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net: add __sys_accept4_file() helper

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This is identical to __sys_accept4(), except it takes a struct file
instead of an fd, and it also allows passing in extra file->f_flags
flags. The latter is done to support masking in O_NONBLOCK without
manipulating the original file flags.

No functional changes in this patch.

Cc: netdev@vger.kernel.org
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2019-10-17 14:41:29 -06:00
parent fcb323cc53
commit de2ea4b64b
2 changed files with 44 additions and 24 deletions
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3
include/linux/socket.h
View File

@ -392,6 +392,9 @@ extern int __sys_recvfrom(int fd, void __user *ubuf, size_t size,
extern int __sys_sendto(int fd, void __user *buff, size_t len,
unsigned int flags, struct sockaddr __user *addr,
int addr_len);
extern int __sys_accept4_file(struct file *file, unsigned file_flags,
struct sockaddr __user *upeer_sockaddr,
int __user *upeer_addrlen, int 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);

63
net/socket.c
View File

@ -1690,24 +1690,13 @@ SYSCALL_DEFINE2(listen, int, fd, int, backlog)
return __sys_listen(fd, backlog);
}
/*
* For accept, we attempt to create a new socket, set up the link
* with the client, wake up the client, then return the new
* connected fd. We collect the address of the connector in kernel
* space and move it to user at the very end. This is unclean because
* we open the socket then return an error.
*
* 1003.1g adds the ability to recvmsg() to query connection pending
* status to recvmsg. We need to add that support in a way thats
* clean when we restructure accept also.
*/
int __sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,
int __sys_accept4_file(struct file *file, unsigned file_flags,
struct sockaddr __user *upeer_sockaddr,
int __user *upeer_addrlen, int flags)
{
struct socket *sock, *newsock;
struct file *newfile;
int err, len, newfd, fput_needed;
int err, len, newfd;
struct sockaddr_storage address;
if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
@ -1716,14 +1705,14 @@ int __sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,
if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
sock = sockfd_lookup_light(fd, &err, &fput_needed);
sock = sock_from_file(file, &err);
if (!sock)
goto out;
err = -ENFILE;
newsock = sock_alloc();
if (!newsock)
goto out_put;
goto out;
newsock->type = sock->type;
newsock->ops = sock->ops;
@ -1738,20 +1727,21 @@ int __sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,
if (unlikely(newfd < 0)) {
err = newfd;
sock_release(newsock);
goto out_put;
goto out;
}
newfile = sock_alloc_file(newsock, flags, sock->sk->sk_prot_creator->name);
if (IS_ERR(newfile)) {
err = PTR_ERR(newfile);
put_unused_fd(newfd);
goto out_put;
goto out;
}
err = security_socket_accept(sock, newsock);
if (err)
goto out_fd;
err = sock->ops->accept(sock, newsock, sock->file->f_flags, false);
err = sock->ops->accept(sock, newsock, sock->file->f_flags | file_flags,
false);
if (err < 0)
goto out_fd;
@ -1772,15 +1762,42 @@ int __sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,
fd_install(newfd, newfile);
err = newfd;
out_put:
fput_light(sock->file, fput_needed);
out:
return err;
out_fd:
fput(newfile);
put_unused_fd(newfd);
goto out_put;
goto out;
}
/*
* For accept, we attempt to create a new socket, set up the link
* with the client, wake up the client, then return the new
* connected fd. We collect the address of the connector in kernel
* space and move it to user at the very end. This is unclean because
* we open the socket then return an error.
*
* 1003.1g adds the ability to recvmsg() to query connection pending
* status to recvmsg. We need to add that support in a way thats
* clean when we restructure accept also.
*/
int __sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,
int __user *upeer_addrlen, int flags)
{
int ret = -EBADF;
struct fd f;
f = fdget(fd);
if (f.file) {
ret = __sys_accept4_file(f.file, 0, upeer_sockaddr,
upeer_addrlen, flags);
if (f.flags)
fput(f.file);
}
return ret;
}
SYSCALL_DEFINE4(accept4, int, fd, struct sockaddr __user *, upeer_sockaddr,