324 lines
6.7 KiB
C
324 lines
6.7 KiB
C
/*
|
|
* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
|
|
* Licensed under the GPL
|
|
*/
|
|
|
|
#include <unistd.h>
|
|
#include <stdlib.h>
|
|
#include <termios.h>
|
|
#include <pty.h>
|
|
#include <signal.h>
|
|
#include <errno.h>
|
|
#include <string.h>
|
|
#include <sched.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/poll.h>
|
|
#include "init.h"
|
|
#include "user.h"
|
|
#include "kern_util.h"
|
|
#include "user_util.h"
|
|
#include "sigio.h"
|
|
#include "os.h"
|
|
|
|
/* Protected by sigio_lock(), also used by sigio_cleanup, which is an
|
|
* exitcall.
|
|
*/
|
|
static int write_sigio_pid = -1;
|
|
|
|
/* These arrays are initialized before the sigio thread is started, and
|
|
* the descriptors closed after it is killed. So, it can't see them change.
|
|
* On the UML side, they are changed under the sigio_lock.
|
|
*/
|
|
#define SIGIO_FDS_INIT {-1, -1}
|
|
|
|
static int write_sigio_fds[2] = SIGIO_FDS_INIT;
|
|
static int sigio_private[2] = SIGIO_FDS_INIT;
|
|
|
|
struct pollfds {
|
|
struct pollfd *poll;
|
|
int size;
|
|
int used;
|
|
};
|
|
|
|
/* Protected by sigio_lock(). Used by the sigio thread, but the UML thread
|
|
* synchronizes with it.
|
|
*/
|
|
struct pollfds current_poll = {
|
|
.poll = NULL,
|
|
.size = 0,
|
|
.used = 0
|
|
};
|
|
|
|
struct pollfds next_poll = {
|
|
.poll = NULL,
|
|
.size = 0,
|
|
.used = 0
|
|
};
|
|
|
|
static int write_sigio_thread(void *unused)
|
|
{
|
|
struct pollfds *fds, tmp;
|
|
struct pollfd *p;
|
|
int i, n, respond_fd;
|
|
char c;
|
|
|
|
signal(SIGWINCH, SIG_IGN);
|
|
fds = ¤t_poll;
|
|
while(1){
|
|
n = poll(fds->poll, fds->used, -1);
|
|
if(n < 0){
|
|
if(errno == EINTR) continue;
|
|
printk("write_sigio_thread : poll returned %d, "
|
|
"errno = %d\n", n, errno);
|
|
}
|
|
for(i = 0; i < fds->used; i++){
|
|
p = &fds->poll[i];
|
|
if(p->revents == 0) continue;
|
|
if(p->fd == sigio_private[1]){
|
|
n = os_read_file(sigio_private[1], &c, sizeof(c));
|
|
if(n != sizeof(c))
|
|
printk("write_sigio_thread : "
|
|
"read failed, err = %d\n", -n);
|
|
tmp = current_poll;
|
|
current_poll = next_poll;
|
|
next_poll = tmp;
|
|
respond_fd = sigio_private[1];
|
|
}
|
|
else {
|
|
respond_fd = write_sigio_fds[1];
|
|
fds->used--;
|
|
memmove(&fds->poll[i], &fds->poll[i + 1],
|
|
(fds->used - i) * sizeof(*fds->poll));
|
|
}
|
|
|
|
n = os_write_file(respond_fd, &c, sizeof(c));
|
|
if(n != sizeof(c))
|
|
printk("write_sigio_thread : write failed, "
|
|
"err = %d\n", -n);
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int need_poll(int n)
|
|
{
|
|
if(n <= next_poll.size){
|
|
next_poll.used = n;
|
|
return(0);
|
|
}
|
|
kfree(next_poll.poll);
|
|
next_poll.poll = um_kmalloc_atomic(n * sizeof(struct pollfd));
|
|
if(next_poll.poll == NULL){
|
|
printk("need_poll : failed to allocate new pollfds\n");
|
|
next_poll.size = 0;
|
|
next_poll.used = 0;
|
|
return(-1);
|
|
}
|
|
next_poll.size = n;
|
|
next_poll.used = n;
|
|
return(0);
|
|
}
|
|
|
|
/* Must be called with sigio_lock held, because it's needed by the marked
|
|
* critical section. */
|
|
static void update_thread(void)
|
|
{
|
|
unsigned long flags;
|
|
int n;
|
|
char c;
|
|
|
|
flags = set_signals(0);
|
|
n = os_write_file(sigio_private[0], &c, sizeof(c));
|
|
if(n != sizeof(c)){
|
|
printk("update_thread : write failed, err = %d\n", -n);
|
|
goto fail;
|
|
}
|
|
|
|
n = os_read_file(sigio_private[0], &c, sizeof(c));
|
|
if(n != sizeof(c)){
|
|
printk("update_thread : read failed, err = %d\n", -n);
|
|
goto fail;
|
|
}
|
|
|
|
set_signals(flags);
|
|
return;
|
|
fail:
|
|
/* Critical section start */
|
|
if(write_sigio_pid != -1)
|
|
os_kill_process(write_sigio_pid, 1);
|
|
write_sigio_pid = -1;
|
|
close(sigio_private[0]);
|
|
close(sigio_private[1]);
|
|
close(write_sigio_fds[0]);
|
|
close(write_sigio_fds[1]);
|
|
/* Critical section end */
|
|
set_signals(flags);
|
|
}
|
|
|
|
int add_sigio_fd(int fd, int read)
|
|
{
|
|
int err = 0, i, n, events;
|
|
|
|
sigio_lock();
|
|
for(i = 0; i < current_poll.used; i++){
|
|
if(current_poll.poll[i].fd == fd)
|
|
goto out;
|
|
}
|
|
|
|
n = current_poll.used + 1;
|
|
err = need_poll(n);
|
|
if(err)
|
|
goto out;
|
|
|
|
for(i = 0; i < current_poll.used; i++)
|
|
next_poll.poll[i] = current_poll.poll[i];
|
|
|
|
if(read) events = POLLIN;
|
|
else events = POLLOUT;
|
|
|
|
next_poll.poll[n - 1] = ((struct pollfd) { .fd = fd,
|
|
.events = events,
|
|
.revents = 0 });
|
|
update_thread();
|
|
out:
|
|
sigio_unlock();
|
|
return(err);
|
|
}
|
|
|
|
int ignore_sigio_fd(int fd)
|
|
{
|
|
struct pollfd *p;
|
|
int err = 0, i, n = 0;
|
|
|
|
sigio_lock();
|
|
for(i = 0; i < current_poll.used; i++){
|
|
if(current_poll.poll[i].fd == fd) break;
|
|
}
|
|
if(i == current_poll.used)
|
|
goto out;
|
|
|
|
err = need_poll(current_poll.used - 1);
|
|
if(err)
|
|
goto out;
|
|
|
|
for(i = 0; i < current_poll.used; i++){
|
|
p = ¤t_poll.poll[i];
|
|
if(p->fd != fd) next_poll.poll[n++] = current_poll.poll[i];
|
|
}
|
|
if(n == i){
|
|
printk("ignore_sigio_fd : fd %d not found\n", fd);
|
|
err = -1;
|
|
goto out;
|
|
}
|
|
|
|
update_thread();
|
|
out:
|
|
sigio_unlock();
|
|
return(err);
|
|
}
|
|
|
|
static struct pollfd *setup_initial_poll(int fd)
|
|
{
|
|
struct pollfd *p;
|
|
|
|
p = um_kmalloc(sizeof(struct pollfd));
|
|
if (p == NULL) {
|
|
printk("setup_initial_poll : failed to allocate poll\n");
|
|
return NULL;
|
|
}
|
|
*p = ((struct pollfd) { .fd = fd,
|
|
.events = POLLIN,
|
|
.revents = 0 });
|
|
return p;
|
|
}
|
|
|
|
void write_sigio_workaround(void)
|
|
{
|
|
unsigned long stack;
|
|
struct pollfd *p;
|
|
int err;
|
|
int l_write_sigio_fds[2];
|
|
int l_sigio_private[2];
|
|
int l_write_sigio_pid;
|
|
|
|
/* We call this *tons* of times - and most ones we must just fail. */
|
|
sigio_lock();
|
|
l_write_sigio_pid = write_sigio_pid;
|
|
sigio_unlock();
|
|
|
|
if (l_write_sigio_pid != -1)
|
|
return;
|
|
|
|
err = os_pipe(l_write_sigio_fds, 1, 1);
|
|
if(err < 0){
|
|
printk("write_sigio_workaround - os_pipe 1 failed, "
|
|
"err = %d\n", -err);
|
|
return;
|
|
}
|
|
err = os_pipe(l_sigio_private, 1, 1);
|
|
if(err < 0){
|
|
printk("write_sigio_workaround - os_pipe 2 failed, "
|
|
"err = %d\n", -err);
|
|
goto out_close1;
|
|
}
|
|
|
|
p = setup_initial_poll(l_sigio_private[1]);
|
|
if(!p)
|
|
goto out_close2;
|
|
|
|
sigio_lock();
|
|
|
|
/* Did we race? Don't try to optimize this, please, it's not so likely
|
|
* to happen, and no more than once at the boot. */
|
|
if(write_sigio_pid != -1)
|
|
goto out_free;
|
|
|
|
current_poll = ((struct pollfds) { .poll = p,
|
|
.used = 1,
|
|
.size = 1 });
|
|
|
|
if (write_sigio_irq(l_write_sigio_fds[0]))
|
|
goto out_clear_poll;
|
|
|
|
memcpy(write_sigio_fds, l_write_sigio_fds, sizeof(l_write_sigio_fds));
|
|
memcpy(sigio_private, l_sigio_private, sizeof(l_sigio_private));
|
|
|
|
write_sigio_pid = run_helper_thread(write_sigio_thread, NULL,
|
|
CLONE_FILES | CLONE_VM, &stack, 0);
|
|
|
|
if (write_sigio_pid < 0)
|
|
goto out_clear;
|
|
|
|
sigio_unlock();
|
|
return;
|
|
|
|
out_clear:
|
|
write_sigio_pid = -1;
|
|
write_sigio_fds[0] = -1;
|
|
write_sigio_fds[1] = -1;
|
|
sigio_private[0] = -1;
|
|
sigio_private[1] = -1;
|
|
out_clear_poll:
|
|
current_poll = ((struct pollfds) { .poll = NULL,
|
|
.size = 0,
|
|
.used = 0 });
|
|
out_free:
|
|
kfree(p);
|
|
sigio_unlock();
|
|
out_close2:
|
|
close(l_sigio_private[0]);
|
|
close(l_sigio_private[1]);
|
|
out_close1:
|
|
close(l_write_sigio_fds[0]);
|
|
close(l_write_sigio_fds[1]);
|
|
}
|
|
|
|
void sigio_cleanup(void)
|
|
{
|
|
if(write_sigio_pid != -1){
|
|
os_kill_process(write_sigio_pid, 1);
|
|
write_sigio_pid = -1;
|
|
}
|
|
}
|