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433 lines
8.9 KiB
433 lines
8.9 KiB
/*
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* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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#include <unistd.h>
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#include <stdlib.h>
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#include <termios.h>
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#include <pty.h>
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#include <signal.h>
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#include <errno.h>
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#include <string.h>
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#include <sched.h>
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#include <sys/socket.h>
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#include <sys/poll.h>
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#include "init.h"
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#include "user.h"
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#include "kern_util.h"
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#include "user_util.h"
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#include "sigio.h"
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#include "os.h"
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/* Changed during early boot */
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int pty_output_sigio = 0;
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int pty_close_sigio = 0;
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/* Used as a flag during SIGIO testing early in boot */
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static volatile int got_sigio = 0;
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void __init handler(int sig)
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{
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got_sigio = 1;
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}
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struct openpty_arg {
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int master;
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int slave;
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int err;
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};
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static void openpty_cb(void *arg)
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{
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struct openpty_arg *info = arg;
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info->err = 0;
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if(openpty(&info->master, &info->slave, NULL, NULL, NULL))
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info->err = -errno;
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}
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void __init check_one_sigio(void (*proc)(int, int))
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{
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struct sigaction old, new;
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struct openpty_arg pty = { .master = -1, .slave = -1 };
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int master, slave, err;
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initial_thread_cb(openpty_cb, &pty);
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if(pty.err){
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printk("openpty failed, errno = %d\n", -pty.err);
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return;
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}
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master = pty.master;
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slave = pty.slave;
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if((master == -1) || (slave == -1)){
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printk("openpty failed to allocate a pty\n");
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return;
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}
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/* Not now, but complain so we now where we failed. */
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err = raw(master);
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if (err < 0)
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panic("check_sigio : __raw failed, errno = %d\n", -err);
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err = os_sigio_async(master, slave);
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if(err < 0)
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panic("tty_fds : sigio_async failed, err = %d\n", -err);
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if(sigaction(SIGIO, NULL, &old) < 0)
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panic("check_sigio : sigaction 1 failed, errno = %d\n", errno);
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new = old;
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new.sa_handler = handler;
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if(sigaction(SIGIO, &new, NULL) < 0)
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panic("check_sigio : sigaction 2 failed, errno = %d\n", errno);
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got_sigio = 0;
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(*proc)(master, slave);
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os_close_file(master);
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os_close_file(slave);
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if(sigaction(SIGIO, &old, NULL) < 0)
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panic("check_sigio : sigaction 3 failed, errno = %d\n", errno);
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}
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static void tty_output(int master, int slave)
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{
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int n;
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char buf[512];
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printk("Checking that host ptys support output SIGIO...");
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memset(buf, 0, sizeof(buf));
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while(os_write_file(master, buf, sizeof(buf)) > 0) ;
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if(errno != EAGAIN)
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panic("check_sigio : write failed, errno = %d\n", errno);
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while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;
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if (got_sigio) {
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printk("Yes\n");
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pty_output_sigio = 1;
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} else if (n == -EAGAIN) {
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printk("No, enabling workaround\n");
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} else {
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panic("check_sigio : read failed, err = %d\n", n);
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}
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}
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static void tty_close(int master, int slave)
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{
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printk("Checking that host ptys support SIGIO on close...");
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os_close_file(slave);
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if(got_sigio){
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printk("Yes\n");
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pty_close_sigio = 1;
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}
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else printk("No, enabling workaround\n");
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}
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void __init check_sigio(void)
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{
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if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) &&
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(os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){
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printk("No pseudo-terminals available - skipping pty SIGIO "
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"check\n");
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return;
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}
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check_one_sigio(tty_output);
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check_one_sigio(tty_close);
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}
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/* Protected by sigio_lock(), also used by sigio_cleanup, which is an
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* exitcall.
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*/
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static int write_sigio_pid = -1;
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/* These arrays are initialized before the sigio thread is started, and
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* the descriptors closed after it is killed. So, it can't see them change.
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* On the UML side, they are changed under the sigio_lock.
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*/
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static int write_sigio_fds[2] = { -1, -1 };
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static int sigio_private[2] = { -1, -1 };
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struct pollfds {
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struct pollfd *poll;
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int size;
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int used;
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};
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/* Protected by sigio_lock(). Used by the sigio thread, but the UML thread
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* synchronizes with it.
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*/
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struct pollfds current_poll = {
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.poll = NULL,
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.size = 0,
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.used = 0
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};
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struct pollfds next_poll = {
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.poll = NULL,
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.size = 0,
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.used = 0
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};
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static int write_sigio_thread(void *unused)
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{
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struct pollfds *fds, tmp;
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struct pollfd *p;
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int i, n, respond_fd;
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char c;
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signal(SIGWINCH, SIG_IGN);
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fds = ¤t_poll;
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while(1){
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n = poll(fds->poll, fds->used, -1);
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if(n < 0){
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if(errno == EINTR) continue;
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printk("write_sigio_thread : poll returned %d, "
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"errno = %d\n", n, errno);
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}
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for(i = 0; i < fds->used; i++){
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p = &fds->poll[i];
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if(p->revents == 0) continue;
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if(p->fd == sigio_private[1]){
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n = os_read_file(sigio_private[1], &c, sizeof(c));
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if(n != sizeof(c))
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printk("write_sigio_thread : "
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"read failed, err = %d\n", -n);
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tmp = current_poll;
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current_poll = next_poll;
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next_poll = tmp;
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respond_fd = sigio_private[1];
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}
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else {
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respond_fd = write_sigio_fds[1];
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fds->used--;
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memmove(&fds->poll[i], &fds->poll[i + 1],
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(fds->used - i) * sizeof(*fds->poll));
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}
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n = os_write_file(respond_fd, &c, sizeof(c));
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if(n != sizeof(c))
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printk("write_sigio_thread : write failed, "
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"err = %d\n", -n);
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}
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}
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return 0;
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}
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static int need_poll(int n)
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{
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if(n <= next_poll.size){
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next_poll.used = n;
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return(0);
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}
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kfree(next_poll.poll);
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next_poll.poll = um_kmalloc_atomic(n * sizeof(struct pollfd));
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if(next_poll.poll == NULL){
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printk("need_poll : failed to allocate new pollfds\n");
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next_poll.size = 0;
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next_poll.used = 0;
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return(-1);
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}
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next_poll.size = n;
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next_poll.used = n;
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return(0);
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}
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/* Must be called with sigio_lock held, because it's needed by the marked
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* critical section. */
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static void update_thread(void)
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{
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unsigned long flags;
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int n;
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char c;
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flags = set_signals(0);
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n = os_write_file(sigio_private[0], &c, sizeof(c));
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if(n != sizeof(c)){
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printk("update_thread : write failed, err = %d\n", -n);
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goto fail;
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}
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n = os_read_file(sigio_private[0], &c, sizeof(c));
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if(n != sizeof(c)){
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printk("update_thread : read failed, err = %d\n", -n);
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goto fail;
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}
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set_signals(flags);
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return;
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fail:
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/* Critical section start */
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if(write_sigio_pid != -1)
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os_kill_process(write_sigio_pid, 1);
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write_sigio_pid = -1;
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os_close_file(sigio_private[0]);
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os_close_file(sigio_private[1]);
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os_close_file(write_sigio_fds[0]);
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os_close_file(write_sigio_fds[1]);
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/* Critical section end */
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set_signals(flags);
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}
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int add_sigio_fd(int fd, int read)
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{
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int err = 0, i, n, events;
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sigio_lock();
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for(i = 0; i < current_poll.used; i++){
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if(current_poll.poll[i].fd == fd)
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goto out;
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}
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n = current_poll.used + 1;
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err = need_poll(n);
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if(err)
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goto out;
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for(i = 0; i < current_poll.used; i++)
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next_poll.poll[i] = current_poll.poll[i];
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if(read) events = POLLIN;
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else events = POLLOUT;
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next_poll.poll[n - 1] = ((struct pollfd) { .fd = fd,
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.events = events,
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.revents = 0 });
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update_thread();
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out:
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sigio_unlock();
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return(err);
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}
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int ignore_sigio_fd(int fd)
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{
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struct pollfd *p;
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int err = 0, i, n = 0;
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sigio_lock();
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for(i = 0; i < current_poll.used; i++){
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if(current_poll.poll[i].fd == fd) break;
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}
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if(i == current_poll.used)
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goto out;
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err = need_poll(current_poll.used - 1);
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if(err)
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goto out;
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for(i = 0; i < current_poll.used; i++){
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p = ¤t_poll.poll[i];
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if(p->fd != fd) next_poll.poll[n++] = current_poll.poll[i];
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}
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if(n == i){
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printk("ignore_sigio_fd : fd %d not found\n", fd);
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err = -1;
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goto out;
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}
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update_thread();
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out:
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sigio_unlock();
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return(err);
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}
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static int setup_initial_poll(int fd)
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{
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struct pollfd *p;
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p = um_kmalloc_atomic(sizeof(struct pollfd));
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if(p == NULL){
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printk("setup_initial_poll : failed to allocate poll\n");
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return(-1);
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}
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*p = ((struct pollfd) { .fd = fd,
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.events = POLLIN,
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.revents = 0 });
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current_poll = ((struct pollfds) { .poll = p,
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.used = 1,
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.size = 1 });
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return(0);
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}
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void write_sigio_workaround(void)
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{
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unsigned long stack;
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int err;
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sigio_lock();
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if(write_sigio_pid != -1)
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goto out;
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err = os_pipe(write_sigio_fds, 1, 1);
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if(err < 0){
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printk("write_sigio_workaround - os_pipe 1 failed, "
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"err = %d\n", -err);
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goto out;
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}
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err = os_pipe(sigio_private, 1, 1);
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if(err < 0){
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printk("write_sigio_workaround - os_pipe 2 failed, "
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"err = %d\n", -err);
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goto out_close1;
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}
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if(setup_initial_poll(sigio_private[1]))
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goto out_close2;
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write_sigio_pid = run_helper_thread(write_sigio_thread, NULL,
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CLONE_FILES | CLONE_VM, &stack, 0);
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if(write_sigio_pid < 0) goto out_close2;
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if(write_sigio_irq(write_sigio_fds[0]))
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goto out_kill;
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out:
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sigio_unlock();
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return;
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out_kill:
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os_kill_process(write_sigio_pid, 1);
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write_sigio_pid = -1;
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out_close2:
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os_close_file(sigio_private[0]);
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os_close_file(sigio_private[1]);
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out_close1:
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os_close_file(write_sigio_fds[0]);
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os_close_file(write_sigio_fds[1]);
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sigio_unlock();
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}
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int read_sigio_fd(int fd)
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{
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int n;
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char c;
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n = os_read_file(fd, &c, sizeof(c));
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if(n != sizeof(c)){
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if(n < 0) {
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printk("read_sigio_fd - read failed, err = %d\n", -n);
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return(n);
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}
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else {
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printk("read_sigio_fd - short read, bytes = %d\n", n);
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return(-EIO);
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}
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}
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return(n);
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}
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static void sigio_cleanup(void)
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{
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if (write_sigio_pid != -1) {
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os_kill_process(write_sigio_pid, 1);
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write_sigio_pid = -1;
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}
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}
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__uml_exitcall(sigio_cleanup);
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