linux-kernel - [PATCH 13/18] flag parameters: NONBLOCK in signalfd

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:	Tue, 6 May 2008 17:18:07 -0400
From:	Ulrich Drepper <drepper@...hat.com>
To:	linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Cc:	akpm@...ux-foundation.org, davidel@...ilserver.org,
	mtk.manpages@...il.com, torvalds@...ux-foundation.org
Subject: [PATCH 13/18] flag parameters: NONBLOCK in signalfd

This patch adds support for the SFD_NONBLOCK flag to signalfd4.  The
additional changes needed are minimal.

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_NONBLOCK O_NONBLOCK

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 fl = fcntl (fd, F_GETFL);
  if (fl == -1)
    {
      puts ("fcntl failed");
      return 1;
    }
  if (fl & O_NONBLOCK)
    {
      puts ("signalfd4(0) set non-blocking mode");
      return 1;
    }
  close (fd);

  fd = syscall (__NR_signalfd4, -1, &ss, 8, SFD_NONBLOCK);
  if (fd == -1)
    {
      puts ("signalfd4(SFD_NONBLOCK) failed");
      return 1;
    }
  fl = fcntl (fd, F_GETFL);
  if (fl == -1)
    {
      puts ("fcntl failed");
      return 1;
    }
  if ((fl & O_NONBLOCK) == 0)
    {
      puts ("signalfd4(SFD_NONBLOCK) does not set non-blocking mode");
      return 1;
    }
  close (fd);

  puts ("OK");

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

 fs/signalfd.c            |    4 ++--
 include/linux/signalfd.h |    3 ++-
 2 files changed, 4 insertions(+), 3 deletions(-)


Signed-off-by: Ulrich Drepper <drepper@...hat.com>

diff --git a/fs/signalfd.c b/fs/signalfd.c
index c8609fa..5441a4b 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -211,7 +211,7 @@ asmlinkage long sys_signalfd4(int ufd, sigset_t __user *user_mask,
 	sigset_t sigmask;
 	struct signalfd_ctx *ctx;
 
-	if (flags & ~SFD_CLOEXEC)
+	if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK))
 		return -EINVAL;
 
 	if (sizemask != sizeof(sigset_t) ||
@@ -232,7 +232,7 @@ asmlinkage long sys_signalfd4(int ufd, sigset_t __user *user_mask,
 		 * anon_inode_getfd() will install the fd.
 		 */
 		ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx,
-				       flags & O_CLOEXEC);
+				       flags & (O_CLOEXEC | O_NONBLOCK));
 		if (ufd < 0)
 			kfree(ctx);
 	} else {
diff --git a/include/linux/signalfd.h b/include/linux/signalfd.h
index 8b3f7b7..bef0c46 100644
--- a/include/linux/signalfd.h
+++ b/include/linux/signalfd.h
@@ -8,11 +8,12 @@
 #ifndef _LINUX_SIGNALFD_H
 #define _LINUX_SIGNALFD_H
 
-/* For O_CLOEXEC */
+/* For O_CLOEXEC and O_NONBLOCK */
 #include <linux/fcntl.h>
 
 /* Flags for signalfd4.  */
 #define SFD_CLOEXEC O_CLOEXEC
+#define SFD_NONBLOCK O_NONBLOCK
 
 struct signalfd_siginfo {
 	__u32 ssi_signo;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/