static void __put_unused_fd(struct files_struct *files, unsigned int fd)
{
struct fdtable *fdt = files_fdtable(files);
__FD_CLR(fd, fdt->open_fds);
if (fd < files->next_fd)
files->next_fd = fd;
}
/**
* Destroy the @a xnselect structure associated with a file descriptor.
*
* Any binding with a @a xnselector block is destroyed.
*
* @param select_block pointer to the @a xnselect structure associated with a file descriptor
*/
void xnselect_destroy(struct xnselect *select_block)
{
xnholder_t *holder;
int resched;
spl_t s;
xnlock_get_irqsave(&nklock, s);
while ((holder = getq(&select_block->bindings))) {
struct xnselect_binding *binding;
struct xnselector *selector;
binding = link2binding(holder, link);
selector = binding->selector;
__FD_CLR(binding->bit_index,
&selector->fds[binding->type].expected);
if (!__FD_ISSET(binding->bit_index,
&selector->fds[binding->type].pending)) {
__FD_SET(binding->bit_index,
&selector->fds[binding->type].pending);
if (xnselect_wakeup(selector))
resched = 1;
}
removeq(&selector->bindings, &binding->slink);
xnlock_put_irqrestore(&nklock, s);
xnfree(binding);
xnlock_get_irqsave(&nklock, s);
}
if (resched)
xnpod_schedule();
xnlock_put_irqrestore(&nklock, s);
}
/* Must be called with nklock locked irqs off */
int __xnselect_signal(struct xnselect *select_block, unsigned state)
{
xnholder_t *holder;
int resched;
for(resched = 0, holder = getheadq(&select_block->bindings);
holder; holder = nextq(&select_block->bindings, holder)) {
struct xnselect_binding *binding;
struct xnselector *selector;
binding = link2binding(holder, link);
selector = binding->selector;
if (state) {
if (!__FD_ISSET(binding->bit_index,
&selector->fds[binding->type].pending)) {
__FD_SET(binding->bit_index,
&selector->fds[binding->type].pending);
if (xnselect_wakeup(selector))
resched = 1;
}
} else
__FD_CLR(binding->bit_index,
&selector->fds[binding->type].pending);
}
return resched;
}
/**
* Bind a file descriptor (represented by its @a xnselect structure) to a
* selector block.
*
* @param select_block pointer to the @a struct @a xnselect to be bound;
*
* @param binding pointer to a newly allocated (using xnmalloc) @a struct
* @a xnselect_binding;
*
* @param selector pointer to the selector structure;
*
* @param type type of events (@a XNSELECT_READ, @a XNSELECT_WRITE, or @a
* XNSELECT_EXCEPT);
*
* @param index index of the file descriptor (represented by @a select_block) in the bit fields used by the @a selector structure;
*
* @param state current state of the file descriptor>.
*
* @a select_block must have been initialized with xnselect_init(),
* the @a xnselector structure must have been initialized with
* xnselector_init(), @a binding may be uninitialized.
*
* This service must be called with nklock locked, irqs off. For this reason,
* the @a binding parameter must have been allocated by the caller outside the
* locking section.
*
* @retval -EINVAL if @a type or @a index is invalid;
* @retval 0 otherwise.
*/
int xnselect_bind(struct xnselect *select_block,
struct xnselect_binding *binding,
struct xnselector *selector,
unsigned type,
unsigned index,
unsigned state)
{
if (type >= XNSELECT_MAX_TYPES || index > __FD_SETSIZE)
return -EINVAL;
binding->selector = selector;
binding->fd = select_block;
binding->type = type;
binding->bit_index = index;
inith(&binding->link);
inith(&binding->slink);
appendq(&selector->bindings, &binding->slink);
appendq(&select_block->bindings, &binding->link);
__FD_SET(index, &selector->fds[type].expected);
if (state) {
__FD_SET(index, &selector->fds[type].pending);
if (xnselect_wakeup(selector))
xnpod_schedule();
} else
__FD_CLR(index, &selector->fds[type].pending);
return 0;
}
void fastcall __put_unused_fd(struct files_struct *files, unsigned int fd)
{
struct fdtable *fdt = files_fdtable(files);
KSTM_BUG_ON(need_files_checkpoint());
__FD_CLR(fd, fdt->open_fds);
if (fd < files->next_fd)
files->next_fd = fd;
}
static inline void __put_unused_fd(struct files_struct *files, unsigned int fd)
{
__FD_CLR(fd, files->open_fds);
if (fd < files->next_fd)
files->next_fd = fd;
}
/**
* lookup_instantiate_filp - instantiates the open intent filp
* @nd: pointer to nameidata
* @dentry: pointer to dentry
* @open: open callback
*
* Helper for filesystems that want to use lookup open intents and pass back
* a fully instantiated struct file to the caller.
* This function is meant to be called from within a filesystem's
* lookup method.
* Beware of calling it for non-regular files! Those ->open methods might block
* (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
* leading to a deadlock, as nobody can open that fifo anymore, because
* another process to open fifo will block on locked parent when doing lookup).
* Note that in case of error, nd->intent.open.file is destroyed, but the
* path information remains valid.
* If the open callback is set to NULL, then the standard f_op->open()
* filesystem callback is substituted.
*/
struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
int (*open)(struct inode *, struct file *))
{
struct path path = { .dentry = dentry, .mnt = nd->path.mnt };
const struct cred *cred = current_cred();
if (IS_ERR(nd->intent.open.file))
goto out;
if (IS_ERR(dentry))
goto out_err;
nd->intent.open.file = __dentry_open(&path, nd->intent.open.file,
open, cred);
out:
return nd->intent.open.file;
out_err:
release_open_intent(nd);
nd->intent.open.file = (struct file *)dentry;
goto out;
}
EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
/**
* nameidata_to_filp - convert a nameidata to an open filp.
* @nd: pointer to nameidata
* @flags: open flags
*
* Note that this function destroys the original nameidata
*/
struct file *nameidata_to_filp(struct nameidata *nd)
{
const struct cred *cred = current_cred();
struct file *filp;
/* Pick up the filp from the open intent */
filp = nd->intent.open.file;
nd->intent.open.file = NULL;
/* Has the filesystem initialised the file for us? */
if (filp->f_path.dentry == NULL) {
struct inode *inode = nd->path.dentry->d_inode;
if (inode->i_op->open) {
int flags = filp->f_flags;
put_filp(filp);
filp = inode->i_op->open(nd->path.dentry, flags, cred);
} else {
filp = __dentry_open(&nd->path, filp, NULL, cred);
}
}
return filp;
}
/*
* dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
* error.
*/
struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
const struct cred *cred)
{
struct path path = { .dentry = dentry, .mnt = mnt };
struct file *ret;
/* We must always pass in a valid mount pointer. */
BUG_ON(!mnt);
ret = vfs_open(&path, flags, cred);
path_put(&path);
return ret;
}
EXPORT_SYMBOL(dentry_open);
/**
* vfs_open - open the file at the given path
* @path: path to open
* @flags: open flags
* @cred: credentials to use
*
* Open the file. If successful, the returned file will have acquired
* an additional reference for path.
*/
struct file *vfs_open(struct path *path, int flags, const struct cred *cred)
{
struct file *f;
struct inode *inode = path->dentry->d_inode;
validate_creds(cred);
if (inode->i_op->open)
return inode->i_op->open(path->dentry, flags, cred);
f = get_empty_filp();
if (f == NULL)
return ERR_PTR(-ENFILE);
f->f_flags = flags;
return __dentry_open(path, f, NULL, cred);
}
EXPORT_SYMBOL(vfs_open);
static void __put_unused_fd(struct files_struct *files, unsigned int fd)
{
struct fdtable *fdt = files_fdtable(files);
__FD_CLR(fd, fdt->open_fds);
if (fd < files->next_fd)
files->next_fd = fd;
}
void put_unused_fd(unsigned int fd)
{
struct files_struct *files = current->files;
spin_lock(&files->file_lock);
__put_unused_fd(files, fd);
spin_unlock(&files->file_lock);
}
EXPORT_SYMBOL(put_unused_fd);
/*
* Install a file pointer in the fd array.
*
* The VFS is full of places where we drop the files lock between
* setting the open_fds bitmap and installing the file in the file
* array. At any such point, we are vulnerable to a dup2() race
* installing a file in the array before us. We need to detect this and
* fput() the struct file we are about to overwrite in this case.
*
* It should never happen - if we allow dup2() do it, _really_ bad things
* will follow.
*/
void fd_install(unsigned int fd, struct file *file)
{
struct files_struct *files = current->files;
struct fdtable *fdt;
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
BUG_ON(fdt->fd[fd] != NULL);
rcu_assign_pointer(fdt->fd[fd], file);
spin_unlock(&files->file_lock);
}
EXPORT_SYMBOL(fd_install);
static inline int build_open_flags(int flags, int mode, struct open_flags *op)
{
int lookup_flags = 0;
int acc_mode;
if (!(flags & O_CREAT))
mode = 0;
op->mode = mode;
/* Must never be set by userspace */
flags &= ~FMODE_NONOTIFY;
/*
* O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
* check for O_DSYNC if the need any syncing at all we enforce it's
* always set instead of having to deal with possibly weird behaviour
* for malicious applications setting only __O_SYNC.
*/
if (flags & __O_SYNC)
flags |= O_DSYNC;
/*
* If we have O_PATH in the open flag. Then we
* cannot have anything other than the below set of flags
*/
if (flags & O_PATH) {
flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
acc_mode = 0;
} else {
acc_mode = MAY_OPEN | ACC_MODE(flags);
}
op->open_flag = flags;
/* O_TRUNC implies we need access checks for write permissions */
if (flags & O_TRUNC)
acc_mode |= MAY_WRITE;
/* Allow the LSM permission hook to distinguish append
access from general write access. */
if (flags & O_APPEND)
acc_mode |= MAY_APPEND;
op->acc_mode = acc_mode;
op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
if (flags & O_CREAT) {
op->intent |= LOOKUP_CREATE;
if (flags & O_EXCL)
op->intent |= LOOKUP_EXCL;
}
if (flags & O_DIRECTORY)
lookup_flags |= LOOKUP_DIRECTORY;
if (!(flags & O_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
return lookup_flags;
}
static int exa_select(struct exa_select *sel)
{
int i;
int one=0;
int ret = -EFAULT;
/* first phase register on each queue */
for (i = 0; i < __FD_SETSIZE; i++)
{
__FD_CLR(i, &sel->result);
if (__FD_ISSET(i, &sel->select))
{
sel->elt[i].socket = exa_getsock(i);
if (sel->elt[i].socket == NULL)
{
ret = -EINVAL;
continue;
}
set_callbacks(sel->elt[i].socket, &sel->elt[i]);
if (sel->operation == EXA_SELECT_IN)
{
if (sock_readable(sel->elt[i].socket) == 1)
one = 1;
}
if (sel->operation == EXA_SELECT_OUT)
if (sock_writable(sel->elt[i].socket) == 1)
one = 1;
}
}
/* second phase : check if nothing arrived and wait if nothing arrived */
if (one==0)
{
int timeout = SELECT_TIMEOUT ;
set_current_state(TASK_INTERRUPTIBLE);
for (i = 0; i < __FD_SETSIZE; i++)
{
if (__FD_ISSET(i, &sel->select) && (sel->elt[i].socket != NULL))
{
if (sel->operation == EXA_SELECT_IN)
{
if (sock_readable(sel->elt[i].socket) == 1)
one = 1;
}
if (sel->operation == EXA_SELECT_OUT)
{
if (sock_writable(sel->elt[i].socket) == 1)
one = 1;
}
}
}
if (one == 0) /* if some data already pending, we must not wait (or some race can occur)*/
timeout = schedule_timeout(timeout);
set_current_state(TASK_RUNNING);
}
/* third : find wich socket receive/sent something */
for (i = __FD_SETSIZE - 1; i >= 0; i--)
{
if (__FD_ISSET(i, &sel->select))
{
if (sel->elt[i].socket == NULL)
continue;
if (sel->operation == EXA_SELECT_IN)
{
if (sock_readable(sel->elt[i].socket) == 1)
__FD_SET(i, &sel->result);
}
if (sel->operation == EXA_SELECT_OUT)
{
if (sock_writable(sel->elt[i].socket) == 1)
__FD_SET(i, &sel->result);
}
if ((__FD_ISSET(i, &sel->result)) && (ret == -EFAULT))
ret = 0;
restore_callbacks(sel->elt[i].socket, &sel->elt[i]);
fput(sel->elt[i].socket->file);
sel->elt[i].socket = NULL;
}
}
/* XXX this is not an error, -EFAULT is used here as the timeout return
* value....
* FIXME use ETIME to have an explicit timeout. */
if (ret == -EFAULT)
__FD_ZERO(&sel->result);
return ret;
}
