Re: [PATCH v2] scripts: checkpatch.pl: add 2 new checks on memset calls

[Joe Perches <joe@perches.com>]

On Wed, 2015-02-25 at 06:59 +0200, Aya Mahfouz wrote:
> On Tue, Feb 24, 2015 at 08:41:23PM -0800, Joe Perches wrote:
> > On Wed, 2015-02-25 at 06:35 +0200, Aya Mahfouz wrote:
> > > On Tue, Feb 24, 2015 at 07:10:52PM -0800, Joe Perches wrote:
> > > > On Wed, 2015-02-25 at 04:40 +0200, Aya Mahfouz wrote:
> > > > > This patch adds 2 new checks on memset calls in the file
> > > > > checkpatch.pl as follows:
> > []
> > > ok, I didn't see your suggestion, sorry.
> > 
> > No worries.
> > 
> > > Can you look at the following
> > > modification before sending the third patch? I don't use $stat because
> > > I get false positives with it.
> > 
> > Please describe the false positives.
> > 
> > 
> 
> ok, here are the relevant warnings issued by checkpatch.pl when using
> $stat for the file drivers/staging/rtl8188eu/os_dep/ioctl_linux.c.
> The only correct results are lines 95, 830, 1031, 1040, 1908. 
> 
> WARNING: Prefer eth_zero_addr() over memset() if the second address is 0x00
> #95: FILE: drivers/staging/rtl8188eu/os_dep/ioctl_linux.c:95:
> +	memset(wrqu.ap_addr.sa_data, 0, ETH_ALEN);
> 
> 
> WARNING: Prefer eth_zero_addr() over memset() if the second address is 0x00
> #775: FILE: drivers/staging/rtl8188eu/os_dep/ioctl_linux.c:775:
> +}

[]

Try this:
---
 scripts/checkpatch.pl | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index d124359..9127c65 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4890,10 +4890,11 @@ sub process {
 			}
 		}
 
-# Check for misused memsets
+# Check for misused memsets then check for memset(foo, 0x00|0xff, ETH_ALEN)
+# calls that could be eth_zero_addr(foo)|eth_broadcast_addr(foo)
 		if ($^V && $^V ge 5.10.0 &&
 		    defined $stat &&
-		    $stat =~ /^\+(?:.*?)\bmemset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*$FuncArg\s*\)/s) {
+		    $stat =~ /^\+(?:\s*$Ident\s*=)?\s*memset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*$FuncArg\s*\)/s) {
 
 			my $ms_addr = $2;
 			my $ms_val = $7;
@@ -4901,10 +4902,22 @@ sub process {
 
 			if ($ms_size =~ /^(0x|)0$/i) {
 				ERROR("MEMSET",
-				      "memset to 0's uses 0 as the 2nd argument, not the 3rd\n" . "$here\n$stat\n");
+				      "memset to 0's uses 0 as the 2nd argument, not the 3rd\n" . "$here\n$line\n");
 			} elsif ($ms_size =~ /^(0x|)1$/i) {
 				WARN("MEMSET",
-				     "single byte memset is suspicious. Swapped 2nd/3rd argument?\n" . "$here\n$stat\n");
+				     "single byte memset is suspicious. Swapped 2nd/3rd argument?\n" . "$here\n$line\n");
+			} elsif ($ms_val =~ /^(?:0x)?0+$/i &&
+				 $ms_size =~ /^ETH_ALEN$/ &&
+				 WARN("PREFER_ETH_ADDR",
+				     "Prefer eth_zero_addr() over memset() if the second address is 0\n" . $herecurr) &&
+				 $fix) {
+				$fixed[$fixlinenr] =~ s/\bmemset\s*\(\s*\Q$ms_addr\E\s*,\s*\Q$ms_val\E\s*,\s*ETH_ALEN\s*\)/eth_zero_addr($ms_addr)/;
+			} elsif ($ms_val =~ /^(?:0xff|255)$/i &&
+				 $ms_size =~ /^ETH_ALEN$/ &&
+				 WARN("PREFER_ETH_ADDR",
+				      "Prefer eth_broadcast_addr() over memset() if the second address is 0xff\n" . $herecurr) &&
+				 $fix) {
+				$fixed[$fixlinenr] =~ s/\bmemset\s*\(\s*\Q$ms_addr\E\s*,\s*\Q$ms_val\E\s*,\s*ETH_ALEN\s*\)/eth_broadcast_addr($ms_addr)/;
 			}
 		}