return retval;
}
-char * getname(const char __user * filename)
+static char *getname_flags(const char __user * filename, int flags)
{
char *tmp, *result;
result = tmp;
if (retval < 0) {
- __putname(tmp);
- result = ERR_PTR(retval);
+ if (retval != -ENOENT || !(flags & LOOKUP_EMPTY)) {
+ __putname(tmp);
+ result = ERR_PTR(retval);
+ }
}
}
audit_getname(result);
return result;
}
+char *getname(const char __user * filename)
+{
+ return getname_flags(filename, 0);
+}
+
#ifdef CONFIG_AUDITSYSCALL
void putname(const char *name)
{
{
struct fs_struct *fs = current->fs;
struct dentry *dentry = nd->path.dentry;
+ int want_root = 0;
BUG_ON(!(nd->flags & LOOKUP_RCU));
- if (nd->root.mnt) {
+ if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
+ want_root = 1;
spin_lock(&fs->lock);
if (nd->root.mnt != fs->root.mnt ||
nd->root.dentry != fs->root.dentry)
goto err;
BUG_ON(nd->inode != dentry->d_inode);
spin_unlock(&dentry->d_lock);
- if (nd->root.mnt) {
+ if (want_root) {
path_get(&nd->root);
spin_unlock(&fs->lock);
}
err:
spin_unlock(&dentry->d_lock);
err_root:
- if (nd->root.mnt)
+ if (want_root)
spin_unlock(&fs->lock);
return -ECHILD;
}
{
struct fs_struct *fs = current->fs;
struct dentry *parent = nd->path.dentry;
+ int want_root = 0;
BUG_ON(!(nd->flags & LOOKUP_RCU));
- if (nd->root.mnt) {
+ if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
+ want_root = 1;
spin_lock(&fs->lock);
if (nd->root.mnt != fs->root.mnt ||
nd->root.dentry != fs->root.dentry)
parent->d_count++;
spin_unlock(&dentry->d_lock);
spin_unlock(&parent->d_lock);
- if (nd->root.mnt) {
+ if (want_root) {
path_get(&nd->root);
spin_unlock(&fs->lock);
}
spin_unlock(&dentry->d_lock);
spin_unlock(&parent->d_lock);
err_root:
- if (nd->root.mnt)
+ if (want_root)
spin_unlock(&fs->lock);
return -ECHILD;
}
if (nd->flags & LOOKUP_RCU) {
if (unlikely(nameidata_dentry_drop_rcu(nd, dentry))) {
nd->flags &= ~LOOKUP_RCU;
- nd->root.mnt = NULL;
+ if (!(nd->flags & LOOKUP_ROOT))
+ nd->root.mnt = NULL;
rcu_read_unlock();
br_read_unlock(vfsmount_lock);
return -ECHILD;
BUG_ON(!(nd->flags & LOOKUP_RCU));
nd->flags &= ~LOOKUP_RCU;
- nd->root.mnt = NULL;
+ if (!(nd->flags & LOOKUP_ROOT))
+ nd->root.mnt = NULL;
spin_lock(&dentry->d_lock);
if (!__d_rcu_to_refcount(dentry, nd->seq))
goto err_unlock;
return dentry;
}
-static inline struct dentry *
-do_revalidate_rcu(struct dentry *dentry, struct nameidata *nd)
-{
- int status = d_revalidate(dentry, nd);
- if (likely(status > 0))
- return dentry;
- if (status == -ECHILD) {
- if (nameidata_dentry_drop_rcu(nd, dentry))
- return ERR_PTR(-ECHILD);
- return do_revalidate(dentry, nd);
- }
- if (status < 0)
- return ERR_PTR(status);
- /* Don't d_invalidate in rcu-walk mode */
- if (nameidata_dentry_drop_rcu(nd, dentry))
- return ERR_PTR(-ECHILD);
- if (!d_invalidate(dentry)) {
- dput(dentry);
- dentry = NULL;
- }
- return dentry;
-}
-
/*
* handle_reval_path - force revalidation of a dentry
*
nd->path.dentry = path->dentry;
}
+static inline void put_link(struct nameidata *nd, struct path *link, void *cookie)
+{
+ struct inode *inode = link->dentry->d_inode;
+ if (!IS_ERR(cookie) && inode->i_op->put_link)
+ inode->i_op->put_link(link->dentry, nd, cookie);
+ path_put(link);
+}
+
static __always_inline int
-__do_follow_link(const struct path *link, struct nameidata *nd, void **p)
+follow_link(struct path *link, struct nameidata *nd, void **p)
{
int error;
struct dentry *dentry = link->dentry;
BUG_ON(nd->flags & LOOKUP_RCU);
+ if (unlikely(current->total_link_count >= 40)) {
+ *p = ERR_PTR(-ELOOP); /* no ->put_link(), please */
+ path_put_conditional(link, nd);
+ path_put(&nd->path);
+ return -ELOOP;
+ }
+ cond_resched();
+ current->total_link_count++;
+
touch_atime(link->mnt, dentry);
nd_set_link(nd, NULL);
error = 0;
if (s)
error = __vfs_follow_link(nd, s);
- else if (nd->last_type == LAST_BIND)
+ else if (nd->last_type == LAST_BIND) {
nd->flags |= LOOKUP_JUMPED;
+ nd->inode = nd->path.dentry->d_inode;
+ if (nd->inode->i_op->follow_link) {
+ /* stepped on a _really_ weird one */
+ path_put(&nd->path);
+ error = -ELOOP;
+ }
+ }
}
return error;
}
-/*
- * This limits recursive symlink follows to 8, while
- * limiting consecutive symlinks to 40.
- *
- * Without that kind of total limit, nasty chains of consecutive
- * symlinks can cause almost arbitrarily long lookups.
- */
-static inline int do_follow_link(struct inode *inode, struct path *path, struct nameidata *nd)
-{
- void *cookie;
- int err = -ELOOP;
-
- /* We drop rcu-walk here */
- if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry))
- return -ECHILD;
- BUG_ON(inode != path->dentry->d_inode);
-
- if (current->link_count >= MAX_NESTED_LINKS)
- goto loop;
- if (current->total_link_count >= 40)
- goto loop;
- BUG_ON(nd->depth >= MAX_NESTED_LINKS);
- cond_resched();
- current->link_count++;
- current->total_link_count++;
- nd->depth++;
- err = __do_follow_link(path, nd, &cookie);
- if (!IS_ERR(cookie) && path->dentry->d_inode->i_op->put_link)
- path->dentry->d_inode->i_op->put_link(path->dentry, nd, cookie);
- path_put(path);
- current->link_count--;
- nd->depth--;
- return err;
-loop:
- path_put_conditional(path, nd);
- path_put(&nd->path);
- return err;
-}
-
static int follow_up_rcu(struct path *path)
{
struct vfsmount *parent;
failed:
nd->flags &= ~LOOKUP_RCU;
- nd->root.mnt = NULL;
+ if (!(nd->flags & LOOKUP_ROOT))
+ nd->root.mnt = NULL;
rcu_read_unlock();
br_read_unlock(vfsmount_lock);
return -ECHILD;
{
struct vfsmount *mnt = nd->path.mnt;
struct dentry *dentry, *parent = nd->path.dentry;
- struct inode *dir;
+ int need_reval = 1;
+ int status = 1;
int err;
/*
*/
if (nd->flags & LOOKUP_RCU) {
unsigned seq;
-
*inode = nd->inode;
dentry = __d_lookup_rcu(parent, name, &seq, inode);
- if (!dentry) {
- if (nameidata_drop_rcu(nd))
- return -ECHILD;
- goto need_lookup;
- }
+ if (!dentry)
+ goto unlazy;
+
/* Memory barrier in read_seqcount_begin of child is enough */
if (__read_seqcount_retry(&parent->d_seq, nd->seq))
return -ECHILD;
-
nd->seq = seq;
+
if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
- dentry = do_revalidate_rcu(dentry, nd);
- if (!dentry)
- goto need_lookup;
- if (IS_ERR(dentry))
- goto fail;
- if (!(nd->flags & LOOKUP_RCU))
- goto done;
+ status = d_revalidate(dentry, nd);
+ if (unlikely(status <= 0)) {
+ if (status != -ECHILD)
+ need_reval = 0;
+ goto unlazy;
+ }
}
path->mnt = mnt;
path->dentry = dentry;
if (likely(__follow_mount_rcu(nd, path, inode, false)))
return 0;
- if (nameidata_drop_rcu(nd))
- return -ECHILD;
- /* fallthru */
+unlazy:
+ if (dentry) {
+ if (nameidata_dentry_drop_rcu(nd, dentry))
+ return -ECHILD;
+ } else {
+ if (nameidata_drop_rcu(nd))
+ return -ECHILD;
+ }
+ } else {
+ dentry = __d_lookup(parent, name);
}
- dentry = __d_lookup(parent, name);
- if (!dentry)
- goto need_lookup;
-found:
- if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
- dentry = do_revalidate(dentry, nd);
- if (!dentry)
- goto need_lookup;
- if (IS_ERR(dentry))
- goto fail;
+
+retry:
+ if (unlikely(!dentry)) {
+ struct inode *dir = parent->d_inode;
+ BUG_ON(nd->inode != dir);
+
+ mutex_lock(&dir->i_mutex);
+ dentry = d_lookup(parent, name);
+ if (likely(!dentry)) {
+ dentry = d_alloc_and_lookup(parent, name, nd);
+ if (IS_ERR(dentry)) {
+ mutex_unlock(&dir->i_mutex);
+ return PTR_ERR(dentry);
+ }
+ /* known good */
+ need_reval = 0;
+ status = 1;
+ }
+ mutex_unlock(&dir->i_mutex);
}
-done:
+ if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval)
+ status = d_revalidate(dentry, nd);
+ if (unlikely(status <= 0)) {
+ if (status < 0) {
+ dput(dentry);
+ return status;
+ }
+ if (!d_invalidate(dentry)) {
+ dput(dentry);
+ dentry = NULL;
+ need_reval = 1;
+ goto retry;
+ }
+ }
+
path->mnt = mnt;
path->dentry = dentry;
err = follow_managed(path, nd->flags);
}
*inode = path->dentry->d_inode;
return 0;
-
-need_lookup:
- dir = parent->d_inode;
- BUG_ON(nd->inode != dir);
-
- mutex_lock(&dir->i_mutex);
- /*
- * First re-do the cached lookup just in case it was created
- * while we waited for the directory semaphore, or the first
- * lookup failed due to an unrelated rename.
- *
- * This could use version numbering or similar to avoid unnecessary
- * cache lookups, but then we'd have to do the first lookup in the
- * non-racy way. However in the common case here, everything should
- * be hot in cache, so would it be a big win?
- */
- dentry = d_lookup(parent, name);
- if (likely(!dentry)) {
- dentry = d_alloc_and_lookup(parent, name, nd);
- mutex_unlock(&dir->i_mutex);
- if (IS_ERR(dentry))
- goto fail;
- goto done;
- }
- /*
- * Uhhuh! Nasty case: the cache was re-populated while
- * we waited on the semaphore. Need to revalidate.
- */
- mutex_unlock(&dir->i_mutex);
- goto found;
-
-fail:
- return PTR_ERR(dentry);
}
static inline int may_lookup(struct nameidata *nd)
path_put(&nd->path);
} else {
nd->flags &= ~LOOKUP_RCU;
- nd->root.mnt = NULL;
+ if (!(nd->flags & LOOKUP_ROOT))
+ nd->root.mnt = NULL;
rcu_read_unlock();
br_read_unlock(vfsmount_lock);
}
}
+static inline int walk_component(struct nameidata *nd, struct path *path,
+ struct qstr *name, int type, int follow)
+{
+ struct inode *inode;
+ int err;
+ /*
+ * "." and ".." are special - ".." especially so because it has
+ * to be able to know about the current root directory and
+ * parent relationships.
+ */
+ if (unlikely(type != LAST_NORM))
+ return handle_dots(nd, type);
+ err = do_lookup(nd, name, path, &inode);
+ if (unlikely(err)) {
+ terminate_walk(nd);
+ return err;
+ }
+ if (!inode) {
+ path_to_nameidata(path, nd);
+ terminate_walk(nd);
+ return -ENOENT;
+ }
+ if (unlikely(inode->i_op->follow_link) && follow) {
+ if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry))
+ return -ECHILD;
+ BUG_ON(inode != path->dentry->d_inode);
+ return 1;
+ }
+ path_to_nameidata(path, nd);
+ nd->inode = inode;
+ return 0;
+}
+
+/*
+ * This limits recursive symlink follows to 8, while
+ * limiting consecutive symlinks to 40.
+ *
+ * Without that kind of total limit, nasty chains of consecutive
+ * symlinks can cause almost arbitrarily long lookups.
+ */
+static inline int nested_symlink(struct path *path, struct nameidata *nd)
+{
+ int res;
+
+ BUG_ON(nd->depth >= MAX_NESTED_LINKS);
+ if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
+ path_put_conditional(path, nd);
+ path_put(&nd->path);
+ return -ELOOP;
+ }
+
+ nd->depth++;
+ current->link_count++;
+
+ do {
+ struct path link = *path;
+ void *cookie;
+
+ res = follow_link(&link, nd, &cookie);
+ if (!res)
+ res = walk_component(nd, path, &nd->last,
+ nd->last_type, LOOKUP_FOLLOW);
+ put_link(nd, &link, cookie);
+ } while (res > 0);
+
+ current->link_count--;
+ nd->depth--;
+ return res;
+}
+
/*
* Name resolution.
* This is the basic name resolution function, turning a pathname into
if (!*name)
return 0;
- if (nd->depth)
- lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE);
-
/* At this point we know we have a real path component. */
for(;;) {
- struct inode *inode;
unsigned long hash;
struct qstr this;
unsigned int c;
goto last_component;
while (*++name == '/');
if (!*name)
- goto last_with_slashes;
-
- /*
- * "." and ".." are special - ".." especially so because it has
- * to be able to know about the current root directory and
- * parent relationships.
- */
- if (unlikely(type != LAST_NORM)) {
- if (handle_dots(nd, type))
- return -ECHILD;
- continue;
- }
+ goto last_component;
- /* This does the actual lookups.. */
- err = do_lookup(nd, &this, &next, &inode);
- if (err)
- break;
+ err = walk_component(nd, &next, &this, type, LOOKUP_FOLLOW);
+ if (err < 0)
+ return err;
- if (inode && inode->i_op->follow_link) {
- err = do_follow_link(inode, &next, nd);
+ if (err) {
+ err = nested_symlink(&next, nd);
if (err)
return err;
- nd->inode = nd->path.dentry->d_inode;
- } else {
- path_to_nameidata(&next, nd);
- nd->inode = inode;
}
- err = -ENOENT;
- if (!nd->inode)
- break;
err = -ENOTDIR;
if (!nd->inode->i_op->lookup)
break;
continue;
/* here ends the main loop */
-last_with_slashes:
- lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
last_component:
/* Clear LOOKUP_CONTINUE iff it was previously unset */
nd->flags &= lookup_flags | ~LOOKUP_CONTINUE;
- if (lookup_flags & LOOKUP_PARENT)
- goto lookup_parent;
- if (unlikely(type != LAST_NORM))
- return handle_dots(nd, type);
- err = do_lookup(nd, &this, &next, &inode);
- if (err)
- break;
- if (inode && unlikely(inode->i_op->follow_link) &&
- (lookup_flags & LOOKUP_FOLLOW)) {
- err = do_follow_link(inode, &next, nd);
- if (err)
- return err;
- nd->inode = nd->path.dentry->d_inode;
- } else {
- path_to_nameidata(&next, nd);
- nd->inode = inode;
- }
- err = -ENOENT;
- if (!nd->inode)
- break;
- if (lookup_flags & LOOKUP_DIRECTORY) {
- err = -ENOTDIR;
- if (!nd->inode->i_op->lookup)
- break;
- }
- return 0;
-lookup_parent:
nd->last = this;
nd->last_type = type;
return 0;
nd->last_type = LAST_ROOT; /* if there are only slashes... */
nd->flags = flags | LOOKUP_JUMPED;
nd->depth = 0;
+ if (flags & LOOKUP_ROOT) {
+ struct inode *inode = nd->root.dentry->d_inode;
+ if (*name) {
+ if (!inode->i_op->lookup)
+ return -ENOTDIR;
+ retval = inode_permission(inode, MAY_EXEC);
+ if (retval)
+ return retval;
+ }
+ nd->path = nd->root;
+ nd->inode = inode;
+ if (flags & LOOKUP_RCU) {
+ br_read_lock(vfsmount_lock);
+ rcu_read_lock();
+ nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
+ } else {
+ path_get(&nd->path);
+ }
+ return 0;
+ }
+
nd->root.mnt = NULL;
if (*name=='/') {
} else {
struct dentry *dentry;
- file = fget_light(dfd, &fput_needed);
+ file = fget_raw_light(dfd, &fput_needed);
retval = -EBADF;
if (!file)
goto out_fail;
dentry = file->f_path.dentry;
- retval = -ENOTDIR;
- if (!S_ISDIR(dentry->d_inode->i_mode))
- goto fput_fail;
+ if (*name) {
+ retval = -ENOTDIR;
+ if (!S_ISDIR(dentry->d_inode->i_mode))
+ goto fput_fail;
- retval = file_permission(file, MAY_EXEC);
- if (retval)
- goto fput_fail;
+ retval = file_permission(file, MAY_EXEC);
+ if (retval)
+ goto fput_fail;
+ }
nd->path = file->f_path;
if (flags & LOOKUP_RCU) {
return retval;
}
+static inline int lookup_last(struct nameidata *nd, struct path *path)
+{
+ if (nd->last_type == LAST_NORM && nd->last.name[nd->last.len])
+ nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
+
+ nd->flags &= ~LOOKUP_PARENT;
+ return walk_component(nd, path, &nd->last, nd->last_type,
+ nd->flags & LOOKUP_FOLLOW);
+}
+
/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
static int path_lookupat(int dfd, const char *name,
unsigned int flags, struct nameidata *nd)
{
struct file *base = NULL;
- int retval;
+ struct path path;
+ int err;
/*
* Path walking is largely split up into 2 different synchronisation
* be handled by restarting a traditional ref-walk (which will always
* be able to complete).
*/
- retval = path_init(dfd, name, flags, nd, &base);
+ err = path_init(dfd, name, flags | LOOKUP_PARENT, nd, &base);
- if (unlikely(retval))
- return retval;
+ if (unlikely(err))
+ return err;
current->total_link_count = 0;
- retval = link_path_walk(name, nd);
+ err = link_path_walk(name, nd);
+
+ if (!err && !(flags & LOOKUP_PARENT)) {
+ err = lookup_last(nd, &path);
+ while (err > 0) {
+ void *cookie;
+ struct path link = path;
+ nd->flags |= LOOKUP_PARENT;
+ err = follow_link(&link, nd, &cookie);
+ if (!err)
+ err = lookup_last(nd, &path);
+ put_link(nd, &link, cookie);
+ }
+ }
if (nd->flags & LOOKUP_RCU) {
/* went all way through without dropping RCU */
- BUG_ON(retval);
+ BUG_ON(err);
if (nameidata_drop_rcu_last(nd))
- retval = -ECHILD;
+ err = -ECHILD;
}
- if (!retval)
- retval = handle_reval_path(nd);
+ if (!err)
+ err = handle_reval_path(nd);
+
+ if (!err && nd->flags & LOOKUP_DIRECTORY) {
+ if (!nd->inode->i_op->lookup) {
+ path_put(&nd->path);
+ return -ENOTDIR;
+ }
+ }
if (base)
fput(base);
- if (nd->root.mnt) {
+ if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
path_put(&nd->root);
nd->root.mnt = NULL;
}
- return retval;
+ return err;
}
static int do_path_lookup(int dfd, const char *name,
const char *name, unsigned int flags,
struct nameidata *nd)
{
- int result;
-
- /* same as do_path_lookup */
- nd->last_type = LAST_ROOT;
- nd->flags = flags | LOOKUP_JUMPED;
- nd->depth = 0;
-
- nd->path.dentry = dentry;
- nd->path.mnt = mnt;
- path_get(&nd->path);
- nd->root = nd->path;
- path_get(&nd->root);
- nd->inode = nd->path.dentry->d_inode;
-
- current->total_link_count = 0;
-
- result = link_path_walk(name, nd);
- if (!result)
- result = handle_reval_path(nd);
- if (result == -ESTALE) {
- /* nd->path had been dropped */
- current->total_link_count = 0;
- nd->path.dentry = dentry;
- nd->path.mnt = mnt;
- nd->inode = dentry->d_inode;
- path_get(&nd->path);
- nd->flags = flags | LOOKUP_JUMPED | LOOKUP_REVAL;
-
- result = link_path_walk(name, nd);
- if (!result)
- result = handle_reval_path(nd);
- }
- if (unlikely(!result && !audit_dummy_context() && nd->path.dentry &&
- nd->inode))
- audit_inode(name, nd->path.dentry);
-
- path_put(&nd->root);
- nd->root.mnt = NULL;
-
- return result;
+ nd->root.dentry = dentry;
+ nd->root.mnt = mnt;
+ /* the first argument of do_path_lookup() is ignored with LOOKUP_ROOT */
+ return do_path_lookup(AT_FDCWD, name, flags | LOOKUP_ROOT, nd);
}
static struct dentry *__lookup_hash(struct qstr *name,
struct path *path)
{
struct nameidata nd;
- char *tmp = getname(name);
+ char *tmp = getname_flags(name, flags);
int err = PTR_ERR(tmp);
if (!IS_ERR(tmp)) {
return error;
}
-int may_open(struct path *path, int acc_mode, int flag)
+static int may_open(struct path *path, int acc_mode, int flag)
{
struct dentry *dentry = path->dentry;
struct inode *inode = dentry->d_inode;
int error;
+ /* O_PATH? */
+ if (!acc_mode)
+ return 0;
+
if (!inode)
return -ENOENT;
int open_flag = op->open_flag;
int will_truncate = open_flag & O_TRUNC;
int want_write = 0;
- int skip_perm = 0;
+ int acc_mode = op->acc_mode;
struct file *filp;
- struct inode *inode;
int error;
nd->flags &= ~LOOKUP_PARENT;
}
if (!(open_flag & O_CREAT)) {
+ int symlink_ok = 0;
if (nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
+ if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW))
+ symlink_ok = 1;
/* we _can_ be in RCU mode here */
- error = do_lookup(nd, &nd->last, path, &inode);
- if (error) {
- terminate_walk(nd);
+ error = walk_component(nd, path, &nd->last, LAST_NORM,
+ !symlink_ok);
+ if (error < 0)
return ERR_PTR(error);
- }
- if (!inode) {
- path_to_nameidata(path, nd);
- terminate_walk(nd);
- return ERR_PTR(-ENOENT);
- }
- if (unlikely(inode->i_op->follow_link)) {
- /* We drop rcu-walk here */
- if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry))
- return ERR_PTR(-ECHILD);
+ if (error) /* symlink */
return NULL;
- }
- path_to_nameidata(path, nd);
- nd->inode = inode;
/* sayonara */
if (nd->flags & LOOKUP_RCU) {
if (nameidata_drop_rcu_last(nd))
error = -ENOTDIR;
if (nd->flags & LOOKUP_DIRECTORY) {
- if (!inode->i_op->lookup)
+ if (!nd->inode->i_op->lookup)
goto exit;
}
audit_inode(pathname, nd->path.dentry);
/* Don't check for write permission, don't truncate */
open_flag &= ~O_TRUNC;
will_truncate = 0;
- skip_perm = 1;
+ acc_mode = MAY_OPEN;
error = security_path_mknod(&nd->path, dentry, mode, 0);
if (error)
goto exit_mutex_unlock;
want_write = 1;
}
common:
- error = may_open(&nd->path, skip_perm ? 0 : op->acc_mode, open_flag);
+ error = may_open(&nd->path, acc_mode, open_flag);
if (error)
goto exit;
filp = nameidata_to_filp(nd);
}
static struct file *path_openat(int dfd, const char *pathname,
- const struct open_flags *op, int flags)
+ struct nameidata *nd, const struct open_flags *op, int flags)
{
struct file *base = NULL;
struct file *filp;
- struct nameidata nd;
struct path path;
- int count = 0;
int error;
filp = get_empty_filp();
return ERR_PTR(-ENFILE);
filp->f_flags = op->open_flag;
- nd.intent.open.file = filp;
- nd.intent.open.flags = open_to_namei_flags(op->open_flag);
- nd.intent.open.create_mode = op->mode;
+ nd->intent.open.file = filp;
+ nd->intent.open.flags = open_to_namei_flags(op->open_flag);
+ nd->intent.open.create_mode = op->mode;
- error = path_init(dfd, pathname, flags | LOOKUP_PARENT, &nd, &base);
+ error = path_init(dfd, pathname, flags | LOOKUP_PARENT, nd, &base);
if (unlikely(error))
goto out_filp;
current->total_link_count = 0;
- error = link_path_walk(pathname, &nd);
+ error = link_path_walk(pathname, nd);
if (unlikely(error))
goto out_filp;
- filp = do_last(&nd, &path, op, pathname);
+ filp = do_last(nd, &path, op, pathname);
while (unlikely(!filp)) { /* trailing symlink */
struct path link = path;
- struct inode *linki = link.dentry->d_inode;
void *cookie;
- if (!(nd.flags & LOOKUP_FOLLOW) || count++ == 32) {
- path_put_conditional(&path, &nd);
- path_put(&nd.path);
+ if (!(nd->flags & LOOKUP_FOLLOW)) {
+ path_put_conditional(&path, nd);
+ path_put(&nd->path);
filp = ERR_PTR(-ELOOP);
break;
}
- /*
- * This is subtle. Instead of calling do_follow_link() we do
- * the thing by hands. The reason is that this way we have zero
- * link_count and path_walk() (called from ->follow_link)
- * honoring LOOKUP_PARENT. After that we have the parent and
- * last component, i.e. we are in the same situation as after
- * the first path_walk(). Well, almost - if the last component
- * is normal we get its copy stored in nd->last.name and we will
- * have to putname() it when we are done. Procfs-like symlinks
- * just set LAST_BIND.
- */
- nd.flags |= LOOKUP_PARENT;
- nd.flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
- error = __do_follow_link(&link, &nd, &cookie);
+ nd->flags |= LOOKUP_PARENT;
+ nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
+ error = follow_link(&link, nd, &cookie);
if (unlikely(error))
filp = ERR_PTR(error);
else
- filp = do_last(&nd, &path, op, pathname);
- if (!IS_ERR(cookie) && linki->i_op->put_link)
- linki->i_op->put_link(link.dentry, &nd, cookie);
- path_put(&link);
+ filp = do_last(nd, &path, op, pathname);
+ put_link(nd, &link, cookie);
}
out:
- if (nd.root.mnt)
- path_put(&nd.root);
+ if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT))
+ path_put(&nd->root);
if (base)
fput(base);
- release_open_intent(&nd);
+ release_open_intent(nd);
return filp;
out_filp:
struct file *do_filp_open(int dfd, const char *pathname,
const struct open_flags *op, int flags)
{
+ struct nameidata nd;
struct file *filp;
- filp = path_openat(dfd, pathname, op, flags | LOOKUP_RCU);
+ filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_RCU);
if (unlikely(filp == ERR_PTR(-ECHILD)))
- filp = path_openat(dfd, pathname, op, flags);
+ filp = path_openat(dfd, pathname, &nd, op, flags);
if (unlikely(filp == ERR_PTR(-ESTALE)))
- filp = path_openat(dfd, pathname, op, flags | LOOKUP_REVAL);
+ filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_REVAL);
return filp;
}
+struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
+ const char *name, const struct open_flags *op, int flags)
+{
+ struct nameidata nd;
+ struct file *file;
+
+ nd.root.mnt = mnt;
+ nd.root.dentry = dentry;
+
+ flags |= LOOKUP_ROOT;
+
+ if (dentry->d_inode->i_op->follow_link && op->intent & LOOKUP_OPEN)
+ return ERR_PTR(-ELOOP);
+
+ file = path_openat(-1, name, &nd, op, flags | LOOKUP_RCU);
+ if (unlikely(file == ERR_PTR(-ECHILD)))
+ file = path_openat(-1, name, &nd, op, flags);
+ if (unlikely(file == ERR_PTR(-ESTALE)))
+ file = path_openat(-1, name, &nd, op, flags | LOOKUP_REVAL);
+ return file;
+}
+
/**
* lookup_create - lookup a dentry, creating it if it doesn't exist
* @nd: nameidata info
return error;
mutex_lock(&inode->i_mutex);
- error = dir->i_op->link(old_dentry, dir, new_dentry);
+ /* Make sure we don't allow creating hardlink to an unlinked file */
+ if (inode->i_nlink == 0)
+ error = -ENOENT;
+ else
+ error = dir->i_op->link(old_dentry, dir, new_dentry);
mutex_unlock(&inode->i_mutex);
if (!error)
fsnotify_link(dir, inode, new_dentry);
struct dentry *new_dentry;
struct nameidata nd;
struct path old_path;
+ int how = 0;
int error;
char *to;
- if ((flags & ~AT_SYMLINK_FOLLOW) != 0)
+ if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0)
return -EINVAL;
+ /*
+ * To use null names we require CAP_DAC_READ_SEARCH
+ * This ensures that not everyone will be able to create
+ * handlink using the passed filedescriptor.
+ */
+ if (flags & AT_EMPTY_PATH) {
+ if (!capable(CAP_DAC_READ_SEARCH))
+ return -ENOENT;
+ how = LOOKUP_EMPTY;
+ }
+
+ if (flags & AT_SYMLINK_FOLLOW)
+ how |= LOOKUP_FOLLOW;
- error = user_path_at(olddfd, oldname,
- flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,
- &old_path);
+ error = user_path_at(olddfd, oldname, how, &old_path);
if (error)
return error;
projects / mv-sheeva.git / blobdiff