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Commit 9deb27ba authored by Ulrich Drepper's avatar Ulrich Drepper Committed by Linus Torvalds
Browse files

flag parameters: signalfd 



This patch adds the new signalfd4 syscall.  It extends the old signalfd
syscall by one parameter which is meant to hold a flag value.  In this
patch the only flag support is SFD_CLOEXEC which causes the close-on-exec
flag for the returned file descriptor to be set.

A new name SFD_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 <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>

#ifndef __NR_signalfd4
# ifdef __x86_64__
#  define __NR_signalfd4 289
# elif defined __i386__
#  define __NR_signalfd4 327
# else
#  error "need __NR_signalfd4"
# endif
#endif

#define SFD_CLOEXEC O_CLOEXEC

int
main (void)
{
  sigset_t ss;
  sigemptyset (&ss);
  sigaddset (&ss, SIGUSR1);
  int fd = syscall (__NR_signalfd4, -1, &ss, 8, 0);
  if (fd == -1)
    {
      puts ("signalfd4(0) failed");
      return 1;
    }
  int coe = fcntl (fd, F_GETFD);
  if (coe == -1)
    {
      puts ("fcntl failed");
      return 1;
    }
  if (coe & FD_CLOEXEC)
    {
      puts ("signalfd4(0) set close-on-exec flag");
      return 1;
    }
  close (fd);

  fd = syscall (__NR_signalfd4, -1, &ss, 8, SFD_CLOEXEC);
  if (fd == -1)
    {
      puts ("signalfd4(SFD_CLOEXEC) failed");
      return 1;
    }
  coe = fcntl (fd, F_GETFD);
  if (coe == -1)
    {
      puts ("fcntl failed");
      return 1;
    }
  if ((coe & FD_CLOEXEC) == 0)
    {
      puts ("signalfd4(SFD_CLOEXEC) does not set close-on-exec flag");
      return 1;
    }
  close (fd);

  puts ("OK");

  return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[akpm@linux-foundation.org: add sys_ni stub]
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 7d9dbca3

arch/x86/ia32/ia32entry.S

+1 −0
Original line number Diff line number Diff line
@@ -826,4 +826,5 @@ ia32_sys_call_table: 
	.quad sys32_fallocate

	.quad compat_sys_timerfd_settime	/* 325 */

	.quad compat_sys_timerfd_gettime

	.quad compat_sys_signalfd4

ia32_syscall_end:

arch/x86/kernel/syscall_table_32.S

+1 −0
Original line number Diff line number Diff line
@@ -326,3 +326,4 @@ ENTRY(sys_call_table) 
	.long sys_fallocate

	.long sys_timerfd_settime	/* 325 */

	.long sys_timerfd_gettime

	.long sys_signalfd4

fs/compat.c

+10 −4
Original line number Diff line number Diff line
@@ -2131,9 +2131,9 @@ asmlinkage long compat_sys_epoll_pwait(int epfd, 


#ifdef CONFIG_SIGNALFD



asmlinkage long compat_sys_signalfd(int ufd,

asmlinkage long compat_sys_signalfd4(int ufd,

				     const compat_sigset_t __user *sigmask,

				    compat_size_t sigsetsize)

				     compat_size_t sigsetsize, int flags)

{

	compat_sigset_t ss32;

	sigset_t tmp;
@@ -2148,9 +2148,15 @@ asmlinkage long compat_sys_signalfd(int ufd, 
	if (copy_to_user(ksigmask, &tmp, sizeof(sigset_t)))

		return -EFAULT;



	return sys_signalfd(ufd, ksigmask, sizeof(sigset_t));

	return sys_signalfd4(ufd, ksigmask, sizeof(sigset_t), flags);

}



asmlinkage long compat_sys_signalfd(int ufd,

				    const compat_sigset_t __user *sigmask,

				    compat_size_t sigsetsize)

{

	return compat_sys_signalfd4(ufd, sigmask, sigsetsize, 0);

}

#endif /* CONFIG_SIGNALFD */



#ifdef CONFIG_TIMERFD

fs/signalfd.c

+12 −2
Original line number Diff line number Diff line
@@ -205,11 +205,15 @@ static const struct file_operations signalfd_fops = { 
	.read		= signalfd_read,

};



asmlinkage long sys_signalfd(int ufd, sigset_t __user *user_mask, size_t sizemask)

asmlinkage long sys_signalfd4(int ufd, sigset_t __user *user_mask,

			      size_t sizemask, int flags)

{

	sigset_t sigmask;

	struct signalfd_ctx *ctx;



	if (flags & ~SFD_CLOEXEC)

		return -EINVAL;



	if (sizemask != sizeof(sigset_t) ||

	    copy_from_user(&sigmask, user_mask, sizeof(sigmask)))

		return -EINVAL;
@@ -228,7 +232,7 @@ asmlinkage long sys_signalfd(int ufd, sigset_t __user *user_mask, size_t sizemas 
		 * anon_inode_getfd() will install the fd.

		 */

		ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx,

				       0);

				       flags & O_CLOEXEC);

		if (ufd < 0)

			kfree(ctx);

	} else {
@@ -250,3 +254,9 @@ asmlinkage long sys_signalfd(int ufd, sigset_t __user *user_mask, size_t sizemas 


	return ufd;

}



asmlinkage long sys_signalfd(int ufd, sigset_t __user *user_mask,

			     size_t sizemask)

{

	return sys_signalfd4(ufd, user_mask, sizemask, 0);

}

include/asm-x86/unistd_32.h

+1 −0
Original line number Diff line number Diff line
@@ -332,6 +332,7 @@ 
#define __NR_fallocate		324

#define __NR_timerfd_settime	325

#define __NR_timerfd_gettime	326

#define __NR_signalfd4		327



#ifdef __KERNEL__