/*
* Lookup one path component @name relative to a <base,mnt> path pair.
* Behaves nearly the same as lookup_one_len (i.e., return negative dentry
* on ENOENT), but uses the @mnt passed, so it can cross bind mounts and
* other lower mounts properly. If @new_mnt is non-null, will fill in the
* new mnt there. Caller is responsible to dput/mntput/path_put returned
* @dentry and @new_mnt.
*/
struct dentry *__lookup_one(struct dentry *base, struct vfsmount *mnt,
const char *name, struct vfsmount **new_mnt)
{
struct dentry *dentry = NULL;
struct nameidata lower_nd;
int err;
/* we use flags=0 to get basic lookup */
err = vfs_path_lookup(base, mnt, name, 0, &lower_nd);
switch (err) {
case 0: /* no error */
dentry = lower_nd.path.dentry;
if (new_mnt)
*new_mnt = lower_nd.path.mnt; /* rc already inc'ed */
break;
case -ENOENT:
/*
* We don't consider ENOENT an error, and we want to return
* a negative dentry (ala lookup_one_len). As we know
* there was no inode for this name before (-ENOENT), then
* it's safe to call lookup_one_len (which doesn't take a
* vfsmount).
*/
dentry = lookup_one_len(name, base, strlen(name));
if (new_mnt)
*new_mnt = mntget(lower_nd.path.mnt);
break;
default: /* all other real errors */
dentry = ERR_PTR(err);
break;
}
return dentry;
}
/**
* Prepares a directory operation by taking the mutex on the parent inode of
* an entry and returning a dentry for the entry.
*
* @param child_name path to the entry, assumed absolute from configfs
* scheduler subsystem entry.
*
* @return a valid dentry to the target entry, or error. The valid
* dentry must be released with put_child_dentry.
*/
static struct dentry *get_child_dentry(const char *child_name)
{
struct dentry *d_dir;
struct dentry *d_child;
const char *last_child_comp;
const char *real_child_name = child_name;
int err;
d_dir = dget(krg_scheduler_subsys.su_group.cg_item.ci_dentry);
last_child_comp = strrchr(child_name, '/');
if (last_child_comp) {
struct nameidata nd;
err = vfs_path_lookup(d_dir, scheduler_fs_mount,
child_name, LOOKUP_PARENT, &nd);
dput(d_dir);
if (err)
return ERR_PTR(err);
d_dir = dget(nd.path.dentry);
path_put(&nd.path);
BUG_ON(!last_child_comp[1]);
real_child_name = last_child_comp + 1;
}
mutex_lock_nested(&d_dir->d_inode->i_mutex, I_MUTEX_PARENT);
d_child = lookup_one_len(real_child_name, d_dir, strlen(real_child_name));
if (IS_ERR(d_child))
mutex_unlock(&d_dir->d_inode->i_mutex);
dput(d_dir);
return d_child;
}
static int dev_mkdir(const char *name, mode_t mode)
{
struct nameidata nd;
struct dentry *dentry;
int err;
err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
name, LOOKUP_PARENT, &nd);
if (err)
return err;
dentry = lookup_create(&nd, 1);
if (!IS_ERR(dentry)) {
err = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);
if (!err)
/* mark as kernel-created inode */
dentry->d_inode->i_private = &dev_mnt;
dput(dentry);
} else {
err = PTR_ERR(dentry);
}
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
return err;
}
static int dev_rmdir(const char *name)
{
struct nameidata nd;
struct dentry *dentry;
int err;
err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
name, LOOKUP_PARENT, &nd);
if (err)
return err;
mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
dentry = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len);
if (!IS_ERR(dentry)) {
if (dentry->d_inode) {
if (dentry->d_inode->i_private == &dev_mnt)
err = vfs_rmdir(nd.path.dentry->d_inode,
dentry);
else
err = -EPERM;
} else {
err = -ENOENT;
}
dput(dentry);
} else {
err = PTR_ERR(dentry);
}
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
return err;
}
static struct file *do_open(char *name, int flags)
{
struct nameidata nd;
struct vfsmount *mnt;
int error;
mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
if (IS_ERR(mnt))
return (struct file *)mnt;
error = vfs_path_lookup(mnt->mnt_root, mnt, name, 0, &nd);
mntput(mnt); /* drop do_kern_mount reference */
if (error)
return ERR_PTR(error);
if (flags == O_RDWR)
error = may_open(&nd,MAY_READ|MAY_WRITE,FMODE_READ|FMODE_WRITE);
else
error = may_open(&nd, MAY_WRITE, FMODE_WRITE);
if (!error)
return dentry_open(nd.path.dentry, nd.path.mnt, flags);
path_put(&nd.path);
return ERR_PTR(error);
}
/**
* ecryptfs_lookup_one_lower
* @ecryptfs_dentry: The eCryptfs dentry that we are looking up
* @lower_dir_dentry: lower parent directory
*
* Get the lower dentry from vfs. If lower dentry does not exist yet,
* create it.
*/
static struct dentry *
ecryptfs_lookup_one_lower(struct dentry *ecryptfs_dentry,
struct dentry *lower_dir_dentry)
{
struct nameidata nd;
struct vfsmount *lower_mnt;
struct qstr *name;
int err;
name = &ecryptfs_dentry->d_name;
lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
ecryptfs_dentry->d_parent));
err = vfs_path_lookup(lower_dir_dentry, lower_mnt, name->name , 0, &nd);
mntput(lower_mnt);
if (!err) {
/* we dont need the mount */
mntput(nd.path.mnt);
return nd.path.dentry;
}
if (err != -ENOENT)
return ERR_PTR(err);
/* create a new lower dentry */
return ecryptfs_new_lower_dentry(name, lower_dir_dentry, &nd);
}
/**
* Look up for a file (or directory) in VFS.
*/
static struct dentry *
lookup_file(const char *path, struct dentry *parent)
{
int ret;
struct path p;
BUG_ON(!parent);
ret = vfs_path_lookup(parent, NULL, path, 0, &p);
return (ret ? NULL : p.dentry);
}
int devtmpfs_delete_node(struct device *dev)
{
const char *tmp = NULL;
const char *nodename;
const struct cred *curr_cred;
struct nameidata nd;
struct dentry *dentry;
struct kstat stat;
int deleted = 1;
int err;
if (!dev_mnt)
return 0;
nodename = device_get_devnode(dev, NULL, &tmp);
if (!nodename)
return -ENOMEM;
curr_cred = override_creds(&init_cred);
err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
nodename, LOOKUP_PARENT, &nd);
if (err)
goto out;
mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
dentry = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len);
if (!IS_ERR(dentry)) {
if (dentry->d_inode) {
err = vfs_getattr(nd.path.mnt, dentry, &stat);
if (!err && dev_mynode(dev, dentry->d_inode, &stat)) {
err = vfs_unlink(nd.path.dentry->d_inode,
dentry);
if (!err || err == -ENOENT)
deleted = 1;
}
} else {
err = -ENOENT;
}
dput(dentry);
} else {
err = PTR_ERR(dentry);
}
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
if (deleted && strchr(nodename, '/'))
delete_path(nodename);
out:
kfree(tmp);
revert_creds(curr_cred);
return err;
}
void syscall_chdir(uint32_t *ebx, uint32_t *ecx, uint32_t *edx) {
const char *path = (const char*) *ebx;
vfs_inode_t *inode = vfs_path_lookup(path);
if(inode != NULL) {
if(S_ISDIR(inode->stat)) {
current_proc->work_dir = inode;
*ecx = 0;
} else {
*ecx = -1;
}
} else {
*ecx = -2;
}
}
static int create_path(const char *nodepath)
{
char *path;
struct nameidata nd;
int err = 0;
struct vfsmount *dev_mnt = ve_devmnt();
path = kstrdup(nodepath, GFP_KERNEL);
if (!path)
return -ENOMEM;
err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
path, LOOKUP_PARENT, &nd);
if (err == 0) {
struct dentry *dentry;
/* create directory right away */
dentry = lookup_create(&nd, 1);
if (!IS_ERR(dentry)) {
err = vfs_mkdir(nd.path.dentry->d_inode,
dentry, 0755);
dput(dentry);
}
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
} else if (err == -ENOENT) {
char *s;
/* parent directories do not exist, create them */
s = path;
while (1) {
s = strchr(s, '/');
if (!s)
break;
s[0] = '\0';
err = dev_mkdir(path, 0755);
if (err && err != -EEXIST)
break;
s[0] = '/';
s++;
}
}
kfree(path);
return err;
}
int nfs_cache_register(struct cache_detail *cd)
{
struct nameidata nd;
struct vfsmount *mnt;
int ret;
mnt = rpc_get_mount();
if (IS_ERR(mnt))
return PTR_ERR(mnt);
ret = vfs_path_lookup(mnt->mnt_root, mnt, "/cache", 0, &nd);
if (ret)
goto err;
ret = sunrpc_cache_register_pipefs(nd.path.dentry,
cd->name, 0600, cd);
path_put(&nd.path);
if (!ret)
return ret;
err:
rpc_put_mount();
return ret;
}
void syscall_open(uint32_t *ebx, uint32_t *ecx, uint32_t *edx) {
const char *path = (const char*) *ebx;
int oflags = *ecx;
mode_t mode = *edx;
vfs_inode_t *inode = vfs_path_lookup(path);
fd_t fd = proc_get_unused_fd(current_proc);
if(inode == NULL) {
if(oflags & O_CREAT) {// create inode
// TODO: what if here is a path with subdirs given?
char *name = malloc(strlen((char*)path));
strcpy(name, path);
inode = vfs_create_inode(name, mode, vfs_root());
} else {
*ebx = -1;
return;
}
} else {
if(oflags & O_EXCL) {
*ebx = -1;
return;
}
}
if(oflags & O_TRUNC) {
memclr(inode->base, inode->length);
}
current_proc->fd[fd]->inode = inode;
current_proc->fd[fd]->flags = oflags;
current_proc->fd[fd]->mode = mode;
current_proc->fd[fd]->pos = 0;
*ebx = fd;
}
int devtmpfs_delete_node(struct device *dev)
{
const char *tmp = NULL;
const char *nodename;
const struct cred *curr_cred;
struct nameidata nd;
struct dentry *dentry;
struct kstat stat;
int deleted = 1;
int err;
if (!dev_mnt)
return 0;
nodename = device_get_devnode(dev, NULL, &tmp);
if (!nodename)
return -ENOMEM;
curr_cred = override_creds(&init_cred);
err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
nodename, LOOKUP_PARENT, &nd);
if (err)
goto out;
mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
dentry = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len);
if (!IS_ERR(dentry)) {
if (dentry->d_inode) {
err = vfs_getattr(nd.path.mnt, dentry, &stat);
if (!err && dev_mynode(dev, dentry->d_inode, &stat)) {
struct iattr newattrs;
/*
* before unlinking this node, reset permissions
* of possible references like hardlinks
*/
newattrs.ia_uid = 0;
newattrs.ia_gid = 0;
newattrs.ia_mode = stat.mode & ~0777;
newattrs.ia_valid =
ATTR_UID|ATTR_GID|ATTR_MODE;
mutex_lock(&dentry->d_inode->i_mutex);
notify_change(dentry, &newattrs);
mutex_unlock(&dentry->d_inode->i_mutex);
err = vfs_unlink(nd.path.dentry->d_inode,
dentry);
if (!err || err == -ENOENT)
deleted = 1;
}
} else {
err = -ENOENT;
}
dput(dentry);
} else {
err = PTR_ERR(dentry);
}
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
if (deleted && strchr(nodename, '/'))
delete_path(nodename);
out:
kfree(tmp);
revert_creds(curr_cred);
return err;
}
int devtmpfs_create_node(struct device *dev)
{
const char *tmp = NULL;
const char *nodename;
const struct cred *curr_cred;
mode_t mode = 0;
struct nameidata nd;
struct dentry *dentry;
int err;
if (!dev_mnt)
return 0;
nodename = device_get_devnode(dev, &mode, &tmp);
if (!nodename)
return -ENOMEM;
if (mode == 0)
mode = 0600;
if (is_blockdev(dev))
mode |= S_IFBLK;
else
mode |= S_IFCHR;
curr_cred = override_creds(&init_cred);
err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
nodename, LOOKUP_PARENT, &nd);
if (err == -ENOENT) {
create_path(nodename);
err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
nodename, LOOKUP_PARENT, &nd);
}
if (err)
goto out;
dentry = lookup_create(&nd, 0);
if (!IS_ERR(dentry)) {
err = vfs_mknod(nd.path.dentry->d_inode,
dentry, mode, dev->devt);
if (!err) {
struct iattr newattrs;
/* fixup possibly umasked mode */
newattrs.ia_mode = mode;
newattrs.ia_valid = ATTR_MODE;
mutex_lock(&dentry->d_inode->i_mutex);
notify_change(dentry, &newattrs);
mutex_unlock(&dentry->d_inode->i_mutex);
/* mark as kernel-created inode */
dentry->d_inode->i_private = &dev_mnt;
}
dput(dentry);
} else {
err = PTR_ERR(dentry);
}
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
out:
kfree(tmp);
revert_creds(curr_cred);
return err;
}
/*
* Main driver function for sdcardfs's lookup.
*
* Returns: NULL (ok), ERR_PTR if an error occurred.
* Fills in lower_parent_path with <dentry,mnt> on success.
*/
static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
struct nameidata *nd, struct path *lower_parent_path)
{
int err = 0;
struct vfsmount *lower_dir_mnt;
struct dentry *lower_dir_dentry = NULL;
struct dentry *lower_dentry;
const char *name;
struct path lower_path;
struct qstr this;
/* must initialize dentry operations */
d_set_d_op(dentry, &sdcardfs_dops);
if (IS_ROOT(dentry))
goto out;
name = dentry->d_name.name;
/* now start the actual lookup procedure */
lower_dir_dentry = lower_parent_path->dentry;
lower_dir_mnt = lower_parent_path->mnt;
/* Use vfs_path_lookup to check if the dentry exists or not */
err = vfs_path_lookup(lower_dir_dentry, lower_dir_mnt, name, 0,
&lower_path);
/* no error: handle positive dentries */
if (!err) {
#ifdef SDCARDFS_CASE_INSENSITIVE_MATCH_SUPPORT
dentry_found:
#endif
sdcardfs_set_lower_path(dentry, &lower_path);
err = sdcardfs_interpose(dentry, dentry->d_sb, &lower_path);
if (err) /* path_put underlying path on error */
sdcardfs_put_reset_lower_path(dentry);
goto out;
}
#ifdef SDCARDFS_CASE_INSENSITIVE_MATCH_SUPPORT
if (err == -ENOENT) {
/* try case insensetive match */
char * match_name = NULL;
match_name = find_case_insensitive(lower_parent_path, name);
if (unlikely(IS_ERR(match_name))) {
err = PTR_ERR(match_name);
} else if (match_name) {
/* found */
err = vfs_path_lookup(lower_dir_dentry, lower_dir_mnt,
match_name, 0, &lower_path);
kfree(match_name);
if (!err)
goto dentry_found;
}
/* no match */
}
#endif
/*
* We don't consider ENOENT an error, and we want to return a
* negative dentry.
*/
if (err && err != -ENOENT)
goto out;
/* instatiate a new negative dentry */
this.name = name;
this.len = strlen(name);
this.hash = full_name_hash(this.name, this.len);
lower_dentry = d_lookup(lower_dir_dentry, &this);
if (lower_dentry)
goto setup_lower;
lower_dentry = d_alloc(lower_dir_dentry, &this);
if (!lower_dentry) {
err = -ENOMEM;
goto out;
}
d_add(lower_dentry, NULL); /* instantiate and hash */
setup_lower:
lower_path.dentry = lower_dentry;
lower_path.mnt = mntget(lower_dir_mnt);
sdcardfs_set_lower_path(dentry, &lower_path);
/*
* If the intent is to create a file, then don't return an error, so
* the VFS will continue the process of making this negative dentry
* into a positive one.
*/
if (nd) {
if (nd->flags & (LOOKUP_CREATE|LOOKUP_RENAME_TARGET))
err = 0;
} else
err = 0;
out:
return ERR_PTR(err);
}
/*
* Safely creates '/proc/systemtap' (if necessary) and
* '/proc/systemtap/{module_name}'.
*
* NB: this function is suitable to call from early in the the
* module-init function, and doesn't rely on any other facilities
* in our runtime. PR19833. See also PR15408.
*/
static int _stp_mkdir_proc_module(void)
{
int found = 0;
static char proc_root_name[STP_MODULE_NAME_LEN + sizeof("systemtap/")];
#if defined(STAPCONF_PATH_LOOKUP) || defined(STAPCONF_KERN_PATH_PARENT)
struct nameidata nd;
#else /* STAPCONF_VFS_PATH_LOOKUP or STAPCONF_KERN_PATH */
struct path path;
#if defined(STAPCONF_VFS_PATH_LOOKUP)
struct vfsmount *mnt;
#endif
int rc;
#endif /* STAPCONF_VFS_PATH_LOOKUP or STAPCONF_KERN_PATH */
if (_stp_proc_root != NULL)
return 0;
#if defined(STAPCONF_PATH_LOOKUP) || defined(STAPCONF_KERN_PATH_PARENT)
/* Why "/proc/systemtap/foo"? kern_path_parent() is basically
* the same thing as calling the old path_lookup() with flags
* set to LOOKUP_PARENT, which means to look up the parent of
* the path, which in this case is "/proc/systemtap". */
if (! kern_path_parent("/proc/systemtap/foo", &nd)) {
found = 1;
#ifdef STAPCONF_NAMEIDATA_CLEANUP
path_put(&nd.path);
#else /* !STAPCONF_NAMEIDATA_CLEANUP */
path_release(&nd);
#endif /* !STAPCONF_NAMEIDATA_CLEANUP */
}
#elif defined(STAPCONF_KERN_PATH)
/* Prefer kern_path() over vfs_path_lookup(), since on some
* kernels the declaration for vfs_path_lookup() was moved to
* a private header. */
/* See if '/proc/systemtap' exists. */
rc = kern_path("/proc/systemtap", 0, &path);
if (rc == 0) {
found = 1;
path_put (&path);
}
#else /* STAPCONF_VFS_PATH_LOOKUP */
/* See if '/proc/systemtap' exists. */
if (! init_pid_ns.proc_mnt) {
errk("Unable to create '/proc/systemap':"
" '/proc' doesn't exist.\n");
goto done;
}
mnt = init_pid_ns.proc_mnt;
rc = vfs_path_lookup(mnt->mnt_root, mnt, "systemtap", 0, &path);
if (rc == 0) {
found = 1;
path_put (&path);
}
#endif /* STAPCONF_VFS_PATH_LOOKUP */
/* If we couldn't find "/proc/systemtap", create it. */
if (!found) {
struct proc_dir_entry *de;
de = proc_mkdir ("systemtap", NULL);
if (de == NULL) {
errk("Unable to create '/proc/systemap':"
" proc_mkdir failed.\n");
goto done;
}
}
/* Create the "systemtap/{module_name} directory in procfs. */
strlcpy(proc_root_name, "systemtap/", sizeof(proc_root_name));
strlcat(proc_root_name, THIS_MODULE->name, sizeof(proc_root_name));
_stp_proc_root = proc_mkdir(proc_root_name, NULL);
#ifdef STAPCONF_PROCFS_OWNER
if (_stp_proc_root != NULL)
_stp_proc_root->owner = THIS_MODULE;
#endif
if (_stp_proc_root == NULL)
errk("Unable to create '/proc/systemap/%s':"
" proc_mkdir failed.\n", THIS_MODULE->name);
done:
return (_stp_proc_root) ? 0 : -EINVAL;
}
/*
* Main driver function for sdcardfskk's lookup.
*
* Returns: NULL (ok), ERR_PTR if an error occurred.
* Fills in lower_parent_path with <dentry,mnt> on success.
*/
static struct dentry *__sdcardfskk_lookup(struct dentry *dentry,
struct nameidata *nd, struct path *lower_parent_path)
{
int err = 0;
struct vfsmount *lower_dir_mnt;
struct dentry *lower_dir_dentry = NULL;
struct dentry *lower_dentry;
const char *name;
struct nameidata lower_nd;
struct path lower_path;
struct qstr this;
struct sdcardfskk_sb_info *sbi;
sbi = SDCARDFSKK_SB(dentry->d_sb);
/* must initialize dentry operations */
d_set_d_op(dentry, &sdcardfskk_ci_dops);
if (IS_ROOT(dentry))
goto out;
name = dentry->d_name.name;
/* now start the actual lookup procedure */
lower_dir_dentry = lower_parent_path->dentry;
lower_dir_mnt = lower_parent_path->mnt;
/* Use vfs_path_lookup to check if the dentry exists or not */
if (sbi->options.lower_fs == LOWER_FS_EXT4) {
err = vfs_path_lookup(lower_dir_dentry, lower_dir_mnt, name,
LOOKUP_CASE_INSENSITIVE, &lower_nd);
} else if (sbi->options.lower_fs == LOWER_FS_FAT) {
err = vfs_path_lookup(lower_dir_dentry, lower_dir_mnt, name, 0,
&lower_nd);
}
/* no error: handle positive dentries */
if (!err) {
/* check if the dentry is an obb dentry
* if true, the lower_inode must be replaced with
* the inode of the graft path */
if(need_graft_path_kitkat(dentry)) {
/* setup_obb_dentry_kitkat()
* The lower_path will be stored to the dentry's orig_path
* and the base obbpath will be copyed to the lower_path variable.
* if an error returned, there's no change in the lower_path
* returns: -ERRNO if error (0: no error) */
err = setup_obb_dentry_kitkat(dentry, &lower_nd.path);
if(err) {
/* if the sbi->obbpath is not available, we can optionally
* setup the lower_path with its orig_path.
* but, the current implementation just returns an error
* because the sdcard daemon also regards this case as
* a lookup fail. */
printk(KERN_INFO "sdcardfskk: base obbpath is not available\n");
sdcardfskk_put_reset_orig_path(dentry);
goto out;
}
}
sdcardfskk_set_lower_path(dentry, &lower_nd.path);
err = sdcardfskk_interpose(dentry, dentry->d_sb, &lower_nd.path);
if (err) /* path_put underlying path on error */
sdcardfskk_put_reset_lower_path(dentry);
goto out;
}
/*
* We don't consider ENOENT an error, and we want to return a
* negative dentry.
*/
if (err && err != -ENOENT)
goto out;
/* instatiate a new negative dentry */
this.name = name;
this.len = strlen(name);
this.hash = full_name_hash(this.name, this.len);
lower_dentry = d_lookup(lower_dir_dentry, &this);
if (lower_dentry)
goto setup_lower;
lower_dentry = d_alloc(lower_dir_dentry, &this);
if (!lower_dentry) {
err = -ENOMEM;
goto out;
}
d_add(lower_dentry, NULL); /* instantiate and hash */
setup_lower:
lower_path.dentry = lower_dentry;
lower_path.mnt = mntget(lower_dir_mnt);
sdcardfskk_set_lower_path(dentry, &lower_path);
/*
* If the intent is to create a file, then don't return an error, so
* the VFS will continue the process of making this negative dentry
* into a positive one.
*/
if (nd) {
if (nd->flags & (LOOKUP_CREATE|LOOKUP_RENAME_TARGET))
err = 0;
} else
err = 0;
out:
return ERR_PTR(err);
}
/*
* Main driver function for wrapfs's lookup.
*
* Returns: NULL (ok), ERR_PTR if an error occurred.
* Fills in lower_parent_path with <dentry,mnt> on success.
*/
static struct dentry *__wrapfs_lookup(struct dentry *dentry, int flags,
struct path *lower_parent_path)
{
int err = 0;
struct vfsmount *lower_dir_mnt;
struct dentry *lower_dir_dentry = NULL;
struct dentry *lower_dentry;
const char *name;
struct path lower_path;
struct qstr this;
/* must initialize dentry operations */
d_set_d_op(dentry, &wrapfs_dops);
if (IS_ROOT(dentry))
goto out;
name = dentry->d_name.name;
/* now start the actual lookup procedure */
lower_dir_dentry = lower_parent_path->dentry;
lower_dir_mnt = lower_parent_path->mnt;
/* Use vfs_path_lookup to check if the dentry exists or not */
err = vfs_path_lookup(lower_dir_dentry, lower_dir_mnt, name, 0,
&lower_path);
/* no error: handle positive dentries */
if (!err) {
wrapfs_set_lower_path(dentry, &lower_path);
err = wrapfs_interpose(dentry, dentry->d_sb, &lower_path);
if (err) /* path_put underlying path on error */
wrapfs_put_reset_lower_path(dentry);
goto out;
}
/*
* We don't consider ENOENT an error, and we want to return a
* negative dentry.
*/
if (err && err != -ENOENT)
goto out;
/* instatiate a new negative dentry */
this.name = name;
this.len = strlen(name);
this.hash = full_name_hash(this.name, this.len);
lower_dentry = d_lookup(lower_dir_dentry, &this);
if (lower_dentry)
goto setup_lower;
lower_dentry = d_alloc(lower_dir_dentry, &this);
if (!lower_dentry) {
err = -ENOMEM;
goto out;
}
d_add(lower_dentry, NULL); /* instantiate and hash */
setup_lower:
lower_path.dentry = lower_dentry;
lower_path.mnt = mntget(lower_dir_mnt);
wrapfs_set_lower_path(dentry, &lower_path);
/*
* If the intent is to create a file, then don't return an error, so
* the VFS will continue the process of making this negative dentry
* into a positive one.
*/
if (flags & (LOOKUP_CREATE|LOOKUP_RENAME_TARGET))
err = 0;
out:
return ERR_PTR(err);
}
int devtmpfs_create_node(struct device *dev)
{
const char *tmp = NULL;
const char *nodename;
const struct cred *curr_cred;
struct user_beancounter *curr_ub;
mode_t mode = 0;
struct nameidata nd;
struct dentry *dentry;
int err;
struct vfsmount *dev_mnt = ve_devmnt();
if (!dev_mnt)
return 0;
nodename = device_get_devnode(dev, &mode, &tmp);
if (!nodename)
return -ENOMEM;
if (mode == 0)
mode = 0600;
if (is_blockdev(dev))
mode |= S_IFBLK;
else
mode |= S_IFCHR;
curr_ub = set_exec_ub(&ub0);
curr_cred = override_creds(&init_cred);
err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
nodename, LOOKUP_PARENT, &nd);
if (err == -ENOENT) {
/* create missing parent directories */
create_path(nodename);
err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
nodename, LOOKUP_PARENT, &nd);
if (err)
goto out;
}
dentry = lookup_create(&nd, 0);
if (!IS_ERR(dentry)) {
int umask;
umask = sys_umask(0000);
err = vfs_mknod(nd.path.dentry->d_inode,
dentry, mode, dev->devt);
sys_umask(umask);
/* mark as kernel created inode */
if (!err)
dentry->d_inode->i_private = &dev_mnt;
dput(dentry);
} else {
err = PTR_ERR(dentry);
}
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
out:
kfree(tmp);
revert_creds(curr_cred);
(void)set_exec_ub(curr_ub);
return err;
}
