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net: add __sys_socket_file()

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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: Jens Axboe <axboe@kernel.dk>
Acked-by: David S. Miller <davem@davemloft.net>
Link: https://lore.kernel.org/r/20220412202240.234207-2-axboe@kernel.dk
This commit is contained in:
Jens Axboe 2022-04-12 14:22:39 -06:00
parent 0200ce6a57
commit da214a475f
2 changed files with 44 additions and 11 deletions
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1
include/linux/socket.h
View File

@ -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);

54
net/socket.c
View File

@ -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;
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;
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;
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));
}