[PATCH] new valid_signal() function
This patch adds a new function valid_signal() that tests if its argument is
a valid signal number.
The reasons for adding this new function are:
- some code currently testing _NSIG directly has off-by-one errors.
Using this function instead avoids such errors.
- some code currently tests unsigned signal numbers for <0 which is
pointless and generates warnings when building with gcc -W. Using this
function instead avoids such warnings.
I considered various places to add this function but eventually settled on
include/linux/signal.h as the most logical place for it. If there's some
reason this is a bad choice then please let me know (hints as to a better
location are then welcome of course).
Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 78bfb26..0a98f5e 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -220,6 +220,12 @@
INIT_LIST_HEAD(&sig->list);
}
+/* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
+static inline int valid_signal(unsigned long sig)
+{
+ return sig <= _NSIG ? 1 : 0;
+}
+
extern int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p);
extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
extern long do_sigpending(void __user *, unsigned long);