fs: add filp_clone_open API

I need an API that allows me to obtain a clone of the current file
pointer to pass in to an exec handler.  I've labelled this as an
internal API because I can't see how it would be useful outside of the
fs subsystem.  The use case will be a persistent binfmt_misc handler.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Jan Kara <jack@suse.cz>
This commit is contained in:
James Bottomley 2016-02-17 16:49:38 -08:00
parent f55532a0c0
commit 9a08c352d0
2 changed files with 21 additions and 0 deletions

View File

@ -108,6 +108,7 @@ extern long do_handle_open(int mountdirfd,
struct file_handle __user *ufh, int open_flag);
extern int open_check_o_direct(struct file *f);
extern int vfs_open(const struct path *, struct file *, const struct cred *);
extern struct file *filp_clone_open(struct file *);
/*
* inode.c

View File

@ -1002,6 +1002,26 @@ struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
}
EXPORT_SYMBOL(file_open_root);
struct file *filp_clone_open(struct file *oldfile)
{
struct file *file;
int retval;
file = get_empty_filp();
if (IS_ERR(file))
return file;
file->f_flags = oldfile->f_flags;
retval = vfs_open(&oldfile->f_path, file, oldfile->f_cred);
if (retval) {
put_filp(file);
return ERR_PTR(retval);
}
return file;
}
EXPORT_SYMBOL(filp_clone_open);
long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
{
struct open_flags op;