timo_del(), it is OK to try to
 *	abort a timeout that has expired
 *
 */

#include <sys/types.h>

#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#include "file.h"
#include "utils.h"

#define MAXFDS 100
#define TIMER_MSEC 5

void timo_update(unsigned int);
void timo_init(void);
void timo_done(void);
int file_process(struct file *, struct pollfd *);

struct timespec file_ts;
struct file *file_list;
struct timo *timo_queue;
unsigned int timo_abstime;
int file_slowaccept = 0, file_nfds;
#ifdef DEBUG
long long file_wtime, file_utime;
#endif

/*
 * initialise a timeout structure, arguments are callback and argument
 * that will be passed to the callback
 */
void
timo_set(struct timo *o, void (*cb)(void *), void *arg)
{
	o->cb = cb;
	o->arg = arg;
	o->set = 0;
}

/*
 * schedule the callback in 'delta' 24-th of microseconds. The timeout
 * must not be already scheduled
 */
void
timo_add(struct timo *o, unsigned int delta)
{
	struct timo **i;
	unsigned int val;
	int diff;

#ifdef DEBUG
	if (o->set) {
		logx(0, "timo_add: already set");
		panic();
	}
	if (delta == 0) {
		logx(0, "timo_add: zero timeout is evil");
		panic();
	}
#endif
	val = timo_abstime + delta;
	for (i = &timo_queue; *i != NULL; i = &(*i)->next) {
		diff = (*i)->val - val;
		if (diff > 0) {
			break;
		}
	}
	o->set = 1;
	o->val = val;
	o->next = *i;
	*i = o;
}

/*
 * abort a scheduled timeout
 */
void
timo_del(struct timo *o)
{
	struct timo **i;

	for (i = &timo_queue; *i != NULL; i = &(*i)->next) {
		if (*i == o) {
			*i = o->next;
			o->set = 0;
			return;
		}
	}
#ifdef DEBUG
	logx(4, "timo_del: not found");
#endif
}

/*
 * routine to be called by the timer when 'delta' 24-th of microsecond
 * elapsed. This routine updates time reference used by timeouts and
 * calls expired timeouts
 */
void
timo_update(unsigned int delta)
{
	struct timo *to;
	int diff;

	/*
	 * update time reference
	 */
	timo_abstime += delta;

	/*
	 * remove from the queue and run expired timeouts
	 */
	while (timo_queue != NULL) {
		/*
		 * there is no overflow here because + and - are
		 * modulo 2^32, they are the same for both signed and
		 * unsigned integers
		 */
		diff = timo_queue->val - timo_abstime;
		if (diff > 0)
			break;
		to = timo_queue;
		timo_queue = to->next;
		to->set = 0;
		to->cb(to->arg);
	}
}

/*
 * initialize timeout queue
 */
void
timo_init(void)
{
	timo_queue = NULL;
	timo_abstime = 0;
}

/*
 * destroy timeout queue
 */
void
timo_done(void)
{
#ifdef DEBUG
	if (timo_queue != NULL) {
		logx(0, "timo_done: timo_queue not empty!");
		panic();
	}
#endif
	timo_queue = (struct timo *)0xdeadbeef;
}

struct file *
file_new(struct fileops *ops, void *arg, char *name, unsigned int nfds)
{
	struct file *f;

	if (file_nfds + nfds > MAXFDS) {
#ifdef DEBUG
		logx(1, "%s: too many polled files", name);
#endif
		return NULL;
	}
	f = xmalloc(sizeof(struct file));
	f->max_nfds = nfds;
	f->nfds = 0;
	f->ops = ops;
	f->arg = arg;
	f->name = name;
	f->state = FILE_INIT;
	f->next = file_list;
	file_list = f;
#ifdef DEBUG
	logx(3, "%s: created", f->name);
#endif
	file_nfds += f->max_nfds;
	return f;
}

void
file_del(struct file *f)
{
#ifdef DEBUG
	if (f->state == FILE_ZOMB) {
		logx(0, "%s: %s: bad state in file_del", __func__, f->name);
		panic();
	}
#endif
	file_nfds -= f->max_nfds;
	f->state = FILE_ZOMB;
#ifdef DEBUG
	logx(3, "%s: destroyed", f->name);
#endif
}

int
file_process(struct file *f, struct pollfd *pfd)
{
	int rc, revents;
#ifdef DEBUG
	struct timespec ts0, ts1;
	long us;
#endif

#ifdef DEBUG
	if (log_level >= 3)
		clock_gettime(CLOCK_UPTIME, &ts0);
#endif
	rc = 0;
	revents = (f->state != FILE_ZOMB) ?
	    f->ops->revents(f->arg, pfd) : 0;
	if ((revents & POLLHUP) && (f->state != FILE_ZOMB)) {
		f->ops->hup(f->arg);
		rc = 1;
	}
	if ((revents & POLLIN) && (f->state != FILE_ZOMB)) {
		f->ops->in(f->arg);
		rc = 1;
	}
	if ((revents & POLLOUT) && (f->state != FILE_ZOMB)) {
		f->ops->out(f->arg);
		rc = 1;
	}
#ifdef DEBUG
	if (log_level >= 3) {
		clock_gettime(CLOCK_UPTIME, &ts1);
		us = 1000000L * (ts1.tv_sec - ts0.tv_sec);
		us += (ts1.tv_nsec - ts0.tv_nsec) / 1000;
		if (us >= 5000)
			logx(4, "%s: processed in %luus", f->name, us);
	}
#endif
	return rc;
}

#ifdef DEBUG
size_t
filelist_fmt(char *buf, size_t size, struct pollfd *pfd, int ret)
{
	struct file *f;
	char *p = buf, *end = buf + size;
	const char *sep = "";
	int i;

	for (f = file_list; f != NULL; f = f->next) {
		p += snprintf(p, p < end ? end - p : 0, "%s%s:", sep, f->name);
		for (i = 0; i < f->nfds; i++) {
			p += snprintf(p, p < end ? end - p : 0, " 0x%x",
			    ret ? pfd->revents : pfd->events);
			pfd++;
		}
		sep = ", ";
	}
	return p - buf;
}
#endif

int
file_poll(void)
{
	struct pollfd pfds[MAXFDS], *pfd;
	struct file *f, **pf;
	struct timespec ts;
#ifdef DEBUG
	struct timespec sleepts;
	char str[128];
#endif
	long long delta_nsec;
	int nfds, res, timo;

	/*
	 * cleanup zombies
	 */
	pf = &file_list;
	while ((f = *pf) != NULL) {
		if (f->state == FILE_ZOMB) {
			*pf = f->next;
			xfree(f);
		} else
			pf = &f->next;
	}

	if (file_list == NULL && timo_queue == NULL) {
#ifdef DEBUG
		logx(3, "nothing to do...");
#endif
		return 0;
	}

	/*
	 * fill pollfd structures
	 */
	nfds = 0;
	for (f = file_list; f != NULL; f = f->next) {
		f->nfds = f->ops->pollfd(f->arg, pfds + nfds);
		if (f->nfds == 0)
			continue;
		nfds += f->nfds;
	}
#ifdef DEBUG
	logx(4, "poll [%s]", (filelist_fmt(str, sizeof(str), pfds, 0), str));
#endif

	/*
	 * process files that do not rely on poll
	 */
	res = 0;
	for (f = file_list; f != NULL; f = f->next) {
		if (f->nfds > 0)
			continue;
		res |= file_process(f, NULL);
	}
	/*
	 * The processing may have changed the poll(2) conditions of
	 * other files, so restart the loop to force their poll(2) event
	 * masks to be reevaluated.
	 */
	if (res)
		return 1;

	/*
	 * Sleep. Calculate the number of milliseconds poll(2) must
	 * wait before the timo_update() needs to be called. If there are
	 * no timeouts scheduled, then call poll(2) with infinite
	 * timeout (i.e -1).
	 */
#ifdef DEBUG
	clock_gettime(CLOCK_UPTIME, &sleepts);
	file_utime += 1000000000LL * (sleepts.tv_sec - file_ts.tv_sec);
	file_utime += sleepts.tv_nsec - file_ts.tv_nsec;
#endif
	if (timo_queue != NULL) {
		timo = ((int)timo_queue->val - (int)timo_abstime) / 1000;
		if (timo < TIMER_MSEC)
			timo = TIMER_MSEC;
	} else
		timo = -1;
	log_flush();
	res = poll(pfds, nfds, timo);
	if (res == -1) {
		if (errno != EINTR) {
			logx(0, "poll failed");
			panic();
		}
		return 1;
	}

	/*
	 * run timeouts
	 */
	clock_gettime(CLOCK_UPTIME, &ts);
#ifdef DEBUG
	file_wtime += 1000000000LL * (ts.tv_sec - sleepts.tv_sec);
	file_wtime += ts.tv_nsec - sleepts.tv_nsec;
#endif
	if (timo_queue) {
		delta_nsec = 1000000000LL * (ts.tv_sec - file_ts.tv_sec);
		delta_nsec += ts.tv_nsec - file_ts.tv_nsec;
		if (delta_nsec >= 0 && delta_nsec < 60000000000LL)
			timo_update(delta_nsec / 1000);
		else
			logx(2, "out-of-bounds clock delta");
	}
	file_ts = ts;

	/*
	 * process files that rely on poll
	 */
	pfd = pfds;
	for (f = file_list; f != NULL; f = f->next) {
		if (f->nfds == 0)
			continue;
		file_process(f, pfd);
		pfd += f->nfds;
	}
	return 1;
}

void
filelist_init(void)
{
	sigset_t set;

	if (clock_gettime(CLOCK_UPTIME, &file_ts) == -1) {
		logx(0, "filelist_init: CLOCK_UPTIME unsupported");
		panic();
	}
	sigemptyset(&set);
	sigaddset(&set, SIGPIPE);
	sigprocmask(SIG_BLOCK, &set, NULL);
	file_list = NULL;
	log_sync = 0;
	timo_init();
}

void
filelist_done(void)
{
#ifdef DEBUG
	struct file *f;

	if (file_list != NULL) {
		for (f = file_list; f != NULL; f = f->next)
			logx(0, "%s: not closed", f->name);
		panic();
	}
	log_sync = 1;
	log_flush();
#endif
	timo_done();
}
IABSD.fr/src/usr.bin/sndiod/file.c

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IABSD.fr/src /usr.bin/sndiod/file.c
