Commit da214a47 authored by Jens Axboe's avatar Jens Axboe
Browse files

net: add __sys_socket_file() 



This works like __sys_socket(), except instead of allocating and
returning a socket fd, it just returns the file associated with the
socket. No fd is installed into the process file table.

This is similar to do_accept(), and allows io_uring to use this without
instantiating a file descriptor in the process file table.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Link: https://lore.kernel.org/r/20220412202240.234207-2-axboe@kernel.dk
parent 0200ce6a

include/linux/socket.h

+1 −0
Original line number Diff line number Diff line
@@ -434,6 +434,7 @@ extern struct file *do_accept(struct file *file, unsigned file_flags, 
extern int __sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,

			 int __user *upeer_addrlen, int flags);

extern int __sys_socket(int family, int type, int protocol);

extern struct file *__sys_socket_file(int family, int type, int protocol);

extern int __sys_bind(int fd, struct sockaddr __user *umyaddr, int addrlen);

extern int __sys_connect_file(struct file *file, struct sockaddr_storage *addr,

			      int addrlen, int file_flags);

net/socket.c

+42 −10
Original line number Diff line number Diff line
@@ -504,7 +504,7 @@ static int sock_map_fd(struct socket *sock, int flags) 
struct socket *sock_from_file(struct file *file)

{

	if (file->f_op == &socket_file_ops)

		return file->private_data;	/* set in sock_map_fd */

		return file->private_data;	/* set in sock_alloc_file */



	return NULL;

}
@@ -1538,11 +1538,10 @@ int sock_create_kern(struct net *net, int family, int type, int protocol, struct 
}

EXPORT_SYMBOL(sock_create_kern);



int __sys_socket(int family, int type, int protocol)

static struct socket *__sys_socket_create(int family, int type, int protocol)

{

	int retval;

	struct socket *sock;

	int flags;

	int retval;



	/* Check the SOCK_* constants for consistency.  */

	BUILD_BUG_ON(SOCK_CLOEXEC != O_CLOEXEC);
@@ -1550,17 +1549,50 @@ int __sys_socket(int family, int type, int protocol) 
	BUILD_BUG_ON(SOCK_CLOEXEC & SOCK_TYPE_MASK);

	BUILD_BUG_ON(SOCK_NONBLOCK & SOCK_TYPE_MASK);



	flags = type & ~SOCK_TYPE_MASK;

	if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))

		return -EINVAL;

	if ((type & ~SOCK_TYPE_MASK) & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))

		return ERR_PTR(-EINVAL);

	type &= SOCK_TYPE_MASK;



	retval = sock_create(family, type, protocol, &sock);

	if (retval < 0)

		return ERR_PTR(retval);



	return sock;

}



struct file *__sys_socket_file(int family, int type, int protocol)

{

	struct socket *sock;

	struct file *file;

	int flags;



	sock = __sys_socket_create(family, type, protocol);

	if (IS_ERR(sock))

		return ERR_CAST(sock);



	flags = type & ~SOCK_TYPE_MASK;

	if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))

		flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;



	retval = sock_create(family, type, protocol, &sock);

	if (retval < 0)

		return retval;

	file = sock_alloc_file(sock, flags, NULL);

	if (IS_ERR(file))

		sock_release(sock);



	return file;

}



int __sys_socket(int family, int type, int protocol)

{

	struct socket *sock;

	int flags;



	sock = __sys_socket_create(family, type, protocol);

	if (IS_ERR(sock))

		return PTR_ERR(sock);



	flags = type & ~SOCK_TYPE_MASK;

	if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))

		flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;



	return sock_map_fd(sock, flags & (O_CLOEXEC | O_NONBLOCK));

}