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: 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/fs/compat.c b/fs/compat.c
index b466042..106eba2 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -2131,9 +2131,9 @@
#ifdef CONFIG_SIGNALFD
-asmlinkage long compat_sys_signalfd(int ufd,
- const compat_sigset_t __user *sigmask,
- compat_size_t sigsetsize)
+asmlinkage long compat_sys_signalfd4(int ufd,
+ const compat_sigset_t __user *sigmask,
+ compat_size_t sigsetsize, int flags)
{
compat_sigset_t ss32;
sigset_t tmp;
@@ -2148,9 +2148,15 @@
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
