344 lines
7.4 KiB
C
344 lines
7.4 KiB
C
/*
|
|
* Copyright (c) 1992, 1993, 1996
|
|
* Berkeley Software Design, Inc. All rights reserved.
|
|
*
|
|
* 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.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by Berkeley Software
|
|
* Design, Inc.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``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 Berkeley Software Design, Inc. 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.
|
|
*
|
|
* BSDI AsyncIO.c,v 2.2 1996/04/08 19:32:10 bostic Exp
|
|
*/
|
|
#include <stdio.h>
|
|
#include <sys/param.h>
|
|
#include <sys/types.h>
|
|
#include <fcntl.h>
|
|
#include <sys/time.h>
|
|
#include <signal.h>
|
|
#include <errno.h>
|
|
#include <limits.h>
|
|
#include "doscmd.h"
|
|
|
|
#define FD_ISZERO(p) ((p)->fds_bits[0] == 0)
|
|
|
|
/*
|
|
* Set or Clear the Async nature of an FD
|
|
*/
|
|
|
|
#define SETASYNC(fd) fcntl(fd, F_SETFL, handlers[fd].flag | FASYNC)
|
|
#define CLRASYNC(fd) fcntl(fd, F_SETFL, handlers[fd].flag & ~FASYNC)
|
|
|
|
/*
|
|
* Request that ``func'' be called everytime data is available on ``fd''
|
|
*/
|
|
|
|
static fd_set fdset = { 0 }; /* File Descriptors to select on */
|
|
|
|
typedef struct {
|
|
void (*func)(void *, REGISTERS);
|
|
/* Function to call when data arrives */
|
|
void (*failure)(void *); /* Function to call on failure */
|
|
void *arg; /* Argument to above functions */
|
|
int lockcnt; /* Nested level of lock */
|
|
fd_set members; /* Set of FD's to disable on SIGIO */
|
|
int flag; /* The flag from F_GETFL (we own it) */
|
|
} Async;
|
|
|
|
static Async handlers[OPEN_MAX];
|
|
|
|
static void HandleIO (struct sigframe *sf);
|
|
|
|
static int in_handler = 0;
|
|
|
|
void
|
|
_RegisterIO(fd, func, arg, failure)
|
|
int fd;
|
|
void (*func)();
|
|
void *arg;
|
|
void (*failure)();
|
|
{
|
|
static int firsttime = 1;
|
|
Async *as;
|
|
|
|
if (fd < 0 || fd > OPEN_MAX) {
|
|
printf("%d: Invalid FD\n", fd);
|
|
return;
|
|
}
|
|
|
|
as = &handlers[fd];
|
|
|
|
if ((as->flag = fcntl(fd, F_GETFL, 0)) == -1) {
|
|
if (func) {
|
|
/*@*/ perror("get fcntl");
|
|
/*@*/ abort();
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (firsttime) {
|
|
struct sigaction sa;
|
|
|
|
firsttime = 0;
|
|
setsignal(SIGIO, HandleIO);
|
|
}
|
|
|
|
if (handlers[fd].func = func) {
|
|
as->lockcnt = 0;
|
|
as->arg = arg;
|
|
as->failure = failure;
|
|
|
|
FD_SET(fd, &fdset);
|
|
FD_ZERO(&handlers[fd].members);
|
|
FD_SET(fd, &handlers[fd].members);
|
|
if (fcntl(fd, F_SETOWN, getpid()) < 0) {
|
|
/*@*/ perror("SETOWN");
|
|
}
|
|
SETASYNC(fd);
|
|
} else {
|
|
as->arg = 0;
|
|
as->failure = 0;
|
|
as->lockcnt = 0;
|
|
|
|
CLRASYNC(fd);
|
|
FD_CLR(fd, &fdset);
|
|
}
|
|
}
|
|
|
|
static void
|
|
CleanIO()
|
|
{
|
|
int x;
|
|
static struct timeval tv = { 0 };
|
|
|
|
/*
|
|
* For every file des in fd_set, we check to see if it
|
|
* causes a fault on select(). If so, we unregister it
|
|
* for the user.
|
|
*/
|
|
for (x = 0; x < OPEN_MAX; ++x) {
|
|
fd_set set;
|
|
|
|
if (!FD_ISSET(x, &fdset))
|
|
continue;
|
|
|
|
FD_ZERO(&set);
|
|
FD_SET(x, &set);
|
|
errno = 0;
|
|
if (select(FD_SETSIZE, &set, 0, 0, &tv) < 0 &&
|
|
errno == EBADF) {
|
|
void (*f)();
|
|
void *a;
|
|
printf("Closed file descriptor %d\n", x);
|
|
|
|
f = handlers[x].failure;
|
|
a = handlers[x].arg;
|
|
handlers[x].failure = 0;
|
|
handlers[x].func = 0;
|
|
handlers[x].arg = 0;
|
|
handlers[x].lockcnt = 0;
|
|
FD_CLR(x, &fdset);
|
|
if (f)
|
|
(*f)(a);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
HandleIO(struct sigframe *sf)
|
|
{
|
|
++in_handler;
|
|
|
|
for (;;) {
|
|
static struct timeval tv = { 0 };
|
|
fd_set readset;
|
|
int x;
|
|
int fd;
|
|
|
|
readset = fdset;
|
|
if ((x = select(FD_SETSIZE, &readset, 0, 0, &tv)) < 0) {
|
|
/*
|
|
* If we failed becuase of a BADFiledes, go find
|
|
* which one(s), fail them out and then try a
|
|
* new select to see if any of the good ones are
|
|
* okay.
|
|
*/
|
|
if (errno == EBADF) {
|
|
CleanIO();
|
|
if (FD_ISZERO(&fdset))
|
|
break;
|
|
continue;
|
|
}
|
|
perror("select");
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* If we run out of fds to look at, break out of the loop
|
|
* and exit the handler.
|
|
*/
|
|
if (!x)
|
|
break;
|
|
|
|
/*
|
|
* If there is at least 1 fd saying it has something for
|
|
* us, then loop through the sets looking for those
|
|
* bits, stopping when we have handleed the number it has
|
|
* asked for.
|
|
*/
|
|
for (fd = 0; x && fd < OPEN_MAX; ++fd) {
|
|
Async *as;
|
|
|
|
if (!FD_ISSET(fd, &readset)) {
|
|
continue;
|
|
}
|
|
--x;
|
|
|
|
/*
|
|
* Is suppose it is possible that one of the previous
|
|
* io requests changed the fdset.
|
|
* We do know that SIGIO is turned off right now,
|
|
* so it is safe to checkit.
|
|
*/
|
|
if (!FD_ISSET(fd, &fdset)) {
|
|
continue;
|
|
}
|
|
as = &handlers[fd];
|
|
|
|
/*
|
|
* as in above, maybe someone locked us...
|
|
* we are in dangerous water now if we are
|
|
* multi-tasked
|
|
*/
|
|
if (as->lockcnt) {
|
|
/*@*/ fprintf(stderr, "Selected IO on locked %d\n",fd);
|
|
continue;
|
|
}
|
|
/*
|
|
* Okay, now if there exists a handler, we should
|
|
* call it. We must turn back on SIGIO if there
|
|
* are possibly other people waiting for it.
|
|
*/
|
|
if (as->func) {
|
|
int afd;
|
|
Async *aas;
|
|
|
|
/*
|
|
* STEP 1: Lock out all "members"
|
|
*/
|
|
aas = handlers;
|
|
if (0)
|
|
for (afd = 0; afd < OPEN_MAX; ++afd, ++aas) {
|
|
if (FD_ISSET(afd, &as->members)) {
|
|
if (aas->func) {
|
|
if (as->lockcnt++ == 0) {
|
|
FD_CLR(afd, &fdset);
|
|
CLRASYNC(afd);
|
|
}
|
|
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* STEP 2: Renable SIGIO so other FDs can
|
|
* use a hit.
|
|
_UnblockIO();
|
|
*/
|
|
|
|
/*
|
|
* STEP 3: Call the handler
|
|
*/
|
|
(*handlers[fd].func)(handlers[fd].arg,
|
|
&sf->sf_siginfo.si_sc);
|
|
|
|
/*
|
|
* STEP 4: Just turn SIGIO off. No check.
|
|
_BlockIO();
|
|
*/
|
|
|
|
/*
|
|
* STEP 5: Unlock all "members"
|
|
*/
|
|
aas = handlers;
|
|
if (0)
|
|
for (afd = 0; afd < OPEN_MAX; ++afd, ++aas) {
|
|
if (FD_ISSET(afd, &as->members)) {
|
|
if (aas->func) {
|
|
if (--as->lockcnt == 0) {
|
|
FD_SET(afd, &fdset);
|
|
SETASYNC(afd);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
/*
|
|
* Otherwise deregister this guy.
|
|
*/
|
|
_RegisterIO(fd, 0, 0, 0);
|
|
}
|
|
}
|
|
/*
|
|
* If we did not process all the fd's, then we should
|
|
* break out of the probable infinite loop.
|
|
*/
|
|
if (x) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
--in_handler;
|
|
}
|
|
|
|
static int stackp = 0;
|
|
|
|
void
|
|
_BlockIO()
|
|
{
|
|
sigset_t set;
|
|
|
|
if (stackp >= 64) {
|
|
fprintf(stderr, "Signal stack count too deep\n");
|
|
abort();
|
|
}
|
|
if (stackp++ == 0) {
|
|
sigaddset(&set, SIGIO);
|
|
sigprocmask(SIG_BLOCK, &set, 0);
|
|
}
|
|
}
|
|
|
|
void
|
|
_UnblockIO()
|
|
{
|
|
sigset_t set;
|
|
|
|
if (stackp <= 0) {
|
|
fprintf(stderr, "Negative signal stack count\n");
|
|
abort();
|
|
}
|
|
if (--stackp == 0) {
|
|
sigaddset(&set, SIGIO);
|
|
sigprocmask(SIG_UNBLOCK, &set, 0);
|
|
}
|
|
}
|