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Commit f52e0c11 authored by Al Viro's avatar Al Viro
Browse files

New AT_... flag: AT_EMPTY_PATH 



For name_to_handle_at(2) we'll want both ...at()-style syscall that
would be usable for non-directory descriptors (with empty relative
pathname).  Introduce new flag (AT_EMPTY_PATH) to deal with that and
corresponding LOOKUP_EMPTY; teach user_path_at() and path_init() to
deal with the latter.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 5fe0c237

fs/namei.c

+19 −10
Original line number Diff line number Diff line
@@ -136,7 +136,7 @@ static int do_getname(const char __user *filename, char *page) 
	return retval;

}



char * getname(const char __user * filename)

static char *getname_flags(const char __user * filename, int flags)

{

	char *tmp, *result;
@@ -147,14 +147,21 @@ char * getname(const char __user * filename) 


		result = tmp;

		if (retval < 0) {

			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)

{
@@ -1544,6 +1551,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, 


		dentry = file->f_path.dentry;



		if (*name) {

			retval = -ENOTDIR;

			if (!S_ISDIR(dentry->d_inode->i_mode))

				goto fput_fail;
@@ -1551,6 +1559,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, 
			retval = file_permission(file, MAY_EXEC);

			if (retval)

				goto fput_fail;

		}



		nd->path = file->f_path;

		if (flags & LOOKUP_RCU) {
@@ -1759,7 +1768,7 @@ int user_path_at(int dfd, const char __user *name, unsigned flags, 
		 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)) {

include/linux/fcntl.h

+1 −0
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ 
                                           unlinking file.  */

#define AT_SYMLINK_FOLLOW	0x400   /* Follow symbolic links.  */

#define AT_NO_AUTOMOUNT		0x800	/* Suppress terminal automount traversal */

#define AT_EMPTY_PATH		0x1000	/* Allow empty relative pathname */



#ifdef __KERNEL__

include/linux/namei.h

+1 −0
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND}; 


#define LOOKUP_JUMPED		0x1000

#define LOOKUP_ROOT		0x2000

#define LOOKUP_EMPTY		0x4000



extern int user_path_at(int, const char __user *, unsigned, struct path *);