static ssize_t sdcardfskk_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
int err = 0;
struct file *lower_file;
struct dentry *dentry = file->f_path.dentry;
/* check disk space */
if (!check_min_free_space(dentry, count, 0)) {
printk(KERN_INFO "No minimum free space.\n");
return -ENOSPC;
}
lower_file = sdcardfskk_lower_file(file);
err = vfs_write(lower_file, buf, count, ppos);
/* update our inode times+sizes upon a successful lower write */
if (err >= 0) {
fsstack_copy_inode_size(dentry->d_inode,
lower_file->f_path.dentry->d_inode);
fsstack_copy_attr_times(dentry->d_inode,
lower_file->f_path.dentry->d_inode);
}
return err;
}
static ssize_t sdcardfskk_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
int err;
struct file *lower_file;
struct dentry *dentry = file->f_path.dentry;
#ifdef CONFIG_SDCARD_FS_FADV_NOACTIVE
struct backing_dev_info *bdi;
#endif
lower_file = sdcardfskk_lower_file(file);
#ifdef CONFIG_SDCARD_FS_FADV_NOACTIVE
if (file->f_mode & FMODE_NOACTIVE) {
if (!(lower_file->f_mode & FMODE_NOACTIVE)) {
bdi = lower_file->f_mapping->backing_dev_info;
lower_file->f_ra.ra_pages = bdi->ra_pages * 2;
spin_lock(&lower_file->f_lock);
lower_file->f_mode |= FMODE_NOACTIVE;
spin_unlock(&lower_file->f_lock);
}
}
#endif
err = vfs_read(lower_file, buf, count, ppos);
/* update our inode atime upon a successful lower read */
if (err >= 0)
fsstack_copy_attr_atime(dentry->d_inode,
lower_file->f_path.dentry->d_inode);
return err;
}
static int sdcardfskk_fasync(int fd, struct file *file, int flag)
{
int err = 0;
struct file *lower_file = NULL;
lower_file = sdcardfskk_lower_file(file);
if (lower_file->f_op && lower_file->f_op->fasync)
err = lower_file->f_op->fasync(fd, lower_file, flag);
return err;
}
static int sdcardfskk_flush(struct file *file, fl_owner_t id)
{
int err = 0;
struct file *lower_file = NULL;
lower_file = sdcardfskk_lower_file(file);
if (lower_file && lower_file->f_op && lower_file->f_op->flush)
err = lower_file->f_op->flush(lower_file, id);
return err;
}
/* release all lower object references & free the file info structure */
static int sdcardfskk_file_release(struct inode *inode, struct file *file)
{
struct file *lower_file;
lower_file = sdcardfskk_lower_file(file);
if (lower_file) {
sdcardfskk_set_lower_file(file, NULL);
fput(lower_file);
}
kfree(SDCARDFSKK_F(file));
return 0;
}
static int
sdcardfskk_fsync(struct file *file, int datasync)
{
int err;
struct file *lower_file;
struct path lower_path;
struct dentry *dentry = file->f_path.dentry;
lower_file = sdcardfskk_lower_file(file);
sdcardfskk_get_lower_path(dentry, &lower_path);
err = vfs_fsync(lower_file, datasync);
sdcardfskk_put_lower_path(dentry, &lower_path);
return err;
}
static int sdcardfskk_readdir(struct file *file, void *dirent, filldir_t filldir)
{
int err = 0;
struct file *lower_file = NULL;
struct dentry *dentry = file->f_path.dentry;
lower_file = sdcardfskk_lower_file(file);
lower_file->f_pos = file->f_pos;
err = vfs_readdir(lower_file, filldir, dirent);
file->f_pos = lower_file->f_pos;
if (err >= 0) /* copy the atime */
fsstack_copy_attr_atime(dentry->d_inode,
lower_file->f_path.dentry->d_inode);
return err;
}
static long sdcardfskk_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
long err = -ENOTTY;
struct file *lower_file;
lower_file = sdcardfskk_lower_file(file);
/* XXX: use vfs_ioctl if/when VFS exports it */
if (!lower_file || !lower_file->f_op)
goto out;
if (lower_file->f_op->compat_ioctl)
err = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
out:
return err;
}
static int sdcardfskk_open(struct inode *inode, struct file *file)
{
int err = 0;
struct file *lower_file = NULL;
struct path lower_path;
struct dentry *dentry = file->f_path.dentry;
struct dentry *parent = dget_parent(dentry);
struct sdcardfskk_sb_info *sbi = SDCARDFSKK_SB(dentry->d_sb);
const struct cred *saved_cred = NULL;
int has_rw;
/* don't open unhashed/deleted files */
if (d_unhashed(dentry)) {
err = -ENOENT;
goto out_err;
}
has_rw = get_caller_has_rw_locked_kitkat(sbi->pkgl_id, sbi->options.derive);
if(!check_caller_access_to_name_kitkat(parent->d_inode, dentry->d_name.name,
sbi->options.derive,
open_flags_to_access_mode_kitkat(file->f_flags), has_rw)) {
printk(KERN_INFO "%s: need to check the caller's gid in packages.list\n"
" dentry: %s, task:%s\n",
__func__, dentry->d_name.name, current->comm);
err = -EACCES;
goto out_err;
}
/* save current_cred and override it */
OVERRIDE_CRED(sbi, saved_cred);
file->private_data =
kzalloc(sizeof(struct sdcardfskk_file_info), GFP_KERNEL);
if (!SDCARDFSKK_F(file)) {
err = -ENOMEM;
goto out_revert_cred;
}
/* open lower object and link sdcardfskk's file struct to lower's */
sdcardfskk_get_lower_path(file->f_path.dentry, &lower_path);
lower_file = dentry_open(lower_path.dentry, lower_path.mnt,
file->f_flags, current_cred());
if (IS_ERR(lower_file)) {
err = PTR_ERR(lower_file);
lower_file = sdcardfskk_lower_file(file);
if (lower_file) {
sdcardfskk_set_lower_file(file, NULL);
fput(lower_file); /* fput calls dput for lower_dentry */
}
} else {
sdcardfskk_set_lower_file(file, lower_file);
}
if (err)
kfree(SDCARDFSKK_F(file));
else {
mutex_lock(&inode->i_mutex);
sdcardfskk_copy_inode_attr(inode, sdcardfskk_lower_inode(inode));
fix_derived_permission(inode);
mutex_unlock(&inode->i_mutex);
}
out_revert_cred:
REVERT_CRED(saved_cred);
out_err:
dput(parent);
return err;
}
static int sdcardfskk_mmap(struct file *file, struct vm_area_struct *vma)
{
int err = 0;
bool willwrite;
struct file *lower_file;
const struct vm_operations_struct *saved_vm_ops = NULL;
/* this might be deferred to mmap's writepage */
willwrite = ((vma->vm_flags | VM_SHARED | VM_WRITE) == vma->vm_flags);
/*
* File systems which do not implement ->writepage may use
* generic_file_readonly_mmap as their ->mmap op. If you call
* generic_file_readonly_mmap with VM_WRITE, you'd get an -EINVAL.
* But we cannot call the lower ->mmap op, so we can't tell that
* writeable mappings won't work. Therefore, our only choice is to
* check if the lower file system supports the ->writepage, and if
* not, return EINVAL (the same error that
* generic_file_readonly_mmap returns in that case).
*/
lower_file = sdcardfskk_lower_file(file);
if (willwrite && !lower_file->f_mapping->a_ops->writepage) {
err = -EINVAL;
printk(KERN_ERR "sdcardfskk: lower file system does not "
"support writeable mmap\n");
goto out;
}
/*
* find and save lower vm_ops.
*
* XXX: the VFS should have a cleaner way of finding the lower vm_ops
*/
if (!SDCARDFSKK_F(file)->lower_vm_ops) {
err = lower_file->f_op->mmap(lower_file, vma);
if (err) {
printk(KERN_ERR "sdcardfskk: lower mmap failed %d\n", err);
goto out;
}
saved_vm_ops = vma->vm_ops; /* save: came from lower ->mmap */
err = do_munmap(current->mm, vma->vm_start,
vma->vm_end - vma->vm_start);
if (err) {
printk(KERN_ERR "sdcardfskk: do_munmap failed %d\n", err);
goto out;
}
}
/*
* Next 3 lines are all I need from generic_file_mmap. I definitely
* don't want its test for ->readpage which returns -ENOEXEC.
*/
file_accessed(file);
vma->vm_ops = &sdcardfskk_vm_ops;
vma->vm_flags |= VM_CAN_NONLINEAR;
file->f_mapping->a_ops = &sdcardfskk_aops; /* set our aops */
if (!SDCARDFSKK_F(file)->lower_vm_ops) /* save for our ->fault */
SDCARDFSKK_F(file)->lower_vm_ops = saved_vm_ops;
out:
return err;
}
static int sdcardfskk_setattr(struct dentry *dentry, struct iattr *ia)
{
int err = 0;
struct dentry *lower_dentry;
struct inode *inode;
struct inode *lower_inode;
struct path lower_path;
struct iattr lower_ia;
struct sdcardfskk_sb_info *sbi = SDCARDFSKK_SB(dentry->d_sb);
struct dentry *parent;
int has_rw;
inode = dentry->d_inode;
/*
* Check if user has permission to change inode. We don't check if
* this user can change the lower inode: that should happen when
* calling notify_change on the lower inode.
*/
err = inode_change_ok(inode, ia);
/* no vfs_XXX operations required, cred overriding will be skipped. wj*/
if (!err) {
/* check the Android group ID */
has_rw = get_caller_has_rw_locked(sbi->pkgl_id, sbi->options.derive);
parent = dget_parent(dentry);
if(!check_caller_access_to_name(parent->d_inode, dentry->d_name.name,
sbi->options.derive, 1, has_rw)) {
printk(KERN_INFO "%s: need to check the caller's gid in packages.list\n"
" dentry: %s, task:%s\n",
__func__, dentry->d_name.name, current->comm);
err = -EACCES;
}
dput(parent);
}
if (err)
goto out_err;
sdcardfskk_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_inode = sdcardfskk_lower_inode(inode);
/* prepare our own lower struct iattr (with the lower file) */
memcpy(&lower_ia, ia, sizeof(lower_ia));
if (ia->ia_valid & ATTR_FILE)
lower_ia.ia_file = sdcardfskk_lower_file(ia->ia_file);
lower_ia.ia_valid &= ~(ATTR_UID | ATTR_GID | ATTR_MODE);
/*
* If shrinking, first truncate upper level to cancel writing dirty
* pages beyond the new eof; and also if its' maxbytes is more
* limiting (fail with -EFBIG before making any change to the lower
* level). There is no need to vmtruncate the upper level
* afterwards in the other cases: we fsstack_copy_inode_size from
* the lower level.
*/
if (current->mm)
down_write(¤t->mm->mmap_sem);
if (ia->ia_valid & ATTR_SIZE) {
err = inode_newsize_ok(inode, ia->ia_size);
if (err) {
if (current->mm)
up_write(¤t->mm->mmap_sem);
goto out;
}
truncate_setsize(inode, ia->ia_size);
}
/*
* mode change is for clearing setuid/setgid bits. Allow lower fs
* to interpret this in its own way.
*/
if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
lower_ia.ia_valid &= ~ATTR_MODE;
/* notify the (possibly copied-up) lower inode */
/*
* Note: we use lower_dentry->d_inode, because lower_inode may be
* unlinked (no inode->i_sb and i_ino==0. This happens if someone
* tries to open(), unlink(), then ftruncate() a file.
*/
mutex_lock(&lower_dentry->d_inode->i_mutex);
err = notify_change(lower_dentry, &lower_ia); /* note: lower_ia */
mutex_unlock(&lower_dentry->d_inode->i_mutex);
if (current->mm)
up_write(¤t->mm->mmap_sem);
if (err)
goto out;
/* get attributes from the lower inode */
fsstack_copy_attr_all(inode, lower_inode);
/* update derived permission of the upper inode */
fix_derived_permission(inode);
/*
* Not running fsstack_copy_inode_size(inode, lower_inode), because
* VFS should update our inode size, and notify_change on
* lower_inode should update its size.
*/
out:
sdcardfskk_put_lower_path(dentry, &lower_path);
out_err:
return err;
}
