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Message-Id: <200804241618.m3OGI9kd013025@devserv.devel.redhat.com>
Date: Thu, 24 Apr 2008 12:18:09 -0400
From: Ulrich Drepper <drepper@...hat.com>
To: linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Cc: akpm@...ux-foundation.org, torvalds@...ux-foundation.org
Subject: [PATCH] alternative^2 to sys_indirect: socket, socketpair
Here is a patch with just the socket and socketpair changes which uses
a new SOCK_CLOEXEC flag. I started the flags at the high end (ignoring
the sign bit) to avoid collisions. accept() is not changed in this
patch.
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#define SOCK_CLOEXEC 0x40000000
#define PORT 57392
int
main (void)
{
int status = 0;
int s;
int sp[2];
s = socket (PF_UNIX, SOCK_STREAM, 0);
if (s < 0)
{
puts ("socket failed");
status = 1;
}
else
{
int fl = fcntl(s, F_GETFD);
if ((fl & FD_CLOEXEC) != 0)
{
puts ("socket did set CLOEXEC");
status = 1;
}
close (s);
}
s = socket (PF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
if (s < 0)
{
puts ("socket(SOCK_CLOEXEC) failed");
status = 1;
}
else
{
int fl = fcntl(s, F_GETFD);
if ((fl & FD_CLOEXEC) == 0)
{
puts ("socket(SOCK_CLOEXEC) did not set CLOEXEC");
status = 1;
}
close (s);
}
if (socketpair (PF_UNIX, SOCK_STREAM, 0, sp) < 0)
{
puts ("socketpair failed");
status = 1;
}
else
{
int fl1 = fcntl(sp[0], F_GETFD);
int fl2 = fcntl(sp[1], F_GETFD);
if ((fl1 & FD_CLOEXEC) != 0 || (fl2 & FD_CLOEXEC) != 0)
{
puts ("socketpair did set CLOEXEC");
status = 1;
}
close (sp[0]);
close (sp[1]);
}
if (socketpair (PF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0, sp) < 0)
{
puts ("socketpair(SOCK_CLOEXEC) failed");
status = 1;
}
else
{
int fl1 = fcntl(sp[0], F_GETFD);
int fl2 = fcntl(sp[1], F_GETFD);
if ((fl1 & FD_CLOEXEC) == 0 || (fl2 & FD_CLOEXEC) == 0)
{
puts ("socketpair(SOCK_CLOEXEC) did not set CLOEXEC");
status = 1;
}
close (sp[0]);
close (sp[1]);
}
return status;
}
include/linux/net.h | 3 +++
net/socket.c | 35 +++++++++++++++++++++++++++--------
2 files changed, 30 insertions(+), 8 deletions(-)
Signed-off-by: Ulrich Drepper <drepper@...hat.com>
diff --git a/include/linux/net.h b/include/linux/net.h
index 71f7dd5..f5dddd8 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -91,6 +91,9 @@ enum sock_type {
SOCK_SEQPACKET = 5,
SOCK_DCCP = 6,
SOCK_PACKET = 10,
+
+ /* Flag values, ORed to the types above. */
+ SOCK_CLOEXEC = 0x40000000
};
#define SOCK_MAX (SOCK_PACKET + 1)
diff --git a/net/socket.c b/net/socket.c
index 9b5c917..e144f8a 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -348,11 +348,11 @@ static struct dentry_operations sockfs_dentry_operations = {
* but we take care of internal coherence yet.
*/
-static int sock_alloc_fd(struct file **filep)
+static int sock_alloc_fd(struct file **filep, int flags)
{
int fd;
- fd = get_unused_fd();
+ fd = get_unused_fd_flags(flags);
if (likely(fd >= 0)) {
struct file *file = get_empty_filp();
@@ -395,10 +395,10 @@ static int sock_attach_fd(struct socket *sock, struct file *file)
return 0;
}
-int sock_map_fd(struct socket *sock)
+static int sock_map_fd_flags(struct socket *sock, int flags)
{
struct file *newfile;
- int fd = sock_alloc_fd(&newfile);
+ int fd = sock_alloc_fd(&newfile, flags);
if (likely(fd >= 0)) {
int err = sock_attach_fd(sock, newfile);
@@ -413,6 +413,11 @@ int sock_map_fd(struct socket *sock)
return fd;
}
+int sock_map_fd(struct socket *sock)
+{
+ return sock_map_fd_flags(sock, 0);
+}
+
static struct socket *sock_from_file(struct file *file, int *err)
{
if (file->f_op == &socket_file_ops)
@@ -1217,12 +1222,19 @@ asmlinkage long sys_socket(int family, int type, int protocol)
{
int retval;
struct socket *sock;
+ int fflags = 0;
+
+ /* Extract the close-on-exec flag. */
+ if ((type & SOCK_CLOEXEC) != 0) {
+ fflags = O_CLOEXEC;
+ type &= ~SOCK_CLOEXEC;
+ }
retval = sock_create(family, type, protocol, &sock);
if (retval < 0)
goto out;
- retval = sock_map_fd(sock);
+ retval = sock_map_fd_flags(sock, fflags);
if (retval < 0)
goto out_release;
@@ -1245,6 +1257,13 @@ asmlinkage long sys_socketpair(int family, int type, int protocol,
struct socket *sock1, *sock2;
int fd1, fd2, err;
struct file *newfile1, *newfile2;
+ int fflags = 0;
+
+ /* Extract the close-on-exec flag. */
+ if ((type & SOCK_CLOEXEC) != 0) {
+ fflags = O_CLOEXEC;
+ type &= ~SOCK_CLOEXEC;
+ }
/*
* Obtain the first socket and check if the underlying protocol
@@ -1263,13 +1282,13 @@ asmlinkage long sys_socketpair(int family, int type, int protocol,
if (err < 0)
goto out_release_both;
- fd1 = sock_alloc_fd(&newfile1);
+ fd1 = sock_alloc_fd(&newfile1, fflags);
if (unlikely(fd1 < 0)) {
err = fd1;
goto out_release_both;
}
- fd2 = sock_alloc_fd(&newfile2);
+ fd2 = sock_alloc_fd(&newfile2, fflags);
if (unlikely(fd2 < 0)) {
err = fd2;
put_filp(newfile1);
@@ -1425,7 +1444,7 @@ asmlinkage long sys_accept(int fd, struct sockaddr __user *upeer_sockaddr,
*/
__module_get(newsock->ops->owner);
- newfd = sock_alloc_fd(&newfile);
+ newfd = sock_alloc_fd(&newfile, 0);
if (unlikely(newfd < 0)) {
err = newfd;
sock_release(newsock);
--
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