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Date: Tue, 6 May 2008 17:18:07 -0400
From: Ulrich Drepper <drepper@...hat.com>
To: linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Cc: akpm@...ux-foundation.org, davidel@...ilserver.org,
mtk.manpages@...il.com, torvalds@...ux-foundation.org
Subject: [PATCH 12/18] flag parameters: NONBLOCK in socket and socketpair
This patch introduces support for the SOCK_NONBLOCK flag in socket,
socketpair, and paccept. To do this the internal function sock_attach_fd
gets an additional parameter which it uses to set the appropriate flag for
the file descriptor.
Given that in modern, scalable programs almost all socket connections are
non-blocking and the minimal additional cost for the new functionality
I see no reason not to add this code.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <pthread.h>
#include <stdio.h>
#include <unistd.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#ifndef __NR_paccept
# ifdef __x86_64__
# define __NR_paccept 288
# elif defined __i386__
# define SYS_PACCEPT 18
# define USE_SOCKETCALL 1
# else
# error "need __NR_paccept"
# endif
#endif
#ifdef USE_SOCKETCALL
# define paccept(fd, addr, addrlen, mask, flags) \
({ long args[6] = { \
(long) fd, (long) addr, (long) addrlen, (long) mask, 8, (long) flags }; \
syscall (__NR_socketcall, SYS_PACCEPT, args); })
#else
# define paccept(fd, addr, addrlen, mask, flags) \
syscall (__NR_paccept, fd, addr, addrlen, mask, 8, flags)
#endif
#define PORT 57392
#define SOCK_NONBLOCK O_NONBLOCK
static pthread_barrier_t b;
static void *
tf (void *arg)
{
pthread_barrier_wait (&b);
int s = socket (AF_INET, SOCK_STREAM, 0);
struct sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
sin.sin_port = htons (PORT);
connect (s, (const struct sockaddr *) &sin, sizeof (sin));
close (s);
pthread_barrier_wait (&b);
pthread_barrier_wait (&b);
s = socket (AF_INET, SOCK_STREAM, 0);
sin.sin_port = htons (PORT);
connect (s, (const struct sockaddr *) &sin, sizeof (sin));
close (s);
pthread_barrier_wait (&b);
return NULL;
}
int
main (void)
{
int fd;
fd = socket (PF_INET, SOCK_STREAM, 0);
if (fd == -1)
{
puts ("socket(0) failed");
return 1;
}
int fl = fcntl (fd, F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if (fl & O_NONBLOCK)
{
puts ("socket(0) set non-blocking mode");
return 1;
}
close (fd);
fd = socket (PF_INET, SOCK_STREAM|SOCK_NONBLOCK, 0);
if (fd == -1)
{
puts ("socket(SOCK_NONBLOCK) failed");
return 1;
}
fl = fcntl (fd, F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if ((fl & O_NONBLOCK) == 0)
{
puts ("socket(SOCK_NONBLOCK) does not set non-blocking mode");
return 1;
}
close (fd);
int fds[2];
if (socketpair (PF_UNIX, SOCK_STREAM, 0, fds) == -1)
{
puts ("socketpair(0) failed");
return 1;
}
for (int i = 0; i < 2; ++i)
{
fl = fcntl (fds[i], F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if (fl & O_NONBLOCK)
{
printf ("socketpair(0) set non-blocking mode for fds[%d]\n", i);
return 1;
}
close (fds[i]);
}
if (socketpair (PF_UNIX, SOCK_STREAM|SOCK_NONBLOCK, 0, fds) == -1)
{
puts ("socketpair(SOCK_NONBLOCK) failed");
return 1;
}
for (int i = 0; i < 2; ++i)
{
fl = fcntl (fds[i], F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if ((fl & O_NONBLOCK) == 0)
{
printf ("socketpair(SOCK_NONBLOCK) does not set non-blocking mode for fds[%d]\n", i);
return 1;
}
close (fds[i]);
}
pthread_barrier_init (&b, NULL, 2);
struct sockaddr_in sin;
pthread_t th;
if (pthread_create (&th, NULL, tf, NULL) != 0)
{
puts ("pthread_create failed");
return 1;
}
int s = socket (AF_INET, SOCK_STREAM, 0);
int reuse = 1;
setsockopt (s, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof (reuse));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
sin.sin_port = htons (PORT);
bind (s, (struct sockaddr *) &sin, sizeof (sin));
listen (s, SOMAXCONN);
pthread_barrier_wait (&b);
int s2 = paccept (s, NULL, 0, NULL, 0);
if (s2 < 0)
{
puts ("paccept(0) failed");
return 1;
}
fl = fcntl (s2, F_GETFL);
if (fl & O_NONBLOCK)
{
puts ("paccept(0) set non-blocking mode");
return 1;
}
close (s2);
close (s);
pthread_barrier_wait (&b);
s = socket (AF_INET, SOCK_STREAM, 0);
sin.sin_port = htons (PORT);
setsockopt (s, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof (reuse));
bind (s, (struct sockaddr *) &sin, sizeof (sin));
listen (s, SOMAXCONN);
pthread_barrier_wait (&b);
s2 = paccept (s, NULL, 0, NULL, SOCK_NONBLOCK);
if (s2 < 0)
{
puts ("paccept(SOCK_NONBLOCK) failed");
return 1;
}
fl = fcntl (s2, F_GETFL);
if ((fl & O_NONBLOCK) == 0)
{
puts ("paccept(SOCK_NONBLOCK) does not set non-blocking mode");
return 1;
}
close (s2);
close (s);
pthread_barrier_wait (&b);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/net.h | 3 ++-
net/socket.c | 20 ++++++++++----------
2 files changed, 12 insertions(+), 11 deletions(-)
Signed-off-by: Ulrich Drepper <drepper@...hat.com>
diff --git a/include/linux/net.h b/include/linux/net.h
index b4ad432..1b35fd5 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -20,7 +20,7 @@
#include <linux/wait.h>
#include <linux/socket.h>
-#include <linux/fcntl.h> /* For O_CLOEXEC */
+#include <linux/fcntl.h> /* For O_CLOEXEC and O_NONBLOCK */
#include <asm/socket.h>
struct poll_table_struct;
@@ -102,6 +102,7 @@ enum sock_type {
/* Flags for socket, socketpair, paccept */
#define SOCK_CLOEXEC O_CLOEXEC
+#define SOCK_NONBLOCK O_NONBLOCK
#endif /* ARCH_HAS_SOCKET_TYPES */
diff --git a/net/socket.c b/net/socket.c
index 634ad83..7cb0a5e 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -366,7 +366,7 @@ static int sock_alloc_fd(struct file **filep, int flags)
return fd;
}
-static int sock_attach_fd(struct socket *sock, struct file *file)
+static int sock_attach_fd(struct socket *sock, struct file *file, int flags)
{
struct dentry *dentry;
struct qstr name = { .name = "" };
@@ -388,7 +388,7 @@ static int sock_attach_fd(struct socket *sock, struct file *file)
init_file(file, sock_mnt, dentry, FMODE_READ | FMODE_WRITE,
&socket_file_ops);
SOCK_INODE(sock)->i_fop = &socket_file_ops;
- file->f_flags = O_RDWR;
+ file->f_flags = O_RDWR | (flags & O_NONBLOCK);
file->f_pos = 0;
file->private_data = sock;
@@ -401,7 +401,7 @@ int sock_map_fd(struct socket *sock, int flags)
int fd = sock_alloc_fd(&newfile, flags);
if (likely(fd >= 0)) {
- int err = sock_attach_fd(sock, newfile);
+ int err = sock_attach_fd(sock, newfile, flags);
if (unlikely(err < 0)) {
put_filp(newfile);
@@ -1220,7 +1220,7 @@ asmlinkage long sys_socket(int family, int type, int protocol)
int flags;
flags = type & ~SOCK_TYPE_MASK;
- if (flags & ~SOCK_CLOEXEC)
+ if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
return -EINVAL;
type &= SOCK_TYPE_MASK;
@@ -1228,7 +1228,7 @@ asmlinkage long sys_socket(int family, int type, int protocol)
if (retval < 0)
goto out;
- retval = sock_map_fd(sock, flags & O_CLOEXEC);
+ retval = sock_map_fd(sock, flags & (O_CLOEXEC | O_NONBLOCK));
if (retval < 0)
goto out_release;
@@ -1254,7 +1254,7 @@ asmlinkage long sys_socketpair(int family, int type, int protocol,
int flags;
flags = type & ~SOCK_TYPE_MASK;
- if (flags & ~SOCK_CLOEXEC)
+ if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
return -EINVAL;
type &= SOCK_TYPE_MASK;
@@ -1289,12 +1289,12 @@ asmlinkage long sys_socketpair(int family, int type, int protocol,
goto out_release_both;
}
- err = sock_attach_fd(sock1, newfile1);
+ err = sock_attach_fd(sock1, newfile1, flags & O_NONBLOCK);
if (unlikely(err < 0)) {
goto out_fd2;
}
- err = sock_attach_fd(sock2, newfile2);
+ err = sock_attach_fd(sock2, newfile2, flags & O_NONBLOCK);
if (unlikely(err < 0)) {
fput(newfile1);
goto out_fd1;
@@ -1420,7 +1420,7 @@ long do_accept(int fd, struct sockaddr __user *upeer_sockaddr,
int err, len, newfd, fput_needed;
char address[MAX_SOCK_ADDR];
- if (flags & ~SOCK_CLOEXEC)
+ if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
return -EINVAL;
sock = sockfd_lookup_light(fd, &err, &fput_needed);
@@ -1447,7 +1447,7 @@ long do_accept(int fd, struct sockaddr __user *upeer_sockaddr,
goto out_put;
}
- err = sock_attach_fd(newsock, newfile);
+ err = sock_attach_fd(newsock, newfile, flags & O_NONBLOCK);
if (err < 0)
goto out_fd_simple;
--
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