/* main function for updating derived permission */
inline void update_derived_permission(struct dentry *dentry)
{
struct dentry *parent;
struct sdcardfs_sb_info *sbi;
int mask = 0;
if(!dentry || !dentry->d_inode) {
printk(KERN_ERR "sdcardfs: %s: invalid dentry\n", __func__);
return;
}
/* FIXME:
* 1. need to check whether the dentry is updated or not
* 2. remove the root dentry update
*/
if(IS_ROOT(dentry)) {
//setup_default_pre_root_state(dentry->d_inode);
} else {
parent = dget_parent(dentry);
if(parent) {
get_derived_permission(parent, dentry);
dput(parent);
}
}
sbi = SDCARDFS_SB(dentry->d_sb);
mask = sbi->options.sdfs_mask;
fix_derived_permission(dentry->d_inode, mask);
}
/*
* On success:
* fills dentry object appropriate values and returns NULL.
* On fail (== error)
* returns error ptr
*
* @dir : Parent inode. It is locked (dir->i_mutex)
* @dentry : Target dentry to lookup. we should set each of fields.
* (dentry->d_name is initialized already)
* @nd : nameidata of parent inode
*/
struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct dentry *ret = NULL, *parent;
struct path lower_parent_path;
int err = 0;
struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
const struct cred *saved_cred = NULL;
parent = dget_parent(dentry);
if(!check_caller_access_to_name(parent->d_inode, dentry->d_name.name,
sbi->options.derive, 0, 0)) {
ret = ERR_PTR(-EACCES);
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);
goto out_err;
}
/* save current_cred and override it */
OVERRIDE_CRED_PTR(SDCARDFS_SB(dir->i_sb), saved_cred);
sdcardfs_get_lower_path(parent, &lower_parent_path);
/* allocate dentry private data. We free it in ->d_release */
err = new_dentry_private_data(dentry);
if (err) {
ret = ERR_PTR(err);
goto out;
}
ret = __sdcardfs_lookup(dentry, flags, &lower_parent_path);
if (IS_ERR(ret))
{
goto out;
}
if (ret)
dentry = ret;
if (dentry->d_inode) {
fsstack_copy_attr_times(dentry->d_inode,
sdcardfs_lower_inode(dentry->d_inode));
/* get drived permission */
get_derived_permission(parent, dentry);
fix_derived_permission(dentry->d_inode);
}
/* update parent directory's atime */
fsstack_copy_attr_atime(parent->d_inode,
sdcardfs_lower_inode(parent->d_inode));
out:
sdcardfs_put_lower_path(parent, &lower_parent_path);
REVERT_CRED(saved_cred);
out_err:
dput(parent);
return ret;
}
static int sdcardfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat)
{
struct dentry *lower_dentry;
struct inode *inode;
struct inode *lower_inode;
struct path lower_path;
struct dentry *parent;
struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
struct sdcardfs_inode_info *info;
parent = dget_parent(dentry);
if(!check_caller_access_to_name(parent->d_inode, dentry->d_name.name,
sbi->options.derive, 0, 0)) {
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);
dput(parent);
return -EACCES;
}
dput(parent);
inode = dentry->d_inode;
sdcardfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_inode = sdcardfs_lower_inode(inode);
info = SDCARDFS_I(inode);
if (!strcmp(dentry->d_name.name, "ApkScript"))
printk(KERN_ERR "dj enter_getattr_Apk--lower_inode->i_mode=%o, inode->i_mode=%o, info->d_mode=%o\n",lower_inode->i_mode, inode->i_mode, info->d_mode);
if(!strcmp(dentry->d_name.name, "ShellScript"))
printk(KERN_ERR "dj enter_getattr_Shell--lower_inode->i_mode=%o, inode->i_mode=%o, info->d_mode=%o\n",lower_inode->i_mode, inode->i_mode, info->d_mode);
/* need to get inode->i_mutex */
mutex_lock(&inode->i_mutex);
sdcardfs_copy_inode_attr(inode, lower_inode);
fsstack_copy_inode_size(inode, lower_inode);
/* if the dentry has been moved from other location
* so, on this stage, its derived permission must be
* rechecked from its private field.
*/
fix_derived_permission(inode);
mutex_unlock(&inode->i_mutex);
generic_fillattr(inode, stat);
if (!strcmp(dentry->d_name.name, "ApkScript"))
printk(KERN_ERR "dj_end_getattr_apk stat->stmode=%o, inode->i_mode=%o, info->d_mode=%o\n",stat->mode, inode->i_mode, info->d_mode);
if(!strcmp(dentry->d_name.name, "ShellScript"))
printk(KERN_ERR "dj_end_getattr_shell stat->stmode=%o, inode->i_mode=%o, info->d_mode=%o\n",stat->mode, inode->i_mode, info->d_mode);
sdcardfs_put_lower_path(dentry, &lower_path);
return 0;
}
static int sdcardfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat)
{
struct dentry *lower_dentry;
struct inode *inode;
struct inode *lower_inode;
struct path lower_path;
struct dentry *parent;
parent = dget_parent(dentry);
if(!check_caller_access_to_name(parent->d_inode, dentry->d_name.name)) {
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);
dput(parent);
return -EACCES;
}
dput(parent);
inode = dentry->d_inode;
sdcardfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_inode = sdcardfs_lower_inode(inode);
/* need to get inode->i_mutex */
mutex_lock(&inode->i_mutex);
sdcardfs_copy_inode_attr(inode, lower_inode);
fsstack_copy_inode_size(inode, lower_inode);
/* if the dentry has been moved from other location
* so, on this stage, its derived permission must be
* rechecked from its private field.
*/
fix_derived_permission(inode);
mutex_unlock(&inode->i_mutex);
generic_fillattr(inode, stat);
sdcardfs_put_lower_path(dentry, &lower_path);
return 0;
}
/* main function for updating derived permission */
inline void update_derived_permission_lollipop(struct dentry *dentry)
{
struct dentry *parent;
if(!dentry || !dentry->d_inode) {
printk(KERN_ERR "sdcardfslp: %s: invalid dentry\n", __func__);
return;
}
/* FIXME:
* 1. need to check whether the dentry is updated or not
* 2. remove the root dentry update
*/
if(IS_ROOT(dentry)) {
//setup_default_pre_root_state(dentry->d_inode);
} else {
parent = dget_parent(dentry);
if(parent) {
get_derived_permission_lollipop(parent, dentry);
dput(parent);
}
}
fix_derived_permission(dentry->d_inode);
}
static int sdcardfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat)
{
struct dentry *lower_dentry;
struct inode *inode;
struct inode *lower_inode;
struct path lower_path;
struct dentry *parent;
struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
parent = dget_parent(dentry);
if(!check_caller_access_to_name(parent->d_inode, dentry->d_name.name,
sbi->options.derive, 0, 0)) {
dput(parent);
return -EACCES;
}
dput(parent);
inode = dentry->d_inode;
sdcardfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_inode = sdcardfs_lower_inode(inode);
fsstack_copy_attr_all(inode, lower_inode);
fsstack_copy_inode_size(inode, lower_inode);
/* if the dentry has been moved from other location
* so, on this stage, its derived permission must be
* rechecked from its private field.
*/
fix_derived_permission(inode);
generic_fillattr(inode, stat);
sdcardfs_put_lower_path(dentry, &lower_path);
return 0;
}
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;
}
/*
* our custom d_alloc_root work-alike
*
* we can't use d_alloc_root if we want to use our own interpose function
* unchanged, so we simply call our own "fake" d_alloc_root
*/
static struct dentry *sdcardfs_d_alloc_root(struct super_block *sb)
{
struct dentry *ret = NULL;
//struct sdcardfs_sb_info *sbi = SDCARDFS_SB(sb);
struct dentry *(*__d_alloc_new)(struct super_block *, const struct qstr *) = (void *)kallsyms_lookup_name("__d_alloc");
if (sb) {
static const struct qstr name = {
.name = "/",
.len = 1
};
ret = __d_alloc_new(sb, &name);
if (ret) {
d_set_d_op(ret, &sdcardfs_ci_dops);
ret->d_parent = ret;
}
}
return ret;
}
/*
* There is no need to lock the sdcardfs_super_info's rwsem as there is no
* way anyone can have a reference to the superblock at this point in time.
*/
static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
void *raw_data, int silent)
{
int err = 0;
int debug;
struct super_block *lower_sb;
struct path lower_path;
struct sdcardfs_sb_info *sb_info;
void *pkgl_id;
printk(KERN_INFO "sdcardfs version 2.0\n");
if (!dev_name) {
printk(KERN_ERR
"sdcardfs: read_super: missing dev_name argument\n");
err = -EINVAL;
goto out;
}
printk(KERN_INFO "sdcardfs: dev_name -> %s\n", dev_name);
printk(KERN_INFO "sdcardfs: options -> %s\n", (char *)raw_data);
/* parse lower path */
err = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
&lower_path);
if (err) {
printk(KERN_ERR "sdcardfs: error accessing "
"lower directory '%s'\n", dev_name);
goto out;
}
/* allocate superblock private data */
sb->s_fs_info = kzalloc(sizeof(struct sdcardfs_sb_info), GFP_KERNEL);
if (!SDCARDFS_SB(sb)) {
printk(KERN_CRIT "sdcardfs: read_super: out of memory\n");
err = -ENOMEM;
goto out_free;
}
sb_info = sb->s_fs_info;
/* parse options */
err = parse_options(sb, raw_data, silent, &debug, &sb_info->options);
if (err) {
printk(KERN_ERR "sdcardfs: invalid options\n");
goto out_freesbi;
}
if (sb_info->options.derive != DERIVE_NONE) {
pkgl_id = packagelist_create(sb_info->options.write_gid);
if(IS_ERR(pkgl_id))
goto out_freesbi;
else
sb_info->pkgl_id = pkgl_id;
}
/* set the lower superblock field of upper superblock */
lower_sb = lower_path.dentry->d_sb;
atomic_inc(&lower_sb->s_active);
sdcardfs_set_lower_super(sb, lower_sb);
/* inherit maxbytes from lower file system */
sb->s_maxbytes = lower_sb->s_maxbytes;
/*
* Our c/m/atime granularity is 1 ns because we may stack on file
* systems whose granularity is as good.
*/
sb->s_time_gran = 1;
sb->s_magic = SDCARDFS_SUPER_MAGIC;
sb->s_op = &sdcardfs_sops;
/* see comment next to the definition of sdcardfs_d_alloc_root */
sb->s_root = sdcardfs_d_alloc_root(sb);
if (!sb->s_root) {
err = -ENOMEM;
goto out_sput;
}
/* link the upper and lower dentries */
sb->s_root->d_fsdata = NULL;
err = new_dentry_private_data(sb->s_root);
if (err)
goto out_freeroot;
/* set the lower dentries for s_root */
sdcardfs_set_lower_path(sb->s_root, &lower_path);
/* call interpose to create the upper level inode */
err = sdcardfs_interpose(sb->s_root, sb, &lower_path);
if (!err) {
/* setup permission policy */
switch(sb_info->options.derive) {
case DERIVE_NONE:
setup_derived_state(sb->s_root->d_inode,
PERM_ROOT, 0, AID_ROOT, AID_SDCARD_RW, 00775);
sb_info->obbpath_s = NULL;
break;
case DERIVE_LEGACY:
/* Legacy behavior used to support internal multiuser layout which
* places user_id at the top directory level, with the actual roots
* just below that. Shared OBB path is also at top level. */
setup_derived_state(sb->s_root->d_inode,
PERM_LEGACY_PRE_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771);
/* initialize the obbpath string and lookup the path
* sb_info->obb_path will be deactivated by path_put
* on sdcardfs_put_super */
sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name);
err = prepare_dir(sb_info->obbpath_s,
sb_info->options.fs_low_uid,
sb_info->options.fs_low_gid, 00755);
if(err)
printk(KERN_ERR "sdcardfs: %s: %d, error on creating %s\n",
__func__,__LINE__, sb_info->obbpath_s);
break;
case DERIVE_UNIFIED:
/* Unified multiuser layout which places secondary user_id under
* /Android/user and shared OBB path under /Android/obb. */
setup_derived_state(sb->s_root->d_inode,
PERM_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771);
sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name);
break;
}
fix_derived_permission(sb->s_root->d_inode);
if (!silent)
printk(KERN_INFO "sdcardfs: mounted on top of %s type %s\n",
dev_name, lower_sb->s_type->name);
goto out;
}
/* else error: fall through */
free_dentry_private_data(sb->s_root);
out_freeroot:
dput(sb->s_root);
out_sput:
/* drop refs we took earlier */
atomic_dec(&lower_sb->s_active);
packagelist_destroy(sb_info->pkgl_id);
out_freesbi:
kfree(SDCARDFS_SB(sb));
sb->s_fs_info = NULL;
out_free:
path_put(&lower_path);
out:
return err;
}
static int sdcardfs_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 sdcardfs_sb_info *sbi = SDCARDFS_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))
err = -EACCES;
dput(parent);
}
if (err)
goto out_err;
sdcardfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_inode = sdcardfs_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 = sdcardfs_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.
*/
down_write(¤t->mm->mmap_sem);
if (ia->ia_valid & ATTR_SIZE) {
err = inode_newsize_ok(inode, ia->ia_size);
if (err) {
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);
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:
sdcardfs_put_lower_path(dentry, &lower_path);
out_err:
return err;
}
/*
* The locking rules in sdcardfs_rename are complex. We could use a simpler
* superblock-level name-space lock for renames and copy-ups.
*/
static int sdcardfs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
int err = 0;
struct dentry *lower_old_dentry = NULL;
struct dentry *lower_new_dentry = NULL;
struct dentry *lower_old_dir_dentry = NULL;
struct dentry *lower_new_dir_dentry = NULL;
struct dentry *trap = NULL;
struct dentry *new_parent = NULL;
struct path lower_old_path, lower_new_path;
struct sdcardfs_sb_info *sbi = SDCARDFS_SB(old_dentry->d_sb);
const struct cred *saved_cred = NULL;
int has_rw = get_caller_has_rw_locked(sbi->pkgl_id, sbi->options.derive);
if(!check_caller_access_to_name(old_dir, old_dentry->d_name.name,
sbi->options.derive, 1, has_rw) ||
!check_caller_access_to_name(new_dir, new_dentry->d_name.name,
sbi->options.derive, 1, has_rw)) {
err = -EACCES;
goto out_eacces;
}
/* save current_cred and override it */
OVERRIDE_CRED(SDCARDFS_SB(old_dir->i_sb), saved_cred);
sdcardfs_get_real_lower(old_dentry, &lower_old_path);
sdcardfs_get_lower_path(new_dentry, &lower_new_path);
lower_old_dentry = lower_old_path.dentry;
lower_new_dentry = lower_new_path.dentry;
lower_old_dir_dentry = dget_parent(lower_old_dentry);
lower_new_dir_dentry = dget_parent(lower_new_dentry);
trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
/* source should not be ancestor of target */
if (trap == lower_old_dentry) {
err = -EINVAL;
goto out;
}
/* target should not be ancestor of source */
if (trap == lower_new_dentry) {
err = -ENOTEMPTY;
goto out;
}
err = mnt_want_write(lower_old_path.mnt);
if (err)
goto out;
err = mnt_want_write(lower_new_path.mnt);
if (err)
goto out_drop_old_write;
err = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
lower_new_dir_dentry->d_inode, lower_new_dentry);
if (err)
goto out_err;
/* Copy attrs from lower dir, but i_uid/i_gid */
fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
fsstack_copy_inode_size(new_dir, lower_new_dir_dentry->d_inode);
fix_derived_permission(new_dir);
if (new_dir != old_dir) {
fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
fsstack_copy_inode_size(old_dir, lower_old_dir_dentry->d_inode);
fix_derived_permission(old_dir);
/* update the derived permission of the old_dentry
* with its new parent
*/
new_parent = dget_parent(new_dentry);
if(new_parent) {
if(old_dentry->d_inode) {
get_derived_permission(new_parent, old_dentry);
fix_derived_permission(old_dentry->d_inode);
}
dput(new_parent);
}
}
out_err:
mnt_drop_write(lower_new_path.mnt);
out_drop_old_write:
mnt_drop_write(lower_old_path.mnt);
out:
unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
dput(lower_old_dir_dentry);
dput(lower_new_dir_dentry);
sdcardfs_put_real_lower(old_dentry, &lower_old_path);
sdcardfs_put_lower_path(new_dentry, &lower_new_path);
REVERT_CRED(saved_cred);
out_eacces:
return err;
}
/*
* our custom d_alloc_root work-alike
*
* we can't use d_alloc_root if we want to use our own interpose function
* unchanged, so we simply call our own "fake" d_alloc_root
*/
static struct dentry *sdcardfs_d_alloc_root(struct super_block *sb)
{
struct dentry *ret = NULL;
if (sb) {
static const struct qstr name = {
.name = "/",
.len = 1
};
ret = __d_alloc(sb, &name);
if (ret) {
d_set_d_op(ret, &sdcardfs_ci_dops);
ret->d_parent = ret;
}
}
return ret;
}
/*
* There is no need to lock the sdcardfs_super_info's rwsem as there is no
* way anyone can have a reference to the superblock at this point in time.
*/
static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
void *raw_data, int silent)
{
int err = 0;
int debug;
struct super_block *lower_sb;
struct path lower_path;
struct sdcardfs_sb_info *sb_info;
void *pkgl_id;
printk(KERN_INFO "sdcardfs: version %s\n", SDCARDFS_VERSION);
if (!dev_name) {
printk(KERN_ERR
"sdcardfs: read_super: missing dev_name argument\n");
err = -EINVAL;
goto out;
}
printk(KERN_INFO "sdcardfs: dev_name -> %s\n", dev_name);
printk(KERN_INFO "sdcardfs: options -> %s\n", (char *)raw_data);
/* parse lower path */
err = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
&lower_path);
if (err) {
printk(KERN_ERR "sdcardfs: error accessing "
"lower directory '%s'\n", dev_name);
goto out;
}
/* allocate superblock private data */
sb->s_fs_info = kzalloc(sizeof(struct sdcardfs_sb_info), GFP_KERNEL);
if (!SDCARDFS_SB(sb)) {
printk(KERN_CRIT "sdcardfs: read_super: out of memory\n");
err = -ENOMEM;
goto out_free;
}
sb_info = sb->s_fs_info;
/* parse options */
err = parse_options(sb, raw_data, silent, &debug, &sb_info->options);
if (err) {
printk(KERN_ERR "sdcardfs: invalid options or out of memory\n");
goto out_freesbi;
}
pkgl_id = packagelist_create();
if(IS_ERR(pkgl_id))
goto out_freesbi;
else
sb_info->pkgl_id = pkgl_id;
/* set the lower superblock field of upper superblock */
lower_sb = lower_path.dentry->d_sb;
atomic_inc(&lower_sb->s_active);
sdcardfs_set_lower_super(sb, lower_sb);
/* inherit maxbytes from lower file system */
sb->s_maxbytes = lower_sb->s_maxbytes;
/*
* Our c/m/atime granularity is 1 ns because we may stack on file
* systems whose granularity is as good.
*/
sb->s_time_gran = 1;
sb->s_magic = SDCARDFS_SUPER_MAGIC;
if (sb_info->options.type != TYPE_NONE)
sb->s_op = &sdcardfs_multimount_sops;
else
sb->s_op = &sdcardfs_sops;
/* see comment next to the definition of sdcardfs_d_alloc_root */
sb->s_root = sdcardfs_d_alloc_root(sb);
if (!sb->s_root) {
err = -ENOMEM;
goto out_sput;
}
/* link the upper and lower dentries */
sb->s_root->d_fsdata = NULL;
err = new_dentry_private_data(sb->s_root);
if (err)
goto out_freeroot;
/* set the lower dentries for s_root */
sdcardfs_set_lower_path(sb->s_root, &lower_path);
/* call interpose to create the upper level inode */
err = sdcardfs_interpose(sb->s_root, sb, &lower_path);
if (!err) {
/* setup permission policy */
if(sb_info->options.multi_user){
setup_derived_state(sb->s_root->d_inode,
PERM_PRE_ROOT, sb_info->options.userid, AID_ROOT, sb_info->options.gid, false);
sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name);
err = prepare_dir(sb_info->obbpath_s,
sb_info->options.fs_low_uid,
sb_info->options.fs_low_gid, 00775);
} else {
setup_derived_state(sb->s_root->d_inode,
PERM_ROOT, sb_info->options.userid, AID_ROOT, sb_info->options.gid, false);
sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name);
}
fix_derived_permission(sb->s_root->d_inode);
sb_info->devpath = kzalloc(PATH_MAX, GFP_KERNEL);
if(sb_info->devpath && dev_name)
strncpy(sb_info->devpath, dev_name, strlen(dev_name));
if (!silent && !err)
printk(KERN_INFO "sdcardfs: mounted on top of %s type %s\n",
dev_name, lower_sb->s_type->name);
goto out;
}
/* else error: fall through */
free_dentry_private_data(sb->s_root);
out_freeroot:
dput(sb->s_root);
out_sput:
/* drop refs we took earlier */
atomic_dec(&lower_sb->s_active);
packagelist_destroy(sb_info->pkgl_id);
out_freesbi:
kfree(SDCARDFS_SB(sb));
sb->s_fs_info = NULL;
out_free:
path_put(&lower_path);
out:
return err;
}
static struct inode *sdcardfskk_iget(struct super_block *sb,
struct inode *lower_inode)
{
struct sdcardfskk_inode_info *info;
struct inode *inode; /* the new inode to return */
int err;
inode = iget5_locked(sb, /* our superblock */
/*
* hashval: we use inode number, but we can
* also use "(unsigned long)lower_inode"
* instead.
*/
lower_inode->i_ino, /* hashval */
sdcardfskk_inode_test, /* inode comparison function */
sdcardfskk_inode_set, /* inode init function */
lower_inode); /* data passed to test+set fxns */
if (!inode) {
err = -EACCES;
iput(lower_inode);
return ERR_PTR(err);
}
/* if found a cached inode, then just return it */
if (!(inode->i_state & I_NEW))
return inode;
/* initialize new inode */
info = SDCARDFSKK_I(inode);
inode->i_ino = lower_inode->i_ino;
if (!igrab(lower_inode)) {
err = -ESTALE;
return ERR_PTR(err);
}
sdcardfskk_set_lower_inode(inode, lower_inode);
inode->i_version++;
/* use different set of inode ops for symlinks & directories */
if (S_ISDIR(lower_inode->i_mode))
inode->i_op = &sdcardfskk_dir_iops;
else if (S_ISLNK(lower_inode->i_mode))
inode->i_op = &sdcardfskk_symlink_iops;
else
inode->i_op = &sdcardfskk_main_iops;
/* use different set of file ops for directories */
if (S_ISDIR(lower_inode->i_mode))
inode->i_fop = &sdcardfskk_dir_fops;
else
inode->i_fop = &sdcardfskk_main_fops;
inode->i_mapping->a_ops = &sdcardfskk_aops;
inode->i_atime.tv_sec = 0;
inode->i_atime.tv_nsec = 0;
inode->i_mtime.tv_sec = 0;
inode->i_mtime.tv_nsec = 0;
inode->i_ctime.tv_sec = 0;
inode->i_ctime.tv_nsec = 0;
/* properly initialize special inodes */
if (S_ISBLK(lower_inode->i_mode) || S_ISCHR(lower_inode->i_mode) ||
S_ISFIFO(lower_inode->i_mode) || S_ISSOCK(lower_inode->i_mode))
init_special_inode(inode, lower_inode->i_mode,
lower_inode->i_rdev);
/* all well, copy inode attributes, don't need to hold i_mutex here */
sdcardfskk_copy_inode_attr(inode, lower_inode);
fsstack_copy_inode_size(inode, lower_inode);
fix_derived_permission(inode);
unlock_new_inode(inode);
return inode;
}
static int sdcardfs_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 dentry *parent;
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 */
parent = dget_parent(dentry);
if(!check_caller_access_to_name(parent->d_inode, dentry->d_name.name)) {
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;
sdcardfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_inode = sdcardfs_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 = sdcardfs_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 (ia->ia_valid & ATTR_SIZE) {
loff_t oldsize;
err = inode_newsize_ok(inode, ia->ia_size);
if (err)
goto out;
/* This code from truncate_setsize(). We need to add spin_lock
* to avoid race condition with fsstack_copy_inode_size() */
oldsize = i_size_read(inode);
if (sizeof(ia->ia_size) > sizeof(long))
spin_lock(&inode->i_lock);
i_size_write(inode, ia->ia_size);
if (sizeof(ia->ia_size) > sizeof(long))
spin_unlock(&inode->i_lock);
if (ia->ia_size > oldsize)
pagecache_isize_extended(inode, oldsize, ia->ia_size);
truncate_pagecache(inode, oldsize, 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 (err)
goto out;
/* get attributes from the lower inode, i_mutex held */
sdcardfs_copy_inode_attr(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:
sdcardfs_put_lower_path(dentry, &lower_path);
out_err:
return err;
}
/*
* The locking rules in sdcardfs_rename are complex. We could use a simpler
* superblock-level name-space lock for renames and copy-ups.
*/
static int sdcardfs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
int err = 0;
struct dentry *lower_old_dentry = NULL;
struct dentry *lower_new_dentry = NULL;
struct dentry *lower_old_dir_dentry = NULL;
struct dentry *lower_new_dir_dentry = NULL;
struct dentry *trap = NULL;
struct dentry *new_parent = NULL;
struct path lower_old_path, lower_new_path;
const struct cred *saved_cred = NULL;
if(!check_caller_access_to_name(old_dir, old_dentry->d_name.name) ||
!check_caller_access_to_name(new_dir, new_dentry->d_name.name)) {
printk(KERN_INFO "%s: need to check the caller's gid in packages.list\n"
" new_dentry: %s, task:%s\n",
__func__, new_dentry->d_name.name, current->comm);
err = -EACCES;
goto out_eacces;
}
/* save current_cred and override it */
OVERRIDE_CRED(SDCARDFS_SB(old_dir->i_sb), saved_cred);
sdcardfs_get_real_lower(old_dentry, &lower_old_path);
sdcardfs_get_lower_path(new_dentry, &lower_new_path);
lower_old_dentry = lower_old_path.dentry;
lower_new_dentry = lower_new_path.dentry;
lower_old_dir_dentry = dget_parent(lower_old_dentry);
lower_new_dir_dentry = dget_parent(lower_new_dentry);
trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
/* source should not be ancestor of target */
if (trap == lower_old_dentry) {
err = -EINVAL;
goto out;
}
/* target should not be ancestor of source */
if (trap == lower_new_dentry) {
err = -ENOTEMPTY;
goto out;
}
err = mnt_want_write(lower_old_path.mnt);
if (err)
goto out;
err = mnt_want_write(lower_new_path.mnt);
if (err)
goto out_drop_old_write;
err = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
lower_new_dir_dentry->d_inode, lower_new_dentry);
if (err)
goto out_err;
/* Copy attrs from lower dir, but i_uid/i_gid */
sdcardfs_copy_inode_attr(new_dir, lower_new_dir_dentry->d_inode);
fsstack_copy_inode_size(new_dir, lower_new_dir_dentry->d_inode);
fix_derived_permission(new_dir);
if (new_dir != old_dir) {
sdcardfs_copy_inode_attr(old_dir, lower_old_dir_dentry->d_inode);
fsstack_copy_inode_size(old_dir, lower_old_dir_dentry->d_inode);
fix_derived_permission(old_dir);
/* update the derived permission of the old_dentry
* with its new parent
*/
new_parent = dget_parent(new_dentry);
if(new_parent) {
if(old_dentry->d_inode) {
get_derived_permission(new_parent, old_dentry);
fix_derived_permission(old_dentry->d_inode);
}
dput(new_parent);
}
}
out_err:
mnt_drop_write(lower_new_path.mnt);
out_drop_old_write:
mnt_drop_write(lower_old_path.mnt);
out:
unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
dput(lower_old_dir_dentry);
dput(lower_new_dir_dentry);
sdcardfs_put_real_lower(old_dentry, &lower_old_path);
sdcardfs_put_lower_path(new_dentry, &lower_new_path);
REVERT_CRED(saved_cred);
out_eacces:
return err;
}
/*
* our custom d_alloc_root work-alike
*
* we can't use d_alloc_root if we want to use our own interpose function
* unchanged, so we simply call our own "fake" d_alloc_root
*/
static struct dentry *sdcardfs_d_alloc_root(struct super_block *sb)
{
struct dentry *ret = NULL;
if (sb) {
static const struct qstr name = {
.name = "/",
.len = 1
};
ret = d_alloc(NULL, &name);
if (ret) {
d_set_d_op(ret, &sdcardfs_ci_dops);
ret->d_sb = sb;
ret->d_parent = ret;
}
}
return ret;
}
#endif
DEFINE_MUTEX(sdcardfs_super_list_lock);
LIST_HEAD(sdcardfs_super_list);
EXPORT_SYMBOL_GPL(sdcardfs_super_list_lock);
EXPORT_SYMBOL_GPL(sdcardfs_super_list);
/*
* There is no need to lock the sdcardfs_super_info's rwsem as there is no
* way anyone can have a reference to the superblock at this point in time.
*/
static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
void *raw_data, int silent)
{
int err = 0;
int debug;
struct super_block *lower_sb;
struct path lower_path;
struct sdcardfs_sb_info *sb_info;
struct inode *inode;
printk(KERN_INFO "sdcardfs version 2.0\n");
if (!dev_name) {
printk(KERN_ERR
"sdcardfs: read_super: missing dev_name argument\n");
err = -EINVAL;
goto out;
}
printk(KERN_INFO "sdcardfs: dev_name -> %s\n", dev_name);
printk(KERN_INFO "sdcardfs: options -> %s\n", (char *)raw_data);
/* parse lower path */
err = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
&lower_path);
if (err) {
printk(KERN_ERR "sdcardfs: error accessing lower directory '%s'\n", dev_name);
goto out;
}
/* allocate superblock private data */
sb->s_fs_info = kzalloc(sizeof(struct sdcardfs_sb_info), GFP_KERNEL);
if (!SDCARDFS_SB(sb)) {
printk(KERN_CRIT "sdcardfs: read_super: out of memory\n");
err = -ENOMEM;
goto out_free;
}
sb_info = sb->s_fs_info;
/* parse options */
err = parse_options(sb, raw_data, silent, &debug, &sb_info->options);
if (err) {
printk(KERN_ERR "sdcardfs: invalid options\n");
goto out_freesbi;
}
/* set the lower superblock field of upper superblock */
lower_sb = lower_path.dentry->d_sb;
atomic_inc(&lower_sb->s_active);
sdcardfs_set_lower_super(sb, lower_sb);
/* inherit maxbytes from lower file system */
sb->s_maxbytes = lower_sb->s_maxbytes;
/*
* Our c/m/atime granularity is 1 ns because we may stack on file
* systems whose granularity is as good.
*/
sb->s_time_gran = 1;
sb->s_magic = SDCARDFS_SUPER_MAGIC;
sb->s_op = &sdcardfs_sops;
/* get a new inode and allocate our root dentry */
inode = sdcardfs_iget(sb, lower_path.dentry->d_inode, 0);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
goto out_sput;
}
sb->s_root = d_make_root(inode);
if (!sb->s_root) {
err = -ENOMEM;
goto out_iput;
}
d_set_d_op(sb->s_root, &sdcardfs_ci_dops);
/* link the upper and lower dentries */
sb->s_root->d_fsdata = NULL;
err = new_dentry_private_data(sb->s_root);
if (err)
goto out_freeroot;
/* set the lower dentries for s_root */
sdcardfs_set_lower_path(sb->s_root, &lower_path);
/*
* No need to call interpose because we already have a positive
* dentry, which was instantiated by d_make_root. Just need to
* d_rehash it.
*/
d_rehash(sb->s_root);
/* setup permission policy */
sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
mutex_lock(&sdcardfs_super_list_lock);
if(sb_info->options.multiuser) {
setup_derived_state(sb->s_root->d_inode, PERM_PRE_ROOT, sb_info->options.fs_user_id, AID_ROOT, false, sb->s_root->d_inode);
snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name);
/*err = prepare_dir(sb_info->obbpath_s,
sb_info->options.fs_low_uid,
sb_info->options.fs_low_gid, 00755);*/
} else {
setup_derived_state(sb->s_root->d_inode, PERM_ROOT, sb_info->options.fs_user_id, AID_ROOT, false, sb->s_root->d_inode);
snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name);
}
fix_derived_permission(sb->s_root->d_inode);
sb_info->sb = sb;
list_add(&sb_info->list, &sdcardfs_super_list);
mutex_unlock(&sdcardfs_super_list_lock);
if (!silent)
printk(KERN_INFO "sdcardfs: mounted on top of %s type %s\n",
dev_name, lower_sb->s_type->name);
goto out; /* all is well */
/* no longer needed: free_dentry_private_data(sb->s_root); */
out_freeroot:
dput(sb->s_root);
out_iput:
iput(inode);
out_sput:
/* drop refs we took earlier */
atomic_dec(&lower_sb->s_active);
out_freesbi:
kfree(SDCARDFS_SB(sb));
sb->s_fs_info = NULL;
out_free:
path_put(&lower_path);
out:
return err;
}
