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; }