flag parameters: epoll_create
This patch adds the new epoll_create2 syscall. It extends the old epoll_create
syscall by one parameter which is meant to hold a flag value. In this
patch the only flag support is EPOLL_CLOEXEC which causes the close-on-exec
flag for the returned file descriptor to be set.
A new name EPOLL_CLOEXEC is introduced which in this implementation must
have the same value as O_CLOEXEC.
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_epoll_create2
# ifdef __x86_64__
# define __NR_epoll_create2 291
# elif defined __i386__
# define __NR_epoll_create2 329
# else
# error "need __NR_epoll_create2"
# endif
#endif
#define EPOLL_CLOEXEC O_CLOEXEC
int
main (void)
{
int fd = syscall (__NR_epoll_create2, 1, 0);
if (fd == -1)
{
puts ("epoll_create2(0) failed");
return 1;
}
int coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
puts ("epoll_create2(0) set close-on-exec flag");
return 1;
}
close (fd);
fd = syscall (__NR_epoll_create2, 1, EPOLL_CLOEXEC);
if (fd == -1)
{
puts ("epoll_create2(EPOLL_CLOEXEC) failed");
return 1;
}
coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
puts ("epoll_create2(EPOLL_CLOEXEC) set close-on-exec flag");
return 1;
}
close (fd);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index cf0eb31..04366f0 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -828,4 +828,5 @@
.quad compat_sys_timerfd_gettime
.quad compat_sys_signalfd4
.quad sys_eventfd2
+ .quad sys_epoll_create2
ia32_syscall_end:
diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
index cf112cb..4d7007c 100644
--- a/arch/x86/kernel/syscall_table_32.S
+++ b/arch/x86/kernel/syscall_table_32.S
@@ -328,3 +328,4 @@
.long sys_timerfd_gettime
.long sys_signalfd4
.long sys_eventfd2
+ .long sys_epoll_create2
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 9392dd9..3fd4014 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1046,11 +1046,14 @@
* RB tree. With the current implementation, the "size" parameter is ignored
* (besides sanity checks).
*/
-asmlinkage long sys_epoll_create(int size)
+asmlinkage long sys_epoll_create2(int size, int flags)
{
int error, fd = -1;
struct eventpoll *ep;
+ if (flags & ~EPOLL_CLOEXEC)
+ return -EINVAL;
+
DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_create(%d)\n",
current, size));
@@ -1068,7 +1071,8 @@
* Creates all the items needed to setup an eventpoll file. That is,
* a file structure and a free file descriptor.
*/
- fd = anon_inode_getfd("[eventpoll]", &eventpoll_fops, ep, 0);
+ fd = anon_inode_getfd("[eventpoll]", &eventpoll_fops, ep,
+ flags & O_CLOEXEC);
if (fd < 0)
ep_free(ep);
@@ -1079,6 +1083,11 @@
return fd;
}
+asmlinkage long sys_epoll_create(int size)
+{
+ return sys_epoll_create2(size, 0);
+}
+
/*
* The following function implements the controller interface for
* the eventpoll file that enables the insertion/removal/change of
diff --git a/include/asm-x86/unistd_32.h b/include/asm-x86/unistd_32.h
index edbd872..a37d6b0 100644
--- a/include/asm-x86/unistd_32.h
+++ b/include/asm-x86/unistd_32.h
@@ -334,6 +334,7 @@
#define __NR_timerfd_gettime 326
#define __NR_signalfd4 327
#define __NR_eventfd2 328
+#define __NR_epoll_create2 329
#ifdef __KERNEL__
diff --git a/include/asm-x86/unistd_64.h b/include/asm-x86/unistd_64.h
index fb059a6..a1a4a5b 100644
--- a/include/asm-x86/unistd_64.h
+++ b/include/asm-x86/unistd_64.h
@@ -645,6 +645,8 @@
__SYSCALL(__NR_signalfd4, sys_signalfd4)
#define __NR_eventfd2 290
__SYSCALL(__NR_eventfd2, sys_eventfd2)
+#define __NR_epoll_create2 291
+__SYSCALL(__NR_epoll_create2, sys_epoll_create2)
#ifndef __NO_STUBS
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h
index cf79853..1cfaa40 100644
--- a/include/linux/eventpoll.h
+++ b/include/linux/eventpoll.h
@@ -14,8 +14,12 @@
#ifndef _LINUX_EVENTPOLL_H
#define _LINUX_EVENTPOLL_H
+/* For O_CLOEXEC */
+#include <linux/fcntl.h>
#include <linux/types.h>
+/* Flags for epoll_create2. */
+#define EPOLL_CLOEXEC O_CLOEXEC
/* Valid opcodes to issue to sys_epoll_ctl() */
#define EPOLL_CTL_ADD 1
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 9ab0992..8595324 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -430,6 +430,7 @@
asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp,
fd_set __user *exp, struct timeval __user *tvp);
asmlinkage long sys_epoll_create(int size);
+asmlinkage long sys_epoll_create2(int size, int flags);
asmlinkage long sys_epoll_ctl(int epfd, int op, int fd,
struct epoll_event __user *event);
asmlinkage long sys_epoll_wait(int epfd, struct epoll_event __user *events,