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Commit 5d826c84 authored by Al Viro's avatar Al Viro
Browse files

new helper: readlink_copy() 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 4efcc9ff

fs/namei.c

+5 −8
Original line number Diff line number Diff line
@@ -4297,11 +4297,9 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna 
	return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname);

}



int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link)

int readlink_copy(char __user *buffer, int buflen, const char *link)

{

	int len;



	len = PTR_ERR(link);

	int len = PTR_ERR(link);

	if (IS_ERR(link))

		goto out;
@@ -4313,7 +4311,7 @@ int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const c 
out:

	return len;

}

EXPORT_SYMBOL(vfs_readlink);

EXPORT_SYMBOL(readlink_copy);



/*

 * A helper for ->readlink().  This should be used *ONLY* for symlinks that
@@ -4331,7 +4329,7 @@ int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) 
	if (IS_ERR(cookie))

		return PTR_ERR(cookie);



	res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd));

	res = readlink_copy(buffer, buflen, nd_get_link(&nd));

	if (dentry->d_inode->i_op->put_link)

		dentry->d_inode->i_op->put_link(dentry, &nd, cookie);

	return res;
@@ -4356,8 +4354,7 @@ static char *page_getlink(struct dentry * dentry, struct page **ppage) 
int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)

{

	struct page *page = NULL;

	char *s = page_getlink(dentry, &page);

	int res = vfs_readlink(dentry,buffer,buflen,s);

	int res = readlink_copy(buffer, buflen, page_getlink(dentry, &page));

	if (page) {

		kunmap(page);

		page_cache_release(page);

fs/proc/namespaces.c

+4 −10
Original line number Diff line number Diff line
@@ -146,7 +146,7 @@ static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int bufl 
	struct task_struct *task;

	void *ns;

	char name[50];

	int len = -EACCES;

	int res = -EACCES;



	task = get_proc_task(inode);

	if (!task)
@@ -155,24 +155,18 @@ static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int bufl 
	if (!ptrace_may_access(task, PTRACE_MODE_READ))

		goto out_put_task;



	len = -ENOENT;

	res = -ENOENT;

	ns = ns_ops->get(task);

	if (!ns)

		goto out_put_task;



	snprintf(name, sizeof(name), "%s:[%u]", ns_ops->name, ns_ops->inum(ns));

	len = strlen(name);



	if (len > buflen)

		len = buflen;

	if (copy_to_user(buffer, name, len))

		len = -EFAULT;



	res = readlink_copy(buffer, buflen, name);

	ns_ops->put(ns);

out_put_task:

	put_task_struct(task);

out:

	return len;

	return res;

}



static const struct inode_operations proc_ns_link_inode_operations = {

fs/proc/self.c

+1 −1
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ static int proc_self_readlink(struct dentry *dentry, char __user *buffer, 
	if (!tgid)

		return -ENOENT;

	sprintf(tmp, "%d", tgid);

	return vfs_readlink(dentry,buffer,buflen,tmp);

	return readlink_copy(buffer, buflen, tmp);

}



static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)

fs/xfs/xfs_ioctl.c

+1 −27
Original line number Diff line number Diff line
@@ -271,32 +271,6 @@ xfs_open_by_handle( 
	return error;

}



/*

 * This is a copy from fs/namei.c:vfs_readlink(), except for removing it's

 * unused first argument.

 */

STATIC int

do_readlink(

	char __user		*buffer,

	int			buflen,

	const char		*link)

{

        int len;



	len = PTR_ERR(link);

	if (IS_ERR(link))

		goto out;



	len = strlen(link);

	if (len > (unsigned) buflen)

		len = buflen;

	if (copy_to_user(buffer, link, len))

		len = -EFAULT;

 out:

	return len;

}





int

xfs_readlink_by_handle(

	struct file		*parfilp,
@@ -334,7 +308,7 @@ xfs_readlink_by_handle( 
	error = -xfs_readlink(XFS_I(dentry->d_inode), link);

	if (error)

		goto out_kfree;

	error = do_readlink(hreq->ohandle, olen, link);

	error = readlink_copy(hreq->ohandle, olen, link);

	if (error)

		goto out_kfree;

include/linux/fs.h

+1 −1
Original line number Diff line number Diff line
@@ -2517,7 +2517,7 @@ extern const struct file_operations generic_ro_fops; 


#define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))



extern int vfs_readlink(struct dentry *, char __user *, int, const char *);

extern int readlink_copy(char __user *, int, const char *);

extern int page_readlink(struct dentry *, char __user *, int);

extern void *page_follow_link_light(struct dentry *, struct nameidata *);

extern void page_put_link(struct dentry *, struct nameidata *, void *);