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/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 021d71b..c308128 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -826,4 +826,5 @@
.quad sys32_fallocate
.quad compat_sys_timerfd_settime /* 325 */
.quad compat_sys_timerfd_gettime
+ .quad compat_sys_signalfd4
ia32_syscall_end:
diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
index adff556..c12a36c 100644
--- a/arch/x86/kernel/syscall_table_32.S
+++ b/arch/x86/kernel/syscall_table_32.S
@@ -326,3 +326,4 @@
.long sys_fallocate
.long sys_timerfd_settime /* 325 */
.long sys_timerfd_gettime
+ .long sys_signalfd4
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
diff --git a/fs/signalfd.c b/fs/signalfd.c
index ddb328b..c8609fa 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -205,11 +205,15 @@
.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 @@
* 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 @@
return ufd;
}
+
+asmlinkage long sys_signalfd(int ufd, sigset_t __user *user_mask,
+ size_t sizemask)
+{
+ return sys_signalfd4(ufd, user_mask, sizemask, 0);
+}
diff --git a/include/asm-x86/unistd_32.h b/include/asm-x86/unistd_32.h
index 8317d94..c310371 100644
--- a/include/asm-x86/unistd_32.h
+++ b/include/asm-x86/unistd_32.h
@@ -332,6 +332,7 @@
#define __NR_fallocate 324
#define __NR_timerfd_settime 325
#define __NR_timerfd_gettime 326
+#define __NR_signalfd4 327
#ifdef __KERNEL__
diff --git a/include/asm-x86/unistd_64.h b/include/asm-x86/unistd_64.h
index e323994..e0a9b45 100644
--- a/include/asm-x86/unistd_64.h
+++ b/include/asm-x86/unistd_64.h
@@ -641,6 +641,8 @@
__SYSCALL(__NR_timerfd_gettime, sys_timerfd_gettime)
#define __NR_paccept 288
__SYSCALL(__NR_paccept, sys_paccept)
+#define __NR_signalfd4 289
+__SYSCALL(__NR_signalfd4, sys_signalfd4)
#ifndef __NO_STUBS
diff --git a/include/linux/signalfd.h b/include/linux/signalfd.h
index ea037f2..8b3f7b7 100644
--- a/include/linux/signalfd.h
+++ b/include/linux/signalfd.h
@@ -8,6 +8,11 @@
#ifndef _LINUX_SIGNALFD_H
#define _LINUX_SIGNALFD_H
+/* For O_CLOEXEC */
+#include <linux/fcntl.h>
+
+/* Flags for signalfd4. */
+#define SFD_CLOEXEC O_CLOEXEC
struct signalfd_siginfo {
__u32 ssi_signo;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 2a2a40a..1c27077 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -610,6 +610,7 @@
size_t len);
asmlinkage long sys_getcpu(unsigned __user *cpu, unsigned __user *node, struct getcpu_cache __user *cache);
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);
asmlinkage long sys_timerfd_create(int clockid, int flags);
asmlinkage long sys_timerfd_settime(int ufd, int flags,
const struct itimerspec __user *utmr,
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 2f0b8a2..8627c89 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -156,6 +156,7 @@
/* New file descriptors */
cond_syscall(sys_signalfd);
+cond_syscall(sys_signalfd4);
cond_syscall(compat_sys_signalfd);
cond_syscall(sys_timerfd_create);
cond_syscall(sys_timerfd_settime);