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sndio/aucat/file.c

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/* $OpenBSD: file.c,v 1.21 2010/07/10 12:32:45 ratchov Exp $ */
/*
* Copyright (c) 2008 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. If a read() or write() syscall return EAGAIN
* (operation will block), then the file is marked as "for polling", else
* the file is not polled again.
*
* the module also provides trivial timeout implementation,
* derived from:
*
* anoncvs@moule.caoua.org:/cvs
*
* midish/timo.c rev 1.16
* midish/mdep.c rev 1.69
*
* 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 timout that has expired
*
*/
#include <sys/types.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include "abuf.h"
#include "aproc.h"
#include "conf.h"
#include "file.h"
#ifdef DEBUG
#include "dbg.h"
#endif
#define MAXFDS 100
#define TIMER_USEC 10000
struct timespec file_ts;
struct filelist file_list;
struct timo *timo_queue;
unsigned timo_abstime;
/*
* 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 delta)
{
struct timo **i;
unsigned val;
int diff;
#ifdef DEBUG
if (o->set) {
dbg_puts("timo_add: already set\n");
dbg_panic();
}
if (delta == 0) {
dbg_puts("timo_add: zero timeout is evil\n");
dbg_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
if (debug_level >= 4)
dbg_puts("timo_del: not found\n");
#endif
}
/*
* routine to be called by the timer when 'delta' 24-th of microsecond
* elapsed. This routine updates time referece used by timeouts and
* calls expired timeouts
*/
void
timo_update(unsigned 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) {
dbg_puts("timo_done: timo_queue not empty!\n");
dbg_panic();
}
#endif
timo_queue = (struct timo *)0xdeadbeef;
}
#ifdef DEBUG
void
file_dbg(struct file *f)
{
dbg_puts(f->ops->name);
dbg_puts("(");
dbg_puts(f->name);
dbg_puts("|");
if (f->state & FILE_ROK)
dbg_puts("r");
if (f->state & FILE_RINUSE)
dbg_puts("R");
if (f->state & FILE_WOK)
dbg_puts("w");
if (f->state & FILE_WINUSE)
dbg_puts("W");
if (f->state & FILE_EOF)
dbg_puts("e");
if (f->state & FILE_HUP)
dbg_puts("h");
if (f->state & FILE_ZOMB)
dbg_puts("Z");
dbg_puts(")");
}
#endif
struct file *
file_new(struct fileops *ops, char *name, unsigned nfds)
{
struct file *f;
LIST_FOREACH(f, &file_list, entry)
nfds += f->ops->nfds(f);
if (nfds > MAXFDS) {
#ifdef DEBUG
if (debug_level >= 1) {
dbg_puts(name);
dbg_puts(": too many polled files\n");
}
#endif
return NULL;
}
f = malloc(ops->size);
if (f == NULL)
err(1, "file_new: %s", ops->name);
f->ops = ops;
f->name = name;
f->state = 0;
f->cycles = 0;
f->rproc = NULL;
f->wproc = NULL;
LIST_INSERT_HEAD(&file_list, f, entry);
#ifdef DEBUG
if (debug_level >= 3) {
file_dbg(f);
dbg_puts(": created\n");
}
#endif
return f;
}
void
file_del(struct file *f)
{
#ifdef DEBUG
if (debug_level >= 3) {
file_dbg(f);
dbg_puts(": terminating...\n");
}
#endif
if (f->state & (FILE_RINUSE | FILE_WINUSE)) {
f->state |= FILE_ZOMB;
} else {
LIST_REMOVE(f, entry);
#ifdef DEBUG
if (debug_level >= 3) {
file_dbg(f);
dbg_puts(": destroyed\n");
}
#endif
f->ops->close(f);
free(f);
}
}
int
file_poll(void)
{
nfds_t nfds, n;
short events, revents;
struct pollfd pfds[MAXFDS];
struct file *f, *fnext;
struct aproc *p;
struct timespec ts;
long delta_nsec;
if (LIST_EMPTY(&file_list)) {
#ifdef DEBUG
if (debug_level >= 3)
dbg_puts("nothing to do...\n");
#endif
return 0;
}
/*
* Fill the pfds[] array with files that are blocked on reading
* and/or writing, skipping those that are just waiting.
*/
#ifdef DEBUG
dbg_flush();
if (debug_level >= 4)
dbg_puts("poll:");
#endif
nfds = 0;
LIST_FOREACH(f, &file_list, entry) {
events = 0;
if (f->rproc && !(f->state & FILE_ROK))
events |= POLLIN;
if (f->wproc && !(f->state & FILE_WOK))
events |= POLLOUT;
#ifdef DEBUG
if (debug_level >= 4) {
dbg_puts(" ");
file_dbg(f);
}
#endif
n = f->ops->pollfd(f, pfds + nfds, events);
if (n == 0) {
f->pfd = NULL;
continue;
}
f->pfd = pfds + nfds;
nfds += n;
}
#ifdef DEBUG
if (debug_level >= 4) {
dbg_puts("\npfds[] =");
for (n = 0; n < nfds; n++) {
dbg_puts(" ");
dbg_putx(pfds[n].events);
}
dbg_puts("\n");
}
#endif
if (nfds > 0) {
if (poll(pfds, nfds, -1) < 0) {
if (errno == EINTR)
return 1;
err(1, "file_poll: poll failed");
}
clock_gettime(CLOCK_MONOTONIC, &ts);
delta_nsec = 1000000000L * (ts.tv_sec - file_ts.tv_sec);
delta_nsec += ts.tv_nsec - file_ts.tv_nsec;
if (delta_nsec > 0) {
file_ts = ts;
timo_update(delta_nsec / 1000);
}
}
f = LIST_FIRST(&file_list);
while (f != LIST_END(&file_list)) {
if (f->pfd == NULL) {
f = LIST_NEXT(f, entry);
continue;
}
revents = f->ops->revents(f, f->pfd);
#ifdef DEBUG
if (revents) {
f->cycles++;
if (f->cycles > FILE_MAXCYCLES) {
file_dbg(f);
dbg_puts(": busy loop, disconnecting\n");
revents = POLLHUP;
}
}
#endif
if (!(f->state & FILE_ZOMB) && (revents & POLLIN)) {
revents &= ~POLLIN;
#ifdef DEBUG
if (debug_level >= 4) {
file_dbg(f);
dbg_puts(": rok\n");
}
#endif
f->state |= FILE_ROK;
f->state |= FILE_RINUSE;
for (;;) {
p = f->rproc;
if (!p)
break;
#ifdef DEBUG
if (debug_level >= 4) {
aproc_dbg(p);
dbg_puts(": in\n");
}
#endif
if (!p->ops->in(p, NULL))
break;
}
f->state &= ~FILE_RINUSE;
}
if (!(f->state & FILE_ZOMB) && (revents & POLLOUT)) {
revents &= ~POLLOUT;
#ifdef DEBUG
if (debug_level >= 4) {
file_dbg(f);
dbg_puts(": wok\n");
}
#endif
f->state |= FILE_WOK;
f->state |= FILE_WINUSE;
for (;;) {
p = f->wproc;
if (!p)
break;
#ifdef DEBUG
if (debug_level >= 4) {
aproc_dbg(p);
dbg_puts(": out\n");
}
#endif
if (!p->ops->out(p, NULL))
break;
}
f->state &= ~FILE_WINUSE;
}
if (!(f->state & FILE_ZOMB) && (revents & POLLHUP)) {
#ifdef DEBUG
if (debug_level >= 3) {
file_dbg(f);
dbg_puts(": disconnected\n");
}
#endif
f->state |= (FILE_EOF | FILE_HUP);
}
if (!(f->state & FILE_ZOMB) && (f->state & FILE_EOF)) {
#ifdef DEBUG
if (debug_level >= 3) {
file_dbg(f);
dbg_puts(": eof\n");
}
#endif
p = f->rproc;
if (p) {
f->state |= FILE_RINUSE;
#ifdef DEBUG
if (debug_level >= 3) {
aproc_dbg(p);
dbg_puts(": eof\n");
}
#endif
p->ops->eof(p, NULL);
f->state &= ~FILE_RINUSE;
}
f->state &= ~FILE_EOF;
}
if (!(f->state & FILE_ZOMB) && (f->state & FILE_HUP)) {
#ifdef DEBUG
if (debug_level >= 3) {
file_dbg(f);
dbg_puts(": hup\n");
}
#endif
p = f->wproc;
if (p) {
f->state |= FILE_WINUSE;
#ifdef DEBUG
if (debug_level >= 3) {
aproc_dbg(p);
dbg_puts(": hup\n");
}
#endif
p->ops->hup(p, NULL);
f->state &= ~FILE_WINUSE;
}
f->state &= ~FILE_HUP;
}
fnext = LIST_NEXT(f, entry);
if (f->state & FILE_ZOMB)
file_del(f);
f = fnext;
}
if (LIST_EMPTY(&file_list)) {
#ifdef DEBUG
if (debug_level >= 3)
dbg_puts("no files anymore...\n");
#endif
return 0;
}
return 1;
}
/*
* handler for SIGALRM, invoked periodically
*/
void
file_sigalrm(int i)
{
/* nothing to do, we only want poll() to return EINTR */
}
void
filelist_init(void)
{
static struct sigaction sa;
struct itimerval it;
sigset_t set;
sigemptyset(&set);
(void)sigaddset(&set, SIGPIPE);
if (sigprocmask(SIG_BLOCK, &set, NULL))
err(1, "sigprocmask");
LIST_INIT(&file_list);
if (clock_gettime(CLOCK_MONOTONIC, &file_ts) < 0) {
perror("clock_gettime");
exit(1);
}
sa.sa_flags = SA_RESTART;
sa.sa_handler = file_sigalrm;
sigfillset(&sa.sa_mask);
if (sigaction(SIGALRM, &sa, NULL) < 0) {
perror("sigaction");
exit(1);
}
it.it_interval.tv_sec = 0;
it.it_interval.tv_usec = TIMER_USEC;
it.it_value.tv_sec = 0;
it.it_value.tv_usec = TIMER_USEC;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) {
perror("setitimer");
exit(1);
}
timo_init();
#ifdef DEBUG
dbg_sync = 0;
#endif
}
void
filelist_done(void)
{
struct itimerval it;
#ifdef DEBUG
struct file *f;
if (!LIST_EMPTY(&file_list)) {
LIST_FOREACH(f, &file_list, entry) {
file_dbg(f);
dbg_puts(" not closed\n");
}
dbg_panic();
}
dbg_sync = 1;
dbg_flush();
#endif
it.it_value.tv_sec = 0;
it.it_value.tv_usec = 0;
it.it_interval.tv_sec = 0;
it.it_interval.tv_usec = 0;
if (setitimer(ITIMER_REAL, &it, NULL) < 0) {
perror("setitimer");
exit(1);
}
timo_done();
}
unsigned
file_read(struct file *f, unsigned char *data, unsigned count)
{
unsigned n;
#ifdef DEBUG
struct timespec ts0, ts1;
long us;
if (!(f->state & FILE_ROK)) {
file_dbg(f);
dbg_puts(": read: bad state\n");
dbg_panic();
}
clock_gettime(CLOCK_MONOTONIC, &ts0);
#endif
n = f->ops->read(f, data, count);
#ifdef DEBUG
if (n > 0)
f->cycles = 0;
clock_gettime(CLOCK_MONOTONIC, &ts1);
us = 1000000L * (ts1.tv_sec - ts0.tv_sec);
us += (ts1.tv_nsec - ts0.tv_nsec) / 1000;
if (debug_level >= 4 || (debug_level >= 2 && us >= 5000)) {
dbg_puts(f->name);
dbg_puts(": read ");
dbg_putu(n);
dbg_puts(" bytes in ");
dbg_putu(us);
dbg_puts("us\n");
}
#endif
return n;
}
unsigned
file_write(struct file *f, unsigned char *data, unsigned count)
{
unsigned n;
#ifdef DEBUG
struct timespec ts0, ts1;
long us;
if (!(f->state & FILE_WOK)) {
file_dbg(f);
dbg_puts(": write: bad state\n");
dbg_panic();
}
clock_gettime(CLOCK_MONOTONIC, &ts0);
#endif
n = f->ops->write(f, data, count);
#ifdef DEBUG
if (n > 0)
f->cycles = 0;
clock_gettime(CLOCK_MONOTONIC, &ts1);
us = 1000000L * (ts1.tv_sec - ts0.tv_sec);
us += (ts1.tv_nsec - ts0.tv_nsec) / 1000;
if (debug_level >= 4 || (debug_level >= 2 && us >= 5000)) {
dbg_puts(f->name);
dbg_puts(": wrote ");
dbg_putu(n);
dbg_puts(" bytes in ");
dbg_putu(us);
dbg_puts("us\n");
}
#endif
return n;
}
void
file_eof(struct file *f)
{
struct aproc *p;
#ifdef DEBUG
if (debug_level >= 3) {
file_dbg(f);
dbg_puts(": eof requested\n");
}
#endif
if (!(f->state & (FILE_RINUSE | FILE_WINUSE))) {
p = f->rproc;
if (p) {
f->state |= FILE_RINUSE;
#ifdef DEBUG
if (debug_level >= 3) {
aproc_dbg(p);
dbg_puts(": eof\n");
}
#endif
p->ops->eof(p, NULL);
f->state &= ~FILE_RINUSE;
}
if (f->state & FILE_ZOMB)
file_del(f);
} else {
f->state &= ~FILE_ROK;
f->state |= FILE_EOF;
}
}
void
file_hup(struct file *f)
{
struct aproc *p;
#ifdef DEBUG
if (debug_level >= 3) {
file_dbg(f);
dbg_puts(": hup requested\n");
}
#endif
if (!(f->state & (FILE_RINUSE | FILE_WINUSE))) {
p = f->wproc;
if (p) {
f->state |= FILE_WINUSE;
#ifdef DEBUG
if (debug_level >= 3) {
aproc_dbg(p);
dbg_puts(": hup\n");
}
#endif
p->ops->hup(p, NULL);
f->state &= ~FILE_WINUSE;
}
if (f->state & FILE_ZOMB)
file_del(f);
} else {
f->state &= ~FILE_WOK;
f->state |= FILE_HUP;
}
}
void
file_close(struct file *f)
{
struct aproc *p;
#ifdef DEBUG
if (debug_level >= 3) {
file_dbg(f);
dbg_puts(": closing\n");
}
#endif
if (f->wproc == NULL && f->rproc == NULL)
f->state |= FILE_ZOMB;
if (!(f->state & (FILE_RINUSE | FILE_WINUSE))) {
p = f->rproc;
if (p) {
f->state |= FILE_RINUSE;
#ifdef DEBUG
if (debug_level >= 3) {
aproc_dbg(p);
dbg_puts(": eof\n");
}
#endif
p->ops->eof(p, NULL);
f->state &= ~FILE_RINUSE;
}
p = f->wproc;
if (p) {
f->state |= FILE_WINUSE;
#ifdef DEBUG
if (debug_level >= 3) {
aproc_dbg(p);
dbg_puts(": hup\n");
}
#endif
p->ops->hup(p, NULL);
f->state &= ~FILE_WINUSE;
}
if (f->state & FILE_ZOMB)
file_del(f);
} else {
f->state &= ~(FILE_ROK | FILE_WOK);
f->state |= (FILE_EOF | FILE_HUP);
}
}
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