Hi Andrew,
A while back I attempted to fix a little, not at all critical, gcc -W
warning in fs/fcntl.c, during the discussion Matthew Wilcox noted that
there were other locations that did the same thing and at least one
location where there was an off-by-one error. He suggested that one good
way of fixing the whole thing would be to introduce a new valid_signal()
function. This can all be found in the '[PATCH] fs/fcntl.c : don't test
unsigned value for less than zero' thread.
I created a patch to do that and also one that put it to good use and
posted both patches to the list and a few people that I thought were
relevant (same people that are CC: on this mail), but never heard anythng
back and I didn't see the patches get merged either, so now I'm sending
them to you in the hope that you'll merge them in -mm.
Below is the first patch that adds the new function.
-- Jesper Juhl
---------- Forwarded message ----------
Date: Mon, 18 Apr 2005 22:53:26 +0200 (CEST)
From: Jesper Juhl <[email protected]>
To: LKML <[email protected]>
Cc: Matthew Wilcox <[email protected]>, Herbert Xu <[email protected]>,
Christoph Hellwig <[email protected]>
Subject: [PATCH 1/2] 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).
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 <[email protected]>
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);