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Message-Id: <200805062118.m46LI7MN004059@devserv.devel.redhat.com>
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 08/18] flag parameters: dup2
This patch adds the new dup3 syscall. It extends the old dup2
syscall by one parameter which is meant to hold a flag value. Support
for the O_CLOEXEC flag is added in this patch.
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 <stdio.h>
#include <time.h>
#include <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_dup3
# ifdef __x86_64__
# define __NR_dup3 292
# elif defined __i386__
# define __NR_dup3 330
# else
# error "need __NR_dup3"
# endif
#endif
int
main (void)
{
int fd = syscall (__NR_dup3, 1, 4, 0);
if (fd == -1)
{
puts ("dup3(0) failed");
return 1;
}
int coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
puts ("dup3(0) set close-on-exec flag");
return 1;
}
close (fd);
fd = syscall (__NR_dup3, 1, 4, O_CLOEXEC);
if (fd == -1)
{
puts ("dup3(O_CLOEXEC) failed");
return 1;
}
coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
puts ("dup3(O_CLOEXEC) set close-on-exec flag");
return 1;
}
close (fd);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/ia32/ia32entry.S | 1 +
arch/x86/kernel/syscall_table_32.S | 1 +
fs/fcntl.c | 15 +++++++++++++--
include/asm-x86/unistd_32.h | 1 +
include/asm-x86/unistd_64.h | 2 ++
include/linux/syscalls.h | 1 +
6 files changed, 19 insertions(+), 2 deletions(-)
Signed-off-by: Ulrich Drepper <drepper@...hat.com>
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 98fd76c..bec604b 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -734,4 +734,5 @@ ia32_sys_call_table:
.quad compat_sys_signalfd4
.quad sys_eventfd2
.quad sys_epoll_create2
+ .quad sys_dup3 /* 330 */
ia32_syscall_end:
diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
index 4d7007c..24a3f1e 100644
--- a/arch/x86/kernel/syscall_table_32.S
+++ b/arch/x86/kernel/syscall_table_32.S
@@ -329,3 +329,4 @@ ENTRY(sys_call_table)
.long sys_signalfd4
.long sys_eventfd2
.long sys_epoll_create2
+ .long sys_dup3 /* 330 */
diff --git a/fs/fcntl.c b/fs/fcntl.c
index bfd7765..49a2284 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -126,13 +126,16 @@ static int dupfd(struct file *file, unsigned int start, int cloexec)
return fd;
}
-asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
+asmlinkage long sys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
{
int err = -EBADF;
struct file * file, *tofree;
struct files_struct * files = current->files;
struct fdtable *fdt;
+ if ((flags & ~O_CLOEXEC) != 0)
+ return -EINVAL;
+
spin_lock(&files->file_lock);
if (!(file = fcheck(oldfd)))
goto out_unlock;
@@ -164,7 +167,10 @@ asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
rcu_assign_pointer(fdt->fd[newfd], file);
FD_SET(newfd, fdt->open_fds);
- FD_CLR(newfd, fdt->close_on_exec);
+ if (flags & O_CLOEXEC)
+ FD_SET(newfd, fdt->close_on_exec);
+ else
+ FD_CLR(newfd, fdt->close_on_exec);
spin_unlock(&files->file_lock);
if (tofree)
@@ -182,6 +188,11 @@ out_fput:
goto out;
}
+asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
+{
+ return sys_dup3(oldfd, newfd, 0);
+}
+
asmlinkage long sys_dup(unsigned int fildes)
{
int ret = -EBADF;
diff --git a/include/asm-x86/unistd_32.h b/include/asm-x86/unistd_32.h
index a37d6b0..a1f6383 100644
--- a/include/asm-x86/unistd_32.h
+++ b/include/asm-x86/unistd_32.h
@@ -335,6 +335,7 @@
#define __NR_signalfd4 327
#define __NR_eventfd2 328
#define __NR_epoll_create2 329
+#define __NR_dup3 330
#ifdef __KERNEL__
diff --git a/include/asm-x86/unistd_64.h b/include/asm-x86/unistd_64.h
index b6315d2..9eb303e 100644
--- a/include/asm-x86/unistd_64.h
+++ b/include/asm-x86/unistd_64.h
@@ -647,6 +647,8 @@ __SYSCALL(__NR_signalfd4, sys_signalfd4)
__SYSCALL(__NR_eventfd2, sys_eventfd2)
#define __NR_epoll_create2 291
__SYSCALL(__NR_epoll_create2, sys_epoll_create2)
+#define __NR_dup3 292
+__SYSCALL(__NR_dup3, sys_dup3)
#ifndef __NO_STUBS
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e33d285..143d5ee 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -305,6 +305,7 @@ asmlinkage long sys_fcntl64(unsigned int fd,
#endif
asmlinkage long sys_dup(unsigned int fildes);
asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd);
+asmlinkage long sys_dup3(unsigned int oldfd, unsigned int newfd, int flags);
asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int on);
asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd,
unsigned long arg);
--
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