[PATCH v3 1/2] vfs: Define new syscall getumask.

From: Richard W.M. Jones
Date: Wed Apr 13 2016 - 09:58:25 EST


Define a system call for reading the current umask value.

Signed-off-by: Richard W.M. Jones <rjones@xxxxxxxxxx>
---
include/linux/syscalls.h | 1 +
include/uapi/asm-generic/unistd.h | 4 +++-
kernel/sys.c | 5 +++++
3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index d795472..e96e88f 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -659,6 +659,7 @@ asmlinkage long sys_prlimit64(pid_t pid, unsigned int resource,
struct rlimit64 __user *old_rlim);
asmlinkage long sys_getrusage(int who, struct rusage __user *ru);
asmlinkage long sys_umask(int mask);
+asmlinkage long sys_getumask(void);

asmlinkage long sys_msgget(key_t key, int msgflg);
asmlinkage long sys_msgsnd(int msqid, struct msgbuf __user *msgp,
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 2622b33..e59e880 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -717,9 +717,11 @@ __SYSCALL(__NR_membarrier, sys_membarrier)
__SYSCALL(__NR_mlock2, sys_mlock2)
#define __NR_copy_file_range 285
__SYSCALL(__NR_copy_file_range, sys_copy_file_range)
+#define __NR_getumask 286
+__SYSCALL(__NR_getumask, sys_getumask)

#undef __NR_syscalls
-#define __NR_syscalls 286
+#define __NR_syscalls 287

/*
* All syscalls below here should go away really,
diff --git a/kernel/sys.c b/kernel/sys.c
index cf8ba54..9db526c 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1649,6 +1649,11 @@ SYSCALL_DEFINE1(umask, int, mask)
return mask;
}

+SYSCALL_DEFINE0(getumask)
+{
+ return current_umask();
+}
+
static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
{
struct fd exe;
--
2.7.4