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Commit a0998b50 authored by Ulrich Drepper's avatar Ulrich Drepper Committed by Linus Torvalds
Browse files

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: default avatarUlrich Drepper <drepper@redhat.com>
Acked-by: default avatarDavide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 11fcb6c1

arch/x86/ia32/ia32entry.S

+1 −0
Original line number Diff line number Diff line
@@ -828,4 +828,5 @@ ia32_sys_call_table: 
	.quad compat_sys_timerfd_gettime

	.quad compat_sys_signalfd4

	.quad sys_eventfd2

	.quad sys_epoll_create2

ia32_syscall_end:

arch/x86/kernel/syscall_table_32.S

+1 −0
Original line number Diff line number Diff line
@@ -328,3 +328,4 @@ ENTRY(sys_call_table) 
	.long sys_timerfd_gettime

	.long sys_signalfd4

	.long sys_eventfd2

	.long sys_epoll_create2

fs/eventpoll.c

+11 −2
Original line number Diff line number Diff line
@@ -1046,11 +1046,14 @@ retry: 
 * 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 @@ asmlinkage long sys_epoll_create(int size) 
	 * 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 @@ error_return: 
	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

include/asm-x86/unistd_32.h

+1 −0
Original line number Diff line number Diff line
@@ -334,6 +334,7 @@ 
#define __NR_timerfd_gettime	326

#define __NR_signalfd4		327

#define __NR_eventfd2		328

#define __NR_epoll_create2	329



#ifdef __KERNEL__

include/asm-x86/unistd_64.h

+2 −0
Original line number Diff line number Diff line
@@ -645,6 +645,8 @@ __SYSCALL(__NR_paccept, sys_paccept) 
__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