asmlinkage long sys_poll(struct pollfd * ufds, unsigned int nfds, long timeout)
{
int i, j, fdcount, err;
struct pollfd **fds;
poll_table table, *wait;
int nchunks, nleft;
/* Do a sanity check on nfds ... */
if (nfds > current->files->max_fdset && nfds > OPEN_MAX)
return -EINVAL;
if (timeout) {
/* Careful about overflow in the intermediate values */
if ((unsigned long) timeout < MAX_SCHEDULE_TIMEOUT / HZ)
timeout = (unsigned long)(timeout*HZ+999)/1000+1;
else /* Negative or overflow */
timeout = MAX_SCHEDULE_TIMEOUT;
}
poll_initwait(&table);
wait = &table;
if (!timeout)
wait = NULL;
err = -ENOMEM;
fds = NULL;
if (nfds != 0) {
fds = (struct pollfd **)kmalloc(
(1 + (nfds - 1) / POLLFD_PER_PAGE) * sizeof(struct pollfd *),
GFP_KERNEL);
if (fds == NULL)
goto out;
}
nchunks = 0;
nleft = nfds;
while (nleft > POLLFD_PER_PAGE) { /* allocate complete PAGE_SIZE chunks */
fds[nchunks] = (struct pollfd *)__get_free_page(GFP_KERNEL);
if (fds[nchunks] == NULL)
goto out_fds;
nchunks++;
nleft -= POLLFD_PER_PAGE;
}
if (nleft) { /* allocate last PAGE_SIZE chunk, only nleft elements used */
fds[nchunks] = (struct pollfd *)__get_free_page(GFP_KERNEL);
if (fds[nchunks] == NULL)
goto out_fds;
}
err = -EFAULT;
for (i=0; i < nchunks; i++)
if (copy_from_user(fds[i], ufds + i*POLLFD_PER_PAGE, PAGE_SIZE))
goto out_fds1;
if (nleft) {
if (copy_from_user(fds[nchunks], ufds + nchunks*POLLFD_PER_PAGE,
nleft * sizeof(struct pollfd)))
goto out_fds1;
}
fdcount = do_poll(nfds, nchunks, nleft, fds, wait, timeout);
/* OK, now copy the revents fields back to user space. */
for(i=0; i < nchunks; i++)
for (j=0; j < POLLFD_PER_PAGE; j++, ufds++)
__put_user((fds[i] + j)->revents, &ufds->revents);
if (nleft)
for (j=0; j < nleft; j++, ufds++)
__put_user((fds[nchunks] + j)->revents, &ufds->revents);
err = fdcount;
if (!fdcount && signal_pending(current))
err = -EINTR;
out_fds1:
if (nleft)
free_page((unsigned long)(fds[nchunks]));
out_fds:
for (i=0; i < nchunks; i++)
free_page((unsigned long)(fds[i]));
if (nfds != 0)
kfree(fds);
out:
poll_freewait(&table);
return err;
}
asmlinkage long sys_poll(struct pollfd __user * ufds, unsigned int nfds, long timeout)
{
struct poll_wqueues table;
int fdcount, err;
unsigned int i;
struct poll_list *head;
struct poll_list *walk;
/* Do a sanity check on nfds ... */
if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
return -EINVAL;
if (timeout) {
/* Careful about overflow in the intermediate values */
if ((unsigned long) timeout < MAX_SCHEDULE_TIMEOUT / HZ)
timeout = (unsigned long)(timeout*HZ+999)/1000+1;
else /* Negative or overflow */
timeout = MAX_SCHEDULE_TIMEOUT;
}
poll_initwait(&table);
head = NULL;
walk = NULL;
i = nfds;
err = -ENOMEM;
while(i!=0) {
struct poll_list *pp;
pp = kmalloc(sizeof(struct poll_list)+
sizeof(struct pollfd)*
(i>POLLFD_PER_PAGE?POLLFD_PER_PAGE:i),
GFP_KERNEL);
if(pp==NULL)
goto out_fds;
pp->next=NULL;
pp->len = (i>POLLFD_PER_PAGE?POLLFD_PER_PAGE:i);
if (head == NULL)
head = pp;
else
walk->next = pp;
walk = pp;
if (copy_from_user(pp->entries, ufds + nfds-i,
sizeof(struct pollfd)*pp->len)) {
err = -EFAULT;
goto out_fds;
}
i -= pp->len;
}
fdcount = do_poll(nfds, head, &table, timeout);
/* OK, now copy the revents fields back to user space. */
walk = head;
err = -EFAULT;
while(walk != NULL) {
struct pollfd *fds = walk->entries;
int j;
for (j=0; j < walk->len; j++, ufds++) {
if(__put_user(fds[j].revents, &ufds->revents))
goto out_fds;
}
walk = walk->next;
}
err = fdcount;
if (!fdcount && signal_pending(current))
err = -EINTR;
out_fds:
walk = head;
while(walk!=NULL) {
struct poll_list *pp = walk->next;
kfree(walk);
walk = pp;
}
poll_freewait(&table);
return err;
}
