From: Ulrich Drepper <drepper@xxxxxxxxxx>
This patch adds the new eventfd2 syscall. It extends the old eventfd
syscall by one parameter which is meant to hold a flag value. In this
patch the only flag support is EFD_CLOEXEC which causes the close-on-exec
flag for the returned file descriptor to be set.
A new name EFD_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 <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_eventfd2
# ifdef __x86_64__
# define __NR_eventfd2 290
# elif defined __i386__
# define __NR_eventfd2 328
# else
# error "need __NR_eventfd2"
# endif
#endif
#define EFD_CLOEXEC O_CLOEXEC
int
main (void)
{
int fd = syscall (__NR_eventfd2, 1, 0);
if (fd == -1)
{
puts ("eventfd2(0) failed");
return 1;
}
int coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
puts ("eventfd2(0) sets close-on-exec flag");
return 1;
}
close (fd);
fd = syscall (__NR_eventfd2, 1, EFD_CLOEXEC);
if (fd == -1)
{
puts ("eventfd2(EFD_CLOEXEC) failed");
return 1;
}
coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
puts ("eventfd2(EFD_CLOEXEC) does not set close-on-exec flag");
return 1;
}
close (fd);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[akpm@xxxxxxxxxxxxxxxxxxxx: add sys_ni stub]
Signed-off-by: Ulrich Drepper <drepper@xxxxxxxxxx>
Acked-by: Davide Libenzi <davidel@xxxxxxxxxxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxxxxxxx>
Cc: <linux-arch@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/ia32/ia32entry.S | 1 +
arch/x86/kernel/syscall_table_32.S | 1 +
fs/eventfd.c | 13 +++++++++++--
include/asm-x86/unistd_32.h | 1 +
include/asm-x86/unistd_64.h | 2 ++
include/linux/eventfd.h | 6 ++++++
include/linux/syscalls.h | 1 +
kernel/sys_ni.c | 1 +
8 files changed, 24 insertions(+), 2 deletions(-)
diff -puN arch/x86/ia32/ia32entry.S~flag-parameters-eventfd arch/x86/ia32/ia32entry.S
--- a/arch/x86/ia32/ia32entry.S~flag-parameters-eventfd
+++ a/arch/x86/ia32/ia32entry.S
@@ -744,4 +744,5 @@ ia32_sys_call_table:
.quad compat_sys_timerfd_settime /* 325 */
.quad compat_sys_timerfd_gettime
.quad compat_sys_signalfd4
+ .quad sys_eventfd2
ia32_syscall_end:
diff -puN arch/x86/kernel/syscall_table_32.S~flag-parameters-eventfd arch/x86/kernel/syscall_table_32.S
--- a/arch/x86/kernel/syscall_table_32.S~flag-parameters-eventfd
+++ a/arch/x86/kernel/syscall_table_32.S
@@ -327,3 +327,4 @@ ENTRY(sys_call_table)
.long sys_timerfd_settime /* 325 */
.long sys_timerfd_gettime
.long sys_signalfd4
+ .long sys_eventfd2
diff -puN fs/eventfd.c~flag-parameters-eventfd fs/eventfd.c
--- a/fs/eventfd.c~flag-parameters-eventfd
+++ a/fs/eventfd.c
@@ -198,11 +198,14 @@ struct file *eventfd_fget(int fd)
return file;
}
-asmlinkage long sys_eventfd(unsigned int count)
+asmlinkage long sys_eventfd2(unsigned int count, int flags)
{
int fd;
struct eventfd_ctx *ctx;
+ if (flags & ~EFD_CLOEXEC)
+ return -EINVAL;
+
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
@@ -214,9 +217,15 @@ asmlinkage long sys_eventfd(unsigned int
* When we call this, the initialization must be complete, since
* anon_inode_getfd() will install the fd.
*/
- fd = anon_inode_getfd("[eventfd]", &eventfd_fops, ctx, 0);
+ fd = anon_inode_getfd("[eventfd]", &eventfd_fops, ctx,
+ flags & O_CLOEXEC);
if (fd < 0)
kfree(ctx);
return fd;
}
+asmlinkage long sys_eventfd(unsigned int count)
+{
+ return sys_eventfd2(count, 0);
+}
+
diff -puN include/asm-x86/unistd_32.h~flag-parameters-eventfd include/asm-x86/unistd_32.h
--- a/include/asm-x86/unistd_32.h~flag-parameters-eventfd
+++ a/include/asm-x86/unistd_32.h
@@ -333,6 +333,7 @@
#define __NR_timerfd_settime 325
#define __NR_timerfd_gettime 326
#define __NR_signalfd4 327
+#define __NR_eventfd2 328
#ifdef __KERNEL__
diff -puN include/asm-x86/unistd_64.h~flag-parameters-eventfd include/asm-x86/unistd_64.h
--- a/include/asm-x86/unistd_64.h~flag-parameters-eventfd
+++ a/include/asm-x86/unistd_64.h
@@ -643,6 +643,8 @@ __SYSCALL(__NR_timerfd_gettime, sys_time
__SYSCALL(__NR_paccept, sys_paccept)
#define __NR_signalfd4 289
__SYSCALL(__NR_signalfd4, sys_signalfd4)
+#define __NR_eventfd2 290
+__SYSCALL(__NR_eventfd2, sys_eventfd2)
#ifndef __NO_STUBS
diff -puN include/linux/eventfd.h~flag-parameters-eventfd include/linux/eventfd.h
--- a/include/linux/eventfd.h~flag-parameters-eventfd
+++ a/include/linux/eventfd.h
@@ -10,6 +10,12 @@
#ifdef CONFIG_EVENTFD
+/* For O_CLOEXEC */
+#include <linux/fcntl.h>
+
+/* Flags for eventfd2. */
+#define EFD_CLOEXEC O_CLOEXEC
+
struct file *eventfd_fget(int fd);
int eventfd_signal(struct file *file, int n);
diff -puN include/linux/syscalls.h~flag-parameters-eventfd include/linux/syscalls.h
--- a/include/linux/syscalls.h~flag-parameters-eventfd
+++ a/include/linux/syscalls.h
@@ -617,6 +617,7 @@ asmlinkage long sys_timerfd_settime(int
struct itimerspec __user *otmr);
asmlinkage long sys_timerfd_gettime(int ufd, struct itimerspec __user *otmr);
asmlinkage long sys_eventfd(unsigned int count);
+asmlinkage long sys_eventfd2(unsigned int count, int flags);
asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len);
int kernel_execve(const char *filename, char *const argv[], char *const envp[]);
diff -puN kernel/sys_ni.c~flag-parameters-eventfd kernel/sys_ni.c
--- a/kernel/sys_ni.c~flag-parameters-eventfd
+++ a/kernel/sys_ni.c
@@ -164,3 +164,4 @@ cond_syscall(sys_timerfd_gettime);
cond_syscall(compat_sys_timerfd_settime);
cond_syscall(compat_sys_timerfd_gettime);
cond_syscall(sys_eventfd);
+cond_syscall(sys_eventfd2);
_
--
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