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>
This commit is contained in:
Ulrich Drepper 2008-07-23 21:29:27 -07:00 committed by Linus Torvalds
parent 11fcb6c146
commit a0998b50c3
7 changed files with 21 additions and 2 deletions

View File

@ -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:

View File

@ -328,3 +328,4 @@ ENTRY(sys_call_table)
.long sys_timerfd_gettime
.long sys_signalfd4
.long sys_eventfd2
.long sys_epoll_create2

View File

@ -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

View File

@ -334,6 +334,7 @@
#define __NR_timerfd_gettime 326
#define __NR_signalfd4 327
#define __NR_eventfd2 328
#define __NR_epoll_create2 329
#ifdef __KERNEL__

View File

@ -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

View File

@ -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

View File

@ -430,6 +430,7 @@ asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
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,