[PATCH 1/2] new valid_signal function

[Jesper Juhl <juhl-lkml@dif.dk>]

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).

A patch that converts most of the code that currently uses _NSIG directly 
to call this function instead is [PATCH 2/2] coming shortly..

Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>

 include/linux/signal.h |    6 ++++++
 1 files changed, 6 insertions(+)

--- linux-2.6.12-rc2-mm3-orig/include/linux/signal.h	2005-04-11 21:20:56.000000000 +0200
+++ linux-2.6.12-rc2-mm3/include/linux/signal.h	2005-04-18 20:09:50.000000000 +0200
@@ -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);



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